GB2279574A

GB2279574A - Wheelchair attachment

Info

Publication number: GB2279574A
Application number: GB9314040A
Authority: GB
Inventors: Stephen Bowers
Original assignee: R J MOBILITY Ltd
Current assignee: R J MOBILITY Ltd
Priority date: 1993-07-07
Filing date: 1993-07-07
Publication date: 1995-01-11
Anticipated expiration: 2013-07-07
Also published as: GB2279574B; GB9314040D0

Abstract

A wheelchair 2 has an attachment 4 which enables a ball or puck 6 to be fired under the control of the user of the wheelchair. The attachment 4 has a control unit 8 for controlling the operation of the attachment 4. This control enables a selection of the power of the shot to be made and also a selection of when the ball or puck 6 is to be fired. The attachment 4 has means for retaining the puck 6 so that the operator of the wheelchair can reverse without leaving the puck 6 behind. <IMAGE>

Description

WHEELCHAIR ATTACHMENT This invention relates to a unit for retaining and striking an article. In particular, it relates to an attachment for wheelchairs which enables the operator of the wheelchair to participate in a sport such as hockey or skittles which involves firing a ball, puck or other projectile.

It is common for wheelchair users to participate in numerous sports, such as basketball, archery or racing. However, these sports require a high degree of physical strength and coordination and, as a result, many users of wheelchairs may be unable to participate by virtue of their disability.

According to a first aspect of the present invention there is provided an attachment for a wheelchair comprising: a housing which houses ejection means for ejecting a projectile by applying a force to it; guide means for guiding the projectile into the housing; retaining means for retaining the projectile within the housing; and adjusting means for adjusting the force applied by the ejection means to the projectile.

The ejection means may comprise a head which is adapted to strike the projectile. Although the head may be manually operated, the head is preferably driven by an electric motor under the control of the operator.

Thus, a minimum of strength may be required in order to operate the ejection means.

The head may be drawn back against the action of a spring and the motor may be controlled to retain the head in such a drawn back position until a command is given by the operator to eject the projectile (a "fire" command). There may be provided a control unit having a first actuator which operates the ejection means.

There may also be provided a second actuator which operates the adjusting means.

The housing preferably has an opening for receiving the projectile and the guide means may comprise a funnelling member which is positioned adjacent to the opening.

The projectile is preferably made from a ferromagnetic material, or has a ferromagnetic insert.

The retaining means may then comprise a magnetic element which is positioned such that when the projectile enters the opening of the housing, it is attracted to the magnetic element. The retaining means preferably retains the projectile in a position along the path of the head such that when the head is driven in an operative direction it strikes the projectile.

The adjusting means may comprises means for applying a force to the head in a direction away from the operative direction of the head. Preferably, the adjusting means comprises a spring, a first end of which is attached to the head and a second end of which is attached to an adjusting element. The adjusting element may then operate to move the second end of the spring thereby to vary the extension of the spring and to apply a variable force to the head in a direction away from the operative direction of movement of the head. The adjusting element preferably comprises a motor which drives a disc to which the second end of the spring is attached. The motor of the adjusting element is then controlled by the second actuator of the control unit.The adjusting element is preferably driveable between two operative positions which correspond to a strike of maximum and minimum power respectively.

Preferably, the housing comprises mounting brackets to enable the attachment to be secured to the base of a wheelchair.

According to a second aspect of the present invention there is provided a wheelchair having an attachment in accordance with the first aspect of the present invention.

According to a third aspect of the present invention there is provided a unit for propelling an article, the unit comprising: retaining means for retaining the article within the unit; striking means for applying a force to the article; driving means for driving the striking means; and adjusting means for adjusting the force applied by the striking means to the article and comprising adjustment driving means which drives an adjusting element thereby to vary a force applied to the striking means in a direction substantially opposite to the direction in which force is applied to the article by the striking means.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a perspective view of a wheelchair having an attachment for playing a game; Figure 2 shows, in greater detail, the attachment of Figure 1; Figure 3 shows, in schematic form, the components of the attachment shown in Figure 2; Figure 4 is a perspective view of a striking mechanism of the attachment shown in Figure 2.

Figure 5 is a perspective view of an adjusting mechanism of the attachment shown in Figure 2; Figure 6 shows a retaining element of the attachment shown in Figure 2; and Figure 7 shows a circuit diagram for the attachment shown in Figure 2.

Figure 1 shows a wheelchair 2 having an attachment 4 which enables a ball or puck 6 (hereinafter referred to as the "puck") to be fired under the control of the user of the wheelchair. The puck 6 has a metal insert 7 and has a diameter of approximately 8 cm and a depth of approximately 1 cm. The attachment 4 has a control unit 8 for controlling the operation of the attachment 4. Control of the attachment 4 enables a selection of the power of the shot to be made and also a selection of when the ball or puck 6 is to be fired. The attachment 4 has means for retaining the puck 6 so that the operator of the wheelchair can reverse without leaving the puck 6 behind.

The attachment 4 is shown in greater detail in Figure 2. It comprises a housing 10 having an opening 12. The housing 10 is provided with a number of castors 14 which enable the attachment to roll freely on the ground. Although three castors are shown, an alternative number of castors may be provided. The housing 10 has mounting brackets 16 to enable the attachment 4 to be suspended from the base of the wheelchair 2. Units (not shown) may be provided to enable the attachment 4 to be attached to a wide variety of wheelchairs. The housing 10 further comprises a guide funnel 18 to guide the puck 6 to the opening 12. The housing 10 has relatively small height the enable the unit 4 to be suspended beneath the wheelchair 2. The funnel 18 has a wide opening 20 at an end away from the housing 10 and the funnel 18 tappers inwardly towards the opening 12.

The control unit 8 has fire button 11, a pivotable switch 9 for increasing or decreasing the power of the shot, and an LED display 13 to indicate the power level chosen.

Figure 3 shows the components of the attachment 4 in schematic form. A first motor 22 and a second motor 32 are mounted in the housing 10 by mounting bracket (not shown). The first motor 22 is disposed horizontally and has a gearbox 24, the output of which is a vertical shaft 26. The vertical shaft 26 drives a striking element 28 which has a head 30. This assembly constitutes a striking mechanism The second motor 32 is also disposed horizontally and has a gearbox 34, the output of which is a vertical shaft 36. The shaft 36 drives an adjusting element 38 which is connected to the head 30 by means of a spring 40. This assembly constitutes an adjustment mechanism.

A magnetic retaining element 42 is positioned adjacent to the opening 12 and extends across the width of the opening. The element 42 is raised from the base of the housing 10.

The construction of the striking mechanism as shown in greater detail in Figure 4. The motor 22 drives the shaft 26 by means of the gearbox 24. The shaft 26 is connected to a disc 44 which lies in a substantially horizontal plane. The disc 44 has an indentation 46 in its outer periphery and has a downwardly projecting pin 48. A sensor 50 is positioned adjacent the outer circumference of the disc 44 and comprises a switch having a sprung switch pin 52. The switch pin 52 abuts the outer circumference of the disc 44 and is responsive to the presence or absence of the indentation 46.

The striking element 28 is pivoted relatively to the housing 10 at a pivot point 54. The pivot point 54 is not aligned with the axis of a shaft 26. At one end of the striking element 28 there is provided the head 30 and towards the other end of the head 28 there is provided a plate 56. The plate 56 interrupts the path 58 of the pin 48 for some, but not all, angular positions of the striking element 28 with respect to the pivot point 54. The end of the striking element 28 having the plate 56 is also connected to one end of a spring 60, the other end of which is mounted on the housing 10. The path of the head 30 as the striking element 28 rotates about the pivot point 54 is shown at the dotted line 62.

The construction of the adjustment mechanism is shown in greater detail in Figure 5. The motor 32 is connected to the shaft 36 by means of a gearbox 34.

The shaft 36 is connected to the adjusting element 38 which is in the form of a disc having a radial extension 64. The radially outermost end of the extension 64 is connected to one end of the spring 40, the other end of which is connected to the head 30 of the striking element 28. The path of the radially outermost end of the extension 64 is shown at the dotted line 66 and, as can be seen in Figure 5, the paths 62 and 66 do not cross.

The disc of the adjusting element 38 lies in a substantially horizontal plane and has two indentations 68,69 in its outer circumference. Two sensors 70, 72 are provided which each comprises a switch having a respective switch pin. Thus, the sensors 70, 72 are responsive to the presence or absence of the indentations 69 and 68 respectively and are therefore responsive to the angular position of the adjusting element 38.

The construction of the retaining mechanism is shown in greater detail in Figure 6. The magnetic retaining element 42 comprises a substantially horizontal support member 74 on which there is mounted a magnet 76. The support member 74 is raised from the base of the housing 10 by a leg 78. The support member 74 extends across a channel 80, one end of which terminates at the opening 12 of the housing 10. The other end of the channel 80 terminates at an abutment face 82 in the form of a shock absorbent material which is attached to a support 84. The path 62 of the head 30 of the striking element 28 lies in a substantially horizontal plane which passes beneath the plane of the support member 74. The path 62 of the head 30 lies above the plane of the support 84.

The circuitry of the attachment 4 is shown in Figure 7. The circuitry comprises a first circuit portion 86, which controls the first motor 22, a second circuit portion 88, which controls the second motor 32, and a third circuit portion 90 which controls the bar graph LED 13 for displaying the power set for the following shot.

The circuit 86 comprises the motor 22 which is connected, by the shaft 26, to the disc 44. The disc 44 acts upon the striking element 28 by means of the pin 48, and the striking element 48 is connected to the spring 60.

One terminal of the motor 22 is connected to a high voltage line (12 volts) and the other terminal of the motor is connected to earth. A first switch 92 and a second switch 94 are connected in parallel and both switches 92, 94 are positioned between the high voltage line and the corresponding terminal of the motor 22.

Thus, to interrupt the power supply to the motor, both switches 92, 94 must be open. Switch 94 represents the fire button 9 of the control unit 8. Switch 92 is connected to the sensor 50. When the switch pin 52 of the sensor 50 is an extended position, and projects into the indentation 46 on the disc 44, the switch 92 is in an open position.

The second circuit portion 88 comprises the second motor 32. The two terminals of the motor 32 are connected to the high voltage line (12 volts) and earth respectively, by means of the pivot switch 9. The pivot switch 9 has a forward position, a neutral position and a reverse position. In a forward position of the switch 9, the 12 volt line is connected, through a forward interrupter switch 98, to a first terminal 32A of the motor 32. A second terminal 32B of the motor 32 is then connected to earth. Thus, if the forward interrupter switch 98 is in a closed position, then the motor 32 is driven in a forward direction.

In a reverse position of the switch 9, the twelve volt line is connected to the second terminal 32B of the motor 32, and the first terminal 32A of the motor 32 is connected, through a reverse interrupter switch 100, to earth. Thus, if the reverse interrupter switch 100 is in the closed position, then the motor can be driven in a reverse direction.

The second motor 32 acts on the adjusting element 38, to vary is angular position. One sensor 70 of the two sensors 70,72 is connected to the forward interrupter switch 98 and the other sensor 72 is connected to the reverse interrupter switch 100. The sensors 70, 72 correspond to the sensor 50 of the first circuit portion. Thus, if the pin of the sensor 70 is located in the indentation 68 on the adjusting element 38 then the forward interrupter switch 98 will be opened, and as a result the motor will not be able to be driven in a forward direction. This position of the adjusting element therefore corresponds to the maximum forward displacement of the adjusting element 38.If the pin of the sensor 72 is located in the indentation 69 of the adjusting element 38, then the reverse interrupter switch 100 will be open and consequently the motor 32 will not be able to be driven in a reverse direction. This condition of the motor corresponds to the maximum reverse displacement of the adjusting element 38. In this way, the adjustment may be carried out between two limits corresponding to maximum and minimum shot power.

The angular position of the adjusting element 38 is determined by the position of the shaft 36 and this information is fed to a potentiometer VR1 in the third circuit portion 90. The position of the potentiometer VR1 determines how many LED lights are illuminated on a scale on the control unit 8, to provide a visual indication of the power selected for the following shot. The reading from the potentiometer VR1 is fed into an input of the bar graph LED unit to enable operation of the LED unit.

The pivot switch 9, the fire button 11 and the bar graph LED unit 13 together comprise the control unit 8.

The operation of the system will now be described in greater detail. As shown in Figure 1, the attachment 4 is mounted underneath a wheelchair 2. The user of the wheelchairs drives over a puck in order to retrieve it, or alternatively the puck may be received from another player who passed it by aiming it at guide 18. The puck enters the wide opening 20 of the guide funnel 18 and is deflected by the side walls of the funnel 18 into the opening 12 of the housing 10. The puck is then received by the channel 80 (Figure 6) and depending upon the relative speed of the wheelchair and the puck, the puck may strike the abutment face 82.

The abutment face 82 is of a shock absorbent material so that the puck does not bounce off. At this position, there is a magnet 76 located above the puck.

As the puck has a ferromagnetic insert 7 or is itself ferromagnetic, it is attracted to the magnet 76 and is raised from the floor by it. When suspended from the support member 74 of the magnetic retaining element 42, the puck 6 lies in the path 62 of movement of the head 30 of the striking element 28.

The operation of the striking mechanism will be shown with reference to Figure 4. The motor 22 drives the disc 44 in a direction shown by the arrow 45. When the switch pin 52 of the sensor 50 is not located in the indentation 46, the first circuit portion 86 (Figure 7) causes the motor 22 to be driven until such time as the angular position of the disc 44 results in the pin 52 locating the indentation 46. As the disc 44 rotates, the pin 48 follows its path 58. At a certain angular position, the pin 48 strikes the plate 56 on the striking element 28. As the motor 22 continues to drive around, the plate 56 is driven along, causing the striking element 28 to rotate about the pivot point 54.

The spring 60 is thus extended. When the indentation 46 has finally reached the pin 52 of the sensor 50, the pin 48 is located at an edge of the plate 56. In this position, the head 30 is in fully cocked position, ready to fire. Referring to Figure 7, the first switch 92 is then in an open position, and consequently to drive the motor any further, the fire button 11 must be pressed, thereby to complete the circuit. When the fire button 11 is pressed, disc 44 is driven around such that the indentation 46 no longer cooperates with the pin 52. Furthermore, the pin 48 moves out of engagement with the plate 56 thereby causing release of the striking element 28. The spring 60 pivots the striking element 28 about the pivot point 54 which causes the head 30 to be driven towards the puck, which is suspended beneath the support member 74 of the magnetic retaining element 42.As a result of the movement of the disc 44 by pressing the fire button 11, the switch 92 closes and consequently the motor 22 is driven until the head 30 is once more in the fully cocked position.

An adjustment mechanism is also provided for varying the force of the strike on the puck 6. The operation of the adjustment mechanism will be described with reference to Figure 5. The second motor 32 drives the adjusting element 38 which has the extension 64.

The element 38 may be driven in either direction by the motor 32 thereby to vary the extension of the spring 40. The element 38 can be driven in a "forward" direction, as shown in Figure 5, until the pin of the sensor 70 is accommodated within the indentation 68 whereupon the switch 98 is open. This corresponds to a position of minimum extension of spring 40. Similarly, the motor 32 can be driven in "reverse" direction, as shown in Figure 5, until the pin of the sensor 72 is accommodated within the indentation 69 whereupon the switch 100 is open. This corresponds to a position of maximum extension of the spring 40.

The position of the adjusting element 38 represented on the bar graph LED unit 13 to give indication of the force of the strike.

When the fire button 11 is pressed and the head 30 is released from its fully cocked position, the movement of the head 30 towards the puck 6 is restrained by the spring 40. The greater the extension of the spring 40, the more restricted is the speed of advance of the head 30 to the puck 6. Thus, the extension of the spring 40 is used to vary the power of the strike.

Although the specific embodiment of the apparatus described herein utilises electric motors, a manual arrangement could equally be envisaged. However, the provision of electric motors gives rise to the possibility of both simple and light control using the control unit 8 which enables wheelchair users with severe disabilities to use the apparatus. No power supply has been shown in the specific embodiment, although a user of a manual wheelchair would need an associated power supply, such as a 12 volt battery.

However, if the apparatus is to be attached to an electric wheelchair, the power supply for the electric wheelchair may be used to power the apparatus.

The apparatus shown in the drawings uses a magnetic block in order to retain the puck within the housing. However, a number of different alternatives may be considered. Furthermore, the use of a spring acting against the movement of the striking element is also one of a number of solutions to the problem of enabling a variable strength of shot to be played.

The retrieval of the puck by the apparatus shown in the accompanying drawings may be achieved either by driving over the puck, ensuring that the wide opening of the funnel "catches" the puck, or alternatively, the puck may be passed from one player to the other.

However, the present invention may be used for games other than hockey, such as skittles where this method is not appropriate. An alternative retrieval system may comprise a gravity feed system whereby the user of the wheelchair places the puck or ball, or a set of pucks or balls, into a chute which feeds the puck or ball, or the leading puck or ball, to the magnetic retaining element 42 or other retaining device.

Claims

CLAIMS 1. An attachment for a wheelchair comprising: a housing which houses ejection means for ejecting a projectile by applying a force to it; guide means for guiding the projectile into the housing; retaining means for retaining the projectile within the housing; and adjusting means for adjusting the force applied by the ejection means to the projectile. 2. An attachment means as claimed in claim 1, in which the ejection means comprises a head which may be driven, in an operative direction, to strike the projectile. 3. An attachment means as claimed in claim 2, in which the head is driven by an electric motor. 4. An attachment as claimed in claim 3, in which the motor is operated to draw the head back against the action of a spring and to retain the head in such a drawn back position. 5. An attachment as claimed in claim 4, further comprising a control unit having a first actuator which operates the motor. 6. An attachment as claimed in claim 5, in which the first actuator may be operated to release the head from the drawn back position. 7. An attachment as claimed in claim 5 or 6, in which the control unit has a second actuator which operates the adjusting means. 8. An attachment as claimed in any preceding claim, in which the retaining means comprises a magnetic element, the projectile having a ferromagnetic portion. 9. An attachment as claimed in any preceding claim, in which the housing has an opening for receiving the projectile. 10. An attachment as claimed in claim 9, in which the guide means comprises a funnelling member which is positioned adjacent to the opening. 11. An attachment as claimed in claim 9 or 10, when appendant to claim 8, in which the magnetic element is positioned such that when the projectile enters the opening of the housing, it is attracted to the magnetic element. 12. An attachment as claimed in any one of claims 2 to 11, in which the retaining means retains the projectile in a position along the drive path of the head. 13. An attachment as claimed in any one of claims 2 to 12, in which the adjusting means comprises means for applying a force to the head in a direction away from the operative direction of drive of the head. 14. An attachment as claimed in claim 13, in which the adjusting means comprises a spring, a first end of which is attached to the head and a second end of which is attached to an adjusting element. 15. An attachment as claimed in claim 14, in which the adjusting element is operable to move the second end of the spring thereby to vary the extension of the spring so as to apply a variable force to the head in a direction away from the operation direction of drive of the head. 16. An attachment as claimed in claim 15, in which the adjusting element comprises a motor which drives a disc to which the second end of the spring is attached. 17. An attachment as claimed in any preceding claim in which the housing comprises mounting brackets to enable the attachment to be secured to the base of a wheelchair. 18. A wheelchair having an attachment in accordance with any preceding claim. 19. A unit for propelling an article, the unit comprising: retaining means for retaining the article within the unit; striking means for applying a force to the article; driving means for driving the striking means; and adjusting means for adjusting the force applied by the striking means to the article and comprising adjustment driving means which drives an adjusting element thereby to vary a force applied to the striking means in a direction substantially opposite to the direction in which force is applied to the article by the striking means. 20. An attachment for a wheelchair substantially as described herein, with reference to and as shown in the accompanying drawings. 21. A wheelchair having an attachment as claimed in claim 20. Amendments to the claims have been filed as follows CLAIMS

1. An attachment for a wheelchair having a seat, the attachment comprising: a housing which houses ejection means for ejecting a projectile by applying a force to it, the housing having support means for supporting at least part of the housing beneath the seat; guide means for guiding the projectile into the housing; retaining means for retaining the projectile within the housing; and adjusting means for adjusting the force applied by the ejection means to the projectile.

2. An attachment means as claimed in claim 1, in which the ejection means comprises a head which may be driven, in an operative direction, to strike the projectile.

3. An attachment means as claimed in claim 2, in which the head is driven by an electric motor.

4. An attachment as claimed in claim 3, in which the motor is operated to draw the head back against the action of a spring and to retain the head in such a drawn back position.

5. An attachment as claimed in claim 4, further comprising a control unit having a first actuator which operates the motor.

6. An attachment as claimed in claim 5, in which the first actuator may be operated to release the head from the drawn back position.

7. An attachment as claimed in claim 5 or 6, in which the control unit has a second actuator which operates the adjusting means.

8. An attachment as claimed in claim 6 or 7, in which after release of the head from the drawn back position, the motor is automatically operated to draw the head back, again, to the drawn back position.

9. An attachment as claimed in any preceding claim, in which the retaining means comprises a magnetic element, the projectile having a ferromagnetic portion.

10. An attachment as claimed in any preceding claim, in which the housing has an opening for receiving the projectile.

11. An attachment as claimed in claim 10, in which the guide means comprises a funnelling member which is positioned adjacent to the opening.

12. An attachment as claimed in claim 10 or 11, when appendant to claim 9, in which the magnetic element is positioned such that when the projectile enters the opening of the housing, it is attracted to the magnetic element.

13. An attachment as claimed in any one of claims 2 to 12, in which the retaining means retains the projectile in a position along the drive path of the head.

14. An attachment as claimed in any one of claims 2 to 13, in which the adjusting means comprises means for applying a force to the head in a direction away from the operative direction of drive of the head.

15. An attachment as claimed in claim 14, in which the adjusting means comprises a spring, a first end of which is attached to the head and a second end of which is attached to an adjusting element.

16. An attachment as claimed in claim 15, in which the adjusting element is operable to move the second end of the spring thereby to vary the extension of the spring so as to apply a variable force to the head in a direction away from the operation direction of drive of the head.

17. An attachment as claimed in claim 16, in which the adjusting element comprises a motor which drives a disc to which the second end of the spring is attached.

18. An attachment as claimed in any preceding claim in which the support means comprises mounting brackets to enable the attachment to be secured to the base of the wheelchair.

19. A wheelchair having an attachment in accordance with any preceding claim.

20. A unit for propelling an article, the unit comprising: retaining means for retaining the article within the unit; striking means for applying a force to the article; driving means for driving the striking means; and adjusting means for adjusting the force applied by the striking means to the article and comprising adjustment driving means which drives an adjusting element thereby to vary a force applied to the striking means in a direction substantially opposite to the direction in which force is applied to the article by the striking means.

21. An attachment for a wheelchair substantially as described herein, with reference to and as shown in the accompanying drawings.

22. A wheelchair having an attachment as claimed in claim 21.