US3917329A

US3917329A - Lock

Info

Publication number: US3917329A
Authority: US
Inventors: Masaru Fujiki; Masahiro Yoshida; Hiroshi Fukuda
Original assignee: Pioneer Audio Corp
Current assignee: Pioneer Audio Corp
Priority date: 1972-07-31
Filing date: 1973-07-30
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04
Also published as: IT991464B; GB1419710A; DE2338806A1; FR2200877A5

Abstract

A lock comprises a latch bolt, a working member to be retracted into the lock when a door is closed, a spring for retracting the latch bolt and a spring for returning the latch bolt so repulsive energy is accumulated in the springs by the working member, and a release member for releasing the accumulated energy in the springs. By this releasing of energy, the latch bolt is moved to a retracted position to be unlocked. When the door is opened, another accumulated energy is released, the latch bolt and the working member return to their original projected positions. A casing for the lock comprises an inner casing inserted in notched portions of the door, a pair of outer casings having nipping portions which are touchable with marginal portions of opening of the notched portion, and attaching members to attach the outer casings to the inner casings. The outer casings are attached to the inner casings so as to put the marginal portions of opening of the notched portion strongly between their nipping portions.

Description

iJnited States Patent [1 1 Fujiki et a1.

[ Nov. 4, 1975 1 LOCK [75] Inventors: Masaru Fujiki; Masahiro Yoshida,

both of Tokyo; Hiroshi F ukuda, Yoshikawa, all of Japan [30] Foreign Application Priority Data July 31, 1972 Japan 47-90235 Aug. 5, 1972 Japan 47-92358 Oct. 24, 1972 Japan 47-122710 Apr. 14, 1973 Japan 48-42547 [52] US. Cl. 292/163; 70/141; 70/448; 292/169.l3; 292/177, 292/181; 292/D1G.- 37

[51] Int. Cl. EOSC l/08 [58] Field of Search 292/DIG. 37, 37, 177, 181, 292/163, 169.13, 41; 70/107, 111, 150, 141,

FOREIGN PATENTS OR APPLICATIONS 26,660 11/1902 Switzerland ..292/177 358,922

Primary ExaminerRoy D. Frazier Assistant ExaminerPeter A. Aschenbrenner Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato', Bruce L. Adams [57] ABSTRACT A lock comprises a latch bolt, a working member to be retracted into the lock when a door is closed, a spring for retracting the latch bolt and a spring for returning the latch bolt so repulsive energy is accumulated in the springs by the working member, and a release member for releasing the accumulated energy in the springs. By this releasing of energy, the latch bolt is moved to a retracted position to be unlocked. When the door is opened, another accumulated energy is released, the latch bolt and the working member return to their original projected positions. A casing for the lock comprises an inner casing inserted in notched portions of the door, a pair of outer casings having nipping portions which are touchable with marginal portions of opening of the notched portion, and attaching members to attach the outer casings to the inner casings. The outer casings are attached to the inner casings so as to put the marginal portions of opening of the notched portion strongly between their nipping portions.

8 Claims, 17 Drawing Figures 3/1938 ,ltaly 292/177.

U.S-. Patent Nov.4, 1975 'Sheet1of6 3,917,329

US. Patent 'Nov. 4, 1975 Sheet 2 of6 3,917,329

lhlln U.S. Patent Nov. 4, 1975 Sheet 3 0f 6 FIG.

FIGJG r "1 J 319321317 La "w 314 L1 320 12 LJ/ U.S. Patent Nov. 4, 1975 Sheet 5 of6 3,917,329

US Patent Nov. 4, 1975 Sheet 6 of6 LOCK BACKGROUND OF THE INVENTION This invention relates to a lock and its structure, particularly to a lock which may be temporarily latched or locked, and especially to a lock which may be easily op SUMMARY OF THE INVENTION It is an object ob the invention to provide anovel lock which may be locked and unlocked by simple operation, and may be economically manufactured with few materials, process and hands, etc.

Another object of the invention is to provide a communicator which communicates the unlocking at the same time it is done by mere button operation.

Still another object of the invention is to provide a casing for a lock which may be simply attached to a door and the like. v

The lock according :to the present inventioncomprises in combination a latch bolt which may' be operated to a retracted position, a spring means, in which energy is accumulated so as to move the latch boltto the retracted position, a workingmember which contributes to accumulate energy in the spring means, and a releasing means to release the energy accumulated spring means and to retract the latch bolt for unlocking. The lock is provided with a push button, and further provided with a switch operated by the push botton and a communicator circuitly connected with the switch. I

The casing in the lock has an inner casingand an outer casing to be attached to the inner casing, and the outer casing has nipping portions projecting from its periphery so as to put the door between them to be attached to the door.

Other and further objects, function and effect of the invention will be apparent from the following embodiments and the features thereof will be pointed out particularly in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is a sectional view taken along 4 4 line of FIG. 2 partly broken, showing a state of a cover and a a thumb turn being attached.

FIG. Sis a perspective view ofa trigger means in FIG.

1, which is partly broken. V J

FIG. 6 is a plan view partly broken, showing an example of holding a latch bolt of the lock.

FIG. 7 is a sectionalview taken along 7 7 lineiof FIG. 6.

FIG. 8 is a sectional view of another embodiment of the lock according to the present invention, which is partly broken.

FIG. 9. is a sectional view taken along 9-9 FIG. 8.

line of FIG. 10 is a sectional view taken along l0l0 line of FIG. 8, which is partly broken. r I

FIG. 11 is a sectional view taken along'11ll line of FIG. 8, showing a state of an inner casing and a thumb turn being attached. 7 l

FIG. 12 is aperspective view, showing an external form of the lock in FIG. 8. l

FIG. 13 is a sectional view partly broken, showing a locked state of another example according to the present invention. r

FIG. 14 is'a sectional view partly broken, showing an unlocked state of the lock in FIG. 13. I

FIG. 16 is a sectional view taken along l6 l6 line' of FIG. 15.

, variant of the lock in FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 to FIG. 7 inclusive, an embodimentof the lockacccor'ding to the present invention is' shown'.

A' front 2 of a casing'l and an armored plate 4 are provided with rectangular holes Sand 6 practically in parallel and vertically. In thehole 5, a latch head 7 is reciprocatably arranged a'ndis integrally attached to' a latch bolt 9 by a set-screw 8.

The latch bolt 9 is slidably passed through a support the side of head 7 from the supporting plate 10. Since" a stopper 15 provided on the latch bolt 9 is abutting on a surface 16 of the bent portion, the latch bolt may be moved to a retracted position by the sliding of the interlockingrnember 13 through thesto pp e'r 15. Between the latch head 7 and the bent portion 12, there is a latch spring 17 wound on the outer periphery of the latch bolt 9 to urge the bolt in the forward direction to project from the front 2. On the other hand, a working member 18 having nearly the same shape as the latch head is reciprocatably arranged in the hole 6 and its end 19 and an extension'20 of the bent portion 12 are provided with spring holders 2] and '22 oppositely and practically in parallel with the latch bolt, and a compression coil spring 23 for retraction'is connected between the holders. v

A working piece 25 having nearly L-shape is fixed by a set screw 26 on a side 24 of the working member, which extends practically in parallel with the spring 23 for retraction of the latch bolt, and a bent tip portion 27 of the member comes'in contact with the outside of extension of the interlocking member 13.

On the tip portion 27 and the side wall 28 of the casing, there are provided

spring holders

29 and 30 oppositely and practically in line with the spring 23, and a compression coil spring 31'is connected for retraction.

The

springs

23 and 31 may be changed, instead of the I compression springs with, for instance, tension'springs provided between the extension 20 ofthe interlocking member 13 and the tip portion 27 of theworking'piece 25 as well as between fixing members for the front or the like and the extension of the interlocking member, and further the

springs

23 and 31 may be arranged in FIG. 15 is a vertical sectional view of the lock parallel and their kinds ofspring and their positions may be suitably fixed.

A trigger 33 or release member serving as an actuator mechanism with the interlocking member 13, comprises a main body 33 which is bent into a box-like

member having extensions

34, 34, and around a pair of pivots 35 provided on the main body, the trigger is rockably attached to the casing.

The extensions of the trigger are provided with shoulders at notched portions, which are normally engaged with projections 37 provided on the extension 20 of the interlocking member 13 to prevent the movement of the member. A tension coil spring 38 is hooked in fitting holes 39, 40 which are respectively provided on one side of the main body of the trigger and the side wall 28, thus one side of notched portion of the trigger is pushed against the shoulder of the interlockingmember.

Another side portion 41 of the main body of the trigger is symmetrically provided with projections 44, 45 having slant faces 42, 43 of same shape in the longitudinal direction, and these projections are abutting with a notched portion 48 which has a slant face 47 provided on a reciprocating shaft 46 that is extending so far as outside of the casing, and both ends of the reciprocat ing shaft are furnished with a push button respectively.

The sliding piece 11 of'the interlocking member has a bent projection 50 at its tip and is slidably inserted in a guide groove 51 of the casing, and projections 52, 53, which are provided on the upper and lower sides of the tip of extension of the interlocking member and of the tip portion of the working piece, are moved by the guide of guiding groove 54 of the casing.

In FIG. 1 which shows the opened-door state, the latch head 7 and the working member 18 are projecting from the casing fixed to a door 55 by a set-screw 56, and at the time of door closing, as shown in FIG. 2, the latch head abuts against a strike 59, which is fixed to a frame 57 of the door by a set-screw 58, and the latch bolt is once pushed inwardly of the casing, but is returned to its original position by the latch spring and is inserted into a hole 60 provided in the strike and a re-' cess 61 provided in the frame of door. On the other hand, the working member abuts against the strike and is pushed back inwardly of the casing so that the spring 23, for retracting the latch bolt, is compressed between the interlocking member blocked by the engagement of the trigger and the working member. Also, the spring 31, for returning, is compressed between the working piece 25 of the working member and the side wall 28.

Under such a state, if the push-button is pushed or pulled, the trigger rocks around the fulcrum of the pivotal shaft and the engagement between the shoulder portion of the extension of the trigger and the projection of the interlocking member is released, thus as shown in FIG. 3, the interlocking member is pushed back until it abuts on the tip of the working piece by the spring 23, so that the latch bolt is retracted with the interlocking member through the stopper 15 to become in the unlocked state.

Hereupon, if the door is opened, the working member and the latch bolt are pushed back to be returned to the original state. If a suitable compression spring (not shown) or the like is interposed between the pushbutton and the casing, the returning motion of the push-button may be effected more smoothly.

A dead bolt 62 is reciprocatably arranged througha.

hole 63 which is provided in the front and the armored plate,-similarly to the latch bolt, and a front portion 64 reciprocating through the hole is formed thick and a rear portion 65 is formed thin integrally, or laminating plate-shaped members to form a step portion 66 and further to form a guide pocket 68 in the rear portion. A thumb turn hub 69 is fixed to a shaft 70 so as to nip

cam plates

72, 73 having a cam portion 71 at upper and lower'sides, and a guide roller 74 is arranged between tip portions of the cam plates. The roller is guided in the pocket 68 and its one end is abutting against a pin 76 and pressed by a spring which is held against the dead bolt by a supporting shaft 77.

A dead locking lever 78 is rockably provided around I a pivotal shaft 79 as a fulcrum and its one end is abut ting against the dead bolt, and is pressed onto the dead 84) is turned, a flat tip portion 86 ofa thumb turn shaft (or a flat tip portion 88 of inner cylinder of a cylindrical key 87) is diagonally hooked on pins 89 90 which are studded oppositely in longitudinal direction of the shaft 70, thus the thumb turn hub is turned to project the dead bolt. The'r'eupon, the dead locking lever drops into the notchedportion 67 to prevent the movement of the dead bolt inwardly of the casing.

Incase of unlocking, the thumb turn, key, etc. is turned in the reverse direction, abutting the cam portion 71 of the cam plate against the pin 82 of the dead locking lever, pushing up the lever, disengaging the engagement with the dead bolt, thus to retract the dead bolt.

And, when the thumb turn, etc. is turned, a lever 91 rotatablyinserted in the periphery of the shaft 70'is pus'hedby the guide pin, abutting a tip portion 92 of the lever against a pin 94 which is studded in a rear portion 93 of the latch bolt, thus retracting the latch bolt against the latch spring, so that it is possible to use the.

back in such cases when the latch bolt is unlocked interlockingwith the dead bolt or the operation of pushbutton is wrong or the spring 23 or the stopper 15,'etc..

are damaged. The stopper 96 controls the position of In FIG. 6 and FIG. 7, there is shown an example in which the latch bolt may be used instead of dead locking by the dead bolt. A blocking means 98 abuts on the end portion of the latch'bolt to prevent the movement of the latch bolt. The blocking means is practically same as the thumb turn hub, wherein supporting

plates

99, 100 are attached with space to a shaft 70' which is rotatably pivoted on the casing; and i a roller 101 is bridgecl'between both of the supporting plates and the roller is abutting against inner peripheral face of an arecasing, thus the'projecting element is made to abut against the end portion of the latch bolt by turning operation of the thumb turn or the key, etc. to prevent the movement of latch bolt, and when the abutment is disengaged, it is possible to make the latch bolt movable,

where-upon a spring 105 presses the lever onto the roller. A stopper 106 controls the rocking range of the lever.

In FIG. 8 to FIG. 17 inclusive, there are shown other embodiments of the present invention and those parts corresponding to the above embodiment are indicated with addition of suffix a or b.

A latch spring 17a is wound around a latch bolt 9a between a latch head 7a and a casing 1a.

Both ends of an interlocking member 13a are formed annularly and their

annular portions

201, 202 are slidably fitted on a latch bolt 9aand a shaft portion 203 of the working member. On the annular portion 201 of the latch bolt side, a long groove 204 is provided, in which a stopper 205 fixed to the latch bolt by a set screw is inserted and the latch bolt is moved with the movement of the interlocking member.

A spring 23afor retracting the latch bolt, which is provided between a head portion 206 of a working member 18a and the annular portion 202 of the interlocking member, has a larger spring constant than the latch spring 17a, the repulsive force of the spring 23ais released against the repulsive force of the latch spring 17aand the latch bolt is moved to a retracting position with the interlocking member to be unlocked. In this case, repulsive force is accumulated in the latch spring, which force is released when the door is opened to return the latch bolt and the working member with the interlocking member to the original position. Hereupon, an auxiliary spring 207 may be provided between the casing and the interlocking member so as to return the interlocking member to the original position.

A main body of trigger 33ahas a projection 208, which is engaged with a hole 210 of an engaged piece 209 normally fixed to the interlocking member 13a. On both sides of the main body of trigger, slant projections 44a, 45a are provided outwardly of the casing so that a slant projection 47a ofa working rod 46a provided on a push-button 49a is engageable with the above projections.

The push-button is inserted in a notched hole 211 which is provided on the casing, and its working rod 46a is slidably supported by a supporting member 212 fixed to the casing.

On the working rod 46a, a compression spring 213 is provided, by which the push-button is normally energized outwardly of the casing.

On inner side of the casing, a switch 214 is provided and both ends of its movable metallic piece 215 and fixed metallic piece 216 are fixed through an insulator 217, and another end of the movable metallic piece contacts with the inner face of push-button.

To the

metallic pieces

215, 216, there are connected with an electric source (not shown), an alarm, such as a buzzer 218 or a bell or a lamp or the like, or a communicater 219, such as an indicator so that, when the push-button is pushed, a circuit 220 is closed by the switch at the same time with unlocking, which is informed by the communicator.

In case of preventing the movement of latch bolt under locked state, it is effected by the key or a thumb turn 83a.

The inner cylinder of a cylindrical key 87a has projecting

pieces

222, 223 which are outwardly projecting through a groove 221 provided on the outer cylinder of the cylindrical key, and one projecting piece 222 contacts with a lever 104a and another projecting piece 223 contacts with a bent piece 225 on one end of a lever 224 which is rockably pivoted on the casing.

Another end of the lever 224 engages with a shoulder portion 226 notched on the working rod 460 to prevent the working of push-button. On a thumb turn shaft a, there are attached projecting

pieces

222a, 223a corresponding to the projecting

pieces

222, 223.

An embodiment shown in FIG. 13 to FIG. 17 inclusive is a case, in which the latch bolt and the working member are arranged concentrically.

In a casing lb, there is provided a guide hole 301, in which a latch bolt 9b. and a working member 18b are reciprocatably arranged having a space 302 concentrically,

In the working member, a portion for inserting the shaft portion of latch bolt is formed into cylindrical shape and a portion for inserting the latch head is formed into square pipe shape.

At about the center of the working member and the latch bolt, there is provided through

grooves

303, 304 respectively corresponding to each other.

A stopper pin 305 is fixed to the latch bolt located at innerside of the casing than the through groove 304 so as to project outside from the through hole 303 of the interlocking member.

A washer 306 contacts with the stopper pin, and between the washer and a step portion 307, which is provided on end portion of the guide hole 301, a latch spring 17b is wound around outer periphery of the working member.

In the guide hole 301 on the side oflatch head, a ringshaped slider 309 having a step portion 308 at its inner end is slidably inserted, and one end of the slider contacts with both end portions of the stopper pin 305.

In the direction of the step portion of the slider, a through hole 310 is provided so as to intersect in right angle with the guide hole 301, and a guide pin 311 passed through the through

grooves

303, 304 is slidably inserted in the through hole 310. The length of the guide pin is in such a size that the pin can move with in the guide hole so that the latch bolt is moved to a retracting position with the movement of an interlocking member 312 inwardly of the casing. A spring 23b for retracting the latch bolt is wound around outer periphcry of the working member between a step portion 308 of the slider and a side portion 313 of a square pipe portion of the working member. A driver pin 314 contacts with one end of the guide pin, and holes 315, 316, in which the guide pin and the driver pin are reciprocatably inserted respectively, are arranged in the guide hole intersecting'therewith in right angle. In the casing, a through hole 317 communicating with the hole 315 such that nearly a right angle is formed, and a working rod 46b is inserted through the through hole.

On the working rod, there is a curved recess 318 at a position opposite to the hole 315, and between the recess and end face of the guide pin, a ball 319 is interposed having such a size capable of being inserted in the hole 315. A spring 320 inserted in the hole 316 always energizes the guide pin and the driver pin in the direction to the ball, and normally the movement of the guide pin in the guide hole is prevented.

Therefore, when a trigger means 321 is operated by pushing a push-button 49b, the guide pin is pressed by the pin to release the engagement between the hole 315 and the guide pin 311 as well as the engagement between the hole 316 and the driver pin 314, and by the release of the energized spring 23b for retracting the latch bolt, the guide pin 311 of the interlocking member is moved with the latch bolt 9b to its retracting position, as shown in FIG. 14, thus to be unlocked.

As shown in FIG. 17, the latch bolt and the working member may be reversed in their position. 322 denotes a step portion provided on inner peripheral face of an annular latch bolt, and 323 a washer contacting with a guide pin 311a.

In FIG. 8 to FIG. 12 inclusive, variants of the casing are shown. A pair of

inner casings

401, 402 are put together nearly at their intermediate portions so as to put an intermediate casing 403 between them, and the latch bolt and the working member, etc. are attached to the intermediate casing 403. In this case, the intermediate casing 403 and the inner casing 401 may be integrally formed, the intermediate casing may be eliminated or one of inner casings may be provided with a cover, while another inner casing may be omitted.

In the inner casing, positions for attaching the pushbutton and the key or the thumb turn are outwardly expanded to form a projecting portion 404. On the other hand, in a pair of

outer casings

405, 406, a notched portion 407, which being in such a size to be inserted by the projecting portion 404-, is provided nearly at the center of the casings, and the outer casings are attached on the outside of the inner casings so as to put the latter between the former to insert the projection in the notched portion. On outer periphery of the outer casing, a nipping portion 408 is formed, which is projecting outwardly to become slightly larger than the configulation of the inner casing.

When the present device is attached to a door 55a, both of the inner casings are covered with the outer casings, which are fixed by set screws or the like, and this assembly is inserted in a notched portion 410, which is notched in the door matching with the configuration of the inner casing, and the nipping portion of the outer casing is made to contact with a marginal portion of opening 411 of the notched portion to be tightened by a set-screw 409. In this manner the present device is rigidly fixed to the door by the nipping portion. In this case, the attachment may be adjusted by interposing a stay 4112 of suitable length between the inner casing and the outer casing corresponding to the thickness of the door. And, by forming integrally one of the inner casing, the intermediate casing and one of the outer casing, the device may be standardized. A hanging portion 413 is provided on upper portion of the outer casing at any suitable position.

The present invention is not to be limited to the above examples but can be modified within the scope of the spirit of the invention as indicated in the following claims.

What is claimed is:

l. A lock for latching a door, comprising in combination: a casing; a latch bolt and a working member reciprocatably supported by the casing and movable between a projected position wherein said latch bolt projects from said casing for latching the door and a retracted position wherein said latch bolt is retracted into said casing; an interlocking member having one end connected to the latch bolt and another end located on a line of action of the working member; latch spring means disposed between the interlocking member and the latch bolt and coacting with said interlocking member to bias the latch bolt in the direction of its projection; spring means for retracting the latch bolt and being interconnected between said another end of said interlocking member and the working member; trigger means for releasably blocking movement of the interlocking member in such a manner that a certain repul sive force is accumulated in said spring means for retracting the latch bolt as the working member is retracted when the door is closed, and upon releasing of the interlocking member, effecting release of the spring means for retracting the latch bolt so as to move the latch bolt to its retracted position; and another spring means disposed between the working member andthe casing and operable when the door is opened to return.

the latch bolt and the working member to the projected position.

2. A lock according to claim 1, further comprising a working piece extending from the side of said working member nearly in parallel with the latch bolt, and a bent piece having a tipportion bent so as to contact with the interlocking member; and compression coil springs between the tip of the working member and the.

lamp or the like connected with the switch member and operative to provide an indication that the latch bolt is unlocked.

5. A lock according to claim 1, further comprising an inner casing; a pair of outer casings having nipping portions formed so as to extend a suitable amount from the inner casing and being provided oppositely to both outsides of the casing; and fastening means for detachably fastening at leastone of the outer casings to the inner casing so as to nip the fixing portion of the door between both nipping portions of the outer casings.

6. A trigger means for a lock, comprising a casing; an

interlocking member movable within the casing and provided with a projection at a suitable position thereon; a trigger main body pivotally mounted in the casing and having on one side thereof a shoulder portion detachably engaged with the projection of the interlocking member and having on another side thereof a projection having a slant face; and a working rod provided with a projection having a slant face engageable with the slant face of said trigger main body.

7. A lock for latching a door comprising: acasing having a guide hole; a latch bolt and a working member concentrically and reciprocatably guided in the guide hole and movable between a projected position wherein said latch bolt projects from said casing for latching the door and a retracted position wherein said latch bolt is retracted into said casing and mutually formed telescopically; latch spring means disposed between the latch bolt and the casing to continuously bias the latch bolt towards its projected position; an interlocking member coacting with the latch bolt and inserted in a through groove extending to the guide hole of the casing; spring means for retracting the latch bolt; and trigger means for detachably blocking movement of the interlocking member so as to accumulate the repulsive force in the spring means for retracting the latch bolt as the working member is retracted, and for effecting release of the spring means for retracting the the spring means, and a further intersects a through hole in said casing at nearly a right angle therewith; a working rod inserted in the through hole and provided with a curved recess at a portion thereof where the through hole intersects said further hole; and a ball interposed between the recess and another end of the guide pin and acts so as to press the guide pin by the action of the working rod.

Claims

1. A lock for latching a door, comprising in combination: a casing; a latch bolt and a working member reciprocatably supported by the casing and movable between a projected position wherein said latch bolt projects from said casing for latching the door and a retracted position wherein said latch bolt is retracted into said casing; an interlocking member having one end connected to the latch bolt and another end located on a line of action of the working member; latch spring means disposed between the interlocking member and the latch bolt and coacting with said interlocking member to bias the latch bolt in the direction of its projection; spring means for retracting the latch bolt and being interconnected between said another end of said interlocking member and the working member; trigger means for releasably blocking movement of the interlocking member in such a manner that a certain repulsive force is accumulated in said spring means for retracting the latch bolt as the working member is retracted when the door is closed, and upon releasing of the interlocking member, effecting release of the spring means for retracting the latch bolt so as to move the latch bolt to its retracted position; and another spring means disposed between the working member and the casing and operable when the door is opened to return the latch bolt and the working member to the projected position.

2. A lock according to claim 1, further comprising a working piece extending from the side of said working member nearly in parallel with the latch bolt, and a bent piece having a tip portion bent so as to contact with the interlocking member; and compression coil springs between the tip of the working member and the side face of the interlocking member as well as between the bent piece and the side wall of the casing.

3. A lock according to claim 1, further comprising a push-button for actuating the trigger means.

4. A lock according to claim 1, further comprising a switch member; and an indicator such as a buzzer or a lamp or the like connected with the switch member and operative to provide an indication that the latch bolt is unlocked.

5. A lock according to claim 1, further comprising an inner casing; a pair of outer casings having nipping portions formed so as to extend a suitable amount from the inner casing and being provided oppositely to both outsides of the casing; and fastening means for detachably fastening at least one of the outer casings to the inner casing so as to nip the fixing portion of the door between both nipping portions of the outer casings.

6. A trigger means for a lock, comprising a casing; an interlocking member movable within the casing and provided with a projection at a suitable position thereon; a trigger main body pivotally mounted in the casing and having on one side thereof a shoulder portion detachably engaged with the projection of the interlocking member and having on another side thereof a projection having a slant face; and a working rod provided with a projection having a slant face engageable with the slant face of said trigger main body.

7. A lock for latching a door comprising: a casing having a guide hole; a latch bolt and a working member concentrically and reciprocatably guided in the guide hole and movable between a projected position wherein said latch bolt projects from said casing for latching the door and a retracted position wherein said latch bolt is retracted into said casing and mutually formed telescopically; latch spring means disposed between the latch bolt and the casing to continuously bias the latch bolt towards its projected position; an interlocking member coacting with the latch bolt and inserted in a through groove extending to the guide hole of the casing; spring means for retracting the latch bolt; and trigger means for detachably blocking movement of the interlocking member so as to accumulate the repulsive force in the spring means for retracting the latch bolt as the working member is retracted, and for effecting release of the spring means for retracting the latch bolt so as to move the latch bolt to the retracted position by the detachment of the interlocking member.

8. A lock according to claim 7 comprising a guide pin, a driver pin connected at one end of the guide pin; spring means contacting with the driver pin and biasing the driver pin in the direction of the guide pin; a casing having holes therein which extend at nearly a right angle to and intersect with the guide hole, said holes being dimensioned such that one receives therein the guide pin, another receives therein the driver pin and the spring means, and a further intersects a through hole in said casing at nearly a right angle therewith; a working rod inserted in the through hole and provided with a curved recess at a portion thereof where the through hole intersects said further hole; and a ball interposed between the recess and another end of the guide pin and acts so as to press the guide pin by the action of the working rod.