GB2281099A - Self-closing door hinge - Google Patents

Abstract

A self-closing door hinge comprises two co-axial cam elements 14, 16 urged together by a spring. Each element 14, 16 has two cam edges (46, 50 and 52, 54 Fig. 2) which are diametrically related and axially spaced with dwell portions (48, 54 Fig. 2) between them. One part 16 is angularly fast with a spindle 16 connected to an arm 22. As the arm is turned cam element 16 will axially displace the other cam element 14. After the door is turned through about 90 DEG the dwell portions are reached. In this position the spring will not act to return the door to the closed position. Further angular movement of the door will result in further axial displacement of the other cam element 14 causing the spring to again act to close the door. At the dwell position there may be a slight return axial movement of the other cam element 14. <IMAGE>

Description

HINGE ASSEMBLY This invention relates to hinge assemblies especially for use on refrigerators, freezers, storage cabinets, cold rooms and the like and especially where self-closing movement is desirable.

Conventional arrangements have employed cams displaced by the opening movement and providing an axial displacement for stressing a closing spring. This has resulted in substantial wear to the cam which has often had a short life as a consequence.

The object of the invention is to provide improvements.

According to the invention a hinge comprises a pair of coaxial parts which are relatively angularly movable, with cooperating cam edges for causing axial displacement of one part relative to the other when so moved, and is characterised in that both parts have a plurality of said cam edges whereby applied loads are distributed.

Preferably the cam edges include dwell portions in which incremental angular movement causes no further increase in axial displacement. In an even more preferred version the dwell portion allows a slight return axial movement.

Conveniently the plurality comprises a pair of cam edges which are diametrically related but axially spaced on each of the parts. Hence all four cam edges may be in engagement, in two pairs of engaged faces when the parts are at minimum axial separation and this has the advantage of allowing a first axially located cam edge on one part to move across a first axially located cam edge on the other part to the dwell portion and at the same time the two second axially located parts likewise traverse one another to the dwell portion. Thereafter the first cam edge on one par moves across the second axially located cam edge on the other part during continued movement in the same angular direction.

The arrangement may be such that the angular movement effectively amounts to about 90 degrees before the dwell position, a few degrees in the dwell position and with a possible movement of some extent beyond the dwell position. Applied to a cold room door for example this means that the door may be opened for up to 90 degree movement and at any time when released during this 90 degrees may be spring closed. After the 90 degree movement and in the dwell position the slight axial return of the hinge parts holds the door open in the 90 degree position. Any attempt to move the door further than 90 degrees is permitted but with increasing loading on the springs.

Conveniently the two hinge parts are journalled on a common hinge pin and contained in a tubular housing with a spring wound about the pin. For example by using a compression spring, one of the parts may be axially displaced along the housing by the angular movement and compress the spring. Alternatively a torsion spring or a tension spring could be used. The other of the parts may be fixed against rotation for example by means of radially extending flanges received in axially extending slots in the housing. Alternatively, one part may be made integral with or angularly fast with the housing.

One embodiment of the invention is now described with reference to the accompanying drawings wherein: Figure 1 is a part-sectional and part-exploded diagrammatic view of a preferred embodiment; Figure 2 shows components of the same in five different angular positions indicated by the reference letters A-F., Figure 3 is a sectional elevation of the assembly; and Figure 4 is a plan view of the same.

Referring to the drawings, hinge pin 10 (Fig. 3) is journalled at its lower end in a bore in casing 12 and extends through a pair of cam portions 14 16 located endto-end in the casing. The opposite end 18 of the spindle has flats 20 or like means for making it angularly fast to a first arm 22 (Fig. 1). Hence, turning the arm 22 turns the hinge pin.

The casing 12 is fast with a second arm 24. Spring 26 is, in this embodiment, a helical compression spring trapped between the bottom end of the casing and the cam parts, urging the two cam parts together.

One cam part 14 is angularly fast with the casing for example by means of an external shaping on the cam such as the ribs indicated by the reference 30, Fig.1, cooperating with complementary grooves 32 in the casing.

This allows the cam part to move axially but not angularly. The second cam part 16 is fast with the hinge pin for example by means of a non-circular recess in the cam part 16 cooperating with a like shoulder on the hinge pin indicated by the reference 34, Fig.3. This effectively makes the cam part 16 axially stationary but angularly free for movement with the hinge pin and the one arm.

The spring drives the cam parts to the axially minimum length position as seen in Figure 2A, which is the 0 degree angular position of the one part relative to the other, and hence of the one arm relative to the other. B shows the position where the one arm has turned through 60 degs. relative to the other, C shows the 90 degree position and so on.

Figure also shows the cam faces in more detail. The lower cam part 14 has a first cam face or edge 46 which extends up to a dwell face 48 extending in a plane normal to the hinge axis, and a second cam edge 50 extends upwardly therefrom.

The upper cam part 16 has generally complementary cam edges 52, 54, 56, except that the dwell portion 54 is slightly recessed as shown, so that there is a slight axial return of the parts in passing from the position C to the position D in Figure 2 which results in the door fitted with the hinge being held open and not returned by the spring. However, if the parts are further turned for example to the position E, and then released, the spring will return the parts at least to the D position, and possibly if there is sufficient momentum continue to close the door.

Claims (8)

1. A hinge comprising a pair of coaxial parts which are relatively angularly movable, with cooperating cam edges for causing axial displacement of one par relative to the other when so moved, and characterised in that both parts have a plurality of said cam edges whereby applied loads are distributed.

2. A hinge as claimed in Claim 1 wherein the cam edges include dwell portions so that incremental angular movement causes no further increase in axial displacement when said dwell portions are engaged.

3. A hinge as claimed in Claim 2 wherein the dwell portions are arranged so as to cause a slight return axial movement and so as to enable a door provided with the hinge to be held in an open condition when said parts are engaged.

4. A hinge as claimed in any preceding claim wherein the plurality of cam edges comprise a pair of cam edges which are diametrically related but axially spaced on each of the two coaxial parts.

5. A hinge as claimed in Claim 4 wherein the arrangement is such that angular movement amounts to about 90 degs. before dwell position, a few degrees in the dwell position and an additional movement beyond the dwell position.

6. A hinge as claimed in any preceding claim wherein the said coaxial parts are located in a common casing, one of the parts is angularly fast but axially free in the casing and the other is angularly free and axially fast in the casing.

7. A hinge as claimed in Claim 6 wherein the two parts are urged together by a coaxial compression spring trapped in the casing.

8. A hinge substantially as hereinbefore described with reference to the accompanying drawings.