U.S. patent application number 11/533605 was filed with the patent office on 2007-03-22 for notch-finding mechanism and method of using the same.
This patent application is currently assigned to ZIH Corp.. Invention is credited to James William Engel, Thomas Michael Zevin.
Application Number | 20070063092 11/533605 |
Document ID | / |
Family ID | 37883117 |
Filed Date | 2007-03-22 |
United States Patent
Application |
20070063092 |
Kind Code |
A1 |
Zevin; Thomas Michael ; et
al. |
March 22, 2007 |
NOTCH-FINDING MECHANISM AND METHOD OF USING THE SAME
Abstract
One embodiment of the invention is a notch finding mechanism
that at least partially supports and drives a core carrying printer
media. The notch finding mechanism includes a notch finding spring
and a plurality of support posts that extend from a support disk.
The notch finding spring includes a plurality of fingers
constructed of a flexible sheet material, and the fingers are
positioned circumferentially and adjacent each other to define a
plurality of spaces between the fingers. In addition, the fingers
are biased radially outwardly, and each of the fingers has a free
end that has a width that is approximately matched to a width of a
notch in an end of the core. The bias of one of the fingers urges
the free end of the finger into the notch aligned with the finger
when the core is placed over the fingers and is rotated a small
amount.
Inventors: |
Zevin; Thomas Michael;
(Valencia, CA) ; Engel; James William; (Simi
Valley, CA) |
Correspondence
Address: |
ALSTON & BIRD LLP
BANK OF AMERICA PLAZA
101 SOUTH TRYON STREET, SUITE 4000
CHARLOTTE
NC
28280-4000
US
|
Assignee: |
ZIH Corp.
|
Family ID: |
37883117 |
Appl. No.: |
11/533605 |
Filed: |
September 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60719411 |
Sep 21, 2005 |
|
|
|
Current U.S.
Class: |
242/571.5 ;
242/596.7 |
Current CPC
Class: |
B65H 16/06 20130101;
B65H 2801/36 20130101; B65H 2801/12 20130101; B65H 75/185 20130101;
B65H 2301/41369 20130101; B65H 19/126 20130101; B65H 75/30
20130101 |
Class at
Publication: |
242/571.5 ;
242/596.7 |
International
Class: |
B65H 16/06 20060101
B65H016/06 |
Claims
1. A notch finding mechanism for at least partially supporting and
driving a core of a printer media supply, said core defining at
least one notch at an end of the core, the notch finding mechanism
comprising: a drive shaft; and a notch finding spring driven by the
drive shaft, said notch finding spring comprising: a plurality of
fingers positioned circumferentially about a central axis and
adjacent to each other; each of said fingers being biased in a
radially outward direction; each of said fingers having a free end;
wherein the bias of one of the fingers urges the free end of said
finger into the notch defined in the end of the core when the core
is placed over the plurality of fingers and rotated.
2. A notch finding mechanism of claim 1, wherein each of the
plurality of fingers is constructed of a flexible sheet
material.
3. A notch finding mechanism of claim 2, wherein the fingers define
a plurality of spaces therebetween.
4. A notch finding mechanism of claim 3, wherein said free end of
each of the fingers has a width approximately matched to a width of
the notch defined at the end of the supply core.
5. A notch finding mechanism of claim 4, further comprising a
support disk supporting the plurality of fingers.
6. A notch finding mechanism of claim 5, further comprising a
plurality of support posts extending in the axial direction from a
surface of the support disk, each of said plurality of support
posts extending into a respective one of said plurality of spaces
defined between said fingers.
7. A notch finding mechanism of claim 6, further comprising a
frictional clutch positioned between the support disk and a drive
disk connected to the drive shaft.
8. A method of supporting and driving a core of a printer media
supply, the method comprising: positioning the core over a notch
finding spring having a plurality of fingers with a radially
outward bias; and rotating the core and the notch finding spring
relative to each other a small amount until one of the fingers
biases into a notch defined in the core.
9. A method of claim 8, wherein the small amount is 30.degree. or
less.
10. A notch finding spring for driving a core, said core defining
at least one notch adjacent to an end of the core, the notch
finding spring comprising: a plurality of fingers; said fingers
positioned circumferentially about a central axis and adjacent to
each other; each of said fingers being biased in a radial
direction; each of said fingers having a free end, said free end
comprising an engaging portion; wherein the bias of one of the
fingers urges the engaging portion into the notch when the core is
placed adjacent to the plurality of fingers and rotated.
11. A notch finding spring of claim 10 wherein the fingers are
biased in a radially inward direction.
12. A notch finding spring of claim 10 wherein the engaging portion
is at an end of the free end of each finger.
13. A notch finding spring of claim 10 wherein the engaging portion
is adjacent an end of the free end of each finger.
14. A notch finding spring of claim 10 wherein the engaging portion
is a protrusion extending in a radial direction from each finger,
said protrusion adapted for engaging the notch in the core.
15. A notch finding spring of claim 10 wherein the engaging portion
comprises a first arcuate shape having a first diameter and the
notch comprises a second arcuate shape having a second diameter,
the first diameter being slightly smaller than the second diameter,
and wherein the engaging portion is adapted to disengage the notch
when a torque at the engaging portion exceeds a predetermined
amount.
16. A notch finding spring of claim 10 wherein the fingers are
biased in a radially outward direction.
17. A notch finding spring of claim 16, wherein each of the
plurality of fingers is constructed of a flexible sheet
material.
18. A notch finding spring of claim 17, wherein each of the
plurality of fingers extends from a fixed end in a first axial
direction.
19. A notch finding spring of claim 18, wherein each of said
fingers has an arcuate-shaped profile, said arcuate-shaped profile
defined by each of said fingers extending in the first direction
from the fixed end and bending in a radially outward direction
through an arc portion to extend in a second axial direction
generally opposite the first axial direction and toward said free
end.
20. A notch finding spring of claim 19, wherein the fingers define
a plurality of spaces therebetween.
21. A notch finding spring of claim 20, wherein said free end of
each of the fingers has a width approximately matched to a width of
the notch defined at the end of the supply core.
22. A notch finding spring of claim 21, wherein a first diameter
around the free ends of the plurality of fingers is greater than an
inside diameter of the supply core and a second diameter around the
arc portions of the plurality of fingers is less than the inside
diameter of the supply core.
23. A notch finding spring of claim 22, wherein each of said
fingers includes a middle portion between said arc portion and said
free end, said middle portion having a width greater than a width
of said free end.
24. A notch finding spring of claim 23, wherein said arc portion of
each of said fingers has a reduced cross section.
25. A notch finding spring of claim 24, wherein said plurality of
spaces at locations between the arc portions are adapted for
aligning with and receiving a plurality of rigid support posts.
26. A notch finding spring for driving a core, said notch finding
spring being secured to the core, the notch finding spring
comprising: a plurality of fingers; said fingers positioned
circumferentially about a central axis and adjacent to each other;
each of said fingers being biased in a radial direction; each of
said fingers having a free end, said free end comprising an
engaging portion; wherein the bias of one of the fingers urges the
engaging portion into a notch defined adjacent to an end of a drive
shaft when the drive shaft is placed adjacent to the plurality of
fingers and relatively rotated a small amount.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional
Application No. 60/719,411, filed Sep. 21, 2005, which is hereby
incorporated herein in its entirety by reference.
FIELD OF INVENTION
[0002] The present invention involves a notch finding mechanism for
coupling a drive assembly to a hollow cylindrical core and, more
particularly, the use of a notch finding mechanism to couple a
printer media roll to a drive assembly.
BACKGROUND OF THE INVENTION
[0003] Hollow cylindrical cores are used in the printing industry
to carry rolls of printer media, such as paper, labels, or ink
ribbon. The cores can be driven to rotate in a forward or backward
direction by coupling a drive assembly to the core. One method of
coupling a drive assembly to a core includes engaging keys on a
drive disk into notches in the end of the core. More specifically,
in the example shown in FIG. 1, the drive disk 10 extends in a
radially outward direction from the drive shaft 12, and extending
past the periphery of the drive disk 10 in a radially outward
direction are the one or more keys 14, or protrusions. In the
example shown in FIGS. 2A and 2B, the hollow cylindrical core 20
includes one or more notches 22 at an end 23 of the core 20 that
extend from an inner diameter 24 of the core 20 towards an outer
diameter 25 of the core 20. To load the core 20 onto the keyed disk
10 described above, an operator rotates the core 20 until the
notches 22 at the end 23 of the core 20 align with the keys 14. The
keys 14 are then engaged into the notches 22 in the core 20,
allowing the transfer of rotation of the shaft 12 to the core
20.
[0004] This loading operation can be cumbersome for the operator,
especially when the core 20 is carrying a large printer media roll.
In addition, the core 20 can slip away from the disk 10, causing
the keys 14 to disengage from the notches 22 and the media to
misfeed and jam the printer.
[0005] Therefore, a need in the art exists for a device that
radially couples a core onto a drive shaft to transmit the
rotational energy from the drive shaft to the core.
BRIEF SUMMARY OF THE INVENTION
[0006] According to various embodiments, a notch finding mechanism
is provided for at least partially supporting and driving a core of
a printer media supply. The core defines at least one notch at an
end of the core, and the notch finding mechanism includes a drive
shaft and a notch finding spring. The notch finding spring is
driven by the drive shaft and includes a plurality of fingers
positioned circumferentially about a central axis and adjacent to
each other. Each finger is biased in a radially outward direction
and has a free end. The bias of the fingers urges the free end of
one of the fingers into the notch defined in the end of the core
when the core is placed over the plurality of fingers and
rotated.
[0007] In another embodiment, a notch finding spring is provided
for at least partially supporting and driving a core of a printer
media supply. The core defines at least one notch at an end of the
core, and the notch finding spring includes a plurality of fingers.
The fingers are positioned circumferentially about a central axis
and adjacent each other, are biased in a radially outward
direction, and each have a free end. The bias of the fingers urges
the free end of one of the fingers into the notch defined in the
end of the core when the core is placed over the plurality of
fingers and rotated.
[0008] According to another embodiment, a method of supporting and
driving a core of a printer media supply is provided. The method
includes the steps of: (1) positioning the core over a notch
finding spring that has a plurality of fingers with a radially
outward bias, and (2) rotating the core and the notch finding
spring relative to each other a small amount until one of the
fingers biases into a notch defined in the core.
[0009] In yet another embodiment, a notch finding spring is
provided for driving a core that defines at least one notch
adjacent to an end of the core. The notch finding spring includes a
plurality of fingers that are positioned circumferentially about a
central axis and adjacent to each other, are biased in a radial
direction, and have a free end. The free end includes an engaging
portion, and the bias of the fingers urges the engaging portion of
one of the fingers into the notch when the core is placed adjacent
to the plurality of fingers and rotated.
[0010] In another embodiment, a notch finding spring is provided
for driving a core. The notch finding spring is secured to the core
and includes a plurality of fingers that are positioned
circumferentially about a central axis and adjacent to each other.
In addition, each finger is biased in a radial direction and
includes a free end, and the free end includes an engaging portion
that, because of the bias of each finger, is urged into a notch
defined adjacent to an end of a drive shaft when the drive shaft is
placed adjacent to the plurality of fingers and relatively rotated
a small amount.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] Having thus described the invention in general terms,
reference will now be made to the accompanying drawings, which are
not necessarily drawn to scale, and wherein:
[0012] FIG. 1 is an end view of a prior art coupling mechanism;
[0013] FIG. 2A is a side view of a hollow cylindrical core having a
notched end;
[0014] FIG. 2B is an end view of the notched end of the hollow
cylindrical core of FIG. 2A;
[0015] FIG. 3 is a plan view of a printer and a notch finding
mechanism according to one embodiment of the invention;
[0016] FIG. 4A is a perspective view of a notch finding mechanism
and clutch assembly according to one embodiment of the
invention;
[0017] FIG. 4B is a side view of the notch finding mechanism and
clutch assembly of FIG. 4A;
[0018] FIG. 5 is an exploded view of the notch finding mechanism
and clutch assembly of FIG. 4A;
[0019] FIG. 6 is a perspective view of the notch finding mechanism
and clutch assembly of FIG. 4A coupled to a hollow cylindrical
core;
[0020] FIG. 7 is a side view of a finger of the notch finding
spring of FIG. 4A;
[0021] FIG. 8 is a perspective view of a core mounted onto the
notch finding mechanism of FIG. 4A;
[0022] FIG. 9 is a top view of the notch finding spring of FIG.
4A;
[0023] FIG. 10 is an exemplary dimensional specification for the
notch finding spring of FIG. 4A;
[0024] FIG. 11 is a partial plan view of a cut detail for the notch
finding spring of FIG. 10;
[0025] FIG. 12 is a cross sectional view of an exemplary
dimensional specification for a finger of the notch finding spring
of FIG. 4A;
[0026] FIG. 13 is a cross sectional view of the notch finding
mechanism and clutch assembly of FIG. 4A;
[0027] FIG. 14 is a perspective view of a notch finding spring
according to another embodiment of the invention;
[0028] FIG. 15 is a perspective view of the notch finding spring of
FIG. 14 coupled with a hollow cylindrical core;
[0029] FIG. 16A is a plan view of an exemplary cut detail for the
notch finding spring of FIG. 14;
[0030] FIG. 16B is a partial plan view of the cut detail of FIG.
16A;
[0031] FIG. 17A is a side view of a notch finding spring according
to another embodiment of the present invention;
[0032] FIG. 17B is a plan view of the notch finding spring of FIG.
17A;
[0033] FIG. 18 is a side view of notch finding spring according to
one embodiment of the invention;
[0034] FIG. 19 is a side view of a notch finding spring according
to one embodiment of the invention;
[0035] FIG. 20 is a side view of a notch finding spring according
to one embodiment of the invention;
[0036] FIG. 21 is a side view of a notch finding spring according
to one embodiment of the invention;
[0037] FIG. 22 is a side view of a notch finding spring according
to one embodiment of the invention;
[0038] FIG. 23 is a side view of a notch finding spring according
to one embodiment of the invention;
[0039] FIG. 24 is a perspective view of a notch finding spring
according to one embodiment of the invention; FIG. 25 is a side
view of a finger of a notch finding spring according to one
embodiment of the invention;
[0040] FIG. 26 is a side view of a finger of a notch finding spring
according to one embodiment of the invention;
[0041] FIG. 27 is a side view of a finger of a notch finding spring
according to one embodiment of the invention;
[0042] FIG. 28 is a side view of a finger of a notch finding spring
according to one embodiment of the invention; and
[0043] FIG. 29 is a side view of a notch finding spring according
to one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0044] Various embodiments of the present invention address one or
more of the above needs and achieve other advantages by providing a
notch finding mechanism for radially coupling the rotation of a
drive shaft to a hollow cylindrical core. For example, certain
embodiments of the notch finding mechanism include a notch finding
spring mounted to an end of the drive shaft and having a plurality
of fingers that are radially outwardly biased so as to seat within
a notch defined in the media supply core with a relatively small
amount of rotation between the spring and the core. This is enabled
by the large number of fingers, such as twelve fingers, that are
circumferentially positioned and configured to insert as a group
into the core. And, in various embodiments, the outward bias of the
fingers allows them to automatically seat in the notch or notches
of the core, enabling single-handed loading of the core without
attention or regard to the relative rotational position between the
drive shaft and the core.
[0045] In one embodiment, the present invention includes a notch
finding spring for at least partially supporting and driving a core
of a printer media supply. The core defines at least one notch at
its end. Included in the notch finding spring are a plurality of
fingers that are circumferentially positioned adjacent to each
other. Further, the fingers are biased in a radially outward
direction, and each of the fingers includes a free end that can
move radially at least a small amount. The bias of at least one of
the fingers urges its free end into the notch defined in the end of
the core when the core is placed over the plurality of fingers and
relatively rotated (i.e., the core is rotated, the spring is
rotated, or both) a small amount, such as 45.degree., 30.degree. or
less.
[0046] In addition, each of the fingers is constructed of a
flexible sheet material. For example, the sheet material fingers
may extend from a fixed end in a first axial direction, allowing
their insertion into the core. Each of the fingers may also have an
arcuate shaped profile that is defined by the fingers extending in
a first direction from the fixed end, bending in a radially outward
direction through an arc portion and extending in a second axial
direction generally opposite the first axial direction toward the
free end.
[0047] In another aspect, each of the fingers has a width matched
approximately to that of the notch for a firm fit. Also, a first
diameter of around the free ends of the fingers is greater than an
inside diameter of the supply core, and a second diameter around
the arc portion is less than the inside diameter of the supply
core. This allows easy placement of the second diameter into the
core and urging of the free ends at the first diameter into the
notch.
[0048] Each of the fingers may have a varying width, being tapered
at the free end for insertion into the notch, thicker at a middle
portion and tapered near the arc portion. The taper near the arc
portion promotes the insertion of several rigid support posts
supported by the drive shaft between the fingers. These support
posts provide torsional stability for the spring and radial support
for reasonable centering of the rotational axis of the core
independently of the flexing of the spring fingers.
[0049] Various embodiments of the present invention provide several
advantages. For example, the notch finding spring maybe easily
manufactured by punching and drawing from a flexible sheet
material, such as stainless steel or beryllium copper. As another
example, the notch finding spring can be used with existing clutch
and drive assemblies by sizing the width of the fingers to
approximately match the width of the notches in existing cores.
Further, the bias of the fingers and spacing of the fingers close
together allows for single-handed loading of the core onto the
notch finding spring without regard to relative rotational
position. In addition, movement of the core in the axial direction
is prevented or restricted as a result of the bias of the fingers
in a radially outward direction against the inner diameter of the
core.
[0050] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all embodiments of the invention are shown. Indeed,
the invention may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout.
[0051] Printer and Drive Assembly
[0052] As shown in FIG. 3, the printer 30 includes a rectangular
housing 31. The housing 31 includes a base 33 and a lid or cover
(not shown). The base 33 has a rectangular shape with a wall
structure that extends upwardly from the base 33 to support and
contain various electronic and mechanical assemblies of the printer
30.
[0053] The base 33 of the housing 31 supports a print head assembly
40, a drive assembly 50, and a clutch assembly 60. The print head
assembly 40 includes a platen roller 41, a print head 42, and media
guide surfaces 43. The print head assembly 40 urges a printer media
80 between the platen roller 41 and the print head 42 to allow the
print head 42 to print on the printer media 80.
[0054] The drive assembly 50 includes a drive motor 51 that rotates
a drive shaft 52. The drive motor can include, for example, a
stepper motor. The drive shaft 52 has a driven end 53 adjacent to
the drive motor 51 and a free end 54 opposite the driven end 53.
The drive shaft 52 further includes a drive disk 55 that extends in
a radially outward direction from the axis of rotation of the drive
shaft 52 and is positioned on the drive shaft 52 near the free end
54. The drive assembly 50 further includes a support pin 56 that is
positioned opposite the drive shaft 52. A non-driven end of the
hollow cylindrical core is rotatably mounted on and vertically
supported by the support pin 56, which may or may not be keyed.
[0055] The clutch assembly 60 engages to transmit the rotational
energy from the drive shaft 52 and disengages when the torque on
the drive shaft 52 at the clutch assembly 60 exceeds a particular
amount. As shown in FIGS. 4A and 4B, the clutch assembly 60
includes the drive disk 55, a support disk 61, and a first, second,
and third intermediate frictional disks 201, 202, 203, which are
shown in FIG. 5. The drive disk 55 is integrally attached to the
drive shaft 52 and extends in a radially outward direction from the
drive shaft 52. The support disk 61 is separate from the drive
shaft 52 and includes a central aperture 63 for receiving the end
54 of the drive shaft 52 and a mounting surface 64 for mounting
adjacent to the drive disk 55. Between the support disk 61 and the
drive disk 55 are the intermediate frictional disks 201, 202, 203
that have frictional material on both sides and frictionally engage
each other to couple the support disk 61 to the drive disk 55 with
a designed "torque versus rotational" slip behavior.
[0056] The first intermediate frictional disk 201 is coupled to the
drive disk 55, and the second intermediate frictional disk 202 is
coupled to the support disk 61. The third intermediate frictional
disk 203 is positioned between the first 201 and second
intermediate frictional disks 202 and frictionally engages the
first 201 and second intermediate frictional disks 202. In one
embodiment, the intermediate frictional disks 201, 202 are made of
cartridge brass, the support disk 61 is made of an unfilled
polycarbonate, and the drive disk 55 and drive shaft 52 are made of
injection molded nylon 6/6.
[0057] To couple the intermediate frictional disks 201, 202 to the
drive disk 55 and the support disk 61, the drive disk 55 and the
support disk 61 include one or more keys 210 that protrude axially
from the mating surfaces of each disk 55, 61 and extend lengthwise
in a radially outward direction from the center of each disk 55,
61, as shown in FIG. 5. The keys are positioned towards the center
of the drive disk 55 and the support disk 61. Each of the
intermediate frictional disks 201, 202 include a central aperture
215 which is adapted for receiving the end of the drive shaft 52,
and one or more notches 216 that extend in a radially outward
direction from the central aperture 215. The notches 216 receive
the keys 210 on the support disk 61 and drive disk 55, which
couples the drive disk 55 to the first intermediate frictional disk
201 and the support disk 61 to the second intermediate frictional
disk 202. The keys 210 and notches 216 are not limited to being
positioned in the center of the disks 201, 202, 55, and 61 and
could be positioned, for example, along the periphery of the disks
201, 202, 55, and 61.
[0058] When the torque on the drive shaft 52 at the clutch assembly
60 is below a particular amount, intermediate frictional disks 201,
202 engage the third intermediate frictional disk 203, and the
rotational energy of the drive shaft 52 is transferred to the
support disk 61. If the torque on the drive shaft 52 at the clutch
assembly 60 exceeds the particular amount, the intermediate
frictional disks 201, 202 disengage from the third intermediate
frictional disk 203, allowing the drive disk 55 to rotate
independently of the support disk 61.
[0059] The printer described above is for illustration purposes
only. It is envisioned that one of skill in the art would
understand that the present invention is suitable for use in a
variety of types of printers, such as thermal head printers,
portable printers, or thermal transfer printers, or even other
driven media or core driven devices, such as film rolls or paper
rolls.
[0060] Notch Finding Mechanism
[0061] A notch finding mechanism 100 of one embodiment of the
present invention couples a hollow cylindrical core carrying
printer media to the drive assembly of a printer. FIGS. 5 and 6
show the notch finding mechanism 100 according to one embodiment
that includes a notch finding spring 101 and the support disk 61
having a plurality of support posts 230. The notch finding spring
101 includes a plurality of arcuate-shaped fingers 102 formed of a
flexible sheet material and a base portion 104.
[0062] Advantageously, the large number of fingers 102 enables a
relatively small rotation (e.g., 45.degree., 30.degree. or less)
between the notch finding spring 101 and the core of the media
supply. For example, the amount of rotation will generally be the
same or less than 360.degree. divided by the number of fingers,
such as 6, 8 or the illustrated twelve fingers 102.
[0063] The fingers 102 have a fixed end 110 and a free end 108, and
the fixed ends 110 of the fingers 102 are integrally attached to
and positioned circumferentially around the base portion 104 and
adjacent to each other, as shown in FIG. 6. A plurality of spaces
106 are defined between the fingers 102, and the spaces 106 allow
the free end 108 of each finger 102 to move in a radial direction
independently of adjacent fingers 102. Furthermore, the free end
108 of each finger 102 has a reduced width w.sub.f compared to the
portion of the finger 102 adjacent to the free end 108. The width
w.sub.f of the free end 108 is approximately matched to the width
w.sub.n of a notch 22 on the end 23 of a cylindrical core 20, such
as the core 20 shown in FIGS. 2A and 2B, allowing the free end 108
of a finger 102 to seat within the notch 22.
[0064] FIG. 7 illustrates the arcuate-profile of one of the fingers
102. Each finger 102 extends from its fixed end 110 in a first
axial direction and then bends in a radially outward direction
through an arc portion 112 and extends towards the free end 108 in
a second axial direction, which is substantially opposite the first
axial direction. The portion of the finger 102 between the arc
portion 112 and the free end 108 is biased in a radially outward
direction r from an axis of rotation R of the notch finding spring
101.
[0065] As shown in FIGS. 6 and 9, each arc portion 112 has a
reduced width compared to the portions of the finger 102 adjacent
to the arc portion 112. The reduced width defines a circular shaped
space 120 between adjacent fingers 102 that can receive a support
post 230. Retaining the increased width along the remaining
portions of the finger 102 provides strength for the finger 102 and
more surface area with which to frictionally engage the inner
diameter 24 of the core 20.
[0066] In addition, the diameter of the notch finding spring 101
around the arc portion 112 of the fingers 102 is less than the
inner diameter 24 of the core 20, and the diameter of the notch
finding spring 101 around the free ends 108 of the fingers 102 is
greater than the inner diameter 24 of the core 20. Because the
diameter around the arc portion 112 is less than the inner diameter
24 of the core 20, placement of the core 20 over the notch finding
spring 101 is facilitated. And, because the diameter of the notch
finding spring 101 around the free ends 108 of the fingers 102 is
greater than the inner diameter 24 of the core 20, the free ends
108 of the fingers 102 are urged against the inner diameter 24 of
the core 20 or into notches 22 that align with the fingers 102. An
illustration of the notch finding spring 101 positioned within the
notched end 23 of the cylindrical core 20 is shown in FIG. 8.
[0067] The base portion 104 defines an annular collar 114 that
extends in a radially outward direction r from the axis of rotation
R of the notch finding spring 101 to the fixed end 110 of the
fingers 102, as shown in FIGS. 6, 7, and 9. The annular collar 114
includes an inner diameter that approximately matches the outer
diameter of the drive shaft 52, or a mounting shaft extending
axially from the end of the drive shaft 52, allowing the annular
collar 114 to be placed over the end of the drive shaft 52 or
mounting shaft. Alternatively, the base portion 104 can be solid
(not shown) or define an aperture through the center of the base
portion 104, as shown in FIG. 17B, for receiving a fastener, such
as, for example, a screw or bolt, to secure the base portion 104
adjacent to the end 54 of the drive shaft 52.
[0068] One method of manufacturing a notch finding spring 101
includes cutting into a flexible sheet of material, such as
beryllium copper or full-hard 301 stainless steel. The annular
collar 114 is cut into the sheet of material, and the fingers 102
are defined by cutting slots into the material that extend from the
outer diameter of the annular collar 114 to the edge of the sheet
of material. The slots are positioned adjacent to each other and
circumferentially around the outer diameter of the annular collar
114. After the slots are cut, the portion of each finger 102
between the fixed end 110 and the arc portion 112 is bent in a
first axial direction relative to the axis of rotation R of the
notch finding spring 101, the arc portion 112 of each finger 102 is
bent in a radially outward direction, and the portion between the
arc portion 112 and the free end 110 is bent in a second axial
direction that is substantially opposite the first axial direction.
When the notch finding spring 101 is finished, the slots correspond
to the spaces 106 defined between the fingers 102.
[0069] To bend the fingers 102 into the arcuate-shaped profile, a
mandrel, a first hollow cylinder, and a second hollow cylinder can
be utilized. At least a portion of the mandrel has an outer
diameter that is substantially the same as the inner diameter of
the annular collar 114, and the cut form of the notch finding
spring 101 is mounted onto the mandrel by engaging the mandrel into
the annular collar 114. The first hollow cylinder has an inner
diameter that is approximately the same as the desired outer
diameter of the notch finding spring 101 as measured around the
portions of each finger 102 intermediate the fixed end 110 and the
arc portion 112. And, the second hollow cylinder has an inner
diameter approximately the same as the desired outer diameter of
the notch finding spring 101 around the free ends 101. The mandrel
is maneuvered to engage a portion of the cut form into the first
hollow cylinder, bending the fixed ends 110 of the fingers 102 in
the first axial direction. Then, the portions of each finger 102
between the free end 108 and the arc portion 112 are engaged into
the second hollow cylinder, which bends the fingers 102 radially
outward and downward in the second axial direction.
[0070] FIGS. 10 through 12 illustrate exemplary dimensional
specifications for manufacturing the notch finding spring 101 from
a sheet of a beryllium copper alloy having a yield strength of
about 150,000 psi and a thickness Q of 0.005 inches. For example,
as shown in FIG. 10, the inner diameter A of the annular collar 114
is approximately 0.185 inches and the distance B between the center
of the annular collar 114 to the fixed end 110 of each finger 102
is approximately 0.135 inches. To define the twelve fingers 102
shown in FIG. 10, twelve slots corresponding to the twelve spaces
106 are cut into the material. In addition, the inner radius G of
the transition from the fixed end 110 to the portion of the finger
102 intermediate the fixed end 110 and the arc portion 112 is about
0.050 inches, the diameter H of the notch finding spring 101 around
the free ends 108 of the fingers 102 is about 0.558 inches, the
diameter J of the notch finding spring 101 around the arc portions
112 is approximately 0.465 inches, the diameter W of the notch
finding spring 101 around the fixed ends 110 is 0.214 inches, and
the radius K of the portion of the slot that is adjacent the
annular collar 114 is about 0.007 inches. The specifications
further show the portion of the finger 102 extending from the arc
portion 112 to the free end 108 as having a curvature having an
angle L of about 190.degree. and a radius P of about 0.4 inches,
and the arc portion 112 has an angle M of about 25.degree. and a
radius N of about 0.025 inches. In addition, the length Y of the
finger 102 from the arc portion 112 to the free end 108 is about
0.251 inches, and the length X that the free end 108 extends below
a plane of the annular collar 114 is 0.046 inches.
[0071] According to FIG. 11, the angle C from the center of one of
the fingers 102 to the edge of the finger is about 12.degree., the
angle D from the center of one finger 102 to the center of an
adjacent finger 102 is about 42.degree., and the angle E of each
space between the fingers 102 is about 6.degree.. In addition, the
diameter F of the space 106 between two adjacent arc portions 112
is about 0.055 inches.
[0072] FIG. 12 shows another exemplary dimensional specification
for manufacturing the arcuate-shaped fingers 102. For example, the
inner diameter A of the annular collar 114 is about 0.125 inches,
the radius G of the transition from the fixed end 110 to the
portion of the finger 102 intermediate the fixed end 110 and the
arc portion 112 is about 0.010 inches, the outer radius V of the
transition from the fixed end 110 to the portion of the finger 102
intermediate the fixed end 110 and the arc portion 112 is about
0.020 inches, and the arc portion 112 has an angle M of about
25.degree. and a radius N of about 0.025 inches. In addition, the
specifications show the portion of the finger 102 extending from
the arc portion 112 to the free end 108 as having a curvature
having an angle L of about 170.degree. and a radius P of about 0.4
inches. Furthermore, the flexible sheet material out of which the
finger 102 is cut is shown as having a thickness Q of approximately
0.010 inches. The dimensions described above in relation to FIGS.
10 through 12 are exemplary and are one of skill in the art would
understand that variations are within the scope of the
invention.
[0073] The notch finding spring 101 is not limited to the specific
embodiment described above in relation to FIGS. 4A through 12. For
example, in one alternative embodiment, which is shown in FIGS. 14
through 16B, the fingers 102 do not have a reduced width at the
free end 108 or a reduced width at the arc portion 112. Instead,
the width of the fingers 102 gradually tapers from the free end 108
towards the arc portion 112, and the free end 108 has a width that
is approximately matched with the width of a notch 22 in the core
20. In addition, the spaces 106 between the fingers 102 have a
width approximately the same as the diameter of one of the support
posts 230 that extend from the support disk 61. The exemplary cut
detail of a notch finding spring 101 according to this embodiment
is shown in FIGS. 16A and 16B. For example, the angle of each space
106 between the fingers 102 is about 6.degree., and the distance
from the center of the annular collar 114 to the fixed end 110
outeach finger 102 is about 0.1 inches. In another embodiment,
which is not shown, the width of each finger 102 is uniform along
the length of the finger 102.
[0074] In addition, another embodiment of the notch finding spring
101, which is shown in FIGS. 17A and 17B, includes non
arcuate-shaped fingers 102. Instead, the fingers 102 extend
outwardly and downwardly from the base portion 104 without bending
through an arc portion 112.
[0075] As mentioned above, the notch finding mechanism 100 further
includes a support disk 61. According to the embodiment shown in
FIGS. 4A through 6, the support disk 61 includes a plurality of
support posts 230 that extend in an axial direction from the outer
surface 221 of the support disk 61. The support posts 230 are
positioned circumferentially around the central aperture of the
support disk 61. When the annular collar 114 of the notch finding
spring 101 is positioned over the drive shaft 52 and adjacent the
support disk 61, each of the spaces 106 between the fingers 102
aligns with and receives one of the support posts 230. By extending
through the each of the spaces 106 between the fingers 102, the
support posts 230 prevent the fingers 102 from excessive torsional
deflection. In another embodiment in which a clutch assembly 60 is
not used, the support posts 230 extend axially from the drive disk
55.
[0076] In the embodiment shown in FIG. 13, the support disk 61
includes an annular groove 220 on the outer surface 221 of the
support disk 61, which is the surface opposite the mounting surface
64. The annular groove 220 is adapted for seating the free ends 108
of the fingers 102 of the notch finding spring 101. By seating the
free ends 108 in the annular groove 220, the free ends 108 are
prevented from being forced in a radially inward direction past the
inner diameter of the annular groove 220, thereby protecting the
fingers 102 from excessive radial deflection.
[0077] Assembly of Notch Finding Mechanism to Drive Assembly The
rotational energy of the drive motor 51 is transferred to the core
20 by securing the notch finding spring 101 to the support disk 61
and placing the core 20 over the notch finding spring 101. To
secure the notch finding spring 101 adjacent to the support disk 61
and to hold the support disk 61 in frictional contact with the
drive disk 55, one embodiment of the notch finding mechanism 100
further includes a compression spring 250, a washer 255, and a
threaded bolt 256. As shown in FIGS. 5 and 13, the support disk 61
and the intermediate frictional disks 201, 202, 203 are placed over
the end 54 of the drive shaft 52 and stacked adjacent the drive
disk 55, as described above in relation to FIG. 5. Then, the
annular collar 114 of the notch finding spring 101 is placed over
the end 54 of the drive shaft 52 and seated adjacent the support
disk 61.
[0078] Next, a helical compression spring 250 is placed over the
end 54 of the drive shaft 55 and seated adjacent the annular collar
114 of the notch finding spring 101. A washer 255 is then placed
intermediate the helical compression spring 250 and a head portion
of a threaded bolt 256, and a threaded portion of the threaded bolt
256 is engaged through the center of the compression spring 250 and
into a threaded aperture 260 that extends axially from the end 54
of the drive shaft 52 or mounting shaft towards the driven end 53
of the drive shaft 52. When the bolt 256 is fully engaged in the
threaded aperture 260, the bolt 256 urges the washer 255 towards
the helical compression spring 250, which forces the compression
spring 250 to push the annular collar 114 of the notch finding
spring 101 into frictional engagement with the support disk 61 and
the support disk 61 into frictional engagement with the drive disk
55 via the intermediate disks 201, 202, 203. FIG. 13 illustrates a
cross-sectional view of the notch finding spring 101 described
above in relation to FIG. 4A engaged into the notched end of the
core 20 and coupled to the drive assembly 50 via the clutch
assembly 60 described above in relation to FIG. 5.
[0079] When the core 20 is placed over the notch finding spring
101, a finger 102 may or may not be aligned with a notch 22. If a
finger 102 is aligned with a notch 22, the bias of the finger 102
causes it to seat into the notch 22 automatically. If a finger 102
is not aligned with a notch 22, the drive assembly 50 rotates the
notch finding spring 101 until a finger 102 aligns with the notch
22. Because a finger 102 automatically seats within a notch 22 when
the finger 102 is aligned with the notch 22, the operator does not
have to adjust the core 20 once the core 20 is placed over the
notch finding spring 101.
[0080] In another embodiment, which is not shown, the notch finding
spring 101 is coupled to the drive shaft 52 without a clutch
assembly 60. Support posts 230 extend axially from the drive disk
55 and are positioned circumferentially around the axis of rotation
of the drive shaft 52. The annular collar 114 of the notch finding
spring 101 is placed over the end 53 of the drive shaft 52 and
positioned to seat adjacent to the surface of the drive disk 55
such that the spaces 106 between the fingers 102 are aligned with
and receive the support posts 230. The use of a compression spring
250, washer 255, and threaded bolt 256, such as described above in
relation to FIG. 13, can be utilized to secure the notch finding
spring 101 into frictional contact with the drive disk 55.
[0081] Another embodiment of the invention is a radially biased
spring for axially coupling a drive shaft to a hollow cylindrical
shaft. The radially biased spring includes a base portion and a
plurality of fingers. Each of the fingers includes a fixed end and
a free end, and the fixed end of each finger is integrally attached
to the base portion. The fingers are positioned circumferentially
around the base portion so as to define a plurality of spaces
between the fingers. The base portion of the radially biased spring
is securely mounted to the end of the drive shaft so that the fixed
ends of the fingers are adjacent the end of the drive shaft and the
free ends are positioned adjacent the body of the drive shaft. When
a hollow cylindrical shaft is placed over the fingers, the fingers
are biased in a radial outward direction against the inside
diameter of the cylindrical shaft to couple the drive shaft to the
cylindrical shaft.
[0082] In an alternative embodiment, shown in FIG. 18, a radially
biased spring includes a base portion 104 and a plurality of
fingers 302 that extend in an axial direction from the base portion
104 away from the end of the drive shaft 52 towards a cylindrical
shaft 320. The fingers 302 are biased in a radially outward
direction, and each finger 302 includes a protrusion 303 that
extends in a radially outward direction from the finger 302. The
cylindrical shaft 320 includes a driven end 321, and notches 322
are positioned along an inner diameter of the cylindrical shaft 320
adjacent to the driven end 321. The notches 322 are positioned such
that they will align with the protrusions 303 on the fingers 302
when the fingers 302 are engaged into the cylindrical shaft 320.
The radially outward bias of the fingers 302 urges the protrusions
303 on the fingers 302 into engagement with the notches 322 in the
cylindrical shaft 320, coupling the cylindrical shaft 320 to the
drive shaft 52.
[0083] The protrusions 303 in the embodiment shown in FIG. 18 are
rectangular shaped. However, the protrusions 303 can take on
alternative shapes, such as spherical, triangular, or trapezoidal,
depending on the shape of the notches 322 in the cylindrical shaft
320. For example, in FIG. 19, the protrusions 303 are circular
shaped and the notches 322 are dimple shaped. This embodiment
advantageously provides a self-clutching assembly by allowing the
protrusions 303 to disengage the dimple shaped notches 322 when the
torque at the end of the drive shaft 52 exceeds a predetermined
amount.
[0084] In another embodiment, shown in FIG. 20, the protrusions 303
on the fingers 302 extend in a radially inward direction and the
fingers 302 are biased in a radially inward direction. In addition,
the cylindrical shaft 320 includes notches 322 positioned along its
outer diameter adjacent to the driven end 321 of the cylindrical
shaft 320. To couple the drive shaft 52 to the driven end 321 of
the cylindrical shaft 320, the fingers 302 are engaged into the
driven end 321 of the cylindrical shaft 320, and the bias of the
fingers 302 urges the protrusions 303 on the fingers 302 into
engagement with the notches 322 on the outer diameter of the
cylindrical shaft 320.
[0085] In yet another embodiment, shown in FIG. 21, the fingers 302
are biased in a radially inward direction, and each finger 302
includes two arcs that define an S-shape. A first arc 304 is
positioned adjacent to the free end of the finger 302 and is convex
relative to the axis of rotation of the drive shaft 52, and a
second arc 305 is positioned adjacent to the first arc 304 and is
concave relative to the axis of rotation of the drive shaft 52. The
cylindrical shaft 320 includes a toroidal shaped collar 325
extending in a radially outward direction from the outer diameter
of the cylindrical shaft 320 adjacent to the driven end 321 of the
cylindrical shaft 320. The collar 325 has a diameter that is
greater than the outer diameter of the cylindrical shaft 320 and
slightly less than the inner diameter defined by the second arcs
305 of the fingers 302. The cylindrical shaft 320 further includes
a plurality of notches 322 positioned along the outer diameter of
the cylindrical shaft 320 between the toroidal collar 325 and the
non-driven end of the cylindrical shaft 320. To couple the drive
shaft 52 to the driven end 321 of the cylindrical shaft 320, the
fingers 302 are engaged over the driven end 321 of the cylindrical
shaft 320 and the bias of the fingers 302 urges the second arcs 305
of the fingers 302 into engagement with the toroidal collar 325 and
the first arcs 304 into engagement with the notches 322 on the
outer diameter of the cylindrical shaft 320. The engagement of the
second arcs 305 with the toroidal collar 325 prevents axial
movement of the cylindrical shaft 320 relative to the drive shaft
52, and the rotational energy from the drive shaft 52 is
transferred to the cylindrical shaft 320 through the engagement of
the first arcs 304 into the notches 322 adjacent to the toroidal
collar 325.
[0086] FIG. 22 shows a variation of the embodiment described in
relation in FIG. 21 wherein the cylindrical shaft 320 has a
toroidal collar 325 that extends from the outer diameter of the
cylindrical shaft 320 in a radially outward direction, and the
notches 322 are positioned along a crest 326 of the toroidal collar
325 on the inner diameter of the cylindrical shaft 320. The fingers
302 include at least one arc 306 that is concave relative to the
axis of rotation of the drive shaft 52, and upon engaging the
fingers 302 into the cylindrical shaft 320, the arcs 306 on the
fingers 302 engage into the toroidal collar 325 and the notches 322
therein. The engagement of the arcs 306 with the toroidal collar
325 prevents axial movement of the cylindrical shaft 320 relative
to the drive shaft 52, and the rotational energy from the drive
shaft 52 is transferred to the cylindrical shaft 320 through the
engagement of the arcs 306 into the notches 322 on the toroidal
collar 325.
[0087] In yet another alternative embodiment, fingers 302 extend
axially from the circumference of a cylinder 310 having a threaded
exterior portion 311, as shown in FIG. 23. The threaded exterior
portion 311 engages a threaded inner diameter 340 of a drive shaft
52. The fingers 302 include protrusions 303 that extend in a
radially inward direction, and these protrusions 303 engage notches
322 positioned within a trough of an annular collar 330 that
extends in a radially inward direction from the outer diameter of
the cylindrical shaft 320 when the fingers 302 are engaged over the
cylindrical shaft 320. If the torque on the drive shaft 52 exceeds
a particular amount at the end of the drive shaft 52, the
protrusions 303 on the fingers 302 disengage from the notches 322
or the threaded portion 311 of the cylinder 310 disengages from the
threaded inner diameter 340 of the drive shaft 52.
[0088] FIG. 24 illustrates another embodiment in which the end of
the drive shaft 52 includes a first face 345 that includes a
plurality of protrusions 341 extending from the first face 345 in
an axial direction away from the drive shaft 52. The cylindrical
shaft 320 includes a driven end 321 that has a second face 350, and
the second face 350 of the driven end 321 includes a plurality of
notches 352 that align with the protrusions 341 on the drive shaft
52 and are configured for receiving the protrusions 341 when the
driven end 321 of the cylindrical shaft 320 and the end of the
drive shaft 52 are place adjacent to each other. When the
protrusions 341 of the drive shaft 52 are engaged into the notches
352 on the cylindrical shaft 320, the rotational energy of the
drive shaft 52 can be transferred to the cylindrical shaft 320. In
addition, a plurality of fingers 302 extend from the end of the
drive shaft 52 in an axial direction towards a cylindrical shaft
320. To prevent the axial movement of the cylindrical shaft 320
relative to the drive shaft 52, the fingers 302 further include a
protrusion 303 that extends in a radially inward direction, and the
protrusion 303 engages a groove 330 in the outer diameter of the
cylindrical shaft 320.
[0089] FIGS. 25 through 28 illustrate exemplary alternative
embodiments of finger shapes. For example, FIGS. 25 and 26
illustrate fingers 302 that have a free end 108, a fixed end 110,
and an elongated body extending between the free end 108 and the
fixed end 110. A protrusion 303 extends from the elongated body
between the fixed end 110 of the finger 302 and a middle portion of
the elongated body. The protrusion 303 may extend in a radially
inward direction as shown in FIG. 25 or in a radially outward
direction as shown in FIG. 26.
[0090] FIG. 27 illustrates another embodiment of a finger 302 that
has a free end 108, a fixed end 110, and an elongated body
extending between the free end 108 and the fixed end 110. A
protrusion 303 extends from a middle portion of the elongated body,
and the free end 108 of the finger 302 defines a hook shape. The
hook-shaped free end 108 can bend radially inward or radially
outward to facilitate the insertion of the finger 302 into the
inner diameter of the cylindrical shaft or onto the outer diameter
of the cylindrical shaft, respectively.
[0091] FIG. 28 illustrates a finger 302 having a fixed end 110, a
free end 108, and a U-shaped body that extends between the free end
108 and the fixed end 110 and includes an arcuate portion 401. The
finger 302 extends from a base portion 104 in a first axial
direction, bends in a radially outward direction through the arc
portion 401, and extends in a second axial direction to the free
end 108, wherein the first axial direction is substantially
opposite the second axial direction. In addition, the finger 302
includes a protrusion 303 that extends in a radially outward
direction and is positioned between the arc portion 401 and the
free end 108 of the finger 302. The finger 302 is suited for
engaging notches located along the inner diameter of a cylindrical
shaft. In an alternative embodiment, which is not shown, the finger
extends from the base portion in the first axial direction, but
bends in a radially inward direction through the arc portion before
extending in the second axial direction to the free end. The finger
also includes a protrusion positioned between the arc portion and
the free end of the finger, but unlike the finger shown in FIG. 28,
the protrusion extends in a radially inward direction. This finger
is adapted for engaging notches located along the outer diameter of
the cylindrical shaft.
[0092] In other alternative embodiments, the fingers 302 described
above are positioned on the driven end 321 of the cylindrical shaft
320, and the structure for engaging the fingers 302 is positioned
on the drive end of the drive shaft 52. For example, as shown in
FIG. 29, fingers 302 extend from the driven end 321 of the
cylindrical shaft 320 towards the drive shaft 52. The drive shaft
52 includes a hollow cylindrical portion at the drive end that
includes a plurality of notches 441. The fingers 302, which are
biased in a radially outward direction, engage the notches 441 and
transfer rotational energy from the drive shaft 52 to the
cylindrical shaft 320.
[0093] Many modifications and other embodiments of the inventions
set forth herein will come to mind to one skilled in the art to
which these inventions pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the inventions are
not to be limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended concepts. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *