GB2075930A

GB2075930A - Hydraulic locking unit for locking tippable driving cabs of lorries

Info

Publication number: GB2075930A
Application number: GB8112989A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-04-29
Filing date: 1981-04-28
Publication date: 1981-11-25
Also published as: IT1142412B; GB2075930B; DE3016545A1; IT8148349A0; DE3016545C2; SE444799B; FR2481220B1; SE8102392L; FR2481220A1

Abstract

In a hydraulic locking unit for locking tippable driving cabs an intermediate member (9) is installed between the shock absorber (2) and/or spring (8) arrangement for the driving cab (10) and the driving cab itself, thereby ensuring that, at the end of the spring travel, the driving cab cannot tip when a receiving member (11) fixed to the cab 10 receives a locking member (13) arranged on the member 9. The arrangement allows the cab to be locked from tipping without eliminating its spring suspension. <IMAGE>

Description

SPECIFICATION Hydraulic locking unit for locking tippable driving gas of lorries This invention relates to a locking unit for locking tippable driving cabs or compartments of lorries, as set forth in the classifying (i.e. non-characterising) portion of Claim 1.

A locking unit of this kind is known (DOS No. 22 24 383). With this known arrangement, the locking action in respect of the tippable driving cab or compartment is released at the very moment as soon as the pump is actuated, to supply pressure fluid to the hydraulic cylinder which serves for tipping the driving cab. The known locking unit ensures that the pressure fluid can be supplied to the tipping cylinder only when the locking unit is completely released, that is to say, when the locking member of the locking unit is in the non-locked position.

The known locking unit provides a degree of safety and has been widely accepted for that reason. A disadvantage is that, when the locking unit is mounted generally in the rearward region of the driving cab approximately in the middle between the two shock absorber and/or spring arrangements, the springing properties thereof should not be detrimentally affected. Accordingly, the locking unit must have a certain amount of play which permits a slight tipping movement of the driving cab, which is highly undesirable. Expensive and complicated accessory devices are required to eliminate this disadvantage.

Added to this is that, in this arrangement, the driving cab is not secured in the region of the support means for the shock absorber and/or spring arrangements.

The present invention is therefore based on the problem of so designing a locking unit as set forth in the classifying portion of Claim 1, that the springing properties of the driving cab are not detrimentally affected, while providing at the same time for sure and reliable locking.

According to the present invention, a hydraulic locking unit for locking tippable driving cabs of lorries, comprises a hydraulic tipping cylinder having a feed line which comes from a pump and which is taken by way of a control slide valve, in which feed line, besides at least one hydraulically releasable non-return valve, for locking purposes, there is provided a hydraulic cylinder which is actuated on the one hand by the hydraulic fluid in the release direction and on the other hand by a closing spring in the locking direction and which, with its piston, moves the locking member of the locking unit, wherein the hydraulic cylinder and the piston thereof is formed as a control slide valve with two control ports which are disposed one behind the other, one of which is connected to the feed line by way of a non-return valve and the other is directly connected to the feed line, and wherein the latter control port is liberated only when the locking action is released, characterised in that the hydraulic locking unit is formed as an intermediate member for installation between the shock absorber and/or spring arrangement for the driving cab on the one hand, and the driving cab with a receiving member for the locking member on the other hand.

By virtue of the arrangement of the hydraulic locking unit, in the form of an intermediate member, between the support region of the driving cab and the actual shock absorber and/or spring arrangement, the springing properties are not detrimentally affected when the intermediate member is installed, because the driving cab constantly rests on the shock absorber and/or spring arrangement for the driving cab. If this arrangement is relieved of load, for example due to braking and due to the resulting, forwardly directed rotational movement of the driving cab, the mounting member of the driving cab, which is locked by the locking member, ensures, at the end of the spring travel, that the driving cab does not begin to tip in an untimely fashion, without actuation of the tipping cylinder.On the contrary, the driving cab is force-lockingly connected to the chassis frame of the vehicle by way of the two shock absorber and/or spring arrangements, so that, in contrast to the state of the art, the force is transmitted to the chassis frame not at one position but, by way of the two shock absorber and/or spring arrangements, at a total of two positions. Furthermore, the locking unit which is formed as a separate intermediate member can also be subsequently fitted to the tippable driving cabs of lorries, without excessive expenditure. At any event, the locking unit according to the invention does not detrimentally affect the spring suspension qualities of the driving cab, while at the same time giving a very high degree of security in respect of untimely tipping movement.

Advantageous embodiments and developments of the invention are characterised in the subsidiary claims.

Further features, details and advantages of the invention will be apparent from the following description of a preferred embodiment which is shown in the accompanying drawing, which is a diagrammatic cross-sectional view through a shock absorber and/or spring arrangement and a locking unit.

With reference to the drawing, the shock absorber/ spring assembly which is generally denoted by reference numeral 1, comprises a shock absorber 2 which, at its lower end 3, is secured by way of rubber spring members 4 to the frame 5 of the lorry (not shown). Mounted on the movable piston 6 of the shock absorber 2, concentrically with respect to the shock absorber, by way of a support means 7 mounted on the piston 6, is a coil spring 8.

Both the spring 8 and also the shock absorber 2 are fixed to the locking unit which is generally denoted by reference numeral 9 and which is in the form of an intermediate member, on one side thereof. The locking unit 9 is secured to the underside, indicated by reference numeral 10, of the driving cab (not shown), in the support region thereof. Arranged at the underside of the driving cab 10 is a receiving member 11 which is in the form of a pin or bolt member with a shoulder 12 provided at the free end thereof.

The locking unit 9 has a hydraulic cylinder 14 for moving the locking member 13, namely a pin, with the pin 13 being sealed by means of a seal 15 which is disposed therearound. In addition, a closing spring 151 for moving the pin 13 into its locking position is provided on the underside of the piston 16 which is movable in the hydraulic cylinder 14. The piston 16 is also formed as a control slide valve having two control openings or ports (not shown) which are disposed one behind the other and of which one is connected to the feed line by way of a non-return valve while the other is connected directly to the feed line; the last-mentioned control port is liberated by the pin 13 only when the locking action is released.

Provided on one side 17, being the lower side, of the intermediate member, is a screw-threaded bore 18 for receiving a screw-threaded bolt member 19 of the shock absorber 2, the bolt member 19 being secured by a locking nut 20. Disposed concentrically with respect to the screw-threaded bore 18 is an annular support surface 21 for the coil spring 8.

Provided on the side of the intermediate member 9, which is remote from the bottom side 17, is an opening which is generally denoted by 22 and which is preferably in the form of a bore, having a countersunk portion 23. The countersunk portion 23 serves as a guide surfaceforthe shoulder 12 of the receiving member 11. In the locked condition shown in the drawing, the pin 13 engages into the free space of the bore 22, behind the shoulder 12 of the member 11,so that the member 11 and thus the driving cab 10 are form-lockingly or positively connected to the intermediate member 9 and thus force-lockingly connected by way of the assembly 1, to the frame 5 of the vehicle. Advantageously, an annular support means 24 for the underside of the driving cab 10 is arranged concentrically with respectto the bore 22 or the countersunk portion 23.

The support means 24 may preferably be a ring comprising a resilient or flexible material, for example rubber.

Claims

1. A hydraulic locking unit for locking tippable driving cabs of lorries, comprising a hydraulic tipping cylinder having a feed line which comes from a pump and which is taken by way of a control slide valve, in which feed line, besides at least one hydraulically releasable non-return valve, for locking purposes, there is provided a hydraulic cylinder which is actuated on the one hand by the hydraulic fluid in the release direction and on the other hand by a closing spring in the locking direction and which, with its piston, moves the locking member of the locking unit, wherein the hydraulic cylinder and the piston thereof is formed as a control slide valve with two control ports which are disposed one behind the other, one of which is connected to the feed line by way of a non-return valve and the other is directly connected to the feed line, and wherein the latter control port is liberated only when the locking action is released, characterised in that the hydraulic locking unit is formed as an intermediate member for installation between the shock absorber and/or spring arrangement for the driving cab on the one hand, and the driving cab with a receiving member for the locking member on the other hand.

2 < A locking unit according to Claim 1, characterised in that, on one side, the intermediate member has a bearing surface for a coil spring.

3. A locking unit according to Claim 1 or Claim 2, characterised in that, on one side, the intermediate member has a screw-threaded bore for screwing in the one screw-threaded bolt member of a shock absorber.

4. A locking unit according to Claim 2 or Claim 3, characterised in that the bearing surface is of an annular configuration and is arranged concentrically with respect to the screw-threaded bore.

5. A locking unit according to any one of Claims 1 to 4, characterised in that the other side of the intermediate member, which is arranged opposite said one side, has an opening for the receiving member, and that the locking member is movable into the locking position in the free space of said opening.

6. A locking unit according to Claim 5, characterised in that the opening is in the form of a bore, and the locking member which is in the form of a pin is movable into the free space of said opening.

7. A locking unit according to Claim 6, characterised in that the bore has a countersunk portion.

8. A locking unit according to Claim 6 or Claim 7, characterised in that an annular driving cab support means is arranged concentrically with respect to the bore.

9. A locking unit according to Claim 8, characterised in that the support means comprises a resilent or flexible material.

10. A locking unit according to Claim 9, characterised in that the material of the support means is rubber.

11. A hydraulic locking unit for locking tippable driving cabs of lorries, substantially as hereinbefore described with reference to the accompanying drawings.