US2801871A - Bar latch for doors - Google Patents

Description

Aug. 6, 1957 c. c. RADCLIFFE 2,301,871

BAR LATCH FOR DOORS Filed Nov. 8, 1954 FIG. I 3/ 32 36 24 rn I n FIG.3

' INVENTORIQ CHARLES c. RADCLIFFEI ATTORNEYS.

2,801,871 BAR LATCH FOR DOORS Charles C. Radcliffe, Chicago, Ill. Application November 8, 1954, Serial No. 467,448

1 Claim. (Cl. 292 -267) My invention relates to a bar latch for locking a door in partly opened position. This type of latch is popular in'respect to forming a fixed stop for the door when it has been opened part-way. However, the extent to which the conventional bar latch permits the door to be swung creates an opening so wide that an intruder could reach into the room space behind the door or wedge his foot in the door to prevent the same from being closed. Also, with the opening so wide, a sufiicient leverage is obtained against the bar for the intruder to force the door and pull the bar off the jamb. It is therefore one object of the present invention to provide a latch bar which allows only a small opening of the door, so that the occupant of the room space may gain a direct view of the person on the outside or by means of a hand mirror.

A further object is to provide a latch bar formed with a sturdy base plate, the latter being fastened in several places to the jamb of the door for strong resistance in case the latch bar is forced.

Another object is to provide means in the latch bar for seating the locking bolt in any one of a number of hookshaped cavities, according to the extent to which the door is to be opened.

An additional object is to form the latch bar with a medial slot through which the locking bolt travels when the door is opened, the aforesaid cavities leading from the upper edge of the said slot, and the locking bolt having means for automatically lodging in any desired cavity.

A still further object is to provide a bearing for the locking bolt, and spring means in the bearing to normally urge the locking bolt in a rising direction, whereby to find a seat in any cavity opposite the same.

Another object is to impart a curvature to the latch bar conforming to the travel of the locking bolt in order to insure the proper engagement of the same at all points along the latch bar.

An important object is to design the novel latch bar along lines of compactness and simplicity.

With the above objects in view, a better understanding of the invention may be had by reference to the accompanying drawing, in which- Fig. 1 is a front view of a portion of a door and jamb showing the latch bar in the normal or unlocked position;

Fig. 2 is a top plan view of the latch bar installation; and

Fig. 3 is a section on the line 33 of Fig. 2.

In accordance with the foregoing, specific reference to the drawing indicates the door at and the jamb on the closing side at 11. The basic arrangement of the latch bar installation is the same as usual, namely, a locking bolt carried by a fixture 16 attached to the door, and the latch bar 20 carried by a base plate 21, the latter being attached to the jamb on the side facing the door.

As noted in Fig. 1, the locking bolt fixture 16 is attached to the door by a set of screws 23; and the bolt has the usual circular head 24 on the side facing the latch bar.

United States Patent 0 The base plate 21 for the latch bar is ample in size and firmly secured to the jamb by five screws 28 in order to present strong resistance to influences tending to force the latch bar. The base plate is made with a clearance opening 30 on the inner side for the entrance of the locking bolt head 24 when the door is closed; and the upper and lower parts of the base plate are thickened to journal pintles 31 cooperating with ears 32 of the latch bar to connect the same pivotally to the base plate.

The latch bar 20 is made with a continuous marginal side flange 35 for purposes of reinforcement. Its inner end has a broad entrance 36 leading into the conventional longitudinal slot 38 made in latch bars of the type under consideration and forming the passage along which the locking bolt 15 travels when the door is opened and the latch bar is swung toward the door.

While in conventional latch bars the slot 38 is plain, the novel latch bar contains a longitudinally spaced series of pockets 39 communicating with the upper side of the slot 38. As clearly seen in Fig. 1, these pockets are hookshaped and preceded by leading edges 40.. The locking bolt 15 is adapted to rise along any selected leading edge 40 while it is carried through the slot 38 and caused to seat in the corresponding pocket 39. In the instant case, the locking bolt 15 is pivoted horizontally at 42 in the door fixture 16, and urged by a spring 44 to bear upwardly with its inner or headed portion.

When the door is opened and the latch bar is swung toward it, the tendency of the bolt will be not only to enter the slot 38, but climb immediately into the first pocket 39, stopping the progress of the door. The door is now locked to the extent of a narrow opening approximately one inch wide through which the occupant of the room space inside the door may look and ascertain Who is approaching the door. Also, in case the approaching person attempts to keep the door open by wedging his foot in the same, it is obvious that the aforesaid space will be too small for that purpose. However, should the caller deserve a brief period of attention or the convenience of passing a letter or small object through the door, the occupant may raise the outer end portion 45 of the locking bolt 15 in order to have the same clear the first pocket 39, and allow the door to be opened a further distance limited by the second pocket in line. It goes without saying that this process can be repeated to the extent of the full length of the latch bar it a wider door opening is desired.

With the door looked through the agency of the first pocket 39, the narrow door opening will not afford a sufiicient hold or leverage to an intruder in case he attempts to force the latch bar, so that the latter has a high safety factor against the forcible entrance of an intruder. In other words, the latch bar affords the assurance of safety against breaking in after the narrow opening of the door permits the occupant to determine that the visitor is not welcome. Also, such narrow opening makes it difficult if not impossible for anyone to insert a finger or tool designed to unseat the locking bolt from the first pocket 39, particularly as the inward pressure upon the door increases the retentive hold of the pocket on the locking bolt. Further, the broad and amply secured base plate 21 will offer strong resistance to attempts to force the door and allow the occupant sufiicient time to institute an alarm if considered necessary. Finally, it will be noted from Fig. 2 that the latch bar 29 is curved longitudinally, this being for the purpose of conforming to the are described by the door and calculated to follow the travel of the locking bolt.

It will now be apparent that the novel latch bar in stallation supplements the conventional design not only with a series of steps for opening the door to different degrees, but also with an initial safeguard which prevents 0 the forcing of the door while the same afiords a limited opening for ascertaining the identity of a caller. This and the. other features of the device are accomplished by a pair of units which are sturdy and simple in construction.

While I have described the invention along specific lines, various minor changes or refinements may be made therein without departing from its principle, and I reserve the right to employ all such changes and refinements as may come within the scope and spirit of the appended claim.

I claim:

A door latch comprising a fixture attachable to a door and carrying a bolt pivoted for vertical swinging movement, the bolt having a shank terminating in an enlarged head, the bolt head and a part of said shank projecting beyond said fixture and the door edge, a base plate attachable to the door jamb opposite said fixture, and a latch bar pivoted to the base plate, spring means in said fixture for urging said bolt upwardly through engagement References Cited in the file of this patent UNITED STATES PATENTS 351,147 Adams Oct. 19, 1886 1,524,088 Ernst Jan. 27, 1925 1,537,436 Graf May 12, 1925 FOREIGN PATENTS 28,851 Great Britain Apr. 11, 1907 321,099 Great Britain Oct. 31, 1929

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