15161INN ORIGINAL Innovation Specification Applicant: William Campbell Title: A wheel jack Address for Service: LESICAR PERRIN, 49 Wright Street, Adelaide, South Australia 5000, Australia The following statement Is a full description of this invention, including the best method of performing it known to me/us: 2 A WHEEL JACK The present invention relates to a wheel jack for assisting in changing a vehicle wheel, in particular a wheel jack which assists in lifting and positioning a vehicle wheel into position for installing on, or removal from, a vehicle hub. s BACKGROUND OF THE INVENTION The task of changing the wheel of a vehicle is made physically arduous by the need to lower the wheel from the vehicle hub to the ground during removal, and the need to raise the replacement wheel from the ground to the vehicle hub. This problem has been long recognised and various types of tools and apparatus 10 have been produced to address the problem. The prior art solutions consist mostly of simple levers or dollies. The prior art levers come with one or two fulcrums, located at either the end of, or part way along their body. The levers are cumbersome to use as the user needs to manipulate the lever and wheel simultaneously. This is particularly difficult for levers 15 with a single fulcrum. Levers with fulcrums part way along their body can often be knee operated, but this requires the user to have a high level of coordination. Such devices are therefore not particularly suitable for use by the elderly for example. The prior art dollies are also often large and complicated pieces of equipment. This makes them expensive to manufacture and unsuitable for use outside of a 20 workshop. The object of this invention is to provide a wheel jack that alleviates the above problems, or at least provides the public with a useful alternative. SUMMARY OF THE INVENTION In a broad aspect the invention could be said to reside in a device for raising and 25 lowering a wheel comprising: 3 a base; an upright screw thread associated with said base and including a longitudinal axis, said screw thread being rotatable about said longitudinal axis; a lifting platform for supporting said wheel, said lifting platform including a hook 5 means; an attachment member associated with said upright screw thread, said attachment member being rotatable about said screw thread longitudinal axis and adapted to receive said hook means and thereby support said platform; and a means for rotating said screw thread to thereby raise or lower said platform relative 10 to said base. Preferably said attachment member is a rigid body including an internally threaded aperture adapted to rotatably engage said upright-haf4 screw thread, and shaft portions extending transversely outwardly from said body, said shaft portions being of lesser cross sectional dimension. 15 In preference said platform includes a front floor portion upon which said wheel is supported, and a rear wall portion extending perpendicularly to said floor portion, said hook means being in the form of two spaced apart hooks associated with said rear wall portion and adapted for engagement with said attachment member shaft portions, wherein when said platform and attachment member are engaged, the floor portion 20 extends on a forwards angle to facilitate handling of said wheel to and from said platform. Preferably said screw thread terminates at its top end in an upright lug with an aperture extending there through, and said means for rotating said screw thread is in the form of a shaft passing through said aperture, said forwards angle of said platform 25 facilitating rotation of said h-anleshaft. In preference said screw thread terminates at its top end in a nut, and said means for rotating said screw thread is in the form of a ratchet handle adapted to engage said nut, said forwards angle of said platform facilitating rotation of said ratchet.
4 BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various implementations of the invention and, together 5 with the description, serve to explain the advantages and principles of the invention. In the drawings: Figure 1 illustrates a perspective view of a wheel jack according to a first embodiment of the present invention; Figure 2 illustrates the hidden features of Figure 1; 10 Figure 3 illustrates how the platform of the wheel jack of Figure 1 is mounted to the platform support; Figure 4 illustrates the attachment between the platform and the platform support of Figure 3; Figure 5 illustrates the rotational freedom of the lifting platform of the wheel 15 jack of Figure 1; Figure 6 illustrates the wheel jack of Figure 1 disassembled; Figure 7 illustrates the wheel jack of Figure 1 situated in use with a vehicle; Figure 8 illustrates the use of the wheel jack of Figure 1; and Figure 9 illustrates the use of a wheel jack in accordance with a second 20 embodiment of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described 5 without departing from the spirit and scope of the invention. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity 5 or illustration. Figure 1 illustrates the main features of the wheel jack 10 of the invention. The wheel jack comprises a base 20, threaded shaft 30, lifting platform 40, attachment member 50, and handle 60. Figure 2 shows further features of the base 20 which comprises a rectangular plate 10 22 and a shaft support 24. The shaft support 24 is a pipe with an internal diameter slightly larger than the external diameter of the threaded shaft 30. The shaft support has two ends, 26 and 28. The first end 26 is fixedly attached to the base 20. The second end 28 is open to receive the threaded shaft. The full length of the shaft support envelopes the threaded shaft. The threaded shaft fits loosely into the shaft 15 support to facilitate rapid and simple assembly and disassembly of the wheel jack. The threaded shaft 30 has an upstanding lug 32 at one end with a horizontally extending circular aperture 34 therethrough. The handle 60 consists of a shaft 62, which fits through the aperture 34 of the threaded shaft, and bulbous ends 64 which will not. The handle can thus slide back and forth through the aperture but is still 20 constrained by it. The lifting platform 40 consists of a bottom plate 42, a side plate 44 and attachment hooks 46. The bottom plate is used to support a wheel. Referring now to Figures 2, 3 and 4, the attachment member 50 comprises an elongate body 52, circular shafts 54 extending outwardly from opposite ends of the 25 body and end caps 56. The body of the attachment member has an internal thread which corresponds to the external thread of threaded shaft 30, thus enabling rotatable engagement between the attachment member and the threaded shaft. The shafts of the attachment member are used to support the attachment hooks 46 of the lifting 6 platform 40. The circular cross section of the shafts provides rotational freedom for the lifting platform as shown in Figure 5. The rotational freedom allows a wheel on the wheel jack to be manipulated when fitting to or removing from a vehicle as well as clearance space for the handle as it is used to rotate the shaft. The use of attachment 5 hooks also facilitates rapid and simple assembly and disassembly of the wheel jack. In an alternative configuration the shafts of the attachment member and attachment hooks of the lifting platform have a non-rectangular cross section so as to prevent rotational freedom of the lifting platform. For example, the cross section of the shafts and the shape of the hooks could be square shaped and, to create the 10 desired angle in the platform to facilitate mounting and removal of the wheel, the square shafts could be configured to have a forward tilt. In fact, such shafts could be made to be rotatable about the longitudinal axis of the attachment member, thus allowing the lifting platform to be fixed at various angles. As the threaded shaft 30 is rotated by the handle 60, the attachment member 50 15 will move linearly along the threaded shaft and thus raise or lower the lifting platform 40. As shown in Figure 6, when not in use the wheel jack can be partially disassembled to minimize storage space requirements, Figure 7 and 8 shows the wheel jack 10 in use with a wheel 12 belonging to a 20 vehicle 14 being supported by a vehicle jack 16. To remove a wheel from the vehicle, the wheel jack is first placed in position under the wheel. The handle 60 is turned in a first direction which in turn rotates the screw thread 30. The rotation of the screw thread raises the lifting platform 40 upwards until the platform comes in contact with the wheel. The wheel is then 25 detached from the vehicle. The handle is then turned in a second direction which lowers the platform and wheel downwards to the ground. The wheel can then be rolled off of the wheel jack and replaced with a replacement wheel.
7 To fit the replacement wheel to the vehicle, the handle is again turned in the first direction to raise the platform and wheel upwards. When the wheel is at a suitable level it can then be attached to the vehicle. The handle is then turned in the second direction to lower the platform until it is clear from the wheel. The wheel jack can 5 then be removed. In an alternative embodiment shown in Figure 9 the handle 60 and lug 32 are replaced with a ratchet handle 60'. Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown 10 and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. 15 In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.