US2966053A - Safety door chain - Google Patents

Description

Dec. 27, 1960 A. E. MINTZ 2,966,053

' SAFETY DOOR CHAIN Filed Feb. 27, 1958 2 Sheets-Sheet 1 ALB ERTEM/NTZ 31 BY ift; W

Dec. 27, 1960 A. E. MINTZ SAFETY DOOR CHAIN Filed Feb. 27, 1958 2 Sheets-Sheet 2 INVENTOR. ALBERTE. M/wz United States Patent O SAFETY DOOR CHAIN Albert E. Mintz, 61-64 Saunders St., Rego Park 74, N.

Filed Feb. 27, 1958, Ser. No. 718,035

7 Claims. (CI. 70-93) This invention relates to safety chains for doors and more particularly to safety chains which may be locked and unlocked from the outside by authorized persons as well as used in their normal manner by persons on the inside.

Safety chains are widely used to permit partial opening of the door for ventilation or to permit a person on the inside to observe and converse with persons on the outside and yet keep the person on the outside from forcing his way into the house or room. Safety chains are also used as auxiliary night latches and provide additional security to a wife whose husband works late at night, is away on an overnight business trip or is out visiting an occasional sick friend. These chains require someone on the inside to lock and unlock them.

A problem is presented, however, when the husband returns, since he must awaken the wife to undo the safety chain to let him in. This can be of considerable annoyance to the wife as well as possible embarrassment to the husband because of the lateness of the hour or other circumstances.

The safety chain comprising the present invention is adapted to be fastened to the door and door frame to permit partial opening of the door for use in the conventional manner. Additional means is provided for attaching and detaching the chain by an authorized person from the outside. One end of the chain is connected to a plug which may be inserted into a casing mounted on the door frame and snapped into locking position. The other end of the chain is in removable engagement with a standard chain bracket mounted on the door. A key may be inserted in a keyhole at the upper end of the plug to release it from its casing to free the chain and permit the door to be opened. The releasing of the plug may be accomplished from the exterior by opening the door within the limits prescribed by the chain and inserting the key in the keyhole. Likewise, upon leaving the house, the plug may be readily inserted into the casing, snapped into locking position and the door then shut and further locked with existing locks as desired or left open with the opening of the door again restricted by the chain. This safety chain does not require modification or replacement of existing door locks or complicated installation. The average housewife can mount it for use in about five minutes with a screwdriver and a few wood screws.

It is therefore an object of this invention to provide for a safety door chain which may be locked and unlocked by persons inside the door and authorized persons on the outside.

Another object is the provision of a key actuated lock for removing one end of a safety door chain.

Another object is the provision of a safety door chain which may be unlocked from the outside by opening the door to the limit permitted by the chain and detaching one end of the chain by operating a key actuated lock which connects the chain to the door or door frame.

Another object is the provision of a cylinder type lock with key actuated tumblers for use in locking and unlock- 2,966,053 Patented Dec. 27, 1960 Figure 3 is a plan view of the plug part of the lock,

Figure 4 is a front elevation of a modified form of safety chain lock,

Figure 5 is a similar view but with the lock shown rotated counterclockwise ninety degrees,

Figure 6 is a partial section on the line 6-6 of Figure 4 with parts broken away, and

Figure 7 is a vertical section on the line 77 of Figure 6.

Referring to Figure 1, there is shown a fragmentary portion of a door 10 and door-frame 11. The door has a knob 12, and the usual door locks which are not shown in the drawing.

In the preferred embodiment of the invention a safety chain 13 is shown attached at one end 14 to the slide part 15 which engages a standard chain bracket 16 secured to the door 10. The length of the chain is such that with the other end 17 aflixed to the door frame 11, the slide a part 15 cannot be released from the bracket until the door is substantially fully closed.

A lock 20 is shown for illustrative purposes as mounted on the door frame 11. It consists of a rectangular latch casing 21, and a detachable plug 22 for insertion therein, the plug being attached to end 17 of the chain. As shown in Figure 3 the casing 21 has an oblong opening 23 extending through it to receive plug 22. A hollow cylindrical boss 24 projects rearwardly into an aperture in the central elevated part 25 of a rectangular mounting plate 26, shown in Figure 1 as secured by screws 27 to door frame 11. The outer end of boss 24 is shouldered and secured in place by upsetting it within an opening in a retaining plate 28 and bonded or welded to prevent separation thereform. A pin 29 projects rearwardly from casing 21 and into an aligned hole 18 in part 25 to prevent the casing from pivota-lly moving about the axis of boss 24.

In assembly, plate 28 bears against the inner surface of the elevated part 25 of plate 26 with the opposing rear Wall of casing 21 contiguous the outer wall of said part. Casing 21 is thus rigidly supported on the door frame with opening 23 vertically disposed for a purpose which will presently appear.

The detachable plug 22 of the lock 29 is relatively long since it contains a conventional cylinder lock 30 with key actuated tumblers as shown in Figure 6. Although this view partly in section, of plug 22 illustrates its use in a reversed position with respect to the position shown in Figure 2 it is identical structurally in both instances.

As viewed from its end plug 22 is of oblong configuration, as shown in Figure 3, and is adapted to fit snugly Within the oblong opening 23 of casing 21. A lug 31 is integrally formed at one end of plug 22 and is apertured to receive the end link 17 of the chain 13. A stop pin 32 projects from one side of lug 31 sufficiently to engage the casing 21 and limit the movement of the plug inwardly. Movement in an outward or opposite direction is normally opposed by a latch 33 mounted transversely for reciprocal movement across the major width of plug 22, and so as to extend within the hollow boss 24 and prevent unauthorized withdrawal of plug 22.

Latch 33 is chamfered as at 34 so as to engage a similar inclined surface 35 formed at one end of opening 23 to depress the latch as the lug is inserted into the opening. As shown in Figure 6 spring 36 urges latch 33 outwardly, the latter being formed with a square shank 37 to prevent it from rotating in a correspondingly shaped opening 38 in plug 22. At its outer end the latch is cylindrical to thus provide a shoulder, indicated in dotted .lines in Figure 6, serving to limit its movement outwardly under the urging of spring 36.

The cylinder part 40 of lock 30 is provided at its inner end with a spindle 41 which is offset from the axis of part 40 so as to lie in a plane eccentric thereto. Spindle 41 extends into a recess 42 in latch 33 and engages a wall 43 thereof. Suificient clearance is provided between the spindle and an opposite wall of the recess to allow the latch to snap into the locked position shown in the drawings when plug 22 is pushed into the opening 23.

When the key 44 is inserted in the keyhole at the outer end of plug 22 and the cooperating tumblers are thereby brought into proper alignment in the conventional manner of locks of this character, a rotary movement of the key in either direction will rotate. cylinder 40 and cause its spindle 41 to impinge wall 43 and retract the latch. Then after pushing downwardly a short distance with the key held turned, the latch will be free of casing 21. and the key then may be Withdrawn. Plug 22 may then be pulled completely out of casing 21 by grasping the adjacent end of chain 13, and the door can be fully opened.

It. will now be apparent that the releasing of plug 22 may beeasily accomplished from the exterior by opening the door within the limits prescribed by the chain, and

then inserting the proper key in the conveniently located keyhole at the upper end of plug 22. Likewise, upon leaving the house, plug 22 may be readily inserted from beneath the casing and snapped into a locking position so that the opening of the door will again be restricted by the chain.

Referring to the modification shown in Figures 4, 5, 6 and 7, the arrangement shown is such that plug 22 may be conveniently inserted at the top of casing 21 with lug 31 uppermost. The construction in this modified form 'ofthe invention differs from that shown in the other figures by the provision of an arcuate slot 45 cut through elevated part 25 of plate 26 for. the reception of the pin 29. Casing 21 may thus swing about the axis of boss 24 through an angle of 90 degrees from the position shown in Figure 4 to that of Figure 5, the engagement of the pin with opposite ends of the slot defining such positions.

Since the door, if shown, would beto the right of Figure just as it is in Figure 1, the end of plug 22 into which the key 44 is to be inserted to free chain 13, will also be more easily available from the exterior of the door, the position of the key at that time being shown in dotted lines in Figure 5.

It will be understood that the invention is not to be considered as limited to the use. of a slide and bracket at the other end of thechain since the end 14 of the chain could be secured to the door in a fixed position if desired. The use of the. slide and bracket, however, provides greater convenience for the householder by making it possible to release that end of the chain from the interior in a conventional manner without necessitating the use of a key at this time. Also, if desired the casing could be secured instead to the door with the other end of the chain fastened to the door frame.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is notlimited, thereto as many variations will be readily'apparent to those skilled in the art and the I claim:

1. A safety chain and lock for loosely connecting a door with the adjacent door frame to limit movement of said door and which may be disconnected from the side of the door and frame opposite to the side to which said chain and lock are mounted, said safety chain and lock com-prising a chain removably fastened to said door, a latch casing adapted to be secured to said door frame and having an opening therein, said opening having an axis parallel to the plane of said door frame, a plug for insertion in said casing opening, said plug being con nected to one end of said chain and having a keyhole therein, a spring-responsive latch mounted for reciprocal movement transversely in said plug, said casing and said latch being adapted to cooperate so that said plug can be snapped into locking engagement within said casing, a cylinderlock carried by said plug including a rotatable cylinder and key-actuated tumblers, a spindle projecting from the inner end of said cylinder and eccentric to the axis thereof, said spindle being adapted to retract said latch when said cylinder is rotated by a key in said keyhole to thereby unlock the plug to free the plug connected end of the chain from said door frame.

2. A safety chain and lock for loosely connecting a door with the adjacent door frame comprising a chain fastened to the inside of said door, a latch casing for attachment to said door frame and having an opening therein, a plug for insertion in said casing opening, said plug being connected to one end of said chainand having a keyhole, a spring-responsive latch mounted for reciprocal movement transversely in said plug, said casing and said latch being adapted to cooperate sothat said plug. can be snapped into locking engagement with said casing, a cylinder lock carried by said plug including a rotatable cylinder and key-actuated tumblers, a spindle projecting from the inner end of said cylinder eccentric to the axis thereof and adapted to retract said latch when said cylinder is actuated by a key in said keyhole, and unlock. the plug to free said one end of said chain, said casing having a boss projecting rearwardly therefrom, a plate to which said boss is pivotally secured constituting a bracket for operatively supporting said casing, means for limiting the rotary movement of said casing in each direction, whereby the plug may be inserted in the top of the casing when its opening is vertically aligned and a key may be inserted in the keyhole of the plug when said opening is horizontally aligned, said chain being sufliciently long to permit opening of said door wide enough to permit insertion and withdrawal of said plug from said casing by a person outside the door. 7

3. A safety door chain for mounting on one side of a door and a wall mounted lock, said lock comprising two separable parts, one of said parts being a wall mountable casing, said casing'having an opening therein whose axisis parallel to the wall upon which said casing is mounted, the other of said parts comprising a plug for. insertion in saidpcasing, opening, a'spring-responsive latch mounted for reciprocal movement'transversely in said plug, to provide locking engagement with said casing, means on said casing to receive said latch to prevent withdrawal of said plug, a cylinder" lock carried by'the plug. including a rotatable; cylinder and key-actuated tumblers, a spindle projecting from the innerend of the cylinder of said lock eccentric to the axis about which it rotates and adapted to retract said latch from its locking position when said cylinder is rotated by a key whereby said casing and plug may be unlocked and separated from each other, .saidpluggbeing connected to said door by said chain of such length as to permit insertion of said key into said lock from the other side of said door.

.4. A safety door chain comprising a chain with releasable means for attachment to the inside. of a door, a locking plug connected thereto, a casing with means forattachment to a door frame, said. casing having an opening therein with an axis parallel to the plane of said door frame for receiving said plug, said plug having latching means thereon for engagement with and receivable by said casing to prevent withdrawal of said plug, and means insertable into said plug for releasing said latching means to permit withdrawal of said plug, said chain being of such length as to permit the door to be partially opened to permit insertion of said means from outside said door when said door, chain, plug and easing are connected.

5. A safety door chain as in claim 4, said casing attachment means having an opening therein communicating with and at right angle to said casing opening, said latching means being spring urged into said attachment means opening when said plug is inserted into said casing opening.

6. A safety door chain as in claim 4, said plug latching means comprising a latch, an opening in said plug receiving said latch, spring means continually urging said latch outwardly, retaining means in said casing opening to receive said latch to prevent withdrawal of said plug from said casing, a key actuated rotatable cylinder in said plug, said cylinder having means thereon engageable with said latch to remove said latch from engagement with said casing retaining means.

7. A safety door chain as in claim 4, said casing attachment means comprising a mounting plate, said casing being pivotally mounted on said plate, a substantially arcuate slot in said plate, a pin on said casing received by said slot, said pin and slot thereby limiting pivotal movement of said casing.

References Cited in the file of this patent UNITED STATES PATENTS 1,136,357 Newman Apr. 20, 1915 2,002,260 Curl May 21, 1935 2,458,046 Audet Jan. 4, 1949 2,696,100 Nehls Dec. 7, 1954 FOREIGN PATENTS 6,448 Great Britain Mar. 15, 1912 11,532 Denmark Nov. 17, 1908 321,984 Italy Oct. 23, 1934 333,931 Germany Mar. 5, 1921

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