GB2077896A

GB2077896A - Improvements in actuating systems

Info

Publication number: GB2077896A
Application number: GB8014924A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-05-03
Filing date: 1980-05-03
Publication date: 1981-12-23

Abstract

The present invention relates to actuating systems using a sealed liquefied gas container in which the gas is typically carbon dioxide. Means are provided for releasing the gas in response to various signals and using it to power a jack for moving a load. The jack shown is supplied with gas from a liquefied gas container having a piercing member for releasing the gas into a pipe (34). The gas enters an annular chamber 37 and causes relative movement between a piston (32) and a cylinder (30). This movement causes links (26), which are pivoted to the cylinder (30) and to the piston rod (33), to lift a load- engaging bridge piece (24) away from a base (25). <IMAGE>

Description

SPECIFICATION Improvements in actuating systems The present invention relates to actuating systems which use a liquified gas typically stored in a cylindrical gas container as the source of energy, and is particularly applied to lifting and other actuating devices where significant force and work are required, such as in car jacks for raising part of the vehicle from the ground: power tools, and emergency and safety systems for opening or closing valves, doors, windows and other devices.

In many situations, in particular cars and commercial vehicles, there is not generally a convenient source of power available for operating ancillary equipment, such as jacks and power tools, and such functions rely on manual effort.

Normally, jacks are mechanical or hydraulic and use manual effort to provide the work to lift the vehicle. Mechanical car jacks have a low efficiency which is used as an irreversibility feature to prevent the jack retracting until further manual effort is applied in the reverse direction.

In hydraulic systems a cylinder is fed by means of a pump, generally operated by hand or foot, and inadvertent retraction of the jack is prevented by sealing the fluid in the cylinder means of a valve.

The present invention seeks to provide an actuating system where the energy is provided by a compressed gas derived from a liquefied gas container and allows for the controllable extension and retraction of a jack under a prescribed load.

One embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which Figure 1 shows a liquified gas container and associated control valves, Figure 2 shows a jack for cars or commercial vehicles, Figure 3 a typical relationship between gas pressure and jack extension, and Figure 4 a mechanical latching mechanism.

Figure 1 shows a liquified gas container 10, the neck of which is inserted into socket 11, and being retairied in the housing 12, which is screwed onto transfer body 13. Housing 12 is knurled on the outside and acts as a handle. Housing 12 is rotated causing the end of the gas container 10 to be pierced by tube 14 to allow pressurised gas to be passed to valve seat 1 5. Valves 1 6 and 17 are initially closed onto seats 1 5 and 18. By manual rotation of the screwed member 1 9 via knurled knob 20, valve 1 6 is opened allowing pressurised gas to pass to connection 21 and hence to the jack on Figure 2 via pipe 34. Connection 21 may be replaced by a quick release connector to allow operation of a range of accessories.

The jack in Figure 2 is seen to consist of an upper bridge piece 24 in contact with load W, and a similar lower bridge piece 25 normally in contact with the ground or some earthed member.

Connected to each bridge piece are four links 26, two on either side, by means of riveted pivot pins 26a.

Adjacent links are inter-connected by means of ge r teeth 28 formed on the ends of the links to ensure that the links move in symmetry to constrain the upper bridge piece to move in an essentially straight line path. The outer ends of the left hand set of links 26 are connected via pivot pin 29 to the cylinder 30 via end cap 31. The right hand set of links 26 are connected to pin 29, and hence piston 32, via the actuator piston rod 33 of a gas operated actuator. End caps 29 and 35 and cylinder 30 are held together by bolts 42 and nuts 43.

In operation, gas via valve 16, Figure 1, passes via pipe 34, Figure 2, and hole 36 to annulus 37 on the rod side of the piston causing the distance between pins 29 and 29a to reduce, thereby raising load W. The opposite side of piston 32 is vented to atmosphere via hole 31 a. The rate at which the load is raised is regulated by rotation of knurled knob 20, Figure 1. To lower the load, valve 1 6 is closed and knurled knob 23 rotated to allow gas to escape to atmosphere via valve 1 7 and hole 17a, Figure 1.

A particular advantage of this construction will be seen with reference to Figure 3 which shows the typical relationship between the pressure required at the gas cylinder to support a constant load W on the bridge piece and the displacement of bridge piece 24, Figure 2, ie extension of jack in a vertical direction. The reduction in pressure with increase in lift, which results from the characteristics of the link mechanism described previously, enables the average operating pressure of the gas actuator to be much higher than with non link arrangements, resulting in an actuator of much lower swept volume. Also, the gas actuator is acting in tension and therefore can be of light construction.

A further important feature of the present invention is that the gas cylinder is situated and acts at right angles to the load W, Figure 2, which it is required to overcome, and a low installed height is obtained. This is important in many applications, in particular vehicle jacks, since when changing a tyre the suspension is at its lowest height due to the tyre being flat.

Another feature of the present invention is that a greater pressure than that required to lift the load W, figure 2, causes piston 32 to move against the cylinder end face 38 to provide a residual force to resist actuator deflection from external loads. If required, a simple mechanical latching device, Figure 4, could be incorporated to provide mechanical resistance to jack retraction at maximum or part extension positions. Figure 4 shows on arrangement using two links 39 which incorporate slots 40 to engage with actuator pin 29a. These can be moved into position either by gravity or by means of a spring. The links 39 are shown joined together by means of a cross member 41 to enable the links to be lifted by the operator's foot to provide disengagement.

The normal mode of failure of seals is that a gradual leak develops, rather than a catastrophic rupture, and therefore whilst a latching device may be necessary to ensure that the jack does not retract due to leakage of a seal, further gas can be introduced to slightly raise the actuator enabling links 39 to be disengaged from pin 29a by the operator's foot, and allow a controlled retraction of the actuator. It is possible by repositioning the links 26, Figure 2, to allow these to "over centre" in the maximum lift position to make the jack irreversible, but in this arrangement the gas actuator is made double acting allowing a force to be applied to piston 32 to move links 26 from the "over centre" position.

Claims

1. An actuating system which comprises a sealed liquified gas container, containing a high vapour pressure gas such as carbon dioxide, and a piercing member incorporates a,small, thin walled tube or spike which is caused to pierce the liquified gas container in response to a prescribed signal, allowing the resulting gas pressure to operate an actuator.

2. An actuating system which comprises a liquified gas container as in Claim 1 and a piercing member incorporating a small, thin, walled tube or spike which is caused to pierce the liquified gas container in response to a prescribed signal, allowing the resulting pressure to cause a column of air in a pipe or vessel to produce a loud acoustic emission.

3. An actuating system, as claimed in Claims 1 and 2, comprising a liquified gas container and a movable piercing member incorporating a small, thin walled tube or spike and a spring retained in its compressed state until released in response to a prescribed signal to allow the spring to release its energy to cause the sealed liquified gas container to be pierced allowing the resulting gas pressure to operate an actuator.

4. An actuating system, as claimed in Claim 3, comprising a liquified gas container and a piercing member incorporating a small, thin walled tube or spike and a spring retained in its compressed state until released in response to a prescribed signal which allows the spring to release its energy, to cause the sealed liquified gas container to be pierced allowing the resulting gas pressure to cause a column of air in a pipe or vessel to produce an acoustic emission.

5. An actuating system, as claimed in Claims 3 and 4, in which the said spring is retained in compression by a low melting point alloy in the form of a soldered joint or retaining member acting in tension, shear or compression so as to release the energy from the spring when a prescribed temperature in the region of the low melting point alloy has been reached.

6. An actuating system, as claimed in Claims 1 and 2, in which a member manufactured from a shape memory effect alloy of the type which produces a metallurgical phase change at a prescribed temperature expands or contracts at the prescribed temperature to cause the liquified gas container to be pierced.

7. An actuating system, as claimed in Claims 1 and 2, in which a thermal wax type actuator comprising a volume of high expansion fluid contained in a chamber from which extends a moving piston or extensible bellows or capsule, such that at a prescribed temperature the liquified gas container is pierced releasing the gas.

8. An actuating system, as claimed in Claims 3 and 4, in which the said compressed spring is retained in its compressed position by a latching or toggle-type mechanism arranged to substantially reduce the required force necessary to release the energy from the comprssed spring.

9. An actuating system, as claimed in Claims 3 4 and 8, in which an electrical solenoid is energised in response to a prescribed signal to release the said latching or toggle mechanism to allow the compressed spring to release its energy.

10. An actuating system, as claimed in Claims 3, 4 and 8 in which the said latching or toggle mechanism is released by means of a mechanical, hydraulic, pneumatic or manual input.

11. A jack as claimed in 1,2,3,4,7 and 10 in which the jack is double acting.

11. An actuating system, in which a liquified gas container as in Claim 1 is moved into engagement with a piercing member incorporating a small, thin walled tube or spike which is caused to pierce the liquified gas container in response to a prescribed signal allowing the resulting gas pressure to operate an actuator.

12. An actuating system in which a piercing member incorporating a small, thin walled tube or spike is moved to pierce the liquified gas container as in Claim 1 in response to a prescribed signal allowing the resulting gas pressure to operate an actuator.

13. An actuating system in which a liquified gas container as in Claim 1 is moved into engagement with a piercing member incorporating a small, thin walled tube or spike, which is caused to pierce the liquified gas container in response to a prescribed signal allowing the resulting gas pressure to cause a column of air in a pipe or vessel to produce a loud acoustic emission.

14. An actuating system in which a piercing member incorporating a small, thin walled tube or spike is moved to pierce the liquified gas container as in Claim 1 in response to a prescribed signal allowing the resulting gas pressure to cause a column of air in a pipe or vessel to produce a loud acoustic emission.

1 5. An actuating system, as claimed in Claim 8, in which the release of the toggle or latching mechanism is caused by the relative displacement between the toggle or latching mechanism and a fixed or moving member, in which the relative motion may be parallel to, are at an angle at, the toggle or latching mechanism to release the energy from the compressed spring.

1 6. An actuating system, as claimed in Claims 3, 4, 8 and 13, where the liquified gas container and its piercing and release mechanism is contained in a housing which is retained to a fixed or moving member by means of a lock mechanism either of the type requiring a key or a combination of digits.

1 7. A jack comprising a fluid powered actuator having the fixed and moving ends connected to the load transmission linkage such that movement of the actuator caused the load reaction members connected to the linkage, and hence the load, to move substantially at right angles to the axis of the actuator.

18. A jack, as claimed in Claim 17, which is powered by pressure derived from a liquified gas container, as hereinbefore described in Claim 1.

1 9. A jack as hereinbefore described in Claims 1 7 and 18 in which an adjustable mechanical locking member is provided to prevent the actuator extending and thereby preventing the load from lowering inadvertently.

20. A jack as described in Claims 1 7, 18, and 19, in which an adjustable mechanical locking member is provided to prevent the actuator extending and in which the load on the jack is reacted between the actuator body and the piston rod or its associated linkage.

21. A jack as hereinbefore described in 17, 18, 1 9 and 20, in which an adjustable locking member is provided to enable adjustment of jack extension.

22. A jack as hereinbefore described in Claims 18, 19, 20 and 21, in which the valve causing pressurised gas to be delivered to the actuator and exhausted trom the actuator is operated remotely by means of a cable or rod.

23. A jack as claimed in Claims 19,20,21 and 22, in which the locking member, hereinbefore described, is operated remotely by a rod or similar mechanical member.

24. An actuator as claimed in Claims 19, 20, 21,22 and 23 in which the input mechanism to the cable or rod operating the control valve, hereinbefore described in Claim 22, is connected to the rod which operates the mechanical locking device, as hereinbefore described in Claim 1 9.

25. An actuator,as hereinbefore described in Claim 1, in which the stationary part of the actuator is provided with a multiplicity of rolling elements to provide low frictional resistance with the ground or other earthed member.

26. An actuator as claimed in Claim 25, in which a multiplicity of extension members are fitted to the fixed and moving parts of the actuator so as to limit the relative displacement between the said fixed and moving parts and thereby provide stability of the load.

27. An actuator as described in Claims 25 and 26, in which an endless belt is interposed between the rolling elements and the earthed member. The earthed member being guided by further rolling elements.

28. An actuating system as hereinbefore described in Claims 1,11,12,17,18,19,20,21, 22, 23, 24, 25, 26 and 27 in which the pressure to the actuator is regulated to a substantially constant selectable value above atmospheric pressure and in which the selected pressure can be varied.

29. An actuating system as claimed in Claims, 1,11,12,17,18, 19,20,21,22,23,24,25,26, 27 and 28 in which provision is made in the valve to cut off the supply of gas from the pressurised gas container.

30. An actuating system as claimed in Claims 2,3,4,5,6,7,8,9,10,13, 14,15, and 16in which pressure to the vibrating or oscillating member hereinbefore described is regulated to a substantially constant selectable value above atmospheric pressure.

31. An actuating system as claimed in Claims 2,3,4,5,6,7,8,9,10,13, 14,15, 16 and 30 in which provision is made in the valve to cut off the supply of gas from the pressurised gas container.

32. An actuator as claimed in Claims 1,28 and 29 in which an output member is rotated by the said actuator to form a power tool.

33. An actuator which is pressurised by gas derived from a liquified gas container as in Claim 1 to provide resistance to extension or contraction for the purpose of human body exercise.

34. An actuator as claimed in Claim 33 where pressure is reacted via a valve to substantially maintain a selected relationship between applied force and displacement.

35. An actuator as claimed in Claims 33 and 34 where the said valve is directly connected to the actuator.

36. An actuator as claimed in Claims 33, 34 and 35 where the said valve is transferable between the piston rod and the cylinder to enable the actuator to provide a displaceable resistance as required to apply tensile and compressive force.

37. An actuator as claimed in Claims 33, 34, 35, and 36 where extension members in the form of a linkage, mechanism or structure are attached to the actuator to facilitate the exercising of prescribed parts of the human body.

38. A car jack substantially as hereinbefore described with reference to and as shown in Figures 1 82 of the accompanying drawings.

39. An internal door closer substantially as hereinbefore described with reference to and as shown in Figure 3 of the accompanying drawings.

40. An external door closer substantially as hereinbefore described with reference to and as shown in Figure 4 of the accompanying drawings.

41. A door closer incorporating an audible alarm substantially as hereinbefore described with reference to and as shown in Figure 5 of the accompanying drawings.

42. A valve actuator substantially as hereinbefore described with reference to and as shown in Figure 6 of the accompanying drawings.

43. A fire alarm substantially as hereinbefore described with reference to and as shown in Figure 7 of the accompanying drawings.

44. A person attack alarm substantially as hereinbefore described with reference to and as shown in Figure 8 of the accompanying drawings.

45. A low temperature alarm substantially as hereinbefore described with reference to and as shown in Figure 9 of the accompanying drawings.

46. An intruder alarm substantially as hereinbefore described with reference to and as shown in Figure 10 of the accompanying drawings.

47. A solenoid operated actuator substantially as hereinbefore described with reference to and as shown in Figure 11 of the accompanying drawings.

48. A lifting pad substantially as hereinbefore described with reference to and as shown in Figure 12 of the accompanying drawings.

49. A power tool substantially as hereinbefore described with reference to and as shown in Figure 13 of the accompanying drawings.

50 An exercising device substantially as hereinbefore described with reference to and as shown in Figure 14 of the accompanying drawings.

New claims or amendments to claims filed on Superseded claims: 1 to 50 New or amended claims: CLAIMS

1. An actuating system which comprises a sealed liquified gas container, containing a high vapour pressure gas such as carbon dioxide, and a piercing member incorporating a small, thin walled tube or spike which is caused to pierce the liquified gas container in response to a prescribed signal, allowing the resulting gas pressure to operate an actuator.

2. An actuating system in which a piercing member incorporating a small, thin walled tube or spike is moved to pierce the liquified gas container as in Claim 1 in response to a prescribed signal allowing the resulting gas pressure to operate an actuator.

3. A jack comprising a fluid powered actuator having the fixed and moving ends connected to the load transmission linkage such that movement of the actuator causes the load reaction members connected to the linkage, and hence the load, to move substantially as right angles to the axis of the actuator.

4. A jack as claimed in Claim 17, which is powered by pressure derived from a liquified gas container, as hereinbefore described in Claim 1.

5. A jack, as hereinbefore described in Claims 3 and 4 in which a mechanical locking member is provided to prevent the actuator extending and thereby preventing the load from lowering inadvertently.

6. A jack, as described in Claims 3,4 and 5, in which the adjustable mechanical locking member is provided to prevent the actuator extending and in which the load on the jack is reacted between the actuator body and the piston rod or its associated linkage.

7. A car jack substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

8. An actuating system as claimed in 1.2, 3 and 4 for opening and closing doors, windows, valves and similar devices in an emergency such as a fire or other hazardous situation.

9. An actuating system as claimed in Claimsl, 2, 3 and 4 the output member of which actuates a tool such as a spanner, forming tool, cutting tool, piercing tool or bending tool.

10. Ajack as claimed in 1,2,3,4and7 in which the linkage hereinbefore described is caused to "overcentre" in the maximum lift position to make the jack irreversible until a further signal is applied.