GB2340535A

GB2340535A - Locking mechanism

Info

Publication number: GB2340535A
Application number: GB9918450A
Authority: GB
Inventors: Terence James Dolman
Original assignee: Trojan Hardware and Design Ltd
Current assignee: Trojan Hardware and Design Ltd
Priority date: 1998-08-07
Filing date: 1999-08-06
Publication date: 2000-02-23
Anticipated expiration: 2019-08-06
Also published as: GB9918450D0; GB9817133D0; GB2340535B

Abstract

A locking mechanism (1) is disclosed of the kind adapted to lock a closure member (2) to a frame (3), the closure member (2) being movable relative to the frame (3) between an open and a closed position, the locking mechanism (1) being operative with the closure member (2) in the closed position to lock the closure member (2) to the frame (3). The mechanism (1) comprises at least one locking element (12) pivotally mounted with respect to the closure member (2) and adapted to be moved angularly by an operating mechanism between a retracted position in which it is held within the closure member (2) and an operating position in which it projects from the closure member (2) and into a slot in the frame, the locking element (12) having a hook means engaging behind an end of the slot.

Description

2340535 LOCKING MECHANISM This invention relates to a locking mechanism of

the kind adapted to lock a closure member to a frame, the closure member being movable relative to the frame between open and closed positions, and the locking mechanism being operative with the closure member in the closed position to lock the closure member to the frame. The closure member may be a window or a door.

It is often advantageous to provide a locking mechanism which is concealed in use, especially where the frame is a plastics member. For example, one conventional locking mechanism comprises one or more pins provided on the closure member. Each pin projects perpendicular to the frame and parallel to the plane of the closure member, and has a shaft and an enlarged head. The pin is adapted to engage in a keyhole-shape slot in the frame. In use, the pin is first moved out of the closure member to cause the head to pass through the enlarged part of the slot. The pin is then moved in a different plane with the shaft in the reduced part of the slot, so that the head engages behind the reduced part to lock the mechanism. This locking mechanism is suitable where the closure member slides in the frame (such as a patio door) because the pin operates in tension. However, it is not so suitable for pivoted closure members, as the pin is operating in bending and so needs to be relatively thicker. The mechanism also requires considerable accuracy in placing the slots, because of the need to ensure that the pin heads pass through the enlarged slot portions, and a relatively complex operating mechanism to provide t the two different directions of movement of the pin.

According to the present invention, a locking mechanism of the kind set forth comprises at least one locking element pivotally mounted with 2 respect to the closure member and adapted to be moved angularly by an operating mechanism between a retracted position in which it is held within the closure member and an operating position in which it projects from the closure member and into a slot in the frame, the locking element having a hook means engaging behind an end of the slot.

The locking mechanism of the invention requires less accuracy in the placing of the slot, because the hook means can operate with a greater tolerance. Further, because the locking element is only required to move angularly, the operating mechanism for the locking element can be much simpler.

The locking element may be arranged to project perpendicular to the frame and parallel to the closure member for use where the closure member slides. The locking element is then operative in tension. Alternatively, the locking element may project perpendicularly from the closure member, into an inwardly-projecting part of the frame. This is particularly suitable where the closure member is pivotally mounted, as the locking element still operates in tension. As long as it operates in tension, the locking element can be a flat, relatively thin plate. The thin plate can then be accommodated in the inwardly -projecting part of the frame, whereas a pin could not be accommodated.

Preferably the locking mechanism has two locking elements. The elements are preferably movable in opposite directions, with their hook means directed oppositely. Both locking elements can then project into the same slot in the frame, and engage at opposite ends of the slot.

Conveniently the or each locking element is pivoted at one end, and has the hook means at the other end, with the operating mechanism acting at 3 an intermediate point. The operating mechanism preferably comprises a linearly -movable locking lug for each locking element, operated from a handle by any suitable mechanism, such as a rack and pinion. Each locking lug has cam surfaces cooperating with the respective locking element to cause the angular movement of the locking element between the retracted and operating positions.

The locking mechanism comprising the locking elements, locking lugs and operating mechanism is attached to the closure member, and a cover plate completes the assembly. Preferably the mechanism is attached to the closure member by fixing screws, which may also act as the pivot points for the locking elements or fix the locking lugs in position.

The slot in the frame is preferably reinforced by a keep member, which is of metal. This is particularly advantageous where the frame is of plastics material. The keep member conveniently is of L-section, being attached to the frame by one arm, and having the slot in the other arm.

An embodiment of the invention is shown, by way of example only, in the accompanying drawings, in which:

Figure 1 shows a locking mechanism for locking a closure member to a frame, the locking mechanism being in an operating position; Figure 2 shows a top view of a part of the locking mechanism of Figure 1; Figure 3 shows the mechanism of Figure 2 in a retracted position; 4 Figure 4 shows the locking mechanism of Figures 2 and 3 closed by a cover plate; Figure 5 shows an underneath view and a side view of the cover plate of Figure 4; Figure 6 shows a top view and a side view of a locking lug; and Figure 7 shows a section through an operating mechanism for the lug of Figure 5 and an end view of the operating mechanism.

The locking mechanism 1 shown in the drawings is for locking a closure member 2 (see Figure 1) to a frame 3. The closure member 2 is movable relative to the frame 3 between open and closed positions, and the locking mechanism is operative when the closure member 2 is in the closed position shown in Figure 1. The closure member 2 illustrated is a window (only the surround 4 of the glass being shown) pivotally mounted in the frame 3 in such a way that it opens by moving to the right in Figure 1. The frame 3 and the surround 4 are plastics profiles. The frame 3 has a substantially L-shaped cross-section. The longer portion 5 forms the main part of the frame, while the shorter portion 6 is perpendicular to the longer portion 5, and forms a glazing upstand which carries a seal (not shown) against which the window surround 4 engages when in the closed position. The window surround 4 is of substantially T-shaped cross section, whose base 7 engages the glazing upstand 6 when the window is closed. The stem 8 of the T supports the glass on one side 9, and the opposite side 10 faces the portion 5 of the frame 3.

The locking mechanism 1 is mounted on the surround 4, on the side 10 of the T, adjacent the base 7, and is partly received in the profile, in a metal -reinforced recess 11. The locking mechanism 1 is shown in more detail in Figures 2 to 7, and comprises a pair of locking hook elements 12 pivotally mounted on the surround 4 and movable angularly by an operating mechanism 13 between the retracted position of Figure 3 and an operating position (Figures 1 and 2). In the operating position each hook element 12 projects through a slot 14 in the glazing upstand 6 and a hook part 15 engages behind a respective end of the slot 14 to lock the closure member 2 to the frame 3.

The mechanism 1 is closed off by a cover plate 16. It will be appreciated that the hook elements 12 are operating in tension, and so can be relatively flat members, which enables them to lock into the glazing upstand 6. The glazing upstand 6 could not accommodate the normal locking pins, which are larger.

As can be seen in Figures 2 and 3 the hook elements 12 are flat metal plate members arranged oppositely, for opposite angular movement when moved by the operating mechanism 13. Each hook element 12 is mounted on the surround 4 for angular movement by a screw 17 at its inner end 18. The opposite outer end 19 has the hook part 15, while at an intermediate region 20 there are cam surfaces for engagement by the operating mechanism 13.

The operating mechanism 13 comprises a pair of line arly-mov able locking lugs 21, one for each hook element 12, moved by a rack and pinion mechanism 22 (see Figure 7) operated by a handle 23 on the closure member 2. A lug 21 is shown in detail in Figure 6. It is of metal, and of elongate outline, with a first rounded end 24 by which it is attached to the 6 rack and pinion mechanism 22. At its opposing end it has a guide slot 25 for the hook element 12, with cam surfaces 26, 27 cooperating with the cam surfaces on the hook element 12. In the intermediate region there is a longitudinal slot 28, through which passes a screw 29. The screw 29 and slot 28 ensure that the lug 21 moves linearly in response to movement of the rack and pinion mechanism 22.

The rack and pinion mechanism 22 may be of any standard form. The mechanism shown in Figure 7 is a known shoot bolt rack and pinion mechanism 22, where rotation of the handle 23 rotates gear wheels 30, 31, 32, to cause racks 33, 34 to move linearly in opposite directions.

Each rack 33, 34 is attached to an end 24 of a respective lug 21, and moves the lug 21 in both directions, according to the direction of rotation of the handle 21. The details of the mechanism 22 do not need further description. It will however be appreciated that the mechanism 22 is received in the recess 11 in the surround 4.

The locking mechanism 1 is completed by the cover plate 16, shown in detail in Figures 4 and 5. As shown in Figure 5, the cover plate 16 has a profiled undersurface to accommodate the hook elements 12, and to retain the lugs 21. The cover plate 16 encloses the mechanism 1 in its retracted position with the exception of the ends 24 of the lugs 21. The cover plate 16 is secured to the surround 4 by the screws 17, 29 which also serve to attach the hook element 12 and lugs 21 to the closure member 2. The screws 29 are received in the reinforced recess 11, while the screws 17 are received in a further recess 35 in the surround 4.

In order to reinforce the slot 14 in the glazing upstand 6, the frame 3 is provided with a keep member 36. The keep member 36 is an angle- 7 section metal component. One arm 37 is secured to the frame part 5 by any suitable means (not shown) while the other arm 38 engages the glazing upstand 6 and has a longitudinal slot 39 corresponding to the slot 14 in the upstand 6. In fact the slot 14 is longer than the slot 39, so that the hook part 15 engages behind the end of the slot 39, rather than the end of the slot 14. This advantageous, as the metal keep member 36 is stronger than the plastics frame 3.

The hook elements 12 are normally in the retracted position shown in Figure 3, in which the whole locking mechanism 1 is held substantially within the surround 4. The window can then move freely between its open and closed positions. To lock the closure member 2 to the frame 3 in its closed position, the handle 23 is rotated, causing the mechanism 22 to move the lugs 21 apart. This in turn rotates the hook elements 12 about the screws 17, and the lugs 21 drag the hook elements 12 into the operating position shown in Figures 1 and 2. As they pivot, the ends 19 of the hook elements 12 project into the slot 39, and then the hook parts 15 engage behind the ends of the slot 39, to lock the surround 4 to the frame 3. Rotation of the handle 23 in the opposite direction returns the lugs 21 to their original position and drags the hook elements 12 back into their retracted position.

The main advantage of the locking mechanism 1 in comparison with the conventional pin mechanisms is that it is simpler to operate. Further, because the hook element 12 locks into the glazing upstand 6, it can be used for pivoting closure members 2, and still operate in tension.

Of course, it would be possible to arrange the hook elements to lock into the portion 5 of the frame 2 in the conventional way, for example where the closure member 2 slides relative to the frame 3.

8 It will also be appreciated that the mechanism 1 requires less accuracy in the placing of the slot 39, because the hook part 15 can operate with a greater tolerance than the conventional pin mechanism.

Claims

9 CLAIMS

1. A locking mechanism of the kind set forth which comprises at least one locking element pivotally mounted with respect to the closure member and adapted to be moved angularly by an operating mechanism between a retracted position in which it is held within the closure member and an operating position in which it projects from the closure member and into a slot in the frame, the locking element having a hook means engaging behind an end of the slot.

2. A locking mechanism according to claim 1, in which the locking element is arranged to project perpendicular to the frame and parallel to the closure member for use where the closure member slides.

3. A locking mechanism according to claim 1, in which the locking element projects perpendicularly from the closure member, into an inwardly projecting part of the frame.

4. -A locking mechanism according to any preceding claim, in which 20 two locking elements are provided.

5. A locking mechanism according to claim 4, in which the two elements are movable in opposite directions, with their hook means directed oppositely.

6. A locking mechanism according to claim 5, in which both locking elements project into the same slot in the frame, and engage at opposite ends of the slot.

7. A locking mechanism according to any preceding claim, in which the or each locking element is pivoted at one end, and has the hook means at the other end, with the operating mechanism acting at an intermediate point.

8. A locking mechanism according to any preceding claim, in which the operating mechanism comprises a linearly-mov able locking lug for each locking element, operated from a handle by any suitable mechanism, such as a rack and pinion.

9. A locking mechanism according to claim 8, in which each locking lug has cam surfaces co-operating with the respective locking element to cause the angular movement of the locking element between the retracted and operating positions.

10. In combination, a locking mechanism according to any preceding claim and a closure member to which the locking mechanism is attached.

11. The combination of claim 10, in which the mechanism is attached to the closure member by fixing screws, which also act as the pivot points for the locking elements or fix the locking lugs in position.

12. A locking mechanism substantially as described herein with reference to the accompanying drawings.