Device for discouraging the jimmying of door locks
United States Patent [19] Pratt Apr. 1, 1975 [76] Inventor: Robert E. Pratt, PO. Box. 100,  
 Somers, Conn. 06071 [22] Filed: Aug. 2, 1973 [21] Appl. No.: 384,986  
 [56] References Cited UNITED STATES PATENTS 12/1957 Henry 292/346 9/1964 MacLaughlin 292/346 FOREIGN PATENTS OR APPLICATIONS 205,943 11/1923 United Kingdom 292/346 OTHER PUBLICATIONS Primary Examiner-Robert L. Wolfe Attorney, Agent, or Firm-DeLio and Montgomery 57 ABSTRACT Jimmying of door locks by forcing the retraction of the door lock bolt is prevented or discouraged by a device which may be attached either to the door jamb or to the end wall of a door containing the door lock. The device has a first plate-like mounting member and a second plate-like member angularly connected to the first member, the second member being resiliently biasable towards the first member in response to contact with the other of the door member and the end wall upon which the first member is not mounted when the door is swung to a closed position. The device thereby blocks the clearance space between the door jamb and the end wall adjacent the bolt, preventing contact of a jimmying device with the bolt.  
 6 Claims, 12 Drawing Figures EB&#39;JENTEU APR 1 1935 1874,? 17  
 INSIDE Y oursme Z BACKGROUND OF THE INVENTION This invention relates to devices for use with a door lock for preventing or discouraging jimmying of the lock.  
  The retractable bolts commonly present in door locks are either live or dead. In the latter case the bolt is retractable only by insertion of a key or the turning of a knob. In the case of a live bolt lock, however, the bolt rides in a channel under bias by a spring or other resilient means and canbe retracted by contact of an instrument with the bolt itself, as well as by turning of a key or knob. Additionally, many live bolts have slanted tips for the purpose of easier sliding contact with a striker plate than would be the case with a square or somewhat rounded tip. Most live bolts can thus be forced to retract by inserting into the clearance space between a door jamb and the end wall of a door a flexible instrument such as a plastic card or the like. When the head of the bolt is slanted, the ease of forced retraction thereof by a flexible instrument is greatly enhanced. Accordingly, unless such live bolts are replaced by dead bolts, a great proportion of common household door locks can be easily and quickly jimmied open.  
  An inexpensive and easily mounted device would therefore be useful which, although it may not prevent jimmying of a live bolt lock in all instances, forcing will at least take so much time as to discourage jimmying by someone not authorized for access to a building. Because an intruder usually must work quickly to avoid notice, he will not expend much further effort when his initial attempts to jimmy a lock are thwarted.  
 OBJECTS AND SUMMARY Accordingly, an object of the invention is to provide a new and improved device for use with a door lock for the prevention or discouragement of jimmying of the door lock.  
  Another object is to provide a new and improved device which is simple and inexpensive, and which can be easily mounted by the average home owner to prevent or discourage unauthorized access.  
  These and other objects, features and advantages of the invention will be apparent from the specification which follows.  
  In summary outline, the device of the invention includes a first plate-like member adapted for mounting on either a door jamb or on the end wall of a door containing a door lock, and a second plate-like member angularly connected to the first member, the second member being resiliently biasable toward the first member in response to contact with the other of the door jamb and end wall when the door is swung to a closed position. As a result the device will block the clearance space between the door jamb and the end wall adjacent the door bolt, and thus prevent contact of a jimmying device with the door bolt.  
  The invention accordingly comprises a device possessingthe features, properties, and the relation of element which will be exemplified in the device hereinafter described, and the scope of the invention will be indicated in the claims.  
 DETAILED DESCRIPTION For a fuller understanding of the nature and objects of the invention, reference is had to the following description taken in conjunction with the accompanying drawings, in which:  
  FIG. 1 is a partially diagrammatic, horizontal section of a closed door, showing a door jamb and a door lock with which is associated a device of the invention;  
 FIG. 2 is a detailed view of portions of FIG. 1;  
  FIG. 3 is a view similar to that of FIG. 2 showing the configuration of a device of the invention when a door is open;  
  FIG. 4 is a somewhat enlarged elevational view along the line 4-4 of FIG. 2 showing a striker plate of a door lock and a device of the invention in relation thereto;  
  FIG. 5 is a somewhat enlarged elevational view along the line 5-5 of FIG. 2 showing an auxiliary structural element which may be used with a device of the invention;  
  FIG. 6 is a plan view of a device of the invention before it is formed into an operative shape;  
  FIG. 7 is an end view of the device of FIG. 6 after it is formed into an operative shape;  
 FIG. 8 is a bottom view of the device of FIG. 7;  
  FIG. 9 is an enlargement of the view of the device of FIG. 7 illustrating a method of attachment;  
  FIG. 10 is a view similar to FIG. 9 showing relative position of structural elements of the device when a door is in a closed position;  
  FIG. 11 is a horizontal sectional view of a door end wall and door jamb with which is associated another embodiment of device of the invention and auxiliary element when a door is in closed position; and  
  FIG. 12 is a plan view, somewhat reduced in size, of the auxiliary structural element shown in end view in FIG. 11.  
  FIG. 1 shows a typical door 21 which swings inwardly to open as indicated by the arrow. As pictured, there fore, the right side of door 21 is the outside of the door. The door latch or lock typically includes rotatable handles 22 and a bolt 23 which is retractable by handles 22 or by a separate knob (not shown). A striker plate 24 typically is mounted on the opposing jamb 25 and a door stop surface 26 is positioned at right angles to the jamb for abutment with the closing edge of the door. A door bolt receiving slot 27 is located in the jamb 25, the striker plate 24 having an aperture of dimensions effective to guide the bolt 23 into the slot 27. A clearance space of about 3/16 inch is normally provided between the end wall 28 of door 21 and jamb 25. A bolt 23 typical of live bolts in many buildings is spring loaded and has a slanted tip 29. The bolt retracts when the slanted tip contacts the striker plate 24 as the door is being closed. The door is opened by turning a handle 22, the handle being engageable in a known manner with the bolt 23.  
  As more clearly shown in FIG. 2, absent a device 30 of the invention, the bolt 23 can be quickly made to retract by insertion of a jimmying device such as a flexible plastic card 31. The jimmying card 31 can be inserted around the outer edge of door 21 into the clearance space between the outer wall 28 and jamb 25, and then into operative contact with the slanted tip 29 of the bolt, thereby causing bolt 23 to retract. A gentle push against door 21 will then cause it to open. While live bolts with slanted tips 29 are most easily opened in this manner, it is possible that bolts with rounded tips may also be thus retracted. Bolts with flat tips and dead bolts, of course, are more difficult to retract by such jimmying devices. However, live bolts with slanted tips, as illustrated, are far more common than dead bolts, and therefore devices of the invention will have wide applicability.  
  FIGS. 1-4 and 6-10 illustrate one embodiment of a device 30 of the invention. As further explained below, a wear or rider plate 32 may be used with the device 30. The wear plate 32 is mounted either on the jamb 25 or, preferably, on the end wall 28 of door 21 adjacent the centering plate 33 for bolt 23, as shown in FIGS. 2 and 5. A device 30 of the invention includes a first plate-like member 34 and a second plate-like member 35 angularly connected to the first member 34. Second member 35 is resiliently biasable towards first member 34 upon contact with end wall 28 of the door in the arrangement illustrated in the Figures, or with the jamb 25 if the device 30 is mounted on the end wall 28 of the door rather than on jamb 25.  
  To provide the required resiliency of second member 35 the entire device is conveniently formed from a single piece of spring steel, in a manner to be explained with reference to FIGS. 6-8. Of course, the resiliency of member 35 with respect to member 34 may be provided in other ways, such as by the combination of a hinge joint between members 34 and 35 with a spring on the pin of the hinge. For convenience and economy of manufacture, however, the form of device 30 illustrated in the drawings is preferred.  
  As shown in FIG. 4, the second member 35 has a plurality of cutouts 36 therein for access of a tool such as a screw driver to drive fastening means such as screws 37 through first member 34 for tight mounting of the device 30 on jamb 25. As indicated, device 30 may be mounted either on jamb 25 or on end wall 28 of door 21, but the former is preferred in order to avoid impeding passage through the doorway or catching the clothing. However, in each form of mounting, the device 30 is positioned adjacent bolt 23 between the bolt and the outside of the door 21 so as to block contact of a jimmying device such as a flexible plastic card 31 with the tip 29 of bolt 23.  
  As illustrated in FIGS. 3, 4 and 6-10, first member 34 and second member 35 are elongated, having a length sufficient at least to block access to bolt 23. Preferably, the length of each member extends a distance beyond each side of striker plate 24, as shown in FIG. 4, so as to entirely bridge and block the region through which a jimmying device might be inserted. While the essential structure of device 30 is the combination of a first plate-like mounting or support member 34 and a second plate-like resiliently biasable closure member 35, the second member 35 preferably is provided with an outer edge 38 which is angled towards the surface to be contacted, which, in illustration, is a wear plate 32. This slightly extended angled edge 38 provides greater contact force with wear plate 32 than if member 35 were not so constructed. The contact force is further enhanced by an adjacent portion 39 which is bent or angled in a direction opposite from edge 38.  
  For still further enhancement of contact force of second member 35 against wear plate 32, portions of member 35 are right angle cut to form one or more ears 40. As most clearly shown in the closed door views of FIGS. 2 and 10, the cars 40 bend outwardly when member 35 is biased towards member 34, contacting rider plate 32. The double resilient bias provided by outer edge 38 and ears 40 effects a tight closure of the clearance space between the jamb and end wall of the door so as to prevent or to make extremely difficult passage of a jimmying device through the clearance space, as shown in FIG. 2.  
  The device 30 is mounted in any convenient manner on end wall 28 of door 23, but preferably on jamb 25. For most effectively secure mounting, as shown in FIGS. 2, 3, 7, 9 and 10, the device 30 may be formed with a longitudinal upstanding edge 41 angularly connected to first plate-like member 34. The device 30 in this form can thus be fixedly mounted on a jamb 25 which is trenched to receive the upright longitudinal edge 41. The edges of the drill holes in first plate-like member 34 preferably are upstanding so as to form protective shoulders 42 for flush setting of the heads of screws 37. The drill holes may be formed in any position and in any number for tight mounting of the device 30.  
  FIG. 6 illustrates how a device 30 of the invention may be formed from a single strip of suitable material, such as spring steel. With reference thereto, the initially single planar piece of steel is marked for cutting of drill holes to receive screws 37, for cutting of apertures 36 to provide access of a screw driver for driving the screws 37, for the cutting of ears 40, and for bending of the strip along bend lines 43, 44, 45 and 46 to the desired final shape. The various drill holes, apertures, and ears are then cut in a conventional way and the sectors of the device are formed by bending along the lines 43-46, with the result shown in FIGS. 7 and 8. Device 30 may then be mounted on a jamb 25 as shown in the open door view of FIG. 9. In the open position of the device the screws 37 adjacent edge 41 of the device may be driven directly but the apertures 36 are required for driving the screws 37 through the drill holes adjacent the point of connection of members 34 and 35.  
  If the clearance space between the jamb 25 and the end wall 28 of the door is greater than the conventional 3/16 inch, one or more spacer plates 47 may be employed between the first plate-like members 34 of the device and the jamb 25, as illustrated in FIGS. 11 and 12. The spacer plate 47 (FIG. 12) is elongated to approximately the same length as first plate-like member 34, and is provided with suitable slots 48 and drill holes.  
 49 corresponding with the drill holes in the first platelike member, for convenient mounting of the spacer.  
 member.  
 Another embodiment of device of the invention is illustrated in FIG. 11. With reference thereto, the device 50 is substantially identical to device 30 but lacks the longitudinal edge 41 of device 30. Device 50 is thus useful where the jamb 25 or other mounting surface either is not trenched or cannot be trenched to receive the longitudinal upstanding edge 41. In this case, the screws 37 will besufficient for tight mounting of the device. Rather than making both of such devices separately available, device 30 only may be manufactured and instructions given to the buyer to remove the edge portion 41 by cutting along bend line 43 (FIG. 6), thus adapting device 30 to surfaces which are not or cannot be trenched.  
  In operation, as shown in FIGS. 2, 3, 9 and 10, the device 30 will have the configuration of FIGS. 3 and 9 when the door is open but will bend to the configuration shown in FIGS. 2 and when the door is closed, by reason of abutment of edge 38 and ears 40 against the opposing surface, which in this case is the wear plate 32 on end wall 28 of a door. It will thus be evident that the device blocks the clearance space so that a jimmying device cannot contact the door bolt. When the door is opened in the usual way, that is, by the turning of door handle 22 or a knob operatively connected to bolt 23 (not shown), the second plate-like member 35 springs outwardly away from support plate-like member 34, remaining in this position until the door again is closed.  
  While second plate-like member 35 is shown with an arcuate cross section and angled edge portions 38 and 39, it will be evident that the angled outer portions 38 and 39 may be eliminated and second member 35 may be generally planar, assuming the force of contact of the edge of member 35 with an opposing surface is sufficient to prevent manipulation of a jimmying device under the outer free edge. In its preferred embodiments, as illustrated, the device includes angled outer portions 38 and 39 together with the somewhat arcuate cross section of member 35, thereby providing more than a sufficient degree of resilient force for normally immovable contact with an opposing surface. Accordingly, while in some instances the device of the invention will not absolutely prefent jimmying of a door lock, it will be effective to discourage unauthorized intrusion, by reason of the considerable time required to overcome its blocking function.  
  In view of the foregoing description it will be apparent that the invention is not limited to the specific details set forth therein for the purposes of illustration, and that various other modifications are equivalent for the stated and illustrated functions without departing from the spirit and scope of the invention.  
 What is claimed is:  
  l. A device for use with a door lock, which lock includes a bolt in an end wall of said door, said device comprising:  
 a first plate-like member adapted for mounting on either the jamb or the end wall of said door; and  
 a second plate-like member angularly connected to said first member and having a vertical free edge, said second member being resiliently biasable toward said first member in response to contact with the other of said door jamb and said end wall when said door is swung to a closed position, said second plate-like member being curved in horizontal section to present a convex surface toward the first plate-like member;  
 the portion of said second plate-like member adjacentsaid free edge lying at an angle to the first plate-like member greater than the angle between said members at their line of connection; whereby said device will block the clearance space between said door jamb and said end wall adjacent said bolt when said door is in said closed position, thereby preventing contact of a jimmying device with said bolt.  
  2. A device as in claim 1 wherein the portion of said second plate-like member adjacent said free edge is bent at an angle to the body of said second member, said portion being directed so as to resiliently bear against the other of said door jamb and said end wall when said door is in said closed position.  
  3. A device as in claim 2 wherein the body of said second plate-like member is cut substantially horizontally from a pointadjacent the line of connection to form at least one ear-like member adapted to resiliently bear against said other of said door jamb and said end wall when said door is in said closed position.  
  4. A device as in claim 2 wherein a free edge of said first plate-like member is formed at an angle to the body of said first member in a direction away from said second member, for embedding in said door jamb or said end wall, whereby said device is securely anchored.  
  5. A device as in claim 3 wherein said plate-like members are elongated and said second plate-like member is cut at two points to form a pair of said earlike members, whereby three point resiliently biased contact is provided against said other of said door jamb and said end wall when said door is in said closed position.  
  6. A device as in claim 1 which includes a flat wear plate affixed to the other of said door jamb and said end wall in a position to be contacted by said second platelike member.