WO1993000287A1

WO1993000287A1 - Pantograph jack apparatus

Info

Publication number: WO1993000287A1
Application number: PCT/NO1992/000114
Authority: WO
Inventors: Edvin List Clausen
Original assignee: Norsk Hydro A.S
Priority date: 1991-06-28
Filing date: 1992-06-26
Publication date: 1993-01-07
Also published as: NO173928B; NO912551D0; NO912551L; NO173928C

Abstract

A pantograph jack apparatus comprises supporting arms (3, 4, 6, 7) extruded of light metal with all details including integrated complementary shaped gear portions for their mutual engagement.

Description

Pantograph jack apparatus

The present invention relates to a pantograph or scissors type of jack apparatus for elevating the body of a vehicle and more particularly to a novel pantograph jack of light weight which can be assembled in a simple manner.

A conventional pantograph jack apparatus comprises first and second upper arms pivotally connected to a supporting plate engageable with the vehicle by means of pins or bolts and first and second lower arms pivotally connected to a base plate by means of pins or bolts. The first upper arm and the first lower arm are further pivotally connected to a threaded connecting nut which is threaded on the threaded portion of a horizontally extending shaft member. The second upper arm and the second lower arm are pivotally connected to a connecting bearing rotatably mounted on the non-threaded portion of the shaft member. The connecting bearing is axially movable on the shaft member between two stop positions by means of an operating member connected to the non-threaded end of the shaft member. When the operating member is rotated by means of e.g. a crank handle, the shaft member rotates causing the connecting nut to move either toward or away from the connecting bearing so that the supporting plate is either raised or lowered in relation to the base plate by the known pantograph action principle. When stored in the motor vehicle, the upper arms are substantially parallel to the lower arms due to the rotating of the operating member and shaft member producing a maximum separation between the connecting bearing and the connecting nut, while a minimum separation between the supporting and base plate is achieved.

Presently, most of the components and members like supporting arms and plates are made from sheet metal (steel) as stamped parts. There is an increasing demand for low weight ^* motor vehicles caused by different national laws and rules requiring a substantial reduction of the fuel consumption. As a result of this a considerable switch from steel to light metals, especially aluminium and its alloys applied as construction material for vehicle bodies, engine parts, wheels and tubing has been experi¬ enced during the last years. Furthermore, even auxiliary equipment such as spare wheels and vehicle jacks have been scrutinized with regard to possible weight saving. Several attempts have already been made to replace some of the steel parts in the commercial vehicle jacks with aluminium alloys. However, a direct substitution of steel members as a replica in aluminium is not possible due to the differences in material characteristics. Consequently, it has been necessary to strengthen such members, e.g. the aluminium arms, by means of reinforcing attached pieces. Such a solution has several disadvantages. The actually achieved weight reduction is only a fragment of the potential one. Assembling of jacks is complicated and manufacturing costs increased by the necessity to apply and align a larger number of components.

It is therefore an object of the present invention to provide a novel pantograph jack having light weight combined with adequate strength and performance exhibiting no increase in the number of the construction parts.

Another object of the present invention is to provide a panto¬ graph jack which can be simply and inexpensively manufactured. These and other objects, features and advantages of the invention will become readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings, Figs. 1-3, where

Fig. 1 is a schematical side plan view of the pantograph jack apparatus in lowered position for storage,

Fig. 2 is a sectional side plan view of the pantograph jack in its raised position for enganging with a vehicle body, and

Fig. 3 is a sectional view taken along lines I-I of Fig. 2.

Fig. 1 shows the pantograph jack of the present invention comprising a base plate 1 positioned on the ground and a supporting plate 2 engageable with the vehicle body (not shown in the Figure) . The first 3 and second 4 upper arms are pivotally connected to the supporting plate 2 by means of bolts 5. The first 6 and second 7 lower arms are pivotally connected to the base plate 1 by means of bolts 5* . The first upper arm 3 and the first lower arm 6 are further pivotally connected to a threaded connecting nut 8 and the second upper arm 4 and the second lower arm 7 are pivotally connected to the corresponding connecting nut 8• . Both connecting nuts are axially movable along a threaded horizontally extending shaft member 9.

In accordance with the present invention all arms 3,4,6 and 7 are provided as ready to use arms with all integrated details and functions in one single shape extruded in light metal, preferen¬ tially Al-alloy. Thus, the extruded arms include complementary and mutually engaging gear portions at their adjacent ends connected to the base plate 1 and the supporting plate 2 by means of bolts 5,5', respectively. Furthermore, the opposite ends of the arms are extruded with a needle eye configuration ensuring a simple pivotal function when nested in the complementary hemispherical shaped engaging portion of the connecting nuts 8,8' being preferentially extruded of light metal as well. Rivets inserted through the needle eyes of the arms can be applied as locking means to ensure link connection between the connecting nuts 8,8' and the arms.

As shown in Fig. 2 illustrating the pantograph jack in its raised engaging position the supporting arms are extruded with different lengths. The second upper arm 4 and the second lower arm 7 being longer than the first upper and lower arms 3,6 ensure that by rotating an operating (slit) member 10 by means of a crank handle (not shown in the Figure) the raising supporting plate will engage the vehicle body parallely to the tilting angle of the elevated vehicle.

Fig. 3 showing the pantograph jack in a sectional view taken along line I-I of Fig. 2 illustrates further advantages of the pantograph jack showing supporting arms 4,7, the base plate 1 and the supporting plate 2 integrally extruded with all base features and details.

First of all the flexibility of the extrusion process allows to adjust the wall thickness and width of the arms to the specified load and offers a wide scale of varying the actual cross- sectional configuration of the arms from the shown hollow shape having partition/reinforcing walls to a solid cross-section to comply with the requested strength of the arms. Furthermore, the integrally extruded complementary shaped gear portions engage the adjacent arms over the whole width, something which substantially improve the stability and strength of the pivotal connection between the arms (guiding function) , eliminating use of special reinforcing parts and preventing to take special measures during assembling of the jack apparatus.

Finally, as an inherent feature of the applied manufacturing process the resulting supporting arms being simply cut into the predetermined width in a plane normal to the extrusion direction are characterized by uniform homogen material structures.

The base plate and supporting plate can also be advantageously extruded with all details and auxiliary functions in one opera¬ tion. Thus, the base plate 1 can be provided on the bottom surface with protruding parts 11 ensuring stability even if used on uneven ground. There is also possibility to provide the top supporting plate 2, the base plate 1 or both of them as an integral part of the extruded supporting arms without departing from the scope of the present invention.

Other materials than the above mentioned Al-alloys may be applied in connection with provision of readily extruded jack parts, e.g. magnesium and its alloys or light metals reinforced by means of refractory particles distributed in metal matrix (PMMC composite materials) .

Claims

1. A pantograph jack apparatus comprising a base plate (1) and a supporting plate (2) , a threaded horizontally extending shaft member (9) and con¬ necting nuts (8,8') cooperating with and threaded on the shaft member (9) , first (3) and second (4) upper arms each having one end pivotally connected to the supporting plate (2) and the other end being pivotally connected to the connecting nuts (8,8*) and first (6) and second (7) lower arms each having one end pivotally connected to the base plate (1) and the other end to the connecting nuts (8,8•) , c h a r a c t e r i z e d i n t h a t the supporting arms (3,4,6,7) are readily extruded of light metal material with all details compris¬ ing integrated complementary shaped gear portions at their ends connected to the supporting plate (2) and the base plate (1) of the apparatus.

2. The apparatus according to claim 1, c h a r a c t e r i z e d i n t h a t at least the supporting arms (3,4,6,7) are made of

Al-alloy.