US 3674297 A
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United States Patent Hawkins  INTERIOR DOOR LOCK  Inventor: Donald B. Hawkins, P.0. Box 221, San
Leandro, Calif. 94577 22 Filed: Jan. 21, 1971 211 App1.No.: 108,319
[ 1 July4,1972
Primary Examiner-Robert L. Wolfe Attorneyl-larris Zimmerman [5 7] ABSTRACT An extremely simple yet tamperproof lock including a plate member adapted for securance to a door jamb and a latch member movable away and towards the plate member. In the extended position of the latch member a door hinged to the jamb may not be swung inwardly since it will engage the latch member. The lock further includes a ball which must be raised and permitted to enter a ball receiving portion of the plate member in order to permit return of the latch member to its retracted inoperative position. When the latch member is moved outwardly into its locking or operative position, the ball gravitally falls downwardly and] prevents return of the latch member until the ball is manually raised.
5 Claims, 4 Drawing Figures PATENTEDJUL '4 m2 FNVENTOR. DONALD 5. HAWKINS BY AZ QD ATTORNEY INTERIOR DOOR LOCK BACKGROUND OF THE INVENTION Interior door locks have long been employed for example to prevent opening of a door even if the primary key lock has been forced or surreptitiously unlocked. Heretofore such interior locks have been relatively complex and/or have contained moving parts highly susceptible to wear and fatigue after extended use. Of more importance, these locks have generally been quite admissive to tampering.
SUMMARY OF THE INVENTION The present invention relates to an interior door lock which is extremely simple, contains moving parts which are negligibly susceptible to wear and fatigue failure, and is tamperproof.
In the accomplishment of the foregoing and other features and advantages, a lock in accordance with the present invention includes a plate member adapted for securance to a door jamb, a channel shaped latch member mounted for translation relative to the plate member between an inoperative position wherein one side leg of the latch member is in parallel engagement with one face of the plate member and an operative locking position wherein the opposite side leg of the latch member is in parallel engagement with the opposite face of the plate member, the latch member in its inoperative and operative positions being respectively in non-obstructing and obstructing relation to pivotal movement of a door hinged within the jamb, and a ball manually movable through a ball receiving portion of the plate member from a gravitally oriented locking position between the first side leg of the latch member and first face of the plate when the latch member is in its operative position to an unobstructed position permissive to translation of the latch member to its inoperative position.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a lock in accordance with the invention as secured to a door jamb, the latch member of the lock being depicted in its operative locking position.
FIG. 2 is a front elevational view of the lock, the left and right hand portions of the Figure respectively depicting the latch member of the lock in its inoperative and operative positions.
FIG. 3 is a plan view of the lock wherein the left and right hand portions respectively depict the latch member in its in.- operative and operative positions.
FIG. 4 is a sectional view taken at line 4-4 of FIG. 2, illustrating particularly the plate member of the lock.
PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a lock 11 in accordance with the present invention arranged for association with a door jamb 12 to prevent inward opening of a door 13 hingedly secured within the jamb. The lock includes a plate member I4 adapted for securance to the jamb 12 as by means of wood screws 16 extending thereinto through holes 17 provided in the plate member. In the illustrated case, the plate member is flat so as to be securable to the inside surface of the door jamb 12 with an end portion 18 projecting outwardly beyond the front surface of the jamb at right angles thereto as well as to the front surface of the door 13. However, in other embodiments, the plate member may be of L-shaped configuration in order that it may be secured to the front surface of the jamb with an angular end portion projecting right-angularly outward therefrom in similar relation as the end portion 18 The lock 11 further includes a latch member 19 mounted for translation transversely of the projecting end portion 18 of plate member 14 between an inoperative position in unobstructing relation to inward swinging of the door 13, and an operative locking position in obstructing engagement with the operativelocking position is facilitated in a novel manner by means of a ball 21 (see for example FIG. 2). The ball is manually movable from a gravitally oriented locking position restrictive to movement of the latch member from its operative position, through a ball receiving portion 22 of plate member 14 to an unobstructing position permissive to movement of the latch member into its inoperative position in a manner subsequently described.
Considering now the lock in more detail, particularly as to the latch member 19 and the manner in. which the ball 21 is arranged to selectively retain same in locked position, it is to be noted that the latch member is preferably of channel shaped configurationdefined by parallel spaced side legs 23 and 24 and a right-angularly interconnecting web 26. The web 26 slidably extends through a transverse slot 27 provided in end portion 18 of plate member 14 at a position inwardly spaced from its end edge and substantially flush with the surface of the door 13. The side legs 23 and 24 project outwardly away from the door jamb and door and are parallel to end portion 18 of the plate member 14. The side leg 23 proximal the door is preferably of greater length than the side leg 24 proximal the jamb. With the latch member thus slidably mounted on the plate member, the inoperative position. of the latch member is determined by side leg 23 being in parallel engagement with the adjacent face of plate member end portion 18 while side leg 24 is in parallel spaced relation. to the opposite face thereof, as shown in the left hand portions of FIGS. 2 and 3. Conversely, the operative locking position of the latch member is determined by side leg 24 being in parallel engagement with the adjacent face of end portion 18 while side leg 23 is in parallel spaced relation to the opposite side face thereof, as shown in the right hand portions of FIGS. 2 and 3. At this time, the web 26 will be noted to be in obstructing engagement with the door 13 to prevent inward opening thereof.
Retention of the latch member I9 in operative locking position by means of the ball 21 is then accomplished by the ball being disposed between the latch member side leg 23.and the plate member end portion 18 to therebyprevent movement of the latch member into its inoperative position. More particularly, the ball receiving portion 22 of plate member. 14 is preferably defined by an elongated transverse guide slot 28 in end portion 18 at a position forwardly spaced from the web receiving slot 27, which guide slot 28 includes an enlarged substantially circular portion 29 upwardly spaced from its lower end. The width of the guide slot 28 is less than the diameter of the ball 21 but sufficient to permit a surface portion of the ball to extend thereinto. The portion 29 is larger than the diameter of the ball such that the ball may be passed therethrough. In addition, the diameter of the ball is slightly greater than thespacing between the latch member side legs 23 and 24 less the thickness of plate end portion 18, i.e., slightly greater than the distance between a side leg and adjacent face of the plate end portion when the latch member is in either of its extreme inoperative and operative positions. It will be thus appreciated that with the components so relatively proportioned, when the latch member is in its operative position the side leg 23 serves to retain the ball against the guide slot 28 with a portion of the ball surface penetrating the slot. The ball is movable vertically along the guide slot and is normally gravitally oriented to its lower end which serves as a stop. With the ball thus positioned, movement of the latch member into its inoperative position is prevented and the latch member is thereby locked in operative position. To release the latch member, the ball is manually moved upwardly along the guide slot into alignment with the enlarged portion 29, whereupon the latch member may be moved to its inoperative position, the ball passing through the enlarged portion in the process. The ball then gravitally falls along the slot to its lower end, as shown in the left hand portion of FIG. 2, the side leg 24 now retaining the ball against the slot with a portion of the ball surface penetrating same. As thus positioned, the ball prevents the latch member from being moved to its operative position.
door as shown in FIG. I. Retention of the latch member in its However, it is only necessary to manually move the ball upwardly into alignment with the enlarged portion 29 of the slot to permit movement of the latch member into its operative position. The ball then gravitally falls downward to the lower end of the slot while bearing against the side leg 23 in the manner previously described to lock the latch member in operative position, as shown in the right hand portion of FIG.
There is thus provided by the present invention an extremely simple interior door lock having two moving parts, i.e., the latch member 19 and the ball 21. Neither of these moving members is particularly susceptible to wear such that long life of the lock is assured. Moreover, when the latch member is in its operative locking position, the ball is substantially inaccessible from the exterior of the door, thereby rendering the lock tamperproof.
It should be understood that while the lock of this invention is described in connection with a door jamb and door, it can likewise be used to releasably restrain movement of one member relative to another, e.g. a slidable drawer or the like. It should also be appreciated that the configuration of the lock permits the same to be used in a right or left hand manner.
1. A lock comprising a plate member adapted for securance to a door jamb, said plate member having an end portion adapted to project right-angularly outward from said jamb when said plate is secured thereto, said end portion having a ball receiving portion formed therein, a channel shaped latch member mounted for translation transversely of said end portion of said plate member between an inoperative position wherein one side leg of the latch member is in parallel engagement with one face of said end portion and an operative position wherein the second side leg of the latch member is in parallel engagement with the opposite second face of said end portion, said latch member in said inoperative and operative positions being respectively in non-obstructing and obstructing relation to pivotal movement of a door hinged within said jamb, and a ball manually movable through said ball receiving portion from a gravitally oriented locking position between said first side leg of said latch member and said first face of said end portion when said latch member is in said operative position to an unobstructed position permissive of translation of said latch member to said inoperative position.
2. A lock according to claim 1, further defined by said ball receiving portion being a guide slot formed transversely of said end portion of said plate member, said slot having an enlarged portion upwardly spaced from its lower end permissive to passage of said ball therethrough whereby said ball may be raised from said lower end of said slot into alignment with said enlarged portion to permit translation of said latch member to said inoperative position with said ball passing through said enlarged portion and being gravitally oriented to the lower end of said slot between said second side leg of said latch member and second face of said end portion of said plate member.
3. A lock according to claim 2, further defined by an interconnecting web between said side legs of said latch member slidably traversing a second transverse slot formed in said end portion of said plate member.
4. A lock according to claim 3, further defined by said ball having a diameter slightly greater than the spacing between said side legs of said latch member less the thickness of said end portion of said plate member, said ball having a surface portion penetrating said guide slot.
5. A lock according to claim 4, further defined by said first side leg having a length greater than that of said second side leg.
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