US3516700A

US3516700A - Latch device

Info

Publication number: US3516700A
Application number: US702665A
Authority: US
Inventors: Nils O Myklestad
Original assignee: NILS O MYKLESTAD
Current assignee: NILS O MYKLESTAD
Priority date: 1968-02-02
Filing date: 1968-02-02
Publication date: 1970-06-23
Anticipated expiration: 1987-06-23

Description

June 23, 1970 N. o. MYKLESTAD 3,515,700

LATCH DEVICE Filed Feb. 2, 1968 3 Sheets-Sheet 1 Fig. 2 A

mvmon Nils O. Myklesrad BY W ATTORNEY) June 23, 1970 N. o. MYKLESTAD 3,515,700

LATCH DEVICE Filed Feb. 2, 1968 3 SheetsSheet 2 INVENTOR Nils O. Myklestad W X4 3 ATTORNEY June 23, 1970 a N. o. MYKLESTAD 3,516,700

LATCH nnvxcz:

Filed Feb. 2, 1968 3 Sheets-Sheet 5 mvmon Nils O. Myklesrcld Fig.7. BY i g:

United States Patent Office 3,516,700 LATCH DEVICE Nils O. Myklestad, 1022 S. Cooper, Apt. 243, Arlington, Tex. 76010 Filed Feb. 2, 1968, Ser. No. 702,665 Int. Cl. Eb 15/02; E05c 3/16, 9/10 US. Cl. 292-49 14 Claims ABSTRACT OF THE DISCLOSURE A latch for releasably connecting separable parts and having a pair of spaced pivoted latch arms supported by one part for a releasable engagement with a locking plate mounted on another part. The latch arms are supported on spaced rotatable shafts actuated by a cam pivotally mounted on a rotatable operating shaft etxending between the latch arm shafts and engageable with a crank on each of the latch arm shafts for rotating the shafts to pivot the latch arms toward each other to release position. The latch arm shafts are biased apart to a locking position by a spring connected between the levers. The latch arms lock over a substantial distance on arcuate locking surfaces in the locking plate permitting substantial tolerance for misalignment between the interlocked parts.

This invention relates to holding or securing devices and more particularly relates to a latch for releasably securing together separable parts.

It is one object of the invention to provide a new and improved latch for releasably connecting adjacent parts such as doors and door frames of structures such as buildings, vehicles, and the like.

It is another object of the invention to provide a latch of the character described wherein as the latch arms are introduced into the keeper they are frictionally held against withdrawal by engagement with arcuate locking surfaces extending a substantial distance relative to the keeper while moving freely into the keeper whereby the part supporting the latch arms moves freely to a closed position relative to the part supporting the keeper but is not withdrawable relative thereto without swinging of the latch arms to disengage them from the keeper.

It is another object of the invention to provide a latch of the character described wherein the latch arms are mounted on shafts each having a crank engageable by cam secured on a shaft between the latch arm shafts for pivoting the latch arms toward each other to a released position and including a spring between the latch arm cranks whereby the arms are biased outwardly away from each other toward latching position.

It is another object of the invention to provide a latch of the character described which is quieter in operation than standard latches due to the pivotal action of the pivoted latch arms and the arcuate surfaces of the latch arms and the keeper.

It is a further object of the invention to provide a latch of the character described which has sufficient tolerance in the latched relationship between its latch arms and the arcuate holding surfaces of the keeper to accommodate substantial warping or misalignment between the releasably latched parts.

It is a further object of the invention to provide a latch of the character described which is responsive to only slight closing pressure thereby minimizing noise and any necessity for slamming the parts together.

It is a further object of the invention to provide a latch of the chraacter described having a keeper provided with friction surface portions for absorbing shock forces during the latching and releasing of the latch to minimize latch damage.

3,516,700 Patented June 23, 1970 It is a further object of the invention to provide a latch of the character described which is particularly adaptable to vehicle use, such as on automobiles, wherein the device permits the door to jar from an initial closed position to a fully closed position while not being susceptible to jarring open; so that, if the door is initially only partially closed, vibration of the vehicle over a short distance effects tight closing of the door, thereby providing a substantially self-closing latch.

It is a still further object of the invention to provide a latch of the character described wherein the shape of the latch arms and keeper minimize the probability of picking or unauthorized entry since both of the latch arms must be pivoted inwardly and the end portions of the arms are substantially inaccessible for engagement by a release device for forcing the dogs to an unlocked position.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIG. 1 is a vertical edge view of a door supporting a latch arm assembly of a latch embodying the invention, showing the latch arms pivoted apart to latching or holding positions;

FIG. 1A is a view of the apparatus of FIG. 1 showing the latch arms pivoted inwardly to positions at which they may be released, withdrawn from and also introduced into the keeper;

FIG. 2 is a vertical view in section taken along the line 22 of FIG. 1 showing the latch arm assembly with latch arms pivoted apart to latching positions;

FIG. 2A is a vertical sectional'view of the apparatus shown in FIG. 2 taken on the line 2A2A of FIG. 1A and illustrating the latch arms pivoted inwardly to their release positions as in FIG. 1A;

FIG. 3 is a vertical view in section taken along the line 3-3 of FIG. 2 showing portions of the cranks on the latch arm shafts;

FIG. 4 is a horizontal view in section taken along the line 4-4 of FIG. 1 and showing additionally a fragmentary section of a door frame and a keeper in which the latch arms are engageable;

FIG. 5 is a fragmentary vertical view in elevation of a door frame edge showing a keeper for receiving the latch arms;

FIG. 6 is a fragmentary vertical view in elevation of the door frame edge and the keeper taken at a right angle to and from the right side of the view of FIG. 5;

FIG. 7 is an enlarged schematic view of one of the latch arms and a fragment of a holding surface of the keeper, showing the latch arm entering the keeper and the latching position of the arm from an initial to a fully latched position;

FIG. 8 is a perspective view of the latch arm and actuating shafts showing the relationship of the cam and crank mechanisms for operating the latch arms; and

FIG. 9 is a fragmentary vertical view in elevation similar to FIG. 6 showing a modified form of keeper for receiving the latch arm.

Referring to the drawings, a latch 10 embodying the invention includes a latch arm assembly 11 supported in a door 12 and a keeper 13 secured along the edge of a door frame 14. The latch arm assembly includes a pair of pivoted

latch arms

15 and 20 which are received in the keeper for releasably latching the door relative to the door frame. The swingable free ends of the latch arms are resiliently biased outwardly apart to their latched or holding positions, FIG. 1, by a spring 21, and the ends of the arms are pivoted toward each other by a cam 22 supported on a shaft 22a turned by door knobs 23 and 24. When pivoted by the cam toward each other to their retracted positions, FIG. 1A, the latch arms are movable into and out of the keeper. At the expanded or pivoted apart positions of the latch arms in the keeper friction between the free end tip portions of the latch arms and the arcuate surfaces of end portions 25a and 25b of an arcuate friction band 25 of the keeper holds the latch arms in releasable latch relationship in the keeper. The latch arms are cammed inwardly by the keeper and freely move into the keeper as the door is pushed toward the door frame. In the keeper the latch arms tend to more tightly engage the arcuate surfaces of the keeper friction band responsive to any force tending to open the door at any position of the arms between their initial holding positions and fully closed positions. The arms are releasable from the keeper only by rotation of the door knob to simultaneously pivot the latch arms toward each other from their holding or latching positions.

The latch arms and are pivotally supported along the edge 12a of the door 12 on the outward ends of shafts and 31, respectively, which are rotatably disposed through parallel spaced

sleeves

32 and 33, respectively, secured in bores 32a and 33a in the door and connected along outward end portions to the plate 34. The plate 34 is secured by screws 35 in counter-sunk or recessed relationship along the door edge. A central stop plate is secured on the plate 34 between the latch arms to limit their pivotal movement both toward and away from each other. The plate 40 has lower and upper arcuate recesses defined by surfaces 41 and 42 which, respectively, receive the semi-circular end portions 15a and 20a of the

latch arms

15 and 20. The arcuate surface 41 is engaged by the edge surface 15b to limit the inward pivotal movement of the lower arm 15, while, similarly, pivotal movement of the upper latch arm 20 is limited by engagement of the inward side edge 20b of the arm with the arcuate surface 42. A stop shoulder 150 on the arm 15 engages a shoulder 40a on the plate 40 limiting the outward pivotal movement of the arm 15. Similarly, a stop shoulder 20c on the arm 20 engages an upper shoulder 4% on the plate 40 limiting the outward pivotal movement of the arm.

The latch arm shaft 30 is held in the sleeve 32 by a locking sleeve or ring 43 secured on the shaft 30 by a pin 44 inward of the sleeve 32 within the bore 32a. The shaft 31 is held in the sleeve 33 by a locking sleeve or ring 45 secured by a pin 46 on the shaft 31 inward of the sleeve 33 in the bore 33a. The inward end portions of the

shafts

30 and 31 extend into a tubular housing 50 disposed in a horizontal opening 51 through the door 12.

.The housing '50 extends from one side of the door partially through the door in the opening 51 and is secured in the door by a plate 52 disposed along the other side of the door over the opening and connected with the housing by screws 53. An external annular flange 54 on the housing 50 engages the surface of the door limiting the extent to which the housing extends into the opening 51.

An operator crank secured on the shaft 30 is engageable by either end portion of the cam 22 for pivoting the latch arm 15 between its outward holding and inward release positions. The crank 60 comprises a pair of

brackets

61 and 62 secured in parallel spaced relationship on a shaft 30a which is pivotally supported in the housing aligned longitudinally with and connected along a reduced end portion 30b into the shaft 30 by a pin 300, FIG. 2. An operator rod 63 extends between the free ends of the brackets spaced from and substantially parallel to the shaft 30a and engageable by the lower arcuate surface 22b of the cam 22. It will be evident in FIGS. 2 and 2A that irrespective of the direction of rotation of the cam 22 on the shaft 22a by either of the door knobs 23 or 24, one end portion or the other of the cam engages the operator rod 63 forcing the crank 60 down- 4 wardly, rotating the connected shafts 30a and 30 in a counterclockwise direction as seen in FIG. 1 and pivoting the latch arm 15 upwardly toward the plate 40 from the position of FIG. 1 toward the position of FIG. 1A. The lower end of the spring 21 is connected by a pin 64 to the bracket 61 biasing the crank 60 upwardly and thereby biasing the latch arm shaft 30 and the latch arm 15 in a clockwise downwardly direction away from the plate 40 toward the position of FIG. 1.

An upper operator crank for pivoting the upper latch arm 20 includes a shaft 31a pivotally supported at its opposite ends in the housing 50 and having a reduced end portion 31b received in and pinned to the inward end of the latch arm shaft 31 by a pin 310. The crank 70 further includes spaced

brackets

72 and 73 secured on the shaft 31a connected by an operator rod 74 extending parallel to and spaced from the shaft 31a and engageable by the upper surface 220 of the cam 22. The upper end of the biasing spring 21 is secured to the bracket 73 by a pin 75 so that the spring 21 biases the crank 70 downwardly tending to rotate the shaft 31a and the shaft 31 in a counterclockwise direction thereby biasing the latch arm 20 upwardly away from the plate 40 toward its holding position. An upper arcuate surface portion 220 along one end portion or the other of the cam engages the operator rod 74 when the cam is rotated in either direction, lifting the crank 70 and rotating the

connected shafts

31a and 31 in a clockwise direction, as viewed in FIG. 1, for pivoting the latch arm 20 downwardly toward the plate 40 to its release position.

The cam 22 is symmetrical, spaced substantially midway between the

cranks

60 and 70, and is sized such that when rotated in either direction the arcuate upper and lower cam surfaces 220 and 22b, respectively, engage the upper and lower cranks substantially simul taneously forcing the cranks apart thereby pivoting the

latch arms

15 and 20 toward each other at the same time for releasing the latch arms from the keeper. There is more tolerance between the cranks and the cam so that even When the latch arms are pivoted apart to their extreme latching positions as shown in FIG. 1, the operator rods of the cranks are not actually engaged with the cam surfaces. When the latch arms are not within the keeper, as when the door is open, the spring 21 may pull the

cranks

60 and 70 together pivoting the latch arms farther outwardly until the stop shoulders on the latch arms engage the plate 40.

It will be clear that the

latch arms

15 and 20 are each pivoted inwardly against the force of the spring 21, independently of the cam, by force applied to the latch arms outward of their axis of rotation such as the camming forces applied by the keeper surfaces to the latch arms as the arms are inserted into the keeper.

The latch arms are constantly biased outwardly by the spring 21 and yet are free to pivot individually inwardly and outwardly between their release and fully latched positions so long as the cam 22 is substantially horizontal. It is important that the latch arms be free to pivot either simultaneously or independently and be biased constantly outwardly to provide constant friction between the latch arm ends and the arcuate keeper friction surfaces for the self closing feature of the latch and to accommodate the latch to irregularities in the keeper surface and misalignments between the door and the door frame so that at all times when in latched relationship both the upper and the lower latch arms are fully engaged in the proper relationship in the keeper, as will be explained. The only time the latch arms are not free to pivot inwardly and outwardly is when they are held fully or partially inwardly by the cam 22 as when they are held inwardly for release from the keeper by turning one of the door knobs.

The keeper 13 (see FIGS. 5 and 6) includes a substantially rigid frame mounted on a vertical back plate 82 secured by screws 83 in a vertical slot 84 formed in the edge of the door frame. The friction band 25 is disposed within the frame 80 and held in place along its central portion by a locking plate or clip 91 secured by a screw 92 extending through the plate 82 into the door frame.

The frame 80 has identical upper and lower slots or recessec 85 and 85a and identical upper and lower arcuate lips 86 an 86a, defining an entrance or mouth 87 of the keeper opening into a latch arm recess 88 defined by the inner surface of the friction band and the adjoining frame surfaces along the upper and

lower lips

86 and 86a. The friction band 25 is disposed within the frame conforming to its internal shape and extending around the interior of the frame substantially from the upper lip 86 to the lower lip 86a. A cleat 91 secured by a screw 92 in the keeper back plate 82 holds the friction band in place along a central portion thereof. The friction band is preferably formed of a resilient spring-like material such as sheet brass and shaped so that when inserted in the frame 80 its upper and lower end portions 25a and 25b are biased outwardly apart and tend to remain in place within the frame along the recesses 85 and 85a, respectively, while flexing sufficiently to accommodate outward movement of the latch arm tips, particularly when the door is slammed and bounces back as explained hereinafter. The end portion 25:: of the friction band is disposed along a back-up block 93 supported against a shock absorbing block 94 formed of a resilient material such as rubber. The

blocks

93 and 94 are positioned in the upper recess 85 of the keeper frame 80. The block 93 is held in the frame by

end extensions

93a and 93b which engage spaced shoulders provided within the frame recess to hold the block against a slightly compressed block 94 in shock absorbing relation behind the end portion of the friction band. The rubber block 94 is partially received within a re cess 93c of the block 93 with ample space being provided between the block 93 and the frame to permit compression of the block 94 responsive to a force ap plied along the surface of the end position of the friction band. Similarly, an identical back-up block 93 and a shock absorbing block 94 are disposed in the same relationship in the lower frame recess 85a resiliently for supporting the lower friction band end portion 25b. A relatively thin cover plate 95 is secured along the edge of the door frame by screws 100 overlying the frame 80 to protect and aid in holding the friction band and the upper and

lower blocks

93 and 94 in place. The plate has a recess, not shown, substantially conforming to the shape and size of the latch arm recess 88 to permit entry and withdrawal of the latch arms.

The coaction between the latch arms and the end portions of the friction band and the

keeper frame lips

86 and 86a is illustrated diagrammatically in FIG. 7 and explained hereinafter in connection with the operation of the latch.

The operation of the latch will be considered in terms of the movement of the door 12 from an unlatched position relative to the door frame 14 to a latched or locked position and the subsequent release or unlatch ing of the door. When the door is open or not latched, the latch arms and are biased apart to substantially the positions illustrated in FIGS. 1, 2 and 8, by the spring 21 acting through the

levers

60 and 70. The latch arms generally are biased pivotally apart from each other by the force of the spring to positions at which the stop shoulders 20c and 150 on the

latch arms

20 and 15, respectively, engage the shoulder surfaces 40b and 40a, respectively, the central plate 40. Preferably the stop shoulders on the latch arms engage the plate before engagement of the operator bars of the

cranks

60 and 70 with the cam 22 to minimize possible damage to the cranks or shearing of the pins connecting the cranks with the latch arm shafts in instances where the door is slammed and bounces back. With the stop shoulders on the latch arms engaging the central plate while the

cranks

60 and 70 are still spaced from the cam, some tolerance is provided between the cam and the cranks so that the door knobs are rotatable slightly in either direction without rotating the latch arms.

The door 12 is moved from its open position toward the door frame with the latch arms passing through the entrance 87 the outward edge surfaces 15d and 20d of the latch arms engage the

lips

86a and 86, respectively, of the keeper frame. The latch arms are cammed inwardly by the lips until the latch arm 20 passes the lip 86 and, simultaneously, the latch arm 15 passes the lip 86a. The door continues to move toward the door frame and the latch arms pass into the recess 88 of the keeper. As see nin FIG. 1, the inward camming of the latch arms rotates the shaft 31 connected with the arm 20 in a clockwise direction, while similarly the camming of the lower latch arm 15 in a counterclockwise direction rotates the shaft connected with the latch arm counterclockwise so that the upper and

lower cranks

70 and 60, connected with the latch arms move apart on opposite sides of and away from the cam 22 against the force of the spring 21. As previously discussed, the latch arms are free to be cammed toward each other and the central plate independently of the cam 22.

The passage of the latch arms into the keeper recess is illustrated by the position A of the upper latch arm shown diagrammatically in FIG. 7. The arcuate shapes of the latch arm tips and the keeper lips allow the latch arms to slide past the lips with a minimum of noise and generally essentially none of the normal latch clicking sound. As soon as each of the latch arms passes its keeper frame lip, the biasing force of the spring 21 acting through the cranks on the latch arm shafts pivot the latch arms apart within the keeper recess to positions as represented by the position B in FIG. 7 at which the upper and lower latch arms move respectively above and below the

lips

86 and 86a. The latch arms cannot be withdrawn from the keeper without pivoting the latch arms back toward each other sufficiently to clear the lip portions of the frame. At the position B of the upper latch arm a line xx drawn from the axis of rotation of the latch arm to the point of contact of the arm with the keeper surface lies below a normal line x-y drawn normal to the arcuate friction surface 25a at the point of contact to the latch arm with the keeper so that a force tending to withdraw the latch arm from the keeper would cause the upper latch arm to be forced upwardly along the surface 25a.

Similarly, the lower latch arm would be forced downwardly along the lower friction surface 25b thereby preventing or precluding the withdrawal of the latch arm from the locking plate recess except by pivoting the arms inwardly with the cam 22 to clear the lips. Thus, the door is effectively latched as soon as the latch arms pass into the keeper recess and are pivoted outwardly against their respective friction surfaces to the points where the axis of each arm lies within the lines normal to the friction surface at the location of contact of the point of the latch arms with the friction surface. After the latch arms pass into the keeper recess just about the position B along the friction surfaces, the latch arms cannot slide out of the recess along the friction surfaces and thus may be removed only by positive pivotal movement of the latch arms toward each other, as by the cam 22. As the door continues movement into the door frame and the latch arms move farther into the keeper recess, the outward biasing force on them holds their tip portions in contact with the friction surfaces of the keeper. The latch arms move to the positions relative along the friction surfaces illustrated by the positions C and D in 'FIG. 7. At these positions the angle between the line XX along each latch arm and the normal line XY to the friction surface is less than the friction angle so that the friction between the end of each latch arm and the friction surface holds each latch arm against movement toward the mouth of 7 the keeper recess and thus holds latch arms in the recess. The position -D is considered to be the position of the latch arm at the fully closed or latched position of the door. Thus, it will be evident that the door is latched over a substantial distance of movement, from the time the latch arms pass inwardly of the lip portions of the keeper frame represented by the position B in FIG. 1 to the fully latched or closed position represented by the position D. From the time that the latch arms pass approximately the position B the door is latched against opening though the latch arms will freely move into the keeper recess until the door is at a fully latched position.

When the latch arms are in the keeper between the positions B and D, the inaccessibility of the free ends of the latch arms and the necessity that both arms be pivoted inwardly at the same time provide maximum protection against picking or unauthorized entry.

If the door is slammed with sufficient force to carry the latch arms slightly past the positions D with resultant boucing back of the door the friction between the friction surfaces of the keeper and the latch arms may pivot the latch arms farther apart until their pivotal movement is stopped by engagement of the stop shoulders c and 150 with the

shoulders

40b and 40a, respectively, of the plate 40. At the same time, the additional outward movement of the tips of the latch arms tends to force the end portions a and 25b of the friction strip 25 outwardly against the back-up blocks 93 with the shock or force being absorbed by the rubber blocks 94 shown in detail in FIG. 6. As the vibrational motion induced in the door due to the slamming subsides, the latch arms return to approximately the position D where the friction between them and the friction surfaces 25a and 25b continues to hold the door at the fully latched position.

The door is released or unlatched by withdrawal or release of the latch arms from the keeper recess 88 by rotating or pivoting the arms toward each other until their free ends will pass outwardly of the mouth 87 between the

lips

86 and 86a of the frame 80. Either of the door knobs 23 or 24 is rotated in either direction so that one end portion of the cam 22 is moved upwardly while the other end portion is moved downwardly between the operator rods '63 and 74 of the cranks on the latch arm shafts. The upper cam surface 220 along the upwardly extending cam end portion engages the operator rod 74 on the upper crank 70, lifting the rod and rotating the

connected shafts

31 and 31a connected between the crank and the latch arm 20, and so pivoting the latch arm downwardly in a clockwise direction as seen in FIG. 1. Simultaneously, the lower cam surface 22b along the downwardly extending cam end portion engages the operator rod 63 on the lower crank '60, rotating the shafts a and 30 in a counterclockwise direction and pivoting the lower latch arm upwardly. The door knob is rotated until the latch arms are pivoted toward each other to the positions shown in FIG. 1A, at which the inner side surface 20b of the upper latch arm engages the arcuate plate surface 42 and the side surface 15b of the lower latch arm engages the arcuate plate recess surface 41. The tips of the latch arms are then sufficiently close together to clear the mouth of the keeper recess so that the door may be freely moved away from the door frame withdrawing the latch arms from the keeper recess. Release of the door knob permits the spring 21 to pull the cranks and toward each other, pivoting the latch arms outwardly and returning them to the positions shown in FIGS. 1 and 2. As the cranks are pulled together by the spring, the operator rod 74 of the upper crank engages the upper cam surface 220 while similarly the rod 63 of the lower crank engages the lower cam surface 221) to rotate the cam 22 back to its neutral or substantially horizontal position. It will be recognized, of course, that the cam is rotatable in either direction, and regardless of the direction of rotation, the end portion moving upwardly acts with the upper crank 70 while the end portion moving downwardly acts with the lower crank 60,

and similarly, when the door knob is released, whichever end portion of the cam is extending upwardly is engaged by the upper crank while the other end portion of the cam extending downwardly is engaged by the lower crank.

The substantial travel distance between the initial latching positions of the latch arms in the keeper and their final latching positions, as already discussed, especially adapts the latch to warped door conditions, misalignments between doors and door frames, and other similar conditions which affect the relative positions of the latch arm assemblies and the keeper. Also, the free movement of the latch arms from their initial latched positions to their final or fully latched positions while at all times remaining securely latched during such movement especially accommodates the latch to use under conditions where the parts held together by the latch are initially only partially closed relative to each other, a condition often occurring with automobile doors. For example, when the latch is used on a door of a vehicle such as an automobile and the door is initially only partially closed, the door does not open but, on the contrary, the movement of the vehicle vibrates the door to its fully closed position, since the door is freely responsive to any forces tending to close it but does not respond to a force attempting to open it so long as the latch arms have at least reached the position B within the keeper. This may be considered as a self-closing feature.

Once a door having a latch 10 is latched, it will not rattle. Since the latch arms are independently operable and may be at slightly different positions of rotation and since each latch arm constantly engages the friction band surface along its free end, any force tending to rattle the door merely moves it to a more securely closed position. Since the latch arms are freely cammed inwardly, slamming is not required in closing the door. The smooth cooperating surfaces of the latch arms and the closure plate minimize noise and substantially eliminate clicking sounds.

While the latch has been described and illustrated primarily in terms of its application to a door of a building, it is to be understood that it may be used to releasably secure together many forms of relatively movable parts. As already discussed, the latch is especially well adapted for use in vehicles such as automobiles, trucks, and the like where safety considerations are paramount, and the latch will cause a door to vibrate to a fully closed rather than an open position.

The latch may accommodate any suitable form of lock which limits the movement of the door knob shaft 22:: sufiiciently to limit rotation of the cam 22 enough to prevent release of the latch arms. Such a lock may include a key actuated release if desired.

It will now be seen that a new and improved latch has been described and illustrated for use in releasably securing relative movable adjacent parts, such as building doors, truck and automobile doors, and the like. It will be further seen that the latch is effectively engaged over a substantial distance between an initial and final latching positions so that misalignment between the parts is readily accommodated and that the latch is freely movable from an initial latching position to a final latching position so that vibratory forces tend to jar the latch to a fully closed rather than to an open position.

It will be further seen that the latch includes pivotally supported spaced latch arms having arcuate surfaces engageable with arcuate friction surfaces in a keeper so that the latch arms move smoothly and quietly into the keeper. It will also be seen that the latch arms are not readily accessible for insertion of a tool from outside of the latch and the latch arms must both be pivoted inwardly toward each other for release, providing maximum protection against picking or unauthorized entry. It will also be seen that the latch arms are movable within the latch plate responsive to only slight closure pressure, further minimizing noise and substantially eliminating any need for slamming the parts together. It will be further seen that the latch is provided with means for absorbing shock forces without latch damage in the event the parts are slammed together.

FIG. 9 illustrates an alternate form of keeper 13A which may be used in the latch where a door is not subjected to substantial shock forces resulting from slamming. The alternate form of keeper is more simple, in design and less expensive to manufacture. The keeper 13A differs from the keeper 13 illustrated in FIG. 6 only by elimination of the shock absorbing features along the end portions of the friction band 25. The keeper 13A has a frame 180 which has the same general internal configuration as the keeper frame 80 and is provided with

arcuate lips

86 and 186 corresponding to the lips 86a of the keeper frame 80. The frame 180 is solid along the portions backing up the friction band end portions and thus it does not have the recesses 85 to accommodate the

shock absorbing blocks

93 and 94. The friction band 25 is supported around the inside of the keeper frame 180 and has the same shape or configuration as in the keeper frame 80. The keeper 13A functions in the same way as the keeper 13 except that its end portions do not have the same shock absorbing qualities as provided by the

blocks

93 and 94. Thus, the keeper 13A is preferred under conditions where repeated severe slamming is not expected.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A latch for releasably securing together separable parts comprising: keeper means having an inwardly flared opening therein supported by one of said parts; latch means supported by the other of said parts including pivotally supported latch arms means movable into said opening and having a swingable free end portion releasably engageable with said flared opening in said keeper means for releasably securing said parts together, said latch arm means being biased to swing said free end portion into a latching position engaging said keeper means in said opening and being movable to swing said free end portion to a release position relative to said keeper; said opening in said keeper having an inwardly concave arcuate friction surface portion facing said latch arm means and engageable by the swingable end portion of said latch arm means over a predetermined distance of travel of said latch arm means along said arcuate friction surface within said keeper for holding said latch arm means against release between an initial latching position and a fully latched position within said keeper.

2. A latch of the character defined in claim 1 including a convex lip portion provided by said keeper defining an entrance portion of said keeper and merging with said concave friction surface and providing a lock surface for holding said latch arm means against release from said keeper when the swingable end portion of said latch arm means is biased outwardly to engage the lock surface within said keeper.

3. A latch of the character defined in claim 1 including shaft means rotatably supporting said latch arm means, crank means on said shaft means, and cam means engageable with said crank means for rotating said shaft means to pivot said latch arm means from a latching position to a release position.

4. A latch of the character defined in claim 1 wherein said latch arm means comprises a pair of spaced latch arms mounted to swing the free end portions thereof away from each other to positions for engaging said concave friction surface within said keeper means for securing the latch means and keeper in latched condition and to swing said free end portions inwardly toward each other 10 for entrance into and release and removal from said keeper means.

5. A latch of the character defined in claim 1 wherein said free end portion of said latch arm means is slidable along said concave arcuate friction surface portion from said initial latching position to said fully latched position while engaging said friction surface portion to hold said latch arm means against movement along said friction surface toward withdrawal from said keeper at any position between said initial latching position and said fully latched position and said free end of said latch arm means is swingable out of engagement with said friction surface portion for movement out of said keeper responsive only to pivotable movement to such position disengaged from said friction surface portion.

6. A latch of the character defined in claim 5 wherein said latch arm means engages said friction surface at an angle with respect to a line drawn normal to said friction surface at said point of contact of said latch arm means with said friction surface portion less than the friction angle between said latch arm means and said friction surface portion whereby said latch arm means is held within said keeper between said initial latching position and said fully latched position by friction between said latch arm means and said friction surface portion.

7. A latch for releasably securing together separable parts comprising: keeper means supported by one of said parts, said keeper means having an inwardly flared recess partially defined by opposed arcuate concave internal friction surface portions and having a mouth portion leading to said recess for insertion and withdrawal of latch means; latch means on the other of said parts including a pair of spaced pivotally supported latch arms each adapted to pivot about an axis movable into said recess and oriented substantially perpendicular to the direction of movement of said latch arm during insertion into and withdrawal from said recess of said keeper, said latch arms having free ends pivotally swingable toward each other for in sertion into and withdrawal from said recess and swingable outwardly apart from each other for latching within said recess, said free end portion of each of said latch arms being engageable with a friction surface portion between its pivotal support and the mouth portion of said recess of said keeper for holding said latch arms against release therein when in expanded position within said recess; a rotatable shaft connected with each of said latch arms, said shafts being disposed within said second part; means supported within said second part for rotat ing said shaft to pivot said latch arms from latched to release positions, and resilient biasing means between said shafts for biasing said latch arms pivotally apart to latching positions.

8. A latch of the character defined in claim 6 wherein said shafts of said latch arms are disposed substantially parallel with each other, said means for rotating said shafts comprises a cam rotatably supported between said shafts and said shafts each include crank means engageable by said cam for rotating said shafts to pivot said latch arms between latching and release positions.

9. A latch of the character defined in claim 7 wherein said keeper means includes spaced lip portions defining said mouth portion leading to said recess, each of said lip portions serving a latch arm stop function and holding each of said latch arms against withdrawal from said recess independently of friction at an initial latched position within said recess.

10. A latch for releasably connecting separable parts comprising: a keeper in one of said parts having an inwardly enlarged locking recess provided with opposed concave arcuate friction surfaces; a latch assembly on the other of said parts including a pair of pivotally mounted oppositely swingable latch arm members having swingable free ends biased outwardly away from each other into engagement with one of said friction surfaces of said keeper recess when said latch members are within said recess in the releasable locked relationship of said parts;

said concave curvature of said arcuate friction surfaces being so related to the pivotal mounting and length of said latch arms that said free ends engage said friction surfaces between the pivotal mounting of said latch arms and the opening into said recess and when said free ends of said latch arms engage said friction surfaces said arms are each disposed at such an angle with respect to a line drawn normal to the friction surface engaged by said free end of said latch arm at the point of contact of said free end of said latch arm with said friction surface that said latch assembly is wedged further inwardly into said recess toward a fully latched position of said parts.

11. A latch of the character defined in claim 1 wherein said keeper means includes means for wedging said latch means fully in the latched position responsive to vibratory movement of one of said separable parts.

12. A latch as defined in claim wherein one of said parts is a door frame and another of said parts is a door adapted to swing into and out of closed relationship with said frame.

13. A latch of the character defined in claim 7 wherein said free end portion of said latch arms are each slidable along one of said concave arcuate friction surface portions from said initial latching position to said fully latched position while engaging said fricton surface portion to hold said latch arm against movement along said friction surface toward withdrawal from said keeper at any position between said initial latching position and said fully latched position, said free end of said latch arms are swingable out of engagement with said friction surface portions for movement out of said keeper responsive only to pivotable movement to such position disengaged from said friction surface portions.

14. A latch of the character defined in claim 13 wherein said latch arms engage said friction surface at an angle with respect to a line drawn normal to said friction surface at said point of contact of said latch arm with said friction surface less than the friction angle between said latch arm and said friction surface whereby said latch arms are held within said keeper between said initial latching position and said fully latched position by friction between said latch arms and said friction surfaces.

References Cited UNITED STATES PATENTS 363,684 8/ 1887 Phillips 292-224 573,934 12/1896 Trepte 131 1,774,091 8/1930 Glowe et al. 220- 46 2,445,285 7/ 1948 Wortian 292-49 2,717,794 9/ 1955 Wolfe 292124 3,241,872 3/1966 Moore 292224 FOREIGN PATENTS 16,285 7/ 1913 Great Britain. 81,889 6/ 1956 Netherlands.

RICHARD E. MOORE, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R. 292341.11, 341.13