US3799591A - Latch lock - Google Patents

Abstract

A latch lock which makes possible, when opening a door, to release the latch by a simple operation without the necessity of turning a knob or the like. The lock has a latch head with a grooved boss fitting into a case. The latch head is urged outwardly of the case by a spring, and has a shape which enables it to be turned and also advanced and withdrawn freely. A stop is provided which is engageable with the grooved boss to prevent the latch head from turning when the stop is engaged.

Description

United States Patent 1 Taniyama Mar. 26, 1974 LATCH LOCK [75] Inventor: Mitsumasa Taniyama, Osaka, Japan [73] Assignee: Goal Lock Company, Osaka, Japan [22] Filed: May 9, 1972 21 Appl. No.: 251,759

[52] US. Cl. 292/71, 292/64 [51] Int. Cl. E05c 5/02 [58] Field of Search 292/63, 64, 65, 66, 67, 292/71, 201

[56] References Cited UNITED STATES PATENTS 202,474 4/1878 Ruggles 292/63 1,199,199 9/1916 Mason 292/201 2,482,959 9/1949 Anderson et a]. 292/63 Primary Examiner-Richard E. Moore Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [5 7] ABSTRACT A latch lock which makes possible, when opening a door, to release the latch by a simple operation without the necessity of turning a knob or the like. The lock has a latch head with a grooved boss fitting into a case. The latch head is urged outwardly of the case by a spring, and has a shape which enables it to be turned and also advanced and withdrawn freely. A stop is provided which is engageable with the grooved boss to prevent the latch head from turning when the stop is engaged.

1 Claim, 8 Drawing Figures LATCH LOCK The present invention relates to a latch lock which locks a door securely, and more particularly relates to a latch lock with which it is possible, when opening the door, to readily unlock the latch by a simple operation without the necessity of providing a mechanism, as required with the conventional latch locks, for with drawing the latch head by turning a knob, and which provides a means to securely lock the door when closing it.

An object of the present invention is to provide an improved latch lock having an altogether new mechanism which is not to be found with latch locks hitherto in existence, whereof the manufacturing cost is low, and which is simple to operate.

Another object of this invention is to provide a latch lock with which, when closing the door, it is possible, unlike with the conventional latch locks, to lock the door completely like with a genuine lock, whereas, when opening the door, a stop plunger, which serves to stop the latch head by engaging it, is lifted out of engagement thus making it possible to open the door without turning a knob but rather by rotating the latch head against the resilient force of a spring.

A further object of the invention is to provide a latch lock which, in an emergency, by means of a solenoid mechanism connected to detecting devices such as a fire alarm, a smoke detector or the like lifts the aforementioned stop plunger, and unlocking is effected by merely rotating the latch head as the door is opened.

A still further object of the present invention is to provide a latch lock having few parts and having a simple structure, and which is therefore inexpensive and well suited for mass production.

These objects are attained by an improvement in the combination of the constituent parts of the present invention and by their operation and an embodiment of the invention is provided in the accompanying drawings and a detailed description which follows.

According to the present invention, a latch head is fitted into a lock case, with an interposed spring, so as to be capable of advancing and withdrawing freely. The latch head is provided, on boththe upper and lower sides, with a groove the bottom of which slopes from the fore down toward the rear; and a stop plunger for preventing the latch head from rotating, is fitted, with an interposed spring, into the said groove in a manner such that the stop plunger can move up and down as the occasion demands and such that its end touches the bottom slope of the groove.

By virtue of the aforementioned mechanism, the door, when closed, cannot be opened since the stop plunger fits into the groove of the latch head and prevents it from rotating; lifting the stop plunger enables the latch head to rotate and withdraw so that the door can be opened.

In the accompanying drawings:

FIG. 1 shows an oblique view of the latch head to be used for the latch lock in question;

FIG. 2 is a front elevation of the said latch head;

FIG. 3 is a rear view of the same;

FIG. 4 is a plan of the same;

FIG. 5 is a sectional view of the latch head, across the 5 5 line shown in FIG. 2.

FIG. 6 is a cross section of a lock case fitted with the latch lock in question, sectioned across the line 6 6 as shown in FIG. 7;

FIG. 7 is a longitudinal section of the said lock case, across the line 7 7' as shown in FIG. 6; and

FIG. 8 is a cross-sectional view of the same, across the 8 8' line shown in FIG. 7.

The invention will now be explained in further detail with reference to the drawings:

The latch head 10 is approximately rhombiform in plan and consists of two parts, although it is of a unitary construction, i.e., the tongue, which has an oblique and curved side 11, and the boss 12. The upper and lower sides of the boss are each provided, at their respective centers, with a groove 13 whereof the bottom slopes from the rear end up toward the fore, and further a cut is made into the rear of the boss, at its center, so that there will be formed a curved bearing surface 14 against which a spring shoe is to hear.

The latch head 10 is fitted, with an interposed spring 17 into a lock case 16, the distance between the side plates 15 and 15' of the case 16' being approximately equal to the width of the said latch head, so that the latch head is able to advance and withdraw freely; and a stopper, shown as a stop plunger 18 is fitted, with an interposed spring 19, to the said side plates of the lock case so as to be capable of moving up and down and so that one end touches the sloping bottom of the groove 13 as mentioned above.

The numeral 20 indicates the side of the latch head which engages the catch and fastens the door; and the numeral 21 denotes the front plate of the lock case 16, through which an outlet 21a is bored for the tongue of the latch head, the outlet being approximately the same shape as, and serving as the primary guide for, the tongue.

The numerals 22 and 23 represent the guide plates, fixed to the side plates 15 and 15' of the lock case, for the latch head; the numeral 24 denotes a spring shoe fastened to the back plate 25 of the lock case; and 26 represents another spring shoe having bends 26a and 26b as guides and touching the curved bearing surface 14 of the latch head, impelled by the resilient spring 17.

The numeral 27 indicates a plate, fixed to the side plates of the lock case, having a hole through which the stopplunger 18 is inserted. The numeral 28 represents a stopper, attached to the rear end of the said stop plunger, which prevents the stop plunger from falling and to which is connected a solenoid mechanism 30 by means of solenoid shaft 31 for lifting it. Numeral 29 represents a spring shoe which is fastened to the stop lever.

Now turning to the operation of said latch lock, FIG. 6 shows it in a locked condition, that is to say, the tongue of the latch head 10 is sticking out of the lock case, impelled by the resilient force of the spring 17, while the boss 12 limits its maximum extension.

When a door fitted with the subject latch lock closes, the curved, oblique side 11 of the tongue of the latch head hits against the curved part of a strike (not shown) provided in the door case, and since this hitting force is converted, by virtue of the said oblique side, into a force which works in the orthogonal direction, the latch head starts to withdraw, over coming the resilient force of the spring 17.

As the latch head withdraws, the sloping bottom of the groove 13 provided on the upper side of the boss 12 at its center, pushes the stop plunger 18 up, overcoming the resilient force of the spring 19 and therefore the latch smoothly withdraws, without any hitch whatever, until an unlocked condition is reached. Once the latch head passes over the said curved part of the strike and falls into the catch-hole of the strike (not shown), it again extends by virtue of the resilient force of the spring, thus locking the door. (At this point of time, the stop plunger 18 will also have regained its original position, impelled by the resilient force of the spring 19.)

As long as the latch lock remains in an extended condition, the door will not open even if a force is applied in an attempt to open it since while the latch head will attempt to rotate on the fulctrum of the corner a of the boss 12, the stop plunger 18 with the side b of the groove 13 on the upper side of the boss and prevents the latch head from turning, thus keeping the door locked.

When, however, the stopper 28 of the stop plunger 18 is connected with a lifting mechanism operated by means of a sliding thumbturn, solenoid, or the like, the stop plunger 18 is, as it is lifted, disengaged from the side b of the groove; and so, as a force is applied in the direction of opening the door, the latch head rotates on the fulcrum of the corner a of the boss, as is illustrated in FIG. 8.

As additional force is exerted in an attempt to open the door, the engaging side 20 of the latch head works likewise as the curved bearing surface 14 and the latch head retracts into the lock case and thus the door is unlocked.

Thereafter, the aforementioned operation is repeated every time the door is opened and closed.

As will be seen from the foregoing description, the latch lock according to the present invention requires no latch-retracting mechanism which operates in connection with a knob since, when being locked, the latch head withdraws through the medium ofa spring. Therefore it is inexpensive to manufacture.

Furthermore, since the latch lock can be unlocked by simply lifting the stop plunger, it may be employed to great advantage, by connecting it with a solenoid mechanism, as an emergency lock that is to say, one which can be readily unlocked in an emergency, the stop plunger disengaging in response to the operation of detecting devices such as a fire alarm, smoke detector, or the like.

As such, the latch head of the present invention has a very wide application.

It is to be clearly understood that the scope of the claim of the present invention is by no means restricted to the aforementioned embodiment thereof but that some variations and modifications come under the scope of claim of the present invention.

What is claimed is:

l. A latch lock for a door, comprising:

a lock case defining an aperture at one end thereof;

a latch head having a boss defining an engaging groove therein operatively positioned within said lock case and a tongue extending outwardly through said aperture, said boss having an end rear portion and a centrally located front portion;

a spring interposed within said lock case between said latch head and the end of said lock case opposite the end of said case defining the aperture, said latch head and spring being arranged such that said latch freely advances and withdraws relative to said lock case and rotates about a corner of said boss;

a stop operatively positioned for engaging in and disengaging from said latch head engaging groove, said groove downwardly sloping from the front portion of the boss toward the back portion of the boss such that said latch head withdraws and then advances without rotation when closing said door when said stop is in engagement with said latch lock groove and said latch lock being restrained from rotation when engaging said stop, thus preventing a locked door from opening when said stop and said latch head are in engagement.

Claims (1)

1. A latch lock for a door, comprising: a lock case defining an aperture at one end thereof; a latch head having a boss defining an engaging groove therein operatively positioned within said lock case and a tongue extending outwardly through said aperture, said boss having an end rear portion and a centrally located front portion; a spring interposed within said lock case between said latch head and the end of said lock case opposite the end of said case defining the aperture, said latch head and spring being arranged such that said latch freely advances and withdraws relative to said lock case and rotates about a corner of said boss; a stop operatively positioned for engaging in and disengaging from said latch head engaging groove, said groove downwardly sloping from the front portion of the boss toward the back portion of the boss such that said latch head withdraws and then advances without rotation when closing said door when said stop is in engagement with said latch lock groove and said latch lock being restrained from rotation when engaging said stop, thus preventing a locked door from opening when said stop and said latch head are in engagement.

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