GB2515729A

GB2515729A - Improvements to cylinder locks with thumb-turns

Info

Publication number: GB2515729A
Application number: GB1309863.7A
Authority: GB
Inventors: David Jennings
Original assignee: UAP Ltd
Current assignee: UAP Ltd
Priority date: 2013-06-03
Filing date: 2013-06-03
Publication date: 2015-01-07
Also published as: GB201309863D0

Abstract

A cylinder lock comprises a casing within which is rotatably mounted a core 7 for operating a latching mechanism, and a thumb-turn 11. The thumb-turn is axially movable longitudinally towards and away from the casing between first and second positions. A biasing means 12 such as a spring biases the thumb-turn into its first position in which it is disengaged from the core such that rotation of the thumb-turn is not transmitted to the core. The thumb-turn is movable against the bias into a second position wherein it engages the core 7 so that rotation of the thumb-turn rotates the core 7. Thumb-turn 11 may have a hollow extension 8 with protrusions/castellations 13b that intermesh with protrusion 13a on core 7 which may also include a hollow portion. A bolt 14 with a shoulder 16 may be connected to the core 7 and slidably received with the thumb-turn extension 8 to retain the thumb-turn.

Description

IMPROVEMENTS TO CYLINDER LOCKS WITH THUMB-TURNS

The present invention relates to cylinder locks to with a tumb-turn on one side.

Cylinder locks are used in conjunction with a mortise ock case comprising a latching mechanism for locking doors, windows and other closures. The cylinder lock typically comprises a locking mechanism that operates a rotatable cam that, when rotated, bears against a spring-loaded portion of the latching mechanism to open it. Such locks may comprise single cylinder locks that allowing locking of a closures from one side only but usually the cylinder lock is a douMe cylinder that extends through the closure and is adapted so that it can be operated from both sides, at least one of the sides being key-operated with the other side being either key-operated or having a thumb-turn. The cam is therefore positioned approximately mid-way along the cylinder of the lock and is selectively connected to locking mechanisms on both sides that are either operated by keys or, in the case of thumb-turns, by turning a knob or lever. The connection between the locking mechanism and the cam is effected by a clutch that is axially slidable along the cylinder between two positions wherein it is engaged by one of the lock mechanisms and turns the cam as the key or thumb-turn is rotated but is not engaged by the other of the lock mechanisms so that it can rotate freely relative thereto. In cylinder locks wherein both sides are key-operated, a key inserted fully into one side of the lock acts on the clutch to move it into the position wherein it engages the locking mechanism into which the key has been inserted. However, in cylinder locks with a thumb-turn, the clutch is usually biased into the position wherein it is normally engaged with the thumb-turn so that a user can open the closure by simply rotating the thumb-turn but can be slid into the other of the two positions by a key inserted into the other side of the lock.

A problem with known locks of this type that have a thumb-turn is that they are susceptible to be readily opened by an intruder if the intruder can gain access to the thumb-turn. Usually, the intruder does this via a letter-plate, which provides a convenient opening through the closure that is often located close to the lock. If the intruder can gain access to the thumb-turn via the letter-plate and pass a band or cord around the thumb-turn, it is often possible to rotate thumb-turn by manipulation of the cord or band to thereby open the lock without causing any damage to the lock or the closure.

Such a method of opening the lock is quick and silent.

The object of the present invention is to provide a cylinder lock with a thumb-turn that will thwart such attempts to open the lock by simple rotation of the thumb-turn.

According to the present invention there is provided a cylinder lock for a closure comprising a casing; a core rotatably mounted within the casing that is adapted. on rotation, to actuate means for operating a latching mechanism located adjacent the lock; a thumb-turn that is movable longitudinally towards and away from the casing between first and second positions; and a biasing means that biases the thumb-turn into its first position; the thumb-turn being movable against the force of the biasing means into its second position wherein it engages with the core so that on rotation by turning of the thumb-turn the core is also rotated to actuate said means for operating the latching mechanism but when in its first position it is disengaged from the core so as to be rotatable independently of the core.

Preferably, the thumb-turn comprises a projection that projects into the casing and is inter-engageable with the core.

Preferably also, the core and the thumb-turn are at least partially hollow and the biasing means is ocated within the hollow portion of the core and/or the thumb-turn. Advantageously, the hoflow portion of the thumb-turn is the projection.

Preferably also, a bolt is located within the hollow portions of the thumb-turn and the core, the bolt being secured to one of them and slidable within the hollow portion of the other of them when the thumb-turn moves between its first and second positions. The bolt connects the thumb-turn to the core while permitting it to move between its first and second positions.

Preferably also, adjacent portions of the thumb-turn and the core define intermeshing formations that are inter-engaged when the thumb-turn is in its second position and that are disengaged when the thumb-turn is in its first position.

Other preferred but non-essential features of the present invention are described in the dependent claims appended hereto.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which:-Fig. I is a side view of a cylinder lock in accordance with the present invention with a thumb-turn of the lock being located in a first position relative to the rest of the lock but with parts of latching and locking mechanisms not relevant to this invention omitted; Fig. 2 is a perspective, longitudinal sectional view of the lock shown in Fig. I, a thumb-turn and associated parts of the lock being ocated in a second position relative to the rest of the lock; Fig. 3 is a view similar to Fig. 2 but with a lock casing omitted and showing the thumb turn and associated parts of the lock in their first position; and Fig. 4 is an exploded perspective view of the parts of the ock shown in Fig. 3.

An embodiment of cyfinder lock I in accordance with the present invention comprises an outer casing 2 that is adapted to extend through a closure such as a door. The casing 2 has exterior and interior portions and 4 respectively, which are connected by an integral central joining portion 5.

In practice, a cam assembly (not shown) is located adjacent the joining portion 5 in the gap between the exterior and interior portions 3 and 4 so that it can be actuated by one or other of the mechanisms contained within these portions 3 and 4 of the lock casing 2. The cam assembly is itself adapted to operate a atching mechanism for the closure which is usually located adjacent the casing 3 of the lock 1 within the closure. The mechanism within the exterior portion 3 of the ock I is usually a key-operated locking mechanism whereas the mechanism within the interior portion 4 maybe a thumb-turn arrangement in accordance with the present invention as is described below. However, as details of the cam mechanism, the locking mechanism in the exterior portion 3 of the casing 2 and the latching mechanism are not relevant to the present invention, they are not shown in the drawings and will not be further described.

Within the interior portion 4 of the casing 2 are a rotatably-mounted, hollow core 7 and a projection 8 that forms part of a thumb-turn 11. The projection 8 projects into the casing 2 and is inter-engageaMe with the core 7. The core 7 comprises a hollow cylinder that is located within the casing 2 and that is adapted at its end 9 opposite the projection 8 to engage and thereby actuate a cam mechanism or similar located adjacent the joining portion 5 of the casing. The projection 8 is also in the form of a hollow cylinder and is secured via a pin M to the rest of the thumb-turn 11, which comprises a head shaped to facilitate manual gripping and turning. However, it will be appreciated that the projection 8 and the rest of the thumb-turn 11 could be integrally formed or otherwise connected together. The projection 8 is movable longitudinally within the casing as the thumb-turn 11 moves longitudinally towards and away from the casing between first and second positions. A biasing means 12, as described below, is provided that normally biases the thumb-turn 11 into its first position. When in its first position, as shown in Figs. 1 and 3, the projection 8 is spaced from the core 7 so that when the former is rotated within the casing 2 by turning the thumb-turn 11 it turns independently and has no effect on the core 7, which remains stationary. However, the core 7 and the projection 8 are adapted to inter-engage when the thumb-turn 11 is moved into its second position, as shown in Fig. 2. To this end, adjacent end rims of the core 7 and the projection 8 define intermeshing formations in the form of castellations 13a on the core 7 and castellations 13b on the projection 8. The castellations 13a and 13b mesh with one another when the thumb-turn 11 and thereby the project ion 8 is in its second position so that rotation of projection 8 by rotation of the thumb-turn 11 as a whole also rotates the core 7. This causes the core 7 to actuate the cam mechanism or other adjacent portion of the lock mechanism.

The projection 8 is biased into its first position by the biasing means 12, which in the present example comprises a compression spring located within the hollow portion of the projection 8. The compression spring 12 acts between that part of the thumb-turn 11 which is inserted into and secured to the projection 8 by the pin 10 and a bolt 14 that is partially located within the projection 8 but that is secured to the core 7 by a pin 15. The bolt 14 slides forwards and backwards within the projection 8 as the latter moves between its first and second positions. To prevent the projection 8 from being removable from the casing 2, the bolt 14 defines a shoulder 16 which forms an abutment against a radial flange 17 defined by the projection 8 adjacent the casteflations 13b. This ensures that the projection 8 remains connected to the core 7 when the thumb-turn 11 is biased into its first position by the spring 13.

It will be appreciated that the arrangement of the spring 12 and bolt 14 could be changed, for example by locating the spring in the core 7 on the other side of the bolt 14, to produce the same effect, namely biasing the thumb-turn 11 into its first position. Alternatively, the head of the thumb-turn 11 may be hollow and the spring 12 located within that part of the thumb-turn, the core 7 may then occupy the entire internal portion 4 of the casing 2 and interact with the thumb-turn within the hollow head of the thumb-turn 11. The type of biasing means may also be varied and the shape of the intermeshing formations need not be in the form of castellations 13a and 13b but could comprise any inter-engaging formations or parts that operate to engage and disengage the thumb-turn 11 and the core 7 when they are pushed together or forced apart respectively.

In use, the biasing means 13 biases the thumb-turn 11 into its first position wherein rotation of the thumb-turn 11 has no effect on the core 7so that the lock remains closed. This is the normal position of the lock 1 so that if an intruder attempts to turn the thumb-turn 11 remotely from the exterior of a closure to which the lock Ifs fitted bypassing a cord or band around the thumb-turn 11, the latter will rotate but not open the lock 1. However, when it is desired to open the lock I from the interior of the dosure, a user can do this by pushing the thumb-turn 11 towards the casing 2 against the force of the biasing means 13 to force the projection 8 into engagement with the core 7 and by then turning the thumb-turn 11. When the thumb-turn 11 is turned in this position it rotates the core 7 which then actuates the cam mechanism or similar located adjacent the joining portion 5 of the casing 2 to operate the latching mechanism to open the closure. However, as soon as pressure on the thumb-turn 11 is released it is moved by the biasing means 13 back into its first position so that if it is rotated it no longer causes rotation of the core 7. Hence, a lock according to the present invention will thwart attempts to open the ock by simple rotation of the thumb-turn 11.

Claims

CLAIMS1. A cylinder lock for a closure comprising a casing; a core rotatably mounted within the casing that is adapted, on rotation, to actuate means for operating a latching mechanism located adjacent the lock; a thumb-turn that is movable longitudinally towards and away from the casing between first and second positions; and a biasing means that biases the thumb-turn into its first position, the thumb-turn being movable against the force of the biasing means into its second position wherein it engages with the core so that on rotation by turning of the thumb-turn the core is also rotated to actuate said means for operating the latching mechanism but when in its first position it is disengaged from the core so as to be rotatable independently of the core.
2. A lock as claimed in Claim i, wherein the thumb-turn comprises a projection that projects into the casing and is inter-engageable with the core.
3. A lock as claimed in Claim I or Claim 2, wherein the core and the thumb-turn are at least partially hollow and the biasing means is located with in the hoflow portion of the core and! or the thumb-turn.
4. A lock as claimed in Claim 3 when dependent on Claim 2, wherein the hoflow portion of the thumb-turn is the projection.
5. A lock as daimed in Claim 3 or Claim 4. wherein a bolt is located within the hollow portions of the thumb-turn and the core, the bolt being secured to one of them and slidable within the hollow portion of the other of them when the thumb-turn moves between its first and second positions.
6. A lock as claimed in Claim 5, wherein the bolt is secured to the core and is slidable within the hollow portion of the thumb-turn.
7. A lock as claimed in Claim 5 or Claim 6, wherein the biasing means is located between the bolt and the thumb-turn within the hoflow portion of the thumb-turn.
8. A lock as claimed in any of Claims 5 to 7, wherein the bolt defines a shoulder forming an abutment that retains the thumb-turn connected to the core when the thumb-turn is biased into its first position by the biasing means.
9. A lock as claimed in any of Claims I to 8, wherein adjacent portions of the thumb-turn and the core define intermeshing formations that are inter-engaged when the thumb-turn is in its second position and that are disengaged when the thumb-turn is in its first position.
10. A lock as claimed in Claim 9, wherein the intermeshing formations comprise castellations formed around adjacent rims of the core and the thumb-turn.
11. A lock as claimed in any of Claims 1 to 10, wherein the biasing means comprises a compression spring.
12. A cylinder lock for a closure substantially as described herein with reference to the accompanying drawings.