GB2505087A

GB2505087A - An adjusting means for a torsion spring

Info

Publication number: GB2505087A
Application number: GB201316012A
Authority: GB
Inventors: Jonathan Martin Michaelis
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-09-09
Filing date: 2013-09-09
Publication date: 2014-02-19
Anticipated expiration: 2033-09-09
Also published as: GB201316012D0; GB2505087B

Abstract

A torsion spring adjusting means is provided. The adjusting means comprises an adjusting screw 6 that moves a brace 8 which contacts a lug 11 attached to a spring holder 9 to increase or decrease torsion on a spring inside the spring holder 9 that applies torque to a mechanism.

Description

ADJUSTABLE TORSION SPRING

The present invention relates to an adjustable torsion spring. More particularly, the adjustable torsion spring used to assist people when they are lilting an item such as cutlery or a pointer using a handle which is part of a mechanism rotating about a horizontal axis or when such a mechanism rotating about a horizontal axis is left to lilt itself under the action of the spring.

People with physical impairments such as weak arms or severe intention tremor or ataxia often use assistive devices to enable them to perform tasks such as feeding themselves or accessing a computer. For example, a handle may be attached to a base via rotational dampers that absorb and smooth out tremors as the person moves the handle so that a spoon attached to the free end of the handle moves between a plate and their mouth. A spring can be used to assist the lifting action or to lift the spoon automatically if they let go of the handle. The weight of the user's arm, where they hold the handle, the degree of damping in the mechanism, the weight of the item attached to the free end of the handle and any additional attachments such as more accessible angle-adjustable handles all affect how much lifting torque is required from the action of the spring. Similarly a device working on similar principles but using electric motor power pulling on a rope to bring the handle down, releasing the rope to allow a damped sprung mechanism to lift the handle also requires the torque applied by the spring to be adjusted if the spoon is swapped for a heavier object such as a sandwich holder or a shaver attachment.

Typically, people find the instruction steps required to adjust the torsion in the counter balance or lifting spring too complex to follow. As a result, necessary adjustments are not made and people become unable to use the equipment as their circumstances change or do not use it to its full potential. If the instructions steps are followed incorrectly or in the wrong order the spring or other parts of the mechanism can be broken. If reverse torque is applied to the spring it can break or be weakened and break later. The steps required to adjust the spring are: 1. loosen screws holding the outer casing of the spring mechanism; 2. remove a screw used as a stop for height adjustment; 3. lift the handle all the way up to the vertical and over to the opposite side; 4. note the angle the handle is being held at on this other side whilst 5. retightening the screws holding the outer casing of the spring mechanism; 6. bring the arm up to the vertical and back over to the side it is to be used on; 7. refit and adjust the screw limiting the movement to the correct height for the user; 8. use the device and see if the degree of lift is as required; 9. repeat the whole process but change the angle in step 4 if the degree of lift is not as desired so that the amount of torsion in the spring is increased or decreased when the handle is in the position it will be used. It is a process of trial and error.

Other attachments such as additional adjustable handles may need to be moved or removed and refitted to allow this process. In the case of the device that uses a motor pulling on ropes to bring the arm down, additional steps are required: detaching and reattaching the ropes.

The invention described herein provides a means for easy adjustment of a torsion spring by turning a single screw. A typical application is a device to enable people with movement impairments to feed themselves or perform other functions. The invention provides the following features: * A torsion spring with one end attached to a mechanism so that it turns about an axis as the mechanism is rotated about that axis.

* A spring holder connected to the other end of the spring.

* A cover that contains the spring holder and spring within which the spring holder can be rotated.

* A brace that can be moved inside the cover so that it rotates the spring holder.

* An adjusting screw in one side of the cover that moves the brace when it is tightened or loosened.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying Figures, in which: Figure 1 -General view of a rotatable assembly.

Figure 2 -View of the inside of a cover sub-assembly.

Figure 3 -General view of a rotatable assembly with the cover sub-assembly removed.

Figure 4 -General view of a rotatable assembly with the cover sub-assembly and the spring holder removed.

Figure 5 -General view of a rotatable assembly with the cover sub-assembly, the spring holder and the spring removed.

Figure 6 -General view of a rotatable assembly with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to a position to apply relatively high torsion to the spiral spring.

Figure 7 -General view of a rotatable assembly with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to a position to apply relatively low torsion to the spiral spring.

Figure 8 -General view of a rotatable assembly with the handle vertical with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to the low torsion position with the spring holder just disengaged from the brace and thus with no torsion in the spiral spring.

Figure 9 -General view of a rotatable assembly set up for use on the opposite side from the previous figures with the handle vertical with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to the low torsion position with the spring holder just disengaged from the brace and thus with no torsion in the spiral spring.

Figure 1 shows a rotatable assembly. A handle 1 is attached to a horizontal axle within bearings fixed to a bracket 2 which in turn is fixed to the bearings of a vertical axle fixed to a base 3. An up-stop screw 4 limits upward movement of the handle when it hits the inside of the bracket. A cover sub-assembly 5 contains an adjustable spring mechanism with an adjusting screw 6. Screws 18 hold the cover sub-assembly to the bracket 2.

Figure 2 shows the inside of a cover sub-assembly. The adjusting screw 6 is retained axially in a cover 7. The adjusting screw is turned to move a brace 8 along its axis. The brace has shaped outer corners to allow maximum travel one way before it hits the inside of the cover.

Figure 3 shows a rotatable assembly with the cover sub-assembly removed. A spring holder 9 has a slot 10 to hold one end of a spiral spring. A lug 11 fixed to the spring holder engages with the brace in the cover sub-assembly when it is fitted to stop it rotating. With the cover sub-assembly removed the spring holder is free to rotate with no torsion on the spiral spring.

Figure 4 shows a rotatable assembly with the cover sub-assembly and the spring holder removed. A spiral spring 12 has an inner leg 13 which engages with the end of the horizontal axle 14 which rotates as the handle 1 moves up and down. The spiral spring has an outer leg which is held in place in a slot in the spring holder when the spring holder is fitted. Thus when the spring holder and cover sub-assembly are fitted, as the handle moves down, torsion in the spiral spring increases. The spiral spring is fitted different ways round for left and right handed uses Figure 5 shows a rotatable assembly with the cover sub-assembly, the spring holder and the spring removed. The horizontal axle 14 which rotates with the handle 1, has a slot 16 that engages with the spiral spring when it is fitted. The slot has rounded edges to avoid contact with the spiral spring where the inner leg bends sharply as this is a weak point in the spring.

Figure 6 shows a rotatable assembly with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to a position to apply relatively high torsion to the spiral spring. The adjusting screw 6 has been tightened to move the brace 8 to the left as shown pushing on the lug 11 to turn the spring holder 9 anti-clockwise thus increasing the torsion in the spiral spring.

Figure 7 shows a rotatable assembly with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to a position to put relatively low torsion in the spring. The adjusting screw 6 has been loosened to move the brace 8 to the right as shown allowing the spring holder 9 to turn clockwise thus decreasing the torsion in the spiral spring.

Figure 8 shows of a rotatable assembly with the handle vertical with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to the low torsion position with the spring holder just disengaged from the brace and thus with no torsion in the spiral spring. As the handle 1 is lifted there is less torsion in the spring until with the handle vertical and the adjusting screw 6 adjusted to the weakest setting, the lug 11 just becomes disengaged from the brace 8 and no torque at all is exerted on the spiral spring. This enables easy assembly of the device and conversion between right and left handed use. The up-stop screw is fitted after this assembly. A down-stop screw 17 can also be fitted and adjusted to limit downward movement of the handle when it impacts with the inside of the bracket 2.

Figure 9 shows a rotatable assembly set up for use on the opposite side from the previous figures with the handle vertical with the cover and screws not shown so that the brace and adjusting screw are visible -adjusted to the low torsion position with the spring holder just disengaged from the brace and thus with no torsion in the spiral spring. Conversion between right and left handed use requires removal of the spiral spring from the spring holder 9, flipping it over to change between effective right and left hand wound modes and refitting it.

The spring holder and spiral spring sub-assembly is then fitted onto the horizontal axle so that when the cover sub-assembly is filled, the lug 11 is the correct side of the adjusting screw 6 so that tightening the adjusting screw increases the torque exerted on the spiral spring as the brace 8 moves to the left as shown. The brace is double-ended to allow for use in both right and left hand modes in this way. The same cover sub-assembly can thus be used for both left and right handed use with it being modified and with it fitted on the same way round. The down-stop screw 17 and the base 3 are shown on the opposite sides from the previous figures.

There is clearance between the spring holder 9 and the cover sub-assembly 5 to allow rotation. Any torsion in the spring keeps the lug 11 in contact with the brace 8.

In the embodiment shown, the torsion spring is a separate part from the spring holder and lug 11 sub-assembly. The invention applies equally to an arrangement wherein one leg of the torsion spring is shaped so that it connects directly with the brace 8 without the need for the connecting parts.

In the embodiment shown, the brace moves directly along the axis of the adjusting screw.

The invention applies equally to other ways of connecting the brace and the adjusting screw.

In the embodiment shown, the maximum torque on the spring with the handle 1 at its lowest position and the adjusting screw 6 at its tightest is within the design limits of the spring for infinite fatigue life. The invention applies equally to other arrangements that might reduce the life of the spring.

In the embodiment shown, with the adjusting screw 6 at the weakest position and the handle 1 vertical, the lug 11 is just disengaged from the brace 8. The invention applies equally to other arrangements with torsion on the spring through greater and lesser ranges of travel.

As the handle 1 is lowered from the vertical position towards the horizontal the torque that its weight and the weight of items attached to it apply increases. The counter balancing torque of the spring also increases. In a specific embodiment of the invention, the spring is designed so that with the adjusting screw 6 adjusted to the weakest setting, the increase in torque of the spring as the handle is lowered roughly matches the increase in torque applied by the weight of the handle and other items achieving a matched counter balance effect in all positions so that the handle neither lifts nor falls when it is not touched or being moved under external power.

In the embodiment shown, the spring is a spiral spring. The invention applies equally to other types of torsion spring though some types require a different left or right hand wound spring to be fitted for left or right handed use.

In the embodiment shown, the torsion spring applies torque around a horizontal axis in order to provide a lifting force. The invention applies equally to applying a force downwards or to applying torque around non-horizontal axes.

In the embodiment shown, the adjusting screw 6 and stop screws 4 and 17 can all be turned using the same common tool but cannot be turned accidentally by hand. The invention applies equally to screws that can be turned by hand or that require the use of a more specialist tool or different tools.

In a further embodiment of the invention, there is a means for adjusting the relative angular displacement of the slot 10 to the lug 11 in the spring holder 9. This enables adjustment of the range of torque that can then be applied by turning the adjusting screw once the cover sub-assembly is fitted.

In a specific embodiment of the invention, a damping means is used to smooth out movements of the handle.

In a further specific embodiment of the invention, the damping is provided using rotational viscous dampers.

In the embodiment shown, the complete adjustable torsion spring assembly is compatible with equipment without this feature that is already in use and can thus be retro-fitted. It is compatible for both right and left handed modes as shown in figures 8 and 9 with no change to the cover sub-assembly and no need to fit it the other way up because the brace 8 is double-ended. The bracket 2 has three holes for the screws 18 to hold the cover 5 in place.

The cover can thus only be filled the way round shown or at 120 and 240 degrees to it, not degrees. So it cannot be easily fitted the other way up. Keeping filling of the cover sub-assembly always the same way round keeps right to left handed conversion by a technician simpler to understand. The invention applies equally to other arrangements.

Claims

CLAIMS: 1. A torsion spring adjusting moans comprising: a torsion spring with one end attached to a mechanism so that it turns about an axis as the mechanism is rotated about that axis; a spring holder connected to the other end of the spring; a cover that contains the spring holder and spring within which the spring holder can be rotated; a brace that can be moved inside the cover so that it rotates the spring holder; an adjusting screw in one side of the cover that moves the brace when it is tightened or loosened; wherein turning the adjusting screw moves the brace to turn the spring holder to adjust the torsion in the spring.
2. A torsion spring adjusting means as claimed in claim 1, wherein the torsion spring is a spiral spring with one end connected to an axle that rotates as a mechanism rotates and the other end connected to a spring holder.
3. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the spring holder has a lug that connects with a brace so that movement of the brace turns the spring holder to adjust the torsion in the spring.
4. A torsion spring adjusting means as claimed in claim 1, wherein the torsion spring has a shaped leg which is an integral part of it that acts as the lug to engage directly with the brace.
5. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the brace moves directly along the axis of the adjusting screw as it is turned.
6. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the brace is shaped to allow increased travel within the cover.
7. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the brace is double-ended.
8. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the axis of rotation of the torsion spring is horizontal and a component of the movement of the mechanism is vertical.
9. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the torsion in the spring cannot be adjusted using the adjusting screw beyond a level that would limit the life of the spring.
10. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein at the lowest torsion selling, the torsion in the spring roughly balances the torque applied by the weight of the assembly it is counter balancing in all positions within which it operates.
11. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the mechanism is damped to smooth movements.
12. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the mechanism is a device to enable people with movement impairments to perform functions independently.12. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the mechanism can be retro-titted to existing equipment in use not yet fitted with the mechanism.Amendments to the claims have been filed as follows CLAIMS: 1. A torsion spring adjusting means comprising: a spring holder connected to an end of a torsion spring; a cover that contains the spring holder and spring within which the spring holder can be rotated; a brace that can be moved inside the cover so that it rotates the spring holder; and an adjusting screw in one side of the cover that moves the brace when it is tightened or loosened; wherein turning the adjusting screw moves the brace to turn the spring holder to adjust the torsion in the spring.2. A torsion spring adjusting means as claimed in claim 1, wherein the torsion spring is a spiral spring with one end connected to an axle that rotates as a mechanism rotates and the other end connected to a spring holder.3. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the spring holder has a lug that connects with a brace so that movement of the brace turns the spring holder to adjust the torsion in the spring.4. A torsion spring adjusting means as claimed in claim 1, wherein the torsion spring : * has a shaped leg which is an integral part of it that acts as the lug to engage directly with the brace.5. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the brace moves directly along the axis of the adjusting screw as it is turned.6. A torsion spring adjusting means as claimed in anyone of the preceding claims, * wherein the brace is shaped to allow increased travel within the cover.7. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the brace is double-ended.8. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the axis of rotation of the torsion spring is horizontal and a component of the movement of the mechanism is vertical.9. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the torsion in the spring cannot be adjusted using the adjusting screw beyond a level that would limit the life of the spring.10. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein at the lowest torsion setting, the torsion in the spring roughly balances the torque applied by the weight of the assembly it is counter balancing in all positions within which it operates.11. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the mechanism is damped to smooth movements.12. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the mechanism is a device to enable people with movement impairments to perform functions independently.
13. A torsion spring adjusting means as claimed in any one of the preceding claims, wherein the mechanism can be retro-fitted to existing equipment in use not yet fitted with the mechanism.