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Publication numberUS3804454 A
Publication typeGrant
Publication dateApr 16, 1974
Filing dateJun 30, 1972
Priority dateJan 14, 1971
Publication numberUS 3804454 A, US 3804454A, US-A-3804454, US3804454 A, US3804454A
InventorsSimmons J
Original AssigneeSimmons J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Safety door guard
US 3804454 A
An auxiliary safety door guard having a flexible retainer member formed into two loop portions, one of which carries a screw type fastener adapted to secure the guard to a door frame member. The other loop may be deflected and releasably engaged about the door knob to prevent unauthorized entrance by restriction of the door opening. A collar member is positioned on the guard to occupy the space presented to the door exterior when the door is slightly opened to shield the cable from being severed from the exterior. Plastic sheathing on the retainer adds to the appearance and facilitates engagement and disengagement of the retainer. A method of fabricating the door guard is also disclosed.
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Description  (OCR text may contain errors)

United States Patent [191 Simmons 1 SAFETY DOOR GUARD [76] Inventor: J. V. Simmons, 800 N. Marsalis,

4 Dallas, Tex. 75208 22 Filed: June 30, 1972 21 Appl. No: 268,207

Related US. Application Data [63] Continuation-impart of Ser. No. 106,497, Jan. 14,

1971, abandoned.

[52] US. Cl. 292/262, 24/73 R, 29/433,

29/517 [51] Int. Cl. E05c 17/04, 823p 19/04 [58] Field of Search 292/262, 264, 246, 288,

References Cited Primary Examiner-Richard E. Moore Assistant Examiner-William F. Pate, III Attorney, Agent, or Firm-Richards, Harris & Medlock; Harold E. Meier [5 7] ABSTRACT An auxiliary safety door guard having a flexible retainer member formed into two loop portions, one of which carries a screw type fastener adapted to secure the guard to a door frame member. The other loop may be deflected and releasably engaged about the door knob to prevent unauthorized entrance by restriction of the door opening. A collar member is positioned on the guard to occupy the space presented to the door exterior when the door is slightly opened to shield the cable from being severed from the exterior. Plastic sheathing on the retainer adds to the appearance and facilitates engagement and disengagement of the retainer. A method of fabricating the door guard is also disclosed.

9 Claims, 6 Drawing Figures SAFETY DOOR GUARD This application is a continuation-in-part of application Ser. No. 106,497, entitled SAFETY DOOR GUARD, filed Jan. 14, 1971 and now abandoned.

The present invention relates to a safety door guard and a method of making the same. More specifically, the present invention relates to an auxiliary door latch device which can be secured around a conventional residential door knob to prevent unauthorized opening and entrance Almost all parts of the country have experienced an increase in crimes of the nature where a burglar or assailant forceably enters a residence or dwelling through a door. Conventional door latching devices and locks are easily picked or manipulated by a skilled burglar to gain entrance. Often, the burglar or assailant is admitted when the unwary homeowner opens the door to answer a knock at the door, In order to prevent such unauthorized, forceable entry, various devices have been suggested in the prior art. The most common of these devices is the chain night latch which is affixed to the interior of the door and door frame. This device consists of a chain which is secured at one end to the door frame. The opposite end of the chain is provided with a retainer which is erigagable within a slot in a receptacle secured to the door near its edge. To secure the latch, the owner simply inserts the fastener into the receptacle slot, thereby permitting the door to be opened a small distance. This permits the owner to crack the door to inspect the caller with the fastener in place. The chain, when taut, prevents the door from being forced open. i

There are several pronounced disadvantages to this type of security device. The most serious of these is that when the door is opened, the chain is exposed to the opening and an intruder can easily, with an appropriate metal cutting tool, shear the chain to gain entry. If the intruder is so disposed, violent entry can usually be made by simply applying sufficient force to the exterior of the door to tear out the relatively light screws from either the door or the door frame which secure the device. Obviously, the chain latch devices of the type described provide limited security to the occupants of a dwelling. More often than not, they give the dweller a false sense of security. Therefore, there is a demonstrated need for a security device for effectively preventing unauthorized entrance through the door of the dwelling, while permitting the occupant to open the door a limited distance to view the caller atthe door.

The present invention provides a security lock device which. has a flexible sheathed cable portion which is releasably engagable with the door knob. One end of the cable is secured by a substantial lag screw into the interior door frame. A collar is provided which serves as a shield and occupies a position in the normal door opening that prevents, without great difficulty, severing of the cable by a metal cutting tool. The device is sim ple, compact and does not noticeably detract from the appearance of the room interior. Further, the sheathing following specification, claims and drawings, in which:

FIG. 1 is an elevational view partly broken away, of the security chain of the present invention;

FIG. 2 is a partial detailed view of a portion of the chain shown in FIG. 1;

on the cable prevents scratching on the door knob and door escutcheon plate. The sheathing also serves to facilitate engagement and disengagement of the cable portion over the door knob.

A more complete understanding of the security chain of the present invention will become apparent from the FIG. 3 is a sectional view taken along lines 33 of FIG. 2;

FIG. 4 is an elevational view of a fragment of a door and door frame showing the safety security chain of the present invention in place;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 4; and

FIG. 6 is an elevational view of a portion of a door and door frame showing the security chain engaging a partially opened door to restrain further opening of the door.

Referring now to the drawings, particularly FIG. 1, the security device of the present invention is generally designated by the numeral 10 and includes a flexible restraining member 11 which is formed into a configuration having enlarged loop section 12 and adjacent small loop section 13. A generally cylindrical or elliptical shaped shield or collar 15 encircles member 11 to compress opposite sides of the flexible member together to form the loops. Larger loop 12 assumes a tear drop shape due to the compression at collar 15 diverging from the collar. A screw 18 secured to the smaller loop 13 with the flexible member extending through the opening 20 in the eye or head 119 of the screw. The relative size of the eye opening 20 permits easy movement of the bolt or loop 11 for installation of the fastener and engagement and disengagement of the device to the door knob.

The detailed construction of restraining member 11 is best shown in FIGS. 2 and 3. It will be seen that member 11 is comprised of an inner core member which is shown as flexible steel cable 14 having multiple helical wound strands. This type of cable is commonly known as airplane cable and is particularly adaptable as it is relatively light and flexible with high tensile and shear strength. The terminal ends 23 and 24 of the cable 20 are joined in abutting relationship. Preferably, the ends are joined by a tubular connector 21 which receives the ends and then is crimped by an appropriate tool to form a continuous member. Connector 211 is of relatively soft metal such as copper and is of a generally cylindrical configuration having a diameter adapted to facilitate insertion of the opposite ends 23 and 24 of the cable and sufficient length to provide ample surface engagement with the cable ends. The entire cable portion is sheathed or encased in a flexible plastic tubing 25. Typ ically, tubing 25 would be a vinyl or similar resin and may be suitably colored to give a pleasing decorative effect and to obscure the inner core of the cable from sight.

As seen in FIG. 3, shield 15 is in the form of a collar and is generally elliptically shaped and engages the restraining member 1 l in the area of the connector 21 to form opposite loops 12 and 13. Shield 15 is of a relatively high strength metal and is positioned on the retainer having sufficient length so as to occupy the area of the device 10 that would be exposed to the exterior when the device is engaged and the door opened a limited distance permitted by the device. To further give the unit a pleasing and decorative appearance, the

shield 15 and fastener 18 can both be plated with a light metallic coating of any desired material or color.

FIGS. 4, 5, and 6 best illustrate the installation and use of the present invention. Referring to these drawings, a door 30 is shown mounted in a casing 33 including conventional wooden structural members 34 such as 2 X 4'5. Exterior facing or door jamb 31 extends around the exterior of the door on the casing 33. A conventional door knob 40 having stem 41 for operating the locking bolt is mounted on the door. Escutcheon plate 38 may be secured to the door below the knob. The device of the present invention is secured in place by screwing thread 16 of screw fastener 18 well into interior casing member 34 at a location abutting frame 31. It will be noted that the screw 18 is of sufficient length to penetrate Well into the heavy frame members in order to give maximum security against forceable entry. Preferably, as is shown in FIG. 5, the shank of screw 18 will be angularly directed into the casing members 34 toward the door for maximum strength and resistance. With the chain device secured in this manner, the interior of loop 12 can be pushed over the knob 40, assuming a position around knob stops 41. As is seen in FIG. 6, the section of loop 12 most remote from the eye bolt closely aligns with the exterior surface of knob 40. Thus, some slight force may have to be applied to the loop to force it to laterally deflect to separate the opposite loop portion to allow loop 12 to ride across surface 42 of knob 40 to assume the position shown in FIG. 6, encircling the stem 41 of the knob. The smooth plastic sheathing 25 also serves to facilitate placing the loop about the knob as is shown. Once the loop is in place around the door, the loop will assume its original unexpanded shape as seen in FIG. 6 about the door knob stem.

The occupant may open the door a small distance to view a caller as is shown in FIG. 6. Loop 12 will engage stem 41 of the knob and present the door from being opened beyond this small distance. Since the opposite interior sides of loop 12 are spaced apart a distance less than the door knob diameter, the retainer cannot be ejected from the knob by shaking or rattling the door to gain entry. Should an attempt be made to forceably open the door, the restraining member 11 and lag bolt cooperating with the door knob will prevent such an attempt. Further, as is seen in FIG. 6, shield occupies a position so that no portion of the cable is presented to the person at the door exterior. Therefore, the cable cannot be reached without first cutting through the relatively heavy shield 15. Severing the shield would be most difficult and would not be accomplished with ordinary metal cutting tools without difficulty, which would normally give the occupants or neighbors time to take appropriate measures.

The design and construction of the novel security device described above also lends itself to efficient and economical fabrication. The materials of construction are all conventional and would be normally available. The manufacture of the device would proceed as follows:

Cable portion 14 would be severed by a cutting torch from a spool of conventional airplane cable to the desired length. for example, approximately l5 inches. Severing the desired length of cable from the supply roll by use of a torch is expedient and also serves to weld the frayed ends together to prevent unraveling of the strands of the cable. One end 23 of the cable is inserted into connector 21 to about half the depth of the connector. The connector is then crimped about the end 23 of the cable with a crimping tool. Sheathing 25 is cut from a piece of tubing to a length approximately equal to the length of the cable. The hollow sheath is then slipped axially along the cable until the sheath is coextensive with the interior core cable 20. Screw eye 19 is then slipped about the sheathed cable and the free end 24 of the cable is looped and inserted into the open end of connector 21. This end of the connector can then be crimped about end 23 of the cable. Since sheath 25 is flexible, this can easily be accomplished by applying pressure to the exterior of the sheathing 25. Although the cable ends could be welded, the crimping method is preferable as the heat generated in welding may cause deterioration of the plastic sheathing. The retainer, now in the form of a single continuous loop, is compressed together with opposite interior sides of the continuous loop placed in engagement. This permits shield 15 to be slipped onto the cable from the end opposite the lag bolt 18 and slid along the exterior of the cable until its desired position adjacent the bolt, thereby forming small loop 13 and large tear drop shaped loop 12. The device is complete and ready for installation in the manner described above.

From the above it can be seen that the present invention provides a security device which is highly effective to prevent unwanted intrusion into a dwelling. The device, when properly mounted, is firmly secured into the door frame members and therefore cannot be easily dislodged by the application of force to the exterior of the door. Furthermore, the design uses strong cable and the heavy metal shield, which cannot be easily cut from the door exterior to gain entrance. The device is easy to install and when installed is unobtrusive.

Although only a single embodiment of the invention is illustrated in the accompanying drawings described herein, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of rearrangement, modification, and substitution of parts and elements without departing from the spirit of the invention.

I claim:

1. A door guard adapted for use with a knob operated door positioned within a casing having a frame member adjacent the door edge, said guard comprising:

a flexible retainer configured to have a first loop of general teardrop shape adapted to deflect and fit over and engage a door knob and a second loop connected to said first loop at a neck section;

a fastener having a head portion encircling said second loop in a slidable association therewith and threadedly secured to the frame member; and

collar means engaging said retainer in the area of said neck whereby when said fastener is secured to said frame the first loop is releasably attached over the door knob to assume a position in the restricted opening presented to the exterior of the door.

2. The door guard as set forth in claim 1 including a flexible coating for sheathing the flexible retainer to provide a protective cover therefor.

3. The door guard as set forth in claim 1 wherein said retainer is formed from a length of flexible material configured into the first and second loops by joining the ends thereof in abutting relationship in the neck area between said loops.

4. The door guard as set forth in claim 3 wherein said collar means is secured about said retainer along the neck area shielding the connected ends of said retainer.

securing a fastener to said encased cable,

joining the free end of said cable to said connector to form a continuous loop, and

placing a collar around said continuous loop to form two smaller loops, one loop carrying said fastener and the other having a generally tear drop shape and adapted to deflect to engage a door knob. 7. The method of claim 6 wherein said cable is severed by a cutting torch and said flexible material comprises a plastic tubing which is drawn over the cable.

8. The method of claim 7 wherein said connector is crimped to said second cable end by applying force to the connector through the exterior of said tubing.

9. The method of claim 8 wherein said collar member is a generally elliptical and is adapted to be drawn along said sheathed cable when said cable is tightly compressed to form said two loops.

Patent Citations
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US502962 *Feb 23, 1893Aug 8, 1893 Herman green
US1891947 *Aug 8, 1929Dec 27, 1932Edward V PowellSupport for saxophones and similar musical instruments
US2151587 *Nov 2, 1938Mar 21, 1939Lee H CassilethDoor handle lock
US2904986 *Sep 5, 1958Sep 22, 1959Anderson Robert ASafety lock for refrigerators and the like
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3912314 *Jul 1, 1974Oct 14, 1975Sompayrac Hewitt ALocking device
US4022503 *Oct 16, 1975May 10, 1977Bey Henry APortable security lock
US4288119 *Jul 5, 1979Sep 8, 1981Air-Flo Co., Inc.Door locking cable
US4478442 *Sep 30, 1982Oct 23, 1984Martin Edward JSafety lock on entrance door
US4625705 *Mar 28, 1983Dec 2, 1986Willits William PBowstring release apparatus
US5716084 *Jul 31, 1996Feb 10, 1998Sanford, Jr.; Jack G.Door security system
US5908213 *Oct 7, 1996Jun 1, 1999Tippetts; David R.Elastic door locking device
US6155630 *May 28, 1999Dec 5, 2000Aisin Seiki Kabushiki KaishaSlide door device for automotive vehicles
US6863319 *Jan 27, 2003Mar 8, 2005James K. BentleySecurity door lock
U.S. Classification292/262, 29/433, 292/246, 29/517, 24/298
International ClassificationE05C17/36, E05C17/00
Cooperative ClassificationE05C17/365
European ClassificationE05C17/36B