Title:
Backset extension unit for door locks
United States Patent 2299181


Abstract:
This invention relates to an extension unit whereby the backset of a lock unit when installed in a door may be materially increased, the present application being a continuation in part of my co-pending application Serial Number 277,768, filed June 7, 1939, now Patent No. 2,250,036, dated July...



Inventors:
Schlage, Walter R.
Application Number:
US35403440A
Publication Date:
10/20/1942
Filing Date:
08/24/1940
Assignee:
SCHLAGE LOCK CO
Primary Class:
Other Classes:
70/DIG.3, 292/1, 292/337
International Classes:
E05B63/06
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Description:

This invention relates to an extension unit whereby the backset of a lock unit when installed in a door may be materially increased, the present application being a continuation in part of my co-pending application Serial Number 277,768, filed June 7, 1939, now Patent No. 2,250,036, dated July 22, 1941, entitled "Backset extension unit for door locks." "Backset" is a term used in the door lock and building industry, and refers to the measurement or distance between the edge of the door and the center of the lock spindle. The average backset on inside doors is 21/2 inches, and the backset on outside or so-called front doors, 2% inches. Architects and builders are constantly attempting to make innovations, that is, to introduce new features, novelties, new designs, etc., and recently it has become the vogue in certain types of buildings and other structures materially to increase the backset in door locks.

In some instances this is carried to such an extreme as to position the spindle and knobs approximately at the center of a door.

In certain types of lock, for instance in the so-called mortise type, the latch bolt and the latch bolt actuating mechanism, to wit, the spindle, the rollback member, the knobs, etc., are carried by a single housing. To increase the backset in that type of lock it would be necessary to increase the length of the housing and of much of the mechanism within the housingobviously, a very costly procedure. There is another type of door lock which is divided into two separate units, each enclosed in its own housing.

These units are known as the latch bolt unit and the latch bolt actuating unit. In this type of lock, increase of the backset has been accomplished by lengthening the housing and contained mechanism of the latch bolt unit. This is also costly and is not very satisfactory, and it compels the lock manufacturer to furnish the latch bolt unit in varying lengths depending upon the backset desired.

Whether the housing and mechanism of the mortise type of lock is lengthened, or the latch bolt unit of the latter type of lock is lengthened, the cost to the lock manufacturer is excessive; and besides that, a considerable stock of locks of varying lengths must be carried to meet the specific measurements and lengths demanded b different architects and builders.

The object of the present invention is to improve locks of the two-unit type, that is, in whicl the lock mechanism consists of two separable units to wit, a latch bolt unit and a latch bolt actuating unit; and particularly, to provide an intermediate or extension unit, insertable between the latch bolt unit and the latch bolt actuating unit, whereby any backset may be obtained without change or increase of the length of either of the first named units.

The invention is shown by way of illustration in the accompanying drawings, in which Fig. 1 is a central longitudinal vertical section, taken through the type of lock heretofore referred to, which is known as a two-unit lock, the section showing the intermediate or extension unit in position between the aforementioned units; Fig. 2 is a similar section showing the invention applied to a door lock employing a deadlocking latch or bolt; Fig. 3 is a longitudinal horizontal section, taken at right angles to Fig. 1 or Fig. 2, of the extension or intermediate unit; Fig. 4 is a perspective view of the retractor bar carried by the extension or intermediate unit; Fig. 5 is a perspective view of the latch bolt actuating unit; Fig. 6 is a perspective view of the extension or intermediate unit; Fig. 7 is a perspective view of the latch bolt unit; and Fig. 8 is a fragmentary perspective view of a door, showing the manner in which it is bored and otherwise prepared for the reception of the type of lock shown in Figs. 5, 6 and 7.

The type of door lock mechanism to which the present invention appears most readily applicable is the separable type, that is, a lock in which the latch bolt mechanism is contained in one housing or unit and the latch bolt actuating mechanism in another housing or unit, the two housings with their enclosed mechanism being separably insertable in a door when installing the lock. In order that the extension unit forming the subject matter of this application may be fully understood, a brief description of the latch bolt unit and the latch bolt actuating unit will be submitted.

The latch bolt unit (see Figs. 1 and 7) comprises a face plate 2 which is adapted to be secured to the outer edge 3 of a door A by means of screws 6. The face plate has an opening formed therein through which the latch bolt 7 extends in the usual manner. Secured to the rear side of the face plate is a cylindrical elonI gated housing 8; the rear or inner end of this housing is closed by an end plate 9, but this S55 plate has an opening formed therein, which forms a guide and permits the inner end of a retractor bar 10 to extend therethrough. The forward end of the bar is secured to the latch bolt 7; hence when a pull is exerted on the retractor bar the latch bolt will be retracted. Conversely, when a pull is not exerted, a spring 1 interposed between the latch bolt and the end plate 9 will maintain the latch bolt in extended position.

The latch bolt actuating unit is generally indicated at B (see Figs. 1 and 5). It comprises 1 a housing 14, which is materially larger in diameter than the latch bolt housing. Extending through the housing and journaled therein is a spindle 15, and formed on the spindle is a rollback member 16, which imparts reciprocal move- 1i ment to a retractor 17 when the spindle is rotated. The retractor is provided at its forward end with a pair of spaced fingers 18 which under normal conditions engage a pair of lugs- 19: formed on the inner end of the retractor bar 21 10. This normal condition will exist as long as the standard backset, for instance 21 inches, is employed, but where the backset is-increased, engagement between the fingers 18 and the lugs 19 can obviously not be maintained, unless the latch 2; bolt, retractor bar 10, and housing 8 are proportionately lengthened. This of course is not feasible from a manufacturing point of view, and is the main reason for providing an extension or intermediate unit, generally indicated at C, which 3( may be interposed between the latch bolt unit and the latch bolt actuating unit.

The extension or intermediate unit is best illustrated in Figs. 1, 2, 3, 4 and 6. It comprises an elongated cylindrically-shaped housing 20 having the same diameter as the latch bolt housing 8. One end of the housing 20 is open, as indicated at 21, and is provided with a pair of inturned lugs 22, while the other end is provided with a pair of outwardly-turned lugs 23. The 4C end of the housing adjacent lugs 23 is closed by a disc 24 and a pair of in-turned lugs 25. Slidably mounted within the housing 20 is a retractor bar 26. One end of the bar extends through the disc 24 and is guided thereby, while 4E the opposite end is provided with a head, generally indicated at E, which serves as a guide and also as a connector. The head consists of a pair of plates 27 connected by a side plate 28.

The plates 27 are riveted, welded, or otherwise secured to the bar 26 as shown at 29, and the forward ends of the plates are bent inwardly and shouldered, as shown at 30, to form a pair of fingers which are adapted to receive and embrace the lugs 19 formed on the inner end of the retractor bar 10 of the latch bolt unit. The opposite end of bar 26 is provided with a pair of lugs 19a, and these are adapted to be received and embraced by the fingers 18 of the retractor 17 carried by the latch bolt actuating unit. A spring 32 surrounds the bar 26; it is interposed between the disc 24 and a shoulder 26a on the bar 26, and as a compression type of spring is employed, the tendency is to move the bar in the direction of the arrow (see Fig. 3). Such movement is, however, limited by a stop lug 33 formed on the side of the bar, as this lug engages the disc 24 and thereby limits movement in the direction of the arrow; on the other hand it permits movement in the opposite direction, as will hereinafter appear.

In actual practice, when a lock of this character is to be installed in a door, two holes must be drilled with a wood bit or-similar tool. One hole (see Fig. 8) is bored transversely through the door, as indicated at 40, and receives the latch bolt actuating unit indicated at B. The other hole 41 is drilled through the edge of the door in a direction at right angles to the first hole, and this hole serves the function of receiving the intermediate unit C and the latch bolt unit shown in Fig. 7. The distance between the edge of the door and the center of the hole 40 depends upon the backset desired, and may 0 in extreme instances be great enough to place the hole substantially in the center of the door.

In this particular instance let it be assumed that a backet of six inches is desired. If that is the case, the extension or intermediate unit will have 5 to be approximately 31/2 inches long, as the normal backset is 2% inches. If the backset on another door is to be eight inches, the extension unit will have to be 51/2 inches long. These dimensions are merely submitted to bring out the 0 fact that the length of the extension unit varies; that is, the manufacturer, instead of changing the standard dimensions of the latch bolt units, merely supplies extension units of varying lengths, and will under normal conditions have a 5 sufficient number of different lengths on hand to take care of current demand.

When a door has been bored and the face countersunk for the reception of the face plate 2 of the latch bolt actuating unit, as clearly shown Sin Fig. 8, the installation of the: lock will be accomplished as follows: The latch bolt unit 7 and the intermediate: or extension unit: shown in.Fig. 6 are first connected end to end, that is, the adjoining ends shown in Figs. 6 and 7 are connected. This is accomplished by placing the lugs 19 at the side of the open end 21 of the housing 20, then by moving the latch bolt unit laterally with relation to the intermediate unit, or vice versa, the lugs will pass behind and under the fingers 30 formed on: the forward end of the retractor bar 26. At! the same time the in-turned lugs 22 on the housing 20. of the intermediate unit will pass behind outwardlyturned lugs 22a formed on the inner end; of the latch bolt unit, the interlock between the several lugs and fingers being clearly shown, in Fig. 1.

By this method of interlock the retractor bars and 26 are connected, and:so are the two housings of the respective units. With the two units thus Sconnected, it is only necessary to insert them endwise through the opening 41 formed in the door, and then to secure the face plate by inserting the screws 6. When so inserted, the lugs 19a formed at the inner end of the retractor bar 26 will project a slight distance into the opening 40 formed in the door, and so will the out-turned lugs 23.

Hence when the latch bolt actuating unit is inserted endwise through the opening 40, or in a direction transverse of the door, the fingers 18 of the main retractor will pass over the lugs I Saof the retractor bar 26 and engage the: same. An interlock between the inner end of the housing 20 of the unit C and the housing 14 of the:unit B will also be made, as an opening 47 is formed in the housing 14. This opening serves two functions: first, it permits the inner end of the retractor bar 26-or in other words, the lugs 19a-to extend into the housing 14, where they can be gripped or engaged by the fingers 18; secondly, the opening forms two opposed: shoulders 48, which engage the outwardly-turned lugs 23 formed-on the inner end of the housing 20 of the intermediate unit, Thus an interlock is formed between the housings 14 and 20 at one end, and between the housings 20 and- 8 at the opposite end. Also, an interlock is formed between the fingers 18 of the main retractor and the inner end of the retractor bar 26, and an interlock is likewise formed between the fingers 30 at the opposite end of the retractor bar 26 and the lugs 19 formed at the inner end of the main retractor bar 10 of the latch bolt unit. Hence, when the spindle is rotated, the rollback member 16 will engage the inner face of the retractor 17, forcing, this to move inwardly between guides 17a formed within the housing 14, and against the tension of a spring 17b. During such inward movement of the retractor 17, fingers 18 engage the lugs 19a of the retractor bar 26. The fingers 30 at the opposite end of the retractor bar engage the lugs 19 of the retractor bar 10, and both bars will thus move in unison in an inward direction with the retractor 17, and thus cause retraction of the latch bolt 7. On the other hand, when the spindle is released, spring 17b will force the retractor 17 in a forward or outward direction.

The springs 32 and I will at the same time force the retractor bars 26 and 10 in an outward direction, and the latch bolt 7 will accordingly be projected. In other words, a backset of any distance may be obtained, without in any way altering the construction and operation of the two standard units employed, to wit, the latch bolt actuating unit and the latch bolt unit, as intermediate units of any desired length may be furnished whereby a connection is made between the retractor 17 and the retractor bar 10.

In Fig. 1, the extension unit is illustrated in connection with an ordinary door latch. The extension is, however, equally applicable to socalled "deadlocking" door bolts or latches, as illustrated in Fig. 2. In this type of latch, there is a floating cam plate 50, which is retracted in unison with the main retractor bar, indicated at 51, when the main latch bolt la is retracted by means of the retractor bar 26 and the main retractor 17. This floating cam plate must remain stationary and in the position shown in Fig. 2 when the latch bolt 7a and the deadlocking bolt 7b are depressed, as for instance when a door is slammed or closed, as it is only in this position that the deadlocking of the latch bolt la can be effected. If the latch bolt 7a should be depressed while the door is closed, by means of a jimmy or like tool, it would be possible for the cam plate to move with it, due to friction between the cam plate and the retractor bar 51; and if this happened, the deadlocking mechanism would fail. and the door would be opened. Such movemeni of the cam plate is, however, prevented in the present instance, as spring 32 holds the retractol bar 26 in the full-line position shown in Fig. 2 In this position, fingers 30 engage shoulders 56 on the cam plate, and thus secure it against movement when the latch bolt 7a is depressed either by closing of the door or when an attempt is made to depress it by a jimmy or similar tool.

The use of the spring 32 is accordingly important, as it prevents floating of the cam plate except at the times when it should float. If it were not for this factor, the spring 32 could be entirely eliminated, as the tension of the latch bolt projecting spring, for instance the one shown at 1 in Fig. 1, is more than sufficient to actuate not only the main latch bolt I or 7a, but also to restore the retractor bar 26 to normal position after actuation.

While certain features of my invention have been more or less specifically described and illustrated, I wish it understood that changes may be resorted to within the scope of the appended claims, and that the materials and finish of the parts employed may be according to the wishes of the manufacturer or to varying conditions of use.

Having thus described and illustrated my invention, what I claim and desire to secure by Letters Patent is: 1. An extension unit of the character described, comprising a tubular housing adapted to be interposed between the latch bolt retracting mechanism and the latch bolt of a lock, a bar slidably mounted therein, an end closure at one end of the housing through which one end of the bar extends and in which it is guided, a pair of lugs on the same end of the bar adapted to be connected with the retracting mechanism, a head member on the opposite end of the bar and forming a guide therefor, and a pair of fingers on the head member adapted to be connected with the latch bolt.

2. An extension unit of the character described, comprising a tubular housing adapted to be interposed between the latch bolt retracting mechanism and the latch bolt of a lock, a bar slidably mounted therein, an end closure at one 4e end of the housing through which one end of the bar extends and in which it is guided, a pair of lugs on the same end of the bar adapted to be connected with the retracting mechanism, a head member on the opposite end of the bar and forming a guide therefor, a pair of fingers on the head member adapted to be connected with the latch * bolt, a spring interposed between the head member and the closed end of the housing to urge the ; bar in one direction, and a stop lug to limit said * 55 movement.

WALTER R. SCHLAGE.