FIELD OF THE INVENTION

The present invention relates to vehicle jacks and more particularly it pertains to a single-wheel hydraulic jack having a wheel tray that is inclinable in a first direction for facilitating the rolling of a wheel therein, and in a seconddirection for preventing a wheel from rolling off the jack during the lifting of a vehicle with the jack.

BACKGROUND OF THE INVENTION

Vehicle jacks are used in garages and body repair shops for examples, for lifting one or more wheels of a vehicle off the ground for carrying out repair or maintenance work on the vehicle. Vehicle jacks are sometime used by apprentices andinadvertent vehicle owners having more or less appreciation for the risks associated with the lifting of a vehicle and working under it. Conventional bumper jacks, axle jacks and scissors-type chassis jacks for examples are known to be unstable incertain circumstances and are generally not recommended for use without additional safety blocking. In that regard, clear written safety instructions are normally provided with the purchase of every vehicle jack. However, because of the inexperience ofsome users of vehicle jacks, and for other various reasons, proper vehicle lifting instructions are not always followed and users of vehicle jacks continue to be exposed to serious accidents.

In regard to improving the safety of vehicle jacks, a number of single-wheel jacks have been developed in the past. Some of these single-wheel jacks have a wheel tray for receiving a vehicle wheel and a broad base to prevent tilting of the jackwhen used on soft or uneven ground for example. Three models of single-wheel jacks of the prior art are described and illustrated in the following documents for reference purposes:

U.S. Pat. No. 3,292,902 issued on Dec. 20, 1966 to M. F. Lynch. The portable tire lift illustrated therein has a broad base, a lifting plate, a wheel tray mounted to the lifting plate and a scissors-type lifting mechanism connected to thebroad base and to the lifting plate. A support post is mounted to the base and is engaged into a portion of the lifting plate. The post has vertically spaced-apart ridges for supporting the lifting plate and for preventing accidental collapsing of thelifting plate.

U.S. Pat. No. 3,784,161 issued on Jan. 8, 1974 to R. L. Frese. The wheel removal safety device illustrated therein is used for assisting in positioning a flat tire wheel at a certain height such that an axle jack or a bumper jack may beinstalled for removing and replacing the wheel. The device has a tilting plate forming an inclined surface on which the wheel is driven. The plate has a fulcrum at its centre point and is adapted to tilt and form an elevated horizontal surface when awheel is driven thereon and moves pass the fulcrum. A conventional jack is then easily introduced under the elevated axle or bumper.

U.S. Pat. No. 5,503,368 issued on Apr. 2, 1996 to Manuel Torres. This patent describes a scissors-type wheel lift having broad base, a wheel tray and a scissors-type lifting mechanism connected to the wheel tray and to the broad base, forlifting the wheel tray. The wheel lift is used in combination with a ramp having a height corresponding to the height of the wheel tray when the wheel tray is in a collapsed mode. In use, a wheel is driven over the ramp and into a wheel tray. A handcrank and a screw are used to operate the scissors-type lifting mechanism.

It has been found that a common problem with the lifting of a vehicle with a jack is that a partial raising of a vehicle, on one corner or on one end of the vehicle, causes the whole vehicle to be pulled toward the jack. Therefore, when thewheel being lifted is not properly retained inside the wheel tray of a jack, or when one of the supporting wheels is chocked against the jack, the wheel being lifted tends to roll out of the wheel tray, thereby causing a hazardous condition.

Another problem with scissors-type lifting mechanisms of single-wheel jacks of the prior art is that the mechanism has a substantial vertical thickness. Modern compact vehicle have relatively small diameter wheels, of 14 and 15 inches forexamples. These wheels are often too small to afford a smooth rolling over the scissors-type lifting mechanism and into the wheel tray of these vehicle jacks.

It is believed that these problems basically, have contributed to cause significant obstacles to the commercial success of the wheel-tray-type jacks of the prior art. It is further believed that there continues to be a need for a bettersingle-wheel jack capable of being used easily and safely by the experienced tradesmen as well as by the hobby-time auto-mechanics.

SUMMARY OF THE INVENTION

In the present invention, however, there is provided a single-wheel jack that has a wheel tray that is inclinable in two directions, to facilitate the entry of a wheel therein when the jack is in a collapsed mode, and to positively retain avehicle wheel when the jack is in a raised mode. The single-wheel jack of the present invention further has a latching mechanism to prevent unintentional lowering of the wheel tray.

Broadly, in accordance with a first feature of the present invention, there is provided a jack for raising a wheel of a vehicle and comprising a horizontal base having spaced-apart front end and entry end, spaced-apart side members extendingbetween the front end and the entry end and longitudinal and transversal dimensions. A scissors-like lifting mechanism is connected to the horizontal base and has an upper end movable between a raised position at a distance above the horizontal base anda collapsed position against the horizontal base. A force-applying actuator is connected to the horizontal base and to the scissors-like lifting mechanism for actuating the scissors-like lifting mechanism. A wheel tray is connected to the upper end ofthe scissors-like lifting mechanism for up and down movements thereof between the raised position and the collapsed position. The wheel tray has spaced-apart front portion and entry portion, a bottom surface and a bumper on the front portion.

There is also provided a crossbar mounted in the scissors-like lifting mechanism for engaging with the wheel tray and for causing the entry portion of the wheel tray to lean down relative to the front portion when the upper end of thescissors-like lifting mechanism is in the collapsed position.

The scissors-like lifting mechanism has connections with the front and entry portions of the wheel tray and the connections with the front portion are differing in height and engagement sequence with the connections with the entry portion forcausing the front portion of the wheel tray to lean down relative to the entry portion when the upper end of the scissors-like lifting mechanism is in the raised position.

The principal advantages of the jack of the present invention are that the wheel tray of the jack is inclinable to lean down toward the entry end of the horizontal base for facilitating a rolling of a vehicle wheel therein when the scissors-likelifting mechanism is in a collapsed position, and the wheel tray is inclinable to lean down toward the front end of the horizontal base, when the scissors-like lifting mechanism is in a raised position, for urging a vehicle wheel against the bumper ofthe wheel tray and for preventing the vehicle wheel from rolling out of the wheel tray.

According to another feature of the present invention, the scissors-like lifting mechanism has a pair of spaced-apart drive members and a pair of spaced-apart driven members joined at their midpoints by a pair of spaced-apart pivots defining atransversal articulation axis of the scissors-like lifting mechanism. The scissors-like lifting mechanism is actuated by an hydraulic cylinder connected to the base and to the spaced-apart drive members. When the scissors-like lifting mechanism is in acollapsed position, a longitudinal axis of the hydraulic cylinder is offset from the transversal articulation axis by a distance of at least 1/8 inch to 3/16 inch. This offset distance has been found to be advantageous for providing a substantial momentof force by the hydraulic cylinder on the scissors-like lifting mechanism for initiating a lift with ease.

In accordance with another feature of the present invention, there is provided a latching mechanism comprising a latch block affixed to the

horizontal base and a loop member connected to one of the drive members for engagement with the latch block, when the scissors-like lifting mechanism is in the raised position. The scissors-like lifting mechanism is thereby lockable in theraised position for preventing accidental or unintentional lowering thereof.

In yet another feature of the present invention, the latching mechanism comprises a pair of wedge-like latch blocks respectively connected to one of the side members of the horizontal base and a pair of loop-shaped hook members respectivelyconnected to one of the lower ends of the drive members. The loop-shaped hook members have inside dimensions for engagement with the wedge-like latch blocks as soon as the scissors-like lifting mechanism reaches a raised position.

The loop-shaped hook members are joined to one another by a round bar. A pair of cleft tabs are mounted on an actuator rod pivotally connected to the side members of the horizontal hollow base and extending parallel to and at proximity of theround bar when the hook members are engaged over the latch blocks, for engagement of the cleft tabs with the round bar. Each of these cleft tabs has a fork-like end for engagement thereof with the round bar and for selectively lifting the round bar andthe loop-shaped hook members over the wedge-like anchor blocks. The actuator rod further has a handle connected thereto and disposed outside the horizontal hollow base. The scissors-like lifting mechanism is thereby releasable from a latch condition byactuating the handle on the actuator rod.

Still other features of the invention are that it is susceptible of a low cost of manufacture with regard to materials, equipment and labour, and which accordingly is then susceptible of low price of sale to the industry, thereby making suchsingle-wheel jack economically available to the public.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the present invention is illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:

FIG. 1 is an entry end, right side and top perspective view of the single-wheel hydraulic jack according to the preferred embodiment of the present invention, shown with the wheel tray in a raised position;

FIG. 2 is a top plan view of the single-wheel hydraulic jack shown with a partial view of the handle member usable for operating the hydraulic cylinder of the jack;

FIG. 3 is a partial transversal cross-section view of the wheel tray of the single-wheel hydraulic jack, as seen along line 3--3 in FIG. 2, but with the wheel tray in a raised position;

FIG. 4 is a partial longitudinal cross-section view of the single-wheel hydraulic jack as seen along line 4--4 in FIG. 2, but with the scissors-like lifting mechanism in a collapsed position;

FIG. 5 is a side view of the single-wheel hydraulic jack, shown with the scissors-like lifting mechanism in the collapsed position, with a partial view of a wheel being driven in the wheel tray;

FIG. 6 is a side view of the single-wheel hydraulic jack shown with the scissors-like lifting mechanism in the raised position and a partial view of a wheel being supported in the wheel tray;

FIG. 7 illustrates a partial top view of the horizontal base of the single-wheel hydraulic jack according to the preferred embodiment;

FIG. 8 is a first side view of the locking mechanism mounted inside the horizontal base of the single-wheel hydraulic jack and shown in a locked position;

FIG. 9 is a second side view of the locking mechanism shown with the cleft tabs in an engaged and active mode;

FIG. 10 is a third side view of the locking mechanism shown with the cleft tabs in an unlatching mode;

FIG. 11 is an entry end and right side perspective view of a wheel chock usable with the single-wheel hydraulic jack according to the preferred embodiment;

FIG. 12 is a partial cross-section of the hydraulic cylinder base showing a partial view of a flow control valve usable to regulate the lowering speed of the single-wheel hydraulic jack; and

FIG. 13 is a front and right side partial perspective view of a socket and a handle used to operate the hydraulic cylinder on the single-wheel hydraulic jack according to the preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERREDEMBODIMENT

While this invention is susceptible of embodiments in many various forms, there is shown in the drawings and will be described in details herein a specific embodiment, with the understanding that the present disclosure is to be considered as anexample of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

The preferred embodiment of the present invention is a single-wheel hydraulic jack 20 usable for lifting a single wheel of a vehicle. The utility of this jack is well known to auto-mechanics, to body shop personnel and to all individuals whoperform maintenance work on wheeled vehicles. This single-wheel hydraulic jack 20 is particularly advantageous for its low profile when it is in a collapsed mode, for its inclined wheel tray when fully raised, for its locking mechanism, and for severalother features that are described herein below. The single-wheel hydraulic jack 20 according to the preferred embodiment is also referred to herein as the vehicle jack.

The vehicle jack 20, several features of which are illustrated in FIGS. 1-6, comprises broadly, an horizontal hollow base 22, a scissors-like lifting mechanism 24 mounted to the base, an hydraulic cylinder 26 connected to the base and to thescissors-like lifting mechanism for actuating the scissors-like lifting mechanism 24, and a wheel tray 28 mounted to the scissors-like lifting mechanism for receiving a wheel 30 to be raised.

The horizontal hollow base 22 is preferably rectangular in shape and made of angle iron having a thickness `A` from the ground of about 11/2 inches (38 mm) as shown in FIG. 4. The horizontal rectangular base 22 has a front end and an entry end,a longer side defining a longitudinal dimension and a shorter side defining a transversal dimension. The front end is the portion where the hydraulic cylinder 26 is mounted, and the entry end is the portion upon which a vehicle wheel rolls over to enterthe wheel tray 28.

A pair of fixed devises 32 are affixed to the front end of the base 22 for rigidly supporting the pivot end of the hydraulic cylinder 26. There is also provided a pair of gusset members 34 affixed diagonally across each corner of the front endof the base for reinforcing that end of the base 22.

A first handle 36 is affixed to the front end of the base 22 for handling the vehicle jack 20 about a garage or under a vehicle. A second handle 38 is optionally affixed to the entry end of the base 22 to further facilitate the handling of thevehicle jack 20. This optional handle 38 is preferably a retractable one such that the vehicle jack 20 according to the preferred embodiment can be shipped or stowed in a form which is as compact as possible.

The scissors-like lifting mechanism 24 comprises a pair of drive members 40 set inside a pair of driven members 42 and connected to the driven members 42 by means of a pair of pivots 44 defining a first transversal articulation axis thereofpassing through the midpoint of each of the members 40 and 42.

The drive members 40 have a respective first upper-driven end pivotally connected to the entry portion of the wheel tray 28 at pivots 46 on the wheel tray, and a respective lower drive end 48 having a lower roller 50 affixed thereto. The drivemembers 40 are mounted and extend astride the bottom surface of the wheel tray 28.

Each lower roller 50 is adapted to roll inside the angle iron of the horizontal base 22. Each lower roller 50 is preferably the type having a threaded stem extending along an axis thereof and being known in the industry as a track runnerbearing.

There is also provided, and mounted across the drive members 40, a crossbar 60 which is visible in the perspective view in FIG. 1 and in the cross section view in FIG. 4. The crossbar 60 is connected to both drive members 40, near the drivenends of the drive members 40 and has a pair of driven devises 62 connected thereto for pivotally receiving the rod end of the hydraulic cylinder 26 and for transmitting the force of the hydraulic cylinder 26 to the drive members 40.

The driven members 42 have a respective lower reactive end pivotally connected to the entry end of the base 22 at pivots 64. The upper driven end of each driven members 42 has an upper roller 66 which is adapted to roll inside a channel-likerail member 68 formed in the wheel tray 28. Hence, when the drive members 40 are pushed by the hydraulic cylinder 26, the drive and driven members 40, 42 are pivoted about the transversal articulation axis 44 for lifting the wheel tray 28 in a mannerwhich is common to scissors-type lifting mechanisms.

The longitudinal axis 70 of the hydraulic cylinder 26 is preferably set at an angle `B` of one or few degrees down from a horizontal line 72 such that the force of the hydraulic cylinder 26 causes the lower rollers 50 to remain in contact withthe angle iron of the base 22. The alignment of the axis 70 also contributes to providing a push-force moment about the transversal articulation axis 44 for initiating a lifting action. For this purpose, a minimum distance `C` of about 1/8 to 3/16 inch(3-5 mm) is preferably maintained between the longitudinal axis 70 of the hydraulic cylinder 26 and the transversal articulation axis 44.

The wheel tray 28 is preferably manufactured with pressed metal sheet. A channel-like rail member 68 is preferably formed on each side of the wheel tray 28 for laterally enclosing a bottom surface of the wheel tray. The wheel tray 28 preferablyhas reinforcing corrugations 74 across its bottom surface for reinforcing the bottom surface. The wheel tray 28 further has a front bumper 76 across its front end.

Referring now particularly to FIGS. 4-6, there are illustrated therein some important features of the vehicle jack 20 according to the preferred embodiment. A first important feature is that when the vehicle jack 20 is fully collapsed, thebottom portion of the wheel tray 28 comes in contact with the crossbar 60 and is raised by the crossbar 60 as illustrated in FIG. 4. The crossbar 60 causes the wheel tray 28 to tilt about the pivots 46 an angle `D` of one or few degrees from ahorizontal plane, such that the front portion of the wheel tray remains above the hydraulic cylinder 26 and above the driven devises 62, and such that the entry portion of the wheel tray 28 is able to at least partly retract into the base 22. Thisfeature is particularly appreciable for easily driving a wheel 30 into the wheel tray 28 without requiring a ramp or similar inclined structure at the entry end of the wheel tray 28, as illustrated in FIG. 5.

The tilting of the tray 28 as just described causes the front portion of the tray to be raised above the upper rollers 66 on the driven members 42 by a distance `E` as also illustrated in FIG. 5. Therefore, when the hydraulic cylinder 26 isextended from a retracted position, the entry portion of the wheel tray 28 starts to rise first, and continues to be raised until the upper rollers 66 are up into the channel-like rail members 68, and in contact with the inside portion of the railmembers 68.

The height of the crossbar 60 relative to the drive members 40 when these drive members are in the collapsed mode, the engagement sequence between the driven ends of the drive and driven members and the wheel tray, and the associated distance `E`are preferably selected such that when the upper rollers 66 are in contact with the channel rail members 68, the wheel tray 28 is lightly inclined downward forwardly.

The thickness of the crossbar 60, the location of the pivots 46, the distance `E` and the size of the upper rollers 66 are selected such that when the wheel tray 28 is in a raising mode and in a raised position, it is preferably inclinedforwardly an angle `F` of one or few degrees below an horizontal line 78, to urge the wheel 30 being raised against the front bumper 76.

The preferred inclination `F` is a difference of about 1/2 inch (13 mm) between the height `G` of the front portion, the front portion being lower, and the height `H` of the entry portion. This feature is advantageous for preventing the wheel 30from rolling off the vehicle jack 20 when the vehicle jack is in use.

For additional safety, although this is optional, a wheel chock 80 having an anchor pin 82 thereon as illustrated in FIG. 11, may be installed in the wheel tray 28 as illustrated in FIG. 6, with the anchor pin 82 inserted into one of severalholes 84 provided for this purpose in the bottom surface of the wheel tray 28.

Referring now to FIGS. 7-10, there is illustrated therein another important feature of the vehicle jack 20 according to the preferred embodiment. The vehicle jack 20 has a locking mechanism 90 for locking the scissors-like lifting mechanism 24in a raised position. The locking mechanism 90 comprises a pair of elongated loop-shaped hook bars 92 respectively pivotally connected to the lower end 48 of a drive member 40. Each loop-shaped hook bar 92 is adapted to engage onto a wedge-like anchorblock 94 affixed to the lower portion of the side member 96 of the horizontal base 22, when the drive members 40 reaches an uppermost position. Both loop-shaped hook bars 92 are connected to each other by a transversal round bar 98 such that they aremovable together.

There is also provided, a pair of cleft tabs 100 rigidly mounted on an actuator rod 102 extending across the base 22. The actuator rod 102 extends along the transversal round bar 98 when the scissors-like lifting mechanism reaches a raisedposition. The actuator rod 102 extends through the angle iron of the base 22, and has one or two handle-like bent portions 104 extending outside the base 22.

When the scissors-like lifting mechanism 24 is actuated to raise the wheel tray 28, the loop-shaped hook bars 92 slide over the inclined surfaces 106 of both anchor blocks 94, and drop down at the entry end of the anchor blocks 94 to engage withthe anchor blocks 94 as shown in FIG. 8, and to prevent any unintentional lowering of the jack 20. During this motion, the transversal round bar 98 slides over the cleft tabs 100, and rests above the cleft tabs 100 as illustrated in FIG. 8.

The releasing of the locking mechanism 90 is effected by turning the bent portion 104 of the actuator rod 102, causing the cleft tabs 100 to lift the transversal round bar 98 and to cause the loop-shaped hook bars 92 to disengage from the anchorblocks 94. The turning of the cleft tabs 100 in a counterclockwise direction as indicated by arrow 108 in FIG. 9 also causes the transversal round bar 98 to engage into a hollow 110 in each cleft tab 100. Each hollow 110 is defined by a forward leg 112and an entry side leg 114. The forward leg 112 is longer than an entry side leg 114 such that a turning of the tabs 100 in the counterclockwise direction 108 is partly limited by the engagement of the forward legs 112 against the transversal round bar98, as illustrated in FIG. 9. The rotation of the cleft tabs 100 in a counterclockwise direction 108 is also limited by a stopper pin 116 protruding from the side of the base 22 and acting against the handle-like bent portion 104. The stopper pin 116is illustrated in FIGS. 1 and 5-7.

During the lowering of the vehicle jack 20 according to the preferred embodiment, the cleft tabs 100 retain the transversal round bar 98 and both loop-shaped hook bars 92 in a raised position above the anchor blocks 94. The lowering of the wheeltray 24 causes the cleft tabs 100 to rotate in a clockwise direction as indicated by arrow 118 and to release the transversal round bar 98 when the loop-shaped hook bars 92 are in a position to slide down over the inclined portion 106 of the anchorblocks 94, as illustrated in FIG. 10.

The lowering of the vehicle jack 20 according to the preferred embodiment is preferably effected in a smooth and controlled condition to avoid any sudden drop of the vehicle's wheel 30. Therefore, when a common hydraulic cylinder 26 is used tooperate the scissors-like lifting mechanism, the

release valve in this cylinder is preferably equipped with a flow regulator such as an elongated needle-type screw 120 in the oil return path of the valve, such as illustrated in FIG. 12, or any other flow control devices known in the industry.

Referring now to FIGS. 2 and 13, the pump-handle bar 130 used to actuate the hydraulic cylinder 26 is preferably bent sideway an angle `J` of between about 5 degrees and about 45 degrees. This feature is preferred for preventing a rubbing of thehandle bar 130 against a painted surface of a bumper or a fender of a vehicle for example when the vehicle jack 20 is used to raise a wheel of a vehicle.

It will be appreciated, however, that the vehicle jack 20 may be used under a driver or a passenger side of a vehicle and therefore, the handle bar 130 according to the preferred embodiment is reversible for use on either sides of a vehicle. Forthis purpose, the handle bar 130 has a pair of tabs 132, 134 extending in opposite directions from each other and from the socket-engaging end of the handle, and at right angle with a plane defined by the angle `J`. Each tab is mountable into a slot 136formed under the pump socket 138 of the hydraulic cylinder 26. The engagement of either tabs 132, 134 into the slot 136 prevents a rotation of the bar 130 when pumping the hydraulic jack 26 of the vehicle jack 20. The slot 136 is defined by a pair ofspaced-apart and parallel plates 140, affixed to an underside of the pump socket 138. Therefore, the handle bar 130 is usable for examples, on a driver side of a vehicle with the tab 134 engaged into the slot 136, or on a passenger side of a vehiclewith the tab 132 engaged into the slot 136.

Each of tabs 132, 134 preferably has a rounded notch 142 therein for optional engagement with the first handle 36 or with any part of the vehicle jack, for conveniently moving the vehicle jack 20 on a shop floor or from under a vehicle.

As to further manner of usage, further structural details and manufacturing of the vehicle jack according to the present invention, the same should be apparent from the above description and accompanying drawings, and accordingly, furtherdiscussion relative to these aspects would be considered repetitious and is not provided.

It will also be appreciated that while the above description provides a full and complete disclosure of the preferred embodiment of this invention, various modifications, alternate constructions and equivalents may be employed and various usesmay be devised without departing from the true spirit and scope of the invention. Such changes might involve alternate components, structural arrangements, construction features or the like. Therefore, the above description and the illustrations shouldnot be construed as limiting the scope of the invention which is defined by the appended claims.

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