GB2198778A

GB2198778A - Door catch assembly

Info

Publication number: GB2198778A
Application number: GB08629143A
Authority: GB
Inventors: George Noel Crowther
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-12-05
Filing date: 1986-12-05
Publication date: 1988-06-22
Anticipated expiration: 2006-12-05
Also published as: GB2198778B; GB8629143D0

Abstract

A catch assembly for a cupboard door comprises a pin 16 on the door and a catch 14 on the frame. The catch consists of an annular housing 28 containing a coil spring 29 in a circular configuration. The pin has a free end portion 17 which is adapted to enter the aperture 44 defined by the spring, followed by a portion of reduced diameter 18. Entry of the free end portion of the pin expands the circular coil spring and further movement of the pin causes the spring to retract over the portion of reduced diameter 18 to retain the assembly in the closed position. The housing 28 may be floatingly mounted in a support 26 to provide a degree of self-alignment. <IMAGE>

Description

DOOR CATCH ASSEMBLY This invention relates to a catch assembly for a pair of closure members such as a door and frame, and more particularly to a simplified form of catch assembly for use with cabinet doors and doors for domestic appliances such as ovens.

Door catch assemblies are known in which a pin on one closure member (usually the door) is received and frictionally retained in a catch on the other closure member (usually the frame). Such catch assemblies are most commonly employed with domestic appliances such as ovens and dishwashers.

Usually the catch on the frame comprises a pair of rollers which are biased by a leaf or compression spring towards each other, and the pin on the door is tapered so that it can be pushed into the gap between the rollers against the pressure of the leaf or compression spring.

The pin is formed with a portion of reduced diameter which is engaged by the rollers when the door is in the fully closed position.

Such catches are effective and reliable but are relatively expensive to manufacture.

The present invention provides a catch assembly for a pair of closure members which is equally effective and reliable and which is less expensive to manufacture than these known catches. Embodiments of the invention also have a number of advantages, as will be described herein.

According to the present invention, a catch assembly for a pair of closure members comprises pin means for securing to one closure member, and catch means adapted to receive and frictionally retain said pin means for securing to the other closure member, wherein the catch means comprises a housing containing coil spring means disposed in a circular configuration; the housing having an opening therein through which the pin can enter the housing and pass into the aperture defined by the coil spring, and the pin means comprises a free end portion of larger diameter than the aperture followed by a portion of reduced diameter whereby the coil spring means is operable to expand radially to allow the free end portion of the pin means to pass through the aperture; and wherein the pin means is frictionally retained in the catch means by engagement of the coil spring means over the portion of reduced diameter.

A number of advantages stem from the use of coil spring means in a circular configuration in place of the previous arrangement of spring-loaded rollers. In particular, the use of coil spring means results in the catch assembly being substantially cheaper and easier to manufacture.

Suitably, the pin means is tapered to facilitate entry into the aperture, and in one embodiment of the invention the housing for the coil spring is frictionally retained in a support which is intended to be secured to the respective closure member, the housing being movable relative to the support within predetermined limits whereby the pin means is operable to adjust the position of the housing relative to the support when the pin means enters the housing.

This embodiment provides an important advantage over known catch assemblies of this kind in that the catch can be made self-centering within certain limits. This means that slight errors in assembly of the door and frame and/or a mis-alignment of the catch means relative to the pin means can be compensated without any separate adjustment.

The tapered pin means simply engages the opening of the housing and draws the housing into correct axial alignment when the door is closed.

Suitably the housing is annular or substantially annular and the coil spring means is disposed within the housing with a degree of radial free play to facilitate radial expansion during entry of the pin means into the aperture. This avoids substantial deformation of the coil spring which would occur if no radial expansion of the circular configuration thereof was possible. Furthermore, in an alternative arrangement, a circular abutment is provided on a radial wall of the annular housing which is operable to restrict radial expansion of the spring means in one direction. The presence of this abutment increases the force required to deform the spring means and enables ne catch to be designed such that the force required for entry of the pin means into the aperture is greater or lesser than the force required for withdrawal of the pin means from the aperture.This arrangement is not possible with prior art catches.

In order that the invention may be more fully understood, embodiments in accordance therewith will now be described by way of example with reference to the accompanying drawings in which: Figs. la and lb show sections through a door and frame fitted with a catch assembly according to the invention, respectively in the open and closed position; Figs. 2a and 2b show respectively front and side elevations of the support member spring housing; Figs. 3a and 3b show cross-sectional views of the spring housing; Figs. 4a and 4b illustrate the coil spring means accommodated within the housing of Figs 3a and 3b; Figs. 5a and 5b are elevation and cross-sectional views respectively of an alternative form of housing made of plastics material, Fig. 5a comprising an elevation in the direction of arrow V in Fig. 5b; and Figs. 6a and 6b show elevation and cross-sectional views respectively of an alternative form of support moulded from plastics material.

Reffering to the drawings, Figs. la and ib show a pair of closure members 10 and 11 which in this case comprise a frame 10 and door 11.

Fig. la shows the door in an open position, and Fig. lb shows the door in a closed position.

The catch assembly according to the invention comprises pin means 12 on the door 11 and catch means 14 on the frame 10. It will be appreciated that in some applications these components may be transposed, i.e. the pin means may be mounted on the frame and the catch means on the door.

In this embodiment the door 11 and frame 10 are parts of a domestic oven assembly, but it will be appreciated that the invention finds many applications where simple forms of door catch are required.

Pin means 12 comprises a spigot 15: formed with a tapered nose portion 17 followed by a portion 18 of reduced diameter. Spigot is has at its end remote from nose portion 17 a threaded portion 19 which extends through door 11 and which engages handle 20. Pin means 12 is preferably made from a material such as stainless steel although in some applications it may be moulded from a hard plastics material such as nylon.

Catch means 14 is mounted on the opposite side of frame member 10 to door 11, i.e. inside the frame, and is substantially aligned with hole 25 provided in frame member 10 for entry of pin means 12. Catch means 14 generally comprises support member 26 which is illustrated in more detail in Figs. 2a and 2b, housing 28, illustrated in more detail in Figs. 3a and 3b, and spring means 29 illustrated in more detail in Figs. 4a and 4b.

Support 26 is stamped out and shaped from thin spring steel sheet such as 0.018 inch (0.46mm) carbon steel and comprises a base portion 30 from which is cut and bent out arms 31, 32 which have turned over ends 33 forming a clasp for receiving housing 28. Base 30 is provided with holes 34 by which the support 26 is secured to frame member 10 by self-tapping screws 35. Base 30 is also provided with tangs 38 which are cut and bent out of the plane of the base towards arms 31, 32 and which serve to retain housing 28 within the support after assembly.

In another embodiment, (not shown) the tangs 38 are replaced by a circular ridge in the base 30 projecting in the same direction.

Housing 28 in generally annular and is formed'in this embodiment from 0.028 inch (0.71mm) mild steel. The housing is fitted into support 26 by pushing it between arms 31, 32 until its periphery passes between tangs 38. The diameter of housing 28 is such that it is retained in position by the edges of tangs 38 but with some free play, its movement being controlled by the spring pressure of arms 31, 32. The support 26 is designed to provide approximately 1/16 inch (1.59mm) of movement radially from a central position.

The annular housing 28 defines openings 50, 51 of larger diameter than the diameter of spigot 16.

Disposed within housing 28 is coil spring 29 which initially comprises (Fig. 4a) a major portion 40 followed by a portion of reduced diameter 41. Coil spring 29 is formed into its circular configuration by insertion of reduced diameter portion 41 into the open end of portion 40, the diameter of portion 41 being such that once inserted, it cannot readily be removed (Fig. 4b). In its circular configuration, coil spring 29 defines a circular aperture 44.

Coil spring 29 is fitted into housing 28 by deforming the spring and forcing it through opening 50; once it is inserted into the annular housing, as shown in Figs. la and lb, it cannot be removed. The diameter of aperture 44 of the closed circular spring 29 in its normal condition is approximately equal to that of the reduced diameter portion 18 of spigot 16.

Operation of the catch is simple and will be readily apparent from the drawings.

Movement of door 11 towards the closed position causes'spigot 16 to enter hole 25 in frame member 10 and the tapered portion 17 of spigot 16 engages the edge of aperture 51. As shown in Fig. la, due to poor fitting the housing 28 is not co-axial with pin 12 but as housing 28 has some freedom of movement within support 26, movement of pin 12 into opening 51 draws the housing 28 into the correct position, as shown in Fig. lb; the pin 12 then follows through into the spring aperture 44. Aperture 44 is of smaller diameter than the spigot 16, and nose 17 expands spring 29 outwardly, the spring 29 having sufficient free play in housing 28 to do this without substantial deformation of the individual coils of the spring.As the door passes into the closed position, nose 17 of spigot 16 passes beyond spring 29 and the spring contracts into the reduced diameter portion 18 of spigot 16, to grip the spigot in this position. The door is thereby retained in the closed position, opening being accomplished by traction on handle 20 to cause the spring 29 to deform outwardly and thereby to release spigot 16. Spring 29 rotates during expansion and contraction in order to reduce the friction present in the catch assembly.

An important optional feature of the invention is shown in Fig. 3b.

In this arrangement the front wall 52 of annular housing 28 is formed with an annular abutment 54 which is stamped out from the housing during manufacture. This abutment 54 restricts radially outwardly movement of spring 29 during withdrawal of pin 12, thus increasing the load required to open the door 11 compared with the load required to close the door. This is a useful feature as it makes it possible to vary the opening and closing loads of the catch assembly such that only a small load, e.g. 31b (1.35kg) is required to close the door whereas a higher load e.g. 25 lb (11.3kg) is required to open the door. Such an arrangment is particularly advantageous with certain appliances such as ovens and dishwashers where higher opening loads are desirable.

Fig. 5a and 5b show and alternative embodiment of housing 60 which is moulded in one piece from a material such a glass-filled nylon. The housing 60 comprises an annular body part 61 connected at 53 to a circular lid part 62, the two parts being moulded in a single operation. A locating ridge 64 is moulded into one wall of lid part 62 and when the spring 29 is disposed in body part 61 and lid 62 closed, this locating projection serves to lock the lid part in position. Lid part 62 is formed with an aperture 66 and a circumferential bead 67 extends around this aperture. This bead is adapted to enter the central aperture 75 of moulded plastics support member 70 shown in Fig. 6a and 6b, as will be described. A circular recess 65 provides restriction of radial expansion of the spring as the pin is withdrawn.

Support member 70 is moulded from the same material as housing 60 and comprises a base portion 71 and an annular boss 72 which is operable to engage housing 60. Inner surfaces of boss 72 are formed with abutment sections 73 which carry out the same function as tangs 38 of metal support 26, i.e. they frictionally retain housing 60 in position when it is pushed into the clasp part formed by boss 72. The abutment sections 73 also register around the retaining circumferential bead 67 to prevent the spring housing 60 moving beyond the engagement range of the spigot.

Claims

CLAIMS:

A A catch assembly for a pair of closure members, comprising pin means for securing to one closure member and catch means adapted to receive and frictionally retain said pin means for securing to the other closure member; said catch means comprising a housing containing coil spring means disposed in a circular configuration; the housing having an opening therein through which the pin can enter the housing and pass into the aperture defined by the coil spring, and said pin means comprising a free end portion of larger diameter than said aperture followed by a portion of reduced diameter whereby said coil spring means is operable to expand to allow the free end portion of the pin means to pass through said aperture; and said pin means is frictionally retained in said catch means by engagement of said coil spring means over said portion of reduced diameter.
2. A catch assembly as claimed in Claim 1, wherein the free end portion of the pin means is tapered to facilitate entry into said housing.
3. A catch assembly as claimed in Claim 2, wherein said housing is frictionally retained in a support adapted to be secured to said other closure member and is movable relative thereto within predetermined limits, whereby said pin means is adapted to adjust the position of said housing relative to the support when said pin means enters said aperture.
4. A catch assembly as claimed in any one of the preceding claims, wherein said housing is annular and said coil spring means is disposed within said housing with radial free play to facilitate radial expansion thereof.
5. A catch assembly as claimed in Claim 5, wherein one radial wall of said annular housing comprises a circular abutment for said coil spring means operable to restrict radial expansion of said spring means in one direction, whereby the force required for entry of said pin means into said aperture may be greater or lesser than the force required for withdrawal of the pin means from said aperture.
6. A catch assembly for a pair of closure members, substantially as hereinbefore descirbed with reference to the accompanying darwings.