GB2233033A

GB2233033A - Deadlocking night latch

Info

Publication number: GB2233033A
Application number: GB9011587A
Authority: GB
Inventors: David Brian Legge
Original assignee: J Legge and Co Ltd
Current assignee: J Legge and Co Ltd
Priority date: 1989-05-23
Filing date: 1990-05-23
Publication date: 1991-01-02
Anticipated expiration: 2010-05-23
Also published as: GB8911834D0; GB2233033B; GB9011587D0

Abstract

A night latch comprising a latch bolt head 35 mounted for movement between an operative and an inoperative position and spring biased into the said operative position and drivable from said operative to said inoperative positions by either a first drive means 30 or a second drive means 32, 33, a deadlock member 48 operable to deadlock the latch bolt head in said operative position. and release means to release the deadlock member from said locking relationship on actuation of either of said drive means in the unlatching sense, said release means comprising a first member 18 drivable by either of said drive means to a first position in which the deadlock member is released from said locking relationship. without movement of the latch bolt head out of said operative position, and then to a second position during which further movement the latch bolt head is moved out of said operative position. The said first member is a plate 18 connected to the bolt but having lost motion therewith, thus permitting the two stage movement. Deadlocking lug engages shoulder 47 on the bolt in the deadlocking position. This is disengaged by camming of pin 65 of the deadlock plate 49 in notch 46 of the plate 18 when the latter is moved. <IMAGE>

Description

Title: "New and improved latch" Description of Invention This invention relates to a latch and particularly a night latch.

An object of the invention is to provide a new and improved latch and particularly a night latch.

According to one aspect of the invention we provide a night latch comprising a latch bolt head mounted relative to a housing for movement between an operative and an inoperative position and spring biased into an operative position and drivable from said operative position to an inoperative position by either a first drive means or a second drive means, a deadlock member operable to deadlock the latch bolt head in said operative position, and release means to release the deadlock member from said locking relationship on actuation of either of said drive means to drive the latch bolt head from said operative position to said inoperative position, said release means comprising a first member drivable by either of said drive means to a first position in which the deadlock member is released from said locking relationship, without movement of the latch bolt head out of said operative position, and then to a second position during which further movement the latch bolt head is moved out of said operative position.

The first member may comprise a latch lath connected to the latch bolt head for limited relative movement, the lath being drivable by either of said drive means and the lath being movable to the first position without movement of the bolt head by virtue of said permitted relative movement and movement of the lath from the first position to the second position being transmitted to the bolt head to move the bolt head out of said operative position.

The latch lath and bolt head may be inter-connected for limited rectilinear relative movement.

The lath may be spring biased towards the bolt head, the spring bias being of less magnitude than the spring bias applied to the bolt head to bias the bolt head into said operative position.

The deadlock member may comprise a pivoted locking plate having an abutment movable into locking engagement with an abutment provided on the bolt head and the deadlock member and the lath having inter-engageable cam means whereby movement of the lath to said first position causes movement of the deadlock member out of locking engagement with the bolt head.

The deadlock member may be normally spring biased into said locking engagement with the bolt head.

The deadlock member may be maintained out of said locking engagement with the bolt head when a sub-bolt is in an extended position, for example, when a wing provided with the night latch is in an opened position, the sub-bolt permitting the deadlock member to move into said locking engagement with the bolt head when the subbolt is displaced to a retracted position, for example, as a result of engagement of the sub-bolt with a striker plate, when the wing is closed.

The first drive means may comprise a handle or knob operated follower and the second drive means may comprise a cam or other drive part of a key operated cylinder lock.

According to a second aspect of the present invention we provide a cylinder lock comprising a barrel having a key releasable plug rotatable therein and the plug having a drive cam mounted thereon wherein the cam is drivingly connected to the plug in a plurality of angular positions.

The cam may have a boss part in which the plug is rotatively received, the boss part having a first abutment surface at a first angular position and a second abutment surface at a second different, angular position, the abutment surfaces being adapted to engage a drive transmitting element of the plug.

The first and second abutment surfaces may be at opposite ends of a part circumferentially extending slot formed in said boss part.

The drive transmitting element may comprise a radially extending part of the plug.

The radially extending part of the plug may be movably connected to the plug so as to be disposable in a desired angular relationship.

The radially extending part may comprise a screw threaded member received in a transversely extending bore of the plug.

Preferably the radially extending part of the plug comprises a pair of screw threaded members received in a diametrically extending threaded bore of the - plug, a desired one of the threaded members being disposed to project outwardly of the plug and the other of said members being disposed within the bore and in locking end-to-end relationship with the first mentioned member.

According to a third aspect of the present invention we provide a latch comprising a latch bolt mounted relative to a housing for movement between an operative and an inoperative position and provided with snib means to retain a latch bolt in an inoperative position the snib means comprising a snib member movable into retaining relationship with the latch bolt and a manually engageable member operatively connected to the snib member to move the snib member into said retaining relationship, the manually operable member comprising a rotatable member having a manually engageable peripheral surface portion which projects outwardly of the fore-end of a lock case in which the latch bolt is mounted, the peripheral surface portion being of curved configuration and having a radius of curvature at least generally equal to the distance between the surface and the axis of rotation of the member.

Preferably, the radius of curvature is generally equivalent to said distance.

The surface may be knurled or otherwise provided with means to provide a relatively high co-efficient of friction between the surface and an operator's finger.

The member may be a circular disc.

The member may have a pin and recess connection to the snib member to drive the snib member into said operative position.

The member have may a recess formed in the periphery thereof to receive a drive pin connected to the snib member. The member may drive the snib member rectilinearly in a direction generally parallel to the fore-end.

The snib member may have a detent means to retain the snib member in said operative or inoperative positions.

According to a fourth aspect of the present invention we provide a latch comprising a latch bolt mounted relative to a housing for movement between an operative and an inoperative position wherein the latch bolt comprises a latch bolt head releasably connectable to a latch body in either of two alternative positions wherein a curved surface of the latch bolt head faces in opposite directions and the connection being secured by a fastener means disposed so as to be accessible only when the latch bolt head is in a retracted position wherein the fastener means is presented for access through an opening in a side of the case or cap thereof.

The housing may comprise a case and a cap and the opening may be in a side of the case or the cap The fastener means may comprise two screw threaded fasteners and the opening may comprise two separate apertures, one for each fastener.

One of the latch bolt head or the latch bolt body may be provided with a projection which is receivable in a recess provided in the latch bolt body or the latch bolt head respectively.

The projection may be a tongue and the recess a groove.

One or more of the second to fourth aspects of the invention may be provided with each other or together with the first aspect of the invention.

An illustrative embodiment of the invention in the form of a mortice night latch for a door will now be more particularly described with reference to the accompanying drawings in which: FIGURE 1 is a front elevation of the latch; FIGURE 2 is a side elevation of the latch of Figure 1 with the cap removed; FIGURE 3 is a side elevation of the cap of the lock of Figures 1 and 2; FIGURE 4 is a longitudinal cross-sectional view through the cylinder lock of the latch of Figures 1 to 3, and FIGURE 5 is â section on the line 5-5 of Figure 4.

Referring to the Figures, the latch has a case 10 and an inner fore-end 11 whilst an outer fore-end 12 is fastened to the inner fore-end 11 by fasteners 13 in conventional manner. A cap 14 is secured to the case 10 by screw headed fasteners received in threaded apertures in pillar studs 15 - 17 in conventional manner. The ,case, fore-end and cap provide a housing.

A latch lath 18 is mounted for sliding movement within the case 10 by means of a latch guide stud 19 and a latch runner stud 20 fixed to the case 10 and received in slots 21, 22 respectively provided in the latch lath 18.

The lath 18 has an upstanding abutment flange 23 at its upper end and a similar abutment flange 24 at its lower end, the flanges 23, 24 being separated by a generally U-shaped slot 25 to accommodate a conventional spring biased follower 26.

The follower 26 has a projecting nose part 27 at each end, only one of which is shown in the Figures, which is received in a correspondingly dimensioned circular opening provided in the case 10 and cap 14 only one of which is shown at 28 in the Figures, whereby the follower 26 is journalled for pivotal movement. The follower has a square cross-section passage 29 therethrough which receives a correspondingly shaped shaft which carried a manually engageable novel handle at at least one end.

The follower 26 and arm 30 are adapted to engage the abutment flange 23 so that clockwise rotation of the follower 26 causes movement of the lath to the right in the Figure.

Mounted within the case 10 in conventional manner is a cylinder lock 31 having a drive cam 32 which is rotatable into driving engagement with the lower abutment flange 24 on clockwise rotation of the conventional plug 33 of the cylinder lock 31 to again drive the lath to the right in Figure 2.

Connected to the lath 18 is a latchbolt body 35.

This connection is afforded by a latch rod 36 threadedly engaged with the latch body 35 to project rearwardly ,thereof and to extend through apertures 37 formed in the flange 24 and a further flange 45 of the lath 18. The flange 45 of the lath 18 is formed with a downwardly extending part having a part-circular notch 46 therein.

The rod 36 has a washer 38 riveted thereto and a coil compression spring 39 is disposed to act between the washer 38 and the flange 24 so as normally to urge the body 35 to the right in Figure 2.

The latch body 35 has a bearing surface, not shown, which bears against the facing surface 40 of the lath 18.

The body 35 has an upstanding flange 41 against which a latch spring 42 abuts, the spring 42 having a part which encircles the pillar stud 15 and a tail part 43 which abuts a screw guide 44. The spring 42 serves normally to bias the body 35 to the left in Figure 2. The latch body 35 has a shoulder 47 engageable by a lug part 48 provided on a deadlock member 49 comprising a locking plate pivoted about a pivot stud 50 and normally biased to rotate in a clockwise direction by a coil spring 51 engaged between a pin 52 riveted to the plate 49 and a spring stud 53 riveted to the case 10.The locking plate 49 is normally pivoted in a clockwise direction by the spring 51 so as to engage the lug 48 with the shoulder 47 and thus to deadlock the latch body from movement inwardly to the right in Figure 2 when the latch body is in an operative position, i.e. extended from the housing fully to the left in Figure 2.

The latch body 35 carries a latch head 35a which can be secured to the latch body 35 with its conventional cam surface facing in either direction simply by reversing the latch head 35a (i.e. rotating it through 1800 about its direction of movement). This is to suit the direction in which a leaf, such as a door, to which the latch is attached, is closed into a frame provided with a keeper with which the cam surface co-operates to force the latch head 35a and hence the latch body 35 from said operative position towards said inoperative position against the bias of the spring 42. The latch head 35a is made as an extrusion and is provided with an integrally formed tongue 35d which is received in a groove 35e provided in the latch body 35. The latch head 35a is secured to the body 35 by head fixing screws 35b.Access can be gained to the head fixing screws 35b only when the head 35a is in its inoperative, i.e. a fully retracted, position when the screws 35b become aligned with openings 35c provided in the cap 14. If desired, other forms of projection and recess may be provided and the projection may be provided on the latch body and the recess in the latch head.

The latch head 35a is guided by an opening 3Sd formed in the inner and outer fore-ends in conventional manner.

Also projecting from the inner and outer fore-ends is a sub-bolt 60 having a runner stud 61 riveted thereto and received in a generally triangular slot 62 provided in the plate 49. The sub-bolt 60 has an end flange 60a which engages one end of a coil compression spring 63, the other end of which is carried by a spring support 64 so that the sub-bolt 60 is normally biased to the left in Figure 2.

The plate 49 has a stud 65 for engagement with the groove 46 of the flange 45 of the lath 18.

Also mounted within the case 10 is a snib bolt 70 mounted for rectilinear sliding movement in a direction parallel to the fore-ends 12, 13 by spring studs fixed in circular openings in the case 10 and received in ,elongate slots 72 of the snib bolt 70. Received within a cut-out 73 of the snib bolt 70 is a shaft 74 of a thumb wheel 75 which has a part circular recess 76 formed in its circumference which cut-out receives a drive peg 77 fixed to the snib bolt 70.

A snib spring 78 has a tail part 79 which engages an upstanding flange 80 of the case 10, a part 81 which partly encircles the pillar stud 16 and an arm 82 having a part circular end portion 83 to engage the peg 77 and act as a detent to retain the peg either in the position shown in Figure 2 in which the snib bolt is maintained in an inoperative position, or when the peg 77 engages the opposite side of the curved part 83 to retain the snib bolt 70 in an operative position. A nose part 84 of the snib bolt 70 is adapted to engage a shoulder 85 of the latch body 35. The thumb wheel 75 is in the form of a circular disc having the pivot pin 74 fixed thereto and the pivot pin 74 being journalled in apertures provided in the case and cap. The circumference of the thumb wheel 75 is knurled or otherwise adapted to improve the grip between the thumb wheel and the thumb of a user.

In use, with a door or other leaf, to which the night latch is attached, in a closed position, the subbolt 60 will be forced to the right in Figure 2 to a retracted position by engagement with a keeper provided on a frame with which the door is associated, whilst the latch head 35a will be in an extended operative position in door closing relationship with the keeper. The latch will be deadlocked by virtue of the coil compression spring 51 causing pivotal movement of the plate 49 in a clockwise direction to engage the lug 48 with the shoulder 47, sufficient pivotal movement of the plate 49 being permitted by virtue of the stud 61 being positioned in a greater width part of the slot 62.

When it is desired to open the door either of the two drive means may be actuated. That is to say, the follower 27 may be rotated by its associated handle, or lever, or the drive cam 32 may be rotated by means of a key engaged in the associated cylinder lock 31. Driving engagement between either the limb 30 and the flange 23 or the cam 32 and the flange 24 will initially cause movement of the lath 18 to the right in Figure 2 without movement being communicated to the latch head 35a or the latch body 35 by virtue of the limited relative movement permitted between the lath 18 and the body 35 by the presence of the coil compression spring 39.Since the spring 39 is weaker than the spring 42 the latch head 35a and latch body 35 will be maintained in their operative position by the spring 42 as well as the deadlocking provided by the lug 48 and abutment 47.

The initial movement of the lath 18 into a first position causes the groove 46 to move relative to the pin 65 and thus to cause the pin 65 to be cammed downwardly to cause anti-clockwise rotation of the plate 49 to move the lug 48 out of deadlocking relationship with the abutment 47. On completion of the permitted relative movement when the compression spring 39 becomes fully compressed, continued movement of the lath 18 from the first position towards a second position is communicated to the body 35 through the rod 36 and hence the latch head 35a will be moved from its operative position to a retracted inoperative position.

When the door is open the sub-bolt 60 is in an extended position in which the stud 61 is aligned with a smaller width part of the slot 62 and so the plate 49 is held in an in-operative position in which the lug 48 is maintained out of engagement with the lug 47, thereby permitting free movement of the latch head 35a so that the door can be closed.

With the door open the latch head 35a may be maintained in its inoperative retracted position by operation of the thumb wheel 75 to drive the snib bolt 70 into retaining relationship with the shoulder 85. When it is desired to release the latch head 35a the thumb wheel 75 can be rotated in the opposite direction. The reiatively large diameter of the thumb wheel 74 provides a convenient snib operation and minimises the risk of the user breaking a finger nail, which is a situation which frequently arises with snib levers previously provided.

The cylinder may be of the single type such that the latch can be further deadlocked by inserting and turning the key after closing the door.

However, the cam 32 must be correctly pcsitioned behind the abutment surface 24 of the lath latch when the key is at bottom dead centre, such that it will allow the key to be withdrawn. Accordingly, the cylinder lock requires to be handed according to the side of the lock on which it is required. In order to permit the cylinder lock to be provided on either side of the lock, the cam 32, as best shown in Figures 4 and 5, has a boss part 90 in which the plug 33 of the cylinder lock 31 is received.

The boss part 90 has a part circumferentially extending slot 91 formed therein, bounded by first and second abutment surfaces 92, 93. The plug 33 has a diametrically extending threaded bore 94 and two grub screws 95, 96 are threadedly received therein and are provided with driving sockets 97. According to the desired hand, the cam 32 is rotated to the desired position and the desired one of the grub screws 95, 96 is rotated so that an end part projects outwardly, as shown at 97 in the right-hand side of Figure 5. This outwardly projecting part abuts with one of the surfaces 92, 93 and limits movement of the cam. In Figure 5 the part of 97 engages the abutment surface 93 and thus limits movement of the cam in the full line position shown in Figure 5.

The other screw, shown at 96 in Figure 5, is engaged fully within the bore 94 and acts as a locking screw for the screw 95.

If it is desired to hand the lock oppositely, the position of the screws 95, 96 is reversed so as to limit movement of the cam to the dotted line position shown in Figure 5.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

1. A night latch comprising a latch bolt head mounted relative to a housing for movement between an operative and an inoperative position and spring biased into the said operative position and drivable from said operative position to an inoperative position by either a first drive means or a second drive means, a deadlock member operable to deadlock the latch bolt head in said operative position, and release means to release the deadlock member from said locking relationship on actuation of either of said drive means to drive the latch bolt head from said operative position to said inoperative position, said release means comprising a first member drivable by either of said drive means to a first position in which the deadlock member is released from said locking relationship, without movement of the latch bolt head out of said operative position, and then to a second position during which further movement the latch bolt head is moved out of said operative position.

2. A latch according to Claim 1 wherein the first member comprises a latch lath connected to the latch bolt head for limited relative movement, the lath being drivable by either of said drive means and the lath being movable to the first position without movement of the bolt head by virtue of said permitted relative movement and movement of the lath from the first position to the second position being transmitted to the bolt head to move the bolt head out of said operative position.

3. A latch according to Claim 2 wherein the latch lath and bolt head are inter-connected for limited rectilinear relative movement.

4. A latch according to Claim 2 or Claim 3 wherein the lath is spring biased towards the bolt head, the spring bias being of less magnitude than the spring bias applied to the bolt head to bias the bolt head into said operative position.

5. A latch according to any one of Claims 2 to 4 wherein the deadlock member comprises a pivoted locking plate having an abutment movable into locking engagement with an abutment provided on the bolt head and the deadlock member and the lath having inter-engageable cam means whereby movement of the lath to said first position causes movement of the deadlock member out of locking engagement with the bolt head.

6. A latch according to any one of the preceding claims wherein the deadlock member normally is spring biased into said locking engagement with the bolt head.

7. A latch according to any one of the preceding claims wherein the deadlock member is maintained out of said locking engagement with the bolt head when a subbolt is in an extended position.

8. A latch according to any one of the preceding claims wherein the first drive means comprises a handle or knob operated follower.

9. A latch according to any one of the preceding claims wherein the second drive means comprises a cam or other drive part of a key operated cylinder lock.

10. A latch according to any one of the preceding claims including a cylinder lock comprising a barrel ,having a key releasable plug rotatable therein and the plug having a drive cam mounted thereon wherein the cam is drivingly connected to the plug in a plurality of angular positions.

11. A cylinder lock comprising a barrel having a key releasable plug rotatable therein and the plug having a drive cam mounted thereon wherein the cam is drivingly connected to the plug in a plurality of angular positions.

12. A latch according to Claim 10 or Claim 11 wherein the cam has a boss part in which the plug is rotatively received, the boss part having a first abutment surface at a first angular position and a second abutment surface at a second, different, angular position, the abutment surfaces being adapted to engage a drive transmitting element of the plug.

13. A latch according to Claim 12 wherein the first and second abutment surfaces are at opposite ends of a part circumferentially extending slot formed in said boss part.

14. A latch according to Claim 12 or Claim 13 wherein the drive transmitting element comprises a radially extending part of the plug.

15. A latch according to Claim 14 wherein the radially extending part of the plug is movably connected to the plug so as to be disposable in a desired angular relationship.

16. A latch according to Claim 14 or Claim 15 wherein the radially extending part comprises a screw threaded member received in a transversely extending bore of the plug.

17. A latch according to any one of Claims 14 to 16 wherein the radially extending part of the plug comprises a pair of screw threaded members received in a diametrically extending threaded bore of the plug, a desired one of the threaded members being disposed to project outwardly of the plug and the other of said members being disposed within the bore and in locking end-to-end relationship with the first mentioned member.

18. A latch according to any one of the preceding claims including a snib means to retain the latch bolt in said inoperative position, the snib means comprising a snib member movable into retaining relationship with the latch bolt and a manually engageable member operatively connected to the snib member to move the snib member into said retaining relationship, the manually operable member comprising a rotatable member having a manually engageable peripheral surface portion which projects outwardly of the fore-end of a lock case in which the latch bolt is mounted, the peripheral surface portion being of curved configuration and having a radius of curvature at least generally equal to the distance between the surface and the axis of rotation of the member.

19. A latch comprising a latch bolt mounted relative to a housing for movement between an operative and an inoperative position and provided with snib means to retain the latch bolt in said inoperative position, the snib means comprising a snib member movable into retaining relationship with the latch bolt and a manually engageable member operatively connected to the snib member to move the snib member into said retaining relationship, the manually operable member comprising a rotatable member having a manually engageable peripheral surface portion which projects outwardly of the fore-end of a lock case in which the latch bolt is mounted, the peripheral surface portion being of curved configuration and having a radius of curvature at least generally equal to the distance between the surface and the axis of rotation of the member.

20. A latch according to Claim 18 or Claim 19 wherein the radius cf curvature is generally equivalent to said distance.

21. A latch according to any one of Claims 18 to 20 wherein the surface is knurled or otherwise provided with means to provide a relatively high co-efficient of friction between the surface and an operator's finger.

22. A latch according to any one of Claims 18 to 21 wherein the member is a circular disc.

23. A latch according to any one of Claims 18 to 22 wherein the member has a pin and recess connection to the snib member to drive the snib member into said operative position.

24. A latch according to any one of Claims 18 to 23 wherein the member has a recess formed in the periphery thereof to receive a drive pin connected to the snib member.

25. A latch according to any one of Claims 18 to 24 wherein the member drives the snib member rectilinearly in a direction generally parallel to the fore-end.

26. A latch according to any one of Claims 18 to 25 wherein the snib member has a detent means to retain the snib member in said operative or inoperative positions.

27. A latch according to any one of the preceding claims including a latch bolt which comprises a latch bolt head releasably connectable to a latch body in either of two alternative positions wherein a cam surface of the latch bolt head faces in opposite operative directions and the connection being secured by a fastener means disposed so as to be accessible from the exterior of the housing only when the latch bolt head is in a said inoperative position wherein the fastener means IS presented for access through an opening in the housing.

28. A latch comprising a latch bolt mounted relative to a housing for movement between an operative and an inoperative position wherein the latch bolt comprises a latch bolt head releasably connectable to a latch body in either of two alternative positions wherein a cam surface of the latch bolt head faces in opposite operative directions and the connection being secured by a fastener means disposed so as to be accessible from the exterior of the housing only when the latch bolt head is in a said inoperative position wherein the fastener means is presented for access through an opening in the housing.

29. A latch according to Claim 27 or Claim 28 wherein the housing comprises a case and a cap and the opening is in a side of the case or the cap thereof.

30. A latch according to any one of claims 27 to 29 wherein the fastener means comprises two screw threaded fasteners and the opening comprises two separate apertures, one for each fastener.

31. A latch according to any one of Claims 27 to 30 wherein one of the latch bolt head and the latch bolt body is provided with a projection which is receivable in a recess provided in the latch bolt body, or the latch bolt head respectively.

31. The projection may be a tongue and the recess a groove.

32. A latch substantially as hereinbefore described with reference to the accompanying drawings.

33. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.