US3450851A - Door latch mechanism - Google Patents

Description

June 7, 1969 I; I I r 5 f 9 llmmm Mia I RICHARD PERL United States Patent 3,450,851 DOOR LATCH MECHANISM Richard L. Perl, Mansfield, Ohio, assignor to The Tappan Company, Mansfield, Ohio, a corporation of Ohio Filed Apr. 13, 1966, Ser. No. 542,391 Int. Cl. HOlh 13/52 US. Cl. 200-61.68 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates as indicated to a latch mechanism for doors and particularly doors such as those used in automatic dishwashers which are required to exert a sealing force when closed, usually against a gasket or other deformable sealing element.

It is a primary object of the invention to provide a door latch mechanism which has a superior locking action and yet can be conveniently and easily released for opening of the door.

Another object is to provide such latch mechanism having a push button release, with this form of actuator in a front loading automatic dishwasher, for example, having the advantages of minimum and regular projection at the front of the door, extremely convenient location and manipulation, and simple clean design from the standpoint of appearance of the appliance.

It is also an object of the invention to provide a latch for dishwasher doors and the like which is relatively inexpensive and readily incorporated in existing designs for such machines.

It is a still further object to provide latch mechanism for a door including electric switch actuating means to provide a related switching function, for example, to interrupt operation of an automatic dishwasher responsive to opening of the door.

It is further desirable in such a dishwasher that the such switch control be somewhat anticipatory of actual opening of the door to provide at least a brief interval for decay of the particular operating condition which may be interrupted, such as a water spray, and it is still another object of this invention to incorporate such an anticipatory switching function in the door latch mech anism to the end that the interruption is effected almost immediately upon initial movement of the release member and before full disengagement of the latching mechanism.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a front elevation of an automatic dishwasher the door of which is equipped with latching mechanism in accordance with the present invention;

3,450,851 Patented June 17, 1969 FIG. 2 is a fragmented sectional view of the portion of the machine in which the latch is located, the plane being indicated by the line 2-2 in FIG. 1;

FIG. 3 is a further sectional view taken on the plane of the line 3--3 in FIG. 2; and

FIG. 4 is a fragmentary top view of the mechanism with parts broken away for convenience of illustration.

Referring now to the drawings in detail, the automatic dishwasher shown in FIG. 1 is of conventional construction apart from the door latch mechanism to be described, with this machine having a front door 10 hinged at the bottom to move between the vertical closed condition illustrated and a substantially open horizontal position. The door has a decoratively formed top strip 11 projecting forwardly and downwardly with a free rolled lower edge 12 and serving as a handle for the door. The door of this machine is also provided with an upper control panel 13 just below the handle portion 12, with knobs 1'4 and push buttons 15 for scheduling the automatic operation in conventional manner.

As best shown in FIG. 2, the tub 16 of the dishwasher has a front boundary wall portion 17 in a vertical plane, with this portion extending continuously about the sides and top and opposed to the peripheral portion 18 of the door in accordance with conventional construction. As is also conventional, the inner liner 19 of the door projects inwardly from such peripheral portion to enter the tub and sealingly engage an elastomeric gasket 20 fixed to the tub interior and also extending continuously about the sides and top.

A specially formed strike is fixed to the tub at the top center of the framing wall portion 17, with a stem 21 shown threaded in the illustrated embodiment penetrating this wall portion and being locked by an exterior nut 22 and an interior spring nut 23 acting oppositely against the wall portion. This strike has a relatively flattened substantially triangular head 24 at its outer end, with such head being horizontal and symmetrically related to the stem as shown to have a point foremost and base shoulders 25 projecting laterally to the respective sides of the contiguous stem portion 26. The edges of this stern portion 26 converge slightly outwardly to the junctures with the base shoulders 25.

The keeper assembly of the latch is mounted within the top interior of the door on a bracket 27 suitably affiXed to the inner door liner. This bracket is cut and bent or otherwise formed to provide a top edge flange 28 projecting forwardly, a similarly projecting middle or inter-mediate flange 29 at a lower elevation, and a lower body section 30 which is displaced forwardly relative to the upper section and has a small forward bottom flange 31. A wire hairpin spring is supported on the bracket 27 in the inverted condition shown in the drawing, with the closed end or loop 32 resting on the bottom flange 31 of the bracket and against its lower body section 30. This closed end portion of the spring is restrained by small angles 33 struck from the body section to project forwardly at two opposite points inside the loop and then laterally over the spring at these portions, so that the thus restrained spring is free for expansion or spreading of its two arms 34 which are normally substantially parallel over their major extents.

The intermediate bracket flange 29 has a pair of aligned slots in its side edges and the arms 34 of the spring extend upwardly respectively through these slots. A roller 35 is applied to the end of each arm of the flange, so that there are two such rollers normally held in substantially parallel vertical relation and spaced slightly respectively to the sides of the axis of the strike in the approach of the latter.

The length or vertical dimension of the rollers 35 is appreciably greater than the thickness of the strike head 24 and the arrangement is such that the latter is directed approximately half way between the tops and bottoms of the rollers. It will be clear that bringing the door from an open to the closed condition advances the spring roller keeper assembly on the strike, an opening 36 of course being provided in the inner door liner 19 for penetration of the door by the strike. The strike head 24 enters the normal small space between the rollers 35 and, with continued closing movement, the relatively diverging side edges of the head force the rollers apart against the tension of the spring arms 34 until the rollers pass over the base corners 25 and are snapped in against the stem portion 26 of-the strike behind these corners or shoulders. This is the fully closed and latched condition of the door illustrated in the drawing, and it will be appreciated that the projection of the strike is adjusted to provide the proper amount of relative travel thus to latch the strike with the desired pressure exerted by the door against the sealing gasket. It has been found that the shoulders of the strike head should preferably be normal or at right angles to the stem axis for the degree of restraint desired in an application of the latch mechanism to such a dishwasher door.

The release of the latch is effected by a push button member, designated generally by reference numeral 37, disposed horizontally to extend from the spring rollers 35 forwardly through an opening 38 in the front wall of the door handle 11, with the exposed outer end 39 of such member thereby being conveniently available to the housewife or user, for example, to be depressed by the thumb of the same hand of the user which grasps the handle to pull the door open. This member, which .can be most easily made of molded plastic, has an intermediate body section 40 just behind the handle wall of larger cross section than the projecting outer end 39 and the opening 38 through which the latter extends, so that there is a resulting shoulder which serves as a stop precluding withdrawal of the member from the door. Inwardly of this section, the member 37 is formed with similar top and bottom finger extensions 41 of wedge shape which are vertically spaced apart a distance appreciably greater than the vertical dimension of the strike head 24. In the extended condition of the push button member, as shown, the inner ends of the wedging fingers 41 just enter the space between the rollers 35 without exerting any spreading force. The extreme ends of the fingers are sharply tapered and will engage the rollers both above and below the strike the head of which is of course accommodated in the relatively penetrating latched condition by the vertical separation of the fingers. The top and intermediate flanges 28, 29 of the bracket 27 will afford some guiding of the push button, with the fingers 41 respectively closely adjacent the opposed surfaces thereof.

The latch is accordingly actuated to release the door for opening simply by pushing the member 37 in by hand thereby causing the wedging fingers 41 to spread the spring rollers 35 sufiiciently for disengagement with the strike head 24. As the door is pulled open, the rollers 35 of course will move back to the close spaced normal condition immediately upon release of the force on the push button member 37, and this spring return will be seen also to be effective to extend or move outwardly the push button member to its normal full projecting position as shown. The closing of the door is of course accomplished in a swinging movement which aids the forcible closing against the seal without noticeable added demand, and a very film and positively locked closure of the door is provided by the disclosed mechanism.

The dishwasher is preferably also provided with an electric switch control responsive to the opening and closing of the door, and the switch provided for the purpose is shown as contained within a casing 42 which is suitably mounted inside the top portion of the door laterally adjacent the latch mechanism. The switch contact assembly and wiring are conventional, with an actuator in the form of a pin or plunger 43 projecting from one side of the casing under a spring bias as is usual and to be depressed, for example, in this case to close normally open contacts. With this switch connected in appropriate manner in the control circuit for the dishwasher, the operation of the machine can therefore be made dependent upon such actuation.

The switch is provided with an actuating leaf designated 44 generally attached at one end to the switch casing 42 by a pivot 45 and extending over the plunger 43 to engage and operate the same. This leaf is formed of two spring blades 46 and 47 having straight initial lengths which are placed against each other and joined together to form a common section which extends from the end pivot connection beyond the point of engagement with the switch plunger. The blades then separate to provide two distinct free blade sections and the blades are, moreover, of different thickness to exhibit different spring characterisfiics. More particularly, the blade 45 which is relatively to the front is of such thickness that its free section acts as a fairly heavy spring, while the other inner blade 47 is noticeably thinner and thus has a lighter spring action.

The light spring blade 47 is angled as shown to locate its free ends 48 in the path of the strike head 24 to be deflected by the relative advance of the strike in moving to the latched condition in the keeper assembly. In looking down on the assembly as in FIG. 4, wherein the mechanism is fully latched, the strike head 24 has deflected the spring blade 47 from a normal position relatively to the right from that shown and this deflection has produced pivoting of the leaf 44 in a counterclockwise direction and thus against the plunger 43 to depress the same and close the switch contacts to permit the usual machine operation. When the latch is disengaged and the door opened, the return of the freed spring blade 47 allows opening of the switch to disable the machine.

As indicated in the above, it is sometimes desirable to provide an anticipatory switch function for such a door, so that while the closing of the electrical contacts of the switch in the example given is effected upon full engagement of the latch mechanism, the opening of the switch contacts will be responsive to the initial actuation to effect the release of the latch. In the illustrated embodiment of the invention, this feature is provided by the heavier spring blade'46 and its arrangement in engagement with the shoulder at the inner end of the push button member body section 40. Referring again to FIG. 4, it will be apparent that depression of the push button directly acts on the heavy blade 46 and the relation to the lighter blade 47 as noted permits the former to overpower the latter and move the common leaf section sufficiently away from the switch plunger 43 to allow the plunger to open the contacts.

It will also be appreciated that the push button form of release perferred does not detract from the attractive appearance of the dishwasher and, moreover, that the clean simple handle lines remain intact. The release movement is essentially in line and compatible with the door manipulation, with no swinging levers or the like adding both projection and complication of the hand motion required.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described.

I, therefore, particularly point out and distinctly claim as my invention:

1. Latch mechanism for a dishwasher door and the like confronting a framing surface, a strike member on one of said door and surface and keeper means on the other for latching engagement with the strike member in the closed door condition, said strike member having a foremost head portion with rearwardly diverging sides and a rearwardly contiguous body portion of such relatively reduced size as to define laterally spaced shoulders behind and respectively at such sides of the strike member, said keeper means including a pair of detents arranged at the sides of the strike member when the latter advances relative to the keeper means for the latching engagement therewith, said detents being in the form of rollers the axes of which are normally substantially in right angular relation to the strike member, spring means normally holding said rollers at a spacing which is less than the width of the head portion of the strike member at the shoulder defining juncture thereof with the contiguous body portion, the spring means yieldingly permitting the rollers to separate for passage of said head portion and then moving them inwardly behind the shoulders thereof to lock the strike member in the keeper means, and push-button means for forcing the rollers apart when manually actuated sufliciently to permit relative withdrawal of the strike member, said push-button means having spaced wedging finger extensions which engage the end portions of the rollers at both sides of the strike member engagement therewith.

2. In combination with an automatic dishwasher and the like having a tub and a closure therefor, latch means for holding the closure in closed condition against the tub, said latch means comprising a strike on one of the tub and closure and cooperable keeper means on the other, the strike and keeper means being relatively moved into locking interengagement upon full closing of the tub closure, manual release means for disengaging the locked strike and keeper means to permit opening of the closure, switch means mounted on one of the tub and closure for controlling operation of the dishwasher in response to closing and opening of the door, first actuator means operated by the strike for closing the switch and resiliently holding the same closed as a result of such locking interengagement of the strike and keeper means, and second actuator means separate from but operated by said release means for opening the switch in response to initial movement of said release means when operated to disengage the strike and keeper means and before full disengagement thereof, whereby an operating cycle of the dishwasher can automatically be interrupted in anticipation of opening of the tub closure.

3. The combination set forth in claim 2, wherein said release means includes a push-button actuator.

4. The combination set forth in claim 2, wherein said first actuator means is a relatively light first spring arm engaged and deflected by the strike in such relative movement of the same, and the second actuator means is a less flexible second spring arm actuated by the release means to overpower the switch-closing force of said first spring arm and thereby open the switch.

5. The combination set forth in claim 2, wherein the strike has a head of spear form and the keeper means includes spring-biased rollers which are cammed apart by the strike head and engage therebehind to lock the strike.

6. The combination set forth in claim 5, wherein the release means includes spaced fingers which engage the rollers at each side of the strike head when locked and wedge the rollers apart to free the strike.

7. The combination set forth in claim 6, wherein the release means further comprises a push-button actuator.

8. The combination set forth in claim 6, wherein the first actuator means is a relatively light first spring arm engaged and deflected by the strike in such relative movement of the same, and the second actuator means is a less flexible second spring arm actuated by the release means to overpower the switch-closing force of said first spring arm and thereby open the switch.

9. The combination set forth in claim 8, wherein the tub closure 'has a handle, and said release means further comprises a push-button actuator which projects through a portion of said handle.

References Cited UNITED STATES PATENTS 2,824,185 2/1958 Sevey 200-172 X 2,934,074 4/1960 Low 134-58 2,502,607 4/1950 Vinton 292-23 2,605,630 8/1952 Keeler. 2,857,191 10/1958 Buchholtz 292-77 X 2,896,641 7/1959 Kautfman et al.

MARVIN A. CHAMPION, Primary Examiner.

US. Cl. X.R.

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