GB2481803A

GB2481803A - Combined air compressor and hose reel for driving a pneumatic jack having a pivotable load engaging attachment device used for leveling a caravan

Info

Publication number: GB2481803A
Application number: GB1011288.6A
Authority: GB
Inventors: Colin Walker
Original assignee: AXEUM Ltd
Current assignee: AXEUM Ltd
Priority date: 2010-07-05
Filing date: 2010-07-05
Publication date: 2012-01-11
Also published as: GB201011288D0

Abstract

A drive apparatus 12 comprises a body, which may be the frame 18 of an air compressor 22 and a hose deployment device, which may be a reel 30. The drive apparatus may be used with an air jack 14 to which it is connected by hose 36. The load platform 38 of air jack 14 may be provided with an attachment device (80 fig. 7) for engaging a load to be raised (100 fig 7). The attachment device (80 fig. 7) comprises a spacer part (74 fig 7) to rest on the load platform 38 and a body or support (82 fig 7) resting on the spacer part (74 fig 7) via a spigot (72 fig 7) engaging a hole in the load platform 38 and pivotable relative to the spacer part (74 fig 7) about an axis (94 fig 7). The body (82 fig 7) is the means by which the attachment device can engage the load to be raised (100 fig 7), which may be the chassis member of a static caravan that is to be levelled. Reel 30 may have a deployment arm 34 and may rotate about a horizontal axis 31 and may be pivotably mounted on the frame 18 about a vertical axis 33. Rotation of the body (82 fig 7) may be inhibited or limited to a range of 7-13 degrees by rubber abutment heads (92 fig 7) and the body (82 fig 7) may be provided with a concave surface (88 fig 7) and projecting fingers (87 fig 5) for engaging the load to be raised (100 fig 7).

Description

Improvements in or Relating to a Jack Apparatus and a Drive Apparatus Therefor

Technical Field

The invention relates to improvements in or relating to a jack apparatus and a drive apparatus therefor.

Background

Large objects such as static caravans are required to be moved and positioned so that they are level. Typically such static caravans have a chassis on which a cabin is mounted. The chassis has an axle with a pair of wheels so that the static caravan can be towed and moved when required. During positioning of the static caravan it is necessary to lift the chassis and secure it is place relative to the ground with supports so that it is level. Chocks may also be placed against the wheels to inhibit the static caravan from moving. The supports may be parts of the chassis that pivot to make contact with the ground or they may be wooden blocks. Such supports are required to be removed before the static caravan is moved to a different location.

It is known to use a bottle jack or a trolley jack to lift the chassis so that the supports can be fitted or removed. A person using the jack is typically required to crawl under the static caravan to position a lifting surface of the jack on a member of the chassis. A lever of the jack is then repeatedly pumped to raise the lifting surface to lift the chassis.

The supports are then located in position between the chassis and the ground. This process may need to be repeated until the chassis is level. During the process of lifting and fitting or removing the supports the person is typically required to repeatedly crawl under the chassis, which may be dangerous. Tn the case of using a trolley jack with a radial lifting arm the static caravan may lean as it is lifted which causes a horizontal force to act on the trolley jack, which is undesirable.

Overall, the known way of jacking a static caravan may be dangerous because the jack or the supports might fail or slip. The requirement for the person operating the jack to crawl underneath the chassis is undesirable. In addition, accessing the chassis member for placement of the lifting surface, and pumping the lever of the jack underneath the chassis to raise the lifting surface is awkward for the person operating the jack. Tn general the known way of lifting a static caravan is cumbersome and time consuming.

It is broadly an object of the present invention to address one or more of the above mentioned disadvantages of the previously known ways of lifting large objects such as static caravans.

Summary

What is required is a way of readily permitting an object, such as a static caravan, to be lifted, which may reduce or minimise at least some of the above-mentioned problems.

According to a first aspect of the invention, there provided a jack apparatus comprising a jack and a drive apparatus for providing a fluid under pressure to the jack via a hose for operation thereof, the drive apparatus comprising a body and a hose deployment device for deployment and retraction of the hose from the body.

Such a jack apparatus provides the advantage that a person can operate the jack using the drive apparatus which can be located adjacent to the object to be lifted. Accordingly, the requirement for the person to pump a lever of the jack according to the prior art whilst it is underneath the object is avoided. With the invention the hose deployment device provides the advantage that the jack can be moved independently of the drive apparatus and the hose is less likely to interfere with obstacles which may hinder operation of the jack apparatus. Due to the improved usability of the jack apparatus the time to lift and fit supports to level an object such as a static caravan may be significantly reduced.

Preferably the hose deployment device is configured for deployment and retraction of the hose from an upper region of the body. In a preferred embodiment the hose deployment device has an arm for deployment and retraction of the hose from an upper region of the body. Such an arrangement further provides the advantage that the hose is less likely to become snagged or caught on obstacles such as rocks, or other item on the ground.

Preferably the hose deployment device is a hose reel. Preferably the hose reel is rotatable relative to the body about a rotation axis for deployment and retraction of the hose from the hose reel. Preferably the rotation axis is substantially horizontal.

Preferably the hose reel is pivotably mounted to the body about a pivot axis. Preferably said pivot axis is substantially vertical.

The provision of the rotation axis being substantially horizontal and the pivot axis being substantially vertical is an advantageous arrangement because it allows the hose to be freely retracted and deployed which further assists the user when positioning the jack.

Preferably the hose deployment device is provided at one end of the body. This has the advantage that the drive apparatus can be moved adjacent to the object to be lifted so that the hose deployment device is closest to the object which further assists with deployment and retraction of the hose.

Preferably the jack has an attachment device with a bearing surface for engagement with an object to be jacked, the attachment device comprising a support which is attachable to a lifting member of the jack, the support being pivotable relative to the lifting member of the jack. Such an attachment device may provide the advantage of inhibiting leaning of the object when it is lifted.

Preferably said pivotable operation of the support relative to the lifting member of the jack is provided by a load member of the support, the load member for abutment with the lifting member of the jack.

Preferably the support comprises a recess for location over the lifting member of the jack. Such a recess is a convenient way of securing the attachment member to the lifting member of the jack.

Preferably the support comprises at least one guide member for constraining said pivotable operation of the support relative to the load member substantially in a single plane.

Preferably the support comprises at least one abutment part for inhibiting said pivotable operation of the support relative to the load member beyond a predetermined angle.

Preferably the predetermined angle is between 7 -13°. In a preferred embodiment the predetermined angle is substantially 10°.

Preferably the attachment device has at least one finger which protrudes from the bearing surface. Such a finger is useful because it inhibits the object to be jacked from slipping from the bearing surface.

According to a second aspect of the invention there is provided a drive apparatus for providing a fluid under pressure to a tool, the drive apparatus comprising a body and a hose deployment device for deployment and retraction of the hose from the body to provide the fluid to the tool for operation thereof.

Such a drive apparatus provides the advantage that the person can operate the tool using the drive apparatus which can be located adjacent to the object to be lifted. With the invention the hose deployment device provides the advantage that the tool, such as a jack, can be moved independently of the drive apparatus and the hose is less likely to interfere with obstacles which may hinder operation of the tool.

Preferably the hose deployment device is configured for deployment and retraction of the hose from an upper region of the body. Tn a preferred embodiment the hose deployment device has an arm for deployment and retraction of the hose from an upper region of the body. Such an arrangement further provides the advantage that the hose is less likely to become snagged or caught on obstacles such as rocks, or other item on the ground.

Preferably the hose reel is pivotably mounted relative to the body about a pivot axis.

Preferably said pivot axis is substantially vertical.

The provision of the rotation axis being substantially horizontal and the pivot axis being substantially vertical is an advantageous arrangement because it allows the hose to be freely retracted and deployed which further assists the user when operating the tool.

Preferably the hose deployment device is provided at one end of the body. This has the advantage that the drive apparatus can be moved adjacent to any work area where the tool is being used so that the hose deployment device is closest to the work area which further assists with deployment and retraction of the hose.

According to a third aspect of the invention there is provided an attachment device for a jack having a bearing surface for engagement with an object to be jacked, the attachment device comprising a support which is attachable to a lifting member of the jack, the support being pivotable relative to the lifting member of the jack.

Such an attachment device may provide the advantage of inhibiting leaning of an object when it is lifted using a jack. Such an arrangement may assist with stabilising the object when it is lifted and may reduce the possibility of the jack collapsing when the object is lifted.

Preferably the predetermined angle is between 7 -13°. In a preferred embodiment the predetermined angle is substantially 100.

Preferably the attachment device further includes at least one finger protruding from the bearing surface. Such a finger is useful because it inhibits the object to be jacked from slipping from the bearing surface.

Brief Description of the Drawings

Other features of the invention will be apparent from the following description of preferred embodiments shown by way of example only with reference to the accompanying drawings, in which; Figure 1 shows a perspective view of a jack apparatus according to an embodiment of the invention; Figure 2 shows a perspective view of a rear side of a drive apparatus of the jacking apparatus shown in Figure 1; Figure 3 shows a mounting arrangement for a hose reel shown in Figures 1 and 2; Figure 4 shows a perspective view of an air jack shown in Figure 1; Figure 5 shows a perspective view from above of an attachment for the air jack shown in Figures 1 and 4; Figure 6 shows a perspective view from below of the attachment shown in Figure 5; Figure 7 shows a partial cross section of the attachment shown in Figures 5 and 6; and Figure 8 shows a perspective view of the attachment shown in Figures 5 -7 in situ on the air jack shown in Figure 4.

Detailed Description

Figure 1 shows a perspective view of a jack apparatus according to an embodiment of the invention, generally designated 10. The jacking apparatus 10 comprises a drive apparatus 12 and a separate air jack 14. The jack 14 is a tool and it will be understood that the drive apparatus 12 may be used with any tool that requires a pressurised fluid supply for operation thereof The drive apparatus 12 is a compressor apparatus which comprises a frame 18, or body, mounted on four wheels 16. The frame 18 has an engine mounted to it at an upper region thereof The engine 20 is operable to drive an air compressor 22 which is also mounted to the frame 18 at an upper region thereof The air compressor 22 pumps air into a pressure vessel 24 which is mounted to the frame 18 at a lower region thereof The engine 20 and the compressor 22 are shown to be mounted above the pressure vessel 24 in the frame. The frame 18 substantially comprises a cage around the engine 20, the compressor 22 and the pressure vessel 24.

One end of the frame 18 forms a handle 26 so that the drive apparatus 12 can be gripped by a user and moved as required on the wheels 16. Another end of the frame 18 forms a platform 28 on which a hose reel 30 is attached with a pivotable mounting 32 which pivots about a vertical axis 33. The hose reel 30 is rotatable about a horizontal axis 31 and has a hose deployment arm 34 to feed an air supply hose 36 on and off the hose reel as required by the user when operating the air jack 14. The hose 36 may alternatively be termed a pipe or a duct. II will be appreciated that the hose reel 30 is rotatable about the axis 31 which is horizontal, whereas the pivotable mounting 32 permits the hose reel to pivot about the axis 33 which is vertical. The air supply hose 36 connects the pressure vessel 24 to the air jack 14 for supplying air under pressure to the air jack 14 to operate it. The air jack 14 is a known item which has a load platform 38 which can be raised or lowered by operating the air jack 14. The air jack 14 may also be known as a trolley jack whereby the load platform 38 can be raised or lowered substantially in the vertical direction.

Figure 2 shows a perspective view of a rear side of the drive apparatus 12 of the jacking apparatus 10 shown in Figure 1. In Figure 2 like features to the arrangements of Figure 1 are shown with like reference numerals. In Figure 2 the compressor 22 is shown to be connected to the pressure vessel 24 with an air hose 40. The pressure vessel 24 is connected an air filter 42 via an air hose 44. The air filter 42 is coupled to an oiler device 46 to provide lubrication in the air supply. The oiler device 46 is connected to a rotary connector 48 of the hose reel 30 via an air hose 50. The rotary connector 48 is located at a central part of the hose reel 30 and is connected to the air supply hose 36 which is shown to be wound onto the hose reel 30. When the air supply hose 36 is pulled by the user the hose reel 30 and rotary connector 48 allows the air supply hose 36 to be drawn off the hose reel 30 as it rotates without becoming twisted or kinking. The air supply hose 36 may be wound back onto the hose reel 30 as required. It will be appreciated that the hose deployment arm 34 assists with guiding the air supply hose 36 on and off the hose reel 30.

Figure 3 shows a perspective view of a mounting arrangement for the hose reel 30 shown in Figures 1 and 2, generally designated 60. n Figure 3 like features to the arrangements of Figure 1 are shown with like reference numerals. In Figure 3 the pivotable mounting 32 has a mounting support 62 which is secured to the platform 28 of the frame 18 with bolts 64. The mounting support 62 is pivotably attached to a mounting base 66 with a bolt (not shown). The mounting base 66 is attached to a connector arm 68 with bolts 70. The hose reel 30 is rotatably mounted to the connector arm 68 with a bolt (not shown). In Figure 3 the air supply hose 36 is shown to be loaded onto the hose reel 30.

Figure 4 shows a perspective view of the air jack 14 shown in Figure 1, generally designated 14. In Figure 4 like features to the arrangements of Figure 1 are shown with like reference numerals. In Figure 4 the load platform 38 is shown which has a blind hole in it for location of a spigot 72 of one of three spacer parts 74. The load platform 38 and the spacer parts 74 may be termed lifting members of the air jack 14. The three spacer parts 74 may have different diameters.

Figure 5 shows a perspective view from above of an attachment for the air jack 14 shown in Figures 1 and 4, generally designate 80. n Figure 5 like features to the arrangements of Figure 1 and 4 are shown with like reference numerals. In Figure 5 the spacer part 74 is shown to rest on the load platform 38 whereby the spigot 72 (not shown) of the spacer part 74 is located in the blind hole (not shown) of the load platform 38. The attachment 80 comprises a body 82 which is substantially the shape of an open box. The body 82 may also be known as a support. The open side of the box is shown to be located over the spacer part 74. The body 82 may be considered to comprise a recess for location over the spacer part 74. The body 82 has a load member 84 which is tubular in shape. The load member 84 is welded at either end within the body 82, so that the load member 84 rests on the spacer part 74 when the body 82 is located over it. In an alternative arrangement the load member 84 is rotatably mounted at either end within the body 82, for example with bearings. It will be appreciated that a curved surface of the load member 84 rests on the spacer part 74 so that the body 82 can pivot relative to the spacer part 74 about the pivot axis of the load member 84. The body 82 has a bearing surface 86 at an upper part thereof which has a concave surface shown at 88, which may be a spherical or conical surface. The bearing surface 86 is for abutment with an object to be lifted by the air jack 14 such as a static caravan. Four fingers 87 protrude above the bearing surface 86 at a respective corner thereof for engagement with an object to be lifted such as a chassis member of static caravan. In use the fingers 87 and the concave surface 88 inhibit the object from slipping from the bearing surface 86 when the object is lifted. It will be appreciated that only one finger 87 or a part of the body 82 that protrudes from the bearing surface may be required to inhibit the object from slipping.

Figure 6 shows a perspective view from below of the attachment shown in Figure 5, generally designate 80. In Figure 6 like features to the arrangements of Figure 5 are shown with like reference numerals. In Figure 6 the spigot 72 of the spacer part 74 is shown to be located in the hole of the load platform 38. Also shown are guide members on first opposing inside surfaces of the body 82. The guide members 90 abut sides of the spacer part 74 so that the body 82 is constrained to pivot relative to the spacer part 74 about the axis of the load member 84. Such constraining inhibits movement of the spacer part 74 along to the load member 84 so that the body 82 pivots substantially in a single plane. The guide members 90 may be made from an impact resistant plastics material such as Nylon. The body 82 and the load member 84 are of steel. Also shown are abutment heads 92 on second opposing inside surfaces of the body 82. The abutment heads 92 abut sides of the spacer part 74 to inhibit contact with the body 82. The abutment heads 92 may be made from a resilient material such as rubber. The abutment heads 92 are substantially mushroom shaped with the stalk of the mushroom shape passing through the sides of the body 82 so that the abutment heads 92 are attached to the body 82.

Figure 7 shows a partial cross section of the attachment shown in Figures 5 and 6, generally designate 80. In Figure 7 like features to the arrangements of Figure 5 and 6 are shown with like reference numerals. In Figure 7 the load member 84 is shown to have a pivot axis 94 so that the body 82 is able to pivot up to about 100 from a horizontal axis 96. The horizontal axis 96 is shown to be at a right angle to a vertical axis 98 of the spacer part 74. It can be seen that the part of the spacer part 74 which makes contact with the load member 84 is curved so that the load member 84 sits more securely on the spacer part 74.

Also shown is a chassis member 100 of a static caravan. It will be appreciated that as the air jack 14 is operated the attachment 80 moves vertically upwards so that a top edge 102 of the body 82 makes contact with an underside of the chassis member 100. As the attachment 80 continues to move upwards it rotates due to contact of the top edge 102 with the chassis member 100 until the bearing surface 86 is in full contact with the chassis member 100. Tf the chassis member 100 is not horizontal, such as slightly away from horizontal, the attachment 80 will rotate until it has the same orientation as the chassis member 100, which is advantageous for lifting the chassis member 100.

Figure 8 shows a perspective view of the attachment shown in Figures 5 -7 in situ on the air jack shown in Figure 4. In Figure 8 like features to the arrangements of Figure 1 -7 are shown with like reference numerals. In Figure 8 the load member 84 of the body 82 is shown to rest on the spacer part 74. The spigot 72 of the spacer part 74 locates in the load platform 38 so that the spacer part 74 rests on it. It will be appreciated that the spacer part 74 is rotatable relative to the load platform 38 so that the attachment 80 can be aligned with the item to be lifted. In the case of lifting a chassis member 100, the attachment 80 can be rotated so that the fingers 87 are either side of it.

When the jack apparatus 10 is in use, the drive apparatus 12 and the air jack 14 are moved near to the object to be lifted, such as a static caravan. A suitable spacer part 74 is selected and the spigot 72 of the spacer part 74 is located into the blind hole in the load platform 38. The attachment 80 is then located over the spacer part 74. The engine 20 is then started which drives the air compressor 22 so that the pressure vessel 24 is charged with compressed air. The user then places the air jack 14 under the object to be lifted, such as a chassis member of a static caravan, so that the attachment 80 is underneath a part of the chassis. The user then operates the air jack 14 to raise the load platform 38 so that the bearing surface 86 of the attachment 80 makes contact with the chassis member and lifts it. The user may then fit supports, such as blocks of wood, to secure the chassis in position relative to the ground. Typically the jack apparatus 10 is capable of lifting about 22 Tons or more.

It will be appreciated that the air supply hose 36 provided on a hose reel 30 allows the air supply hose 36 to be deployed and retracted from the drive apparatus 12 as required.

Such an arrangement is advantageous because it allows the user to concentrate on positioning the air jack 14 underneath the object to be lifted without diverting attention to consider where the air supply hose 36 is located. The provision of the hose deployment arm 34 at an upper region of the drive apparatus 12 means that the air supply hose 36 is less likely to become snagged or caught on obstacles such as rocks, or other item on the ground. The hose deployment arm 34 is operable to deploy the air supply hose 34 from the drive apparatus 12 at a height of about 1.0 -1.5m above ground level which is sufficient to clear most obstacles that may typically be encountered. Furthermore the provision of the hose reel 30 being pivotably mounted to the drive apparatus 12 means that the air supply hose 36 can be freely retracted and deployed which further assists with positioning the air jack 14 underneath the chassis.

The attachment 80 for the air jack 14 may pivot about the axis 94 of the load member 84 which may inhibit leaning of the object when it is lifted. Such an arrangement may assist with stabilising the object when it is lifted and may reduce the possibility of the air jack 14 collapsing when the object is lifted. The attachment 80 may assist with vertically alignment of forces to inhibit the object or the air jack 14 from leaning during lifting.

n the above described embodiments the drive apparatus 12 and the air jack 14 are provided on wheels so that they are portable. In one embodiment the drive apparatus 12 and the air jack 14 are provided on a trailer that can be moved into position by a car or tractor. This is an advantageous arrangement because the drive apparatus 12 and the air jack 14 are relatively heavy items for a user to move.

In the above described embodiments the compressor 22 and the engine 20 are shown to provide the required air under pressure to operate the air jack 14. It will be appreciated that any general fluid pump device or drive apparatus may be used for this purpose to provide any fluid under pressure to operate the jack such as a liquid or gas. In the case of a liquid, a hydraulic jack must be used instead of the air jack 14. In one arrangement the air jack 14 may be an inflatable bag such as a bellow device for lifting of moving items, and the drive apparatus 12 may be used to operate the inflatable bag.

Claims

CLAIMS1. A jack apparatus comprising a jack and a drive apparatus for providing a fluid under pressure to the jack via a hose for operation thereof, the drive apparatus comprising a body and a hose deployment device for deployment and retraction of the hose from the body.
2. A jack apparatus according to claim 1, wherein the hose deployment device is configured for deployment and retraction of the hose from an upper region of the body.
3. A jack apparatus according to claim 2, wherein the hose deployment device has an arm for deployment and retraction of the hose from an upper region of the body.
4. A jack apparatus according to claim 1, 2 or 3, wherein the hose deployment device is a hose reel.
5. A jack apparatus according to claim 4, wherein the hose reel is rotatable relative to the body about a rotation axis for deployment and retraction of the hose from the hose reel.
6. A jack apparatus according to claim 5, wherein the rotation axis is substantially horizontal.
7. A jack apparatus according to claim 4, 5 or 6, wherein the hose reel is pivotably mounted to the body about a pivot axis.
8. A jack apparatus according to claim 7, wherein said pivot axis is substantially vertical.
9. A jack apparatus according to any preceding claim, wherein the hose deployment device is provided at one end of the body.
10. A jack apparatus according to any preceding claim, wherein the jack has an attachment device with a bearing surface for engagement with an object to be jacked, the attachment device comprising a support which is attachable to a lifting member of the jack, the support being pivotable relative to the lifting member of the jack.
11. A jack apparatus according to claim 10, wherein said pivotable operation of the support relative to the lifting member of the jack is provided by a load member of the support, the load member for abutment with the lifting member of the jack.
12. A jack apparatus according to claim 10 or 11, wherein the support comprises a recess for location over the lifting member of the jack.
13. Ajack apparatus according to claim 10, 11 or 12, wherein the support comprises at least one guide member for constraining said pivotable operation of the support relative to the load member substantially in a single plane.
14. A jack apparatus according to any of claims 10 -13, wherein the support comprises at least one abutment part for inhibiting said pivotable operation of the support relative to the load member beyond a predetermined angle.
15. A jack apparatus according to claim 14, wherein the predetermined angle is between 7 -13°.
16. A jack apparatus according to claim 15, wherein the predetermined angle is substantially 10°.
17. A jack apparatus according to any of claims 10 -16, wherein the attachment device has at least one finger which protrudes from the bearing surface.
18. A jack apparatus according to any preceding claim as substantially described herein with reference to the accompanying drawings.
19. A drive apparatus for providing a fluid under pressure to a tool, the drive apparatus comprising a body and a hose deployment device for deployment and retraction of the hose from the body to provide the fluid to the tool for operation thereof
20. A drive apparatus according to claim 19, wherein the hose deployment device is configured for deployment and retraction of the hose from an upper region of the body.
21. A drive apparatus according to claim 20, wherein the hose deployment device has an arm for deployment and retraction of the hose from an upper region of the body.
22. A drive apparatus according to claim 19, 20 or 21, wherein the hose deployment device is a hose reel.
23. A drive apparatus according to claim 22, wherein the hose reel is rotatable relative to the body about a rotation axis for deployment and retraction of the hose from the hose reel.
24. A drive apparatus according to claim 23, wherein the rotation axis is substantially horizontal.
25. A drive apparatus according to claim 22, 23 or 24, wherein the hose reel is pivotably mounted relative to the body about a pivot axis.
26. A drive apparatus according to claim 25, wherein said pivot axis is substantially vertical.
27. A drive apparatus according to any of claim 19 -26, wherein the hose deployment device is provided at one end of the body.
28. A drive apparatus as substantially described herein with reference to Figures 1 - 3 of the accompanying drawings.
29. An attachment device for a jack having a bearing surface for engagement with an object to be jacked, the attachment device comprising a support which is attachable to a lifting member of the jack, the support being pivotable relative to the lifting member of the jack.
30. An attachment device according to claim 29, wherein said pivotable operation of the support relative to the lifting member of the jack is provided by a load member of the support, the load member for abutment with the lifting member of the jack.
31. An attachment device according to claim 29 or 30, wherein the support comprises a recess for location over the lifting member of the jack.
32. An attachment device according to claim 29, 30 or 31, wherein the support comprises at least one guide member for constraining said pivotable operation of the support relative to the load member substantially in a single plane.
33. An attachment device according to any of claims 29 -32, wherein the support comprises at least one abutment part for inhibiting said pivotable operation of the support relative to the load member beyond a predetermined angle.
34. An attachment device according to claim 33, wherein the predetermined angle is between 7 -13°.
35. An attachment device according to claim 34, wherein the predetermined angle is substantially 100.
36. An attachment device according to any of claims 29 -35, and further including at least one finger protruding from the bearing surface.
37. An attachment device as substantially described herein with reference to Figures 5-7 of the accompanying drawings.