GB2030107A

GB2030107A - Coupling between a mechanical lifting jack and operating handle

Info

Publication number: GB2030107A
Application number: GB7925256A
Authority: GB
Original assignee: MAN Takraf Fordertechnik GmbH
Current assignee: Takraf GmbH
Priority date: 1978-09-27
Filing date: 1979-07-19
Publication date: 1980-04-02
Also published as: DD138188A1; SE7907415L; NL7905730A; GB2030107B; SE426806B; DE2925425A1

Abstract

A coupling for coupling together a spindle 1 of a mechanical lifting jack and a cranked handle 3 comprises a flat connecting member 2 provided on one end of the spindle 1, said member 2 having a slot to form a hook-like member, and a forked member 4 provided on the cranked handle 3, said member 4 having a transverse bolt 5 engagable in the slot and about which the handle 3 can be universally pivoted by providing suitable clearances as shown. <IMAGE>

Description

SPECIFICATION Coupling between a mechanical lifting jack and operating handle This invention relates to a coupling for cou pling together a spindle of a mechanical lifting jack and a cranked operating handle.

Car jacks, resting on the ground, are often pushed until they are right underneath the vehicle. The shape and construction of the crank handle must be adapted to meet this requirement. To suit the transmission of the torque and corresponding to the more or less inclined crank rod, different couplings (con necting members) have been developed. Already known is a fork with a rectangular counter member, without a locking arrangement, a universal joint which is rigidly attached to the spindle at one end and which carries a square-shaped end to receive the crank handle. Inter alia, a simple method of crank handle fitment resides in the spindle of the car jack having at the end a reinforcement with a transverse hole into which the crank handle, fitted with a hook, is pushed.In contrast to the simple structure of the car jack, the universal joint may be expensive and technically complicated in construction.

Other technical solutions allow the crank handle only minimal angular mobility or do not offer a sufficient locking action for securing the crank handle.

According to the present invention there is provided a coupling for coupling together a spindle of a mechanical lifting jack and a cranked rod of an operating handle, comprising a flat connecting member provided on one end of the spindle or on the cranked rod of the handle, said member being provided with a slot to form a hook-like member, and a forked member provided on the rod of the handle or on one end of the spindle, said forked member having a transverse bolt engagable in the slot and about whose axis the handle can be articulated.

The coupling parts interlock and permit use in a difficult working position. By virtue of a fork locking connecting, the two parts of the coupling will be reliably interlocked to exclude the possibility of unintentional detachment of the crank handle from the jack during operation of the spindle.

The connecting member which may be secured either to the spindle of the jack or alternatively to the crank handle, is intended to be a hook which can be produced from a rectangular flat sheet. The forked member may be bent from rugged sheet metal. Both webs of the fork may be curved and approach each other before the fork ends diverge again at an acute angle. The fork webs are interconnected by a bolt at the point of their greatest proximity. Bolt diameter, distance between the fork webs and the hook opening in the connecting piece are dimensionally adapted to one another so that clearance is provided between the bolt and the hook opening and operatively the transmission of force takes place at the outer edge of the fork, through the contacting connecting piece and the points of contact thereof. Several functions evolve upon the bolt.It prevents the fork webs bending apart from each other and imparts the necessary stability to the fork.

Furthermore, the bolt is a point of articulation for the two parts of the coupling. Its task is to guide the connecting piece while the points of contact of the connecting piece on the fork webs move around the bolt on a part of a circular path. The crank handle is sufficiently reliably locked by the bolt. Engagement and disengagement of the fork is possible only when the fork is disposed in a certain position in relation to the spindle axis. By reason of the dimensional form of the bolt and its distance from the bottom of the fork on the one hand and the hook-shaped opening on the connecting piece on the other, so locking of the crank handle is achieved.

An embodiment of the invention will now be described, by way of an example, with referance to the accompanying drawing, in which Figure 1 shows in section the parts of the coupling between the crank handle and the jack, Figure 2 shows in side elevation the coupling parts in the position of use, Figure 3 shows the connecting piece and fork, in section, and Figure 4 shows the car jack provided with the crank handle.

Fig. 4 shows in side elevation a lifting jack of the scissors type having a screw-threaded spindle 1 provided at one end with a coupling for connecting an operating handle to the jack.

The coupling is shown in greater detail in Figs. 1 to 3 and is an angularly movable connecting member between the spindle 1 of the car jack and the crank rod 3 of the handle. The rod 3 is provided with a fork 4 which can be engaged with a connecting piece 2 mounted on the spindle 1. In order to effect locking of the crank handle in the position of use, engagement of the fork 4 of the crank handle with the piece 2 is possible only at one specific angle in relation to the connecting piece 2. The connecting piece 2 is provided with a slot having a downwardly facing opening, to produce a hook-shaped configuration. The fork 4 fixed on the crank rod 3 consists of bent flat sheer material. Both webs of the fork 4 are connected to each other by a bolt 5.Conditioned by its function, the dimension a between the bolt 5 and the back of the fork 4 must be smaller than the dimension b, but in turn greater than the dimension c. To transmit the rotary movement from the crank handle to the spindle 1 of the car jack, as Fig. 3 shows, the upper edge of one web of fork 4 is applied to one side of the connecting piece 2 and the lower edge of the other web of fork 4 is applied against the other side of the connecting piece 2. In this respect, the bolt 5 only has the task of positioning the fork 4 on the connecting piece 2. The handle can be articulated about the axis of the bolt 5.

Fig. 4 shows a suggested design for the crank rod 3 and the location of a middle handle piece 6 of the operating handle. By cranking the rod 3, it is possible to provide an effective protection for the hand of a person using the crank handle.

It will be appreciated that the piece 2 may be provided on the rod 3 and the fork 4 provided on the spindle 1.

Claims

1. A coupling for coupling together a spindle of a mechanical lifting jack and a cranked rod of an operating handle, comprising a flat connecting member provided on one end of the spindle or on the cranked rod of the handle, said member being provided with a slot to form a hook-like member, and a forked member provided on the rod of the handle or on one end of the spindle, said forked member having a transverse bolt engagable in the slot and about whose axis the handle can be articulated.

2. A coupling as claimed in claim 1, in which the slot in the connecting piece is a curved slot and the dimension between the bolt and the back of the fork is less than the dimension between the end of the connecting piece and the inside of the bend of the slot.

3. A coupling as claimed in claim 1 or claim 2, in which between the fork and the connecting piece there are locally varying points of contact disposed on the outer edges of the fork and the sides of the connecting piece.

4. A jack and crank handle provided with a coupling as claimed in any of claims 1 to 3, in which the cranked handle is provided with a middle handle piece and a portion which can rest on the floor or ground.

5. A coupling for coupling together a spindle of a mechanical lifting jack and a cranked operating handle, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.