GB2123070A - Lockable door latch - Google Patents

Abstract

The door latch assembly comprises a handle 3 rotatably mounted in a handleplate 1 and a locking member 4 in the form of a rocker 4. The rocker 4 is mounted in an aperture 5 in the handleplate 1 so as to be externally accessible for pivotal movement between an operative locking position, in which it engages in a peripheral recess 21 in a handle-mounting flange 7, and an inoperative position in which it is clear of the flange 7. When in the locking position the rocker 4 engages an undercut end face 22, Fig. 10, in the recess 21 to block movement of the handle 3 in the latch-release direction. At the other end the recess 21 has a cam face 24 which, when the handle 3 is turned in the opposite direction with the rocker 4 in the locked position, engages the rocker 4 and displaces it to the inoperative position. <IMAGE>

Description

SPECIFICATION Door furniture This invention relates to door furniture, and in particular to lockable door handle assemblies.

It is often desired that the door of a room should be lockable on one side, usually on the inner side to ensure privacy for the occupant.

Examples are the doors of toilets and bathrooms, which conventionally have been fitted with separate locking bolt assemblies. This has the disadvantage that if a disabled or elderly occupant is in difficulties or taken ill, for example, entry to render assistance requires that the door be forced open with considerable force which causes damage and may injure the occupant as the door bursts open. As an alternative, matched handle sets are available including one handle assembly which incorporates a locking device which, in an emergency, can be released from the opposite side of the door.

However, such handle sets have two major disadvantages. The first is the increased complexity and cost, as the release means have to operate through the latch-operating spindle which interconnects the handles, so that a special hollow spindle is required. The second is that a suitable tool, commonly a long thin screwdriver, is required to effect release and such a tool may not be to hand when the need arises. A further disadvantage, when lever handles are used as is commonly the case, is that the handle sets are "handled" as the inner and outer assemblies are not interchangeable.

The principle object of the invention is to provide a locking handle assembly which can be released from the opposite side of the door without the use of tools. A further object is to provide such an assembly which, when it incorporates a lever handle, can be supplied as part of a non-handled handle set which is thus usable with any door.

According to the invention a door handle assembly comprises a handleplate for mounting on a door, a handle rotatably mounted in the handleplate for coupling through a latchoperating spindle with an associated handle on the opposite side of the door, a locking member mounted on the handleplate for movement between an operative locking position and an inoperative position, and locking and release formations rotatable with the handle and so arranged that when the locking member is in the operative position it is engaged by the locking formation to block rotation of the handle in the latch-release direction whereas handle rotation in the opposite direction causes the release formation to engage the locking member and displace it to the inoperative position.

Thus when the door is locked on the inside, it being assumed in the following description that the locking handle is fitted on the inner side of the door as is usual, the coupling of the handles through the normal latch-operating spindle blocks turning of the outer handle in the latch-release direction which indicates that the room is occupied and that the occupant desires privacy. However, should the need arise the locking action can be overridden merely by turning the outer door handle in the opposite direction.

Preferably both said formations are formed on a flange mounted on, or formed integral with, the shank of the handle within the handleplate. Such a flange may have a peripheral notch or recess, one side of which has a stop face providing the locking formation and the other side of which has an inclined face which engages the locking member with a camming action. This flange may be circular to provide a bearing for the handle in the handleplate, and it may co-operate with a double-acting return spring which acts to centre the handle in the normal resting position.

The locking member may be a rocker which projects from the outer face of the handleplate for manual operation and, at least in the locking position, projects on the inner side of the handleplate for engagement by said locking and release formations. It may be mounted on a pivot provided with a detent projection which engages the rocker to provide a snap-over action thereof between said operative and inoperative positions, and also to retain it in either of those positions.

Preferably the rocker has a forked pivot formation which enables it to be a removable snap-on fitting on the pivot which for this purpose may extend across said aperture in the handleplate. This enable a handle set to be supplied which is not handed---one handle assembly being supplied with the rocker fitted and the other handle assembly being identical (other than handing of the handles) except that the handleplate is fitted with a blanking plate replacing the rocker and blanking off the aperture in that handleplate. Thus, the rocker and the blanking plate can be interchanged, should this be necessary to suit the door, before the handle set is fitted.

The invention will now be further described with reference to the accompanying drawings which illustrate, by way of example, an illustrative embodiment of the invention in the form of a lever handle assembly. In the drawings: Figure 1 is an outer side face view of the handle assembly; Figure 2 is an inner side view thereof; Figure 3 is a cross-sectional view taken on the line 111-111 in Fig. 1; Figure 4 is an inner side view of a handleplate component of the assembly; Figure 5 is a detail of Fig. 3, to an enlarged scale; Figure 6 is a side view of a locking member of the assembly; Figure 7 is a cross-sectional view taken on the line VII-VII in Fig. 6; Figure 8 is a detail view of a handle component of the assembly; Figure 9 is a cross-sectional view taken on the line IX-IX in Fig. 8; and Figure 10 is a fragmentary detail view of the handle component as seen from above in Fig. 8.

The door handle assembly illustrated comprises three main components, each a plastics injection moulding, namely a rectangular handleplate 1 with corner screw-fixing holes 2, a lever handle 3 and a locking member in the form of rocker 4. The rocker 4 is located in a rectangular aperture 5 disposed centrally in the handleplate 1 above the handle 3, and it projects at the outer face of the handleplate 1 so as to be accessible for manual operation.

It can rock between an operative locking position, in which the handle 3 is locked against movement in the downward latch-release direction, and an inoperative position in which the handle 3 is free to turn.

Integral with a shank portion 6 of the handle moulding 3 is an inner circular flange 7 which is housed within the hollow handleplate 1 and turns with the handle. The flange 7 takes a bearing within an internal circular wall 8 of the handleplate 1, and the handle 3 is located against outward axial movement by engagement of the flange 7 with the edge of an inner circular wall 9 within the handleplate 1. It is located in the opposite direction by an annular lip 10 through which the shank 6 projects and which engages behind a rectangular step 11 on the shank 6.

The handle 3 is shown in a central resting position, and it can be turned in either direction through a range of movement determined by an arcuate stop 1 2 moulded in the handleplate 1 on the wall 8. The flange 7 has an arcuate recess 1 3 which provides clearance for the stop 12, and the radial ends 14 and 1 5 of this recess respectively engage the stop 1 2 to limit handle movement in the opposite latch-release and locking-release directions.

The flange 7 co-operates with a double-acting helical return spring 1 6 housed in a recess defined between an annular groove 1 7 in the shank 6 and the wall 9. The ends of the spring 1 6 engage a rectangular projection 1 8 on the wall 9 and a projection 1 9 of the same thickness extending across the groove 1 7.

Thus the spring 1 6 provides a return force which is operative for either direction of handle movement, and it tends to retain the handle 3 in the resting position in which the projections 1 8 and 1 9 are radially aligned.

The flange 7 has an angled aperture 20 of elliptical profile though which the spring 1 6 is, on assembly, threaded into its fitted position after fitting of the handle 3.

The flange 7 has a peripheral recess 21 which, in the handle resting position, registers with the rocker 4. At one end this recess has an undercut face 22 providing a locking formation, and at the other end it has a helicallygenerated cam face 24 providing a release formation. The rocker 4 is mounted on a pivot 23 which extends centrally across the aperture 5, this pivot being integral with the handleplate moulding 1. In the inoperative position illustrated in Fig. 3 the rocker 4 is clear of the flange 7, and the handle 3 is free to turn in either direction and specifically in the latch-release direction. The shank 6 has a square-profile axial bore 6a to receive the usual latch-release spindle which passes through the door and couples the handle 3 to the handle on the opposite side of the door.

On movement of the rocker 4 to the operative locking position, ie. anti-clockwise as viewed in Fig. 3, the lower end portion 25 of the rocker engages in the notch 21 in the flange 7. Thus the handle 3 is blocked against movement in the latch-release direction, with such movement being prevented by the interengagement of the end face 22 and the rocker 4.

If it becomes necessary to open the door from the opposite side when the rocker 4 is in the locking position, the opposite door handle is initially turned in the locking-release direction. This direction of movement is allowed by the formation of the helical face 24 which engages the rocker 4 with a camming action and, as the flange 7 turns, displaces the rocker 4 and moves it back to the inoperative position. The door is now unlocked.

The rocker 4, shown more particularly in Figs. 6 and 7, is a symmetrical moulding with said end portion 25 identical to the opposite end portion 26. Thus the rocker is reversible on the pivot 23, and it has snap-on engagement therewith by means of a bifurcated bearing portion 27 the opposed limbs 27a and 27b of which embrace the pivot 23. The rocker is moulded from plastics material of adequate resilience and flexibility to allow the snap-on fitting to the pivot 23, for example from an acetyl resin. The inner bearing surface 28 of the rocker 4 has a central axial rib 29 of convex semi-circular profile which engages a similar-section detent projection 30 on the pivot 23 to provide a snap-over rocker action. The specific shape of the pivot 23 is shown clearly to an enlarged scale in Fig. 5, and it has upper and lower part-cylindrical bearing surface 31 and 32 engaged by the rocker bearing surface 28. At the outer side it has a flattened portion from which said detent projection 30 projects.

Although the pivot 23 has a symmetrical cross section the axis of symmetry, on which the projection 30 is centred, is not disposed normal to the general plane of the handleplate 1 but is inclined upwardly and outwardly thereof at an angle of 2+ . This is selected so that the rocker 4 is firmly retained in both the operative position and in the the inoperative position, in which the projection 29 engages above the projection 30 with the upper end portion 26 engaging the door surface and the lower end portion 25 clear of the flange 7.

The lower end of the rocker 4 then projects, as shown in Fig. 3, so as to be readily accessible for finger operation. When the lower end of the rocker 4 is depressed the projection 29 snaps over the projection 30, and engages below the latter to hold the rocker 4 in the operative locking position in which the lower end portion 25 is firmly held against the side of the recess 21.

Referring particularly to Figs. 7 and 10, the locking face 22 of the flange 7 has as previously mentioned an undercut formation, the angle of undercut being 10 . The side faces of the rocker end portions 25 and 26 have complementary undercut blocking faces 34 and 35. Thus-the locking 22 and blocking 34, 35 faces interengage in an interlocking manner to effect !ocking of the handle 3, and any flexing of the parts on an attempt to turn the outer door handle in the latch-release direction is not sufficient to disengage these faces.

When correctly engaged with the pivot 23 the rocker 4 is retained captive in the handleplate 1 by upper and lower part-cylindrical bearing surfaces 36 and 37 which, for this purpose, respectively engage complementary surfaces 38 and 39 on the upper and lower ends of the rocker 4. However, the rocker 4 can easily be removed for fitting in the oppositely handed handle assembly of a matched handle set. This is achieved by turning it so that it projects more or less normally to the handleplate 1, when it can be snapped off the pivot 23, in the upward direction, and then withdrawn from the aperture 5. Resitting of the rocker 4, in the handleplate of the other handle assembly, employs the reverse procedure. When the assembly is fitted to a door the latter determines the movement of the rocker 4 to the inoperative position thereof.

Thus the surfaces 36, 38 and 37, 39 remain in engagement and the rocker 4 cannot accidentally become detached.

Claims (11)

1. A door handle assembly comprising a handleplate for mounting on a door, a handle rotatably mounted in the handleplate for coupling through a latch-operating spindle with an associated handle on the opposite side of the door, a locking member mounted on the handleplate for movement between an operative locking position and an inoperative position, and locking and release formations rotatable with the handle an so arranged that when the locking member is in the operative position it is engaged by the locking formation to block rotation of the handle in the latchrelease direction whereas handle rotation in the opposite direction causes the release formation to engage the locking member and displace it to the inoperative position.

2. A door handle assembly according to claim 1, wherein both said formations are formed on a flange mounted on, or formed integral with, a shank of the handle within the handleplate.

3. A door handle assembly according to claim 2, wherein said flange has a peripheral notch or recess, one side of which has a stop face providing the locking formation and the other side of which has an inclined face which engages the locking member with a camming action.

4. A door handle assembly according to claim 2 or claim 3, wherein said flange is circular to provide a bearing for the handle in the handleplate.

5. A door handle assembly according to any one of claims 2 to 4, wherein said flange co-operates with a double-acting return spring which acts to centre the handle in the normal resting position.

6. A door handle assembly according to claim 4 or claim 5, wherein said flange has an arcuate recess the radial ends of which respectively engage an arcuate stop in the handleplate to limit the range of handle movement.

7. A door handle assembly according to any one of the preceding claims, wherein said locking member is a rocker which projects from the outer face of the handleplate for manual operation and, at least in the locking position, projects on the inner side of the handleplate for engagement by said locking and release formations.

8. A door handle assembly according to claim 7, wherein said rocker is mounted on a pivot provided with a detent projection which engages the rocker to provide a snap-over action thereof between said operative and inoperative positions, and also to retain it in either of such positions.

9. A door handle assembly according to claim 7 or claim 8, wherein said rocker has a forked pivot formation which enables it to be a removable snap-on fitting on the pivot which for this purpose may extend across said aperture in the handleplate.

10. A handle set which is not handed and comprises one handle assembly in accordance with claim 9 and another handle assembly which is identical (other than handing of the handles) with the first except that the handleplate thereof is fitted with a blanking plate replacing the rocker and blanking off the aperture in that handleplate, the rocker and the blanking plate being interchangeable.

11. A door handle assembly according to any one of claims 1 to 9, wherein the handleplate, the handle and the locking mem ber are all plastics mouldings.

1 2. A door handle assembly constructed and arranged substantially as herein particularly described with reference to the accompanying drawings.