Patent Publication Number: US-3874716-A

Title: Interior security latch

Description:
United States Patent [191 Bancroft [451 Apr. 1, 1975 INTERIOR SECURITY LATCH [75] Inventor: Joseph C. Bancroft, McComb, Miss.  
 [73] Assignee: Croft Metals, Inc., McComb, Miss. 221 Filed: Oct. 23, 1973 [21] Appl. No.: 408,498  
 [52} US. Cl 292/175, 70/DIG. 52, 292/145, 292/DIG. 49 [51] Int. Cl. Ec 1/04 [58] Field of Search /DlG. 52; 292/145, 175, 292/D1G. 49  
 [5 6] References Cited UNITED STATES PATENTS 413,245 10/1889 Richmond 292/175 1,271,117 7/1918 Barnard 292/175 2,971,789 2/1961 Weaver 292/ 3,751,087 8/1973 Hawkins 292/ FOREIGN PATENTS OR APPLICATIONS 200,258 7/1923 United Kingdom 292/ Primary Examiner-Albert G. Craig, Jr.  
 [57] ABSTRACT A low cost security latch which may be applied to windows, doors, cabinets, or other aperture closures having a moving component comprises a slotted mounting bracket which may be formed as a thin metal stamping or molded component, a latch bolt which may also be formed as a thin metal stamping and which slides in the mounting bracket slots, and a compression spring which is mounted between a shelf on the mounting bracket and the latch bolt and which acts as an offset toggle to retain the latch bolt in fully engaged and fully disengaged positions.  
 1 Claim, 10 Drawing Figures INTERIOR SECURITY LATCH BACKGROUND oF THE INVENTION 1. Field of the Invention The invention is related to devices for securing windows, doors, and the like, and commonly referred to as latches or locks.  
 2. Description of the Prior Art There have been innumerable types of locks and latches devised for securing a moving component in a window, door structure, cabinet, or the like, in a closed or locked position. Many of such latches and locks have been formed of metal stampings, castings, and the like. However, with the increase in criminal breakins with sliding glass windows, sliding doors, and the like, there has built up a demand for an auxiliary low cost lock which can be attached to prefabricated sliding glass doors having the standard lock in the center of the door, to windows and like applications, and which can be provided as a low cost auxiliary latch or lock to provide positive deadbolt type locking. In particular, the prior art indicates a need for a security latch that can be attached as an auxiliary positive lock to any conventional type window or door and that can be obtained at less expense than those now on the market. Also, many families are faced with the need for a low cost security lock to prevent young children from entering kitchen cabinets and the like.  
 SUMMARY OF THE INVENTION The security latch of the invention comprises a slotted latch bracket which can be attached to any fixed member, e.g., a frame jamb, a latch bolt which is slidably mounted in the latch bracket slots and a compression spring mounted between a shelf formed on the latch bracket and the latch bolt. A receptor slot is located in the abutting moving member, e.g., a panel jamb, to receive the latch bolt when in a closed position. The compression spring is so designed and mounted as to act as an offset toggle to hold the latch bolt in positively engaged and positively disengaged positlons.  
 DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view showing the latch mechanism of the invention in an open position and applied to a mating frame and panel jamb, a fixed wall, and a door panel being depicted in dashed lines.  
  FIG. 2 is a perspective view similar to FIG. 1 but showing the invention latch mechanism in a locked position.  
 FIG. 3 is an end view of the mechanism taken in the direction 3-3 of FIG. 1.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS For purposes of illustrating an application of the invention, the security latch mechanism of the invention is shown applied in FIGS. 1 and 2 to a typical sliding door formed of extruded components of a popular and conventional type. In particular, the frame jamb represents a fixed member secured to a fixed wall 11. The door panel jamb 12 mounting an associated door panel 13 represents an abutting moving member having a receptor slot 14 located to receive the latch bolt, later described, in a closed position. I  
  The security latch mechanism of the invention basically comprises three components and a fourth component which may be used, if desired, and each of which are designed to be mass-produced at nominal cost. The latch bracket 15 provides a sliding support for latch bolt 18 and is intended to be attached to the illustrated fixed jamb member 10. In the drawings, bracket 15 is shown secured to jamb l0 and wall 11 by means of screws 16 mounted in elongated holes 17 which allow for vertical adjustment. The latch bolt 18 slidably mounts in a pair of opposed slots 19, 20 which, as illustrated, are formed in a U-shaped bent portion of latch bracket 15. An end wall 21 of this U-shaped portion is formed with a shelf 22 which is bent upwardly within the U-shaped portion and perpendicularly to end wall 21 to provide a spring supporting shelf 22. Shelf 22 includes an aperture 25 which receives one lower end of a bent leaf compression spring 26. The other upper end of spring 26 is fitted into an aperture 28 which is provided in the forward end of the latch bolt 18. Latch bolt 18 further includes a downwardly turned handle portion 30 having a reduced section 31 adapted to and which preferably receives a press fitted knob 32 which serves as a comfortable operating handle and may be molded of plastic or the like. An inclined edge 33 on the forward locking portion of latch bolt 18 is oriented towards the moving member, i.e., door jamb 12, which serves to automatically throw the latch bolt 18 into a disengaged position in the event it is inadvertently struck by the moving member 12.  
  Leaf spring 26., in the embodiment described, has a bent, central U-portion 26a which provides resiliency and two extending flat end portions 26b, and 26c having reduced end sections as shown and which mount in the previously mentioned apertures 25, 28.  
  It can be seen that the latch bracket 15, the latch bolt 18, and the spring 26 all lend themselves to being formed of very low cost metal stampings. For example, a single flat metal stamping, preeut to shape, can be bent to provide the mount 35, the arm and wall portion 36, the end wall 21, the sidewall 37., the shelf 22 and the rectangular slots 19,20. In the same sense, a flat metal strip of rectangular cross section can be precut and bent to provide the bolt portion 29 and the handle portion 30 of latch bolt 18. A single low cost plastic molding may be employed to provide the handle 32 when desired for added comfort.  
  In use, latch bracket 15 is adjustably secured by appropriate mounting screws 16, or other fastening means, in holes 17 to insure alignment and engagement of the latch bolt 18 with the receptor slot 14. The latch bolt 18 is moved from the open position of FIG. 1 into the closed position shown in FIG. 2 which causes spring 26 to pass its neutral center line and force the latch bolt 18 into a fully engaged position. Inward movement is limited by notch 40 engaging sidewall 37 and outward movement by the limits of travel of spring 26. In the locked position, latch bolt 18 will penetrate and positively engage itself in receptor slot 14 and is prevented from being disengaged by a normal vibration or jarring action. In retracting or pulling the latch bolt 18 away from the receptor slot 14, spring 26 is again carried past its neutral center line in the opposite direction which causes the latch bolt 18 to be forced into a fully disengaged position.  
  While shown in the form of a bent strip, spring 26 may take the form of being a coiled compression spring 50 as shown in FIG. 5. In this embodiment, instead of employing the apertures 25, 28, inwardly pressed tabs 46, 47 may be provided in the latch bolt 18 and shelf 22 to engage the ends of the coiled compression spring 50.  
  In another embodiment, the purposes of spring 26 are served by a coiled compression spring 52 as shown in FIG. 6 and which has end portions 53, 54 that are adapted to be received by the apertures 25, 28 of the first embodiment.  
  While shown mounted in a position for horizontal movement of latch bolt 18, the security latch of the invention readily adapts to being positioned such that latch bolt 18 may move vertically. Also, as shown in FIG. 7, latch bolt 18 may, if desired, be stamped and formed essentially flat and with inwardly bent tabs 60, 6I to provide a handle portion. Also, as shown in FIGS. 8 and 9, the latch bracket may be formed in a variety of configurations to fit various doors, windows, cabinets, and the like. In FIG. 8, the mount 35 and arm 36 are in the same plane and in FIG. 9 the mount 35 is bent parallel to wall 21.  
  While the embodiment illustrated in FIGS. 1, 2 and 3, which utilizes the shelf 22 has the advantage particularly of being able to retract when the latch bolt 18 is inadvertently struck, as previously explained, the need for shelf 22 can be eliminated as illustrated in the embodiment of FIG. 10. In FIG. 10, the slots 70, 71 occupy a plane parallel to the plane of wall 21 and the ends of spring 26 are received by an aperture 72 in wall 21 and an aperture 73 in latch bolt 18. The receptor slot, comparable to slot 14, is of course oriented to the orientation of latch bolt 18 in FIG. 10 but in other respects, the operation of the latch mechanism is as previously explained.  
  To further illustrate the various forms of manufacture which can be employed to mass-produce the latch mechanism of the invention, it may be noted that the notch 40 may be replaced by formed tab 41 as shown in FIG. 7. Thus, either notch 40 or tab 41 may be employed as a positive stop for limited inward travel of the latch bolt 18. Spring 26 can, of course, be located and designed so that central portion 26a of spring 26 strikes the arm-wall portion 36 in the locking position of FIG. 2 and strikes wall 37 in the unlocked position of FIG. 3, thus limiting travel.  
  From the foregoing, it can be seen that the security latch mechanism of the invention provides a positive deadbolt type lock but with components which can be mass-produced at nominal expense.  
 What is claimed is:  
  I. A glass sliding door assembly comprising, in combination:  
 a. a glass door panel laterally movable from a Closed b. a wall secured building frame slidably mounting said panel and formed of extruded members including an extruded vertical frame jamb positioned for securement to said panel jamb when in said closed position; and  
 c. a security latch mechanism for securing said panel jamb to said frame jamb when in said closed secured position, said mechanism comprising:  
 1. a latch bracket formed of a first elongated strip of thin sheet material, said bracket having at one end a flat mounting portion with plural apertures for receiving fastening means to secure such mounting portion to said frame jamb and having at an opposite end a U-shaped bolt support portion appended to said mounting portion, said bolt support portion having a central base and perpendicular thereto opposed sidewall portions with oppositely positioned rectangular-shaped slots for receiving a latch bolt and with one of said sidewall portions forming a perpendicular continuation of said mounting portion, said bracket further having a spring support wall portion with a spring mounting aperture therein appended perpendicularly to said base portion and in a plane generally parallel to the disposition of said bolt slots;  
 2. a latch bolt formed of a second elongated strip of thin sheet material of rectangular cross section having a forward bolt portion slidably mounted in said bolt receiving slots for inward locking and outward unlocking positioning and having a rearward handle portion extending from and formed perpendicular to said bolt portion, said bolt portion having intermediate its length a spring mounting aperture opposite and mating said latch bracket wall spring mounting aperture, the forward locking end of said bolt portion being formed to engage said panel jamb slot to lock said frame jamb thereto; and  
 3. a compression spring mounted within said U- shaped configuration and formed as a leaf spring of a thin sheet strip having linear end portions and a central compressible, semi-circular portion, one linear end portion being pivotally mounted in said latch bolt mounting aperture and the opposite linear end portion being pivotally mounted in said spring support wall portion mounting aperture, said spring being mounted on said respective spring mounting apertures to provide a toggle effect such that when said latch bolt is moved inwardly, said compression spring pivots on said wall portion and tilts in the same direction to force said latch bolt towards a positive locking position and when said latch bolt is moved outwardly said compression spring pivots and tilts oppositely to force said latch bolt toward a positive unlocked position.  
  UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,874,716 Dated April l, 197s Inventor-(9Q Joseph C. Bancroft It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 Col. 4, line 13, after &#34;closed&#34; the word --secured-- should be inserted.  
 Signed and sealed this 15th day of July 1975.  
 (SEAL) Attest:  
  C. MARSHALL DANN Commissioner of Patents and Trademarks RUTH C. MASON Attesting Officer