IMPROVEMENTS TO CAR JACK

Abstract: A jack for a vehicle comprises a transverse base member (1) supported on a pair of wheels (2) and has a handle (3) extending perpendicularly to the base member (1). A mast (6) extends perpendicularly to the base member (1) and the handle (3) and includes a lower part (6a) and an upper part (6b) telescopically connected and maintained in a selected position relative to one another by a pin (7) extending through cooperating holes (8) in the upper and lower mast parts (6a) and (6b). A U-shaped engagement head (9) is pivotably connected to the upper end of the upper most part (6b) and is adapted to receive the axle or other suitable portion of a vehicle to be lifted. To lift a vehicle the handle (3) is raised and the U-shaped head (9) is positioned under a suitable portion of the vehicle, after the mast length has been adjusted to a suitable length. The handle (3) is then depressed to lift the vehicle until the handle (3) touches the ground with the head (9) disposed slightly to the handle (3) side of the axle of wheels (2). During lifting the U-shaped head (9) remains with its base substantially parallel to the ground, thereby minimizing the risk of the vehicle sliding off the jack and at the same time minimizing relative motion of the vehicle and jack at the point of contact, thereby avoiding damage to the vehicle.

Description: IMPROVEMENTS TO CAR JACK The present invention relates to car jacks, and in particular the invention provides an improved engagement head for a car jack whereby the risk of damage to the vehicle being jacked is reduced. In a car jack of the type having a pair of wheels mounted one on either end of a base member, an elongate handle member extending substantially perpendicularly to said base member and a strut member extending substantially perpendicularly to a plane defined by said base member and said handle member, the distal end of said strut member having a head portion including a vehicle supporting surface, the head portion being disposed on the handle side of a vertical plane through the centre of said wheels when the wheels and handle are resting on the ground, the present invention comprises the improvement wherein the head portion is pivotably connected to said strut member, such that the vehicle supporting surface is pivotable between a first position substantially perpendicular to said strut member and a second position inclined towards the handle. In a preferred form of the invention the head portion is pivotable through an angle of 45°. An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is an elevation view of a jack incorporating the present invention; Fig. 2 is a plan view of the jack of Fig. 1; Fig. 3 is an end elevation view of the jack of Fig. 1; Fig. 4 is a detailed view of the head of the jack illustrated in Fig. 3 with the head tilted; and Fig. 5 is a detailed view of the upper most of Fig. 1 with the head of the jack tilted. Fig. 6 is an elevation view of a prior art jack in use; and Fig. 7 is an elevation view of a jack accoring to the present invention in use under circumstances similar to those of Fig. 6. The type of jack to which the improvement of the present invention is applied has a base member 1 to which a pair of wheels 2 are attached one at either end thereof. An elongate handle 3 extends perpendicularly from the base member 1 and has a slight bend 4 enabling the distal end of the handle to be spaced from the ground when the wheels 2 and the bend 4 in the handle are resting on the ground. A mast 6 extends substantailly perpendicularly from the handle 3 and comprises two members 6a and 6b which telescope together to provide a height adjustment, the length of the mast 6 being fixed by inserting a pin 7 through one of a series of holes 8, the upper end of. the mast having a U-shaped engagement head 9 provided for engaging with the underside of the vehicle to be jacked. The pin 7 is connected to the upper mast 6b by a chain 13 the length of which is such that the pin can be inserted through the lowest of the holes 8 of the uppermost member 6b but is not long enough to allow the uppermost section 6b to rest on top of the pin without the pin engaging one of the holes 8 of the uppermost member, thereby preventing unsafe use of the jack. The chain 13 also prevents loss of the pin 7. In use, the height of the strut 6 is adjusted to the height to which the vehicle is to be lifted, and the handle 3 is raised until the engaging head 9 may be placed under the jacking point on the vehicle chassis to be lifted. With the head 9 engaging the underside of the vehicle, the handle 3 is then pushed back to the ground thereby pivoting the strut 6 into a substantially vertical position under the point on the chassis with which the head 9 is engaged. Once the handle is again resting on the ground the head 9 will have travelled past a point directly above the centre of the wheels 2 such that the weight of the vehicle on the head 9 will tend to hold the handle 3 against the ground. In prior art jacks of the type described herein, the head 9 was fixed to the strut 6 and under certain circumstances would cause damage to the vehicle during the lifting and lowering operations, due to the relative movement of the head and the point on the chassis with which it is engaged. In some cases, the vehicle can also roll off of the jack during these lifting and lowering operations. The present invention provides an improvement to the jack of the type described, wherein the engaging head 9 is pivotably attached to the strut 6 by a pin 10 and the top of the strut is arranged to provide a pair of stops 11 which limit the angle through which the head 9 can pivot. With this arrangement, the upper surface 12 of the head 9 may be kept horizontal, and stationary with respect to the point being lifted, while the strut 6 is pivoting under the head 9 to lift the vehicle. The risk of damage to the vehicle will therefore be removed by eliminating the relative movement of the upper surface 12 of the head with respect to the point at which the vehicle- is being lifted. Preferably the angle through which the head 9 should be allowed to pivot by stops 11 is equal to the angle through which the jack travels during the lifting operation, however, this angle will change depending on the height to which the vehicle is to be lifted, and therefore, an angle of 45° has been selected as the most suitable for normal usage. At one extreme of the pivotal range of the head, the upper surface 12 of the head 9 will be perpendicular to the longitudinal axis of the mast 6 as shown in dashed line in the detail of Figure 1, while at the other extreme the surface 12 will be tilted at an angle of 45° towards the handle 3 as shown in solid line in the detail of Figure 1. Preferably, the holes 8 through which the pin 7 is inserted to maintain the mast 6 in an extended position are offset from the centre line of the mast in order that the upper mast 6b cannot be reversed with respect to the lower mast 6a. Referring now to Fig. 6, a prior art jack having a fixed head 18 is illustrated in position under the reinforced jacking point 16 of a vehicle. It will be seen that for a given lift height, the prior art jack is severely restricted with regard to the minimum vehicle height for which it is suitable due to the inability of the head 18 to safely engage a suitable jacking point underneath a vehicle when the vehicle is too low to the ground. By comparision, for the same lift height, the jack according to the present invention, illustrated in Fig. 7, can safely engage the reinforced jacking point of a low vehicle, due to the pivotal nature of its head 9. This feature of jacks made in accordance with the present invention is particularly important when the jack is used on vehicles which are lower to the ground than usual, such as when a vehicle has a flat tire. It will be recognised by persons skilled in the art that numerous variations and modifications may be made to the invention as hereinbefore described without departing from the spirit or scope of the invention as broadly described.

Claims: CLAIMS : - 1. In a car jack of the type having a pair of wheels mounted one on either end of a base member, an elongate handle member extending substantially perpendicularly to said base member and a mast extending substantially perpendicularly to a plane defined by said base member and said handle member, the distal end of said mast having a head portion including a vehicle supporting surface, the head portion being disposed on the handle side of a vertical plane through the centre of said wheels when the wheels and handle are resting on the ground, the improvement wherein the head portion is pivotably connected to said mast, such that the vehicle supporting surface is pivotable between a first position substantially perpendicular to said mast and a second position inclined towards the handle. 2. The improved vehicle jack of claim 1, wherein the vehicle supporting surface is pivotable through an angle substantially equal to an angle through which the jack is moved when jacking a vehicle. 3. The improved vehicle jack of claim 1, wherein the vehicle supporting surface is pivotable through an angle of substantially 45°. 4. The improved vehicle jack according to Claim 1 wherein the mast comprises a lower mast member connected to and extending from the base member and an upper mast member telescopically extending from the lower mast member, the upper and lower mast members being provided with locking means to releasably lock them against relative movement. 5. The improved vehicle jack according to claim 4 wherein the upper and lower mast members are tubular and means are provided to maintain correct orientation of the upper mast member with respect to the lower mast member. 6. The improved vehicle jack of claim 5 wherein the upper and lower mast members are lockable by means of a pin locatable in holes extending through each of the mast members. 7. The improved vehicle jack of claim 6 wherein the holes are located off centre in each of the mast members to ensure correct orientation of the upper member with respect to the lower member when the jack is in use. 8. The improved vehicle jack of claim 6, wherein the pin is connected to the uppermost member by a chain, the length of which is selected such that the uppermost member cannot be supported on top of the pin without the pin being secured through one of the holes of the uppermost member.

Inventors: KELFKENS BRIAN WALTER, KELFKENS, BRIAN, WALTER
Applicants: QUICK JACK PTY LIMITED, QUICK JACK PTY. LIMITED
Application year: 1985
Main classification: B66F5
IPC codes: B66F15