GB2265882A

GB2265882A - A jack.

Info

Publication number: GB2265882A
Application number: GB9224515A
Authority: GB
Inventors: Gonzalez Alonso Lopez
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-04-10
Filing date: 1992-11-23
Publication date: 1993-10-13
Also published as: JPH0672699A; DE4229556A1; GB9224515D0

Abstract

A scissors-type jack for motor vehicles or the like comprises a base 2, a threaded shaft 4 rotatably journalled on the base and at least one free nut (5a, 5b) on the threaded shaft to which are pivoted struts (7a, 7b, 7c, 7d) for lifting the vehicle. The base 2 has a guide adjacent and parallel to the threaded shaft and the or each free nut has a roller 6a, 6b to co-operate with the base guide, whereby loads applied to the free nut can be transferred to the base guide. The jack may comprise an electric motor 11 operatively connected to rotate the shaft 4 and connectable to a motor vehicle power supply. The jack can have stop switches and be operated by a stop watch. One of the struts can be pivoted to the base. <IMAGE>

Description

2265882 A JACK This invention relates to jacks for motor vehicles and the

like and it particularly relates to a scissors-type jack.

Such jacks are often kept in the boot of a vehicle for use in need, for example to change a wheel.

Many vehicular jacks are awkward to position under the chassis of a vehicle to be raised and the manual lever usually provided to operate the jack is often awkward to use (in many cases fouling the bodywork of the vehicle to be jacked) and moreover is dangerous because of the close proximity to the vehicle of a person operating the jack.

In a known scissors-type jack a threaded shaft, often called a worm shaft, is provided with a free nut and pivotable jacking struts are connected to the nut and to the jack base, in which the worm shaft is rotatably journalled, the jack struts being connected to one another such that rotation of the worm shaft in one direction will cause a strut or strut ends to raise with regard to the jack base and, if coupled at their f ree end to a vehicle chassis will accordingly lift the vehicle. The jack may be arranged with the worm shaft horizontal or vertical but, in each case, the f ree nut is loaded by the weight of the vehicle. This loading can cause the nut to f ail and hence the jack to collapse.

It is an object of the present invention to overcome the aforementioned defect in worm shaft driven scissors-type jacks.

According to the present invention a scissors-type jack for motor vehicles and the like comprises a base, a threaded shaft rotatably journalled in the base, at least one jack 2 strut pivoted to a free nut on the threaded shaft, wherein the base has a guide adjacent and parallel to the threaded shaft and the or each f ree nut has a roller to co-operate with the base guide. By this means nut movement along the shaft can be guided by the base guide and, moreover, loads applied to the free nut can be transferred to the base guide.

In a preferred embodiment the jack has an electric motor operatively connected to rotate the threaded shaft and connectable to a motor vehicle power supply. The transfer of load from the free nut to the base guide enables a suitably geared electric motor to be able to operate from a motor vehicle's power supply and generate sufficient power to jack the vehicle up.

The base may be provided with stop switches to limit operation of the jack, between a lowered and a raised position, and audible and/or visible warning devices may also be connected to the stop switches to indicate operation or completion of the operation of the jack.

Thus a jack in accordance with this embodiment of the invention can be operated remotely and thus reduce risk to the operator and enable a motor vehicle to be raised by a person of insufficient strength to operate a conventional manual jack.

The above and other features of the present invention are illustrated, by way of example, in the accompanying drawings wherein:- Fig. 1 is a sectional elevation of an embodiment of a scissor jack in accordance with the present invention; Figs. la and 1b and details illustrating alternative cross-sections for the jack base; 3 Figs. lc and 1d are details illustrating alternative crown and pinion gears; Fig. 2 is a further sectional view schematically illustrating free nut rollers running in a base guide; Fig. 3 is a view similar to Fig. 1 but for an alternative embodiment of the present invention; and Fig. 4 is a view similar to Fig. 2 but for the embodiment of Fig. 3.

As shown by Figs. 1-2 a scissors-type jack 1 has an elongate base 2 of channel (Fig. la) or solid (Fig. 1b) section with upstanding end pieces 3a and 3b. A worm shaft 4 is journalled in the end pieces 3a and 3b. Two free nuts 5a and 5b engaging oppositely handed threaded portions of the shaft 4 have guide wheels 6a and 6b rotatably coupled thereto and a jack strut 7a, 7b pivoted thereto. The guide wheels 6a, and 6b run in a track 9 f ormed in a guide piece 10 attached to the base; the track 9 running parallel and adjacent to the worm shaft 4.

Jack struts 7a, 7b are pivoted together and, at their free ends, have further jack struts 7c and 7d pivoted thereto; the free ends of jack struts 7c and 7d being pivoted together and terminating in a pivoted support pad 8 that is designed to co-operate with a jacking point on a motor vehicle. An electric motor 11 is connected by a shaft 12 to the sun gear wheel of a gear system having a single planetary gear 14 (Fig. 1c) or several planetary gear wheels 14 (Fig. 1d). An output ring gear 15 of the gear system is connected to the worm shaft 4.

Stop switches 16a, 16b are provided on the base and arranged to be contacted by the nut rollers 6 when the jack is fully extended (switch 16a) and fully lowered (Fig. 16b).

A Acoustic and/or electric warning devices could also be connected to stop switches 16a to indicate that the jack is in use or when the jack has completed operation to extension or retraction. For safety, the jack may be remotely operated via a remote control panel.

The end 17a of the worm shaft 4 f rox motor 11 and gear 15 is provided with a nut 22 so that, in the event of failure of the motor 11, the nut can be turned to raise or lower the jack manually.

The struts 7a, b, c, d or whole of the scissor jack may be protected by a rubber or like gaiter (not shown).

In the alternative embodiment shown by Figs. 3 and 4 like parts have been given like references and the essential difference between the two jacks is that, in this embodiment, there is only one free nut 5b, engaging a uniformly threaded shaft 4 and having rollers 6b running in tracks 9, in this case f ormed directly in the base 2. A jack strut 17 is pivoted to free nut 5b. A further, longer jack strut 19 is pivoted at one end 20 to base upright 3a and jack strut 17 is pivoted to the mid-length 18 of jack strut 19; the free end of which terminates in a chassis or ground contacting member or roller 21. Operation of this embodiment using the motor 11 connected to the worm shaf t 4 via the gear system and controlled by the stop switches 16a, 16b is similar to the embodiment of Figs. 1 and 2.

Claims

CLAIMS:

1. A scissors-type jack for motor vehicles or the like and comprising a base, a threaded shaft rotatably journalled on the base and at least one strut pivoted to a free nut on the threaded shaft, wherein the base has a guide adjacent and parallel to the threaded shaft and the or each free nut has a roller to co-operate with the base guide.

2. A jack as claimed in claim 1, wherein the roller or rollers co-operate with a guide track on the base.

3. A jack as claimed in claim 2 and comprising a pair of struts, each pivotted to a free nut on the threaded shaft.

4. A jack as claimed in claim 2 and comprising a pair of struts, one pivotted to a free nut on the threaded shaft and the other pivotted to the base.

5. A jack as claimed in any of claims 1 to 4 and having a electric motor operatively connected to rotate the threaded shaft and connectable to a motor vehicle power supply.

6. A jack as claimed in claim 5, wherein the base is provided with stop switches arranged to be operated by a free nut; to thereby control the motor and hence operation of the jack.

7. A jack as claimed in claim 6 and having acoustic and/or visible warning devices connected to activated by operation of a stop swatch.

8. A jack as claimed in any preceding claim wherein the or each strut is protected by a flexible gaiter.

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9. A jack as claimed in any preceding claim operable remotely via a remote control panel.

10. A scissors-type jack for motor vehicles or the like, substantially as described with reference to or as shown in the drawings.

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