US3897966A

US3897966A - Chain door latch assembly

Info

Publication number: US3897966A
Application number: US483545A
Authority: US
Inventors: Sr Harry C Draughon
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-06-27
Filing date: 1974-06-27
Publication date: 1975-08-05
Anticipated expiration: 1992-08-05

Abstract

A combination door latch and safety chain assembly utilizes a single chain which functions as both a safety chain and latch. The chain is formed of a plurality of links serially interconnected for flexible movement by pivot means which restrict flexing of the chain to one plane. The pivot pins lie in a second plane perpendicular to said one plane. The chain is extendable from a barrel mounted to the door for engagement with a receiver on the door jamb and is manually rotatable for orientation with respect to the plane of the door. When the bolt disc on the end of the chain is engaged with the receiver and the chain is oriented with the plane of the pins substantially parallel to the door, the chain is flexible to door movement to function as a safety chain. And when the chain is oriented with the common plane of the pins substantially perpendicular to the door, the chain is inflexible so as to function as a lock or latch. The end of the chain opposite the bolt disc is secured to a spring inside the barrel so that the chain automatically retracts when the chain is disengaged from the receiver, or when the door is closed in the safety chain mode.

Description

United States Patent n9} Draughon, Sr.

[lll 3,897,966

Aug. 5, 1975 l CHAIN DOOR LATCH ASSEMBLY [76] Inventor: Harry C. Draughon, Sr.. 4371 Glenwood Rd.. Apt. F Decatur. Ga 30032 22 Filed: June 27,1974

21 Appl. N0.:483,545

3.797.868 3/[974 Carey 292/262 Primary E.\'armner-Richard E. Moore Attorney. Agent, or FirnzLowe, King & Price [57] ABSTRACT A combination door latch and safety chain assembly 3 we 0 4s utilizes a single chain which functions as both a safety chain and latch. The chain is formed of a plurality of links serially interconnected for flexible movement by pivot means which restrict flexing of the chain to one plane. The pivot pins lie in a second plane perpendicular to said one plane. The chain is extendable from a barrel mounted to the door for engagement with a receivcr on the door jamb and is manually rotatable for orientation with respect to the plane of the door. When the bolt disc on the end of the chain is engaged with the receiver and the chain is oriented with the plane of the pins substantially parallel to the door, the chain is flexible to door movement to function as a safety chain. And when the chain is oriented with the common plane of the pins substantially perpendicular to the door. the chain is inflexible so as to function as a lock or latch. The end of the chain opposite the bolt disc is secured to a spring inside the barrel so that the chain automatically retracts when the chain is disengaged from the receiver. or when the door is closed in the safety chain mode.

12 Claims. 6 Drawing Figures PATENTEU AUG 5 I975 FIG. 2

PATENIEB AUG 5l975 3.897, 965

SHEET 2 CH LOCK PO ON FIGS POSITION RELEASE SAFETY CHAIN POSITION CHAIN DOOR LATCH ASSEMBLY FIELD OF THE INVENTION The present invention relates generally to a door latching assembly and more particularly to a door latching assembly which functions as both a latch and safety chain.

DESCRIPTION OF THE PRIOR ART It is often desirable to provide a latch to supplement a door lock, especially in areas having a high crime rate. In addition, in order to permit a person within a dwelling to ascertain who desires admission before permitting him to enter, and to allow the door to be left ajar when desired for the purpose of ventilation, it is useful to include a means for permitting the door to be opened only partially.

In the most prevalent type of arrangement used heretofore, a sliding latch is secured to the door opposite a latch receiver mounted in the jamb. When the door is closed, the latch is engageable with the receiver to bridge the gap between the door and jamb thereby preventing the door from being opened. Generally, a separate chain is also provided which is connectable between the door and another receiver on the jamb to permit the door to be opened to the extent of the length of the chain. The door can be latched completely closed with the latch, or it can be allowed to be opened partially by securing the free end of the chain to the receiver before disengaging the latch. While generally satisfactory, this arrangement requires separate parts and separate manual operations for selectively latching and chaining the door. In addition, when the free end of the chain is connected to the receiver on the jamb, the chain dangles between the mechanism and receiver creating an unsightly appearance.

In a second type of mechanism of the prior art where an attempt has been made to combine the latch and chain functions, one end ofa chain is fastened to a bar which slides along the inside of a barrel to provide a retractable chain. When a locking portion of the bar is manually lodged in a slot formed at the end of the barrel opposite the receiver, the chain is held fast fully retracted into the barrel. With the free end of the chain secured to the receiver, the chain tautly bridges the gap between the door and jamb tending to prevent opening the door. On the other hand, when the free end of the chain is secured to the receiver with the bar lodged in a slot formed at the end of the barrel adjacent the receiver, the chain hangs freely and the door may be opened to the extent of the length of the chain. This concept was proposed long ago in US. Pat. No. 2l7,5 65 issued to T. P. White. The product, insofar as I am aware, was never produced. It could have been generally satisfactory. However, in the latched position, there was no positive means to resist opening the door since the chain could flex in the direction of the movement. Also, the appearance of the chain dangling between the door and jamb is unsightly and is an attractive nuisance for children. An annoying clanking sound is created as the dangling chain strikes against the door in such an uncontrolled arrangement.

OBJECTS OF THE INVENTION Accordingly, it is one object of the present invention to provide a new and improved door latching assembly.

It is another object of the present invention to provide a new and improved door latching assembly capable of selectively latching the door closed, or permit ting the door to be opened partially.

It is yet another object of the present invention to provide a new and improved door latching assembly utilizing a single chain to both latch the door closed and permit the door to be opened partially.

It is another object of the present invention to provide a new and improved door latching assembly which is convertible for operation between that of a latch and of a safety chain.

It is another object of the present invention to provide a new and improved door latching assembly having a safety chain that automatically retracts out of sight when the door is closed or the chain is not used.

BRIEF DESCRIPTION OF THE INVENTION A combination door latch and safety chain assembly uses a chain that is flexible in only one plane. Preferably housed in a barrel inside the door, the chain is formed of a plurality of links interconnected by pivot pins. The chain is supported along the axis of the barrel by a chain guide and, with a selector knob or lever, is manually rotatable to orient the common plane of the pins to be either substantially parallel or perpendicular to the door.

The chain guide contains a pair of fingers between which the chain is held. One end of the chain is secured to the interior of the barrel with a spring. An oblong bolt disc, connected to the other end of the chain is adapted to mate with a slot in a receiver on the door jamb. By rotating the bolt disc inside the slot by means of the selector knob, the bolt disc becomes locked in the receiver. This is true for either chain lock" or safety chain" operation.

More specifically, the assembly has three modes of operation, i.e., chain lock, safety chain and release. When the door is closed, the selector knob is manually thrust toward the receiver to cause the bolt disc to mate with a slot in the receiver and then manually flicked up or down to lock the bolt disc and orient the chain to either chain lock or safety chain the door. In the safety chain position, the chain is oriented with the common plane of the pivot pins parallel to the door and the chain, due to the pivoting action of the links, is flexible to movement of the door thereby permitting the door to be opened to the extent of the length of the chain. In the chain lock position, the chain is oriented with the common plane of the pivot pins perpendicular to the door and the chain is inflexible to movement of the door to positively prevent even a partial opening thereof. With the selector knob in the release" position, the bolt disc, in alignment with the slot on the receiver, is free to engage or disengage the receiver. When disengaged from the receiver or when the door is closed in the safety chain mode, the chain retracts into the barrel under the force of the spring.

Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, where I have shown and described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by me of carrying out my invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature. and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a top sectional view of the apparatus of the present invention with the door closed and the chain oriented in the chain lock mode;

FIG. 2 is a top sectional view of the apparatus with the chain oriented in the safety chain mode and the door opened to the extent of the length of the chain;

FIGS. 3a and 3b are views of the receiver taken along the line 33 in FIG. I showing the bolt disc in the chain lock and safety chain modes, respectively;

FIG. 4 is a front view of the barrel with a portion removed to show the interior thereof; and

FIG. 5 is a sectional view taken along the line S5 in FIG. 1 showing the selector knob and the three posi tions thereof.

DETAILED DESCRIPTION OF THE DRAWING With reference to FIG. I, a chain door bolt assembly is mounted inside a door 12 adjacent a door jamb I4. The door 12 is closed against a door stop moulding l3 and latched to a receiver 15 with the assembly 10. The assembly 10 comprises a barrel l6 enclosing a chain 18 and a chain guide, generally designated by the reference numeral 20. The chain guide 20 is fork-like, being formed of two fingers 22 and 24 (FIG. 2) secured to a drum 26. The chain I8 is held captive between the fingers to lie along the axis 25 of the barrel I6.

A selector knob or lever 28 having a neck 29 and a gripping portion 30 is secured to the drum 26 through a T-shaped slot 31 in the barrel 16. The drum 26 is freely moveable inside the barrel I6 limited by the ac tion of the neck 29 of the selector knob 28 against the rim forming the T'shaped slot 3].

One end of the chain is connected to an anchor 32 which is disc-shaped with openings to allow sliding along the

fingers

22 and 24 of the chain guide 20. As the chain is withdrawn from the barrel, the anchor slides along the axis 25 (see FIG. I) of the barrel 16 until the limit of movement is reached, as shown in FIG. 2.

An end portion 38 of the barrel I6, mounted to the edge of the door 12 adjacent the receiver I5, is secured to the barrel by the threaded coupling 42. The receiver I5 is anchored to the jamb 14 with screws 36 and, similarly, the end portion 38 may be anchored to the door with screws (not shown). It is best to provide all screws with tamper-proof heads (see FIGS. 3a, 3b) to prevent unauthorized entry by removal of the latch. As a further safety feature, the head of the center screw 36 on the receiver 15 is totally blocked from access by the bolt disc 33 in the safety chain position of FIG. 2.

A spring 37 inside the barrel l6 resiliently separates the anchor 32 from the end portion 38. When the chain 18 is withdrawn from the barrel 16 during opening of the door in the chain lock mode, the spring 37 is compressed by the anchor 32. The limit of movement occurs when the spring 37 bottoms out (FIG. 2). A force tending to retract the chain back into the barrel is exerted on the door, thus automatically urging the door closed at all times in this mode. To hold the door open for ventilation, any appropriate stop may be placed in the door in the well known manner.

To effect the attachment of the chain 18 to the reeeiver 15, the receiver 15 contains an oblong slot 44 for receiving the bolt disc 33. The bolt 33 is oblong to match and mate with the slot 44 when the two parts are aligned.

The slot 44 is formed of an outer portion having a first width W, (FIG. 2) corresponding to the smaller dimension D of the bolt disc 33 (FIG. 3a) and an inner portion having a second width W corresponding to the larger dimension D of the bolt disc 33. When the bolt disc 33 is mated with the slot 44 and rotated either clockwise or counterclockwise for safety chain or chain lock operation, the bolt disc 33 becomes lockingly engaged in the receiver, as shown in FIGS. 3a and 3b.

Referring to FIG. 5, the selector knob 28 is secured to the drum 26 by means of a bolt 52 which is screwed down into a tapped bore 54 in the drum 26. The knob 28 is seated against a chamfered portion 56 of the drum 26 and is held to the bolt 52 with a set screw 58 inserted through the neck 29 of the knob.

The chain 18 is formed of a plurality of links 46 serially interconnected to each other with pivot pins 48 (see FIGS. 2 and 4). Each link 46 is formed ofa plurality of leaves jointed together in juxtaposition by the pivot pins 48 (see FIGS. 3a and 4). Preferably, each link consists of four inner leaves and five outer leaves, each leaf having a thickness of 0.040 inch, but the particular number of leaves or thickness thereof is not crit ical. For example, another suitable structure would be five inner and six outer leaves of 0.031 inch material. The number of links 46 on the chain 18 corresponds to the distance from the end portion 38 of the barrel 16 to the drum 26 when the chain is retracted. The disc 33 fits in the end portion and the anchor 32 abuts the drum 26 when the knob 28 is moved to any position on the cross piece of T'shaped slot 31 (see FIG. I).

The pivot pins 48 lie in a common plane P and the chain is flexible only in a plane normal to the common plane by the pivoting action of the links. In FIG. I, the chain 18 is oriented with the common plane of the pivot pins 48 perpendicular to the vertical axis of the door 12 with the bolt disc 33 engaged with the receiver 15. It is apparent that the chain, oriented as shown, is not flexible to door movement and prevents in a positive manner the door 12 from opening even partially. On the other hand, as shown in FIG. 2, when the chain is oriented with the common plane P of the pivot pins parallel to the door, the chain is flexible to door move ment (in the plane of the paper, FIG. 2) and the door can be opened to the extent of the length of the chain when fully retracted from the barrel 16.

The selector knob 28 can be placed in any of three positions, ie, chain lock, release and safety chain. In FIG. 5, the slot 31 is T-shaped. The cross piece of the T includes an upper portion 60 for chain lock, a lower portion 62 for safety chain and a middle portion 64 for release. The release portion 64 is displaced along the axis of the barrel from the

positions

60 and 62. When the selector knob 28 is in the release position 64, the chain 18 is fully retracted into the barrel under the force of the spring 37 and the bolt disc 33 is seated in the end portion 38.

In the release mode, the chain 18 is oriented obliquely (at 45) to the door and the bolt disc 33 is aligned with the slot 44 in the receiver 15 as shown in FIG. 4.

When the selector knob 28 is manually displaced toward the left for chain lock or safety chain operation, the bolt disc 33 enters the slot 44 in the receiver and just abuts the inside surface 66 thereof as the selector knob strikes the end 68 of the slot 31. When the selector knob 28 is then flicked upwardly to the chain lock position, the drum 26, chain guard 20, chain 18 and bolt disc 33 rotate approximately 45 to lock the bolt disc in the inner portion W of the receiver slot 44, as best shown in FIG. 3a. In the chain lock mode, the common plane P of the pins 48 of the chain 18 is substantially perpendicular to the door and the chain, rigid to door movement, and thereby positively holds and prevents the door from opening even partially.

When the selector knob 28 is flicked downwardly to the safety chain position, the chain 18 and bolt disc 33 are oriented as shown in FIG. 3b. The bolt disc is now again locked within inner portion W of the slot 44 of the receiver 15 but ninety degrees from the original locked position. The common plane P of the pins 48 is oriented parallel to the door as a consequence. Thus in safety chain operation, the chain 18 is flexible to door movement. As the door is opened, the first links drawn from the barrel 16 are pulled contiguously along slot 44 providing enough clearance between the door 12 and receiver for the thickness of the chain. As the door 12 is opened further, the chain 18 continues to be drawn outwardly from the barrel 16 against the force of the spring 37. Then when the door is subsequently closed, the action of the spring 27 against the anchor 32 causes the chain 18 to automatically retract into the barrel 16.

To release the bolt disc 33 from the receiver 15, the selector knob 28 is manually placed in the release position 64, and the bolt disc 33, now in alignment with the slot 44, disengages from the receiver to seat into the end portion 38 under the force of the spring 37.

Thus, the assembly 10 has three modes of operation, i.e., a chain lock mode with the selector knob 28 positioned in the upper portion 60 of the T-shaped slot 31 to secure the door completely closed, a safety chain mode with the selector knob positioned in the lower portion 62 permitting the door to be opened partially and a release mode with the knob positioned in the middle portion 64. The user can conveniently choose between the three modes of operation with a flick of the selector knob. Controlling all three modes ofoperation with one easy to manipulate control is an important aspect of the present invention.

In this disclosure, there is shown and described only the preferred embodiment of the invention, but as aforementioned it is understood that the invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein. For example, to eliminate the requirement of installing the assembly inside the door, the assembly can be mounted to the outer surface of the door inside the dwelling with the receiver mounted to the jamb adjacent the assembly. The chain 18 may have any desired number of leaves and may be any suitable gauge thickness to give the required strength to hold the door against an attempt of forced entry when the chain 18 is in the locked mode.

To finally review the operation, when the door is to be locked, the knob 28 is moved in the T-slot 31 (to the left in FIG. 4) against the force of the spring 37, and then upwardly to the chain lock position (FIG. 5). This action first moves the disc 33 into the receiver 15, and second, locks it in position (FIG. 3a). If it is desired to open the door slightly (to view a caller, for example), the knob 30 is held forward against edge 68 of T-slot 31 to resist the action of spring 37 (to keep the disc 33 in the receiver 15) and then rapidly moved downwardly through ninety degrees directly to the safety chain position. Now the chain is orientated so as to allow flexing, and the door may be opened. To uncouple the latch and allow full opening of the door, the door is first closed and the knob is flicked upwardly. The knob stops upward travel after 45 at the release position, whereby upon the spring automatically retracts the chain and disconnects the disc 33. The door can now be opened.

In summary, there is provided a new and improved combination door latch and safety chain. Depending on the orientation of the connector pins 48 between links 46 of the chain 18 with respect to the door, it is either held fast in the closed position (FIG. 1) or allowed to open partially (FIG, 2). The latch positively holds the door closed by the single chain 18, that also performs the chaining function. The T-shaped slot 31 and single control lever 28 gives easy, fool-proof operation. The chain 18 is spring-loaded and hidden within the barrel 16 except when the door is pulled open slightly, such as when viewing a caller. Even when so extended, the chain 18 is controlled and the spring 37 tends to pull the door to the closed position.

What is claimed is: l. A combination door latch and safety chain assembly comprising:

chain means having a plurality of links serially interconnected with pivot means so as to be flexible in only one plane, said one plane being perpendicular to a second plane passing through said pivot means;

support means for positioning said chain means with respect to a door; receiver means securable to a door jamb to engage said chain means, said chain means being extendable between said door and said jamb; and

selector means for selectively orienting said chain means with respect to said door, whereby said chain means when engaged with said receiver means is flexible in said one plane to allow movement of said door, said movement being when said chain is oriented with the second plane of said pivot means thereof aligned substantially parallel to said door, and said chain means being inflexible in said one plane to prevent movement of said door when said chain is oriented with the second plane of said pivot means substantially perpendicular to said door.

2. The assembly of claim 1 wherein said support means includes a barrel for housing said chain means, said chain means being restricted to move along the longitudinal axis of said barrel and extendable therefrom to engage said receiver means.

3. The assembly of claim 2 wherein said support means further includes spring means inside said barrel for biasing said chain means to retract into said barrel along the axis thereof.

4. The assembly of claim 2 wherein said selector means includes chain guide means located inside said barrel and rotatable for orienting said chain with respect to said door, and means external to said barrel for rotating said chain guide means.

5. The assembly of claim 4 wherein said chain guide means includes a pair of fingers embracing said chain means and rotatable about the longitudinal axis of said barrel; and said rotating means includes a selector knob extending through a slot in said barrel and connected to said chain guide.

6. The assembly of claim 5 including a drum freely mounted inside said barrel, said fingers secured to said drum and said selector knob fastened to said drum.

7. The assembly of claim 1 including a bolt disc secured to one end of said chain means, and said receiver means containing a slot for receiving said bolt disc.

8. A combination door latch and safety chain assembly comprising:

a chain having pivot means making the same flexible in only one plane, said chain positioned along the axis of a barrel, said barrel being mountable to a door;

a receiver mountable to a door jamb to engage one end of said chain; and

a chain guide located inside said barrel for orienting the rotational position of said chain along said axis. said chain guide having:

a first rotational position for orienting said chain to be flexible to opening movement of said door;

a second rotational position for orienting said chain to be inflexible to opening movement of said door; and

a third rotational position for selectively engaging and disengaging said one end of said chain from said receiver.

9. The assembly of claim 8 including spring means for automatically retracting said chain into said barrel.

10. The assembly of claim 9 including a selector knob accessible externally to said barrel and secured to said chain guide through a slot in said barrel.

1 l. The assembly of claim 8 including a bolt disc secured to said one end of said chain, and wherein said receiver contains a slot for receiving said bolt disc.

12. The assembly of claim ll wherein said bolt disc is oblong having a first diameter and a second diameter, and said receiver slot includes a first portion for receiv ing said bolt disc and a second portion for locking said bolt disc to said receiver.

Claims

1. A combination door latch and safety chain assembly comprising: chain means having a plurality of links serially interconnected with pivot means so as to be flexible in only one plane, said one plane being perpendicular to a second plane passing through said pivot means; support means for positioning said chain means with respect to a door; receiver means securable to a door jamb to engage said chain means, said chain means being extendable between said door and said jamb; and selector means for selectively orienting said chain means with respect to said door, whereby said chain means when engaged with said receiver means is flexible in said one plane to allow movement of said door, said movement being when said chain is oriented with the second plane of said pivot means thereof aligned substantially parallel to said door, and said chain means being inflexible in said one plane to prevent movement of said door when said chain is oriented with the second plane of said pivot means substantially perpendicular to said door.

8. A combination door latch and safety chain assembly comprising: a chain having pivot means making the same flexible in only one plane, said chain positioned along the axis of a barrel, said barrel being mountable to a door; a receiver mountable to a door jamb to engage one end of said chain; and a chain guide located inside said barrel for orienting the rotational position of said chain along said axis, said chain guide having: a first rotational position for orienting said chain to be flexible to opening movement of said door; a second rotational position for orienting said chain to be inflexible to opening movement of said door; and a third rotational position for selectively engaging and disengaging said one end of said chain from said receiver.

11. The assembly of claim 8 including a bolt disc secured to said one end of said chain, and wherein said receiver contains a slot for receiving said bolt disc.

12. The assembly of claim 11 wherein said bolt disC is oblong having a first diameter and a second diameter, and said receiver slot includes a first portion for receiving said bolt disc and a second portion for locking said bolt disc to said receiver.