US3451702A - Latch mechanism - Google Patents

Description

C. H. LITTLE LATCH MECHANISM June 24, 1969 Filed March 14, 1967 Sheet INVENTOR.

CARL H. LITTLE ATTORNEYS United States Patent U.S. Cl. 292-99 4 Claims ABSTRACT OF THE DISCLOSURE Brie summary and background of the invention Prior forms of such latches have proven to be somewhat unsatisfactory and unreliable in operation, either because of failure to properly. secure the door in closed position or to freely release it when desired. Also, such prior latch constructions are unsatisfactory because of mechanical complications involved in their designs, and because of the costs necessarily involved in the manufacture and assembly of their parts.

It is an object of the present invention to provide an improved latch of the type aforesaid which is of mechanically simplified form and which may be relatively inexpensively manufactured to provide a smooth-working, reliable, automatic latch mechanism.

It is another object of the invention to provide an improved latch mechanism as aforesaid wherein the parts are so arranged that in the event of mechanical failure of any part or parts the mechanism will not remain in locked condition.

Still another object is to provide a mechanism as aforesaid wherein the slide-bearing relatively moving parts are of materials providing long-life frictionless operation, whereby smooth working and maintenance-free performance is assured.

Other objects and advantages of the invention will be apparent from the following specification and the accompanying drawing.

In the drawing:

FIG. 1 is a fragmentary vertical sectional view through a cabinet having a vertically swinging cover hingedly mounted thereon, and embodying an automatic latch mechanism of the present invention;

FIG. 2 is a fragmentary sectional view taken as indicated by line 22 of FIG. 1; illustrating by means of broken lines the positions of the latch parts when the cover is being pressed downwardly toward cabinet closing position; and by means of solid lines showing the parts when in cover-holding position;

FIG. 3 corresponds to FIG. 2 but illustrates coaction between the latch parts when the cover is subsequently further depressed to disengage the latch parts;

FIG. 4 corresponds to FIG. 3 but illustrates how (when the cover rises in response to the spring-hinge action) the latch strike resets the latch mechanism to subsequently receive the strike for automatically latching the cover when it is again pressed down into cabinet-closing position;

FIG. 5 is a fragmentary sectional view taken as suggested by line 5-5 of FIG. 2;

FIG. 6 is a disassembled perspective view of the latch mechanism housing portion of the device;

FIG. 7 is a fragmentary front elevational view of a vertically standing cabinet having a horizontally swinging door controlled by a latch mechanism of the present invention; and

FIG. 8 is an enlarged scale fragmentary sectional view taken as indicated by line 88 of FIG. 7.

Detailed description As shown by way of example at FIG. 1 in the drawing herewith, the invention is adapted to be applied to a cabinet structure including a front wall 10; a rear wall 12; and a top cover or lid 14; the lid 14 being hingedly mounted by means of a hinged device 15 to arear sill portion 16 of the cabinet structure so that when the cover is down in cabinet-closing position its tip surface is flush with the top surfaces of the cabinet members 10, 16. A spring device as indicated at 18 (FIG. 1) is provided to overcome the weight of the cover 14 and to cause it to rise into cabinet-opening position whenever the strike 20 is released from the latch mechanism which is indicated generally at 22. However, it is to be understood that the latch mechanism of the invention may be employed in connection with a large variety of other forms of cabinet and door-cover structures, as well as in connection with horizontally swinging doors or the like as illustrated at FIGS. 7, 8, herein. Also it is to be understood that the spring-opening effect of the cover or door member may be attained through use of any other suitable form of spring or gravity or other power supply device in lieu of the form of spring device 18 of FIG. 1 or of the form of spring device which is shown in FIG. 8 and which will be more fully described hereinafter.

As illustrated at FIGS. 1-5, the latch mechanism of the present invention includes, in combination, a special form of strike device which is indicated generally at 20 and comprises a base portion 24 adapted to be fastened as by means of screws or the like to the cover member 14 as shown in FIG. 1. The strike blade is indicated at 26 and terminates in a cam-shaped nose portion 28 formed to include a laterally extending jaw portion 29, and at its opposite side it is formed to include a laterally extending heel portion 30.

The latch mechanism 22 includes a housing portion 32 which is in the form of a box shaped sheet metal stamping having flange portions 34-34 at opposite ends thereof for mounting the housing against the inside wall portion of the cabinet structure 10, as: by means of screws or the like as illustrated at 36 herein. As shown in better detail in FIG. 6, the housing member 32 is apertured as indicated at 38 to accommodate passage therethrough of the strike member 20' when the cover member 14 is moving between cabinet-opening and closing positions. Also, the front wall portion of the housing member 32 is die-stamped to project inwardly therefrom a pair of right-angle extending lug portions 39-39 upon which are subsequently slip-fitted a pair of cushion sleeves 4040 formed of any suitable rubber or plastic material or the like, for purposes to be explained hereinafter.

The latch device per se of the present invention comprises a rocker member 44 which is pivotably mounted upon the side wall portion of the housing by means of a pivot device designated 46. The rocker member 44 includes at one end a laterally extending latch arm portion .terminating in a hook end portion 50 which is so disposed as to be directionally aligned with movements of the nose portion 28 of the strike member as the latter moves in accordance with opening and closing of the cover member 14. The hook portion 50 of the rocker member is of rounded external form, so that whenever the nose portion 28 of the strike member 20 comes into bearing relation against the external surface of the latch portion 50 the latter is thereby cammed aside, causing the rocker member 44 to pivot in counter-clockwise direction as viewed in FIGS. 2-4 herewith. A tension spring as indicated at 52 is connected as indicated at 53 to one arm portion of the rocker member 44 and is anchored at its other end as indicated at 54 to the housing member.

The parts are so arranged that when the rocker member 44 is in strike-holding position as shown in FIG. 2, the spring 52 is operating to hold the rocker member in strike holding position. Also, the parts are so arranged that when the rocker member is thus operating in strikeholding position the cover member 14 is disposed so that its upper surface is flush with the top surfaces of the front, side, and back wall portions of the cabinet structure. The relatively movable parts are directionally aligned so that when the cover member 14 is subsequently further depressed beyond the cabinet-closing position referred to, the nose portion 28 of the strike member bears inwardly against an abutment portion 56 of the rocker member 44 which is eccentrically displaced from the axis of the pivotal connection device 46.

Therefore, assuming the mechanism to have been previously shifted to cover-holding position as shown in FIG. 2 herewith, upon subsequent further depression of the cover member as illustrated by FIG. 3, the nose portion 28 of the strike member bears against the abutment portion 56 of the rocker member so as to cam the latter against the action of the spring 52 in counter-clockwise direction and into the attitude illustrated by FIG. 3. In this position of the parts the pull-line of the spring 52 has been carried to the left across the center of the pivot axis of the device 46; and therefore the rocker member 44 is now held in the attitude shown in FIG. 3, whereby the strike member 20 is fully released from its previous engagement with the hook portion 50 of the rocker member. Therefore, the cover member 14 is now released to swing open under the impetus of the spring device as indicated at 18.

It is also an essential feature of the mechanism of the invention that the rocker member 44 carries at its opposite end a flange portion 58 which is shaped to camwise engage with the heel portion 30 of the strike member 20 whenever the latter moves outwardly of the latch mechanism housing as explained hereinabove. As illustrated by FIG. 4, this camming action of the strike member against the flange portion 58 of the rocker member causes it to pivot in clockwise direction so as to free the strike member totally from engagement with the rocker member, while at the same time disposing the latter so that the line of pull of the spring 52 has been shifted back to the right beyond the axis of the pivot device 46. The parts are so shaped that as the heel 30 of the strike earns the fiange portion 58 of the rocker in clockwise direction the hook portion 50 of the rocker comes back against the strike below the level of the jaw 29, whereby the strike is free to escape from the latch. Hence, the rocker member will now be pulled back down into the attitude illustrated at FIG. 2 in preparation for a subsequent reception of the strike member in cover holding position as illustrated at FIG. 2. It will of course be understood that the cushion-stop devices 40-49 are so positioned as to appropriately limit the back and forth rocking movements of the member 44 as explained hereinabove.

Whereas FIGS. 1-3 illustrate the cabinet to be of the flush lid type, the cabinet may be of any other styling, such as for example so that the lid 14 is not recessed relative to the side walls, but extends above or overhangs the side walls when in cabinet-closing position. In any case the latch parts will of course be arranged so as to hold the lid 14 at the desired position relative to the cabinet structure, while permitting it to be slightly depressed for subsequent release and opening of the lid.

FIGS. 7, 8, illustrate application of a modified form of the device of the invention in conjunction with a vertically standing cabinet structure which is indicated generally at 60 and upon which is hingedly connected as indicated at 6262 a horizontally swinging door panel 64. An automatic latch mechanism of the invention is shown as being mounted in connection therewith to comprise a strike member 20 as described hereinabove and a latch mechanism 22 of generally similar construction. However, in the case of FIG. 8 the housing member 32 is illustrated to include a slidably mounted plunger 66 which is resiliently biased by means of a compression spring 68 to extend forwardly of the edge-view profile of the cabinet structure.

Hence, whenever the door member 64 is pressed further inwardly beyond cabinet closing position as explained hereinabove, the plunger 66 will be thereby depressed against the action of the spring 68 as the rocker member 44 of the latch mechanism operates to engage the strike 20 in holding relation. Then, upon subsequent further manual depression of the door panel 64 against the latch mechanism and release of the strike member as explained hereinabove, the spring 68 operates to give the door an outwardly moving impetus. Thus an alternative to the spring device 18 hereinabove referred to is provided as an integral part of the latch mechanism per se.

It is a particular feature of the present invention that as shown herein the rocker member 44 is preferably made of some material possessing the so-called self-lubricating or frictionless characteristic, and it is also preferable to make the rocker of some plastic material having the socalled elastic memory characteristic. Suitable materials for this purpose are known in the trade for example as Delrin, nylon, and the like. The strike member 20 and the pivot member 46 for the rocker 44 may then be made of steel or any other suitable metal, whereby the rocker member may be said to be frictionally compatible relative to its pivot connection and to the strike 20. Hence, when the lower end of the strike bears downwardly in sliding relation against the abutment portion 56 of the rocker as shown in FIG. 3 of the drawing herewith, it slides easily against the rocker abutment and avoids any frictional seizing or galling thereof. Also, the rocker freely pivots on the device 46, whereby it will be appreciated that long-life smooth operation of the mechanism is assured. Furthermore, in the event of any abuse of the mechanism such as by slamming of the lid 14 down into closed position or any other action causing inordinate pounding of the strike against the rocker such as may cause momentary plastic deformation of the abutment portion 56, such distortion of the part will be erased by virtue of the elastic memory characteristic of the material. The abutment portion 56 will be immediately restored to its proper cam shape, and hence no permanent deformation or breakage of the parts is experienced.

Also by way of further example, Delrin possesses frictional characteristics such that the static or starting friction coefficient is virtually the same as the dynamic or running friction coeflicient. Therefore the latch mechanism of the present invention responds smoothly and in uniform manner to any kind of manually applied latch-release force, whether it be a deliberate pressure, or a sharp blow. This superior performance of the mechanism continues indefinitely due to the fact that the pivot 46 needs no lubrication, nor do the relatively moving parts 28, 56 and 30, 58, respectively, as they meet in sliding contact relation. Alternatively, the strike 20 may be formed of Delrin or the like, while the rocker 44 is I formed of steel or some other metal, whereby the frictionless characteristics hereinabove referred to may be attained. Also, it will of course be appreciated that rollers or the like may be carried by the strike and rocker parts at strategic points of the mechanism if it is preferred to provide for roller bearing contacts instead of slide bearing contacts between the parts.

It will be apparent from examination of the drawing herewith that in event of mechanical failure of any of the parts of the latch mechanism, such as for example failure of the spring 52 or breakage of its connections or of the pivot pin 46 or the like, the parts will automatically fall into strike releasing positions and cannot possibly jam the strike against escape from the mechanism. Hence, the cabinet will not become locked in cover-closed position to the annoyance or other disadvantage to the user.

It will of course be understood that whereas only a few forms of the invention have been illustrated and described hereinabove, various changes may be made therein without departing from the spirit of the invention or the scope of the following claims.

What I claim as my invention is:

1. A latch for a movable door or cabinet cover or the like whereby two relatively moving parts are to be releasably latched together, comprising in combination:

a strike adapted to be fixed to one of said relatively moving parts and a latch mechanism adapted to be fixed to the other of said parts whereby upon closing of the door or cabinet cover said strike enters said latch mechanism,

said strike having its blade portion terminating in a cam-shaped nose portion and having a jaw portion and a heel portion extending in opposite directions laterally and rearwardly therefrom,

said latch mechanism comprising a housing pivotally supporting a rocker member therewithin and adapted to be fixed to said other part,

said rocker member terminating at its opposite ends in hook and flange portions respectively, said hook and flange portions being arranged in a facing relationship and adapted to receive said strike blade therebetween and spring means arranged within said housing and adapted to alternately bias said rocker to reside in first and second positions,

the strike and latch parts being so arranged that when said rocker is in said first position and said strike blade is moved into said housing said strike blade may engage at its jaw portion the hook portion of said rocker and cam the latter to pivot against the action of said spring means to permit said strike jaw portion to slide by the hook portion of said rocker member, whereupon said spring means operates automatically to return said rocker to said first positi cTii whereupon said rocker hook portion engages said strike jaw portion and locks said strike against exit from the latch mechanism,

said rocker member having a cam surface portion disposed intermediate said hook and flange portion thereof, said cam surface portion being disposed eccentrically of said rocker member pivotal mounting in said housing and aligned for engagement by the nose portion of said strike when the latter is moved further inwardly of said housing beyond the aforesaid locked position, whereupon said rocker is initially forced to pivot against the action of said spring towards strike jaw releasing position and then under the action of said spring means into said second position thereby freeing said strike from locked connection with said rocker hook portion, said spring means being positionally arranged so as to thereupon hold said rocker in strike released position,

said strike heel and said rocker flange portions being so arranged that when said strike is withdrawn from said latch mechanism said strike heel portion engages said rocker flange portion and cams said rocker back towards said first position while said strike is permitted to escape from the latch mechanism, whereupon said spring means action shifts to pull upon and hold said rocker in said first position, in preparation for the next latching operation.

2. A latch as set forth in claim 1, wherein said housing is in the form of a box-shaped sheet metal stamping having one wall thereof open and including a pair of flanges extending in opposite directions from adjacent said open wall, a wall opposite said open wall, and a wall intermediate said open and opposite walls, said housing being fixed to said other part by fasteners extending through said flanges such that said open wall is closed by said other part, said opposite wall pivotally supporting said rocker and said intermediate wall being apertured to accommodate passage therethrough of said strike blade into said housing.

3. A latch as set forth in claim 2 wherein said housing opposite wall is punched out to define a pair of spaced lug portions extending at right angles thereto and a pair of cushion sleeves slip-titted one over each said lug, said sleeves being adapted to limit the pivoting movements of said rocker between said first and second positions.

4. A latch as set forth in claim 1 wherein said rocker pivot device and said strike are each formed of metallic material and said rocker member is formed of a substantially rigid plastic material possessing elastic memory and self-lubricating properties, whereby any distortion of said cam surface portion due to engagement thereof by said strike nose portion is erased.

References Cited UNITED STATES PATENTS 1,509,780 9/1924 Robertson 292-198 2,538,913 1/1951 Roethel 292280 2,929,648 3/1960 Bobrick 292-99 2,946,614 8/1960 Russell 29234l.11 3,061,346 10/1962 Jorgensen 29217 3,212,803 10/ 1965 Russell et a1. 292-107 DAVID J. WILLIAMOWSKY, Primary Examiner. I. K. BELL, Assistant Examiner.

US. Cl. X.R. 49-379

Images