US3810667A

US3810667A - Latch

Info

Publication number: US3810667A
Application number: US00170232A
Authority: US
Inventors: T Dugan
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-08-09
Filing date: 1971-08-09
Publication date: 1974-05-14
Anticipated expiration: 1991-05-14

Abstract

A pick-proof latch for a closure, such as a door, having a keeper plate for attachment to the closure frame or jamb and a striker plate hinged to the keeper plate for movement to a locked closure-engaging position wherein the striker plate is located in the path of opening movement of the closure to lock the latter in closed position. The latch is released to open the closure by first raising the striker plate and then swinging the latter plate to a closure-releasing position. The keeper plate projects beyond the lower end of the striker plate in the locked closureengaging position of the latter plate and may have an abutment, such as a screw, to extend between the keeper plate and closure to prevent raising of the striker plate to release the latch by insertion of a card between the closure and its jamb or frame.

Description

United States Patent 191 Dugan 1451 May 14,1974

[ LATCH [76] Inventor: Thomas J. Dugan, 99 Avenida Serra, San Clemente, Calif. 92672 [22] Filed: Aug. 9, 1971 [2]] Appl. No.: 170,232

52 US. Cl. 292/346, 292/297 51 11m.c1. ..E05 3/14 58 Field of Search 292/346, 297, 298', 341.17,

[56] References Cited UNITED STATES PATENTS 893,463 7/1908 Denny et al. 292 297 1,727,323 9/1929 Bartlett 1 70/4l8 126,360 4/1872 Wheeler.... 292/206 2,794,665 6/1957 Sasse .1 292/341.17 x

Primary Examiner-Richard E, Moore Attorney, Agent, or Firm-Boniard I. Brown [57] ABSTRACT A pick proof latch for a closure, such as a door, having a keeper plate for attachment to the closure frame or jamb and a striker plate hinged to the keeper plate for movement to a locked closure-engaging position -wherein the striker plate is located in the path of opening movement of the closure to lock the latter in closed position. The latch is released to open the closure by'first raising the striker plate and then swinging the latter plate to a closure-releasing position. The keeper plate projects beyond the lower end of the striker plate in the locked closure-engaging position of the latter plate and may have an abutment, such as a screw, to extend between the keeper plate and closure to prevent raising of the striker plate to release the latch by insertion of a card between the closure and its jamb or frame.

7 Claims, 5 Drawing Figures 1. Field of the Invention This invention relates generally to closure latches of the kind commonly referred to as night latches. The invention relates more particularly to'a pick-proof latch of the kind having a hinged striker plate which is movable to. locked position in the .path of opening movement of the closure and is released to open the closure by raising the plate to release the latter for swinging to a closure-releasing position.

2. Discussion of the Prior Art.

US. Pat. No. 2,794,665 discloses-a door night latch which is in common use in homes, hotels, motels and thelike. This night latch has a striker plate hinged to akeeper plate which is secured to the door jamb.'The

striker plate is swingable between a door-engaging position and a door-releasing position relative to the keeper p'late.'When in its door-engaging position, the

. striker plate is located in the-path of opening movement of the door and is movable downwardly along the hinge axis to a locked position'wherein the striker plate is locked against swinging to its door-releasing position by interengagement of locking lugs on the striker and keeper plates to .lock the door against opening. The latch is released to open the door by first raising the striker plate to disengage the locking lugs and then swinging the plate to -its door-releasing position.

The existing latches of this kind suffer from one disadvantage which this inventionovercomes. The disadvantage referred to resides inthe fact that the latch can be opened from the outside by inserting a thin card or blade between the door and jamb below the striker plate and raising the plate to its. unlocked position by sliding the-card upwardly. The latch can be picked or unlocked in this way for the reason that in the locked position of the striker plate, its lower end extends below. the lower end of the keeperplate such that the striker plate may be engaged and raised to'unlocked position by inserting a card below the plate, as described.

SUMMARY OF THE INVENTION The present invention provides a pick-proof latch of the class described, that is, a latch whose striker plate cannot be raised to unlocked position by insertion ofa card between the door and jamb. To this end, the latch plates are so sized and pivotally connected that in the locking position of the striker plate, its lower end does not project below the keeper plate. In the disclosed latch embodiment, for example, the keeper plate projects below the striker plate in the locking position of the striker plate. Accordingly, when a card is inserted between the door and jamb and moved upwardly, the card will engage the lower end of the keeper plate rather than the striker plate and thus will be prevented from raising the striker plate to unlocked position. 7

According to another feature of the invention, the lower end of the keeper plate has an abutment or stop, such as an adjustable screw, to extend between the outer side of the keeper plate and the door in the event the gap between the keeper plate and door is wider than the keeper plate thickness. This abutment or screw prevents sliding a card upwardly between the .door and keeper plate into contact with the striker plate and thereby raising the latter to unlocked position. This disclosed latch is also reversible so that it may be installed on either a left-hand or right-hand opening door.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a present latch in unlatched or closure-releasing position;

FIG. 2 is a view looking in the direction of the arrows 2-2 in FIG. 1;

FIG. 3 illustrates the latch in latched position;

FIG. 4 is a view looking in the direction of the arrows 4-4 in FIG. 3; and

FIG. 5 is a section taken on line 5-5 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The closure or night latch 10 illustrated in the drawings has a keeper plate 12 and a striker plate 14 arranged edge to edge. The latch plates are joined along 7 their adjacent edges by hinge means 16 for swinging of the striker plate relative to the keeper plate on the hinge axis 18 and endwise movement of the striker plate .relative to the keeper plate along the axis. The keeper plate 12 is secured by screws 20 to the jamb 22 of an opening containing a hinged closure 24, such as a .door. The side of the keeper plate seating against the jamb is referred to as its rear side. The opposite side of the keeper plate is referred to as its front or outer side.

Hinge means 16 comprise a number, in this instance three, of generally cylindrical bearings 26 spaced along the inner edge of the keeper plate 12 and rotatably receiving pivot shafts 28 along the inner edge of the striker plate 14. P-ivot shafts 28 are formed by pinching openings 30 through the striker plate adjacent its edge so as to leave narrow shaft-like sections of the plate along the inner edges of the openings. The bearings 26 are formed by slotting the inner edge of the keeper plate to form tongues along the edge and then curling these tongues through the striker plate openings 30 and about the pivot shafts 28 into cylindrical bearing shapes which surround the shafts. The axial dimension of the bearings 26 is less than the corresponding'dimension of the striker plate openings 30 to provide the striker plate 14 with limited freedom of endwise movement relative to the keeper plate 12.

Hinge means 16 support the striker plate 14 for swinging relative to the keeper plate 12 between a closure-releasing position (FIGS. 1 and 2) and a closureengaging position (FIGS. 3-5). When in closurereleasing position, the striker' plate is located either generally coplanar with or rearwardly of the keeper plate such that the striker plate has no projection beyond the outer side of the keeper plate which would obstruct swinging of the closure 24' between open and closed position. The striker plate of the illustrated latch when in closure-releasing position is located at the rear ,side of the keeper plate, against the inner edge of the Keeper plate 12 and striker plate 14 have coacting latch means 32 for releasably locking the striker plate against swinging from its closure-engaging position to its closure-releasing position and thereby locking the closure 24 in closed position. Latch means 32 comprise slots 34 in the ends of the hinge bearings 26 for receiving the upper edges of the striker plate openings 30 when the striker plate occupies its closure engaging position. Latch means 32 comprise additional slots 36 in the bearing ends for receiving the upper edges of the striker plate openings when the striker plate occupies its closure releasing position to lock the striker plate from swinging from this position to its closure-engaging position. Latch means 32 are disengaged to permit swinging of the striker plate 14 between the closure engaging and releasing positions by raising the plate endwise to retract the upper edges of the plate openings 30 from the

hinge bearing slots

34 or 36, as the case may be.

It is now evident that the striker plate 14 has a locked closure-engaging position. and an unlocked or released closure-engaging position. In its locked closureengaging position, the striker plate is located in its closure-engaging position with the latch means 32 engaged to lock the plate against swinging to its closurereleasing position. In its unlocked or released closureengaging position, the striker plate is located in its closure-engaging position with the latch means disengaged to permit swinging of the plate to its closure-engaging position. The striker plate is movable endwise between these locked and released positions.

It is significant to note here that the illustrated latch is reversible end for end and the hinge bearings 26 are slotted at each end to permit installation of the latch on either right or left-hand opening closure or door structures. The striker plate 14, when in its unlocked or released closure-engaging position, is centered endwise relative to the keeper plate 12. The striker plate is movable in each endwise direction from this centered unlocked position to a locked closure-engaging position. In both the right and left-hand closure installations, the striker plate 14 is raised to disengage the latch means 32 and lowered to engage the latch means so that gravity acts to retain the latch means in engagement. At each end of the striker plate is a threaded hole 38 for receiving a stop screw 40. This screw is threaded in the lower hole 38 in both the right and left-hand installations and its head is dimensioned to engage the lower hinge bearing 26 in such a way as to prevent raising of the striker plate to its upper locked position.

As noted earlier, the present invention is concerned with latch improvements which render the latch immune to being picked or unlocked by means of a card inserted between the closure 24 and jamb 22. According to the invention, this is accomplished by arranging the striker plate 14 so that in its lower locked closure engaging position, its lower edge does not project below the lower edge of the keeper plate 12. In the disclosed latch, for example, the striker plate is made sufficiently shorter than the keeper plate that in each locking position ofthe striker plate, its lower edge is located a distance above the lower edge of the keeper plate. Under these conditions, assuming the keeper plate to be of sufficient thickness to virtually fill or bridge the gap between the jamb 22 and closure 24, a card 42 inserted into the gap below the latch, in the manner shown in FIG. 5, and slid upwardly through the gap will encounter the lower edge of the keeper plate rather than the striker plate. The keeper plate will thus prevent the striker plate from being raised to its unlocked position by the card to open the closure.

In some cases, the gap between the jamb 22 and closure 24 may be substantially wider than the thickness of the keeper plate 12. It would then be possible to slide the card 42 upwardly between the door and keeper plate into contact with the striker plate 14 and raise the latter to unlocked position to open the closure. According to a feature of the invention, this possibility is prevented by providing threaded holes 44 at the ends of the keeper plate for receiving a stop screw 46. This screw is inserted into the lower hole and adjusted to bridge the gap between the keeper plate and jamb at a position below the lower edge of the striker plate, at least in the unlocking position of the plate and, preferably, in the locking position of the plate, as shown. When thus adjusted, the screw provides an abutment which will prevent raising of the striker plate 14 with a card 42 even though a gap exists between the keeper plate and jamb.

What is claimed as new in support of Letters Patent l. A latch for a swinging closure such as a door, having a vertical edge which faces an upright jamb in closed position comprising:

a keeper plate and a striker plate arranged edge to edge, said keeper plate having a rear side for seating against said jamb and an opposite outer side,

hinge means pivotally connecting said plates along their adjacent edges for swinging of said striker plate relative to said keeper plate on the hinge axis and endwise movement of said striker plate relative to said keeper plate along the hinge axis,

means for securing said keeper plate to the door jamb with said rear side seating against the jamb and said hinge axis vertical, whereby said plates have edges which are lower edges and opposite edges which are upper edges when the latch is secured to the jamb,

said striker plate being swingable beyond said outer side of said keeper plate to a closure-engaging position relative to said keeper plate and toward said rear side of said keeper plate to a closure-releasing position relative to said keeper plate, and said striker plate when in said closure-engaging position being vertically movable along said axis between a lower striker plate locking position and an upper striker plate unlocking positions, coacting means on said plates which engage in said locking position to lock said striker plate against swinging to said closure-releasing position and disengage in said unlocking position to permit swinging of said striker plate to said closure-releasing position, and

an abutment member secured to and projecting beyond said outer side of said keeper plate at a position which is below the lower edge of said striker plate at a position which is below the lower edge of said striker plate at least when the latter plate is in said unlocking position to prevent raising of said striker plate to unlocking position and rotation of the striker plate to closure releasing position by insertion of an implement between said jamb and closure edge.

2. A latch according to claim 1 including:

said abutment member is located below the lower edge of said striker plate when the latter plate is in said locking position.

3. A-latch according to claim 3 wherein:

said abutment member comprises a screw threaded in said keeper plate for adjustment toward and away from said keeper plate.

4. A latch according to claim 1 wherein:

said latch is reversible for attachment to a jamb in an inverted position wherein said opposite plate edges are lowermost,

said striker plate when in said unlocking position is movable along said hinge axis from said striker plate unlocking position toward said opposite keeper plate edge to a second striker plate locking position,

additional coacting means on said plates which engage in said second locking position to lock said striker plate against swinging to said closurereleasing position, and

a second abutment member secured to and projecting beyond said outer side of said keeper plate at a position which is below said opposite striker plate edge when the latter plate is in said unlocking position with said latch in said inverted position.

5. A latch according to claim 4 wherein:

said second abutment member is located below said opposite striker plate edge when said striker plate is in said second locking position with said latch in inverted position.

6. A latch according to claim 5 including:

said second abutment member comprises a screw threaded in said keeper plate for adjustment toward and away from said keeper plate.

7. A latch according to claim 1 including:

a screw threaded in said striker plate and engagable with said keeper plate for selectively restraining said striker plate against endwise movement to locking position. i

Claims

1. A latch for a swinging closure such as a door, having a vertical edge which faces an upright jamb in closed position comprising: a keeper plate and a striker plate arranged edge to edge, said keeper plate having a rear side for seating against said jamb and an opposite outer side, hinge means pivotally connecting said plates along their adjacent edges for swinging of said striker plate relative to said keeper plate on the hinge axis and endwise movement of said striker plate relative to said keeper plate along the hinge axis, means for securing said keeper plate to the door jamb with said rear side seating against the jamb and said hinge axis vertical, whereby said plates have edges which are lower edges and opposite edges which are upper edges when the latch is secured to the jamb, said striker plate being swingable beyond said outer side of said keeper plate to a closure-engaging position relative to said keeper plate and toward said rear side of said keeper plate to a closure-releasing position relative to said keeper plate, and said striker plate when in said closure-engaging position being vertically movable along said axis between a lower striker plate locking position and an upper striker plate unlocking positions, coacting means on said plates which engage in said locking position to lock said striker plate against swinging to said closure-releasing position and disengage in said unlocking position to permit swinging of said striker plate to said closure-releasing position, and an abutment member secured to and projecting beyond said outer side of said keeper plate at a position which is below the lower edge of said striker plate at a position which is below the lower edge of said striker plate at least when the latter plate is in said unlocking position to prevent raising of said striker plate to unlocking position and rotation of the striker plate to closure releasing position by insertion of an implement between said jamb and closure edge.

2. A latch according to claim 1 including: said abutment member is located below the lower edge of said striker plate when the latter plate is in said locking position.

3. A latch according to claim 3 wherein: said abutment member comprises a screw threaded in said keeper plate for adjustment toward and away from said keeper plate.

4. A latch according to claim 1 wherein: said latch is reversible for attachment to a jamb in an inverted position wherein said opposite plate edges are lowermost, said striker plate when in said unlocking position is movable along said hinge axis from said striker plate unlocking position toward said opposite keeper plate edge to a second striker plate locking position, additional coacting means on said plates which engage in said second locking position to lock said striker plate against swinging to said closure-releasing position, and a second abutment member secured to and projecting beyond said outer side of said keeper plate at a position which is below said opposite striker plate edge when the latter plate is in said unlocking position with said latch in said inverted position.

5. A latch according to claim 4 wherein: said second abutment member is located below said opposite striker plate edge when said striker plate is in said second locking position with said latch in inverted position.

6. A latch according to claim 5 iNcluding: said second abutment member comprises a screw threaded in said keeper plate for adjustment toward and away from said keeper plate.

7. A latch according to claim 1 including: a screw threaded in said striker plate and engagable with said keeper plate for selectively restraining said striker plate against endwise movement to locking position.