GB2210923A

GB2210923A - Door latch

Info

Publication number: GB2210923A
Application number: GB8724098A
Authority: GB
Inventors: Ho Kwok Sum
Original assignee: SAFETY GUARD HARDWARE Co
Current assignee: SAFETY GUARD HARDWARE Co
Priority date: 1987-10-14
Filing date: 1987-10-14
Publication date: 1989-06-21
Also published as: GB8724098D0

Abstract

The latch has a handle 21 for rotating a shaft 19 and a curved blade 20 to cause sliding of a first member 7 which retracts a bolt 8 into a housing 1. The curved blade 20 may act directly on the first member 7, thus giving a distance (L1, Figure 1) between the centre line of shaft 19/blade 20 and an end face 21 or the curved blade 20 may act indirectly on the first member via a removable adaptor piece 30 (see Figure 4). In the latter case, the centre line is positioned closer to the end face 2' thereby reducing the distance from L1 to L2. Thus, when the door latch is being fitted to a door, the spacing between the centre line and the side face of the door may be chosen to be either one of two different values (L1 or L2). The adaptor piece 30 has a pair of recesses (31, Figure 5) which locate the adaptor piece 30 through engagement with bosses 40 and shaft 19 and blade 20 project through a central opening 32 in the adaptor piece. <IMAGE>

Description

PESCRIPTION DESCRIPTION DOOR LATCH This invention relates to a door latch which is adjustable to permit, at the time of fitting in the door, the spacing between the handle and the edge of the door to be varied.

According to the present invention, a door latch comprises a bolt slidably mounted in a housing, a first member slidable within the housing to retract the bolt into the housing and bolt control means arranged to act selectably directly on the first member or indirectly via an adaptor piece and operable to slide the first member to cause retraction of the bolt, the adaptor piece being removably mountable on the first member and the arrangement being such that use of the adaptor piece alters the relative positioning of the bolt control means and the housing.

Usually, the alteration of the relative positioning of the bolt control means and the housing is along the direction of sliding of the first member.

The bolt control means may comprise a body and a bolt control mechanism rotatable relatively to the body, the body being rigidly connectable to the housing selectively in two positions spaced apart along the direction of sliding of the first member, one of the positions being for when the bolt control mechanism is arranged to act directly on the first member and the other one of the positions being for when the bolt control mechanism is arranged to act indirectly on the first member via the adaptor piece.

An example of a door latch constructed in accordance with the present invention will now be described with reference to the accompanying informal drawings, in which: Figure 1 is a plan view of the door lock without an adaptor piece; Figure 2 is a section on the line II-II of Figure 1; Figure 3 is a plan view of the door latch with the adaptor piece; Figure 4 is a section along the line IV-IV of Figure 3; and, Figure 5 is a plan view of the adaptor piece of Figures 3 and 4.

Referring to Figures 1 and 2, the door latch comprises a housing 1 formed as a cylindrical portion 2 from the back of which projects a U-shaped frame 3 having a pair of parallel side plates 4, 4' which are joined by an end plate 5.

In a gap 6 between the side plates 4, 4' is located a first member 7 that is operatively connected to a bolt 8 slidably mounted in the cylindrical portion 2. The arrangement is such that the member 7 is free to slide in the direction X to thereby cause retraction of the bolt 8 into the housing 2. The member 7 comprises a pair of arms 7', 7" that ride on either side of a guide 9 that projects upwards from the side plate 4. Each arm 7', 7" is formed with a respective surface 10', 10" that faces towards the bolt 8.

The side plates 4, 4" each have a large central aperture 11 formed therein, together with a series of location surfaces in the form of holes or guide surfaces 12, 13, 14, 15.

The latch also comprises a bolt control means 16 comprising a body 17 and a bolt control mechanism 18 in the form of a central shaft 19 partially surrounded by a curved blade 20, both of which are rotatable by a handle 21. The shaft 19 and curved blade 20 project through the aperture 11 formed in the side plate 4', through the gap between the arms 7', 7" of the first member 7 and then through the aperture 11 of the other side plate 4. The body 17 of the bolt control means 16 also has a pair of parallel projecting arms 22, the spacing between which matches the spacing between the holes 12 and 14 and between the hole 13 and the guide surface 15.By selecting to locate the body 17 relatively to the housing 1 by locating the arms 22 with the location surfaces 13 and 15, side faces 20' of the curved blade 20 are positioned immediately adjacent to the faces 10', 10" of the first member 7. Thus, by turning the handle 21, the curved blade 20 rotates and moves one of its side faces 20' in the direction X to thereby also move the first member 7 in that direction, whereupon the bolt 8 is retracted into the cylindrical portion 2.

It is to be noted that the spacing between the centre line of the shaft 19/curved blade 20 and an end face 2' of the cylindrical portion 2 is a distance L1. When fitted to a door, the distance L1 would be the distance between the centre line of the shaft 19/curved blade 20 and the side of the door, by virtue of the usual convention of having the end face 2' flush with the side of the door.

Figures 3, 4 and 5 show how this spacing may be reduced. Like components have the same reference numerals as in Figures 1 and 2. The only additional component is an adaptor piece 30 (shown in isolation in Figure 5). This adaptor piece 30 is generally annular in shape and has a pair of recesses 31 which locate the adaptor piece 30 relatively to the first member 7 through engagement with bosses 40 that project from the member 7. Movement of the adaptor piece 30 towards the bolt 8 is limited by a stop 41 that projects into the gap 6 from the side plate 4'.

A central opening 32 in the adaptor piece 30 has a pair of surfaces 33 and 34 which face towards the bolt 8. As may be seen from Figure 3, the adaptor piece 30 lies between side plate 4' and first member 7. The shaft 19 and curved blade 20 project through the side plates 4, 4' and the first member 7 in the usual manner but they additionally also project through the central opening 32 in the adaptor piece 30. If the arms 22 of the body 17 are arranged to be located relatively to the housing 1 by the location surfaces 12, 14, then the side faces 20' of the curved blade 20 will be located immediately adjacent to the surfaces 33, 34 of the adaptor piece 30.

Thus, upon turning the handle 21, the curved blade 20 rotates and the adaptor piece 30 is propelled in the direction X and, by virtue of the engagement of the bosses 40 in the recesses 31, the first member is also moved in the direction X, thereby retracting the bolt 8. As a consequence of the arms 22 being located by the location surfaces 12 and 14, the separation between the centre line of the shaft 19/curved blade 20 and the end face 2' of the cylindrical portion 2 is reduced to L2. The size of the reduction from the distance L1 is equal to the offset (e.g 1cam) between the surfaces 12 and 13 (or between the surfaces 14 and 15).

Thus, a craftsman upon mounting the door latch in a door is able to select between distances L1 and L2 for the size of the desired separation between the centre line of the door handle 21 and the side face of the door.

Claims

1. A door latch comprising a bolt slidably mounted in a housing, a first member slidable within the housing to retract the bolt into the housing and bolt control means arranged to act selectably directly on the first member or indirectly via an adaptor piece and operable to slide the first member to cause retraction of the bolt, the adaptor piece being removably mountable on the first member and the arrangement being such that use of the adaptor piece alters the relative positioning of the bolt control means and the housing.

2. A door latch substantially as described with reference to the accompanying drawings.

2. The door latch according to claim 1, in which the alteration of the relative positioning of the bolt control means and the housing is along the direction of sliding of the first member.

3. The door latch according to claim 2, in which the bolt control means comprises a body and a bolt control mechanism rotatable relatively to the body, the body being rigidly connectable to the housing selectively in two positions spaced apart along the direction of sliding of the first member, one of the positions being for when the bolt control mechanism is arranged to act directly on the first member and the other one of the positions being for when the bolt control mechanism is arranged to act indirectly on the first member via the adaptor piece.

4. A door latch substantially as described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A door latch comprising a housing having a frame rigidly attached to a portion containing a bolt slidably mounted therein; a first member slidable within the frame to retract the bolt into the portion; and bolt control means arranged to act selectably directly on the first member or indirectly via an adaptor piece and operable to slide the first member to cause retraction of the bolt, the adaptor piece being removably mountable on the first member and the bolt control means comprising a body and a bolt control mechanism rotatable relatively to the body, the body being connectable to the frame selectively in two positions spaced apart along the direction of sliding of the first member, one of the positions having the body located relatively to the frame by first location surfaces formed in the frame and also being for when the bolt control mechanism is arranged to act directly on the first member, and the other one of the positions having the body located relatively to the frame by second location surfaces formed in the frame and also being for when the bolt control mechanism is arranged to act indirectly on the first member via the adaptor piece.