GB1596781A

GB1596781A - Locking devices

Info

Publication number: GB1596781A
Application number: GB475877A
Authority: GB
Original assignee: Henry Squire and Sons Ltd
Current assignee: Henry Squire and Sons Ltd
Priority date: 1978-02-17
Filing date: 1978-02-17
Publication date: 1981-08-26

Description

(54) IMPROVEMENTS IN OR RELATING TO LOCKING DEVICES (71) We, HENRY SQUIRE & SONS, a British unlimited Company registered under the Companies Acts 1948-1967, of New Invention, Willenhall, in the County of Stafford, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement::- This invention relates to locking devices of the kind comprising a lock body incorporating a key-operable locking mechanism and a pair of openings, in which are received respective ends of an elongate flexible locking element, one of said ends (herein called "the fixed end") being nonreleasably secured within its associated opening and the other of said ends (herein called "the free end") being releasably received in its associated opening under the control of the locking mechanism. Such locking devices are hereinafter referred to as being of the kind specified.

The invention is more particularly, but not exclusively, concerned with locking device- of the kind specified wherein said openings are arranged with their axes extending transverse to one another, but certain aspects of the invention, as will hereinafter be apparent, are applicable to a locking device of the kind specified wherein said openings are arranged with their axes mutually parallel, or substantially so.

Where the openings are transverse to one another it is usual to make the lock body as a die-casting with the opening for the fixed end of the locking element defined by a tubular extension of the body within which an end portion of the locking element is received and retained by deformation of the tubular extension. Unfortunately, this method of fixing the locking element constitutes a weak point due to the frangibility of die-castings after such deformation, and the force required to pull the fixed end of the locking element out of the body is undesirably low, for example less than about 500 Ibs.

According to the invention we provide a locking device of the kind specified wherein the locking element is provided with a terminal member at its fixed end, which terminal member includes a head portion arranged to engage within the lock body a corresponding abutment surface around the inner end of the opening in which the terminal member is received so that withdrawal of the fixed terminal member from that opening by means of a tensile force applied to the locking element is positively resisted by abutment between the head portion of the terminal member and the abutment surface within the lock body.

Preferably, the head member is of frustoconical form and the abutment face is of complementary form.

The terminal member may be made of steel or other material which can suitably be deformed without introducing weakness, for example by forming dimples to grip the end of the elongated locking element which is inserted into an internal bore formed in the terminal member.

Such terminal member may be utilised in locking devices of the kind specified in which the openings are mutually transverse and in those in which they are mutually parallel.

Preferably, a further terminal member is similarly attached to the free end of the locking element and if, apart from the head portion of the fixed end terminal member, the cross-sectional dimensions of the locking element and of both terminal members are less than the corresponding dimensions of the opening in which the fixed end terminal member is received, the two terminal members can be secured to a length of cable and the complete locking element can be assembled with the lock body by passing the locking element, free end first, through the body. Alternatively, the free end terminal member could be secured to the cable only after the fixed end terminal member is assembled with the lock body.Whilst the locking element typically consists of a cable, it could be formed as a length of chain, and in such a case the terminal members could then be apertured to receive the end links of the chain, which would preferably be secured to the fixed end terminal member after the latter is assembled with the lock body.

We have found that this method of securing the fixed end of the locking element gives such an improvement in the force required to pull the fixed end out of the lock body even when the latter is formed as a zinc-based die casting (typically the force required is at least three times greater than is necessary with the best prior design known to us) that it becomes desirable to improve the arrangement whereby the free end terminal member is locked within the body at least where the openings are mutually transverse.

In such locking devices, the locking mechanism may include a pin projecting eccentrically from the end of a rotary barrel which is rotatable by means of the key about an axis which extends transverse to the axis of the opening in which the free end terminal member is received, the pin being so arranged as to be movable, upon rotation of the barrel, between a locking position in which the pin extends into the opening to engage in an appropriate recess formed in the free end terminal member, and a releasing position in which the pin is clear of said opening so as to allow the free end terminal member to be withdrawn therefrom.

We have found that in known designs of such locking devices the eccentric pin constitutes the weakest point in that it can be deflected from its locking position towards its releasing position by a tensile force applied to the free end terminal member which the pin engages.

Thus, in accordance with a further feature of the present invention we provide, in such a locking device the eccentric pin is supported at the end thereof remote from the barrel of the locking device against lateral displacement or deformation of the pin in a direction away from the free end terminal member.

One way in which this can be achieved is by providing at the free end of the pin a disc-like head which is centred on the axis of rotation of the barrel and engages a corresponding bearing surface afforded by the body. An alternative arrangement is to provide a peg which supports the free end of the pin. Such peg could be provided on the free end of the pin itself, but in a particularly convenient arrangement the peg is provided at the inner end of the fixed end terminal member, the two openings in the lock body being so arranged relative to the locking mechanism that the peg is disposed in alignment with the axis of rotation of the barrel at a position adjacent to the opening in which the free end terminal member is received.

These and other features of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a view of one embodiment of locking device of the kind specified in side elevation; and Figures 2 and 3 are respective sections on the line A-A and B-B of Figure 1.

Referring to the accompanying drawings, there is shown a locking device of the kind specified including a die-cast body 10 having at one end a tubular extension 11 defining, in part, an opening 12 within which is received a terminal member 13 attached to one end of a locking element, in this instance in the form of an elongated cable 14, which member 13 is inserted into a bore 15 formed in the terminal member, and secured thereto by means of dimples 16 pressed into the exterior surface of the terminal member 13. The terminal member is formed from a material such as steel which is sufficiently ductile to enable this type of fixing to be used.

The other end of the cable 14 carries a further similarly attached terminal member 17 which is releasably received within a transverse opening 18 formed in the body 10. The terminal member 17 is formed with an annular recess 19 adapted to receive a locking pin 20 which is formed as an extension of a lock barrel 21 which forms part of a key-operable locking mechanism indicated generally at 22. As can be seen, the pin 20 is of sector form in section having a part-cylindrical face 22a and flat face 22b.

The pin is arranged parallel to, but offset from the axis of rotation 23 of the lock barrel 21 and is thereby rotatable within an inner extension 24 of the opening 12. In its locking position, as shown in Figures 2 and 3, the pin 20 extends partly into the transverse opening 18, the latter intersecting the opening extension 24. In this position the pin 20, which is preferably of complementary shape to that of the recess 19, enters the recess 19 and prevents the terminal member 17 being withdrawn from the opening 18, as can most clearly be seen in Figure 3.

When the lock barrel is rotated by means of the key, the pin 20 is itself rotated about the axis 23 to take up a position on the opposite side thereof entirely within the opening 24, whereby it is clear of the opening 18 so that the terminal member 17 can be withdrawn.

In accordance with the first feature of the present invention, the fixed end terminal member 13 is formed with a head portion 25 which, as shown, is preferably of frustoconical form, and the junction between the opening 12 and the opening extension 24 is tapered so as to afford complementary frusto-conical abutment surface 26 which is engaged by the head portion 25 of the terminal member 13. As can be seen, the length of the terminal member 13 is such that the head portion 25 thereof is disposed within the main part of the lock body 10 where the abutment surface 26 is backed up by a substantial thickness of die-cast metal.

With this arrangement, we have found that it is readily possible to ensure that the fixed end terminal member 13 cannot be pulled out of the lock body when the body is formed as a zinc-based die-casting without applying a force of over 1,600 Ibs. This represents well over a three-fold improvement relative to the best available locking device of the kind specified known to us wherein the cable is secured by dimpling the tubular extension of the diecast lock body itself to secure the cable therein.

Conveniently, the fixed end terminal member 13 is formed with a groove 27 and the free end portion 28 of the tubular extension 11 is turned over into the groove 27, primarily for the purpose of preventing the terminal member 13 being pushed inwardly of the body.

In accordance with a further feature of the invention, the head portion 25 of the fixed end terminal member 13 is formed with an axially extending peg 29 which is centred on the axis of the rotation 23 of the lock barrel 21. The peg 29 supports the pin 20 at the free end of the latter. In the embodiment illustrated, the flat face 22b of the pin 20 is formed with a longitudinal groove 31, and the peg 29 engages the shoulders of such groove.

With this arrangement, we have found that it is readily possible to ensure that the force required to pull the free end terminal member 17 out of the opening 18, when locked therein, exceeds 1,200 Ibs, and this represents an almost three-fold improvement over the best locking device of this type previously known to us, because the pin is supported against deflection or deformation in a direction substantially radially away from the axis of the terminal member 17.

The two terminal members 13 and 17 are so dimensioned that, except for the head portion 25, they can pass through the opening 12 before the end portion 28 is deformed inwardly as shown in Figure 1.

Thus, the terminal members 13 and 17 are first attached to the ends of the cable 14 and then the free end terminal member 17 and the cable 14 itself are passed through the lock body until the fixed end terminal member 13 is positioned in the opening 12 as shown in Figure 2. The locking mechanism 22 is then inserted into the lock body 10 through an opening 32 and an end plate 33 is positioned in said opening.

Thereafter, the periphery 30 of the body around the opening 32 is deformed inwardly so as to retain the end plate 33 and locking mechanism 21, and at the same time the free end 28 of the tubular extension 11 is turned inwardly into the groove 27 of the terminal member 13. A protective plastic sleeve may then be passed over the cable 14 and retained by means of a plastic plug 34 which is assembled with the free end terminal member 17.

Whilst it is particularly convenient to support the free end of the locking pin 20 by means of the peg 29 which is provided on the terminal member 13, it will be appreciated that other arrangements are possible. For example, the head portion 25 of the terminal member 13 could be formed with a central recess and the pin 20 itself could carry a peg arranged on the axis 23 to enter such recess. If, for any reason, the opening 12 is not aligned with the barrel 21 of the lock mechanism, it would be possible for the free end of the pin 20 to be supported by a peg or other projection afforded by the body itself, or by a peg carried by the pin entering into a recess afforded by the body itself. In a further alternative arrangement, the pin 20 could carry at its free end a disc-like head member which is rotatable within the opening extension 24.This could most conveniently be formed by milling away material from a cylindrical extension of the lock barrel 21 to define the pin and the head member thereof.

Whilst the invention has been described particularly with reference to the type of locking device of the kind specified wherein the openings 12 and 18 extend transversely relative to one another, it will be appreciated that the frusto-conical head portion 25 and complementary abutment face 26 may also be utilised in a locking device of the kind specified wherein the two openings extend substantially parallel to one another. In this case, if the free end terminal member 17 is locked by means of a rotatable pin similar to the pin 20, then the free end of such pin could also be supported in some suitable manner.

Of course, whilst the lock described has a body formed as a die-casting, the present invention is not restricted to locking devices of the kind specified wherein the body is formed as a die-casting, and especially where the openings are parallel the body could be formed from laminated steel plates for example.

WHAT WE CLAIM IS 1. A locking device of the kind specified wherein the locking element is provided with a terminal member at its fixed end, which terminal member includes a head portion arranged to engage within the lock body a corresponding abutment surface around the inner end of the opening in which the terminal member is received so that withdrawal of the fixed terminal member from that opening by means of a tensile force applied to the locking element is positively resisted by abutment between the head portion of the terminal member and the abutment surface within the lock body.

2. A locking device according to Claim 1 wherein the head member is of frustoconical form and the abutment face is of complementary form.

3. A locking device according to Claim 1 or Claim 2 wherein the terminal member is secured to the locking element by means of local deformation of the terminal member.

4. A locking member according to Claim 3 wherein the terminal member is formed with an internal bore which receives the end of the elongated locking element, and the latter is retained within the bore by forming dimples in the terminal member to grip the end of the elongated locking element.

5. A locking device according to anyone of claims 1 to 4 wherein the openings are mutually parallel.

6. A locking according to anyone of Claims 1 to 4 wherein the openings are mutually transverse.

7. A locking device according to anyone of the preceding claims wherein a further terminal member is attached to the free end of the locking element.

8. A locking device according to Claim 7 wherein the cross-sectional dimensions of the locking element and of both terminal members except for the head portion of the fixed terminal member are less than the corresponding dimensions of the opening in which the fixed end terminal member is received, and the two terminal members are secured to the locking element before the latter is assembled with the lock body.

9. A locking device according to anyone of the preceding Claims wherein the locking element is formed as a cable.

10. A locking device according to anyone of the preceding Claims, wherein the locking mechanism includes a pin projecting eccentricity from the end of a rotary barrel which is rotatable by means of the key about an axis which extends transverse to the axis of the opening in which the free end terminal member is received, the pin being so arranged as to be movable, upon rotation of the barrel, between a locking position in which the pin extends into the opening to engage in an appropriate recess formed in the free end terminal member, and a releasing position in which the pin is clear of said opening so as to allow the free end terminal member to be withdrawn therefrom.

11. A locking device according to Claim 10 wherein the eccentric pin is supported at the end thereof remote from the barrel of the locking device to against lateral displacement or deformation of the pin in a direction away from the free end terminal member.

12. A locking device according to Claim 11 wherein there is provided at the free end of the pin a disc-like head which is centred on the axis of rotation of the barrel and engages a corresponding bearing surface afforded by the body.

13. A locking device according to Claim 11 wherein a peg is provided to support the free end of the pin.

14. A locking device according to Claim 13 as appendant to Claim 6, wherein the peg is provided at the inner end of the fixed end terminal member, the two openings in the lock body being so arranged relative to the locking mechanism that the peg is disposed in alignment with the axis of rotation of the barrel at a position adjacent to the opening in which the free end terminal member is received.

15. A locking device of the kind specified substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. could be formed from laminated steel plates for example. WHAT WE CLAIM IS

1. A locking device of the kind specified wherein the locking element is provided with a terminal member at its fixed end, which terminal member includes a head portion arranged to engage within the lock body a corresponding abutment surface around the inner end of the opening in which the terminal member is received so that withdrawal of the fixed terminal member from that opening by means of a tensile force applied to the locking element is positively resisted by abutment between the head portion of the terminal member and the abutment surface within the lock body.