JACK

Background of the Invention

The present invention relates to a device for controlling the separation between two surfaces or objects, and in particular, to a propping or jacking device which can prop or jack an object above a substrate surface and retain it in an elevated position.

The present invention has particular application to jacking vehicles or heavy machinery, which is traditionally firstly jacked up and then, secondly, packing material is supplied thereunder, such that persons or other equipment may thereafter work below the elevated vehicle, machinery or other object.

Description of the Prior Art

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

At present, to perform maintenance and repair of heavy machinery, such as in earthmoving and mining applications, when it is necessary for a person and or service equipment to access the underside of the machinery to be repaired, jacks are normally used.

Such jacks are typically hydraulic or pneumatic jacks, which rely on fluid being maintained under constant high pressure. Once the equipment is jacked up, maintenance personnel typically move under the machinery to carry out the required repair work. Such hydraulic systems are known to occasionally fail, or leak, which could result in a slow or sudden failure of the system, with potentially catastrophic effects.

This can have occupational health and safety implications, and in many situations, can be quite dangerous. In some situations, maintenance and repair personnel may spend considerable time, typically hours, in this hazardous environment below a heavy load, with only a hydraulic system keeping the machinery in place. The risk can be further enhanced

in many outdoor environments, for example in windy situations, where the machinery is at a fairly high risk of being blown, slipping, or otherwise falling over.

In some situations, this risk may be somewhat minimised, by using packing. That is, after the one or more jack initially lifts the huge machinery to the required elevation, a packing material may be installed thereunder. The packing material suspends the equipment in the elevated position, such that service personnel and maintenance equipment may move about under the elevated equipment. The aforementioned risk is therefore minimised somewhat, as the personnel are only in high danger for as long as it takes them to install the packing material. Once the maintenance or repair work is completed, the jacks then re-elevate machinery, such that personnel can then remove the packing material, and the equipment may then be lowered to its normal operational position. The personnel are therefore again placed at risk during this packing removal operation.

Summary of the Invention

The present invention seeks to overcome the disadvantages of these prior art hydraulic jacking devices.

The present invention also seeks to provide a device for controlling the separation between two surfaces, such as a substrate surface and the underside surface of a machinery, which has improved safety features over the known prior art devices.

In one broad form, the present invention provides a jacking device, including: a base member, adapted to engage a substrate surface; a movable member, movable relative to said base member, having an upper surface adapted to engage an object to be raised or lowered; a threaded shaft associated with either said base member or said movable member; a guide means associated with the other of said base member or said movable member, said guide means including a threaded surface which is adapted to cooperate with said threaded shaft; and drive means, adapted to rotate said threaded shaft and/or said guide means such that said movable member is permitted to be moved relative to said base member to thereby raise or lower said upper surface.

Preferably, when said drive means is in an inoperative state, said device is in a locked position, whereby relative movement between said guide means and said threaded shaft is prohibited, and said movable member is thereby prevented from movement.

Also preferably, the jacking device includes a plurality of threaded shafts and associated guide means are provided.

Preferably, said drive means is adapted to rotate each of said threaded shafts and/or said associated guide means via appropriate gears, chains, drive train or like mechanical means.

Also preferably, said base member includes a lower surface adapted to engage said substrate surface, and, at least one sidewall extending upwardly therefrom, and, said movable member includes at least one sidewall extending downwardly from said upper surface thereof, whereby said sidewalls of said base member and said movable member cooperate to guide the movement of said movable member relative to said base member.

Preferably, said sidewall(s) of said base member is/are guided inside said sidewall(s) of said movable member, or vice versa.

Preferably, said drive means includes a motor.

Also preferably, said drive means is housed within or external to a housing including said base member and said movable member.

Preferably, said housing is, in cross-section, substantially square, rectangular, circular or other geometric shape.

Also preferably, said drive means further includes: hydraulic and/or pneumatic means, adapted to move said movable member relative to said base member.

In a further broad form, the present invention provides a jacking device, including: a base member, adapted to engage a substrate surface; a movable member, movable relative to said base member, having an upper surface adapted to engage an object to be raised or lowered; a threaded shaft associated with either said base member or said movable member; a guide means associated with the other of said base member or said movable

member, said guide means including a threaded surface which is adapted to cooperate with said threaded shaft; and drive means, including: hydraulic and or pneumatic means, adapted to move said movable member relative to said base member; and, motor means, which, when in a first state, is adapted to rotate said threaded shaft and/or said guide means as said hydraulic and/or pneumatic means moves when in a second state, prohibits movement of said movable member relative to said base member. In yet a further broad form, the present invention provides a propping device, including: a first member, adapted to engage a first surface; a second member, movable relative to said first member, adapted to engage a second surface; a threaded shaft associated with said first member; a guide means associated with said second member, said guide means having a threaded surface which is adapted to cooperate with said threaded shaft to prop said first member apart from said second member; and, drive means adapted to rotate said threaded shaft and/or said guide means, such that said second member is movable relative to said first member.

Brief Description of the Drawings

The present invention will become more fully understood from the following detailed description of preferred, but non-limiting embodiments thereof, described in connection with the accompanying drawings wherein:

Fig. 1 illustrates the use of three jacks, each made in accordance with a preferred embodiment of the present invention, lifting heavy machinery;

Fig. 2 illustrates cross-sectional view of the front and side elevations of a jacking device as shown in Fig. 1 ; Fig. 3 illustrates details of the upper and lower frames, in Figs. 3a and 3b respectively, with Fig. 3a showing front, side and plan views of the upper frame, and Fig.

3b showing front, side and plan views of the lower frame of the jacking device illustrated in Fig. 2;

Fig. 4 illustrates a different embodiment of a jacking device, showing a different arrangement of the various features thereof; and Fig. 5, illustrates in Figs. 5a and 5b, details of an air or hydraulic motor which may be utilised to drive the threads of the jacking device, Fig. 5a showing a plan view thereof, and Fig. 5b showing an elevational view thereof.

Detailed Description of Preferred Embodiments Throughout the drawings, like numerals will be used to identify similar features, except where expressly otherwise indicated.

As shown in the drawings, the jacking device, generally designated by the numeral

1 may, in its preferred embodiment, be used for jacking vehicles or heavy machinery 2 to an elevated position above a substrate surface 3, such that the vehicle or machinery 2 or other object which is jacked up can be raised to a position where a person or persons and appropriate service equipment may be provided thereunder to access the underside of the machinery 2 to be repaired.

The jacking device 1 of the present invention differs from the prior art in that it combines the ability to jack the heavy machinery 2 to its elevated position, and also to effectively simultaneously provide packing under the heavy machinery 2, to ensure that the heavy machinery 2 stays in its elevated position as is not liable to fall.

The jacking device I ₅ includes a base member 4, further details of which are shown in Fig. 3b, and a movable upper member 5, the further details of which are shown in Fig.

3a. The base member 4 has a lower surface 6 which is adapted to engage a substrate surface 3. The movable upper member 5 is adapted to be movable relative to the base member 4, and has an upper surface 7 which is adapted to engage the machinery 2 or other object to be raised or lowered.

Movement of the upper or movable member 5 relative to the base member 4 is achieved by provision of one or more threaded shaft 8. The number of threaded shafts to be used will largely depend upon the extent of the load which is required to be moved by the jack, as this allows the load to be spread, as will be appreciated by persons skilled in

the art. Each threaded shaft 8 has a guide means 9 which cooperates with the threaded shaft 8. The combination of the threaded shaft 8 and the guide means 9 effectively enables the locking of the movable member 5 relative to the base member 4. A drive means 10 is provided to rotate the threaded shaft 8 and/or the guide means 9 such that the movable member 5 is permitted to move relative to the base member 4 to thereby raise or lower the upper surface 7. The drive means 10 may be an electric, hydraulic and/or pneumatic drive means to either drive the threaded shafts, the guide means, or both. The drive means 10 may alternatively separately control the raising and lowering of the upper surface 7, using, for example, a hydraulic or pneumatic system, whilst a separate portion of the drive means 10 using, for example, an electromechanical system, may rotate the threaded shaft or guide means.

In one form of implementation, such as shown in Fig. 4, the drive means 10 may be installed beneath the threaded shaft 8 and adapted to rotate the threaded shaft 8 as desired. That is, when the drive means 10 is in an inoperative state, the device is effectively in a locked position, whereby relative movement between the guide means and the threaded shaft is prohibited, and movement of the movable member 5 is thereby effectively prevented.

A plurality of threaded shafts and associated guide means 9 may be provided, and these may be operatively interconnected by an appropriate gearing, chain, drive train or like mechanical or other means. An example of the interconnection between a plurality of threaded shafts 8 is shown in Fig. 5 whereby each of the threaded shafts 8 is interconnected via a chain 11.

As illustrated in Fig. 4, the base member 3 preferably includes a lower surface 6 which is adapted to engage a substrate surface 3 and a plurality of side walls 12 extending upwardly therefrom. The movable member 5 preferably also includes a plurality of side walls 13 extending downwardly from the upper surface 7. The configuration of the side walls 12 of the base member 4 and the side walls 13 of the upper or movable member 5 is such that they cooperate to guide the movement of the movable member 5 relative to the base member 4. This may be achieved such as shown in Fig. 2 wherein the upper member walls 13 fit within the lower member walls 12, or vice versa as shown in Fig. 4, where the upper member walls 13 fit outside the lower member walls 12. Either way, the respective

side walls of the upper and lower members should cooperate. The housing may be square, rectangular, circular or any other geometric shape.

As previously mentioned, the drive means may be embodied as a motor. The drive means may be housed either internally or externally from the housing formed by the base and movable members. For example in Fig. 4, the drive means 10 is shown internally of the housing, whilst in Fig. 1 , it can be seen that the drive means can be housed in a separate compartment external to the base member. The drive means may be an electric motor, a hydraulic or pneumatically driven drive means or any combination of these. As previously mentioned, the drive means can control not only the raising and lowering of the movable member, but also the locking engagement of the movable member relative to the base member such that it is retained safely when in an elevated position supporting the heavy machinery or the like. This may be achieved by the drive motor 10 such as shown in Fig. 4 controlling the operation of the drive thread by driving the thread through the guide means or holding nuts 9 such that the upper surface 7 of the movable member 5 is raised or lowered. When operation of the drive means 10 is stopped, the upper surface 7 cannot further move. It will be seen that by the combined use of the thread and the guide nuts, no accidental movement of the upper surface is permitted without operation of the drive motor 10. This therefore effectively locks the jack such that it cannot be moved without further driving the drive means 10. In another preferred version, the drive motor may simply be a motor which has enough power to rotate the threads 8 when a hydraulic system, pneumatic system or other means is used to raise or lower the upper surface 7 of the jacking device 1. The drive motor is therefore driven such that as the hydraulic or other lifting system operates, the thread moves within the guide nuts 9 to a new position. Once the desired position is achieved, the thread and nuts interconnection effectively locks the device into position such that no further movement is prevented.

It will be therefore understood by persons skilled in the art that once in its locked position, in the event that any basic hydraulic system which are known to occasionally fail or leak, or cause sudden or slow failure of the system should be overcome. Maintenance and repair personnel and equipment can therefore be safely brought underneath the heavy load, with the risk of any accidental falling of the load substantially minimised.

It will be appreciated by persons skilled in the art that numerous variations and modifications may be made to the jacking device as hereinbefore described. It will also be appreciated that a device which functionally operates in the same manner may be utilised in other than in jacking positions. Specifically, the device could be used to prop any two objects or surfaces apart in other than vertical dispositions.

All such variations and modifications which become apparent to persons skilled in the art should be considered to fall within the spirit and scope of the invention as broadly hereinbefore described and as hereinafter claimed.