GB2167112A - Latching and locking mechanisms for doors - Google Patents

Abstract

A latching and locking mechanism having a first latch bolt 19 which is spring urged towards its extended position, and at least one further bolt 31,32 controllable by the same operating handle as is used to control the first latch bolt 19, but by a different action to that used for controlling the first latch bolt 19, and also having locking means 23 which is either separate from the first latch bolt 19 or which locks the bolts. <IMAGE>

Description

SPECIFICATION Latching and locking mechanisms for doors This invention relates to latching and locking mechanisms for use on hinged doors. The invention is primarily, though not exclusively, concerned with locking mechanisms for use on doors used in dwelling houses, as front or back doors.

Conventionally, it is common for the front door of a dwelling house to be lockable from both inside and outside, and for the door to be openable by means of a handle only from the inside. On a back door the arrangement commonly is that the handle can be used to open the door from both inside and outside.

There are, however, a number of other possible arrangements.

Conventionally, the door is latched by means of a bolt which can be withdrawn, usually against spring auction, by operation of a handle and locking is by means of a completely separate door lock. However, in some examples these have been combined and multiple functions are provided.

The latch bolt is usually positioned approximately mid-way of the height of the door but it is also known to provide latches at spaced positions on the door to engage respective keepers or equivalent parts on the frame. These provide additional reg istration for the door so that it fits accurately in its frame and also there is added security. Certain mechanisms provide for simultaneous actuation of more than one latch bolt, by means of a common handle or other device. Such multi-bolt arrange ments are, however, not commonly used on front or back dwelling house doors in which the greatest security may be required.

In the interests of security, dead locking is often used, that is provision of a lock bolt which cannot, when locked, be withdrawn by means of endwise pressure on the bolt. Dead locking may be a feature of a separate lock or means may be provided on a door latch mechanism to prevent the latch bolt from being withdrawn by application of such endwise pressure.

It is the object of this invention to provide a latching and locking mechanism for hinged door which incorporates the advantages afforded by multiple, spaced, bolts, which are all operable from one position, and in which locking is achieved in a secure but conveniently operated manner.

According to the present invention, there is pro vided a latching and locking mechanism including a first latch bolt controllable by an operating member and spring urged into an engaging position, at least one further bolt which is controllable by the same operating member but, in response to an action of that operating member differing from that used to control the first latch bolt and means for locking by means of the bolts and/or by means of a separate lock bolt.

Conveniently, the first latch bolt is retractable by means of the operating member, against spring means, and the or each further bolt is positively operable both to extend it and retract it, by the operating member.

The action of the operating member to control retraction of the first latch bolt may be by angular movement in one direction, whereas the action of the operating member to control extension of the or each further bolt may be by angular movement in the opposite direction.

Preferably angular movement in said one direction serves to retract both the first latch bolt and the or each further bolt, if it is in extended position.

Conveniently, there is a key operable lock controlling separate lock bolt. This may be interconnected with the first latch bolt and/or the or each further bolt to prevent retraction thereof when the lock bolt is in its extended position.

A separate means for dead locking the first latch bolt may advantageously be provided.

Conveniently, the interconnection between the key operable lock and the first latch bolt enables the first latch bolt to be retracted by key operation.

In one form of the mechanism, the operating member is a handle actuatable from one side of a door to which the mechanism is fitted, so that the functions of the operating member are controllable only from said one side.

In an alternative arrangement, the operating member is represented by two handles situated at opposite sides of a door to which the mechanism is fitted and the functions of the operating member are controllable from either side.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of a latching and locking mechanism for doors and constructed in accordance with the invention; Figure 2 is an enlarged perspective view of the central unit of the mechanism; Figure 3 is an enlarged perspective view of an end unit of the mechanism; and Figure 4 is an enlarged perspective view of one type of spindle used in association with the mechanism.

The mechanism illustrated is intended for use on hinged doors and is to be fitted to the stile or vertical edge of the door remote from the hinge. The mechanism is suitable for use on a front or back access door for a dwelling house but it is to be understood that the mechanism can be used in other circumstances where similar latching and locking requirements exist.

The mechanism as shown in Figure 1 includes a central unit (10) which is also shown in Figure 2 and two end units (11 and 12), one of these being shown in Figure 3. These are inter-connected in a manner which will be described and each includes a casing (13, 14, 15), each of which is flanged at its front end.

To each front flange is fitted a forend plate (16, 17, 18) and through the front of the casing and the respective forend plates extend latch or locking bolts to which further reference will be made herein. The purpose of the forend plate is to enclose the fixing screws (not shown) by means of which the casings (13, 14, 15) are secured at the edge of the door and each mechanism unit is contained within a recess cut or formed in the door.

The latch or lock bolts, furthermore, extend into engagement with respective keeper plates (not illustrated) which are fixed to the door frame in conventional manner.

The centre unit (10) has a casing (13) which encloses a mechanism connected to a latch bolt (19) and to an operating bush (21). The bush has a square holethrough which can pass an operating spindle of corresponding square section onto the ends of which are secured in use, handles. The handles are fixed to opposite sides of the door in which the mechanism is fitted and angular movement of one of the handles rotates the bush (21) and this, in turn, through the internal mechanism in the case (13) retracts the latch bolt (19) against the action of a spring so that the bolt is normally extending in the position illustrated in Figures 1 and 2.

internal parts (not shown) limited travel in opposite angular directions from the neutral position of the bush (21) and the spring is normally arranged to return the bush to its neutral position as well as urging the latch bolt (19) outwardly. Adjacent to the latch bolt (19) and also extending through the front ofthe casing and theforend plate (17) is a small snib (22). This is spring loaded and is provided with angled front faces. When the door is closed against the frame, the latch bolt (19) and the snib (22) are driven into the casing by the striker plate. When the keeper opening is reached by the latch bolt (19) this springs into the opening but the snib (22) remains pressed inwardly since there is no corresponding opening into which it engages.Inward movement of the snib (22)-actuates a part of the internal mechanism in the casing (13) to deadlock the latch bolt (19) thus preventing its retraction into the casing by application of pressure directly onto the latch bolt (19) in an endwise direction. Thus unauthorised attempts to retract the latch bolt by forcing a tool between the door and frame are prevented. However, rotation of the bush (21) overrides the action of the snib and allows the latch bolt (19) to be retracted.

Beside the latch bolt (19) and also extending through the forend plate (16) is a lock bolt (23). in this example, the lock bolt is of rectangular section and includes two hardened steel pins to prevent unauthorised entry by cutting through the bolt. The lock bolt (23) is retractable and extendable through the action of a key operated mechanism (not illustrated) which occupies the keyhole-shaped opening (24) in the casing (13). A tail of the lock bolt (23) is guided in the casing through a guide pin (25) running in a slot (26) in the casing. The key operated lock mechanism may be of several kinds providing, in one example, inward and outward movement of the lock bolt by simple angular movement of the key. Dead locking may be provided and may be achieved through further rotation of the key beyond the position at which the lock bolt extends out ofthe casing.The key operable lock mechanism also has interconnection with the mechanism controlled by the operating bush (21). By means ofthis interconnection, angular movement of the key in one direction corresponding with retraction of the lock bolt (23) also carries out retraction of the latch bolt (19). It is therefore possible, by means of the key, not only to release the lock bolt (23) but also to withdraw the latch bolt (19) to enable the door to be opened.

At opposite ends of the centre unit (10) there are respective drive members (27,28) each of which includes a connecting pin, one of which is shown in Figure 2 at 29. These drive members (27, 28) are guided for movement towards and away from one another in a direction of the length of the unit (10).

Angular movement of the operating bush (21) is a direction opposite to that used to retract the latch bolt (19) effects sliding movement of the drive members (27, 28) away from one another, such movement being simultaneous. Angular movement of the bush in the opposite direction moves the two drive members (27, 28) towards one another. Such angular movements to control sliding movement of the drive members (27, 28) are, however, beyond the range atwhich the bush operates the latch bolt (19).

In a convenient arrangement in an installation on a door the spindle engaged in the bush (21) carries handles at opposite sides of the door and where levertype handles are used, these lie generally horizontal in conventional manner. Downward movement ofthe handle providing angular movement of the bush (21) in one direction produces retraction of the latch bolt (19) and releasing the handle allows itto return to the generally horizontal position in which the latch bolt is again outwardly extending. Upward movement of the handle from the horizontal moves the drive members (27, 28) outwardly and a further spring which may be incorporated in one or both of the handles is used to return the handle to the horizontal.However, such return movement does not return the drive members (27, 28) to their inward position, but this is achieved when downward movement of the handle is again carried out.

The end units (11, 12) comprise casings (14,15) containing retractable bolts (31,32). The internal mechanisms within the casings (14, 15), however, include means whereby the bolts (31,32) are deadlocked when in their extended positions.

Inter-connecting the central unit (10) with the end units (11, 12) are transmission bars (33,34). eT Each transmission bar, as shown in Figure 3, is of rectangular section and is connected to the internal mechanism within the casing (14 or 15). This mechanism includes a guide pin (34) engaged in a slot (35) in the casing to limit lengthwise movement of the transmission bar (33). Rack and pinion, or other mechanism may be used to translate lengthwise movement of the transmission bar (33) into extending and retracting movement of the bolt (31) as seen in Figure 3.

At the end of the transmission bar (33) remote from the casing (14), there is a cut-out (36) into which the pin, forming part of the drive member (27 or 28) is engaged. To retain the pin (29) in the cut-out (36) the transmission bar (33) carries a sliding locking device (37) which can be moved over the cut-out when the pin is engaged.

Openings (38,39) in the flange of the casing (13) of the centre unit provide access for engagement of the transmission bars and actuation of the members (37) during installation.

The arrangement is such that outward movement of the drive members (27 and 28) results in corresponding outward movement of the transmission bars (33,34) and extension of the bolts (31,32) in the end units. These are intended to engage in respective openings in the door frame and to assist alignment and to draw the door closely into engagement with a seal on the frame or otherwise, the forward face of the bolts (31,32) are angled as shown.

In one example, a single spindle is engaged in the bush (21)so that handles fitted to opposite ends thereof can be used to operate the mechanism alternatively.

However, as shown in Figure 4, an alternative type of spindle may be used where relative rotation between the two ends is possible. Such spindle comprises two square section portions (41,42) connected by a rotating connecting part (43). A sleeve (44) surrounds one end portion (42) and is engaged in a groove therein to provide an end limit.

With such a spindle, rotation of the handle at one side of the door only actuates the bush (21), whereas rotation of the handle at the other side does not affect any part of the mechanism. It is customary for such a mechanism to be used on a front door where the outside handle does not operate the mechanism, whereas the internal handle does so.

In use, rotation of the bush (21) by means of the handle at one or other side of the door controls movement of the latch bolt (19) as described. When only that bolt is extended, it is possible to open the door by angular movement in a downward direction of the handle. Closing the door drives the latch bolt (19) inwardly against its spring and this is again extended when it passes the keeper and strike plates. As previously described, the snib (22) provides deadlocking of the latch bolt (19) when engaged againstthe strike plate. Closing of the door can be carried out with or without accompanying downward rotation of the handle.

By moving the handle angularly in an upward direction, through a predetermined angle, the bolts (31,32) are extended into respective openings in the door frame. This provides a secure latching arrangement and the door is held securely and accurately in its frame so that seals are accurately engaged.

To provide additional security, the door can be locked by actuating the key operated mechanism to drive the lock bolt (23) into a corresponding opening in the frame. This action provides further deadlocking of the latch bolt (19) and also of the drive members (27 and 28) and thus, the associated bolts (31,32) in the end units (11 and 12).

The key can be used to retract the lock bolt (23) when unlocking is required and further rotation of the key effects retraction of the latch bolt (19).

Withdrawal of the bolts (31,32) in the end units is effected by angular movement of the handle in a downward direction.

Where a split spindle as in figure 4 is used, the outside handle can release the end unit bolts but cannot release the centre unit latch bolt (19).

It is, however, to be understood that otherfunc- tions can be controlled through different movements of the handle and of the key operated mechanism.

The key operated mechanism may be provided with a control knob replacing the key actuated components so that manual operation of this part of the mechanism can be carried out if required.

In an alternative arrangement, the latch bolt (19) serves also as the lock bolt and a key operated mechanism may be incorporated in the handle at one or both sides.

The latch bolt (19) can be reversed for use on left or right-hand opening doors and the mechanism is suitable for use on doors opening inwards or outwards with a minimum of adjustment. The bolts (31,32) in the end units are capable of being used in either direction of opening of the door.

The end units (11, 12) are preferably positioned neat the upper and lower ends of the door so that the separation of the three units is as great as possible to give maximum security and rigidity to the door. It is possible to use only one end unit. End units may be provided to engage with frame portions above and below the door in place of the arrangement shown in which all three units are positioned along the side of the door remote from the hinge.

The snib (22) can be omitted and other features may be incorporated to provide additional functions.

Claims (11)

1. A latching and locking mechanism including a first latch bolt controllable by an operating member and spring urged into an engaging position, at least one further bolt which is controllable by the same operating member but, in response to an action of that operating member differing from that used to control the first latch bolt and means for locking by means of the bolts and/or by means of a separate lock bolt.

2. A mechanism as claimed in claim 1 in which the first latch bolt is retractable by means of the operating member, against spring means, and the or each further bolt is positively operable, both to extend it and retract it, by the operating member.

3. A mechanism as claimed in claim 1 or claim 2 in which the action of the operating member to control retraction of the first latch bolt is by angular movement in one direction, whereas the action of the operating member to control extension of the or each further bolt is by angular movement in the opposite direction.

4. A mechanism as claimed in claim 3 in which angular movement in said one direction serves to retract both the first latch bolt and the or each further bolt, if in extended position.

5. A mechanism as claimed in any one of the preceding claims including a key operable lock controlling a separate lock bolt.

6. A mechanism as claimed in claim 5 in which the separate lock bolt is interconnected with the first latch bolt and/or the or each further bolt, to prevent retraction thereof when the lock bolt is in its extended position.

7. A mechanism as claimed in any one of claims 1 to 4 including a separate means for dead locking the first latch bolt.

8. A mechanism as claimed in claim 6 in which the interconnection between the key operable lock and the first latch bolt enables the first latch bolt to be retracted by key operation.

9. A mechanism as claimed in any one of the preceding claims in which the operating member is a handle actuatable, in use, from one side only of a door to which the mechanism is fitted.

10. A mechanism as claimed in anyone of claims 1 to 8 in which the operating member is represented by two handles actuable, in use, from opposite sides respectively of a door to which the mechanism is fitted.

11. A latching and locking mechanism substantially as hereinbefore described with reference to and as shown in the accompanying drawings.