GB2276657A

GB2276657A - Mounting a spindle on a follower

Info

Publication number: GB2276657A
Application number: GB9306566A
Authority: GB
Inventors: Peter James Thorley
Original assignee: ELEMENTER IND DESIGN Ltd
Current assignee: ELEMENTER IND DESIGN Ltd
Priority date: 1993-03-30
Filing date: 1993-03-30
Publication date: 1994-10-05
Anticipated expiration: 2013-03-30
Also published as: GB9306566D0; GB2276657B

Abstract

A door lock mechanism comprises a latch bolt 12 and a rotatable follower 14 in operative association with the latch bolt 12, the follower 14 having a square aperture 16 to receive, in use, the spindle 18 of an operating handle. A spring-loaded ball bearing 22 is associated with one face 20 of the square aperture 16 to reduce any play between the spindle 18 and the side faces of the aperture 16. The follower 14 includes a radial bore 24 extending from a face 20 of the aperture 16 in a radially outwards direction, the spring-loaded ball bearing 22 being mounted in the radial bore 24. <IMAGE>

Description

DOOR LOCK MECHANISM This invention relates to a door lock mechanism.

Door lock mechanism are known comprising a latch bolt and a rotatable follower in operative association with the latch bolt. Rotation of the follower causes longitudinal movement of the latch bolt between an open lock position and a closed lock position. The follower has a square aperture and the operating handle includes a square cross-section spindle which is marginally smaller than the aperture to allow ease of assembly of the spindle in the follower aperture. It is also known to provide a leaf spring in one face of the square aperture to reduce any play between the spindle and the sides of the aperture.

Such a door mechanism suffers from the disadvantage that it is not always easy to insert the spindle in the follower aperture and that such an arrangement does nct necessarily take up any wear that may occur in the spindle or the side faces of the aperture.

We have now discovered that these disadvantages can be at least partly overcome by the use of a ball bearing assembly to reduce the play between the spindle and the the sides of the follower aperture.

Thus, according to a first aspect of the present irvention there is provided a door lock mechanism comprising: (i) a latch bolt; (ii) a rotatable follower in operative association with the latch bolt, the follower having a polygonal aperture to receive, in use, the spindle of an operating handle; and (iii) spring-loaded play-reducing means associated with at least one face of the polygonal aperture to reduce any play between the spindle and the sides of the aperture, characterised in that the play-reducing means comprises a spring-loaded ball bearing.

In the door lock mechanism according to the invention, the follower preferably includes a radial bore extending from a face of the aperture in a radially outwards direction, the spring-loaded ball bearing being mounted in the radial bore.

The ball bearing may comprise a helical spring positioned in the radial bore, a ball support cup urged by the helical spring in a radially inwards direction and supporting a bearing ball which partly protrudes from the bore into the aperture.

Ideally, the radial bore is a through bore, the radially outer end of which is closed by a removeable plug such as in the form of a screw.

In the door lock mechanism according to the invention the aperture usually has the shape of a regular polygon, usually has an even number of sides and in the majority of embodiments is square, although other shapes such as a hexagon may also be used.

Usually, it is only necessary that a ball bearing is provided in one face of the aperture, although it is possible to additionally provide ball bearings on other faces of the aperture, especially if play in other directions is to be reduced. It is however preferred not to provide ball bearings in opposite faces of the aperture.

According to a second aspect of the invention there is provided a door lock mechanism and associated operating handle comprising: (i) a latch bolt; (ii) a rotatable follower in operative association with the latch bolt, the follower having a polygonal aperture; (iii) an operating handle including a polygonal cross-section spindle having the same general shape as that of the follower aperture but being dimensionally smaller to allow assembly of the spindle in the follower aperture; and (iv) spring-loaded play-reducing means associated with at least one face of the polygonal aperture to reduce any play between the spindle and the sides of the aperture, characterised in that the play-reducing means comprises a spring-loaded ball bearing.

We prefer that the linear dimensions of the spindle cross-section are at least 98%, such as between 98.5% and 99.5k of the corresponding dimensions of the follower aperture.

The invention will now be described in further detail with reference to the accompanying drawings in which: Figure 1 is a front view of a door lock mechanism according to the invention; and Figure 2 shows, in enlarged scale, a cross-sectional view of part of the lock mechanism shown in Figure 1, together with the spindle of an associated operating handle.

In the drawings, there is shown a door lock mechanism 10 comprising a facing plate 11 to which is secured a support plate 13. It should be recognised that only those features of the lock mechanism pertinent to the present invention have been included in the Figures, for the sake of clarity.

Mounted on the support plate 13 for longitudinal movement is a latch bolt arm 15. This arm extends through the facing plate 11 and carries a latch bolt 12 at its extreme end.

The arm 15 is urged to the right hand side as viewed in Figure 1 by action of a coil spring 19 which abuts a latch-bolt moving plate 17 carried on the arm 13.

Also mounted on the support plate 13, for rotation movement, is a follower 14. The follower 14 has a radially extending finger 21 which is in contact with the latch-bolt moving plate, the arrangement being such that rotation of the follower in a clock-wise direction as viewed in the drawings causes longitudinal movement of the arm 15 in the right hand direction, causing retraction of the latch-bolt 12.

The follower 14 is provided with a square-shaped through aperture 16, into which the spindle 18 of an operating handle (not shown) is inserted. This spindle carries at each end a hand grip in a manner well known in the art, at least one of the hand grips being removeable for ease of assembly.

The aperture 16 is slightly inclined to the horizontal, such as by from 1 to 20.

As shown in Figure ì, the follower 14 carries a side arm 23 which is acted upon by a coil spring 25.

As particularly shown in Figure 2, the follower 14 is provided with a single radial through bore 24, which has a relatively narrow diameter internally threaded portion 29 and an inner relatively wider diameter portion 27. Mounted within the radial bore is a ball bearing assembly generally designated by the reference 22. The ball bearing assembly 22 comprises a helical spring 26 which is positioned in a tensioned state between a grub screw 32 threaded into the narrow diameter portion 29 of the bore 24 and a ball support cup 28 mounted for sliding movement in the wider diameter portion 27 of the bore 22. A bearing ball 30 is supported in the ball support cup 28 and protrudes partly into the aperture 16 from the side face 20 thereof. The protruding bearing ball 30 presses, by virtue of the force provided by the helical spring 26, against one face of the spindle 18.

The spindle is thereby pushed towards the right, until is abuts against the opposite face 33 of the aperture 16.

The dimensions of some parts have been exaggerated in the drawings, for the sake of clarity. In a typical example, the aperture 16 has a side dimension of 8.00 mm and the spindle has a side dimension of 7.95 mm. The bearing ball 30 has a diameter of 3.00 mm and protrudes into the aperture 16 by up te 1.00 mm, thereby to allow for wear.

Claims

1. A door lock mechanism comprising: (i) a latch bolt (12); (ii) a rotatable follower (14) in operative association with the latch bolt (12), the follower (14) having a polygonal aperture (16) to receive, in use, the spindle (18) of an operating handle; and (iii) spring-loaded play-reducing means associated ith at least one face (20) of the polygonal aperture (16) to reduce any play between the spindle (18) and the side faces of the aperture (16), characterised in that the play-reducing means comprises a spring-loaded ball bearing (22).

2. A door lock mechanism according to claim 1, wherein the follower (14) includes a radial bore (24) extending from a face (20) of the aperture (16) in a radially outwards direction, the spring-loaded ball bearing (22) being mounted in the radial bore (24).

3. A door lock mechanism according to claim 2, wherein the ball bearing (22) comprises a helical spring (26) positioned in the radial bore (24), a ball support cup (28) urged by the helical spring (26) in a radially inwards direction and supporting a bearing ball (30) which partly protrudes from the bore (24) into the aperture (16).

4. A door lock mechanism according to claim 2 or3, wherein the radial bore (24) is a through bore (24), the radially outer end of which is closed by a removeable plug (32)

5. A door lock mechanism according to claim 4, wherein the removable closing plug (32) is in the form of a screw.

6. A door lock mechanism according to any one of claims 1 to 5, wherein the aperture (16) has the shape of a regular polygon.

7. A door lock mechanism according to any one of claims 1 to 6, wherein the aperture (16) has an even number of side faces.

8. A door lock mechanism according to any one of claims 1 to 7, wherein the play-reducing means is associated with only one face (20) of the aperture (16).

9. A door lock mechanism and associated operating handle comprising: (i) a latch bolt (12); (ii) a rotatable follower (14) in operative association with the latch bolt (12), the follower (14) having a polygonal aperture (16) (iii) an operating handle including a polygonal cross-section spindle (18) having the same general shape as that of the follower aperture (16) but being dimensionally smaller to allow assembly of the spindle (18) in the follower aperture (16); and (iv) spring-loaded play-reducing means associated with at least one face (20) of the polygonal aperture (16) to reduce any play between the spindle (18) and the side faces of the aperture (16), characterised in that the play-reducing means comprises a spring-loaded ball bearing (22).

10. A door lock mechanism and associated operating handle according to claim 9, wherein the linear dimensions of the spindle (18) cross-section are between 98.5% and 99.5% of the corresponding dimensions of the follower aperture (16).