U.S. patent application number 15/432852 was filed with the patent office on 2017-06-15 for multiple frequency band braking apparatus with magnetic force interposer.
This patent application is currently assigned to Carttronics, LLC. The applicant listed for this patent is Carttronics, LLC. Invention is credited to Thomas K. Khuu.
Application Number | 20170166232 15/432852 |
Document ID | / |
Family ID | 46718245 |
Filed Date | 2017-06-15 |
United States Patent
Application |
20170166232 |
Kind Code |
A1 |
Khuu; Thomas K. |
June 15, 2017 |
MULTIPLE FREQUENCY BAND BRAKING APPARATUS WITH MAGNETIC FORCE
INTERPOSER
Abstract
A shopping cart wheel includes a braking apparatus, and
electronics that control the braking apparatus in response to
wireless signals. The wireless signals include low frequency
electromagnetic signals within a low frequency band and high
frequency signals within a high frequency band. The braking
apparatus includes a moveable interposer and an interposer
controller where the moveable interposer is moved between braking
and non-breaking positions at least partially with magnetic
force.
Inventors: |
Khuu; Thomas K.; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Carttronics, LLC |
San Diego |
CA |
US |
|
|
Assignee: |
Carttronics, LLC
San Diego
CA
|
Family ID: |
46718245 |
Appl. No.: |
15/432852 |
Filed: |
February 14, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15227671 |
Aug 3, 2016 |
9610965 |
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15432852 |
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|
14661920 |
Mar 18, 2015 |
9409443 |
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15227671 |
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|
14079931 |
Nov 14, 2013 |
8985282 |
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14661920 |
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13034292 |
Feb 24, 2011 |
8602176 |
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14079931 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60B 33/0049 20130101;
B60B 33/0094 20130101; B62B 5/0423 20130101; B60B 33/0092 20130101;
B62B 2301/00 20130101; B60B 2900/3318 20130101; F16D 2065/022
20130101; F16D 2121/24 20130101; B60B 33/0073 20130101; F16D
2121/20 20130101; B60B 33/0086 20130101; Y10T 16/195 20150115; B60B
33/0039 20130101; B60B 2200/432 20130101; B60B 33/0057 20130101;
F16D 63/006 20130101; F16D 65/16 20130101; B60B 33/0068 20130101;
B60B 2380/12 20130101; F16D 2121/14 20130101; F16D 2125/40
20130101 |
International
Class: |
B62B 5/04 20060101
B62B005/04; F16D 63/00 20060101 F16D063/00; F16D 65/16 20060101
F16D065/16; B60B 33/00 20060101 B60B033/00 |
Claims
1. A shopping cart wheel comprising: a non-rotating component; a
rotating component configured to rotate relative to the
non-rotating component unless the shopping cart wheel is in a
braking configuration where a moveable interposer is lodged between
the rotating component and the non-rotating component; a low
frequency antenna; a high frequency antenna; a low frequency
receiver electrically connected to the low frequency antenna and
configured to receive one or more low frequency signals through the
low frequency antenna, the one or more low frequency signals
transmitted within a low frequency band; a high frequency receiver
electrically connected to the high frequency antenna and configured
to receive one or more high frequency wireless signals through the
high frequency antenna, the one or more high frequency wireless
signals transmitted within a high frequency band having a lower
limit greater than an upper limit of the low frequency band; and an
interposer controller connected to the low frequency receiver and
the high frequency receiver, the interposer controller configured
to place the shopping cart wheel in the braking configuration in
response to the one or more low frequency signals and to take the
shopping cart wheel out of the braking configuration in response to
the one or more high frequency signals, the interposer controller
configured to take the shopping cart out of the braking
configuration by moving the moveable interposer from being
positioned between the rotating component and the non-rotating
component at least partially using magnetic force between the
moveable interposer and a component of the interposer
controller.
2. The shopping cart wheel of claim 1, wherein the high frequency
band is defined by an Institute of Electrical and Electronics
Engineers (IEEE) 802.11 standard.
3. The shopping cart wheel of claim 1, wherein the interposer
controller is configured to determine a state of the shopping cart
wheel and, based on the state and a received wireless signal, to
place the shopping cart wheel in the braking configuration.
4. The shopping cart wheel of claim 1, wherein the controller is
configured to: place the shopping cart wheel in the braking
configuration in response to the low frequency receiver receiving a
first low frequency wireless signal; place the shopping cart wheel
out of the braking configuration in response to the low frequency
receiver receiving a second low frequency wireless signal; place
the shopping cart wheel in the braking configuration in response to
the high frequency receiver receiving a first high frequency signal
wireless signal; and place the shopping cart wheel out of the
braking configuration in response to the high frequency receiver
receiving a second high frequency wireless signal.
5. The shopping cart wheel of claim 4, wherein a frequency of the
first low frequency signal and a frequency of the second low
frequency signal are less than 9 KHz.
6. The shopping cart wheel of claim 5, wherein the frequency of the
first low frequency signal and the frequency of the second low
frequency signal are about 8 KHz.
7. The shopping cart wheel of claim 4, wherein a frequency of the
first high frequency signal and a frequency of the second high
frequency signal are greater than 2.3 GHz.
8. The shopping cart wheel of claim 7, wherein the frequency of the
first high frequency signal and the frequency of the second high
frequency signal are about 2.4 GHz.
9. A shopping cart wheel comprising: a rotating component having a
rotating component feature; a non-rotating component having a
non-rotating component feature; a moveable interposer configured to
inhibit rotation of the rotating component relative to the
non-rotating component when the moveable interposer is in a braking
position where the moveable interposer is positioned between the
rotating component feature and the non-rotating component feature
and configured to not inhibit rotation of the rotating component
relative to the non-rotating component when the moveable interposer
is in a non-braking position where the moveable interposer is not
positioned between the rotating component feature and the
non-rotating component feature; a low frequency antenna; a high
frequency antenna; a low frequency receiver electrically connected
to the low frequency antenna and configured to receive one or more
low frequency signals through the low frequency antenna; a high
frequency receiver electrically connected to the high frequency
antenna and configured to receive one or more high frequency
wireless signals; and an interposer controller connected to the low
frequency receiver and the high frequency receiver, the interposer
controller configured to move the moveable interposer between the
braking position and the non-braking position in response to the
one or more low frequency signals and the one or more high
frequency signals, where movement of the moveable interposer to the
non-braking position is at least partially due to magnetic force
between the moveable interposer and a component of the interposer
controller.
10. The shopping cart wheel of claim 9, wherein the interposer
controller comprises electronics configured to determine a state of
the shopping cart wheel and, based on the state and a received
wireless signal, to generate a first control signal to place the
moveable interposer in the braking position and a second control
signal to place the moveable interposer in the non-braking
position.
11. The shopping cart wheel of claim 9, wherein the controller is
configured to: place the moveable interposer in the braking
position in response to the low frequency receiver receiving a
first low frequency wireless signal; place the moveable interposer
in the non-braking position in response to the low frequency
receiver receiving a second low frequency wireless signal; place
the moveable interposer in the braking position in response to the
high frequency receiver receiving a first high frequency signal
wireless signal; and place the moveable interposer in the
non-braking position in response to the high frequency receiver
receiving a second high frequency wireless signal.
12. The shopping cart wheel of claim 11, wherein a frequency of the
first low frequency signal and a frequency of the second low
frequency signal are less than 9 KHz.
13. The shopping cart wheel of claim 12, wherein the frequency of
the first low frequency signal and the frequency of the second low
frequency signal are about 8 KHz.
14. The shopping cart wheel of claim 11, wherein a frequency of the
first high frequency signal and a frequency of the second high
frequency signal are greater than 2.3 GHz.
15. The shopping cart wheel of claim 14, wherein the frequency of
the first high frequency signal and the frequency of the second
high frequency signal are about 2.4 GHz.
16. A shopping cart wheel comprising: a non-rotating component; a
rotating component configured to rotate relative to the
non-rotating component unless the shopping cart wheel is in a
braking configuration where a moveable interposer is lodged between
the rotating component and the non-rotating component; an
interposer controller configured to place the shopping cart wheel
in the non-braking configuration at least partially by moving the
moveable interposer with magnetic force between the moveable
interposer and a component of the interposer controller; and
electronics configured to place the shopping cart wheel in the
non-braking configuration in response to a wireless signal received
within a first frequency band defined by an Institute of Electrical
and Electronics Engineers (IEEE) 802.11 standard, the electronics
configured to place the shopping cart wheel in the braking
configuration in response to an electromagnetic signal received
within a second frequency band lower than the first frequency
band.
17. The shopping cart wheel of claim 16, wherein the electronics
are configured to place the shopping cart wheel in the braking
configuration in response to another wireless signal received
within the first frequency band and to place the shopping cart
wheel in the non-braking configuration in response to another
electromagnetic signal received within the second frequency
band.
18. The shopping cart wheel of claim 17, wherein the first
frequency band includes 2.4 GHz and the second frequency band
includes 8 KHz.
19. The shopping cart wheel of claim 17, wherein the rotating
component comprises a wall and the non-rotating component comprises
a non-rotating component feature and where the shopping cart wheel
is in the braking configuration at least when a moveable interposer
is positioned in a braking position where the moveable interposer
is between the wall and the non-rotating component feature, the
shopping cart wheel further comprising a release mechanism
configured to release, the moveable interposer from a non-braking
position to allow the moveable interposer to move to the braking
position, the electronics configured to actuate the release
mechanism to release the moveable interposer in response to
detection of at least one of the electromagnetic signal and the
another wireless signal.
20. The shopping cart wheel of claim 16, wherein the moveable
interposer moves to the braking position at least partially due to
gravity.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/227,671, filed Aug. 3, 2016, which is a continuation of U.S.
application Ser. No. 14/661,920, filed Mar. 18, 2015, now U.S. Pat.
No. 9,409,443 which is a continuation of U.S. application Ser. No.
14/079,931, filed Nov. 14, 2013, now U.S. Pat. No. 8,985,282 which
is a continuation of U.S. application Ser. No. 13/034,292, filed on
Feb. 24, 2011, now U.S. Pat. No. 8,602,176, which are incorporated
by reference in their entirety, herein.
FIELD
[0002] This invention generally relates to brakes and more
particularly to a multiple frequency braking mechanism with a
magnetic force interposer.
BACKGROUND
[0003] Braking mechanisms are used to stop rotation of a rotating
component where the rotating component may be part of machinery or
a wheel. Brakes, for example, are used to stop or restrict motion
of a vehicle by restricting rotation of a wheel of the vehicle. One
use for brakes includes providing a mechanism for restricting
motion of a shopping cart or dolly to reduce theft or other
unauthorized movement of the shopping cart.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1A is a block diagram of a braking mechanism for
restricting rotation of a rotating component before a moveable
interposer is moved to a braking position in accordance with first
exemplary embodiments.
[0005] FIG. 1B is a block diagram of the braking mechanism where
the moveable interposer is moved toward the non-rotating component
feature as the rotating component rotates in accordance with the
first exemplary embodiments.
[0006] FIG. 1C is a block diagram of a braking mechanism in the
braking configuration when the moveable interposer is positioned
between the non-rotating component feature and the rotating
component feature in accordance with the first exemplary
embodiments.
[0007] FIG. 1D is a block diagram of the braking mechanism where
the moveable interposer is moved to the braking position by a
mechanical actuator and slight rotation of the rotating component
in accordance with second exemplary embodiments.
[0008] FIG. 1E is a block diagram of a wheel braking apparatus
connected to a wheel after the braking apparatus is placed in the
braking configuration and the ball bearing has been released in
accordance with the second exemplary embodiments.
[0009] FIG. 1F is a block diagram of the wheel braking apparatus
connected to the wheel where the braking apparatus is in a braking
configuration and the ball bearing is in a forward braking position
in accordance with the second exemplary embodiments.
[0010] FIG. 1G is a block diagram of the wheel braking apparatus
prior to the bearing barrier interfacing with the ball bearing as
the rotating component is rotated in accordance with the second
exemplary.
[0011] FIG. 1H is block diagram of the wheel braking apparatus in
the non-braking configuration where the ball bearing is attracted
to the mechanical actuator in accordance with the second exemplary
embodiments.
[0012] FIG. 2 is a block diagram of electronics connected to the
bearing release mechanism where the bearing release mechanism
includes an electric motor and a threaded block.
[0013] FIG. 3 is an illustration of a perspective view of a caster
assembly including the braking apparatus connected to the wheel and
mounted on a yoke in accordance with the exemplary embodiment of
the invention.
[0014] FIG. 4A is an illustration of a top view of a printed
circuit board (PCB) assembly
[0015] FIG. 4B is an illustration of a side view of the PCB
assembly.
[0016] FIG. 5A is an illustration of an exploded view of the wheel
and braking apparatus in accordance with the first exemplary
embodiments.
[0017] FIG. 5B is an illustration of another exploded view of the
wheel and braking apparatus in accordance with the exemplary
embodiment.
[0018] FIG. 6A is an illustration of a side view of the inner
portion of the non-rotating component housing.
[0019] FIG. 6B is an illustration of a side view of the outer
portion of the non-rotating component housing.
[0020] FIG. 6C is an illustration of a top view of the non-rotating
component housing at line A-A of FIG. 6B.
[0021] FIG. 7A is an illustration of a perspective view of the
braking assembly including the hub interface component, the PCB
assembly, the ball bearing, and the non-rotating housing.
[0022] FIG. 7B is an illustration of a side view of the braking
assembly.
[0023] FIG. 8A is an illustration of a cross sectional side view of
the braking assembly taken along line B-B of FIG. 7B when the
braking apparatus is in the braking configuration and the bearing
is in a forward braking position.
[0024] FIG. 8B is an illustration of a cross sectional side of the
braking assembly taken along line B-B of FIG. 7B when the braking
apparatus is in the non-braking configuration and the ball bearing
is contained in the bearing release mechanism.
[0025] FIG. 8C is an illustration of a cross sectional side of the
braking assembly taken along line B-B of FIG. 7B when the braking
apparatus is in the braking configuration and the ball bearing is
released into the bearing channel.
[0026] FIG. 8D is an illustration of a cross sectional side view of
the braking assembly taken along line B-B of FIG. 7B when the
braking apparatus is in the braking configuration and the ball
bearing is within one of the bearing grooves while the wheel is
rotated in the forward direction.
[0027] FIG. 8E is an illustration of a cross sectional side view of
the braking assembly taken along line B-B of FIG. 7B when the
braking apparatus is in the braking configuration and the ball
bearing is within one of the bearing grooves while the wheel is
rotated in the reverse direction.
[0028] FIG. 9A is an illustration of a side view of an inner
portion of the hub interface component in an example where the hub
interface component forms a clutch mechanism with features of the
wheel hub when installed in the wheel hub.
[0029] FIG. 9B is an illustration of a side view of the side of the
wheel hub for engaging the hub interface component.
[0030] FIG. 9C is an illustration of the hub interface component
inserted into the wheel hub to form the clutch mechanism.
[0031] FIG. 10 is an illustration of an exploded view of the wheel
and braking apparatus in accordance with the second exemplary
embodiment where the ball bearing is at least partially moved by
magnetic force to the non-braking position.
[0032] FIG. 11 is an illustration of a side view of the inner
portion of the non-rotating component housing for the example where
the ball bearing is moved to the non-braking position with magnetic
force.
[0033] FIG. 12 is an illustration of a side view of the hub
interface component where the hub interface component includes
three bearing grooves.
[0034] FIG. 13A is an illustration of a cross sectional side view
of the braking assembly 700 taken along line B-B of FIG. 7B when
the braking apparatus is in the non-braking configuration in
accordance with the second exemplary embodiments.
[0035] FIG. 13B is an illustration of a cross sectional side view
of the braking assembly 700 taken along line B-B of FIG. 7B as the
braking apparatus is configured to the braking configuration in
accordance with the second exemplary embodiments.
[0036] FIG. 14 is a flow chart of a method of inhibiting rotation
of a rotating component in accordance with the first exemplary
embodiments.
[0037] FIG. 15 is a flow chart of a method of inhibiting rotation
of a rotating component in accordance with the second exemplary
embodiments.
DETAILED DESCRIPTION
[0038] Braking systems on shopping carts can be used to reduce
theft by wirelessly activating a brake on a particular shopping
cart to restrict motion of the shopping cart. The brake is engaged
and disengaged in response to wireless signals that may be
transmitted from particular locations in a shopping area or
building. When a cart passes near those locations under certain
conditions, the brake is activated. For example, if an attempt is
made to remove a cart from a store and the braking system has not
been notified that exit from the store is authorized, the brake is
activated when passing through the store exit where a wireless
transmitter transmits a wireless signal. Conventional braking
mechanisms for shopping carts and other vehicles, however, are
limited in that they are often large and difficult and/or expensive
to attach to existing vehicle designs. The large size may cause the
cart to be difficult to maneuver. Further, many conventional
systems include parts that are susceptible to wear and must be
replaced or repaired which may add significant costs to maintaining
the anti-theft system. In addition, conventional designs often
require numerous moving parts resulting in increased cost and less
reliability.
[0039] These limitations and others are reduced or eliminated by
the embodiments of the invention discussed below. For example, the
use of brake shoes or other friction devices for use as the primary
mechanism for restricting rotation of the wheel are eliminated. In
the exemplary embodiment, the braking actuator does not participate
in the mechanical braking action and will not suffer from feedback
wear. This independence facilitates recovery of non-consumable
components such as the electronics for reuse, recycling, or proper
disposal. Further, at least one of the embodiments may easily be
integrated with standard wheels with minimal modifications to the
standard wheel. As a result, cost is reduced due to economies of
scale. Preventative maintenance and associated costs are reduced
with the integration into a standard wheel form factor since the
end user is able to perform routine servicing as well as
installation without specialized training or tools. For example,
the wheel hub and attached tread (tire) could be replaced by
detaching the non-rotating parts and remounting them onto a new
wheel hub. In addition, the number of moving parts can be
significantly reduced from the numbers of conventional systems.
This permits the fundamental design to be more scalable for all
casters types and wheel sizes, as well as providing the braking
force required for a given application. In addition, sensitivity to
temperature and degradation from nonuse are minimized.
[0040] In some examples, a wheel braking apparatus includes
components that inhibit the rotation of a wheel when a ball bearing
is placed in a braking position between a bearing wall of a
non-rotating component and a bearing barrier of a hub interface
component that is at least resistively connected to a hub of the
wheel. In response to a wireless signal, the ball bearing is
released from a non-braking position and allowed to travel to a
braking position between a bearing barrier of one side of a bearing
groove and the bearing wall of the non-rotating component. In the
braking position, therefore, the ball bearing is interposed, or
otherwise lodged, between the bearing wall of the non-rotating
component and one side of the bearing grove of the hub interface
component. As discussed below, rotation of the wheel may be
required to allow the ball bearing to enter the bearing groove in
some embodiments. Further wheel rotation may be needed once the
ball bearing is within the bearing groove in order for the bearing
groove to rotate relative to the ball bearing wall to place the
ball bearing in the braking position between the bearing wall and
the bearing barrier. In the examples discussed below, the hub
interface component includes several recessed features on the outer
surface of the hub interface component that interface to protruding
features on the inside of the wheel hub. When the bearing is in the
braking position, the hub interface component moves relative to the
wheel hub only when a torque threshold is exceeded and the recessed
features can be moved relative to the protruding features extending
into the recessed features. Typically, the relative rotation of the
hub interface component to the wheel hub is stopped when each
recessed feature reaches the next adjacent protruding feature. Such
a mechanism reduces "flat-spotting" where abrasion of the tire
occurs in one contact area or "spot" of the wheel surface when the
braked wheel is dragged along the ground.
[0041] The invention may be implemented using various techniques
and components in numerous and diverse embodiments. In addition to
a discussion of the general operation and structure of the several
embodiments, the disclosure includes a description of embodiments
that at least partially utilize gravity to move a movable
interposer to the braking position and embodiments that at least
partially use magnetic force to move the moveable interposer to the
non-braking position. As discussed herein, the first exemplary
embodiments refer to one or more examples where the movement of the
moveable interposer to the braking position is at least partially
due to gravity. The second exemplary embodiments refer to one or
more examples where movement of the moveable interposer to the
non-braking position is at least partially due to magnetic
force.
[0042] FIG. 1A, FIG. 1B, FIG. 1C, and FIG. 1D are block diagrams of
a braking mechanism 10 for restricting rotation of a rotating
component 12 where FIG. 1A, FIG. 1B, and FIG. 1C are in accordance
with the first exemplary embodiments and FIG. 1D is in accordance
with the second exemplary embodiments. Although significant
advantages may be realized when the braking mechanism techniques
are implemented with a braking apparatus for a wheel, the braking
mechanism 10 may be used in any of numerous machines and
applications. The discussion with reference to FIG. 1A, FIG. 1B,
FIG. 1C, and FIG. 1D provides a description of the general
structure and principles that can be used to implement a braking
mechanism within various environments. Accordingly, the rotating
component 12 is any wheel, disc, hub, axle or other structure that
rotates relative to a non-rotating component 14, where the
non-rotating component 14 is any device or structure that is
stationary from a point of reference relative to the rotating
component 12. The components 12, 14 may be part of a clutch, brake,
or other assembly.
[0043] To invoke braking, an interposer controller 16 interposes,
or otherwise lodges, a movable interposer 18 between a non-rotating
component feature 20 and a rotating component feature 22 to
restrict rotation of the rotating component 12 relative to the
non-rotating component 14. The features 20, 22 on the non-rotating
component 14 and the rotating component 12 may be any protrusion,
recess, attached element, or other structure that does not allow
the rotating component feature 22 to travel past the non-rotating
component feature 20 when the moveable interposer 18 is positioned
between the two features 20, 22. In the examples discussed below,
the moveable interposer 18 is a ball bearing, the rotating
component feature 22 is a groove, and the non-rotating component
feature 20 is a protrusion forming a bearing wall. Other types of
moveable interposers, rotating components features, and
non-rotating component features can be used.
[0044] The interposer controller 16 is any combination of
mechanical and/or electrical components that can move the moveable
interposer 18 into the braking position between the features 20,
22. For the examples discussed below, the interposer controller 16
includes a mechanical actuator responsive to electronics to release
a ball bearing into a groove that holds and carries the ball
bearing as the rotating component 12 rotates until the ball bearing
is interposed between a side of the groove and the protrusion
forming the non-rotating component feature. The mechanical actuator
may include any combination of electric motors, solenoids, magnets,
scissor arms, rotating springs, springs, mechanical arms and/or
guides. Accordingly, the interposer controller 16 may use a
combination of mechanical force from a mechanical actuator,
rotational motion of the rotating component 12, magnetic force,
and/or gravity to place the moveable interposer 18 in the braking
position between the rotating component feature 20 and the
non-rotating component feature 22 depending on the particular
implementation.
[0045] FIG. 1A is an illustration of the braking mechanism 10 in
the non-braking configuration before the moveable interposer 18 is
moved to the braking position. The dashed line indicates the
movement of the moveable interposer 18 after the interposer
controller 16 initiates the braking process. The moveable
interposer 18 travels to the rotating component feature 22 at least
partially in response to gravity. In FIG. 1B, the moveable
interposer 18 is moved toward the non-rotating component feature 10
as the rotating component 12 rotates. FIG. 1C is an illustration of
the braking mechanism 10 in the braking configuration when the
moveable interposer is positioned between the non-rotating
component feature 20 and the rotating component feature 22. The
rotating component 12 cannot rotate past the non-rotating component
14 in this configuration. In some situations, rotation is possible
in the reverse direction until the moveable interposer 18 is again
positioned between the two features 20, 22.
[0046] To release the braking mechanism 10 from the braking
configuration, the interposer controller 16 is reconfigured to
allow the moveable interposer 18 to move to a position that allows
the two features 20, 22 to rotate past each other. In some cases,
reverse rotation of the rotating component may be required to move
the moveable interposer 18 from the braking position.
[0047] FIG. 1D is a block diagram of the braking mechanism 10 where
the moveable interposer is moved to the braking position by a
mechanical actuator and slight rotation of the rotating component.
As discussed below, one implementation of the exemplary braking
mechanism of FIG. 1D includes an interposer controller 16 that has
a mechanical actuator that places a magnetic ball bearing between
the two features 20, 22. As the rotating component rotates relative
to the non-rotating component 14, the ball bearing becomes lodged
between the non-rotating component feature 20 and the rotating
component feature 22. To place the braking mechanism 10 in the
non-braking configuration, the mechanical actuator is retracted
such that the moveable interposer is removed from between the two
features 20, 22. For the example, movement of the moveable
interposer is at least partially due to magnetic force. Where the
moveable interposer is a magnetic ball bearing, retracting a
magnetically attractive component into a recessed position allows
the ball bearing to be attracted to the magnetically attractive
component and be withdrawn from the braking position between the
two features.
[0048] For the examples discussed below, the interposer controller
is controlled, at least partially, by wireless signals. The braking
mechanism 10, however, may be controlled by other techniques. The
braking mechanism may respond to inputs through user controls
connected to the controller through wires, for example. In
addition, actions by the braking mechanism 10 may be in response to
time, speed of rotation, or other events or circumstances.
[0049] FIG. 1E, FIG. 1F, FIG. 1G, and FIG. 1H are block diagrams of
an example of the braking mechanism 10 where the braking mechanism
is a wheel braking apparatus 100 connected to a wheel 102. FIG. 1E
represents the braking apparatus 100 in initial stages after being
placed in the braking configuration and FIG. 1F represents the
braking apparatus 100 when a ball bearing is in the forward braking
position in an example in accordance with FIG. 1A, FIG. 1B, and
FIG. 1C. FIG. 1G represents the braking apparatus 100 after being
placed in the braking configuration just prior to the ball bearing
being lodged between the rotating component feature and the
non-rotating component feature and FIG. 1H represents the braking
apparatus 100 when a ball bearing is in the forward braking
position in an example in accordance with FIG. 1D.
[0050] The diagrams may not be to scale, do not necessarily depict
the shapes of the components, and are intended to generally convey
components of the system 100 and the relationships between the
components. The wheel 102 includes a tire (tread) 104 mounted on a
wheel hub 106. For the examples herein, the tire 104 is hard rubber
or polyurethane and is permanently mounted to the wheel hub 106
although other types of tires may be used. Also, for the examples
discussed herein, the hub 106 is molded nylon and includes a wheel
bearing 108 that can be mounted on an axle, kingpin, or bolt
connected to a yoke assembly (not shown in FIG. 1E, FIG. 1F, FIG.
1G, or FIG. 1H). The wheel can rotate in either direction and, for
purposes of reference, the wheel rotates clockwise (forward
rotation 109) when the wheel moves forward.
[0051] The wheel braking apparatus 102 includes a hub interface
component 110 that is attached to the wheel hub 106. The hub
interface component 110 is connected to the wheel hub 106 through a
clutch mechanism in the exemplary embodiment. The clutch mechanism
allows the wheel hub 106 to rotate relative to the hub interface
component 110 when a torque threshold of torque between hub 106 and
the component 110 is exceeded. An example of a suitable clutch
mechanism is discussed below. In some circumstances, the clutch
mechanism is omitted and the hub interface component 110 is
securely affixed to the wheel hub 106. Also, in some circumstances,
the hub interface component may be integrated with the wheel hub or
the features of the hub interface component may be directly
implemented on the wheel hub.
[0052] When the braking apparatus 100 is in the freewheeling,
non-braking configuration, the hub interface component 110 rotates
with the wheel hub 106 relative to a non-rotating component 112.
The non-rotating component 112 is attached to, connected to, or
otherwise in contact with a yoke such that it cannot rotate
relative to the yoke. For the example discussed below, the
non-rotating component 112 is a plastic housing that includes a
recess configured to accept one arm of the yoke when the wheel is
mounted onto the yoke. The non-rotating housing is held in place by
the yoke and an axle bolt. Other techniques and configurations may
be used to form the non-rotating component 112. For example, the
non-rotating component may include an axle that does not
rotate.
[0053] In the braking configuration, a ball bearing 114 is
positioned within a bearing groove 116 in the hub interface
component 110 and is interposed between a bearing wall 118 of the
non-rotating component 112 and one side of the bearing groove 116.
When the ball bearing 114 is not within the bearing groove 116, the
bearing groove 116 is able to rotate past the bearing wall 118 as
the wheel is rotated. If the ball bearing 114 is within the bearing
groove 118, however, the ball bearing 114 contacts the bearing wall
118 and one end of the bearing groove 116 and the bearing groove
116 cannot rotate past the bearing wall 118. The ball bearing 114
in this situation is positioned between the bearing wall 118 and
either a first bearing barrier 120 or second barrier 122 of the
bearing groove 116 where the bearing barriers 120, 122 are the ends
of the groove 116. As a result, the hub interface component 110 is
not able to rotate relative to the non-rotating component 112. The
position of the ball bearing 114 in the braking configuration
depends on the direction that the wheel 102 is being rotated before
braking occurs. In one direction (forward rotation 109), the ball
bearing 114 becomes interposed between the first bearing barrier
122 at one end of the bearing groove 116 and a first side 124 of
the bearing wall 118. In the other direction (reverse rotation
125), the ball bearing 114 becomes interposed between the second
bearing barrier 122 at the other side of the groove and the other
side 126 of the bearing wall 118. The braking apparatus 100 may
have more than one bearing wall 118. Therefore, the first side of
the bearing wall and the second side of the bearing wall are
sometimes referred to herein as the first bearing wall and the
second bearing wall, respectively. The first bearing wall 124 and
the second bearing wall 126 may be different sides of single
bearing wall 118. FIG. 1D represents the braking apparatus 100
where the ball bearing 114 is in a forward braking position.
Although the block diagrams in FIG. 1E, FIG. 1F, FIG. 1G, and FIG.
1H show a single bearing groove 116, the hub interface component
110 may include any number of bearing grooves 116. As discussed
below with reference to one example, six bearing grooves 116 may be
used. Such an implementation decreases the delay from the release
of the ball bearing 114 to braking and decreases the time to return
to the non-braking position via reverse rotation. The bearing
groove 116 is any recess, cup, or other feature that is capable of
holding and guiding the ball bearing 114 to the braking position
where the bearing prevents the bearing groove 116 to rotate past
the non-rotating component 112. Accordingly, the bearing groove 116
is one example of the rotating component feature 22 discussed
above. Although in the exemplary embodiment the bearing groove 116
is formed within the hub interface component, other techniques may
be used to provide a bearing groove 116. For example, where the
clutch mechanism is omitted, one or more bearing grooves 116 may be
formed directly in the wheel hub and the hub interface component
may be omitted. In another example, the bearing groove 116 may be a
slightly longer than the diameter of the ball bearing 114 and may
be a cup-shaped recess.
[0054] FIG. 1E and FIG. 1F are illustrations in accordance with the
first exemplary embodiments. FIG. 1E shows the ball bearing 114
traveling from a non-braking position 128 in a bearing release
mechanism 130 to a bearing port 132 at the end of a bearing channel
134. FIG. 1F shows the ball bearing 114 in one braking position
where the ball bearing 114 is between the first bearing barrier 120
of the bearing groove and the first side 124 of the bearing wall
118. The bearing release mechanism 130 maintains the ball bearing
114 in the non-braking position 128 until electronics 136 actuate
the bearing release mechanism 130 in response to receiving a
wireless signal 138. After the ball bearing 114 is released, the
ball bearing 114 travels through the bearing channel 134 over a
bearing path 139 through the bearing port 132. The ball bearing 114
enters the bearing groove 116 when the bearing groove 116 is
aligned with the bearing port 132. If the bearing port 132 is not
aligned with the bearing groove 116 when the bearing is at the
bearing port 132, the ball bearing 114 remains at the end of the
bearing channel 134 in the bearing port 132 while the non-grooved
portions of the hub interface component 110 slide past the ball
bearing 114 as the wheel 102 is rotated. Once the wheel 102 is
sufficiently rotated to align the bearing port 132 with the bearing
groove 116, the bearing is allowed to fall into the bearing groove
116. As the wheel 102 is rotated further, the bearing groove 116 is
rotated toward the bearing wall 118 until the ball bearing 114
reaches a braking position. The bearing port 132 may be aligned
with the bearing groove 116 by rotating the wheel 102 in either
direction. Further, after the ball bearing 114 is within the
bearing groove 116, the wheel 102 can be rotated in either
direction to place the ball bearing in either the forward braking
position or the reverse braking position.
[0055] The bearing release mechanism 130 is any device or apparatus
that can maintain the ball bearing 114 in the non-braking position
128 and be activated to release the ball bearing 114 in response to
signals generated by electronics 136. As discussed below in further
detail, an example of a suitable release mechanism 130 includes a
threaded block connected to a threaded screw shaft of an electric
motor. In the non-braking (freewheeling) position, the threaded
block is positioned over the bearing channel 134 such that the ball
bearing 114 cannot enter the bearing channel 134. The electronics
138 activate the bearing release mechanism 130 in this
implementation by applying power to the motor. As the motor rotates
the threaded screw shaft, the block is threaded onto the shaft and
pulled to a position that allows the ball bearing to travel into
the bearing channel and, consequently, into the bearing groove 116.
Other examples of the bearing release mechanism 130 include
solenoids and magnetic devices. Accordingly, the bearing release
mechanism 130 is an example of at least a portion of the interposer
controller 16.
[0056] As the wheel 102 is further rotated, the ball bearing 114 is
carried within the bearing groove 116 until it comes in contact
with the bearing wall 118. In some circumstances, a bearing
deflector (not shown in FIG. 1E or FIG. 1F) keeps the ball bearing
114 from falling into the bearing release mechanism 130 when the
wheel 102 is rotated in a particular direction. The bearing
deflector may be a section of spring steel angled to cause the ball
bearing to "jump" the opening 140 to the bearing release mechanism
130 when the wheel 102 is rotated in one direction (e.g. forward
rotation 109). When the wheel 102 is rotated in the opposite
direction (reverse rotation 125), however, the bearing deflector
130 causes the ball bearing 114 to fall into the opening 140 when
the ball bearing 114 reaches the opening 140. If the braking
apparatus 100 is in the braking configuration, the bearing release
mechanism 130 remains in the retracted position and the ball
bearing falls through the bearing channel 134. If the bearing
release mechanism 130 includes a motor and threaded block, for
example, the threaded block remains retracted and the ball bearing
falls through the bearing channel 134. Continued rotation results
in the ball bearing 114 being brought back to one of the braking
positions between the bearing wall 118 and one of the bearing
barriers 122, 124 of the bearing groove 116. If the threaded block
is not retracted, the ball bearing 114 returns to the non-braking
position 128 within the bearing release mechanism 130.
[0057] For the example where the bearing release mechanism 130
includes the motor and threaded block, the braking apparatus 100 is
placed in the non-braking (freewheeling) position by rotating the
motor to move the threaded block into a position that does not
allow the ball bearing 114 to enter the bearing channel 134. The
return to the non-braking configuration occurs after the wheel 102
is rotated in a direction that allows the ball bearing 114 to enter
the opening 140 of the bearing release mechanism 130.
[0058] As discussed below, the electronics 136 include a receiver
that is configured to receive at least one wireless signal 138
within at least one frequency band. In some deployments of the
braking apparatus 100, the braking apparatus 100 is connected to a
wheel 102 on a shopping cart and the wireless signal 138 is
generated by a transmitter near an exit of a store. One suitable
implementation includes installing one or more wire loops or other
antennas in the floor near the store exit where the transmitters
transmit wireless signals at a relatively low frequency.
Transmitters transmitting higher frequency signals can be used to
control the braking apparatus from distances farther than the low
frequency transmitters. In response to receipt by the receiver of
wireless signals 138 transmitted through the antennas, the
electronics 136 set the braking apparatus to the appropriate
configuration.
[0059] Therefore, the braking apparatus 100 of FIG. 1E and FIG. 1F
is an example of the braking mechanism 10 where the moveable
interposer 18 is a ball bearing 114, the rotating component feature
22 is a bearing groove 116, the non-rotating component feature 20
is a bearing wall 118 and the movement of the ball bearing is
caused at least partially by gravity. In the example, the rotating
component 12 is the hub interface component 110 and the
non-rotating component 14 is the non-rotating component 112. In
this example, the interposer controller 16 is implemented with
electronics controlling a bearing release mechanism 130 and a
rotating hub interface component 110.
[0060] FIG. 1G and FIG. 1H are illustrations in accordance with the
second exemplary embodiments. For the example of FIG. 1G and FIG.
1H, therefore, the ball bearing 114 is magnetic and a mechanical
actuator 142 is made of a magnetically attractive material or
includes a magnetically attractive component 144. In some
situations, the mechanical actuator 142 may be magnetic and the
ball bearing 114 may be made of a magnetically attractive material
or include a magnetically attractive component. For the example,
the ball bearing is placed in the braking position by extending the
mechanical actuator through the bearing channel and pushing the
ball bearing 114 into the region where it becomes interposed
between the bearing barrier 120 of the bearing groove and the
bearing wall 118 of the non-rotating component. FIG. 1G shows the
bearing just prior to the bearing barrier 120 interfacing with the
ball bearing 114 as the rotating component is rotated. FIG. 1H
shows the braking apparatus in the non-braking configuration where
the ball bearing is attracted to the mechanical actuator and pulled
back through the bearing channel and out of the region where the
ball bearing can be interposed between the bearing groove and the
bearing wall. As discussed below, the mechanical actuator 142 is an
electric motor with a threaded block that is extended and retracted
by rotating the electric motor.
[0061] FIG. 2 is a block diagram of the electronics 136 connected
to the bearing release mechanism 130 where the bearing release
mechanism 130 includes an electric motor 202 and a threaded block
204. Accordingly, FIG. 2 is a block diagram of portions of the
braking apparatus 100 in an example where the bearing release
mechanism 130 includes a motor 202 and a threaded block 204. The
block diagram of FIG. 2 is in accordance with the first and second
exemplary embodiments. The electronics 136 include any combination
of electrical components, integrated circuits (ICs) Application
Specific Integrated Circuits (ASICs), resistors, capacitors,
inductors, connections, printed circuit boards, wires, and/or other
electrical devices that perform the functions described herein. An
example of a suitable implementation of the electronics 136
includes soldering electrical devices onto a printed circuit board
(PCB) 206 where the PCB 206 fits within a non-rotating housing of
the braking apparatus 100. The electronics 136 include a power
supply 208, such as a battery, to provide electrical power to the
electrics as well as to the motor 202 in the bearing release
mechanism 130. A controller 210 performs the described functions as
well as facilitating the overall operation of the braking apparatus
100. For the examples described herein, the controller 210
comprises a processor with a memory and other supporting circuits.
The controller 210, however, may be any combination of electrical
devices that can perform the described tasks. For example, the
controller 210 may include logical devices in some circumstances. A
receiver 212 is configured to receive wireless signals 138 through
an antenna 214. The wireless signals 138 are typically transmitted
by a transmitter 216 through a transmitting antenna 218. As
mentioned above, the transmitting antenna 218 may be a wire loop
embedded in the floor near and exit of a store where the braking
apparatus 100 is implemented as part of caster of a shopping cart.
The wireless signals 138 may also be transmitted by handheld
devices or other transmitters, depending on the particular
implementation and requirements. In the exemplary embodiment, the
receiver 212 can receive signals within two frequency bands and the
antenna 214 is comprised of two antennas. Low frequency signals
that have relatively short propagation distances are received
through an inductor and higher frequency signals having longer
propagation distances are received through an antenna formed with a
conductive trace on a printed circuit board. In implementations
where the braking apparatus is used on a shopping cart, the lower
frequency signals are typically used for transmission when the
braking apparatus 100 is at particular locations and are emitted
from wire loops in the floor near the exit of store. The higher
frequency signals in such an implementation are typically
transmitted by hand held devices or from transmitters that are
intended to control the braking apparatus 100 from a greater
distance. Examples of suitable frequencies for the wireless signals
includes frequencies in the 2.4 GHz band as defined by the IEEE
802.11 set of standards and 8 KHz electromagnetic signal emitted by
a buried wire to establish a magnetic field at perimeters to a
monitored area.
[0062] Although other techniques can be used, the bearing release
mechanism 130 includes an electric motor 202 and a threaded block
204 where rotation of the motor in one direction extends the
threaded block to a position that does not allow the ball bearing
to enter the bearing channel. As explained above, counter rotation
of the motor in the opposite direction retracts the threaded block
204 to a position that allows the ball bearing to enter the bearing
channel. Block position sensors 220 provide the controller 210 with
information regarding the position of the threaded block 204. The
controller 210 uses the information to control the motor 202 to
stop rotation when the threaded block 204 has reached the
predetermined positions and to reset the bearing release mechanism
130. For example, signals from the block position sensors 220
indicate when the motor 202 has reached the fully extended position
and the fully retracted position so that the controller can
withdraw power from the motor. The block position sensors 220 also
allow the controller 210 to be aware of the threaded block position
after an interruption of operation, such as when a battery is
replaced. Switches can be used to form the block position sensors
where the position of the threaded block determines whether a
particular switch is open or closed. An example of suitable
implementation of the block position sensors 220 includes forming
switches between features on the threaded block 204 and contacts on
the PCB 206. Although the block sensors may only act as limit
switches and provide information corresponding to whether the
threaded block is fully extended or retracted, some implementations
may provide information indicating positions between the two
extremes. For example, several block position sensors may allow the
controller 210 to determine the position of the block based on the
state of the sensors.
[0063] In the exemplary embodiment, the motor 202 and the block
position sensors 220 are mounted on the PCB 206. In some
circumstances, however one or both of these components are not
mounted on the PCB 206. For example, the motor 202 may be connected
to the non-rotating housing in some situations.
[0064] FIG. 3 is an illustration of a perspective view of a caster
assembly 300 including the braking apparatus 100 connected to the
wheel 102 and mounted on a yoke 302 in accordance with the
exemplary embodiment of the invention. In a typical implementation,
the caster assembly 300 is mounted on a vehicle such as a shopping
cart or dolly. The illustration of FIG. 3 is in accordance with the
first and second exemplary embodiments.
[0065] In the exemplary embodiments discussed herein, the
non-rotating component 112 is a non-rotating housing 304 made of
plastic. The non-rotating housing 304 is held in place by the yoke
302 and an axle bolt 306 that passes through the wheel bearing 108.
A portion of the non-rotating housing 304 fits within the wheel hub
106. An outer portion 308 of the non-rotating housing 304 includes
a yoke recess 310 for accepting one arm 312 of the yoke 302. The
non-rotating housing 304 is held in place by the yoke arm 312 and
cannot rotate relative to the yoke 302.
[0066] When the braking apparatus 100 is in the non-braking state
(freewheeling state), the wheel 102 can rotate in either direction
109, 125 and the vehicle can be moved in either the forward
direction 314 or the reverse direction 316. When the caster
assembly 300 moves forward 314, the wheel 102 rotates with forward
rotation and when the wheel moves in reverse 316, the wheel rotates
with reverse rotation 125. In FIG. 3, forward rotation 109 is
counter-clockwise and reverse rotation 125 is clockwise.
[0067] FIG. 4A is an illustration of a top view of a PCB assembly
400 and FIG. 4B is an illustration of a side view of PCB assembly
400. Some of the components are omitted in the view of FIG. 4B for
clarity. In the exemplary embodiments, the electronics 136 and the
electrical motor 202 are mounted on the PCB 206.
[0068] The motor 202 is connected to the threaded block 204 by a
threaded shaft (screw shaft) 401. As the motor 202 is activated,
the threaded shaft 401 rotates within the threaded block 204 to
move the threaded block between the retracted position and the
extended position.
[0069] The PCB 206 has a hole 402 to allow assembly within the
caster assembly 300. The electronics 136 may include any
combination of ICs 404, ASICs 406, electrical components, wires
408, and conductive traces 410. The electrical components may
include transistors 412, resistors 414, capacitors 416, inductors
418, and other devices where the electrical components may be
discrete devices, integrated as part of single package including
several components, or may be at least partially formed by
conductive traces on the PCB 206. One or more of the types of
components discussed may not be used some circumstances. The PCB
206 may include any number of dielectric layers and conductive
traces 410 where traces 410 and layers may be connected through
vias 420 through the PCB.
[0070] In the exemplary embodiments, the block position sensors 422
are soldered to the PCB 206 and are positioned adjacent to the
threaded block 204. The block position sensors 422 are switches
used to designate limits of travel in the exemplary embodiment that
indicate a position of the threaded block 204 to the controller
210. Although discrete devices can be soldered or otherwise
attached to the PCB 206 in some implementations, the block position
sensors 420 may be implemented using conductive pads on the PCB and
contacts on the threaded block.
[0071] As explained above, the antenna 214 includes two antennas in
the exemplary embodiment. A low frequency antenna 424 is
implemented with an iron core inductor 424 and a conductive trace
426 on the PCB 206 forms the high frequency antenna 426. The
antenna 214 may be a discrete component, wire, or other device in
some circumstances. The various patterns, objects, and blocks shown
in FIG. 4A are intended to generally represent the electronics 136
and do not necessarily represent any particular electrical
circuit.
[0072] In some circumstances, the PCB 206 includes an alignment
feature 428 that facilitates appropriate alignment between the PCB
206 and the non-rotating housing 304. An example of a suitable
feature includes a notch in the PCB 206 that is aligned with a tab
of the non-rotating housing 304.
[0073] FIG. 5A and FIG. 5B are illustrations of exploded views of
the wheel 102 and braking apparatus 100 in accordance with the
first exemplary embodiments where the ball bearing 114 is at least
partially moved by gravity to the braking position. For reference,
the arrow (109) indicates the forward wheel rotation 109. The outer
portion 502 of the non-rotating housing 304 includes the yoke
recess 310 to engage the yoke and the inner portion 504 of the
non-rotating housing includes features that at least partially form
the bearing channel 134. The electric motor 202 and electronics 136
are mounted on a circular printed circuit board 206 which fits
within and aligns within the non-rotating housing 304 such that the
threaded block 204 is aligned at the opening 140 to the bearing
channel 134. In the exemplary embodiment, a tab 506 on inner
portion 504 of the non-rotating housing 304 fits within the notch
424 in the PCB 206 to align the components. When assembled, the
wheel bearing 108 of the wheel hub 106 fits within the hole 402
within PCB 206 and an opening within the hub interface component
110.
[0074] The hub interface component 110 fits within the wheel hub
106 such that protruding features 508 on the inner surface 510 of
the wheel hub 106 engage recesses 512 on the outer surface 514 of
the hub interface component 110. The hub interface component 110 is
discussed in further detail below with reference to FIG. 8A, FIG.
8B, and FIG. 8C.
[0075] A bearing deflector 516 diverts the ball bearing 114 from
entering the opening 140 when the wheel 102 is rotated forward 109
while the braking apparatus is in the braking configuration. The
bearing deflector 516 is section of spring steel connected to the
non-rotating housing 304 in the exemplary embodiment. The angle of
the spring steel section is selected to divert the bearing over the
opening 140 when the wheel is rotated and the ball bearing 114 is
in a bearing groove 116. When the wheel is rotated in reverse 125,
however, the ball bearing 114 can fall into the opening 140.
[0076] The bearing channel 134 is formed by portions of the
non-rotating housing 304 and the PCB 206 in the example embodiment.
Features 518 form three sides of the rectangular channel and an
adjacent portion of the PCB 206 forms the fourth side. The bearing
channel 134, however, may be formed in different ways. For example,
the entire bearing channel may be formed within the non-rotating
housing 304. Such a configuration may be desired in implementations
where restricting contact of the ball bearing 114 with the PCB 206
is desired or where the PCB 206 does not extend to the region
adjacent to the bearing channel features 518 in the non-rotating
housing 304.
[0077] FIG. 6A is an illustration of a side view of the inner
portion 504 of the non-rotating component housing 304. FIG. 6B is
an illustration of a side view of the outer portion 502 of the
non-rotating component housing 304. FIG. 6C is an illustration of a
top view of the non-rotating component housing at line A-A of FIG.
6B. FIG. 6A, FIG. 6B, and FIG. 6C are illustrations in accordance
with the first exemplary embodiments. In the first and second
exemplary embodiments, the non-rotating housing 304 is a single
unit made of molded plastic such as shatter resistant
Polypropylene, Polyethylene, Acrylonitrile Butadiene Styrene (ABS).
The bearing channel is formed by plastic walls 518 that extend from
the opening, to the bearing release mechanism, to the bearing port
with a section configured to allow the threaded block to move
through the bearing channel. The bearing wall 118 is part of the
non-rotating housing 304 in the example. The non-rotating housing
304 can be formed using other techniques and may include multiple
parts made from different materials. For example, in addition to
the bearing deflector 501, the bearing wall and bearing channel may
be formed from different materials and attached to the non-rotating
housing 304 in some circumstances.
[0078] The non-rotating housing 304 has a bearing guide flange 602.
When the braking assembly is assembled, an edge of the hub
interface component 110 rotates against the bearing guide flange
602. When the ball bearing 114 is one of the bearing grooves 116,
therefore, the bearing guide flange 602 encloses the ball bearing
114 between the hub interface component 110 and the bearing guide
flange 602.
[0079] FIG. 7A is an illustration of a perspective view of the
braking assembly 700 including the hub interface component, the PCB
assembly 400, the ball bearing 114, and the non-rotating housing
304. FIG. 7B is an illustration of a side view of the braking
assembly 700. In the interest of clarity, some details of the
interior of the assembly 100 are omitted in FIG. 7A. FIG. 7B is an
illustration of a side view of the braking assembly 700.
[0080] After the braking assembly 700 is assembled, the ball
bearing 114 and PCB assembly 400 are sealed between the hub
interface component 110 and the non-rotating housing 304. The edge
702 of hub interface component 110 slides against the bearing guide
flange 602 when the hub interface component 110 rotates relative to
the non-rotating housing 304. In the non-braking configuration, the
ball bearing 114 is positioned between the PCB 206 and the
non-rotating housing 304. When the breaking apparatus is in the
braking configuration and the ball bearing 114 has been released
through the bearing channel 134, the ball bearing 114 falls into a
bearing groove 116. As the hub interface component 110 is rotated,
the ball bearing slides or rolls against the bearing guide flange
602 until it is interposed between one of the bearing barriers and
the one of the side of the bearing wall 118.
[0081] FIG. 8A through FIG. 8E are illustrations in accordance with
the first exemplary embodiments and, therefore, illustrate the
movement of the components for the examples where the movement of
the ball bearing 114 to the braking position is at least partially
due to gravity. FIG. 8A is an illustration of a cross sectional
side view of the braking assembly 700 taken along line B-B of FIG.
7B when the braking apparatus 100 is in the braking configuration
and the ball bearing 114 is in a forward braking position. When the
braking apparatus 100 is in the braking configuration, the threaded
block 204 is moved by the motor 202 to the retracted position.
Rotating the threaded shaft within the threaded block 204 moves the
threaded block 204 away from the bearing channel 134 allowing the
ball bearing 114 to fall through the bearing channel 134 into one
of the bearing grooves 116. Depending on the rotation of the wheel
102, the ball bearing 114 eventually becomes interposed in either
the forward braking position or the reverse braking position. The
ball bearing 114 is shown in the forward breaking position in FIG.
7A which results when the wheel 102 is rotated in the forward
direction 109. The ball bearing 114 contacts a first bearing
barrier 120 of one of the bearing groves 116 and the first bearing
wall 124 of the non-rotating component. In this position, the hub
interface component 110 cannot be rotated relative to the
non-rotating component 112 (non-rotating housing 304) in the
forward direction 109. As a result, the wheel 102 cannot be rotated
forward. As discussed below, if the wheel 102 is rotated in reverse
125, the ball bearing 125 eventually becomes interposed in the
reverse braking position between the second bearing wall 126 and
the second bearing barrier 122 of one of the bearing grooves 116.
The wheel 102 cannot be rotated in the reverse direction 125 when
the ball bearing 114 is in the reverse braking position. In the
exemplary embodiment, the clutch mechanism allows the wheel 102 to
rotate when a torque threshold exceeded. Accordingly, if force is
applied to move the vehicle when the braking apparatus 100 is in
the braking configuration, the wheel 102 will only rotate when the
force exceeds the force corresponding to the threshold torque.
[0082] FIG. 8B is an illustration of a cross sectional side view of
the braking assembly 700 taken along line B-B of FIG. 7B when the
braking apparatus 100 is in the non-braking configuration and the
ball bearing 114 is contained in the bearing release mechanism 134.
In the non-braking configuration, the wheel 102 can rotate freely
in either direction.
[0083] FIG. 8C is an illustration of a cross sectional side view of
the braking assembly 700 taken along line B-B of FIG. 7B when the
braking apparatus 100 is in the braking configuration and the ball
bearing 114 is released into the bearing channel 134. In the
exemplary embodiment, the electric motor 202 is activated and the
threaded block 204 is moved to a position that allows the ball
bearing 114 to fall through the bearing channel 134. Accordingly,
gravity moves the ball bearing 114 to the bearing groove 116 after
the ball bearing 114 is released. In FIG. 8C, the ball bearing 114
is shown just prior to be expelled through the bearing port 132 of
the bearing channel 134.
[0084] FIG. 8D is an illustration of a cross sectional side view of
the braking assembly 700 taken along line B-B of FIG. 7B when the
braking apparatus 100 is in the braking configuration and the ball
bearing is within one of the bearing grooves 116 while the wheel
102 is rotated in the forward direction 109. As the wheel 102 is
rotated forward, the ball bearing 114 slides and/or rolls against
the bearing guide flange 602 as the bearing groove 116 rotates. The
bearing deflector 516 causes the ball bearing 114 to "jump" the
opening 140 to the bearing channel. The bearing deflector 516 has a
configuration such that the ball bearing cannot fall into the
bearing channel when the wheel is rotated forward 109. The ball
bearing 114 continues along the circular path 802 until it is
trapped between the bearing barrier 120 and the first bearing wall
124 as shown in FIG. 8A.
[0085] FIG. 8E is an illustration of a cross sectional side view of
the braking assembly 700 taken along line B-B of FIG. 7B when the
braking apparatus 100 is in the braking configuration and the ball
bearing 114 is within one of the bearing grooves 116 while the
wheel is rotated in the reverse direction 125. When the ball
bearing 114 is in the forward braking position as shown in FIG. 8A
and the wheel 102 is rotated in reverse 125, the ball bearing 114
falls through the bearing channel 134 into a bearing groove 116. As
the wheel is rotated, the ball bearing 114 is carried within the
bearing groove 116 until it becomes interposed between the second
bearing wall 126 and the second bearing barrier 122.
[0086] FIG. 9A, FIG. 9B, and FIG. 9C are illustrations of an
example of clutch mechanism formed by the hub interface component
110 and the wheel hub 106. FIG. 9A is an illustration of the hub
interface component 110 in an example where the hub interface
component 110 forms a clutch mechanism with features of the wheel
hub 106 when installed in the wheel hub 106. FIG. 9A is an
illustration of a side view of an inner portion of the hub
interface component 110. FIG. 9B is an illustration of a side view
of the side of the wheel hub for engaging the hub interface
component. FIG. 9C is an illustration of the hub interface
component 110 inserted into the wheel hub 106 to form the clutch
mechanism.
[0087] In the exemplary embodiment, the hub interface component 110
is a circular, concave unit that fits within the wheel hub 106 such
that an outer surface 514 of the hub interface component 110
engages an inner surface 510 of the wheel hub 106. The wheel
bearing in the wheel hub fits within an opening within the hub
interface component 110.
[0088] For this example, the hub interface component 110 includes
six bearing grooves 116 separated by non-grooved portions of the
hub interface component 110. The hub interface component 110 has a
size and shape that allows the outer surface 514 of the hub
interface component to interface to, or otherwise engage, the inner
surface 510 of the wheel hub 106. As explained above, in some
circumstances, the clutch mechanism may be omitted and the hub
interface component 110 is securely fastened to the wheel hub. In
this example, however, the outer surface 510 of the hub interface
component includes a plurality of indentations or recesses 506 that
engage protruding features 508 on the inner surface 510 of the
wheel hub. The number of indentations 506 and the spacing between
indentations 506 depends on the particular implementation. An
example of suitable configuration includes 30 to 50 indentations
that are equally spaced. The number and dimensions of indentations,
as well as the spacing between indentations, are selected to
provide a desired resistance to rotation relative to the wheel hub
when the hub interface component is held in the braking position
and a force is applied to the wheel. The characteristics of the
indentations are also related to the materials used for the wheel
hub, protruding features, and the hub interface component as well
as the number of protruding features of the wheel hub. Although
FIG. 9B and FIG. 9C show six protruding features 508, any number
may be used as long as the desired resistance to rotation is
achieved.
[0089] An example of suitable implementation of the protruding
features 508 includes inserting dowels into holes drilled into the
wheel hub. The dowels may be made from any of several materials
providing at least the appropriate flexibility, strength,
durability, and friction. Examples of suitable materials include
aluminum, steel, nylon, high density plastics. In some
circumstances, the protruding features may be part of the wheel hub
and may be formed when the wheel hub is formed. For example, the
wheel hub may formed by an injection mold process where the mold
includes recesses to form the protruding features 508.
[0090] The clutch mechanism may be implemented in different ways.
In some circumstances, for example, the outer surface of the hub
interface component includes the protruding features and the inner
surface of the wheel hub includes the indentations. In other
circumstances, the indentations and protruding features are omitted
and the hub interface component and the wheel hub have shapes and
sizes such that a force fit is formed between the hub interface
component and the wheel hub to provide adequate friction between
the two components to restriction rotation between the two
components until the torque threshold is reached.
[0091] FIG. 10 is an illustration of an exploded view of the wheel
102 and braking apparatus 100 in accordance with the second
exemplary embodiment where the ball bearing is at least partially
moved by magnetic force to the non-braking position. For reference,
the arrow (109) indicates the forward wheel rotation 109. The
exterior of the non-rotating housing 304 for this example is as
described with reference to FIG. 3, FIG. 5A, and FIG. 5B. The outer
portion 502 of the non-rotating housing 304, therefore, includes
the yoke recess 310 to engage the yoke and the inner portion 504 of
the non-rotating housing includes features that at least partially
form the bearing channel 134. The electric motor 202 and
electronics 136 are mounted on a circular printed circuit board 206
which fits within and aligns within the non-rotating housing 304
such that the threaded block 204 is aligned at the opening 140 to
the bearing channel 134. The tab 506 on inner portion 504 of the
non-rotating housing 304 fits within the notch 424 in the PCB 206
to align the components. When assembled, the wheel bearing 108 of
the wheel hub 106 fits within the hole 402 within PCB 206 and an
opening within the hub interface component 110.
[0092] The hub interface component 110 fits within the wheel hub
106 such that protruding features 508 on the inner surface 510 of
the wheel hub 106 engage recesses 512 on the outer surface 514 of
the hub interface component 110. The hub interface component 110 is
discussed in further detail below with reference to FIG. 11.
[0093] The bearing channel 134 is formed by portions of the
non-rotating housing 304 and the PCB 206 in the example embodiment.
Features 518 form three sides of the rectangular channel and an
adjacent portion of the PCB 206 forms the fourth side. The bearing
channel 134, however, may be formed in different ways. For example,
the entire bearing channel may be formed within the non-rotating
housing 304. Such a configuration may be desired in implementations
where restricting contact of the ball bearing 114 with the PCB 206
is desired or where the PCB 206 does not extend to the region
adjacent to the bearing channel features 518 in the non-rotating
housing 304.
[0094] The bearing channel 134 in this example extends laterally
and perpendicular to the direction of gravity. The bearing wall 118
differs from the example of FIG. 5B in that the bearing wall sides
124, 126 in this example are closer to each other and are
positioned at the opening 140 to the bearing channel such that the
bearing channel 134 is positioned in between the two bearing wall
sides 124, 126. The threaded block travels within the three sides
of the bearing channel 134 formed by the non-rotating component
housing and the PCB 206. For this example, gravity does not move
the ball bearing 114 from the non-braking position to the braking
position and the ball bearing is moved to a region between the two
sides 124, 126 of the bearing wall 118 when the thread block is
extended. Although the ball bearing 114 is magnetic in the second
exemplary embodiments, the threaded block or other components may
be magnetic in some situations.
[0095] FIG. 11 is an illustration of a side view of the inner
portion 504 of the non-rotating component housing 304 for the
example where the ball bearing is moved to the non-braking position
with magnetic force. As discussed above, the non-rotating housing
304 is a single unit made of molded plastic such as shatter
resistant Polypropylene, Polyethylene, Acrylonitrile Butadiene
Styrene (ABS) in the exemplary embodiments. The bearing channel is
formed by plastic walls 518 that extend from the opening 140 to the
bearing release mechanism and includes a section configured to
allow the threaded block to move through the bearing channel. The
bearing wall 118 is part of the non-rotating housing 304 in the
example. The non-rotating housing 304 can be formed using other
techniques and may include multiple parts made from different
materials.
[0096] The non-rotating housing 304 has a bearing guide flange 602
as in the example discussed with reference to FIG. 6A. When the
braking assembly is assembled, an edge of the hub interface
component 110 rotates against the bearing guide flange 602. When
the ball bearing 114 is one of the bearing grooves 116, therefore,
the bearing guide flange 602 encloses the ball bearing 114 between
the hub interface component 110 and the bearing guide flange
602.
[0097] FIG. 12 is an illustration of a side view of the hub
interface component 110 where the hub interface component 110
includes three bearing grooves 116. For the examples where magnetic
force is used to move the ball bearing 114, the hub interface
component 110 includes three bearing grooves 116. As described
above, the number and size of the bearing grooves depends on the
particular implementation. A larger number of bearing grooves
results in less travel distance between forward and reverse locking
positions of the wheel. Larger numbers of bearing grooves also
results in greater likelihood that a feature of the hub interface
component 110 other than the bearing groove will interfere with the
ball bearing when the threaded block is extended in the breaking
configuration.
[0098] FIG. 13A and FIG. 13B are illustrations in accordance with
the second exemplary embodiments and, therefore, illustrate the
movement of the components for the examples where the movement of
the ball bearing 114 to the non-braking position is at least
partially due to magnetic force. FIG. 13A is an illustration of a
cross sectional side view of the braking assembly 700 taken along
line B-B of FIG. 7B when the braking apparatus 100 is in the
non-braking configuration. In accordance with the second exemplary
embodiments, the ball bearing 114 is magnetic and the threaded
block includes at least a portion that is made from a magnetically
attractive material such as stainless steel. The threaded block may
be made from other ferrous metal alloys. In some circumstances, the
material of the threaded block may not be magnetically attractive
and magnetically attractive material is, connected to, injected
into, inserted into, or otherwise attached to the threaded block.
For example, the threaded block may be made from a plastic such as
Delrin.RTM. available from DuPont.TM.. Such a material has several
desirable properties such as a relatively high hardness and low
coefficient of friction. Since the material is not magnetically
attractive, however, a ferrous metal feature can be embedded or
connected to the threaded block. In the non-braking configuration,
the threaded block is in the retracted position and the ball
bearing 114 is in contact with the threaded block. The magnetic
force between the ball bearing and the threaded block maintains the
ball bearing in contact with the threaded block and does not allow
the ball bearing to travel to the region between a bearing groove
and the sides 124, 126 of the bearing wall. The hub interface
component rotates freely relative to the non-rotating component
(non-rotating housing).
[0099] FIG. 13B is an illustration of a cross sectional side view
of the braking assembly 700 taken along line B-B of FIG. 7B when
the braking apparatus 100 is entering the braking configuration and
the threaded block is in the extended position. The threaded block
204 is moved by the motor 202 to the extended position. Rotating
the threaded shaft within the threaded block 204 moves the threaded
block 204 through the bearing channel 134 pushing the ball bearing
114 through the bearing channel 134 into one of the bearing grooves
116. Depending on the rotation of the wheel 102, the ball bearing
114 eventually becomes interposed in either the forward braking
position or the reverse braking position. The ball bearing 114 is
shown in a position prior to one of the bearing barriers 120, 122
of the bearing groove 116 engaging the ball bearing 114. As the
wheel is rotated, the hub interface component rotates and one of
the sides (120, 123) of one of the bearing grooves 116 contacts the
ball bearing 114. The ball bearing is pulled from the threaded
block as the hub interface component continues to rotate since the
force of the hub interface component exceeds the magnetic force
between the threaded block and the ball bearing 114. The hub
interface component continues to rotate until the ball bearing is
interposed between a bearing barrier (bearing groove side) and a
side 122, 124 of the bearing wall 118. The threaded block remains
extended in the braking configuration. If the wheel is rotated in
the opposite direction, the ball bearing is interposed between the
other side of the bearing groove the other side of bearing wall
118.
[0100] FIG. 14 is a flow chart of a method of inhibiting rotation
of a rotating component in accordance with the first exemplary
embodiments. The method may be performed with any of numerous
devices having structures in accordance with the structures
described above.
[0101] At step 1402, a wireless signal is received. The receiver
212 receives the wireless signal through the antenna 214. In the
exemplary embodiment, if the signal is a low frequency signal such
as 8 KHz signal, the wireless signal is received through an iron
core inductor 424 and if the wireless signal is a higher frequency
signal such as a 2.4 GHz signal, the wireless signal is received
through a conductive trace antenna 426.
[0102] At step 1404, the moveable interposer is moved where the
movement is at least partially caused by gravity. The moveable
interposer is moved to the braking position between the
non-rotating component feature of the non-rotating component and
the rotating component feature of the rotating component to inhibit
rotation of the rotating component relative to the non-rotating
component. Although the moveable interposer may be moved in
response to other events, the braking is invoked in response to
receipt of the wireless signal in exemplary embodiment. For the
example discussed herein, the moveable interposer is a ball
bearing, the rotating component feature is a bearing groove, and
the non-rotating component feature is a bearing wall. The ball
bearing is released from a non-braking position to allow the ball
bearing to travel to the bearing groove and be moved within the
bearing groove by rotation of the rotating component until the ball
bearing is interposed between a wall of the bearing groove and the
bearing wall. The movement of the ball bearing is at least
partially caused by rotation of the rotating component in this
example. The bearing can be released using any of several
techniques. In the exemplary embodiment, an electrical motor is
activated to move a threaded block which allows the call bearing to
fall through a bearing channel to the bearing groove. Therefore,
the moveable interposer is moved at least partially by an actuator.
Other mechanical actuators can be used such as solenoids, magnets,
rotating springs, scissor arms, and springs, for example.
[0103] FIG. 15 is a flow chart of a method of inhibiting rotation
of a rotating component in accordance with the second exemplary
embodiments. The method may be performed with any of numerous
devices having structures in accordance with the structures
described above.
[0104] At step 1502, a wireless signal is received. The receiver
212 receives the wireless signal through the antenna 214. In the
exemplary embodiment, if the signal is a low frequency signal such
as 8 KHz signal, the wireless signal is received through an iron
core inductor 424 and if the wireless signal is a higher frequency
signal such as a 2.4 GHz signal, the wireless signal is received
through a conductive trace antenna 426. The wireless signal
indicates to the controller that the braking apparatus should be
placed in the braking configuration.
[0105] At step 1504, the moveable interposer is moved to a braking
position between a non-rotating component feature of a non-rotating
component and a rotating component feature of a rotating component
to inhibit rotation of the rotating component relative to the
non-rotating component. In accordance with the second exemplary
embodiments, a mechanical actuator 142 such as threaded block
connected to an electric motor is activated in response to the
wireless signal and pushes the magnetic ball bearing 114 through
the bearing channel 134 to a position where bearing groove 116 can
break the magnetic bond between the ball bearing and the mechanical
actuator. The side of the bearing groove moves the ball bearing
until the ball bearing is interposed between the side of the
bearing groove and the bearing wall of the non-rotating component.
Once the ball bearing is lodged between the bearing groove and the
bearing wall, the rotating component cannot rotate relative to the
non-rotating component.
[0106] At step 1506, another wireless signal is received. The
receiver 212 receives the wireless signal through the antenna 214.
In the exemplary embodiments, if the signal is a low frequency
signal such as 8 KHz signal, the wireless signal is received
through an iron core inductor 424 and if the wireless signal is a
higher frequency signal such as a 2.4 GHz signal, the wireless
signal is received through a conductive trace antenna 426. The
wireless signal indicates to the controller that the braking
apparatus should be placed in the non-braking configuration.
[0107] At step 1508, the moveable interposer is moved from the
braking position to a non-braking position. In the non-braking
position, the moveable interposer does not inhibit rotation of the
rotating component relative to the non-rotating component. In
accordance with the second exemplary embodiments, the movement of
the moveable interposer from the braking position to the
non-braking position is at least partially due to magnetic force.
In accordance with the second exemplary embodiments, the moveable
interposer is moved to the non-braking position by moving the
mechanical actuator that is magnetically attractive to the moveable
interposer. In response to the other wireless signal, the
controller 210 actives the electric motor 202 to move the threaded
block 204 to the recessed position. The threaded block is either
made from a magnetically attractive material or includes a
magnetically attractive component 144. The magnetic ball bearing is
attracted to the threaded block 204 and moves to a position outside
of the bearing groove 116 allowing rotating component to rotate
relative to the non-rotating component. The ball bearing 114,
therefore, is pulled by magnetic force from the region between the
bearing wall and the side of the bearing groove.
[0108] Clearly, other embodiments and modifications of this
invention will occur readily to those of ordinary skill in the art
in view of these teachings. The above description is illustrative
and not restrictive. This invention is to be limited only by the
following claims, which include all such embodiments and
modifications when viewed in conjunction with the above
specification and accompanying drawings. The scope of the invention
should, therefore, be determined not with reference to the above
description, but instead should be determined with reference to the
appended claims along with their full scope of equivalents.
* * * * *