GB2416528A

GB2416528A - Door type lifting jack

Info

Publication number: GB2416528A
Application number: GB0416442A
Authority: GB
Inventors: Dominic Alan Farnworth
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-07-23
Filing date: 2004-07-23
Publication date: 2006-02-01
Also published as: EP1786717A1; CN101027241A; WO2006008480A1; GB0416442D0

Abstract

The present invention is a manually operated jacking device 10, the device comprising: a support 11; at least one elongate member 12 extending from the support in a longitudinal direction; an elongate driving member 13 arranged in use to move in the longitudinal direction relative to the elongate member; a contact member 15 constrained to move with the driving member and arranged in use to engage an object to be jacked; wherein a jacking mechanism 14 distal from the support is arranged, in a jacking condition, to move the driving member and the contact member in a jacking direction with the contact member moving relative to the support and, in a release condition, the driving member and contact member are able to move relative to the support. Preferably, the jacking mechanism 14 comprises one or more spring biased apertured plates mounted at an angle relative to the elongate member 12 and operated by a trigger 20. Preferably a release lock also being a spring biased apertured plate(s) is provided as is an adjustable retarder being two brake means. A stabilising support such as a roller or plastics member 16 can also be provided.

Description

1 241 6528 Manually Operated Jacking Device The present invention relates

to a manually operated jacking device and a method for operating the same.

It is known to provide a jacking device for jacking a load away from a substrate, wherein a pair of jaws are pivotal about one another. In use, the lower jaw rests upon the substrate such as the ground, whilst a load, such 0 as a door to be fitted upon hinges, is placed upon the upper jaw. The jaws are then opened so as to raise the door above the ground. Once the door reaches a satisfactory elevation, fitting upon the hinges is made easier.

However, in such prior art devices, since the

elevation is created by the pivotal movement of a pair of jaws, the object being lifted moves in an arcuate manner about the pivot point. Such arcuate movement is disadvantageous in applications involving the precise elevation of a load to a desired position.

In addition, such prior art lifting devices elevate the load from a lower region of the load and do not 2s provide any stability to an upper region of the load.

This is disadvantageous when lifting loads having a large substantially planar face such as a door or fence panel.

It is an aim of the present invention to provide a manually operated jacking device and method of jacking an object away from a substrate having a substantially linear jacking motion.

It is also an aim of the present invention to provide a manually operated jacking device and method of jacking an object away from a substrate which stabilises an object being jacked.

Additional aims of preferred embodiments of the present invention will also become apparent from the

description which follows.

lo According to the present invention there is provided an apparatus and method as set forth in the appended claims. Preferred features of the invention will be apparent from the dependent claims, and the description which follows.

According to a first aspect of the present invention, there is provided a manually operated jacking device, the device comprising: a support; at least one elongate member extending from the support in a longitudinal direction; an elongate driving member arranged in use to move in the longitudinal direction relative to the elongate member; a contact member constrained to move with the driving member and arranged in use to engage an object to be jacked; wherein a jacking mechanism distal from the support is arranged, in a jacking condition, to move the driving member and the contact member in a jacking direction with the contact member moving relative to the support and, in a release condition, the driving member and contact member are able to move relative to the support in a direction opposed to the jacking direction.

According to a second aspect of the present invention, there is provided a method of jacking an object, comprising the steps of: supporting a jack; engaging an object with a contact member of the jack; operating a jacking mechanism in a jacking condition so as to move a driving member and the contact member in a jacking direction relative to the support; operating the jacking mechanism in a release condition so as to allow the driving member and the contact member to move relative to the support in a direction opposed to the jacking direction.

According to a third aspect of the present invention, there is provided a method of operating a jack, suitable for use with the device described herein.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a side view of a first preferred embodiment of the present invention; Figure 2 is a front view of the first preferred embodiment of the present invention; Figure 3 is a side view of a jacking mechanism of the first preferred embodiment of the present invention; Figure 4 is a cross section along the line A-A through the jacking mechanism of the first preferred embodiment of the present invention; Figure 5 is a side view of the first preferred embodiment of the present invention arranged in use to lift a load; 5Figure 6 is a side view of a second preferred embodiment of the present invention; Figure 7 is a front view the second preferred embodiment of the present invention; Figure 8 is a side view of a jacking mechanism of the second preferred embodiment of the present invention; Figure 9 is a perspective view of the second preferred embodiment; Figure 10 is a side view of a base of an embodiment of the present invention having wheels; and Figure 11 is a side view of a preferred embodiment of a stabilising means.

As shown in Figure 1, a first preferred embodiment of the present invention 10 comprises a base 11, a support leg 12 which extends upward from the base 11, an elongate driving member 13 which is arranged in an axis parallel to the support leg 12. The driving member 13 is moveable by a jacking mechanism 14, in response to activation of a trigger 20 by a user. Activation of the trigger 20 causes the jacking mechanism 14 and driving member 13 affixed thereto, to move along the support leg 12.

When the present invention is arranged in a vertical orientation, operation of the trigger 20 causes the jacking mechanism 14 and driving member 13 to move away from the base 11 in a vertically upward direction.

Further, the jacking mechanism 14 is also operable to allow the jacking mechanism 14 and driving member 13 to be moved along the support leg 12 in a direction toward the base 11, opposed to the upward jacking direction.

lo The device further comprises a contact member 15, arranged at a lower region of the driving member 13, for in use making contact with an object to be jacked, and a stabiliser 16 for making contact with and stabilising an upper region of the object.

The base 11 is provided for supporting the jacking device against a surface such as the ground, or against an object providing a surface to jack against. In use, the device may be used to elevate an object upward from the ground or floor surface. However, preferred embodiments of the present invention may be used for, in particular, lifting planar objects such as internal and external doors, garage doors, radiators, plaster boards, and fence panels. It will further be understood that the usefulness of the present invention is not restricted to elevating objects upward. The present invention may also be used for jacking apart two objects in a horizontal direction and, in particular, for laying laminate type flooring materials.

In the first preferred embodiment, the support leg 12 is vertical which, when the present invention is arranged in a vertical orientation, extends upward from the base 11. The support leg 12 and base 11 provide a stable structure against which the jacking mechanism 14, driving member 13 and contact member 15 can be forceably driven upward.

In the first preferred embodiment of the present invention the jacking mechanism 14 is attached to an end of the driving member 13, although the jacking mechanism may be connected to any position of the driving member 13, lo with the contact arm 15 suitably positioned about the driving member 13 either above or below the jacking mechanism 14.

In the first preferred embodiment, the contact member 15 is a contact arm 15 having a horizontal base 15b, which may be arranged in use to engage with the underside of an object to be lifted (or against a side surface of an object being moved horizontally in a different orientation to that shown). In the first preferred embodiment, the contact arm 15 is provided at a lower end of the driving member 13 so that the jacking mechanism 14 moves the driving member 13 and contact arm 15 in either a jacking direction away from the base 11 or a release direction toward the base 11. Alternatively, the contact arm 15 may be arranged at a position of the driving member 13 above the jacking mechanism 14 so as to lift an object from a position above the jacking mechanism 14.

As can be seen from Figures 1 and 2, the support leg 12 of the preferred embodiment projects though an opening in the contact arm 15. A portion of the contact arm 15a may be made from a polymer material such as nylon.

Advantageously, the use of a polymer material acts as a bearing allowing the support leg 12 to pass through the contact arm with reduced friction.

The stabiliser 16 is provided for, in use, making contact at the side with an object being elevated or moved. The stabiliser 16 may be a polymer or rubber block which is arranged to make contact with and stabilise the object. Advantageously, this provides additional stability to the object over that provided by a lo conventional jacking device. The use of a polymer or rubber as the stabiliser 16 material reduces the risk of the object being marked or damaged by contact with the stabiliser 16. Alternatively, a roller may be arranged to roll in a direction transverse to the driving member 13 axis so as to roll against and stabilise an object being jacked.

Figure 3 shows an internal side view of a preferred embodiment of the jacking mechanism 14. The jacking mechanism 14 comprises the trigger 20, which is arranged to move between a first position and a second position about a pivot 21. The jacking mechanism 14 further comprises a handle 22. In the first position, the trigger is in a downward position distal from the handle 22, whilst in the second position the trigger 20 is in an upward position, having been pivoted toward the handle 22.

In the second position, the trigger 20 may abuts the handle 22.

A gripping plate 23 is arranged to be actuated by the trigger 20. The support leg 12 passes through an aperture 24 provided in the gripping plate 23, as shown in Figure 4. A spring 25 normally biases the gripping plate 23 to lie substantially perpendicular to the longitudinal axis defined by the axis of the support leg 12, whilst the trigger 20 rests in a first or downward position. When the trigger 20 is moved to the second or upward position, the gripping plate 23 becomes oriented to form an acute angle with respect to the longitudinal axis.

The operation of the jacking mechanism 14 will now be described with reference to Figures 3 and 4. As shown in lo Figure 3, in the preferred embodiment, the support leg 12 passes through the aperture 24 provided in the gripping plate 23. The aperture in the gripping plate 23 is slightly larger than the support leg 12. Although shown as rectangular, the aperture 24 may be any suitable shape for gripping the support leg 12. When the trigger 20 is in the first position, jacking mechanism 14 is free to move along the support leg 12. However, when the trigger 20 is moved toward the second position, the gripping plate 23 becomes acutely angled with respect to the longitudinal axis.

With that imposed angle, the top of one side and the bottom of the opposing side of the gripping plate 23 is brought into contact with the support leg 12. The opposing contacting sides of the gripping plate 23 then bite into or grip the opposing faces of the support leg 12. As movement of the trigger 20 continues toward the second or upward position adjacent to the handle 22, the jacking mechanism 14 and associated driving member 13 are forcibly driven upward. In addition, the contact arm 15 is also driven upward by movement of the driving member 13.

When the trigger 20 is moved to return from the second or upward position to the first position in a downward direction, the gripping plate 23 moves toward an axis perpendicular to the longitudinal axis and does not grip the support leg 12. Reciprocating motion of the trigger between the first and second positions causes the jacking mechanism, driving member 13 and contact arm 15 to be incrementally driven upward away from the base 11 in a jacking direction.

A preferred embodiment of the jacking mechanism 14 lo further comprises a locking catch 26, which moves about a pivot 27. The locking catch 26 is normally biased by a second spring 28 in an upward or locked position acutely angled with respect to the longitudinal direction.

Movement of a button 29 actuates the locking catch 26.

An aperture is provided in the locking catch 26 through which the support leg 12 passes. The locking catch 26 aperture is suitably larger than the support leg 12 so as to cause opposing faces of the aperture to bite into or grip the support leg 12 when the locking catch 26 is in a locked position, acutely angled with respect to the longitudinal axis. In the first preferred embodiment, the locking catch 26 is in the locked position when angled upwardly. The jacking mechanism 14, driving member 13 and 2s contact arm 15 are thus prevented from moving in a downward direction toward the base 11 when the locking catch 26 is in the locked position. The locking catch 26 causes the jacking mechanism 14, driving member 13 and contact arm 15 to be ratcheted upward upon repeated activation of the trigger 20. However, when the locking catch 26 is moved about its pivot 27 by a operation of the button 29, the locking catch moves toward a horizontal position toward an axis perpendicular to the longitudinal axis. In this position, the opposing faces of the aperture do not bite into or grip the support leg 12. In this release position, the jacking mechanism 14, driving member 13 and contact arm 15 are permitted to fall under s gravity or be forced down in a release direction toward the base 11.

Figure 5 shows the first embodiment of the present invention 10 arranged in use upon a floor 40 to lift an 0 object 41. Preferably, the contact arm 15 is formed into an L shape so that a lower side of the contact arm 15 rests against the floor upon which the base 11 rests.

Advantageously, the use of an L shaped contact arm 15 allows the contact arm 15 to be placed under an object 41 resting upon the ground. The stabiliser 16 is arranged to contact at an upper region the object 41 being lifted thereby stabilising the object 41 during elevation.

When the present invention is vertically oriented and used to lift a planar object such as a door, the door can then be elevated by actuation of the trigger 20.

Advantageously, the stabiliser 16 contacts an upper region of the door and provides stability during the vertical elevation of the door. Once raised to a desired height by a user, the door may remain elevated in a position allowing hinges to be attached to the door during installation. Since the present invention provides a directly vertical lift and acts to stabilise the door, installation is made easier.

A second preferred embodiment of the present invention will now be described with reference to Figures 6, 7, 8 and 9.

The second preferred embodiment of the present invention comprises a base 51, pair of support legs 52, 53 extending vertically upward from the base 51, a driving member 54 arranged between the two support legs 52, 53 and a jacking mechanism 55 located at an upper region of the support legs 52, 53 for moving the driving member 54 in an upward jacking direction away from the base 51 and permitting movement in a downward release direction toward lo the base 51. In addition, the second embodiment of the present invention comprises a contact arm 56 located at a lower region of the driving member 54 for in use lifting an object.

The jacking mechanism 55 of the second preferred embodiment is shown in detail in Figure 8. The jacking mechanism comprises a trigger 81 arranged to move about a pivot 82. Three gripping plates 83a-83c rest upon and are actuated by the trigger 81. A handle 84 is provided to aid the user in operating the trigger 81. The trigger 81 and gripping plate 83a-83c are normally biased by a first spring 85 in a first position approximately perpendicular to the longitudinal axis defined by the driving member 54.

In addition, a locking catch 86 is arranged to prevent movement of the driving member in a downward direction.

The locking catch 85 is biased by a second spring 87 in a position acutely angled with respect to the longitudinal axis.

In common with the first preferred embodiment, movement of the trigger 81 between a first downward position and a second upward position causes the gripping plates to actuate between being perpendicular to and acutely angled with respect to the longitudinal axis. In doing so, the gripping plates 83a-83c are caused to bite or grip and drive upward the driving member 54. In this manner, the driving member 54 and contact arm 56 are caused to move upward by operation of the jacking mechanism.

Advantageously, the use of three gripping plates 83a- 83c provides an increased level of bite or grip into the lo driving member 54. In this way heavier loads can be lifted by the device.

The driving member 54 passes through an aperture in the locking catch 86, in common with support leg 12 of the first preferred embodiment. When the locking catch 86 is angled acutely with respect to the longitudinal axis, the driving member 54 is prevented from moving in a downward direction toward the base due to top of one side and bottom of the other side of the locking catch aperture gripping the driving member 54. When the driving member 54 is gripped by the locking catch 86, repeated operation of the trigger 81 causes the driving member 54 to be ratcheted upward through the jacking mechanism 55. In this way, the contact arm 56 moved by the driving member 54 is also raised so as to in use to move an object.

The second preferred embodiment of the present invention further comprises a stabiliser 57 located at an intermediate region of the support legs 52, 53. As with the first embodiment of the present invention, the stabiliser 57 is arranged to, in use, contact an object being lifted and provide stability. The stabiliser 57 may be a polymer or rubber block, which does not damage the object.

The second preferred embodiment also has a pinch brake 58 located at an intermediate region of the supporting legs 52, 53 to retard movement of the driving member 54.

The pinch brake 58 comprises a pair of opposed brake members 59, 60 arranged either side of the driving member 54. An elongate shaft 61 passes through an aperture in each brake member 59, 60. A first end of the shaft 61 is prevented from travailing through the aperture by a shaft end 62 which is of a greater diameter than the aperture.

A cam is provided at a second shaft end 61. The cam is arranged to rotate about an axis transverse to the shaft axis so as to move between a position exerting a compressive force between the brake members 59, 60 and a position in which no force is exerted. In this way, the opposed brake members 59, 60 can be arranged to bear against and retard movement of the driving member 54 and contact arm 55. Advantageously, the pinch brake 58 allows a load to be lowered in the release direction in a controlled manner.

The second preferred embodiment of the present invention also comprises a guide block 63 arranged around the support legs 52, 53 at an intermediate region of the support legs 52, 53. The driving member 54 passes through the guide block 63, which guides the driving member 54 in its longitudinal motion. The guide block 63 is made from a polymer material such as nylon to reduce friction.

As shown in Figure 10, a pair of wheels 70 may also be provided at the base 51, arranged such that they do not contact the ground when the device is vertically oriented.

The wheels 70 are provided upon a pair of arms 71 so as to s allow the wheels to rotate freely. Advantageously, the second preferred embodiment may be reclined in use to rest upon the wheels 70, which enables the present invention, and an object elevated by the present invention, to be moved across the ground.

In addition, as shown in Figure 11, the stabiliser may be a roller 110, arranged to protrude upon a pair of arms 111 from the support legs 52, 53 and contact the object during lifting. The roller 110 may also be made from a polymer material. In this arrangement, the roller would be oriented to roll in a transverse axis with respect to the longitudinal axis, so as to roll against an object being jacked. Advantageously, the roller allows an object being lifted to rest against the roller and move in a vertical direction with minimal friction.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification

lo (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features

disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims 1. A manually operated jacking device, the device comprising: a

support; at least one elongate member extending from the support in a longitudinal direction; an elongate driving member arranged in use to move in the longitudinal direction relative to the elongate member; a contact member constrained to move with the driving member and arranged in use to engage an object to be jacked; wherein a jacking mechanism distal from the support is arranged, in a jacking condition, to move the driving member and the contact member in a jacking direction with the contact member moving relative to the support and, in a release condition, the driving member and contact member are able to move relative to the support in a direction opposed to the jacking direction.
2. The device according to claim 1, wherein: in the jacking direction, the contact member moves away from the support, and in the release condition, the contact member is able to move toward the support.
3. The device according to claim 1, or 2, wherein: the jacking mechanism moves relative to the at least one elongate member.
4. The device according to claim 3, wherein: the driving member is constrained to move with the jacking mechanism.

lo
5. The device according to any of claims 1 to 4, wherein the jacking mechanism comprises: a trigger arranged to move in the region of the jacking mechanism; at least one gripping member having an opening through which the elongate member passes and which is arranged in the jacking condition to move the jacking mechanism; wherein the at least one gripping member is actuated by movement of the trigger in a first direction.
6. The device according to claim 5, wherein: the at least one gripping member comprises an aperture through which the elongate member passes; and the at least one gripping member aperture is suitably larger than the elongate member so that the gripping member is in the jacking condition when angled acutely with respect to the longitudinal axis.
7. The device according to claim 5 or 6, wherein: the elongate member has a substantially rectangular cross-section; and the at least one gripping member is arranged to grip against opposing faces of the elongate member.
8. The device according to any preceding claim, wherein the jacking mechanism comprises: a locking member having an opening through which the elongate member passes, wherein the locking member is normally arranged in a locking condition to prevent the release condition being applied.
9. The device according to claim 8, wherein: the locking member is moveable relative to the jacking mechanism into the release condition.
10. The device according to claim 8 or 9, wherein: the elongate member passes through an aperture in the locking member; the locking member is arranged to pivot between the locking condition and the release condition; and the locking member aperture is suitably larger than the elongate member so that the locking member is in the locking condition when angled acutely with respect to the longitudinal axis and is in the release condition when angled substantially perpendicular to the longitudinal axis.
11. The device according to claim 1, wherein: in the jacking direction, the contact member moves toward the jacking mechanism, and in the release condition, the contact member is able to move away from the jacking mechanism.
12. The device according to claim 11, wherein the jacking mechanism comprises: a trigger arranged to move in the region of the jacking mechanism; at least one gripping member having an opening through which the driving member passes and which is arranged in the jacking condition to move the driving member and the contact member; wherein the gripping member is actuated by movement of the trigger in a first direction.
13. The device according to claim 12, wherein: the at least one gripping member comprises an aperture through which the driving member passes; and the at least one gripping member aperture is suitably larger than the driving member so that the gripping member is in the jacking condition when angled acutely with respect to the longitudinal axis.
14. The device according to claim 12 or 13, wherein: the driving member has a substantially rectangular cross-section; and the at least one gripping member is arranged to grip against opposing faces of the driving member.

lo
15. The device according to any of claims 12 to 14 wherein: the gripping member and the trigger are arranged such that reciprocating movement of the trigger causes the gripping member to reciprocate between being substantially perpendicular to the longitudinal axis and the jacking condition, thereby moving the driving member and contact member when in the jacking condition.
2016. The device according to any of claims 12 to 15, wherein the jacking mechanism comprises: a locking member having an opening through which the driving member passes, wherein the locking member is normally arranged in a locking condition to prevent the release condition being applied.
17. The device according to claim 16, wherein: 30the locking member is moveable relative to the jacking mechanism into the release condition.
18. The device according to claim 17, wherein: the driving member passes through an aperture in the locking member; 5the locking member is arranged to pivot between the locking condition and the release condition; and the locking member aperture is suitably larger than the driving member so that the locking member is in the lo locking condition when angled acutely with respect to the longitudinal axis and is in the release condition when angled substantially perpendicular to the longitudinal axis.
519. The device according to any of claims 8 to 10 or 16 to 18, wherein: the trigger is arranged to reciprocate between the first position and a second position in order to effect the jacking condition whilst the locking member prevents the release condition being applied.
20. The device according to any of claims 5 to 10 or 12 to 19, comprising at least three gripping members.
21. The device according to any of claims 5 to 10 or 12 to 20, wherein: the at least one gripping member is a gripping plate.
22. The device according to any of claims 5 to 10 or 12 to 21, comprising: a resilient biasing means to bias the trigger in a first position.
23. The device according to any of claims 8 to 10 or s 16 to 22, the jacking mechanism further comprising: a resilient biasing means to normally bias the locking member in the locking condition.

lo
24. The device according to any claims 8 to 10 or 16 to 23, wherein the locking member is a locking plate.
25. The device according to any preceding claim, comprising: a stabilising member arrangable in use to stabilise an upper region of the object to be jacked.
26. The device according to claim 25, wherein the stabilising member is a polymer member.
27. The device according to claim 25 or 26, wherein: the stabilising member is a roller arranged to rotate about an axis transverse to the longitudinal axis.
28. The device according to any preceding claim, comprising: a retardation means for exerting a retarding force upon the driving member.
29. The device according to claim 28, wherein the retardation means is adjustable by a user to exert an adjustable retarding force.
30. The device according to claim 29, wherein the retardation means comprises: a first brake member and a second brake member arranged either side of the driving member; a means for applying an adjustable force between the first and second brake members.
31. The device according to any preceding claim, comprising a handle.
32. The device according to any preceding claim, arranged in use to elevate a planar object.
33. The device according to any preceding claim arranged in use to elevate a door.
34. A method of jacking an object, comprising the steps of: supporting a jack; engaging an object with a contact member of the jack; operating a jacking mechanism in a jacking condition so as to move a driving member and the contact member in a jacking direction relative to the support; operating the jacking mechanism in a release condition so as to allow the driving member and the contact member to move relative to the support in a direction opposed to the jacking direction.
35. The method according to claim 34, wherein in the jacking direction, the contact member moves away from the support, and in the release condition, the driving member and contact member are able to move toward the support.
36. The method according to claim 34 or 35, wherein the step of operating the jacking mechanism comprises moving the jacking mechanism away from the support.
37. The method of claim 36, wherein the driving member and contact member move in co-operation with the jacking mechanism.
38. The method according to claim 34, wherein in the jacking direction the driving member and the contact member move toward the jacking mechanism, and in the release condition, the driving member and contact member are able to move away from the jacking mechanism.
39. The method according to any of claims 34 to 38, comprising the step of stabilising an upper region of the object.
40. The method according to any of claims 34 to 39, wherein: the jacking mechanism is operated in the jacking condition by reciprocating a trigger between first and a second position.
41. The method according to any of claims 34 to 40, wherein: the jacking mechanism is operated in the release condition by movement of a locking member relative to the lo jacking mechanism.
42. The method according to any of claims 34 to 41, comprising the step of applying a retarding force to the driving member.
43. The method according to claim 42, comprising the step of adjusting the retarding force applied to the driving member.
44. The method according to any of claims 34 to 43, comprising the steps of: wheeling the jack into a position suitable for jacking the object; jacking the object.
45. The method according to any of claims 34 to 44, wherein the object is a door, the method comprising the steps of: jacking the door into an elevated position; installing the door; releasing the jack.
46. The method according to any of claims 34 to 45, wherein the object is a laminate type flooring material, the method comprising the steps of: jacking flooring material into a position suitable for lo installation; installing the flooring material; releasing the jack.
47. A method of operating a jack, suitable for use with the device according to any of claims 1 to 33.
48. A device substantially as hereinbefore described with reference to the accompanying drawings.
49. A method substantially as hereinbefore described with reference to the accompanying drawings.