U.S. patent application number 09/450119 was filed with the patent office on 2002-05-23 for shape memory alloy actuators for toy vehicles.
Invention is credited to Shiu, Boon-Wai, Young, Andrew Meng-Cheung, Zhou, Li-Min.
Application Number | 20020061695 09/450119 |
Document ID | / |
Family ID | 23786839 |
Filed Date | 2002-05-23 |
United States Patent
Application |
20020061695 |
Kind Code |
A1 |
Zhou, Li-Min ; et
al. |
May 23, 2002 |
SHAPE MEMORY ALLOY ACTUATORS FOR TOY VEHICLES
Abstract
This invention provides a toy vehicle incorporating actuators
made from a shape memory alloy material. These actuators may be in
the form of a spring, wire or similar form that has a mechanical
response upon the application or removal of heat. In particular,
wires may be connected about hinges for doors, hoods, convertible
roofs and other such items which, upon the application of heat to
the wire of shape memory ally, causes contraction of the wire and
rotation about the hinged joint of the body part. As such shape
memory ally actuators are generally only operable in a single
direction, they may be provided in pairs or in opposition to
another biasing means to cause the opposed rotation about the joint
when desired. The preferred source of heat to the shape memory
alloy actuators is through the provision of electrical energy to
the wire to create heat through the resistance of the shape memory
alloy actuator itself.
Inventors: |
Zhou, Li-Min; (Kowloon,
HK) ; Shiu, Boon-Wai; (Kowloon, HK) ; Young,
Andrew Meng-Cheung; (Kowloon, HK) |
Correspondence
Address: |
JACOBSON PRICE HOLMAN & STERN
THE JENIFER BUILDING
400 SEVENTH STREET NW
WASHINGTON
DC
20004
|
Family ID: |
23786839 |
Appl. No.: |
09/450119 |
Filed: |
November 26, 1999 |
Current U.S.
Class: |
446/14 |
Current CPC
Class: |
A63H 17/26 20130101 |
Class at
Publication: |
446/14 |
International
Class: |
A63H 033/00 |
Claims
1. A toy vehicle comprising: a main body portion; at least one
component attached to or with said main body portion capable of
reciprocating motion between a first position and a second
position; a drive mechanism to activate motion of said movable
component including at least one element formed from a shape memory
alloy that may drive said motion upon the supply of heat to said
shape memory alloy component; and means to heat said shape memory
alloy component.
2. A toy vehicle as claimed in claim 1 wherein said at least one
element formed from a shape memory alloy is in the form of a thin
elongate element.
3. A toy vehicle as claimed in claim 2 wherein said thin elongate
element comprises a wire or spring.
4. A toy vehicle as claimed in claim 2 wherein said means to heat
said shape memory alloy component comprise a source of electrical
current and means to communicate current through said thin elongate
element.
5. A toy vehicle as claimed in claim 1 wherein said at least one
component attached to or with said main body portion comprises a
rotational mounted door or hood of said vehicle.
6. A toy vehicle as claimed in claim 1 wherein said at least one
component attached to or with said main body portion comprises a
steering arm to steer said vehicle.
7. A toy vehicle as claimed in claim 1 wherein said at least one
component attached to or with said main body portion comprises a
suspension element to raise or lower said main body portion with
respect to a wheel.
8. A toy vehicle as claimed in claim 1 wherein said at least one
component attached to or with said main body portion comprises a
drive shaft for motion of said vehicle.
Description
FIELD OF THE INVENTION
[0001] This invention relates to toy vehicles and, in particular,
the use of shape memory alloys to activate moving parts of such toy
vehicles.
BACKGROUND OF THE INVENTION
[0002] There is a popular market for toy vehicles throughout the
world. In many instances, the consumer is looking for as much
activity and play value in the vehicle as possible together with as
much control over the parts of the vehicle.
[0003] Although many such vehicles may be motorized, this generally
comprises an electric motor powered by batteries to run a drive
train and often an electrical wiring loom for lights or similar.
However, more subtle movements of components such as the opening of
doors, hoods, steering mechanisms and similar items have generally
proved too costly or difficult to incorporate individual drive
mechanisms for these components. As a result, such items as doors
on a miniature replica or similar are likely to be made with simple
hinge mechanisms to allow them to be manually opened and
closed.
[0004] Not only is cost affected in providing drive mechanisms for
such components, but the size constraints often preclude the
fitment of items to allow such movements. If they can be fitted at
all, the toy designer is severely constrained in further aspects of
the design to allow incorporation of the additional components.
OBJECT OF THE INVENTION
[0005] It is an object of the present invention to provide shape
memory alloy actuators for toy vehicles to overcome some of these
problems with prior art toy vehicles or at least provide the public
with a useful choice.
SUMMARY OF THE INVENTION
[0006] Accordingly, in the first aspect, the invention may broadly
be said to consist in a toy vehicle comprising:
[0007] a main body portion;
[0008] at least one component attached to or with said main body
portion capable of reciprocating motion between a first position
and a second position;
[0009] a drive mechanism to activate motion of said movable
component including at least one element formed from a shape memory
alloy that may drive said motion upon the supply of heat to said
shape memory alloy component; and
[0010] means to heat said shape memory alloy component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further aspects of the invention will now be described with
reference to preferred embodiments and drawings in which:
[0012] FIG. 1 is a perspective view of a toy vehicle including at
least one embodiment of the invention;
[0013] FIG. 2 is a cross sectional elevational of a steering
mechanism in accordance with one possible embodiment of the
invention;
[0014] FIGS. 3A to E show various views of an activation system for
a hood, door or similar item in accordance with a further
embodiment of the invention;
[0015] FIG. 4 shows a cross sectional elevation through a
suspension mechanism in accordance with a yet further embodiment of
the invention;
[0016] FIG. 5 shows cross sectional elevation of a top for a toy
convertible vehicle in accordance with a yet further embodiment of
the invention;
[0017] FIGS. 6A to C show cross sectional elevations through the
activation mechanism for a top of a convertible toy vehicle in
accordance with a yet further embodiment of the invention; and
[0018] FIGS. 7A and 7B show plane and elevational views of a
vehicle drive mechanism in accordance with a yet further embodiment
of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] This invention relates to the use of shape memory alloy
actuators, particularly in a vehicle 1 as shown in FIG. 1. This
particular figure shows a diagrammatic vehicle in the form of a car
although will be appreciated that the preferred embodiments may be
applied to a wide variety of vehicles including but not limited to,
cars, motorcycles, bicycles, tricycles, tanks, trains, emergency
vehicles, etc. In particular, aspects of the invention may be
applied to those vehicles where moving parts are particularly
desirable such as toy construction, agricultural and earth-moving
vehicles.
[0020] In all such vehicles, the provision of small drive units in
the form of electrical motors and gear boxes for the moving parts
is a significant portion of the cost of the vehicle. Additionally,
the size of these items can either preclude their inclusion or
cause considerable constraints on the design of the vehicle so that
they may be incorporated.
[0021] This invention seeks to provide alternative activation of a
number of these items by the use of shape memory alloys. Shape
memory alloys themselves come in a variety of forms although
perhaps the most common is a nickel titanium alloy. Such alloys can
be manufactured in the form of wires or thin stripes for use
directly of for manufacture into springs or similar.
[0022] A shape memory alloy as referred to in the description is an
item capable of phase transformation in response to thermal
changes. The materials undergo a phase transformation in their
crystal structure when cooled from the stronger, high temperature
form to the weaker, lower temperature form.
[0023] These materials are generally easily deformed to a new shape
when at the weaker low temperature form. However, upon the
application of energy to heat the material, a phase transformation
occurs which causes the material to recover its previous shape with
considerable force.
[0024] The composition of the alloy allows considerable variation
in the temperatures at which this transformation takes place. The
transformation itself may occur over a range of just a few degrees
Celsius and the composition of the alloy allows the start and
finish temperatures of the transformation to be controlled within a
matter of a few degrees if necessary.
[0025] Taking the example of the shape memory alloy formed into a
wire, the low temperature form is a weak, easily deformable wire.
However, once heated, the wire contracts to its high temperature
form and is capable of applying a considerable tensile force in the
process. It should be noted that no similar force is generated in
the form of compression when moving to the low temperature form
and, therefore, the alloys are generally more suitable for a single
actuation in a single direction.
[0026] To provide more useful actuators for moving parts, such
wires may be incorporated in tandem or a single wire may be used in
conjunction with a spring or similar means to assist with the
motion in the opposed direction.
[0027] Although useful in a number of circumstances, such actuators
are preferably applied where reciprocating motion over a limited
amount of travel is required. Of course, with the use of mechanical
linkages, such motion may be transformed into rotational motion of
a shaft or similar.
[0028] The use of shape memory actuators may remove the need for
individual motors. Furthermore, the relatively thin wires can be
incorporated in confined spaces in the vehicle to allow
considerable flexibility in the design of vehicles.
[0029] The source of heat to activate the shape memory alloy may
come in any convenient form. A heat sink may be used to retain
thermal energy for use when desired and the actuators merely
brought into thermal communication with that heat sink as required.
Perhaps one of the easier forms of applying heat to or creating
heat in such actuators may be in the form of an electrical current.
The actuators may be placed in a variety of locations throughout a
vehicle and controlled through the controlled connection to a
source of electrical current such as batteries or similar. Once a
current has passed through the wires, the wire may heat up through
the transformation temperature and cause the phase
transformation.
[0030] Various specific embodiments are further described with
reference to the figures. Referring to FIG. 1 the actuators may be
applied to the steering mechanism 2, a suspension system 3, doors
4, a vehicle hood 5 or various other parts as described.
[0031] Turning initially to FIG. 2, a cross sectional plan view is
shown through a steering mechanism 2. In this view, a wheel 6 is
attached to an axle 7 and a steering arm 8. The steering arm may be
pivotally mounted on a mounting 9 such that the wheel 6 is
rotatable about the pivotal mounting 9.
[0032] An actuating wire 10 may be attached to the steering arm 8
at a distance 11 from the pivotal mounting 9. As shown in this
embodiment, the attachment of the wire 10 to the steering arm 8 may
simply comprise the passage of the wire 10 through an aperture 12
in the steering arm 8 and a suitable stop 14 applied to the end of
the wire 10 to stop the wire 10 being removed from the aperture
12.
[0033] A distal end 15 of the wire 10 may be attached to a fixed
point on the vehicle 1.
[0034] Upon the application of heat to the wire 10, the wire will
constrict to its high temperature form. The pull on the wire 10
between the fixed point 15 and the end 14 will create a turning
moment in the steering arm 8 about the pivotal mounting 9. As a
result, the wheel 6 will turn in the direction indicated by arrow
16.
[0035] As may be appreciated, this is a relatively simplistic
mechanism. At present, this embodiment only turns a single wheel in
a single direction. However, the incorporation of a tie rod 17
between the steering arms 8 of a front or rear pair of wheels will
ensure corresponding movement of the associated wheel.
[0036] If it is desired to turn the wheel 6 to the opposed
direction, a mirror image of this actuators may be applied to the
wheel in the front or rear pair connected by the tie rod 17. On
that wheel, activation of a similar shape memory wire will cause
the opposed wheel to turn in the opposite direction and drive this
wheel 6 through the tie rod 17.
[0037] In this manner, a relatively simple mechanism has been
provided to turn the wheels left or right simply upon the
application of heat to each of a pair of shape memory wires.
[0038] To complete the embodiments, it may be desirable to include
a stabilizing mechanism 18 in the form of a compression spring or
similar to return the wheels to the position for direct forward
travel. Upon removal of the heat source from either actuator 10,
the springs or similar stabilizing mechanisms 18 will dominate and
allow the low temperature form of the wires to be easily
manipulated into the central position for direct forward
travel.
[0039] Again, it is intended that the stabilizing mechanism such as
the spring 18 can easily be placed between the steering arm 8 and a
fixed point 19 on the body of the vehicle.
[0040] A yet further range of actuators is shown in FIGS. 3A to 3E,
each applied, in this instance, to a body panel of the vehicle such
as a door or hood to the intended engine compartment.
[0041] Referring to FIG. 3A, a hood of a vehicle 5 can be seen to
be mounted on a support arm 20 which itself is pivotally mounted on
a rotational support 21. The hood 5 can rotate about the rotational
mounting 21 to assume opened and closed positions.
[0042] A first actuation system is shown in FIG. 3A in which a pair
of shape memory alloy actuators 22 and 23 are utilized. As can be
seen from the diagram, each of these actuators applies a rotational
force on the support arm 20 about the rotational mounting 21 and
each works in an opposed direction to the other. Upon supplying
heat to either of the wires 22 or 23, the reduction in length of
the wire will create a pull on the ends 24 and 25 respectively
supported in the support arm 20. Alternate activation of the wires
can open or close the hood as desired.
[0043] This particular system shows the use of two shape memory
alloy actuators, one for each of the opened and closed motions of
the hood 5. It will be appreciated that is possible to only use a
single actuator operating against an opposed biasing means (not
shown) such as a spring or similar. The application of heat to an
actuator to, for example, open the hood 5 may do so against the
action of a compression spring which will then return the hood th
the closed position upon removal of the heat source.
[0044] As shown an actuation requires the continuous supply of heat
to the shape memory alloy actuator to retain the body panel in the
opened position, it may be preferred to provide a balanced body
panel such as the hood 5 that is capable of rotating to a stable
position in both the opened and closed positions and using
duplicate actuators as shown in FIG. 3A to reduce continuous energy
requirements if it is desired to leave the hood 5 open for
sometime.
[0045] An alternative actuation is shown in FIG. 3B. Again, the
general arrangement of the items is similar to the previous
embodiment although, in this case, the actuators extend rearwardly
of the opening panel rather than enclosing the hinge and actuating
from the alternative direction.
[0046] It should be noted that in both embodiments, it is intended
that the end of the shape memory alloy actuator distal from the
hinge is connected to a fixed point on the body of the vehicle such
that the reduction in length of the wire will cause the ends 24 and
25 connected to the support member 20 to move and create the
rotation.
[0047] Referring to FIGS. 3C, 3D and 3E, a further embodiment is
shown again with reference to a hood 5 of a vehicle.
[0048] Again the general arrangement is very similar with the hood
5 supported on a support arm 20 mounted about a rotational mounting
21. In this case, a T-shaped end piece to the support arm is
provided around the rotational mounting 21 with the actuating wires
22 and 23 connected to the T-shaped end piece. This provides the
wires with some increased spacing of the line of actuation away
from the rotational mounting 21 so as to create a greater turning
moment if desired.
[0049] FIG. 3E shows a detailed view of the wire 23 and its end
piece 25 which may be provided as an enlarged end or similar to
retain the wired 23 in communication with the T-shaped end piece 27
having passed through an aperture 28. Numerous other forms of
connection could be used.
[0050] Referring to FIG. 3D, a plan view of the arrangement is
shown.
[0051] Yet a further embodiment of the invention is shown in FIG.
4. In this instance, the embodiment comprises a suspension system 3
for a vehicle.
[0052] As shown, a wheel 6 is rotationally mounted on an axle 7
which itself is connected to a suspension strut 31. It is intended
that the connection between the axle 7 and the strut 31 allows
movement of the axle 7 along the strut 31 relative to the support
frame 30 of the vehicle.
[0053] Shape memory alloy members 32 and 33 are provided, in the
preferred embodiment, in the form of springs. These are on opposed
sides of the axle 7 and its connection to the support strut 31.
[0054] Like the wires explained in the previous embodiments, a
spring from shape memory alloy will also contract upon the
application of heat or otherwise transform into its high
temperature form. This allows movement of the springs 32 and 33
upon the application of heat to either spring. As with the previous
embodiments, the application of heat may also be in the form of
applying a current through the wire to create an increase in
temperature through the resistance of the wire or spring.
[0055] By providing the actuating elements on either side of the
axle 7, the position of the axle 7 on the support strut 31 and be
manipulated by the application of heat to one or other of the shape
memory alloy elements. This allows the vehicle to be raised or
lower as desired or through the sequencing of heat to each spring,
the vehicle may be made to jump or dance.
[0056] As with the previous embodiments, a single shape memory
alloy actuator may be paired with a normal compression or tension
spring or other biasing means to oppose the actuation of the shape
memory alloy element.
[0057] Although this embodiment has been described with reference
to the shape memory alloy elements in the form of springs,
alternative elements such as a direct wire from the axle 7 over the
top of the support strut 31 to a fixed point on the vehicle can
cause a similar motion of the axle 7 along the support strut 31.
The advantage of springs is that they may continue to provide some
suspension and oscillating motion after a single actuation.
[0058] Yet a further embodiment of this invention is shown in FIG.
5.
[0059] In this embodiment, shape memory alloy actuators are used to
actuate the supports for a roof structure of a convertible toy
vehicle. As with many other items on the toy vehicle, automation or
control over the sequenced movements to extend or retract a roof
for a convertible vehicle has proved difficult.
[0060] In the embodiment shown in FIG. 5, the convertible top is
formed over the main frame of the cabin of the vehicle 40. The top
may be a flexible material spread over support struts 41 and 42
forming the majority of the actuated members for the top. These
themselves may by supported by a further arm or member 43. This
further arm or member 43 may be contained within the recess 44 in
which the retracted convertible top may be housed and assist in
extending the convertible top although does not need to be covered
top is housed may be enclosed by one or, in this case, two covering
portion 45 and 46.
[0061] Referring to FIG. 5, each of the movable members 41 to 46 as
shown in this embodiment requires controlled rotation about a
pivotal mounting to the main body or another of the support
members. Referring to the convertible top supports 41 and 42, it
can be seen that the interconnection between these being the
rotational joint 47 may be controlled by shape memory alloy
actuators 48 and 49 in the form of wires. Again, as with previous
embodiments, the application of heat to these wires will cause
either wire to contract as desired and the connection of the wires
from a fixed point on member 42 to a fixed point on member 41
ensures that rotation about joint 47 occurs upon contraction of the
shape memory alloy element. Independent control over the actuators
48 and 49 allows the movement about the joint 47 to be controlled
in either direction as required.
[0062] Referring to the pivotally mounted element 46 to enclose the
recess 44, it can be seen that the shape memory alloy actuators 51
and 52 act about the rotational joint 50. As shown
diagrammatically, each of these actuators may be connected to wires
53 and 54 as shown to supply current to the actuators 51 and 52. In
this preferred form, electrical current is used to generate heat in
the actuators to control the shape transformation.
[0063] The supply of current through wires 53 and 53 may be
controlled by a suitable switching mechanism 55 that itself may
include a microprocessor. The advantage or such an arrangement is
that individual means for communicating electrical current may be
attached to each and every shape memory alloy actuator in the
figure as shown. In this manner, the microprocessor can control the
supply of heat to each wire to provide sequenced movements of each
of the joints necessary to control the convertible top.
Alternatively, a wire of each pair of actuators may be electrically
connected in a series or parallel with another or the actuators if
two of the joints will always be rotated simultaneously. The
designer of the toy vehicle has the choice of either sequenced or
simultaneous actuation of each joint.
[0064] As with the previous embodiments, again the actuation is by
two shape memory alloy actuators for each rotational joint. This
may again be provided as a single shape memory alloy actuator and a
biasing means in opposition to the actuator. The biasing means on
rotational joints could include a coil spring about the joint which
overcome by the force of the actuator in one direction. Once the
actuator returns to its low temperature form, the biasing means may
dominate and cause the opposed rotation.
[0065] A further embodiment of a convertible top is shown in FIGS.
6A to 6C. In this instance, the convertible top 60 may be actuated
by a single movement controlled by shape memory alloy actuators 61
and 62 acting about a rotational mounting 65 of the arrangement to
the main body of the vehicle.
[0066] In this arrangement, each of the extending members to
support the convertible top 60 are provided as a part of members to
form a parallelogram structure 63 as shown. FIGS 6B and 6C show the
sequenced collapsing of the parallelogram of member 63 and
convertible top 60. Rotation of only one member 66 about its
connection to the main body of the vehicle may force simultaneous
rotation of its paired member 67 and through the linkage
arrangement 68, cause rotation of the more distal pair of members
69 and 70. This pair of members may be rotationally mounted at
different points on the convertible top 60 so as to also cause
rotation of that member 60 with respect to the pair of supporting
members 69 and 70. Such an arrangement reduces the number of
actuators required to extend the convertible top by replacing some
of the actuators with mechanical linkages.
[0067] Referring to FIGS. 7A and 7B, a yet further embodiment of
the invention is shown. In this instance, shape memory alloy
actuators 80 and 81 are used to create drive of a shaft 82. By
coiling the actuators 80 and 81 about the shaft 82, a contraction
in length of the actuators 80 or 81 will force rotation of the
shaft 82 as the wire uncoils from the shaft 82. In this manner, the
actuators are able to create rotation of an element such as shaft
82 of greater than 360 degrees. Such a method of actuation in the
embodiment shown in 7A is used to drive a gear 83 which itself acts
on a further gear 84 acting about shaft 86. A further gear 85
connected to shaft 86 may act on a yet further gear 87 acting about
shaft 88. This sequence of gears and rotational shafts allows the
original rotation of shaft 82 to be geared up to drive shaft 88
which is provided as the drive shaft for wheel 6 as shown.
[0068] In this manner, the shape memory alloy actuator 80 is alone
capable of driving the wheel 6 to cause motion of the vehicle as a
whole and replace the main drive mechanism of the vehicle.
[0069] The arrangement is shown in said elevation in FIG. 7B to
further demonstrate the sequencing of the various gears.
[0070] As shown in this embodiment, again two actuators 80 and 81
are used in opposition to each other. These will allow forward and
reverse drive to be applied although the total distance of travel
is restricted to the degree of contraction of these actuators and
the gearing involved. Therefore, only limited forward travel is
available before the rotation of the wheel 6 must be reversed.
[0071] Although this embodiment shows a drive mechanism in which
the actuators 80 and 81 provide oscillating forward and reverse
rotation of shaft 82 and, thereby, oscillating forward and reverse
rotation of the wheel 6, other arrangements are possible. Many
other mechanical mechanisms are well known to transfer rotational
oscillating motion of a shaft into continuous rotation in a single
direction only. The incorporation of such a mechanism could allow
alternating activation of the shape memory alloy actuators to cause
continuous rotation of the wheel 6 in a single direction if
desired. However, such mechanisms may be more expensive.
[0072] Thus it can be seen that this invention provides a variety
of actuators for use throughout the vehicles. The use of shape
memory alloy in the form of a wire, spring or similar allows very
small elements to be connected to the item for which motion is
desired. These wires can be incorporated within the spaces between
body panels of the vehicles and can be controlled by any convenient
heat source. The use of electrical current is a preferred example
as an electrical wire to the shape memory alloy element is again an
easier method of transportation of energy to create heat. This also
allows programmable control over the actuators as desired when used
in conjunction with microprocessor or similar to switch current to
and from various actuators throughout the vehicle.
[0073] Although this invention has been described with reference to
a number of preferred embodiments, it will be appreciated that the
invention is not restricted to those particular examples but
instead defined by the scope of the appended claims. Reference to
particular integers is deemed to incorporate known equivalents
where appropriate and items referred to in the singular may also
include the plural if desired.
* * * * *