AU2014100861A4 - Jack - Google Patents

Abstract

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 A jack with a main body, a telescopic member that advances out of the body and a locking assembly that selectively locks the member against movement back into the body.

Description

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 JACK FIELD OF THE INVENTION [0001] The present invention relates to a jack particularly, but not exclusively for use in the mining industry. BACKGROUND OF THE INVENTION [0002] A hydraulic jack is commonly used in the mining industry to lift and support a mining vehicle during a maintenance or repair operation. Four jacks are placed at jacking points under the vehicle and engaged to lift the vehicle. It is not considered safe for personnel to work under the vehicle while jacked as hydraulic pressure to the jacks may fail. As such, additional support stands need to be manoeuvred into place beneath the vehicle before any personnel are allowed beneath the vehicle. OBJECT OF THE INVENTION [0003] The present invention seeks to provide an alternative form of jack. SUMMARY OF THE INVENTION [0004] In accordance with the present invention there is provided a jack with a main body, a telescopic member that advances out of the body and a locking assembly that selectively locks the member against movement back into the body. [0005] Preferably, the locking assembly includes a rack and an associated pawl.

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -2 [0006] Preferably, the rack is formed by a series of teeth on the telescopic member. [0007] Preferably, the pawl is biased into engagement with the rack by a locking lever. [0008] Preferably, the lever acts as a counterweight on the pawl. [0009] Preferably, the lever is moveable from an engaged to a release position, where the pawl is free to move away from the member, to enable the member to retract into the main body. [0010] Preferably, the lever and pawl are on a common pivot pin which is mounted on one side of the body, adjacent the member. [0011] Preferably, the jack includes an isolation lock to secure the lever in the engaged position. [0012] Preferably, the lock includes a fixture in the lever that allows the lever to be secured relative to the body. [0013] Preferably, the fixture includes an aperture for receipt of a padlock or the like. [0014] Preferably, the jack includes a second lever and pawl on an opposite side of the body to lock with a rack on an opposite side of the member. [0015] Preferably, the levers are adapted to be locked together by connecting the associated fixture of each lever. [0016] Preferably, the main body includes a housing that accommodates a ram to lift and lower the telescopic member. [0017] Preferably, the housing is adapted to fit different dimension rams for varying the H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -3 lift capacity of the jack. [0018] Preferably, the telescopic member includes a lifting head on a column and an underside of the head has a fitting to fix the head to the ram. [0019] Preferably, the jack has a base with apertures to receive fasteners that fix a lower end of the ram. [0020] Preferably, a side wall of the housing has a port to receive a tube that carries pressurised fluid to power the column. [0021] Preferably, the jack includes hoist points. Preferably, the hoist points are provided by sleeves attached to the jack housing to receive tines of a forklift or the like. BRIEF DESCRIPTION OF THE DRAWINGS [0022] The invention is described in more detail, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a jack, in a lowered position; Figure 2 is a perspective view of the jack in a first locking position; Figure 3 is a perspective view of the jack in a last locking position; Figure 4 is a partial sectional view of the jack of Figure 3; Figure 5 is a cross-sectional view of the jack of Figure 4; Figure 6 is a diagrammatic cross-sectional view of the jack; H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -4 Figure 7 is an image of another example of a jack; Figure 8 is an image of the jack in a lowered position; Figure 9 illustrates the jack with an isolation lock and an adapter; and Figure 10 shows the jack with the adapter fitted onto a lifting head of the jack. DETAILED DESCRIPTION OF THE INVENTION [0023] Referring to Figure 1, a jack 1 is shown in a lowered position. The jack 1 has a main body 2 with a base plate 3, front and back walls 4, 5 and opposite sides 6, 7, and a telescopic member 8 that fits inside the body 2. [0024] The telescopic member 8 includes a lifting head 9 coupled to a column 10 that drives the member 8 in and out of an opening 11 in a top 12 of the body 2. The lifting head 9 is in the form of a cylindrical spigot 13 with a central fastener 14. [0025] The jack 1 also includes a pawl 15 formed of an elongate bar 16 that extends along the opening 11, across one side 6 of the jack 1. The bar 16 has two knuckle portions 17 that pivotally mount the pawl 15 onto a hinge pin 18. A second pawl 19 is positioned along the opposite side 7 of the jack 1. [0026] Locking levers 20, 21 are also mounted onto the respective hinge pin 18. Each locking lever 20, 21 acts as a counterweight on the pawls 15, 19. The locking lever 21 is shown in an engaged position, which biases the pawl 19 toward the telescopic member 8. [0027] The other locking lever 20 is shown in a release position, which removes the counterweight bias from the pawl 15 so that the pawl 15 is free to rotate away from the member 8.

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -5 [0028] The jack 1 also has lifting points 22 in the form of sleeves 23 that can be used to lift and manoeuvre the jack 1 using tines of a forklift of the like (not shown). [0029] Referring now to Figure 2, the jack 1 is shown in a first locking position, where the column 10 has advanced out of the opening 11 and is secured against reverse movement back into the body 2 by a locking assembly 24, which includes parallel racks of teeth 25 on the column 10 that engage with the pawl 15. Identical racks of teeth 26 are provided on the opposite side 27 of the column 10, to engage with the other pawl 19. [0030] As the column 10 moves out through the opening 11, the pawls 15, 19 ride over the inclined front surface 28 of the teeth 25, 26 and are pushed outwardly to allow the column 10 to advance out of the body 2. Once the teeth 25, 26 have passed the respective pawls 15, 19, the locking assembly 24 is again engaged by the pawls 15, 19 being forced into a groove 29 beneath the teeth 25, 26, under bias of the respective locking lever 20, 21. [0031] With regard to Figure 3, the column 10 is shown in a last locking/top position, where the pawls 15, 19 are engaged in a groove 29 associated with a lower part of the racks of teeth 25, 26. [0032] As may be appreciated, when the locking assembly 24 is engaged, the telescopic member 8 is able to be advanced out of the body 2 but is prevented from retracting into the body 2. [0033] Referring now to Figures 4 and 5, the jack 1 is shown in partial cross-section and a ram 30 (shown in phantom lines) is mounted internally of the jack 1, inside a housing 31 formed by the main body 2 and an internal cavity of the column 10. The ram 30 includes an outer cylinder 32 that is secured at a bottom end 33 to the main body 2 by suitable connectors 34 that are fixed in anchor points 35 in the base plate 3. [0034] The cylinder 32 also includes a coupling 36 that connects to a tube 37 that passes through a port 38 in a side 6 of the jack 1, for delivery of working fluid to the ram 30.

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -6 [0035] The ram 30 has a piston 39 that is driven in and out of the cylinder 32, under action of the working fluid, in order to move the column 10 in and out of the main body 2. A top end 40 of the piston 39 is connected into a fitting 41 provided in the column 10, at an underside 42 of the lifting head 9, that provides another anchor point 43 that allows the piston 39 to be secured in place by the fastener 14. As such, the ram 30 is fixed into the housing 31 at anchor points 35, 43 that secure both the top and bottom ends 40, 33 of the ram 30. [0036] The housing 31 has internal dimensions sufficient to receive a maximum capacity ram, capable of lifting, say 250 tonne. However, the housing 31 also allows for different capacity rams to be swapped in an out, as required. For example, a smaller dimensioned 50 tonne ram 44 may be installed in the housing 31, and be connected at the anchor points 35, 43 to secure the top and bottom ends of the ram, 40, 33 as shown in Figure 6. Alternatively, smaller dimension rams can be used, such as a 20 tonne ram or a 10 tonne ram, diagrammatically illustrated by reference numbers 45, 46, respectively. [0037] Turning now to Figure 7, the levers 20, 21 are shown, in another example of the jack 1, with an isolation lock 47 in the form of a fixture 48 attached to each lever 20, 21 with apertures 49 that are aligned to enable the levers 20, 21 to be locked together when the levers 20, 21 are in the engaged position, to bias the pawls 15, 19 against the column 10. [0038] If the isolation lock 47 is not in use, the levers 20, 21 can be freely rotated into an release position, which removes the bias from the pawls 15, 19. This allows the pawls 15, 19 to freely rotate away from the column 10 and fall into a lowered position when the racks of teeth 25, 26 of the column 10 push the pawls 15, 19 outwardly during the next advance of the column 10, which releases the lock assembly 24 and frees the column 10 to return to retract back into a lowered position, as shown in Figure 8, inside the main body 2 of the jack 1.

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -7 [0039] As such, the jack 1 has dual safety locks, in the form of the locking levers 20, 21 and the isolation lock 47, that can be engaged to allow the column 10 to advance out of the body 2 but not retract, until both sets of safety locks are released. [0040] Figure 9 shows a padlock 50 that may be used to secure the isolation lock 47 against release. Any other form of suitable lock can, of course, be used. [0041] Figure 9 also shows a prototype of an adapter 51 that has a socket end 52 designed to fit over the spigot 13 of the lifting head 9 and be supported on a shoulder 53 of the column 10. The adapter 51 extends the effective length of the column 10, as illustrated in Figure 10, and can be used in circumstances where the column 10 does not have a sufficient stroke length to reach and support an object that needs to be jacked. In the case of mining, for example, many mining vehicles are at different heights. As such, the jack 1 can be designed so that the column 10 will support lower vehicles, without the adapter 51, and can be used to support higher vehicles, with elevated jack points, with the adapter 51 fitted to the column 10. [0042] The adapter 51 may also have a specifically profiled head, as required, to fit with custom designed jack points on the vehicles. [0043] As may be appreciated from the above, the jack 1 is universal in that a single main body 2 and column 10 can be used to lift loads, across a range of lift capacity scenarios, just by swapping in an appropriate capacity ram 30. The jack 1 can also be used to provide lift across a range of different heights through use of an appropriate length adapter 51, as required. [0044] Since the jack 1 has dual safety locks 24, 47 that prevent the column 10 dropping back into the main body 2, the jack 1 is suitable for lifting mining vehicles and the like for immediate access of personnel under the vehicles, instead of requiring the use of separate support stands under the vehicles, as used in the prior art.

H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 LIST OF PARTS 1. Jack 2. Main body 3. Base plate 4. Front wall 5. Back wall 6. Side 7. Side 8. Telescopic member 9. Lifting head 10. Column 11. Opening 12. Top 13. Spigot 14. Fastener 15. Pawl 16. Bar 17. Knuckle portions 18. Hinge pin 19. Pawl 20. Locking lever 21. Locking lever 22. Lifting point 23. Sleeve 24. Locking assembly 25. Rack of teeth 26. Rack of teeth 27. Side 28. Inclined surface 29. Groove H:\cab\Interwoven\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 -9 30. Ram 31. Housing 32. Outer cylinder 33. Bottom end 34. Connector 35. Anchor point 36. Coupling 37. Tube 38. Port 39. Piston 40. Top end 41. Fitting 42. Underside 43. Anchor point 44. Ram 45. Ram 46. Ram 47. Isolation lock 48. Fixture 49. Aperture 50. Padlock 51. Adapter 52. Socket end 53. Shoulder

Claims (19)

1. A jack with a main body, a telescopic member that advances out of the body and a locking assembly that selectively locks the member against movement back into the body.

2. The jack of claim 1, wherein the locking assembly includes a rack and an associated pawl.

3. The jack of claim 2, wherein the rack is formed by a series of teeth on a column of the telescopic member.

4. The jack of claim 3, wherein the pawl is biased into engagement with the rack by a locking lever.

5. The jack of claim 4, wherein the lever acts as a counterweight on the pawl.

6. The jack of claim 5, wherein the lever is moveable from an engaged to a release position, where the pawl is free to move away from the member, to enable the member to retract into the main body.

7. The jack of claim 6, wherein the lever and pawl are on a common pivot pin which is mounted on one side of the body, adjacent the member.

8. The jack of claim 4, wherein the jack includes an isolation lock to secure the lever in the engaged position.

9. The jack of claim 8, wherein the isolation lock includes a fixture in the lever that allows the lever to be secured relative to the body.

10. The jack of claim 9, wherein the fixture includes an aperture for receipt of a padlock or the like. H:\cab\Intrwovn\NRPortbl\DCC\CAB\6244328_I.DOC-23/04/2014 - 11

11. The jack of claim 10, further including a second lever and pawl on an opposite side of the body to lock with a rack on an opposite side of the member.

12. The jack of claim 11, wherein the levers are adapted to be locked together by connecting the associated fixture of each lever.

13. The jack of claim 1, wherein the main body forms part of a housing that accommodates a ram to lift and lower the telescopic member.

14. The jack of claim 13, wherein the housing is adapted to fit different dimension rams to vary the lift capacity of the jack.

15. The jack of claim 14, wherein the telescopic member includes a lifting head and an underside of the head has a fitting to fix the head to the ram.

16. The jack of claim 15, wherein the jack has a base with apertures to receive connectors that fix a lower end of the ram.

17. The jack of claim 1, wherein a side wall of the housing has a port to receive a tube that carries pressurised fluid to power the ram.

18. The jack of claim 1, wherein the jack includes hoist points.

19. The jack of claim 18, wherein the hoist points are provided by sleeves attached to the jack housing to receive tines of a forklift or the like.