GB2156418A - A magnetic door catch - Google Patents

Abstract

A magnetic door catch includes a member for mounting to a door of an appliance, such as an oven, the member consisting of a housing 1 accommodating a permanent magnet 7 sandwiched between two pole pieces 8, 9 with portions 10 protruding from the top wall 2 of housing 1. The permanent magnet and pole pieces are pivotally retained within the housing 1 by means of a pin 11 and portions 10 are attracted magnetically to a striking plate 15 mounted to a door frame of the appliance. A spring 20 consists of a straight part 23, which is located parallel to, and urged against, door mount 13, 14 to retain the housing 1 within mount 13, 14, and a crook-slipped part 24, which extends over pivotting pin 11 so that its curved end 27 is urged against pin 11, to provide resilient movement of the pole pieces within housing 1. <IMAGE>

Description

SPECIFICATION A magnetic door catch This invention relates to a magnetic door catch and in particular, though not exclusively, to one suitable for use in a domestic appliance, such as an oven.

A magnetic door catch typically comprises two main components, a first component, which is mounted either to a door or to a frame therefor, including a housing accommodating, in a pivotal position, a magnetic assembly including a permanent magnet disposed between two pole pieces, and a second component mounted to either the frame or the door as appropriate. The second component usually comprises a ferromagnetic striking plate which is disposed so as to latch with the first component, to which it is magnetically attracted, when the door is closed.

A prior proposal has included a single spring member accommodated substantially within the housing of the first component and comprising a middle portion which extends over the pivotal mount of the magnetic assembly, so as to permit some resilient movement of the assembly within the housing, and two end portions biassed respectively against the mount of the first component, so as to aid in retaining the first component within the mount.

However, this proposed type of door catch may lead to a number of operational problems and may require a relatively large, heavy-duty spring member of the proposed configuration to alleviate such problems. A major advantage of a door catch of this type is that its structure enables it to be made less complex and more compact than other known types of magnetic door catch, but it can be envisaged that the use of large, heavy-duty members would substantially reduce the desirable compactness of the door catch.

It is therefore an object of the present invention to provide an improved magnetic door catch of the above-mentioned type.

According to the invention there is provided a magnetic door catch for a door and frame assembly comprising a first member for mounting on one of said door and frame and a second member for mounting on the other of said door and frame, said first member consisting of a magnetic assembly substantially accommodated within a housing, at least one magnetic portion of said magnetic assembly protruding from a side of said housing, said portion or portions being disposed so as to attract magnetically said second member and to latch therewith, pivotting means for pivotally retaining said magnetic assembly within said housing, and a resilient member for retaining said first member, when mounted, within said mount and for providing resilient movement of said magnetic assembly within said housing, said resilient member comprising a first part which, when said first member is mounted, extends in a direction substantially parallel to said mount and is arranged to be urged theretowards and a second generally crook-shaped part connected to one end of said first part and arranged to extend over, and be urged against, said pivotting means.

Preferably the first part of the resilient member extends substantially parallel to side walls of the housing and substantially beyond opposing ends of the housing.

The first part of the resilient member is also preferably disposed outside of the housing and the second part is preferably disposed within the housing.

The door catch preferably includes first and second resilient members held in a substantially parallel disposition relative to each other by a connecting member.

The invention will now be further described by way of example only with reference to the accompanying drawings, wherein: Figure 1 shows a plan view of a prior proposal of a magnetic door catch, Figure 2 shows a side view of said prior proposal, Figure 3 shows an end view of said prior proposal, Figure 4 shows a part of one embodiment of the present invention prior to assembly, Figure 5 shows a preferred embodiment of the invention when assembled, and Figure 6 shows a view in direction "A" in Figure 5.

Figure 1 shows a first member of a prior proposal of a magnetic door catch, which is preferably mounted to a door of an appliance, such as an oven. The first member consists of a housing, shown generally at 1, which is preferably made of stainless steel, having a top wall 2 and opposing side walls 3 and 4, ends 5 and 6 and the underside of the housing 1 being open.

A magnetic assembly, accommodated within the housing 1, comprises a permanent magnet 7 having pole pieces 8 and 9, made preferably of mild steel, disposed either side thereof. Each of the pole pieces 8 and 9 have protruding portions, such as at 10, which protrude from within the housing 1 through apertures, such as at 16, in the top wall 2.

These protruding portions 10 of the pole pieces 8 and 9 are disposed so as to attract magnetically a second member, in the form of a striking plate (not shown in Figure 1), which is preferably mounted to a door frame of the oven.

The permanent magnet 7 and the pole pieces 8 and 9 are pivotally retained within the housing 1 by a pin 11, which extends through holes in the pole pieces and a groove (not shown in Figure 1) formed in the permanent magnet, and is fixed to the side walls 3 and 4 of the housing 1.

The pin 11 permits the magnet 7 and pole pieces 8 and 9 to pivot, about the pin 11, within the housing 1 in substantially all directions, the apertures 16 in the top wall 2 being sufficiently large to allow this pivotal movement of the protruding portions 10.

A wire spring 12, preferably made of stainless steel, extends over the pin 11 and along the outer sides of each pole piece 8 and 9, and urges the housing 1 against its door mount, shown partly at 13 and 14, at either end therof.

Figure 2 shows a view of the side wall 4, shown in Figure 1, and indicates more clearly the shape of the wire spring 12, which is shaped to fit over the pin 11 and to urge the housing 1 against the door mount, 13 and 14.

The above-mentioned striking plate, which is preferably mounted to the door frame, is shown at 15.

It can also be seen from Figure 2 that the pin 11 extends through groove 17 in the permanent magnet, whilst also extending through holes in the pole pieces, so as to retain the magnet and pole pieces within the housing 1.

The wire spring 12 also permits resilient movement of the magnet 7 and pole pieces 8 and 9 in a direction substantially orthogonal to the surface of the top wall 2, so that when the striking plate 15 and protruding portions 10 are latched together, the door can be parted from the frame before the protruding portions unlatch from the striker plate, the protruding portions extending further from the top wall 2 against the action of the wire spring 12, which subsequently pulls the protruding portions 10 back to their normal postion, once they have unlatched from the striking plate 15.

Figure 3 shows a view of end 6 of the housing 1, indicating the pole pieces 8 and 9, which are disposed either side of the permanent magnet 7 and through which the pin 11 extends. The end of the wire spring 12 is shown, urging the housing 1 against the door mount 14, and protruding portions 10 are shown extending from the housing 1 through the apertures provided in the top wall 2.

It may be preferable to provide rubber pads (not shown) around the door mount 13 and 14, so as to cushion the housing 1, thereby softening the impact thereof on the mount, during latching of the door to the frame.

It may also be preferable to incorporate a simple wire or leaf spring, which may be formed from stainless steel, either between the pole pieces 10 above the top wall 2 or behind the magnet assembly within the housing 1, so as to urge the pole pieces 10 as far outwardly from the top wall 2 as possible. To accommodate the wire or leaf spring, it may be necessary to modify the shape of the pole piece 10, the housing 1 and/or the pin 11.

The retention force of the door catch, may of course be determined by correct dimensioning of the protruding portions 10 of the pole pieces 8 and 9.

However, for efficient operation of the previously proposed door catch shown in Figures 1 to 3, spring 12 is required to be relatively large and of a substantially heavy-duty type, the wire from which it is formed being of a relatively large gauge, thereby foregoing the structural advantages, such as compactness, of this type of door catch.

Figures 4 to 6, wherein like parts are labelled with like reference numerals with respect to Figures 1 to 3, show one embodiment of the present invention, which substantially alleviates the operational and structural problems of the prior proposal.

Figure 4 shows a preferred configuration of a resilient member, such as a spring 20 consisting of two substantially identical members 21 and 22, each comprising a substantially straight part 23 and a generally crook-shaped part 24 connected to one end 25 of the straight part 23. The two members 21 and 22 are connected at end 26 by member 28, so as to hold each member in a substantially parallel position relative to each other.

Figures 5 and 6 show a preferred location of the spring 20 relative to the housing 1 of the first member of the door catch. It can be seen that part 23 of the spring 20 is located substantially parallel to, and urged against, the door mount 13, 14, when the first member is mounted therewithin, so as to retain the housing 1 within the mount 13, 14.

The crook-shaped part 24 extends over the pivotting pin 11 so that its cured end 27 is urged against the pin 11.

The straight part 23 extends parallel to side walls 3, 4 of housing 1 and beyond the ends 5, 6 of the housing. It can also be seen from Figures 5 and 6 that part 23 is preferably disposed along the outer surface of side walls 3, 4 of the housing 1 and that the crook-shaped part 24 is disposed within the housing 1 between the inner surface of side walls 3, 4 and the outer surface of the pole pieces 8, 9.

This preferred disposition of the spring 20 aids in assembly of the first member of the door catch during manufacture thereof.

The present configuration of the spring 20 is advantageous over the previously proposed spring configuration because it provides substantially more stability and leverage both for retaining the housing within its mount and for providing sufficient resilient movement of the magnetic assembly mounted within the housing. As a consequence of using this advantageous configuration, the spring can be formed from wire of a substantially smaller gauge than hitherto, thereby enhancing the compact nature of this type of magnetic door catch.

Claims (11)

1. A magnetic door catch for a door and frame assembly comprising a first member for mounting on one of said door and frame and a second member for mounting on the other of said door and frame, said first member consisting of a magnetic assembly substantially accommodated within a housing, at least one magnetic portion of said magnetic assembly protruding from a side of said housing, said portion or portions being disposed so as to attract magnetically said second member and to latch therewith, pivotting means for pivotally retaining said magnetic assembly within said housing, and a resilient member for retaining said first member, when mounted, within said mount and for providing resilient movement of said magnetic assembly within said housing, said resilient member comprising a first part, which, when said first member is mounted, extends in a direction substantially parallel to said mount and is arranged to be urged theretowards and a second generally crook-shaped part connected to one end of said first part and arranged to extend over, and be urged against, said pivotting means.

2. A door catch as claimed in Claim 1 wherein said first part of said resilient member extends substantially parallel to a side wall of said housing and substantially beyond opposing ends of said housing.

3. A door catch as claimed in Claim 1 or 2 wherein said first part of said resilient member is disposed outside of said housing.

4. A door catch as claimed in any preceding claim wherein said second part is disposed within said housing.

5. A door catch as claimed in any preceding claim and including first and second resilient members held in a substantially parallel disposition relative to each other by a connecting member.

6. A door catch as claimed in any preceding Claim wherein said pivotting means consists of a pin which is fixed, either end thereof, to respective opposing side walls of said housing, said pin extending across the inner space of said housing, said magnetic assembly being pivotally mounted on the pin within said housing.

7. A door catch as claimed in any preceding claim wherein said magnetic assembly consists of a permanent magnet disposed between first and second pole pieces, said at least one protruding portion being part of said pole pieces.

8. A door catch as claimed in preceding Claim wherein said resilient member consists of a wire spring made of stainless steel.

9. A door catch as claimed in any preceding claim wherein said second member consists of a ferromagnetic striking plate.

10. A door catch as claimed in any preceding claim and including means for cushioning said housing within said mount.

11. A magnetic door catch substantially as herein described with reference to Figures 4 to 6 of the accompanying drawings.