GB2364740A

GB2364740A - Securing cylinders in surface mounted locks

Info

Publication number: GB2364740A
Application number: GB0116830A
Authority: GB
Inventors: Andrew Allan Staines
Original assignee: Surelock McGill Ltd
Current assignee: Surelock McGill Ltd
Priority date: 2000-07-10
Filing date: 2001-07-10
Publication date: 2002-02-06
Anticipated expiration: 2021-07-10
Also published as: GB0016922D0; GB2364740B; GB0116830D0

Abstract

An actuating mechanism for a lock comprises a housing(5) mountable within a cylindrical recess (4) of a door (1). The front of the housing (5) has a hole therein through which a key passes, and a lip which abuts the front face (2) of the door (1) when in use. A cylinder (20A, 20B, 20C) is retained within the housing (5) by means of a rear plate (21) screwed to the rear of the housing (5). To prevent relative movement of the cylinder and the housing, one or more shims (30, 30A, 30B) are used to pack any gap between the rear of the cylinder (20A, 20B, 20C) and the rear plate (21) so that the cylinder is sandwiched between the front face of the housing (5) and the rear plate (21). A tang (35) extends rearwardly from the cylinder and engages with a bolt actuator.

Description

<Desc/Clms Page number 1> ACTUAfING MECHANISM FOR LOCK This invention relates to an actuating mechanism, in particular for use with a surface-mounted lock. Mortice locks are well know for installation into the door frames. However, their installation weakens the door frame and allows them to be broken or damaged by application of force to the lock mechanism or door.

Surface-mounted locks are mounted against a plane surface of the door rather than into an edge of it. A rim cylinder or the like passes through a hole in the body of the door and engages the surface mounted lock on the other side of the door. Once again, however, such locks are in general relatively easy to attack by force, for example by striking the cylinder with a hammer or drilling out. Often, by applying force to the door, the frame thereof may be broken. For increased security, a number of surface-mounted locks may sometimes be used around the perimeter of a door frame.

To improve damage resistance, cylinder guards have been employed in connection with various rim cylinders. However, each of these arrangements suffers from the requirement to load the cylinder through the front of the cylinder guard. This in turn allows the front of the rim cylinder to be attacked with a punch or the like.

According to the present invention, there is provided an actuating mechanism for a surface mounted lock comprising: a housing having a front plate for abutment with a face of a door, and a hollow cylindrical portion extending rearwardly from the front plate; a cylinder insertable through the rear of

the housing and fixed within the housing; a barrel rotatably mounted within the cylinder, arranged to receive, in use, a key through the front plate, and being arranged, in use, to operate a bolt actuator of a surface mounted lock on the rear face of the door; wherein the cylinder is sandwiched in the housing between the rear face of the front plate and a rear plate mounted to the rear of the cylindrical portion of the housing with at least one shim between the rear of the cylinder and the plate, the or each shim or the plate having an opening in which the cylinder is received to prevent it moving transversely to the direction of the axis about which the barrel is rotated.

The use of shims allows a housing of one size to be used for a number of different cylinders, whilst also allowing the cylinder to be mounted via the rear of the housing and still held in place to limit or prevent transverse movement or rotation thereof within the housing.

Although the present invention can be used with a profile cylinder, it has been specifically designed to be used with a rim cylinder in which a tang projects rearwardly from the rear end of the barrel.

The opening which prevents transverse movement of the cylinder can be circular so as to fit exactly the outer surface of the cylinder. However, preferably, having an oval opening provides an actuator mechanism which can accommodate various different rim cylinder configurations.

Although the rear end of the cylinder can be supported against transverse movement by an opening in the plate, it is more convenient for this support to

be provided by an opening in the or each shim.

In this case, each shim preferably has a non- circular external shape which fits closely with the internal face of the cylindrical portion which is correspondingly shaped. This allows the shims to be correctly aligned thereby facilitating assembly and also prevents rotation of the shims in use.

In a particularly preferred embodiment, the or each shim includes an outwardly facing, radially projecting lug arranged in use to be received by a corresponding axially extending slot formed in the internal face of the cylindrical portion of the housing.

In one particularly preferred embodiment, the or each shim together form a packing member whose axial length is substantially the same as or greater than the distance between the rear of the cylinder when inserted into the housing and the rear of the cylindrical portion of the housing to which the rear plate is mounted, such that the cylinder is firmly clamped to prevent axial rotation thereof when the rear plate is mounted.

.The cylinder is typically limited in its rotation even when the shim or shims form a packing member shorter than the distance between the rear of the cylinder and the rear of the cylindrical portion. However, by using a. packing member which is at least as long as that distance, the rear plate can be screwed or otherwise affixed to the housing so as to firmly clamp (as opposed to merely sandwiching) the shims to the rear of the cylinder. This in turn prevents any rotation of the cylinder, minimising the risks of attempted damage to the mechanism.

In a particula-rly preferred embodiment, prevention of relative rotation is also achieved by using a peg such as a socket set screw which extends from the cylinder through apertures in the or each shim.

In order to provide further protection against drilling of the cylinder, a disc with a through slot is preferably rotatably retained between the front face of the cylinder and the rear face of the front plate to overlie a key slot in the front of the barrel, whereby when the disc is in a certain rotational orientation, access to the key slot is available through the slot.

In order to provide a further level of protection, the front plate preferably projects radially outwardly of the hollow cylindrical portion to define a peripheral lip, and a recess is provided in a rear facing surface of the lip around its entire circumference. Thus, if the front plate is attacked using a chisel, the weak spot is this lip, rather than any of the screws holding the housing in place.

The invention also extends to a combination of a door, a mounting plate and the above actuating mechanism. In that case, the mechanism is externally shaped so as to be insertable in a cylindrical recess in the door, the mechanism in use, being held in place within the said cylindrical recess in the door by fixing means passing from the mounting plate, located on a first face of the door, and into engagement with the housing of the mechanism such that the front face thereof abuts with a second, opposite face of the door. In that case, most preferably, a lock mechanism is mounted on the said first face of the door, the lock mechanism being actuatable by insertion of the key through the said front plate of the mechanism

housing. An example of an actuating mechanism constructed in accordance with the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a section through an actuating mechanism employing a first type of rim cylinder; Fig. 2 is a view similar to Fig. 1 employing a second type of rim cylinder; Fig. 3 is an exploded view of the actuating mechanism of Figures 1 and 2 with a third type of rim cylinder; Fig. 4 is a rear view of the housi ng only; Fig. 5A is a side view of a first type of shim; Fig. 5B is a plan view of the shim of Figure 5A; Fig. 6 is a plan view of a second type of shim; Fig. 7 is a plan view of a third type of shim; and Fig. 8 shows a section through an actuating mechanism employing the shims of Fig. 6 or Fig. 7. Throughout the specification, the terms front and rear are used. Figs. 1 and 2 show a door 1 in a section alone with an actuating mechanism embodying the present invention. In this drawing the door 1 has a front face 2 and a rear face 3. The convention used is that the front face represents the side from which the key is inserted, while the rear face is the opposite face. Fig. 3 shows an actuating mechanism similar to that shown in section in Figs. 1 and 2, but in exploded view.

The door 1 is provided with a cylindrical recess 4 passing from the front to the back of the door and into which the housing 5 of the mechanism is inserted.

A rear plate 6 is Enserted into a shallow recess 7 in the rear face 3 of the door and coaxial with the cylindrical recess 4. The housing 5 is held in place by a number of screws 40 (see Fig. 3) each of which extends through a hole 8 (only one of which is shown in Figs. 1 & 2) originally along the cylindrical recess, and is screwed into aligned holes 9 (only one of which is shown in Figs. 1 and 2) in the housing 5. For wooden doors, woodscrews 45(see Fig. 3) can also be employed to pass through the rear plate 6 and into the body of the door itself. This provides an additional level of security against the forced removal of the housing S.

The housing 5 has a generally circular front plate 10 from which a hollow cylindrical portion 11 extends rearwardly. The front plate 10 has a bevelled peripheral edge 12 extending radially beyond the cylindrical portion 11 to provide a lip. A peripheral groove 13 extends around the lip to provide a weak region around the periphery of the front plate. Thus, should the lock be attacked by a chisel, it is designed to break preferentially around the rim of the front plate, rather than at any of the screws holding the housing 5 in place.

A through hole 14 is provided in the front plate to allow for the insertion of a key. In the rear face 15 of the front plate 10 there is a circular recess 16 which is concentric with the through hole 14. A circular disc 17 having an elongate through slot 18 is loosely retained in the slot. The disc 17 is rotatable to provide additional protection against drilling the lock and is, in preference, formed from a hard material such as manganese steel, although a laminar structure may be employed instead.

A cylinder 20A7, 20B, 20C is retained within the housing by a rear plate 21 which is screwed to the housing by a pair of screws 50 (Fig. 3) which engage with screw holes 22 in the housing 5.

The cylinder 20A shown in Fig. 1 is deep enough (i.e. has a dimension in the direction in which the key is inserted) to extend for most of the distance between the rear face 15 of the front plate 10 and the plate 21. Because of this, a single shim 30 is inserted between the cylinder 20A and plate 21 so that, when the plate 21 is screwed in place, the cylinder is tightly clamped against the rear face 15.

A first type of shim is shown in greater detail in Figs. 5A and 5B. The shim has a generally disc like configuration with a circular periphery from which a small tab 31 extends. An eccentric oval shape hole 32 is punched through or otherwise formed in the shim. When the shims are in position, the tab 31 fits into a corresponding recess 33 in the inner wall of the cylindrical portion 5 so as to enable the shim to be fitted in place in the correct orientation with a hole 32 in the correct alignment. The rearwardly extending portion 34 of the cylinder 20A, 20B projects through the hole 32 in the shim. It will be appreciated from this that, because in this embodiment the hole 32 has an oval shape, it can accommodate cylinders in which the rearwardly extending portion 34 is at different locations which respect to the main body of the cylinder. A tang 35 which is connected to the barrel (not shown) of the cylinder projects rearwardly from the cylinder and engages with a bolt actuator (typically mounted on the rear of the door)(not shown), in a conventional manner.

The cylinder 20B shown in Fig. 2 and the cylinder

200 shown in Fig. 3 each have less axial depth than the cylinder 20A of Fig. 1, so that three shims 30, 30A are required respectively. As can best be seen from Fig. 2, all of the shims have the same thickness. It is possible to manufacture shims having a range of thicknesses in order to accommodate a range of different cylinder depths. However, as can be seen from Fig. 1, the same effect can be obtained by leaving a clearance 36 between the rear face of the cylindrical portion 11 and the plate 21 giving the advantage that only a single thickness of shim needs to be produced.

It will be appreciated from the foregoing and from Figs. 1, 2 and 3 in particular that the cylinder 20A, 20B or 20C "floats" within the housing 5 and it is the effect of compression or sandwiching of the cylinder between the rear face 15 of the front of the plate 10 of the housing and the rear plate 21 which prevents rotation of the cylinder 20 relative to the housing 5. The shims 30 are, of course, prevented from rotating relative to the housing 5 by means of the tab 31. It has been found that, although this arrangement is successful in preventing rotation of the cylinder, under extreme duress some rotation can still occur. To address this, a modified arrangement such as is shown in section in Figure 8 is employed. Here, the rear of the cylinder 20 is provided with threaded holes 65 which are generally parallel with the central axis of the cylinder but are radially offset therefrom. Socket set screws 55 are screwed into these threaded holes 65 and the heads thereof protrude rearwardly of the cylinder. The heads of the socket set screws 55 engage with the edges of corresponding holes or slots in the shims 30 and rotation of the cylinder relative to the shim or shims is thereby prevented. Since the shim 30 is in turn

prevented from rotating relative to the housing 5 by virtue of the tab 31, the whole mechanism is largely prevented from rotation and hence damage even under significant duress.

The shims may take a number of different forms. In Figs. 3 and 6, the shims are illustrated with two holes 60 which are separate from the hole 32A which receives the tang 35. In Figure 7, by contrast, the hole in the shim to receive the tang 35 and the holes to receive the heads of the socket set screws 55 are formed as a single aperture with ears 70.

It will be seen also from Fig. 8 that the head of each socket set screw 55 does not need to extend through each of the shims 30A, 30B and instead may extend through one or only some of the shims where multiple shims are employed.

Claims

CLAIMS 1. An actuating mechanism for a surface mounted lock comprising: a housing having a front plate for abutment with a face of a door, and a hollow cylindrical portion extending rearwardly from the front plate; a cylinder insertable through the rear of the housing and fixed within the housing; a barrel rotatably mounted within the cylinder, arranged to receive, in use, a key through the front plate, and being arranged, in use, to operate a bolt actuator of a surface mounted lock on the rear face of the door; wherein the cylinder is sandwiched in the housing between the rear face of the front plate and a rear plate mounted to the rear of the cylindrical portion of the housing with at least one shim between the rear of the cylinder and the plate, the or each shim or the plate having an opening in which the cylinder is received to prevent it moving transversely to the direction of the axis about which the barrel is rotated. 2. A mechanism according to claim 1, wherein the cylinder is a rim cylinder having a tang which projects rearwardly from the rear end of the barrel. 3. A mechanism according to claim 1 or claim 2, wherein the opening has an oval shape. 4. A mechanism according to any one of the preceding claims, wherein the opening is provided in the or each shim. S. A mechanism according to claim 4, wherein each shim has a non-circular external shape which fits closely with at least a part of the circumference of the internal face of the cylindrical portion which is

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correspondingly shaped. 6. A mechanism as claimed in claim 5, in which the or each shim includes an outwardly facing, radially projecting lug arranged in use to be received by a corresponding axially extending slot formed in the internal face of the cylindrical portion of the housing. 7. A mechanism according to any one of the preceding claims, in which the or each shim together form a packing member whose axial length is substantially the same as or greater than the distance between the rear of the cylinder when inserted into the housing and the rear of the cylindrical portion of the housing to which the rear plate is mounted, such that the cylinder is firmly clamped to prevent axial rotation thereof when the rear plate is mounted. 8. A mechanism according to any one of the preceding claims, wherein a disc with a through slot is rotatably retained between the front face of the cylinder and the rear face of the front plate to overlie a key slot in the front of the barrel, whereby when the disc is in a certain rotational orientation, access to the key slot is available through the slot. 9. A mechanism according to any one of the preceding claims, wherein the front plate projects radially outwardly of the hollow cylindrical portion to define a peripheral lip, and a recess is provided in a rear facing surface of the lip around its circumference. 9. A mechanism as claimed in claim 8, in which the disc is formed from manganese. 10. A mechanism according to any one of the preceding

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claims, wherein the, front plate projects radially outwardly of the hollow cylindrical portion to define a peripheral lip, and a recess is provided in a rear facing surface of the lip around its circumference. 11. R mechanism as claimed in any one of the preceding claims, further comprising a peg extending along a direction generally parallel with, but radially displaced from, the axis about which the barrel is located, the peg engaging the cylinder and the or at least one of the shims so as substantially to prevent relative rotation therebetween. 12. R mechanism as claimed in claim 11, in which the peg comprises a socket set screw threaded into the said cylinder, the head of the set screw extending in use away from the cylinder so as to engage the or the at least one shim. 13. A mechanism as claimed in claim 12, wherein the or at least one of the shims further includes an aperture whose dimensions are large enough to allow the said set screw head to pass through it but small enough that any relative movement between the cylinder and the, or the at least one, shim causes the set screw head to engage with the walls of the aperture and thus prevents further relative rotational movement. 14. In combination, the mechanism of any preceding claim, a mounting plate, and a door, the mechanism being externally shaped so as to be insertable in a cylindrical recess in the door, the mechanism in use, being held in place within the said cylindrical recess in the door by fixing means passing from the mounting plate, located on a first face of the door, and into engagement with the housing of the mechanism such that

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the front face theveof abuts with a second, opposite face of the door. 15. The combination of claim 14, further comprising a lock mechanism on the said first face of the door, the lock mechanism being actuatable by insertion of the key through the said front plate of the mechanism housing. 16. An actuating mechanism substantially as herein described with reference to the accompanying drawings.