Method and apparatus for removing and installing a differential of a vehicle

A hoisting assembly that is adapted to be mounted to the frame of a vehicle where a hoisting device extends an attachment member such as a hook to connect to an engagement location of the differential where the hoisting assembly is positioned substantially vertically above the differential and when the hoisting assembly supports a differential the load is transferred to the frame of the vehicle.

BACKGROUND OF THE INVENTION

a) Field of the Invention

The invention relates to a method and apparatus for removing and installing a differential from and to a vehicle where the differential and a hoisting assembly supporting the differential are supported by the frame of the vehicle.

b) Background Art

The prior art disclosures are primarily directed toward supporting a differential by applying a force to elevate and support the differential where the surrounding ground surface is the primary direct area for support. For example, the following prior art referenced as are discussed herein below.

U.S. Pat. No. 6,322,061 (Maser et al) discloses a “Universal Axle and Differential Carrier Stand”. The disclosure shows a wheeled base frame having two upper horizontal support rails12to which are mounted vertically aligned support arms24which are adjustably mounted by sliding supports25. At the upper end of these arms are a pair of axle clamp assemblies30which fit into the members24so that these can be placed at different elevations.FIG. 3shows the apparatus supporting the differential70.

U.S. Pat. No. 5,566,999 (Goettl) relates to a particular type of mechanism by which the differential can be lifted. In column 1, under “Background of Invention,” beginning on line 36, it is stated that it is a common practice to weld a lifting eye or loop to an exterior of the case of the differential, and this can be used to accept the hook of a hoist. It is indicated that this is done by welding, and this can weaken the case of the differential at that point. The disclosure is directed to the particular type of hoist attaching mechanism, and this comprises upper and lower jaws20and22which grip the flange of the differential, and there are also various bolt connections.

Other US patents disclose various methods of supporting a differential such as U.S. Pat. No. 4,570,905 (Gerstner) shows a floor jack attachment which is intended to be used as a means to hold and move a differential. U.S. Pat. No. 4,549,722 (Gagliano) shows a floor jack that is intended to be used to support a differential as it is removed. U.S. Pat. No. 3,559,981 (Abshear) shows a wheeled device that is secured to a differential, and used to remove it from the housing.

U.S. Pat. No. 3,012,311 (Shupe) provides yet another differential support intended to be secured to a jack on the floor. U.S. Pat. No. 2,903,258 (Jonanovich) shows a repair stand that may be secured to a floor jack to move the differential about the shop. Finally, U.S. Pat. No. 2,748,459 (Orr) shows a jack attachment intended to support a differential.

SUMMARY OF THE INVENTION

In general the invention relates to a hoisting assembly for removing a differential that is adapted to be mounted on a frame of a vehicle. The vehicle having a differential that is adapted to be attached thereto the hoisting assembly. The hoisting assembly has a central frame having first and second lateral ends and a central area. A hoisting device is adapted to be mounted to the central area of the central frame. The hoisting device comprising an attachment member that is adapted to be mechanically attached to the differential of the vehicle.

The hoisting device is adapted to raise the attachment member vertically and the differential attached thereto and support the differential where the central frame is positioned substantially vertically above the differential.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following is a detailed description of an embodiment of the hoisting assembly20. The various components of the hoisting assembly are discussed further herein following a description of the general operating environment. To aid the description an axis system is defined where as shown inFIG. 1, the axis system10comprises a lateral axis12and a longitudinal axis14. As shown inFIG. 2, the axis system10further comprises a vertical axis16. The various axes are put forth to describe the general relationship of the components and are not intended to limit the apparatus in any specific orientation. Further, the axes denotes a general direction and substantial orthogonal directions with respect to one another.

The general environment of the hoisting assembly20is for removal and replacement of a differential and differential housing. As shown inFIG. 1, there is a portion of a vehicle22. The vehicle22such as a truck comprises a frame24and axle assembly26. The frame24as a first lateral frame section28and a second lateral frame section30. The frame24further comprises an upper surface32. The frame24further has first and second outer vertical surfaces34and36positioned on the first and second frame sections28and30respectively and outward surfaces33and35. The axle assembly26comprises a central axis member40and wheel assemblies42positioned in the laterally outward portions of the central axis member40. The central axis member40further has a circular flange region44(banjo housing of the truck rear axle) with a plurality of connection locations46. In one form, the connection locations are a threaded recessed region adapted to engage bolts48. Normally, a plurality of bolts spaced around the outer circumference area are employed to securely attach the differential50thereto.

As shown inFIG. 4, the differential50comprises a housing section52and a flange region54. The flange region54has a plurality of connection locations56that when in a mounted position, correspond in location to the connection locations46of the flange region44of the axle40. The connection locations56are generally surfaces defining circular openings that are adapted to allow the bolts48to extend therethrough and fasten the differential50to the axle40. As described further herein, in one form an engagement location58is defined which is one of the connection locations56that is preferably that the vertically upper location. The engagement location is adapted to support a vertical force to support the differential50and is adapted to engage with the attachment member104described further herein.

The differential50further comprises a longitudinally forward region having a smaller diameter circular flange60which in normal practice a clevis extends therefrom. The clevis is generally coupled to a drive shaft which is not shown in the figures.

There will now be detailed discussion of the hoisting assembly20with initial reference toFIG. 3. As shown in this figure, the hoisting assembly20comprises a central frame70and a hoisting device72. The central frame70comprises a first lateral end74and a second lateral end76. The central frame further has a central area78. In one form, the central frame70is constructed from square tubular material such as steel. As shown inFIG. 1, the central frame70comprises first and second longitudinally extending members80and82which are located in the first and second lateral end locations74and76respectively and a laterally extending member71. In one form, the longitudinally extending members80and82are rigidly attached (e.g. welded) to the laterally extending portion of the central frame70.

In one form, end portions84and86are positioned in the first and second lateral locations74and76. The end portions84and86each have lateral inward surfaces88and90that are adapted to engage the lateral outward surfaces33and35of the frame24. The laterally extending member71and the longitudinally extended members80and82collectively provide a lower support surface92. The lower support surface has a first lateral subregion94and a second lateral subregion96. The lateral subregions94and96are particularly adapted to engage the upper support surface32of the frame24. The lower support surface92further has a perimeter region that is defined as the outer boundaries of the support surface that can support a load and not topple the hoisting assembly20. It should be further noted that the subregion surfaces94and96are adapted to engage in the longitudinal direction where the support from the central frame70positioned sufficiently broad enough in the horizontal plane to support the action of the hoisting device72described further herein.

The hoisting device72is attached to the laterally extending member71of the central frame70. As shown inFIG. 3, in one form the hoisting device72can be repositioned along the central region78of the central frame70. By repositioning these hoisting device70in the lateral direction, this aids in providing a vertical lift and getting around portions of the vehicle that may be in the way when the hoisting assembly20is an operation.

As shown inFIG. 4, the hoisting device72comprises a power retraction system100, a cable102and an attachment member104. The power retraction system100is adapted to forcefully retract the cable102. In one form, this is a hand-cranked system employing a hand-crank107with conventional internal gearing mechanisms to supply sufficient leverage to draw in the cable102around an internal spool. Of course other mechanisms such as an electric motor that would run off the 12-volt supply, a ratcheting device, a removable handle that can be repositioned to reel in the cable112, or simply a nutlike extension adapted to receive a wrench for applying torque thereto, or any other method of retracting the cable102can be employed and are hereby defined under a hoisting device.

The cable102in one form is a metallic cable of sufficient strength to support a differential50with a factor of safety that is common in the industry. For purposes of definition in this application, a cable is defined as any flexible device adapted to support a load in tension such as a strap made a various materials such as nylon, Kevlar or other types of materials as well as a metallic type of flexible material like woven metal or chains and other flexible tension type members can be employed of various materials such as, polymers, or other devices to support a differential50can be employed.

Further, the cable and power retraction system could be in the nature of a linkage system where a linkage having an attachment member attached to one location is employed where a combination of levers give mechanical advantage to support the differential50and allow it to be removed or installed into the vehicle22in similar manner as the process described further herein. In one form the attachment member is a hooklike device but could further be other methods of connecting member such as a chain or other similar item that is adapted to wraparound a substantial portion of the differential to support it. Further, a connection device can be welded to the differential with a connection member adapted to connect thereto. Further, any other device that is adapted to securely mounted the end portion of the cable102to differential can function as the attachment member104and is hereby defined as such for the connection member.

The power retraction system is mounted to a housing component106(seeFIG. 3). In one form, the housing component106has an interior surface and cross-sectional open area slightly greater than the exterior surface of the laterally extending member71. The housing component106is adapted to reposition the power retraction system100laterally as shown by the hatched lines inFIG. 3. In one form, a locking mechanism can lock the hoisting device72to a particular lateral location. However, because there is a sufficient amount of vertical force when the hoisting device72is supporting a differential, and normally the upper surface32of the frame24is substantially in the horizontal plane, (at least substantially level in the lateral direction), the internal friction between the inner surface of the housing component106in the outer surface of the laterally extending member71is sufficient to prevent the hoisting device72from accidentally repositioning laterally in an undesirable and unexpected manner. Further, when the hoisting device72is supporting a differential such as that is shown inFIG. 5, the hoisting device72and the differential50can be repositioned laterally with respect to the central frame member70by nudging the hoisting device in a lateral direction with a shove or an impact such as a blow from a rubber mallet.

There will now be discussion of the removal process and method of the differential when employing the hoisting assembly with initial reference toFIG. 5. As shown in this figure, the hoisting assembly20is positioned substantially above the differential to be removed50. The term “positioned substantially above” or “positioned substantially vertically above” is defined as a vertically higher location which may not necessarily be directly above the differential but is merely defined as being positioned at a greater vertical elevation with respect to the differential50regardless of the horizontal position. The central frame70of the hoisting assembly20is positioned on the vehicle frame24. In one form, the hoisting assembly20is positioned on the vehicle frame24where the lower support surface92of the central frame70is positioned upon the upper support surface32of the frame24. Of course other methods of positioning the central frame70can be employed to mount the hoisting device20onto the frame24of the vehicle22. For example, the interior regions of the C channels that comprise the frame24can be used to support the central frame70of the hoisting assembly20and such methods are herein defined as mounting the hoisting assembly20to the frame24of the vehicle22.

When the central frame70is mounted to the frame24, it is held in place by the frictional forces between the surfaces of these frame members. Therefore, the hoisting assembly20can be repositioned in the longitudinal direction so the hoisting assembly20is substantially above the differential50as shown inFIG. 5.

To remove the differential50, the attachment member104is inserted into the engagement location58. In one form as mentioned above, the attachment member104is a hook like device that is attached to the cable102.

The power retraction system100of the hoisting device72is adapted to allow free extension of the cable102when desired by the operator, can further lock in place at a set length, and be retracted into the housing of the power extractor100forcefully (i.e. with sufficient tension to support the weight applied thereto) to generate tension in the cable102. After the attachment member104is secured to the engagement location58of the differential50, the power retraction system100is employed and the cable102is retracted or tension is applied thereto and a sufficient amount of vertical force is imparted upon the differential to counteract the weight of the same. Then the bolts48are removed as shown inFIG. 5and extracted from the connection locations of the differential50and the axle40.

Thereafter as shown inFIG. 6, the differential50is fully and totally supported by the hoisting assembly20. In one form, the attachment member104will extend through the open region of the engagement location58. However, depending upon the size of the attachment member104this may or may not occur in practice.

Now referring toFIG. 7, the hoisting device20is repositioned longitudinally forward with respect to the axle40and the frame24of the vehicle. In one form, this is accomplished where the lower support surface92of the central frame70simply slides upon the upper support surface32of the frame24. Of course, wheel assemblies or other lower friction devices can be employed such as an undercoating or another material can be attached such as a polymer plastic, nylon or the like to the under portions of the frame70of the hoisting assembly20. It has been found that the coefficient of friction between steel surfaces is sufficiently low that the hoisting assembly20can be repositioned with respect to the frame and slide thereon even with the weight of a differential50attached thereto. As shown inFIG. 7, the longitudinally extending members80and82(only82is shown in the partial cross-sectional view) assist in supporting the differential50so the center of gravity of the combination of the differential50and the hoisting assembly20is between the extreme area support location which is the surfaces of the perimeter region of the hoisting assembly20that includes the lower surfaces of the central frame70and the longitudinally extending members80and82. Further, as shown inFIG. 7as a cross-sectionally hatched hidden line, the end portions84and86(only end portion86is shown as a hidden line) help assist in refraining excessive lateral movement of the hoisting assembly20. This is primarily a safety device where the hoisting assembly will not repositioned laterally where one of the first or second lateral ends74or76will slide beyond the lateral interior most portion of the frame members whereby toppling the hoisting assembly and the supported differential. Of course this lateral movement can be impeded in a variety of ways, for example as shown inFIG. 3, a vertically downward extending member could be positioned on the interior portion of the frame24.

A repaired or new differential can be reattached to the axle40in a similar manner as the removal process but in the reversal of steps. To attach or install the differential to a vehicle, first the hoisting assembly20is positioned substantially vertically above (as also defined supra where the hoisting assembly is positioned at a vertical location greater than the vertical location of the differential irrespective of the horizontal location) and the attachment member104is attached to the attachment location of the differential. The hoisting assembly20is attached to the frame of the vehicle. In one form, the hoisting assembly rests upon the upper support surface32of the frame24of the vehicle. The attachment member is operatively connected to the cable102which in turn is connected to the hoisting device72. The hoisting device forcefully retracts the cable and supports the differential. The hoisting device has a vertical adjustment system where the length of the extracted cable is adjusted whereby adjusting the height of the differential with respect to the axis40. Thereafter, if necessary the hoisting assembly20and the differential50are repositioned in the longitudinal direction in a matter as shown inFIG. 6whereby the connection locations of the differential are substantially aligned with the connection locations of the axle40. Thereafter, as shown inFIG. 5fasteners such as bolts48are inserted.

It should be noted that in some forms there are two differentials on a truck which would be referred to as a front differential and a rearward differential. Of course the hoisting assembly20is adapted and well-suited to remove and replace either front or rear differentials were either are referred to as differentials.

Of course various modifications and changes can be made without departing from the scope of the invention. The invention is broadly defined and only limited by the limitations in the claims below.