US3047321A - Flush-type toggle latch - Google Patents

Description

July 31, 1962 A. F. GANDER FLUSH-TYPE TOGGLE LATCH 2 Sheetsl-Sheet 1 Filed Aug. 26, 1959 INVENToR. Hander July 31, 1962 A. F. GANDER 3,047,321

FLUSH-TYPE TOGGLE LATCH Filed Aug. 26, 1959 2 Sheets-Sheet 2 INVENToR. Arnold l? @ander www United States Patent O 3,047,321 FLUSH-TYPE TOGGLE LATCH Arnold F. Gander, Berkeley, Calif.

Filed Aug. 26, 1959, Ser. No. 836,255 3 Claims. (Cl. 292-223) This invention relates to toggle type latch mechanisms which are adapted to mounting with an actuating element in substantially flush relationship to a door surface in one of the operating positions of the latch, and more particularly to such latch mechanisms incorporating structural features affording improved safety and more general adaptability in use.

The flush-type toggle latch which is disclosed herein is, in certain respects, somewhat similar to the latch shown in my United States Patent No. 2,621,952, issued December 16, 1952, for Flush-Type Toggle Latch.

One of the objects of this invention is to provide a toggle type latch incorporating spring means for biasing operating parts of the latch to positions to which they were last operated, and wherein said spring means has a plurality of portions which normally aid one another in providing the biasing forces, and various ones of which portions could break during use vvithou-t defeating the operability of the latch, thereby affording a safety factor during use.

As another object, my invention has within its purview the provision of a toggle type latch having a single actuating element which is rocked longitudinally in a unitary opening in a door panel or the like as a result of manual forces applied at one or the other end thereof for effecting actuation `of the latch.

It is another object of this invention :to provide a toggle type latch mechanism having an adjustable gripping element on the keeper which adapts the latch to use with door jambs of various thicknesses.

Other objects and advantages lof fthe invention will be apparent from the lfollowing description and the accompanying drawings in which similar characters of reference indicate similar parts throughout the several views.

FIG. l is a front elevational view of a flush-type toggle latch adapted to use on airplane doors and the like which latch embodies a preferred form of my invention, and in which view a door upon which the latch is mounted is depicted fragmentarily in dot and dash lines;

FIG. 2 is a rear elevational view of the latch shown in FIG. 1, with the door and an associated jamb illustrated fragmentarily;

FIG. 3 is a side sectional view wherein the section is taken substantially as indicated by a line 3 3 and accompanying arrows in FIG. 2, the latch mechanism being shovm in its holding position;

FIG. 4 is a side elevational view of the ldisclosed flushtype toggle latch, wherein the latch mechanism is shown in its retracted position and the door and jamb are illustrated fragmentarily in dot and dash lines;

FIGS. 5 and 6 are respectively side elevational and top plan views of a resilient spring element of a preferred form which is adapted to use in the mechanism of the flush-type toggle latch shown in FIGS. 1 to 4 inclusive, the parts of the spring being illustrated in their normal or unwound positions;

FIG. 7 is a view similar to FIG. 3 showing a flushtype toggle latch mechanism in which some of the parts are of modified structure;

FIG. 8 is a side elevational view similar to FIG. 4, but depicting the modified structure of FIG. 7 in its released position;

FIGS. 9 and l0 are respectively side elevational and top plan views Vof a type of spring different than that shown in FIGS. 5 and 6 which is used in the latch mechanism of 3,047,32l Fatented July 3l, 1962 2 FIGS. 7 and 8, the parts of the spring being illustrated in their normal or unwound positions;

FIG. 11 is a side elevational view of the spring of FIGS. 9 and 10 with the parts thereof in the positions assumed when the latch is in the holding position, as shown in FIG. 7, and wherein other positions of the spring parts corresponding 'to different positions of the latch mechanism are shown in dot and dash lines; and

FIGS. 12 and 13 are fragmentary side elevational views similar to FIG. l1 but providing exemplary illustrations of positions of parts of the spring which would exist if different portions of the spring would break.

Although the illustrated flush-type toggle latch is not limited to use on airplane doors, it is shown in forms which are adapted to such use. When mounted as shown, the unitary actuator for the latch is exposed on an exterior surface `of a door, and when disposed for holding the door in a closed position, the actuator is substantially flush with .the door surface and is provided with a gasket which serves as an air and weatherproof seal. In use, the illustrated latch is biased to the position to which it is last operated by manual movement `of the latch actuator and incorporates a biasing spring which affords a safety factor by having parts which function to maintain the latch in its holding position, even if some portion of the spring breaks as a result of fatigue or for any other reasons. The illustrated latch structure further incorporates an adjustable element which is adapted to accommodate jambs of various thicknesses and to insure that the door is held tightly closed.

Having reference ,to the drawings, and particularly FIGS. l to 6 thereof, wherein an exemplary embodiment of the invention is shown for illustrative purposes, my flush-type toggle latch 15 has 4a base plate 16 presenting a substantially flat mounting surface 17 and having holes 13 therein at spaced positions for the accommodation of fastening means, such as rivets 19, by which the base plate is secured to the surface of -a structure, such as a door, upon which the toggle latch is to he mounted. At the midportion of one end of the base plate 16, -a recess 20 is cut therein to provide metal on opposite sides of the recess for the integral formation of lugs 22 which project in substantially right angular relationship from the rear surface of the base plate. The lugs 22 `are in spaced and opposed relationship to one another.

At the mid-portion of the end of the base plate opposite the recess 20, a slot 23 extends through the `base plate and has integral lugs 24 formed on opposite sides thereof adjacent the end of the base plate and in spaced and opposed relationship to one another. The lugs 24, like the lugs 2-2, project in substantially right angular relationship from the rear surface of the base plate and are formed With reference 'to a longitudinal center line which coincides with that of the lugs 22, so that the parts of lugs at the opposite ends of the base plate are in aligned relationship.

A latch actuator Z5 includes a channel member 26 having side portions 27 which `fi-t movably between the lugs 24 on the base plate and a web portion 28 to which a unit-ary actuating plate 29 is secured by fastening means, such as'rivets 30. A cross pin 32 extends through aligned openings in the lugs 24 and in the longidutinal mid-portions of the side flanges 27 of the channel member 26 to support the latch actuator for swinging movements around the adjacent end of `the base plate 16. In the disclosed structure, the mounting of the latch actuator 25 relative to the base plate 16 provides space lbetween the surfaces of the base plate -and actuating plate for a gasket 33 of a resilient material, such as rubber, which gasket covers the back surface of the actuating plate, `as shown in FIG. 3, and serves as a weatherproof seal between the actuating plate and the surface of the base plate `adjacent the slot 23. An additional resilient gasket 34 is secured to the back surface of the gasket 33 adjacent the channel member 26 at the end of the actuating plate which extends beyond the base plate I6. This gasket 34 extends beyond the end and sides of the actuating plate 23 to provide an exposed marginal portion 35 which is adapted to engage the surface of a structure, such as a door 36, as shown in FIGS. 2, 3 and 4. In use, the actuating plate 29 tits into a substantially conforming opening 37 in the door 36 when the surface 17 of the base plate is mounted against the rear or inner surface of the door.

Particularly when used on airplane doors, the gasket 33 and actuating plate 29 have thicknesses which conform substantially to the thickness of the door 36, so that when mounted as described, the exposed outer surface of the actuating plate is substantially ilush with the surface of the door. With this arrangement, also, the gaskets 33 and 34 provide a weather seal around the actuating plate. In the form disclosed, the actuating plate is of substantially uniform width at its longitudinal midportion `and is rounded at its opposite ends. Being hinged for swinging movement at its longitudinal mid-portion by the cross pin 32 around the end of the base plate 16, the latch actuator overlaps a substantial portion of the base plate upon which it is mounted. It requires only a single opening in the door Vaffording adequate room for operation without danger of having an operator get a finger caught in a small door opening; the direction of operation or movement of the latch actuator being dependent upon the end of the actuating plate to which manual pressure is applied.

A latch bolt 38 has side flange portions 39 adjoined by web portion 4Q and which fit movably between the lugs 2.2 at the end of the base plate opposite the latch actuator 25. A cross pin 42 extends through aligned openings in the lugs 22 and side flange portions 39 to support the latch bolt 38 for swinging movement between positions including one in which the latch bolt extends beyond the base plate, as shown in FIGS. l, 2 and 3, `and one in which it is withdrawn behind the base plate, as shown in FIG. 4. The side flange portions 39 of the latch fbolt are cut away at the end remote from the cross pin 42 to provide space for a jamb engaging element 43 which includes a head portion 44 and a threaded stem portion 45. The stern portion 45 is threaded into the web portion 40 of the latch bolt at a position spaced from the cross pin 42, so that its position is adjustable relative to the web portion 40. A lock nut 46 is provided for securing the jamb engaging element 43 in a fixed position relative to the web portion 40. In the operation of the latch the end surface of the head portion 44 of the jamb engaging element engages the surface of a jamb strip 47, as shown in FIGS. 2 and 3, when the latch bolt is in its holding position. When retracted, the end of the head portion 44 of the jamb engaging element is withdrawn to a position behind the base plate 16, as shown in FIG. 4, so that the latch bolt will pass through the door opening.

The latch actuator 25 is movably and operatively connected to the latch bolt 38 by a channel-type link 4S having side flange portions 49 and a web portion 50. The side flange portions 49 of the link 4S movably tit between the side flange portions Si) of the channel member 26 of the latch actuator and between the side flange portions 39 of the latch bolt 38. At one end, a cross pin 52 extends through aligned openings in the side flange portions 27 on the latch actuator and the side flange portions 49 of the link to provide a movable connection therebetween. At the other end of the link 43, a cross pin 53 extends through aligned openings in the side flange portions 39 of the latch bolt and the side flange portions 49 of the link to provide a movable connection between those parts of the latch mechanism.

The axes of the cross pins 32, 42, 52 and 53 which afford movable supports for the latch actuator and latch bolt and movable connections between the link and the latch actuator and latch bolt are substantially parallel to one another. As shown in FIGS. 3 and 4, it may be observed that the tixed axis 32, about which the latch actuator moves, and the movable axes of the cross pins 52 and 53 which connect the latch actuator, link, and latch bolt are disposed at the vertices of a triangle having dilerent shapes in the holding and retracted positions of the latch bolt. It may also be observed that the axes of those cross pins are close to being disposed in a common plane when the latch mechanism is in the holding position depicted in FIG. 3, and pass through a position of alignment in that common plane when the latch is moved from the holding position of FIG. 3 to the retracted position of FIG. 4. Also, the fixed axis of the cross pin 42 about which the latch bolt swings and the axes of the cross pins 52 and 53 which connect the latch actuator, link, and latch bolt are located at the vertices of another triangle which varies in shape as the latch bolt swings between the latch holding and retracted positions.

In the latch holding position shown in FIG. 3, the angle between a plane passing through the axes of the cross pins 42 and 53 and a plane passing through the axes of the cross pins 52 and 53 is an acute angle. With this arrangement of parts and with this disposition of the cross pins 32, 42, 52 and 53, it may be understood that pressure exerted against the latch bolt which would tend to effect movement thereof to its retracted position for opening the door will urge the latch actuator against the base plate and will thus resist forces tending to open the door when the latch bolt is in the holding position. However, swinging movement of the latch actuator toward a position in which the latch bolt is retracted will move the axis of the cross pin 52 through a plane connecting the axes of the cross pins 32 and 53, and when that plane is passed by the axis of the cross pin 52, any force applied to the latch bolt tending to move it to the retracted position will effect continuance of the movement of the latch actuator and latch bolt toward the retracted position shown in FIG. 4. It may thus be understood that when the latch is in its holding position, any force, such as that of a spring, which maintains the cross pins 32, 52 and 53 in their normal positions with the latch bolt in the holding position shown in FIG. 3 will practically insure the retention of the door in its closed position unless the latch mechanism is operated by the application of force to the latch actuator.

For insuring the retention of the axes of the cross pins in proper positions for securing the door in its closed position when the latch bolt is in its holding position and for effecting snap action of the latch mechanism in both directions when operated by the latch actuator, as well as for providing a safety lfactor for insuring such operation of the latch mechanism, I have provided a resilient spring 54 which is illustrated in FIGS. 5 and 6 and shown in its operative arrangement in the latch mechanism in FIGS. l to 4 inclusive. The spring 54 has coil portions S5 and 56 in axially spaced and substantially coaxial relationship to one another. At adjacent ends of the coil portions 55 and 56, integral arm portions 57 and 58 respectively extend therefrom in spaced and substantially parallel relationship to one another and are integrally adjoined at the ends remote from the coil portions by a connecting portion 59. At the other ends of each of the coil portions 55 and 56, integral arm portions 60 and 62 extend therefrom in substantially parallel and spaced relationship to one another. In its application to the described latch mechanism, the coil portions 55 and 56 encompass the cross pin 53 which connects the link 43 to the latch bolt 38. The arm portions 60 and 62 have loops 63 and 64 on the ends thereof which engage the cross pin 42 by which the latch bolt is movably connected to the base plate. Also, arms 57 and 58 have hook portions, such as 65 on the ends thereof which engage the cross pin 52 `by which the latch actuator is connected to the link.

In the normal or unwound position of the spring 54,

the arm portions assume angles with reference to the axes of the coil portions which are indicated in FIG. 5 by lines a and b. When the spring 54 is in place on the `cross pins 52, 53 and 42, as `shown -in FIG. 3, it is always under stress and in a position to exert a biasing force against the engaged cross pins. As shown in FIG. 5, the angle between the spring arms Awhen the latch is in its holding position is indicated by the lines a and c, While in the released position, the spring angle is represented by the lines a and d. Being continually under stress, it may be understood that the latch is always biased to the position to which it is last operated by the latch actuator, and Ithat the eiiective direction of action of the biasing force on the moving parts of the latch mechanism transfers between the holding and retracted positions when the axis of the cross pin 52 crosses the plane defined by the axes of the cross pins 32 and 53.

In the modified structure of my flush-type toggle latch which is illustrated in FIGS. 7-13 inclusive, the latch parts, including the base plate 16, the lugs 22 and 2li on the base plate, the latch actuator 25, the latch bolt 3S, the ling 48 and the cross pins 32, d2, 52 and 53 are essentially the same as those described, and those parts are each adapted to function in the manner described. However, in this modified structure, a spring 65, of the type illustrated in FIGS. 9 and 10, is utilized to efect the snap action of the latch mechanism, to provide the biasing forces for holding the latch mechanism in the position to which it is last operated and to provide a safety factor for holding the latch in its holding position in the event of a failure of a part of the spring.

As illustrated in FIGS. 9 and 10, the spring 65 has coil portions 66 and 67 in spaced relationship to one another and integrally connected by an arm portion 68 which adjoins corresponding and substantially aligned ends of the coil portions. At the end of the coil portion 66 opposite the arm portion 6g, an integral arm portion 69 extends from the coil portion in angular relationship to the arm portion 68. Also, at the end of the coil portion 67 opposite the arm portion 68 an integral arm portion 70 extends from that coil portion in angular relationship to the arm portion 68. The parts of the spring are shown in their normal or unsprung positions in FIGS. 9 and 10.

In use on the illustrated latch mechanism, the coil portions 66 and 67 of the spring 65 encompass the cross pins S2 annd 53 at the opposite ends of the link 48. The arm portion 70 has an end loop 72 thereon which engages the cross pin 42 upon which the latch bolt is mounted for swinging movement. The arm portion 69 has a loop 73 on the end thereof remote from the coil portion 66 which engages the coil pin 32 upon which the latch actuator is mounted for rocking movement relative to the end of the base plate 16. When thus engaged with the cross pins, the portions of the spring 65 are continually stressed. That is, as shown in FIG. 1l7 the angles between the spring arms in the normal or unsprung positions of the arms are designated as A and A. When the spring is installed in the latch mechanism and the latch parts are in their released positions, the angles between the arms are designated as B and B. When the latch is in its holding position, the angles C and C represent the displacements of the arm portions of the spring. Also, it may be observed that as the latch mechanism moves through its center position, at which the axis of the cross pin 52 crosses the plane defined by the axes of the cross pins 32 and 53, the angles between the arm portions of the spring are designated as D and D'.

As indicated in FIG. 12, breakage of the spring arm 70 would leave the arm portions 68 and 69 in operative condition to exert biasing force for holding the latch mechanism in its holding position. Likewise, as shown in PIG. 13, breakage of the arm portion 69 of the spring would leave the arm portions 68 and 70 in operative condition to exert biasing force for retaining the latch mechanism in either its holding or released position.

Thus, by reference to the drawings and the description of the structure and operation of the disclosed latch mechanism, it may be observed that I have provided a flush-type toggle latch having a unitary actuator, a latch bolt which is adjustable to accommodate door jambs of various thicknesses and I have utilized in this latch structure springs which afford a factor of safety by maintaining the operativeness of the latch, even though a p0rtion of the spring breaks.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a hush-type toggle latch mechanism, the combination comprising a base member having an open slot at one end which extends to the mid-portion thereof, a latch actuator having a portion mounted in said slot and including an actuating plate with one end of a size for covering said slot and an opposite end portion extending outwardly from the base member, a cross pin providing a fixed axis and supporting the latch actuator at its midportion for rocking movements relative to said one end of the base member between a latching position substantially parallel to the base member and a releasing position in angular relation to the base member, a latch bolt, a second cross pin providing a xed axis and supporting the latch bolt for swinging movements relative to the end of the base opposite said open slot, said latch bolt having a holding position in which it projects beyond the end of the base opposite said open slot and a retracted position in which it is withdrawn from the holding position and extends angularly from the base member, a link having opposite ends movably connected by cross pins to the latch actuator and latch bolt for effecting movements of the latch bolt between said holding and retracted positions in response to said' rocking movements of the latch actuator between said latching and releasing positions by pressure applied to opposite end pox'- tions of said actuating plate, unitary spring means including a plurality of coil portions with integral arm portions on opposite ends of each of the coil portions, said arm portions on each of the coil portions having normal unsprung positions in predetermined angular relationship to one another, each coil portion encompassing one of said cross pins and the arm portions thereon having engagement with cross pins other than said one and exerting forces thereon in the same directions in all positions of the latch mechanism.

2. In a Hush-type toggle latch mechanism as defined in claim 1, the coil portions of said spring means having substantially parallel axes spaced from one another and two of said ends thereof being integrally adjoined through one of said arm portions, and the arm portions ron the other ends of the coil portions normally extend- References Cited in the file of this patent UNITED STATES PATENTS 1,482,049 Swanson Jan. 29, 1924 2,092,395 Hill Sept. 7, 1937 2,479,921 Gander Aug. 23, 1949 2,621,952 Gander Dec. 16, 1952 2,639,178 Hogan May 19, 1953 2,921,810 Smith Ian. 19, 1960

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