GB2318382A

GB2318382A - Anti-slam mechanism for shoot bolt lock

Info

Publication number: GB2318382A
Application number: GB9619034A
Authority: GB
Inventors: John Rogers
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-09-12
Filing date: 1996-09-12
Publication date: 1998-04-22
Anticipated expiration: 2016-09-12
Also published as: GB9619034D0; GB2318382B

Abstract

An anti-slam mechanism for a door lock comprises a spring loaded 7 probe 6 which extends from the front surface 14 of the lock. In this position the top 17 of the probe 6 bears against a locking face 16 of the locking mechanism and prevents lock actuation. When the probe 6 is depressed by the door keep (18, Fig 2), the locking mechanism can be actuated and the probe 6 moves up into the lock body (Fig 3) as the top slide 2 extends. In the locked position the probe 6 is held inside the lock, which can help facilitate lock installation.

Description

LOCK MECHANISM This invention relates to a mechanism for use primarily, although not exclusively, within locking systems designed for securing sliding doors and windows.

Typically, locks designed to secure sliding doors and windows, are usually mounted into the leading edge of the door or window and feature locking members of various descriptions. The locking member(s) usually moves between an unlocked position and a locked position in response to the user either operating a lever or turning a key. This action causes the said locking member(s) to engage with a component(s) fixed to the door frame commonly known as a 'keep'. In this state the door is secured. One potential hazard with systems of this type is that it is possible to operate the mechanism with the door slid back into the open position such that if the door is subsequently slid into the closed position, with the locking member(s) in the locked out position, a collision with the keep will occur and may potentially damage either or both components. A known method to guard against this is the 'anti-slam' mechanism. This is a mechanism built into the main lock body and features a spring loaded probe which projects from the front face of the lock acting in the sliding plane of the door. This probe is designed to be long enough such that when the door is slid into the closed position it makes contact with the keep marginally before the door is fillly closed, to the degree that the probe is depressed into the lock body when the door has reached it's closed position. The anti-slam mechanism works by interacting with the main locking mechanism of the lock such that the freedom of movement of the locking mechanism is controlled by the position of the probe and hence the proximity of the keep.

With the lock in its unlocked state and with the probe in its extended position (i.e. door open), the locking mechanism is restrained from movement. With the lock in its unlocked state and with the probe in its depressed position (i.e. door closed), the locking mechanism is free to operate. This therefore makes it impossible for the user to inadvertently change the state of the lock from unlocked to locked while the door is in an open position but allows this action when the door is closed.

None of the foregoing is new and is technology which is commonly used and well known to the industry.

One main drawback with a lock of this type and featuring an anti-slam probe, is that in order to be effective it needs to project from the front face of the lock beyond the plane of the outermost component (excluding locking members). The majority of commercially available sliding doors and windows are manufactured from pvcU or Aluminium extruded hollow sections. For reasons of cost and appearance these sections are designed of minimum size. For reasons of strength and security it is preferable that locks are fitted by feeding them into the end of the section and sliding them into a position which is approximately half way along the section. Where this is possible the amount of material removal from the section in preparation for the lock can be significantly reduced and the strength and integrity of the fitting is thereby enhanced. Locking members can hamper this but usually can be removed and refitted after installation. Clearly a probe, which cannot be removed, even if depressed against spring pressure, will hamper such an installation method. There are usually several holes in the leading face of the hollow section into which the lock is to be fitted. If therefore, the lock is fed into the section with the probe depressed, it will repeatedly become snagged every time the probe encounters a hole. This is usually enough to frustrate the fitting process to a degree where a less strong method of installation is adopted.

A means of temporarily restraining the probe in the withdrawn position would overcome these difficulties provided that it is achieved in such a way that once the lock has been installed, the means did not reduce the effectiveness and purpose of the anti-slam mechanism itself.

According to the present invention there is provided an anti-slam mechanism with hold back facility for a sliding door / window lock, comprising a spring loaded probe which projects from the front face of the lock, a means of restraining movement of the locking mechanism until the probe is depressed, and a means of temporarily securing the probe in the withdrawn position to facilitate lock installation.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows an internal view of the lock with the lock unlocked, restrained from movement due to the probe being extended (i.e. door open).

Figure 2 shows an internal view of the lock with the lock unlocked, free to move due to the probe being depressed by the keep (i.e. door closed).

Figure 3 shows an internal view of the lock with the probe restrained in the withdrawn position (i.e. installation position).

This embodiment of the invention as shown in figures 1 to 3 shows the hold back feature as an integral part of the anti-slam mechanism.

Referring to the drawings, the main locking mechanism of the lock is operated by turning the gear 1 through a clockwise angular movement (usually driven by an external lever handle - not shown). The gear 1 is engaged to and therefore drives the top slide 2 upwards and the bottom slide 3 downwards. Fitted into the top slide 2 is the top locking member 4 and likewise fitted to the bottom slide 3 is the bottom locking member 5. This describes the locking motion.

The arrangement in Figure 1 shows the lock in its unlocked and restrained state. The probe 6 is in its extended position under the influence of the compression spring 7 which locates in the bottom of a core hole 8 at one end (inside the probe 6 ) and bears against a fixed post 9 at the other end. The fixed post 9 is secured at each end to the lock body (not shown) and passes through an elongated slot 10 in the side of the probe 6. This arrangement captivates both probe 6 and spring 7 to give controlled, limited movement of the probe with spring pressure.

The probe 6 is also drawn in end view 6a to show a profile change in section from circular to rectangular at the shoulder 11. The portion of the probe 6 which projects through the front face of the lockl4 is circular and the remainder is rectangular and wider in size. The bottom slide 3 features a shaped hollow cavity made up of a front part 12 and a rear part 13 the shapes and profiles of which are shown with dashed (hidden) lines. The front part cavity 12 is sufficiently wide to permit the circular portion of the probe 6 to pass through it but not the rectangular portion of probe 6. The rear part cavity is sufficiently wide to house the rectangular portion of probe 6. Due to this the shoulder 11 of the probe 6, under the influence of the spring 7 bears against cavity face 15 of the bottom slide 3. In this state any attempt the operate the locking mechanism by applying a torque to the gear 1 as described above will be prevented due to interference between the cavity locking face 16 ofthe bottom slide 3 and the top of the rectangular portion 17 of the probe 6.

Figure 2 shows the same configuration as figure 1 except that the keep 18 (shown shaded) is drawn in a position which represents its proximity when the door is closed. The probe 6 is now depressed compressing spring 7 such that the shoulder 11 of probe 6 no longer bears against cavity face 15 of the bottom slide 3. Shoulder 11 has travelled far enough to pass the release point 19 and therefore in this state the cavity locking face 16 of the bottom slide 3 in no longer restrained by the top of the rectangular portion 17 of the probe 6. In this arrangement, the probe 6 does not have to be fully depressed before the slide 3 can begin to travel it only has to have travelled sufficiently to clear the release point 19. Ramp 20 provides a driving surface to fully withdraw the probe 6 to its innermost depressed state to cater for the eventuality that keep 18 does not fully depress probe 6. This therefore allows a degree of fitting tolerance.

Figure 3 shows the gear 1 having been rotated clockwise until the top slide 2 has extended fully upwards and the bottom slide 3 has extended fully downwards. This is the lock in its locked state. In this position the probe 6 is fully depressed and no longer held back by the keep (not shown). The shoulder 11 of the probe 6 is now bearing against the hold back face 21 inside the cavity 13 of the bottom slide 3. In this state the probe 6 no longer has a function of anti-slam because the locking mechanism has already been locked Because the probe 6 is now held back by face 21 the lock is in a suitable condition for easy installation.

Unlocking of the mechanism by reversing the procedure will automatically allow the probe 6 to resume its anti-slam function.

Claims

1. An anti-slam mechanism with hold back facility for a sliding door / window lock, comprising a spring loaded probe which projects from the front face of the lock, a means of restraining movement of the locking mechanism until the probe is depressed, and a means of temporarily securing the probe in the withdrawn position to facilitate lock installation.

2. An anti-slam mechanism as claimed in claim 1 where the means of temporarily securing the probe in the withdrawn position is provided as an integral part of the locking mechanism itself such that operation of the mechanism into the locked position automatically holds back the probe.

3. An anti-slam mechanism as claimed in claim 2 where the means of temporarily securing the probe in the withdrawn position is provided by a shoulder on the probe engaging behind a cavity face of the bottom slide.

4. An anti-slam mechanism as claimed in any of the preceding claims where the probe does not have to be fully depressed to release the restraint on the locking mechanism.

5. An anti-slam mechanism as claimed in claim 4 where the initial movement of the probe is, by necessity, caused by interaction with the keep but the final portion of it's movement into the fully depressed state is provided by a ramp.

6. An anti-slam mechanism as claimed in any of the preceding claims which is made from metal or plastics material or a combination of these materials.

7. An anti-slam mechanism substantially as herein described and illustrated in the accompanying drawings figures 1, 2, and 3.