US3909052A

US3909052A - Door latches

Info

Publication number: US3909052A
Application number: US379434A
Authority: US
Inventors: Michael Joseph James
Original assignee: Micro and Precision Mouldings Cheltenham Ltd
Current assignee: Micro and Precision Mouldings Cheltenham Ltd
Priority date: 1972-07-19
Filing date: 1973-07-16
Publication date: 1975-09-30
Anticipated expiration: 1992-09-30
Also published as: GB1421905A

Abstract

A tubular mortice latch has a slam bolt slidable within a tubular body under the action of a rotary actuator. The rotary actuator, bolt and a spring acting on the bolt are formed as a sub-assembly insertable as a unit into the body thereby simplifying manufacture of the latch. The spring may be doubleacting in that it acts on the one hand to urge the bolt towards its latching position and acts on the other hand on the actuator to urge it towards its normal resting position.

Description

United States Patent 1191 James 1 DOOR LATCHES [75] Inventor: Michael Joseph James, Cheltenham,

England Micro & Precision Mouldings (Cheltenham Limited), Cheltenham, England [22] Filed: July 16, 1973 [21] Appl. No.: 379,434

[73] Assignee:

[30] Foreign Application Priority Data July 19.1972 United Kingdom 33701/72 [52] US. Cl 292/169; 292/l69.l6 [51] Int. Cl. EOSC 1/12 [58] Field of Search 292/D1G. 38, 169.

[56] References Cited UNITED STATES PATENTS 9/1912 Anderson ..292/169.l6

[451 Sept. 30, 1975 1.559.037 10/1925 Floyd 292/169.16 1.871.633 8/1932 Ter Meer 292/169 X 3.459.448 8/1969 Russell et a1. 292/169 X 3,544,147 12/1970 James 292/169 3,580,622 5/1971 Morgan 292/169 3,655.230 4/1972 Armstrong 292/169 Primary Examiner-Roy D. Frazier Assistant Etaminer-Peter A. Aschenbrenner Attorney, Agent, or Firm-Young & Thompson 57 1 ABSTRACT 9 Claims, 9 Drawing Figures DOOR LATCHES FIELD OF THE INVENTION This invention relates to door latches of the tubular mortice type. Such a latch has a tubular body for fitting into the door, a slam bolt slidable in the body and spring loaded to a projecting latching position, and a rotary actuator mounted within the body for rotary connection to a door handle. Turning of the actuator by the handle, about an axis at right angles to the bolt axis, in use acts to draw the bolt into the body to a release position.

SUMMARY OF THE INVENTION A mortice latch assembly comprises a tubular body and a sub-assembly, including a bolt, bolt-spring and rotary actuator, fitted as such through one end of the body, the parts of the sub-assembly being held together by engagement of an operating projection of the actuator with the bolt.

Preferably the sub-assembly includes all the parts of the latch other than the body, and all parts other than the spring are conveniently plastics mouldings. The body may be a one-piece moulding closed at the inner end, the sub-assembly being fitted into the body through the outer end aperture from which the bolt projects for latching purposes. The actuator may have snap-in engagement with'the body to retain the subassembly, and this engagement may be between side bearing bosses on the actuator and bearing apertures or surfaces in the body moulding.

The invention also provides a mortice latch assembly comprising a tubular body, a slam bolt slidable in the body between a projecting latching position and a drawn back release position, a rotary actuator mounted in the body and which engages the bolt to move the latter to the release position, and a bolt spring which on the one hand acts on the bolt to urge the latter towards the latching position and on the other hand acts on the actuator to urge the latter towards a normal resting position or to retain it in that position.

The latch assembly preferably includes a follower which provides a spring abutment and engages the actuator to transmit the spring force thereto, and this follower may slidably engage the body. The rotary actuator is preferably double acting, i.e. turnable in either direction to release the latch, with a central resting position and it may have a projecting limb which has snap-in engagement with the bolt for operative connection thereto.

The bolt and the follower are preferably formed with profiled surfaces, that on the bolt being engaged by the actuator limb with a camrning action for bolt withdrawal and that on the follower engaging the actuator limb to urge the latter to said resting position. Engagement of the actuator limb with the bolt may employ the resilience of the bolt material to provide said snap-in engagement, and it may serve to hold the bolt, spring, follower and actuator together as a unitary subassembly which can be fitted as such into the body.

Use of the bolt spring to provide a return force urging the actuator to its resting position provides a very simple and compact arrangement suitable for use with socalled continental door furniture with'handle sets which do not include handle return springs, and in this case the spring return of the actuator also provides the handle return force. The fitting of the movable parts of the latch as a sub-assembly, retained as such by mere inter-engagement of the actuator and the bolts, provides very rapid and easy assembly which is reflected in low overall manufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an outer end view of the assembly,

FIG. 2 is a sectional view on the line II II in FIG.

FIG. 3 is a sectional view on the line III III in FIG.

1, FIG. 4 is a sectional view on the line IV IV in FIG.

FIG. 5 is a detail view of a body of the assembly,

FIG. 6 is a detail sectional view on the line VI VI in FIG. 2, of a bolt of the assembly, I

FIG. 7 is a detail sectional view on the line VII VII in FIG. 6, and

FIG. 8 is a detail sectional view on the line VIII VIII in FIG. 6, and

FIG. 9 is a detail view of a follower of the assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT A one-piece tubular moulded body 1 has a rectangular outer end fixing flange land is closed at the inner end. Considering the flange 2 mounted in the normal manner (as shown in the drawings) with its major axis vertical, the body 1 has flat parallel side walls 3 joined by concentric arcuate top and bottom walls 4, these being continuous from side bearing apertures 5 in the body through to the outer end aperture 6 from which a slam bolt 7 projects for latching purposes.

The slam bolt 7 has a normal nose profile for engagement with a complementary keeper (not shown) and from the nose portion 8, which is hollow, has parallel spaced side limbs 9 which extend into the body 1 and slidably engage the side walls 3 thereof. A rotary actuator 10 has opposed bearing bosses l2, and the bearing apertures 5 in the body 1, see particularly FIG. 5, are elongated axially of the body 1 with curved ends providing effective inner and outer arcuate bearing

surfaces

5a and 5b which are laterally offset and engaged by the bearing bosses 12.

The actuator 10 has an outwardly projecting limb 13 which tapers towards the free end at which it has opposed side projections 14, in the form of circular stubs which respectively engage generally V-shaped ca'mming surfaces 15 formed internally on the bolt limbs 9 adjacent to the inner free ends thereof. A follower moulding 16 has a central portion 17 extending vertically within the housing and which has a sliding fit between the bolt limbs 9 which, as shown more particularly inFIG. 8, are of channel section. At each end this portion has inwardly and outwardly projecting limbs 18 which slidably engage the upper and lower walls 4 of the body 1, and it also has a central outward projection 19 which fits into and locates the inner end of a spring 20 the outer end of which locates within the hollow bolt nose 8.

The follower 16 also has two side projections 22 which provide snap-in initial fitting between the bolt limbs 9 before the bolt 7 is fitted to the actuator 10, the follower 16 acting as a spring abutment and transmitting the spring force to the actuator 10 during latch operation. On assembly, the projections 22 snap into position past inner end walls 21 on the bolt limbs 9 and on which the profiles 15 are formed. On its inner side the main portion 17 of the follower (see FIG. 3) has a V- shaped camming profile 23, opposite but generally similar to that of the bolt limbs 9, and this engages a radiused end of the actuator limb 13.

The assembly of the described latch is particularly rapid and simple. The spring 20 is placed between the bolt limbs 9 and is located on and compressed by the follower 16 as the latter is snapped into position between the limbs 9. The actuator 10 is now fitted, its projecting limb 13 being inserted between the bolt limbs 9 and snapped into position past the end walls 21 in operative engagement with the bolt camming surfaces 15 while at the same time engaged by the follower camming surface 23. This completes a sub-assembly of all the movable parts of the latch, this sub-assembly -then being inserted into the outer end of the housing 1 and pushed home until projections 24 on the bearing bosses 12 snap into engagement with said outer bearing surfaces b, thereby retaining the sub-assembly within the body 1.

The actuator has a throughbore 25 of square section to accept the usual square-section shaft (not shown) interconnecting inner and outer door handles (also not shown). Turning of the actuator by the shaft causes the actuator stubs 14 to move along the cam surfaces on the bolt 7, the camming action withdrawing the bolt 7 into the body 1 against the spring'force. Angular movement of the actuator 10 is limited by engagement of side faces 26 of a projecting tail portion 27 of the actuator with the top and bottom walls 4 of the body 1 inwardly of the bearing apertures 5.

As the actuator stubs 14 move along the camming surfaces 15 of the bolt 7 they similarly move along the camming surface 23 on the follower 16, which thus tranmits the spring force to the double-acting actuator 10 with a centring action. This acts to return the actuator to the resting position illustrated, and can also provide the return force for unspring handle sets; as will be appreciated this centring action is present in all bolt positions. At the limit of angular movement, the actuator limb 13 reaches the corresponding ends of each

camming surface

15 and 23, thereby assisting in limiting the angular movement by engagement of the actuator limb 13 with the corresponding limb 18 of the follower 16. Thus the angular movement is limited in a solid manner by reaction with the body I on both sides of the shaft, providing a very strong construction.

What is claimed is:

l. A mortice latch assembly comprising a tubular body and a subassembly insertable as a unit through one end of said tubular body, said subassembly com prising a slam bolt and a bolt spring and a follower and a rotary actuator, the bolt being slidable in the body between a forward projecting latching position and a rear retracted release position, the actuator seating on the body for angular movement transverse to the direction of bolt sliding movement, the bolt having side limbs that extend rearwardly from a front nose portion of the bolt, the follower being slidable in the body between the bolt limbs, the spring being disposed between the bolt limbs and acting in compression between the rear of the bolt nose and the front of the follower, the actuator, having an operating projection between the bolt limbs that engages with the bolt limbs to hold the subassembly together for fitting into the body, the bolt limbs having cam surfaces thereon that contact the actuator projection and that are inclined to the direction of bolt sliding movement so that rotation of the actuator in one direction from a rest position moves the bolt rearwardly, the follower having a cam surface thereon that contacts the actuator projection and that is inclined to the direction of bolt sliding movement and oppositely inclined to the cam surfaces of the bolt limbs so that rotation of the actuator in said one direction from said rest position moves the follower forwardly.

2. A latch assembly as claimed in claim 1, wherein the actuator has a snap-in engagement with the body to retain the said assembly within the body.

3. A latch assembly as claimed in claim 2, wherein said snap-in engagement is between side bearing bosses on the actuator and bearing surfaces on the body.

4. A latch assembly as claimed in claim 20, in which the follower has an initial snap-in engagement with the bolt limbs to facilitate assembly of the subassembly.

5. A latch assembly as claimed in claim 1, in which the actuator is double acting and said rest position is a centered position of the actuator projection in the body.

6. A latch assembly as claimed in claim 1, in which the actuator projection has snap-in engagement with the bolt for operative connection thereto.

7. A latch assembly as claimed in claim 1, in which the actuator projection has oppositely projecting stubs which engage the inclined cam surfaces of the bolt limbs and of the follower.

8. A latch assembly as claimed in claim 1, in which the cam surfaces on the bolt limbs are forwardly concave and the cam surface on the follower is rearwardly concave.

9. A latch assembly as claimed in claim 8, in which the cam surfaces are substantially V-shaped.

Claims

1. A mortice latch assembly comprising a tubular body and a subassembly insertable as a unit through one end of said tubular body, said subassembly comprising a slam bolt and a bolt spring and a follower and a rotary actuator, the bolt being slidable in the body between a forward projecting latching position and a rear retracted release position, the actuator seating on the body for angular movement transverse to the direction of bolt sliding movement, the bolt having side limbs that extend rearwardly from a front nose portion of the bolt, the follower being slidable in the body between the bolt limbs, the spring being disposed between the bolt limbs and acting in compression between the rear of the bolt nose and the front of the follower, the actuator, having an operating projection between the bolt limbs that engages with the bolt limbs to hold the subassembly together for fitting into the body, the bolt limbs having cam surfaces thereon that contact the actuator projection and that are inclined to the direction of bolt sliding movement so that rotation of the actuator in one direction from a rest position moves the bolt rearwardly, the follower having a cam surface thereon that contacts the actuator projection and that is inclined to the direction of bolt sliding movement and oppositely inclined to the cam surfaces of the bolt limbs so that rotation of the actuator in said one direction from said rest position moves the follower forwardly.