GB2184407A

GB2184407A - Apparatus for preventing unauthorized operation of a vehicle with a steering shaft

Info

Publication number: GB2184407A
Application number: GB8628560A
Authority: GB
Inventors: Lukas Matt; Karl Mettler
Original assignee: Supervis
Current assignee: Supervis
Priority date: 1985-11-28
Filing date: 1986-11-28
Publication date: 1987-06-24
Also published as: AT390767B; GB8628560D0; ATA347385A; DE3640291A1

Abstract

Apparatus for preventing unauthorized operation of a vehicle with a steering shaft (1) comprises a helical spring (10) which surrounds, for part of its length, the steering shaft (1) and for the remainder of its length an extension portion (11) of a sleeve (7) which is fixed to an outer column (18). One end of the spring is fixed to the sleeve and the other end (12), which is disposed in the region of the steering shaft (1), is connected to an adjustable lock bolt (14). By actuating the lock bolt (14) the coils of the helical spring are pressed close against the steering shaft (1) to prevent rotation thereof in one direction. In a modification two springs are provided which prevent rotation of the shaft in both directions. <IMAGE>

Description

SPECIFICATION Apparatus for preventing unauthorized operation of single-or multiple-tracked vehicles with a steering shaft The invention relates to an apparatus for preventing unauthorized operation of single- or multiple-tracked vehicles with a steering shaft, in particular of motor vehicles, the apparatus acting upon the periphery of the steering shaft and restraining or preventing the rotation thereof and comprising at least one sleeveshaped or annular checking member which encloses the steering shaft on at least part of its length, the sleeve-shaped or annular checking member embracing the steering shaft with non-positive or friction locking and the friction locking produced between the chassis of the vehicle and the steering shaft by way of the checking member being variable with respect to its magnitude, while an adjustable lock bolt lifts the checking member-which is essentially stationary relative to the chassis of the vehicle-off the steering shaft.

Apparatus of this type are known per se, for example from the German Offenlegungsschrift (Laid-Open Specification) 32 08 375 and the German Patent 32 16 168. These apparatus are made extremely complicated and are therefore expensive and on account of their numerous parts are also susceptible to breakdown. A simpler design is disclosed in the German Offenlegungsschrift 33 39 065, which is provided with a torque limit. If a torque, which exceeds the value of the aforesaid torque limit and which is furthermore of such magnitude that the motor vehicle cannot be steered in a viable manner, is exerted upon the locked steering shaft, the steering shaft will spin freely under the torque lock. Torque locks of this type prevent the safety device from being destroyed or at least damaged by a great expenditure of energy by way of the steering wheel.In the case of the latter design the steering shaft is provided on its periphery with groove-like depressions in which are disposed rolling members which are held by a sleeve receiving the steering shaft in the manner of a rolling member cage. These rolling members are enclosed by a helical spring. The said sleeve comprises openings which are arranged on its periphery and into which a lock bolt may be inserted. This design is not advantageous. since it will hardly be possible to extend the helical spring radially and to make it increase its diameter in such a way that the rolling members can roll off over the said groove-like depressions.

In addition, an apparatus of this type is known from the European Application 129 522, in which a sleeve, into which a lock bolt of a stationary lock engages, is mounted on the steering shaft. The said sleeve is connected to the steering shaft in a non-positively locking manner by way of friction linings. If the sleeve is held by way of the lock bolt and a suitably high torque is exerted upon the steering shaft, the steering shaft is turned relative to the said friction linings. In this connexion the friction linings are constructed as tapered sleeves which are inserted in correspondingly shaped recesses in the edge of the aforesaid sleeve and are held there by flanging over the edge of the sleeve.It is not entirely easy, during mass production, to insert these friction linings in such a way that a consistent positive and non-positive locking of equal force can be achieved in every case.

In the case of another design (German Offenlegungsschrift 27 30 685) a lock bolt of a stationary lock engages in a toothed wheel, the tooth flanks of the said toothed wheel being made sloping relative to the plane of the wheel itself. This toothed wheel is traversed with play by the steering shaft. A helical spring which is likewise traversed by the steering shaft is connected at one end to the steering shaft and at its other end it supports the aforesaid toothed wheel. When a suitable force is exerted upon the steering shaft and when the lock bolt is inserted, the aforesaid toothed wheel gives way laterally on account of its mounting, and as soon as the advanced lock bolt and the next tooth gap coincide this lock engages again. This alternating engagement and disengagement results in substantial knocks to the structural components, which is not considered desirable.

The invention takes as its starting point these known designs and has as its object to simplify these apparatus in terms of their design and to ensure their operation despite this simplification.

This object is attained according to the invention in that the checking member is constructed as a helical spring and the helical spring is traversed by the steering shaft over at least part of its axial length and the end of the helical spring disposed in the region of the steering shaft is connected to the adjustable lock bolt, and the other end of the helical spring is rigid relative to the chassis.

In order to explain the invention in greater detail, embodiments thereof are illustrated and described below. In the drawings, Figure 1 shows a first embodiment, partly in section; Figure 2 is an elevation or a partial section of a further embodiment, which represents a direct further development of the design shown in Fig. 1, and Figure 3 is a section along the line Ill-Ill in Fig. 1.

In all the drawings the same or similar parts have been given the same reference numerals.

Only a short portion of the steering shaft 1 is shown in each case, and the steering wheel and the steering mechanism are not shown, nor the mounting nor those structural mea sures which contract the steering shaft in the event of a collision.

According to the embodiment illustrated in Fig. 1 the steering shaft 1 is constructed as a tube onto which is pressed a checking member 2.

In the case of the embodiment according to Fig. 1 the checking member 2 is formed by a helical spring 10. In this connexion, a sleeve 7, through which the steering shaft 1 passes and which is secured in an outer column 18, is provided with a tubular extension 11 in which the steering shaft 1 extends. The steering shaft is offset with respect to its diameter, so that a shoulder is formed by the offset 8, in which case the external diameter of the tubular extension 11 of the sleeve 7 and the portion of the steering shaft 1 extending outside the said extension 11 are approximately equal in magnitude. A helical spring 10 is now pressed onto this extension 11 as a checking member 2, and it need no longer be secured here on this extension 11 by structural means; the friction locking existing between the extension 11 and the helical spring 10 is sufficient for secure holding.This helical spring 10 is pressed so far onto this extension 11 of the sleeve 7 that this extension projects into half the helical spring 10. The other half of the helical spring 10 is traversed by the steering shaft 1, namely by the portion having the greater diameter. The free, laterally remote end 12 of the helical spring 10 is connected in a positively locking manner to a lock bolt 14 rotatable at this point about an axis 13.

The axis 13 of the lock bolt extends approximately at right angles to the axis of the steering shaft 1 inside the the helical spring 10 and is rotatable in any direction (arrow 16) by way of the steering wheel. If the apparatus is secured, however, which takes place by rotating the lock bolt 14 clockwise (arrow 15, Fig. 1), the individual coils of the helical spring 10 are positioned about the steering shaft 1 and thus form a secure friction locking, so that the steering shaft 1 can no longer be turned in the winding direction of the helical spring 10.

In this case, however, it is possible to rotate the steering shaft 1 in the opposite direction thereto. It is no longer possible, however, to use the motor vehicle viably in such a case. In order for the friction areas which can be attained by the embrace of the helical spring to be made large, the wire from which the helical spring is wound is advantageously formed with a polygonal, preferably rectangular cross section.

The structural principle shown in Fig. 1 is doubled as it were in the embodiment accord ing to Fig. 2. In this case, on account of the paired arrangement of the springs 10 the steering shaft 1 is locked in both directions of rotation when secured. The two helical springs 10 used as looping springs are made com pletely identical and are arranged with the same direction of winding with reference to a longitudinal direction of the steering shaft.

Their mutually adjacent free ends 12 are gripped in a common lock bolt 14, which is mounted rotatably here. The sleeves 7 for receiving the steering shaft are provided in pairs at a distance from one another, and their tubular extensions 11 face one another. Each of these sleeves 11 supports a looping spring constructed in the form of a helical spring 10, the arrangement being such that the mutually facing free ends 12 of the said helical springs or looping springs lie close to one another. By rotating the lock bolt 14 the coils of the two helical springs 10, which cover the steering shaft 1, are closed around the latter and thus prevent it from rotating in both directions.A pipe connexion 17 is welded laterally on the outer column 18 receiving the structural components described, and covers the opening 25 in the outer colum 18 through which [opening] the ends 12 of the helical springs 10 received by the lock bolt 14 project. The lock, which is operatively connected to the said bolt 14, is inserted and secured in the pipe connexion 17. The magnitude of the torque to be set can be established by the number of coils of the spring 10 which surround the steering shaft 1 in each case.

The arrangement according to Figs. 1 and 2 can be made in such a way that the apparatus is not secured, i.e. the steering shaft 1 is freely rotatable, when the looping springs or helical springs 10 are released. By actuating the lock bolt 14 the springs are tensioned and the apparatus is thereby secured, and the rotation of the steering shaft 1 at least in one direction (embodiment according to Fig. 1) is blocked.

It is also possible to make the arrangement in the two embodiments 1 and 2 such that when the apparatus is not secured the helical springs 10 are pretensioned, i.e.-in the case of the embodiment according to Fig. 2 for example-when the apparatus is not secured the bolt member 14 holds the ends 12 of the two springs 10 displaced against the force of the springs, so that the coils of the looping springs are raised from the steering shaft 1. In order to actuate the apparatus the lock bolt 14 is then turned in such a way that the ends 12 of the pretensioned springs draw close to one another and thus embrace the region covered by the helical springs.

The structural design of the embodiments of the invention described above is extremely simple and hence also reliable in operation and not susceptible to failure.

The apparatus can be actuated indepen dently of the respective angular position of the steering wheel and thus of the steering shaft 1, and so the steering shaft 1 can be locked in any desired position.

The steering wheel lock is advantageously coupled to the ignition switch of the motor vehicle or is directly operatively connected thereto, in such a way that when the ignition is switched off and when the ignition key is withdrawn this lock is actuated.

Claims

1. Apparatus for selectively immobilising or freeing a shaft mounted for rotation around its longitudinal axis, comprising a helical spring enclosing at least part of the length of the shaft, means for immobilising one end of the spring, and means movable generally transversely in relation to the shaft axis attached to the other end of the spring: whereby the turns of the spring open or close in dependence upon the movement of the transversely movable means and thereby release or grip the surface of the shaft.

2. An apparatus for preventing unauthorized operation of vehicles with a steering shaft in particular motor vehicles, the apparatus acting upon the periphery of the steering shaft to restrain or prevent the rotation of said shaft about its longitudinal axis, said apparatus comprising at least one sleeveshaped or annular checking member which encloses the steering shaft over at least part of its length to provide non-positive or friction engagement of variable magnitude, while an adjustable lock bolt lifts the checking member from contact with the steering shaft, characterized in that the checking member is constructed as a helical spring traversed by the steering shaft (1) over at least part of its axial length, one end of the helical spring being disposed in the region of the steering shaft and connected to the adjustable lock bolt and the other end being fixed relative to the chassis of the vehicle.

3. An apparatus according to Claim 1 or 2, characterized in that the fixed end portion of the helical spring is pressed with frictional engagement over a stationary sleeve through which by the shaft passes.

4. An apparatus according to Claim 3, characterized in that the external diameters of the sleeve and of the shaft region covered by the helical spring are approximately equal.

5. An apparatus according to any one of Claims 1 to 4, characterized in that the shaft passes through two axially spaced sleeves each of which supports a different helical spring, the two helical springs facing one another with the opposed ends both adjustable by way of a common lock bolt constituting the transversely movable means.

6. An appartus accoring to Claim 5, characterized in that the lock bolt has a body rotatable about an axis approximately at right angles to the axis of the steering shaft.

7. An apparatus according to any one preceding claim, characterized in that the helical spring is formed of wire having a polygonal, preferably rectangular, cross-section.

8. Apparatus as claimed in claim 1 substantially as herein described with reference to and as illustrated in the accompanying drawings.