US2729490A - Flush type toggle latch - Google Patents

Description

Jan. 3, 1956 A. F. GANDER 2,729,490

FLUSH TYPE TOGGLE LATCH Filed Nov. 20. 1955 Jig 54 50 v 44 WW 53- w I IN VEN TOR.

/ as 20 79 Arnold f Gander BMW 55 1 5 United States Patent FLUSH TYPE TOGGLE LATCH Arnold F. Gander, Berkeley, Calif.

Application November 20, 1953, Serial No. 393,358

6 Claims. (Cl. 292-196) This invention relates to flush type toggle latches of the type adapted to use on doors of airplanes and the like where the provision of smooth external surfaces is desirable, and more particularly my invention relates to a toggle type latch mechanism which, it desired, is adapted to use in a manner such that it is self-locking when the door upon which it is used is swung from the open to the closed position.

in certain respects, the latch disclosed herein is an improvement of those shown in my United States Letters Patent No. 2,479,921, issued August 23, 1949, and No 2,621,952, issued December 16, 1952, each of which is for Flush Type Toggle Latch.

A general object of this invention is to provide va flush type toggle latch which may not only be set in positions in which it is self-retaining in either an open or locking position, but which is also adapted to be set so that it is self-locking when the door upon which it is mounted is swung from an open to a closed position.

My invention has for another and more specific object the provision of a flush type toggle latch in which a latch bolt is supported for swinging movement between locking and retracted positions and is normally biased toward the locking position by a stressed torsion spring and held in its extreme retracted position, against the action of the spring, by the action of the toggle mechanism.

As another object, my invention comprehends the provision of a flush type toggle latch having a latch bolt spring biased to its locking position and which, when in its locking position, presents a surface disposed for engagementwith a jamb surface during closing movement of a door upon which it is mounted, thereby to cam the latch bolt toward its retracted position, so as to allow the door to close, after which the latch bolt is returned by the spring to locking engagement with a coacting keeper.

Another object of this invention is to provide a flush type toggle latch of the type referred to and in which a spring and a toggle mechanism coact to hold the latch bolt in its locking and extreme retracted positions.

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

Referring to the single sheet of drawings:

Fig. 1 is a fragmentary front elevational view showing the exteriors of a door and door jarnb, as well as exteriorly exposedportions of my latch mechanism when the door is in closed position relative to the jamb and when the toggle latch is in its latching position for holding the door closed;

Fig. 2 is a fragmentary rear elevational view corresponding to Fig. 1;

Fig. 3 is a side sectional view wherein the section is taken substantially on a line 3-3 of Fig. 2 and in the direction indicated by arrows;

Fig. 4 is a side sectional view similar to Fig. 3 but 2,729,490 Patented Jan. 3, 1956 "ice a line 6-6 of Fig. 2 and in the direction indicated by arrows;

Fig. 7 is an end sectional view of the latch mechanism wherein the section is taken substantially on a line 7--7 of Fig. 2 and in the direction of the arrows; and

Figs. 8 and 9 are respectively end and side elevational views showing a spring utilized in the disclosed embodiment of my toggle latch, which views depict the normal positions of portions of the spring structure before it is installed in the assembly of my disclosed toggle latch.

The exemplary embodiment of my invention which is depicted in the accompanying drawings for illustrative purposes is shown in an adaptation to a door and wall structure such as that utilized in airplanes and the like. Although the disclosed latch mechanism may well be adapted mother uses, the illustrated use is considered typical, and it may be readily understood from the following description'that the disclosed latch provides for quick operation of the door, affords seals for moisture and ice, and presents accessible parts for manual operation of the mechanism without having projecting parts on the outer surface which would disrupt the otherwise smooth and streamlined exterior of the door and the wall. The latch structure which is herein disclosed may also be set to the latching position before the door is closed, so that when the door is moved to its closed position, the latch will not interfere with the closing of the door and will move to its latching position to hold the door shut.

Having more particular reference to the structural details of my flush type toggle latch, as depicted in the accompanying drawings, it has a base 10 which is preferably made of sheet metal and has integral and opposed side flanges 12 and 13 extending along the sides of a substantially flat mounting portion 14. At its opposite ends, the mounting portion 14 has suitably spaced openings therein for the accommodation of fastening means, such as rivets 15, by which the base is secured to a supporting structure, such as the inner surface of a door 16. In an installation of the usual type, the base 10 is mounted near a swinging edge 17 of the door 16, which door fits into and provides a closure for a door opening 18 in a wall 19, with the door margin engaging a door jamb 20 when the door is closed. A latch actuator 22, which is preferably made of sheet metal, hasan elongated mid-portion 23 and flanges 24 and 25 extending in opposed relationship along the opposite sides of the mid-portion 23; the exterior width of the flanges of the actuator 22 being such that the actuator tits between the flanges 12 and 13 of the base. The actuator 22 is mounted for limited swinging movement relative to the base by means such as a cross pin 26 which extends through aligned openings in the midportions of the side flanges 12 and 13 of the base and the side flanges 24 and 25 of the latch actuator.

' Near the opposite ends of the actuator 22, and on opposite sides of the cross pin 26 which provides a fixed axis for the swinging movement of the actuator relative to the base, manually engageable latch actuating elements 27 and 28 are secured to the latch actuator. The latch actuating element 27 has a stem portion 29 and a head portion 30 and extends through an opening 32 at one end of the base 10 and an aligned and substantially concentric opening 33 in the door 16. A sealing washer 34 of a re 3m silient material, suchas rubber, is -secured-to-a-recessedportion 35 of the base 10, on the exterior surface of the base, forengagement with the inner surface of .the head portion 30 of the actuating element 27, thereby to provide a seal for the opening 33 in the door when the latch actuator is in one of its operating positions and when the exterior surface of the latch actuating element 27 is in substantially flush relationship to the outer surfaceof the door. As shown in Figs; land 4, the latch actuating element 27 moves outwardly of the door from the position in which its end surface is flush with the door surface to a position in which it projects from an exterior surface of the door; the flush relationship of the actuating element surface to that of the door desirably corresponding-to the latched or holding position of the latch mechanism, so that the smooth exterior is presented when the door is closed, and a manually engageable gripping surface is afforded when the latch is released;

The actuating element 28 T is alignedfor movement through an opening 36 in the baselt) and a substantially concentric opening 37 in the door. A sealing washer 38 of resilient material is secured to and encompasses the latch actuating element 28 for engagement with the inner surface of the base to provide 'a weather seal ,for the openings 36 and 37; Although accessible from ,the,exterior,of the door, the actuating element 28 presentsa relatively flat surface in flush relationship to the exterior offthe door when the dooriis closed and latched, andwis moved inwardly of the door by manual force applied thereto foreffecting release of the latch.

A'latch bolt 39, which is also adapted to fabrication from sheet metal, is of generally U shape and has a ,connecting portion 40 presenting an exterior keeper engaging V surface and opposed side arms 42 and 43., The side arms 42and 43 of the latch bolt, like the side flanges 24 and 25 'of the actuator, fit between extended portions 44 and 45 of the side flanges 12 and 13 of the base and are sup ported at their mid-portions for limitedswinging movements relative to one end of the base by means such as a cross pin 46 which acts as a fixed axis for such swinging movements of the latch bolt. On opposite sides ofthe cross pin 46, the side arms 42 and 43 of the latch bolt each have end portions which extend in obtuse angular relationship to one another, as depicted in Figs. 3' and. 4. In the disclosed structure, a torsion spring 47 having the normal configuration illustrated in Figs. 8 and,9 is mounted on the cross pin 46, so that its coiled portion 48.en-- compasses the cross pin and its opposite ends have project: ing portions 49 and 50 which engage an edge of the leg 43of the latch bolt and extend through an opening in,

the flange 12' of the base after being stressed, so that. the latch bolt is normally biased toward its keeper engagingposition in which it extends beyond the end ofthe base 10, as shownin Fig. 2.

A linkSZ; in the disclosed structure, is substantially U;

shaped and adapted to fabrication from sheet metal It includes a connecting portion 53 and side leg portions 54 and'55, the side leg portions being in opposed relation: ship and spaced apart so that their outer surfaces fit between the inner surfaces of the side flanges 24 and 25 ofthe actuator and also between the inner surfaces ofthe side arms 42and '43'of the latch bolt. At the op-. posite ends of the side legs, the linkis movably connectedto one end of each of the side flanges 24 and,25. of thev actuator by a cross pin 56 and to the end portions of the side arms 42and '43 of the latch bolt opposite the connecting portion 40 of the latch bolt by a cross pin 57.

When the door 16 is closed and the latch is in its ,latchingposition, as shown in Figs. 2 and3, the outerend surface of the connecting portion 40 of the latch bolt en: gages correspondingly curved and angularly disposed end surfaces of keeper elements 58, thereby to hold the ,door, closed.- In this position, the actuator extends in generally parallel relationship alongthe inner surfaceof thebase 10 with the actuating elements 27'and 28 closing the openings-in-the-door.-- Also,- as shown -in-Fig.- 3, the-link-- 52 is angularly disposed relative to both the actuator 22 and the end portions of the latch bolt to which it is connected, whereby the biasing force of the spring 47 against the edge of the arm of the latch bolt acts through the link to urge the sealing washer 38 into contact with the inner surface of the base; 10. Thus, the base 10 and the sealing washer 38 serve as stops for limitingthe movement of the actuator in one direction and thereby hold or retain the latch bolt in a-keeperengaging position.

When the latch which is herein disclosed is .moved to its normal keeper engaging or latching position while the door is open, the latch, bolt'is held ,ll'l substantially the position depicted in Fig. 3, even though the keeper is not engaged, by virtue of the engagement of the sealing washer 33 with the internal surface of the base 10. From this position, closing movement of the door will bring the exposed edges of the latch bolt side arms 42,43 into con tact with the edge of the door jamb 20 with the side arms of the latch bolt angularly disposed relative to the door iamb surface, so that the latch bolt will be moved against the biasing force of the spring 47 by camming action to a position such that the latch bolt will pass the door jamb and the end surfaces of the keeper elements. When the latch bolt is in proper alignment with the keeper elements,

the biasing force of the spring 47 will force it into its holding engagement with the keeper; it being understood that the door. jamb and keeper surfaces do not force the latch bolt far enough toward the fully retracted position to have it lock in that retracted position.

On the other hand, when the latch bolt is moved to its retracted position by manual force applied to the actuating element 28 on the actuator 22, the parts of my latch are so relatively constructed and arranged that, as

shown in Fig. 5, the cross pins 56and 57 which connect the link to the actuator and the latch bolt respectively define. a plane which extends substantially through the fixed axis of the cross pin 26 for the latch actuator 22. In this position, aligned portions of the actuator and link between the cross pins 26, 56 and 57 restrain and hold the latch bolt in its retracted position against the biasing force of the spring 47. Also, in the retracted position of the latch bolt, the stem portion 29 of the latch actuating element 27 engages the sealing washer 34 to provide a stop for the movement of the latch actuator beyond the sired, and when the door upon which the latch mechanism is mounted is moved from the open to the closed position.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departingfrorn the spirit of the invention, and I do not wish to be limitedto the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

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

l. A flush type toggle latch mechanism comprising, in combination, a unitary base structure, a latch actuator hingedly mounted at the mid-portion of the base structure for swinging movement relative to a fixed axis and having actuating knobs thereon for manual operation of the latch mechanism, a latch bolt mounted at one end'of the base structure for swinging movement rclativeito a fixed axis and between latching and retracted positions, said latch bolt being generally U-shaped with side arms each having portions in obtuse angular relationship to one another and a connecting portion adjoining adjacent ends of the side arms and providing a keeper engaging surface, the axis of swinging movement of the latch bolt relative to the base structure being substantially coincident with the junctures of said angularly disposed portions of the side arms so that said portions of each of the side arms extend therefrom in angular relationship, a link having its opposite end portions rotatably connected to adjacent ends of the actuator and the latch bolt side arm portions remote from the said connecting portion thereof by means providing axes which move relative to the axis of swinging movement of the latch bolt when the actuator is moved, a torsion spring having a coil portion encompassing the axis of swinging movement of the latch bolt and end portions extending from the coil portion, which end portions are connected to the base structure and the latch bolt, said torsion spring being normally stressed to exert a force continually biasing the latch bolt toward its latching position,

means providing stops for limiting movements of the actuator at opposite extreme positions of movement relative to the base structure, and the axes of movements of said link being so located relative to the fixed axis of move ment of the actuator and the fixed axis of movement of the latch bolt that when the latch bolt is in either the latching or retracted position, the actuator is held against one of said stop means.

2. A flush type toggle latch mechanism as defined in claim 1, and wherein the axes of movements of the link are in a plane which extends substantially through the axis of swinging movement of the actuator when the latch bolt is in its retracted position, and the axis of swinging movement of the latch bolt is at one side of said plane and spaced therefrom so that the force exerted by said spring on the latch bolt acts through aligned portions of the actuator and link between the said axes thereof to hold the actuator against one of said stop means and the said aligned portions of the link and actuator brace the latch bolt against movement from its retracted position.

3. A flush type toggle latch mechanism as defined in claim 1, and wherein the axes of movements of the link define a plane which extends transversely of a plane defined by the fixed axes of the actuator and latch bolt when the latch bolt is in the latching position, and the biasing force of the spring on the latch bolt acts through the link to urge the actuator against one of the stop means.

4. A flush type toggle latch mechanism as defined in claim 3, and wherein the axis of the means connecting the link to the actuator crosses a plane defined by the fixed axes of the actuator and latch bolt, and the axis of the means connecting the link to the latch bolt is disposed and remains on said one side of the said plane during movements of the latch bolt between the latching and retracted positions.

5. A flush type toggle latch mechanism comprising, in combination, a base structure, a latch actuator mounted at the mid-portion of the base structure for limited swinging movement relative to a fixed axis, a latch bolt mounted at one end of the base structure and near one end of the actuator for swinging movement relative to a fixed axis and between latching and retracted positions, said latch bolt having keeper engaging and connecting portions extending in obtuse angular relationship to one another from the fixed axis about which it moves, a link movably connected to the connecting portion of the latch bolt and to the adjacent end of the actuator by means providing axes which move in relation to both of said fixed axes when the actuator is moved, resilient means having portions engaging the base structure and the latch bolt for biasing the latch bolt in one direction in refer ence to the fixed axis about which it moves, stop means for limiting movement of the actuator relative to the base structure, the axes of movements of the link and the fixed axis of the actuator being substantially in a common plane and the fixed axis of movement of the latch bolt being at the side of said plane such that the resilient means biases the connecting portion of the latch bolt toward the link when the latch bolt is in one of said positions, whereby the biasing force of the resilient means tending to move the latch bolt from said one position is restrained by forces acting longitudinally of the aligned portions of the actuator and link along said plane.

6. A flush type toggle latch mechanism as defined in claim 5, and wherein said actuator and said link are disposed in angular relationship relative to one another when the latch bolt is in the other of said positions, whereby the biasing force of said resilient means acts through the connecting portion of said latch bolt and the link to urge the actuator against said stop means.

References Cited in the file of this patent UNITED STATES PATENTS 2,479,921 Gander Aug. 23, 1949

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