GB2295205A - Vehicle jacks - Google Patents

Abstract

A jack (1) for lifting a vehicle comprises a pressurisation chamber (11), and a ram (5) which is movable in response to pressurisation of the chamber (11) for lifting the vehicle in use. The chamber (11) has a connector (12) for releasably connecting the chamber (11) to compressed air supply means (2), whereby supply of compressed air pressurises the chamber (11) to effect movement of the ram (5). <IMAGE>

Description

VEHICLE JACKS This invention relates to jacks for lifting vehicles.

Conventional car jacks. such as scissor jacks for example, are operated by cranking a handle. This can involve considerable manual effort, and many people, particularly the elderly, find the task excessively strenuous.

According to the present invention there is provided a jack for lifting a vehicle, the jack comprising a pressurisation chamber, and a ram which is movable in response to pressurisation of the chamber for lifting the vehicle in use, the chamber having a connector for releasably connecting the chamber to compressed air supply means, whereby supply of compressed air pressurises the chamber to effect movement of the ram.

With this invention, therefore, the jack is provided with a connector which enables the jack to be connected to an external compressed air supply whereby the jack can be operated with little or no manual effort. In addition to the jack, the vehicle owner need only carry in the vehicle compressed air supply means which is adapted for releasable connection to the connector of the jack. Thus, the invention encompasses apparatus for lifting a vehicle, the apparatus comprising a jack as hereinbefore described, and compressed air supply means which is adapted for releasable connection to the connector of the jack.

It is preferred that the compressed air supply means is electrically operated. For example, a battery-powered air compressor might be employed. However, it is particularly preferred that the compressed air supply means includes an electrical plug for reception in the cigar lighter socket of the vehicle to draw power from the vehicle battery. In particular, portable equipment for pumping up tyres is currently available, the equipment comprising an air compressor which is connectable to the air valve of a tyre and is provided with a plug for reception in the vehicle's cigar lighter socket to draw power for the compressor from the vehicle battery. The connector of jacks embodying the present invention is preferably adapted for use with such equipment which many vehicle owners have already purchased.

Many arrangements may be envisaged for the internal construction of the pressurisation chamber of jacks embodying the invention. For example, the chamber might include a hydraulic compartment containing water or oil which can be compressed by movement of a piston. The piston may be moved by the pressure of air pumped into a pneumatic compartment of the chamber via the said connector. In such cases, the supply of compressed air operates indirectly to move the ram by compressing the fluid in the hydraulic chamber. However, in a particularly simple arrangement, the chamber is arranged such that compressed air supplied thereto via the connector acts directly on the ram.

It is preferred that the connector includes an inlet valve to prevent escape of air from the chamber in the absence of an external force applied to the valve. Thus, once the vehicle has been jacked up, the compressed air supply means can be disconnected without release of pressure in the chamber so that the ram is maintained in its extended position. Conveniently, the inlet valve of the connector may also be adapted to function as a manually operable pressure release valve. For example, the valve may be connected to a manually operable button or lever depression of which causes the inlet valve to be opened, whereupon pressure in the chamber is released, the ram is slowly retracted, and the vehicle is lowered. Alternatively, a manually operable pressure release valve may be provided separately of the inlet valve.

An embodiment of the invention will now be described, by way of example, with reference to the single figure which is a schematic illustration of one form of vehicle lifting apparatus embodying the invention.

The apparatus illustrated in the figure comprises a jack, indicated generally at 1, and compressed air supply means indicated generally at 2. The jack 1, which is shown schematically in crosssection, comprises a base 3 having an upright cylinder 4 projecting from the upper surface thereof. A cylindrical ram 5 with a support plate 6 at one end is slidably mounted in the cylinder 4 for movement in the direction of the arrows shown in the figure. A ring seal 7 is bonded to an annular flange 8 around the lower end of the ram 5 to provide an air-tight seal with the inner surface of the cylinder 4.

The annular flange 8 is formed by the outer periphery of a disc which closes off the lower end of the cylindrical ram. An annular rim 9 at the top of the cylinder 4 bears against the outer cylindrical surface of the ram 5 to facilitate controlled movement of the ram. An air vent 10 is provided in the rim 9 for venting the interior of the cylinder 4 above the ring seal 7 to atmosphere.

The base 3 and cylinder 4 define a chamber 11 for receipt of air from the air supply means 2 via a connector 12 on the side of the chamber. The connector 12 is provided with an outer screw-thread 13, and contains an inlet valve 14 which is spring-biased into the closed position wherein passage of air through the connector 12 is prevented.

A pressure release valve 15 is also provided on an upper surface of the base 3. The release valve 15, which is also spring-biased into the closed position to prevent escape of air from the chamber 11, can be opened by depressing a button 16 to release pressure in the chamber when required.

The compressed air supply means of this embodiment comprises an air compressor 17 connected by an electrical cable 18 to an electrical plug 19 which is adapted for reception in the cigar lighter socket of a vehicle to draw power from the vehicle battery. An air pipe 20 connected to the compressor 17 terminates in a connector 21 which has an internal screw thread 22 enabling the connector 21 to be screwed onto the connector 12 of the jack. The connector 21 has an internal member 23 which allows passage of air and which forces open the inlet valve 14 of the jack when the connectors 21, 12 are screwed together.

In this embodiment, the compressed air supply means 2 is apparatus which is currently available for pumping up vehicle tyres.

When the chamber 11 of the jack 1 is not under pressure, the ram 5 is fully retracted in the cylinder 4 with the support plate 6 resting on the annular rim 9 of the cylinder. When it is desired to use the jack to lift a vehicle, the jack 1 is positioned under the vehicle, and the connector 21 of the compressed air supply apparatus 2 is screwed onto the connector 12 of the jack, thus opening the inlet valve 14.

The electrical plug 19 is then plugged into the cigar lighter socket of the vehicle, and the compressor 17 is switched on. The compressor 17 thus pumps air under pressure into the chamber 11 of the jack 1. The pressure of air acting on the lower end of the ram 5 thus causes the ram 5 to rise up in the cylinder 4 to lift the vehicle.

When the vehicle has been raised by the desired amount, the compressor 17 is switched off and, if desired, the air supply means can be detached from the connector 12 at this point, the valve 13 preventing escape of air from the chamber. When it is subsequently desired to lower the vehicle, the user simply depresses the button 16, opening the pressure release valve 15, and the air is allowed to escape slowly from the chamber. The vehicle is thus slowly lowered to the ground.

It will be seen that the apparatus described above provides a simple and efficient system for lifting a vehicle without requiring any substantial manual effort on the part of the user. The jack is simple in construction, and the arrangement of the ram 5 above the pressurisation chamber 11 leads to a compact and stable construction in which the chamber provides a base for supporting the ram. The operation is clean and safe and represents a considerable improvement over the use of conventional manually operated jacks for the reasons given above.

It will of course be appreciated that many variations and modifications may be made to the specific embodiment described above without departing from the scope of the invention. For example, jacks embodying the invention may be designed for use with other forms of compressed air supply apparatus to that specifically described above.

Claims (10)

1. A jack for lifting a vehicle, the jack comprising a pressurisation chamber. and a ram which is movable in response to pressurisation of the chamber for lifting the vehicle in use, the chamber having a connector for releasably connecting the chamber to compressed air supply means, whereby supply of compressed air pressurises the chamber to effect movement of the ram.

2. A jack as claimed in claim 1, wherein the chamber is arranged such that compressed air supplied thereto acts directly on the ram.

3. A jack as claimed in claim 1 or claim 2, wherein the connector includes an inlet valve.

4. A jack as claimed in any preceding claim, wherein the ram is mounted above the chamber.

5. A jack as claimed in any preceding claim, wherein the chamber includes a pressure release valve.

6. A jack for lifting a vehicle, the jack being substantially as hereinbefore described with reference to the accompanying drawings.

7. Apparatus for lifting a vehicle, the apparatus comprising a jack as claimed in any preceding claim, and compressed air supply means adapted for releasable connection to the connector of the jack.

8. Apparatus as claimed in claim 7, wherein the compressed air supply means is electrically operated.

9. Apparatus as claimed in claim 8, wherein the compressed air supply means includes an electrical plug for reception in the cigar lighter socket of a vehicle, to draw power from the vehicle battery.

10. Apparatus for lifting a vehicle, the apparatus being substantially as hereinbefore described with reference to the accompanying drawings.