US3901480A

US3901480A - Tamper-proof wire fabric fence clamps

Info

Publication number: US3901480A
Application number: US432358A
Authority: US
Inventors: Peter A Basile; Andrew Kolessar
Original assignee: Amerace Corp
Current assignee: Harvard Industries Inc
Priority date: 1974-01-10
Filing date: 1974-01-10
Publication date: 1975-08-26
Anticipated expiration: 1992-08-26

Abstract

A tamper-proof fence clamp adapted to affix a wire fabric material to tubular fence frame structures. The fence clamp is fabricated from a relatively thin elongated, normally U-shaped metal strap, which encircles the tubular fence structure and includes an oblique angled groove therein for accommodating a strand of the wire fabric. Hook-shaped portions provided on the terminal ends of the strap cooperatively engage each other and are bent towards a transverse ridge provided proximate one terminal end portion of the strap thereby locking the strap and affixing the strand of wire fabric to the tubular fence structure. An up-struck portion in the terminal end of the strap cooperatively engages a slot in the other terminal end portion of the strap to prevent lateral disengagement thereof.

Description

United States Patent Basile et al.

TAMPER-PROOF WIRE FABRIC FENCE CLAMPS Inventors: Peter A. Basile, Edison; Andrew Kolessar, Roselle Park, both of NJ.

Assignee: Amerace Corporation, New York,

Filed: Jan. 10, 1974 Appl. No.: 432,358

[52] US. Cl. 256/32; 24/73 SA; 24/81 CC; 24/259 C; 24/255 SL [51] Int. Cl. A44B 21/00 [58] Field of Search 256/34, 47, 48, 32; 24/20 CW, 20 W, 81 CR, 81 BA, 20 T1", 73 SA, 81 CC, 255 SL, 259 C [56] References Cited UNITED STATES PATENTS l,63l,396 6/1927 Beegle 24/20 CW 2,968,470 l/l967 Pellerito et al. 256/47 3,021,114 2/1962 OConnell 256/47 X 3,082,498 3/1963 Oetiker 24/20 CW 3,370,l22 2/1968 lchikawa 24/20 TT X Primary ExaminerDennis L. Taylor Attorney, Agent, or Firm-S. Michael Bender; R. A.

Craig; Martin Sachs [5 7 ABSTRACT A tamper-proof fence clamp adapted to affix a wire fabric material to tubular fence frame structures. The fence clamp is fabricated from a relatively thin elongated, normally U-shaped metal strap, which encircles the tubular fence structure and includes an oblique angled groove therein for accommodating a strand of the wire fabric. Hook-shaped portions provided on the terminal ends of the strap cooperatively engage each other and are bent towards a transverse ridge provided proximate one terminal end portion of the strap thereby locking the strap and affixing the strand of wire fabric to the tubular fence structure. An upstruck portion in the terminal end of the strap cooperatively engages a slot in the other terminal end portion of the strap to prevent lateral disengagement thereof.

15 Claims, 8 Drawing Figures PATENTEI] AUG 26 1975 SHEET 1 n5 2 Figure l PATENTED Auszsms SKEZT 2 BF 2 TAMPER-PROOF WIRE FABRIC FENCE CLAMPS BACKGROUND OF THE INVENTION The present invention relates generally to fence clamps, and more particularly, to a wire fabric fence clamp which is easily installed and tamper-proof thereafter.

Present day manufacturers of wire fabric security fences use machine-formed wire ties to secure the fence fabric to the fence frame structure. The conventional wire tie is merely a length of wire wrapped around the fence rail and fabric with closure being accomplished by twisting the wire ends around each other. Recently, increased incidents of vandalism in which the tie wires have been cut, broken or unwound have created a need for a more secure and tamperproof means of accomplishing fence fabric tie down.

Accordingly, it is an object of the present invention to overcome the shortcomings of prior art tie down devices by providing a tamper-proof wire fabric fence clamp which may readily and rapidly be installed with the aid ofa hand tool especially adapted to perform this function.

Another object of the present invention is to provide a tamper-proof wire fabric clamp that is relatively inexpensive to manufacture and install.

Briefly summarized, the tamper-proof clamp for affixing wire fabric material to fence frame structures, according to the principles of the present invention, comprises an elongated strap having a longitudinal axis, the elongated strap normally being generally U-shaped and having a base portion and first and second arm portions. A groove, substantially centrally disposed within the base portion, opens inwardly, and extends across the strap'at an oblique angle relative to the longitudinal axis thereof. The free end of the first arm portion is inwardly bent at the terminal end thereof to form a first hook-shaped portion. The free end of thesecond arm portion is outwardly bent at the terminal end thereof to form a second hook-shaped portion. An outwardly facing ridge extends transversely across the strap proximate the second hook-shaped portion. The first and second hook-shaped portions are adapted to be displaced towards each other for cooperative engagement when the strap is disposed about the frame structure with the wire fabric being retained in the groove to fixedly secure the wire fabric material to the fence structure. The cooperatively engaged hook-shaped portions are adapted for bending displacement towards the outwardly facing ridge until flush therewith.

Other objects and features of the present invention will become more apparent from the following descriptions made with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a pictorial representation of a wire fabric fence with which the present invention may be employed;

FIG. 2 is a fragmentary view on an enlarged scale as indicated by the area within the broken line 2 in FIG.

FIG. 3 is an end view in elevation of the area shown in FIG. 2 illustrating the configuration of the clamp when completely installed;

FIG. 4 is an enlarged pictorial representation in perspective of the wire fabric fence clamp in accordance with the principles of the present invention;

FIG. 5 is an end view in elevation of the clamp shown in FIG. 4 illustrating the cooperation of the terminal ends of the clamp with the upper and lower jaws of a hand tool suited for the installation thereof;

FIG. 6 is an end view in elevation of the fence clamp shown in FIG. 4 in the process of having the terminal end hook portions cooperatively engaged by a hand tool therefor;

FIG. 7 is an end view in elevation of the fence clamp shown in FIG. 4 with the cooperatively engaged portions thereof being hammered into position; and

FIG. 8 is an enlarged fragmentary cross-sectional view in elevation of an installed fence clamp taken along the line 8-8 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, and initially to FIG. 1, there is shown a pictorial representation of a wire fabric security fence generally designated by reference numeral 10. The security fence 10 includes horizontally and vertically positioned tubular-shaped fence frame structures 12; extending bracket portions 14, which are adapted to support thereon barbed wire 16 in a conventional manner; and wire fabric material 18, which is affixed to the tubular fence frame structures 12 by means of a plurality of tamper-proof wire fabric fence clamps 20 constructed in accordance with the present invention.

As shown in more detail in FIGS. 2 and 3, individual strands 30 of the wire fabric material 18 are adapted to be held in intimate contact with a tubular fence post or structure 12 by the snug fitting fence clamp 20 with each clamp 20 providing a shallow silhouette so that it is impervious to attack by conventional hand tools frequently used by vandals.

Althoughthe preferred embodiment of the present invention is illustrated showing tubular-shaped fence frame structures and circular-shaped wire strands 30 which form the wire fabric fence material, it is to be understood that the principles set forth herein apply equally as well to fence structures and wire fabric material manufactured with other configurations.

Tuming now to FIG. 4, each clamp 20 is preferably manufactured from a relatively thin, elongated, narrow stainless steel strap formed in a generally U-shaped configuration. Alternatively, a vinyl-covered metallic material may be used to fabricate the clamp 20 so as to provide the same non-corrosive advantages as that provided by the stainless steel strap material.

The normally U-shaped clamp 20 which has a longitudinal extent approximately equal to the circumference of the tubular fence structure with which it is to be employed, includes a base portion 22 and two oppositely disposed

arm portions

24 and 26. The base portion 22 has an inside radius of curvature substantially equal to the outer radius of curvature of the tubular fence structure and includes a substantially centrally located groove 28 which opens inwardly with respect to the U-shape of the clamp 20 and is adapted to retain therein a strand (single wire) 30 of the wire fabric material. The inside radius of curvature of the groove 28 should be approximately the same as the radius of curvature of the wire strand 30 but is preferably made slightly smaller than the radius of curvature of the strand to more tightly retain the strand therein when the clamp is installed. In the preferred embodiment of the invention, the groove 28 is formed at an oblique angle relative to the longitudinal axis of the strap as most clearly seen in FIGS. 2 and 4. This is done inasmuch as conventional wire fabric fence material, commonly referred to as chain link, is usually fabricated from wire stands which are interwoven and linked together to form generally diamond-shaped apertures (see FIG. 2) i.e., the strands criss-cross the fence support structures at approximately a 45 angle with reference to the longitudinal axis of each fence frame structure. Thus, when strands of the wire fabric fence material are oriented at an oblique angle with respect to a horizontal or vertical fence frame structure or support post, the obliquely oriented groove 28 enables the fence clamp to accommodate the similarly obliquely oriented wire strands 30 and securely affix the wire fabric material to either horizontally or vertically oriented fence frame structures 12 as the case may be.

In this regard, however, it will be noted that for a given fence fabric material it may be necessary to displace by approximately 90 the axis of the oblique groove in a fence clamp used with a horizontal fence structure as compared to the orientation of the axis of the oblique groove in a fence clamp used with a vertical fence structure. Of course, it will be appreciated that when the strands of the fabric fence material are oriented at angles other than oblique with respect to the longitudinal axis of the fence frame support structure or post to which they are to be affixed, the groove 28 may be oriented in a corresponding manner relative to the longitudinal axis of the strap, e.g., the axis of groove 28 may be oriented at a right angle relative to the longitudinal axis of the strap when the fence fabric material comprises wire strands oriented parallel and perpendicular to the fence frame support structure or post.

It will be noted further that during the fabrication of a fence clamp including a groove 28 in the base portion 22 oriented at an oblique angle relative to the longitudinal axis of the strap, an offset 32 (FIG. 2) is advantageously introduced into the base portion in order to prevent shearing of the strap. Thus, the

arm portions

24, 26 of clamp 20 will not be positioned in the same plane when the clamp is normally disposed as shown, for example, in FIG. 4. The ramifications of the

offset arm portions

24, 26 will become apparent hereinafter.

The free end of the first arm portion 24 is inwardly bent along a first transverse crease line 35 to form a first hook-shaped portion 34 at the terminal end of the first arm portion 24. The first hook-shaped portion 34, in turn, includes a first section 34a and a second section 34b disposed on either side of the transverse crease line 35, respectively. Preferably, the first section 34a of the hook-shaped portion 34 is bent slightly inwardly with respect to arm portion 24 along a second crease line 37 to define a slightly inwardly extending inclination to section 34a. First and

second crease lines

35, 37 coincide with a corresponding pair of

transverse bending axes

39, 41 the purpose of which will be more fully explained below. In addition, an aperture or perforation 38 is provided in the first arm portion 24 proximate the first section 34a of the hook-shaped portion 34 as clearly shown in FIG. 4, and a protruding or up-stuck portion 40 is provided in the upper surface of the second section 34b of the hook-shaped portion 34 as viewed in FIG. 4. The up-struck portion 40 is preferably located substantially centrally with respect to the transverse extent of the second section 34b and may be provided therein by a conventional coining process. The respective functions of the aperture 38 and upstruck portion 40 will be explained hereinafter.

The free end of the second arm portion 26 is outwardly bent along a third crease line 45 to form a second hook-shaped portion 42 at the terminal end thereof having a first section 420 and a second section 42b disposed on opposite sides of the crease line 45, respectively. The third crease line 45 coincides with a corresponding transverse bending axis 47 the function of which will be discussed more fully below. Proximately located with respect to the first section 42a of the second hook-shaped portion 42 is an outwardly protruding ridge 44 extending transversely across the width of the second arm portion 26 and having a height with reference to the outer surface of second arm portion 26 at least as great as the combined thickness of

sections

34a, 34b, and 42b. This outwardly protruding transversely extending ridge 44 may preferably be provided in the second arm portion 26 by forming a transverse groove therein opening inwardly with respect to the U-shaped clamp 20. Finally, a cut-out or slot 46 is provided in the second section 42b of the second hookshaped portion 42 substantially as shown in FIG. 4, that is, with the slot opening in the outer free edge of the second section 42b and having its rearward extent terminating substantially at the third crease line 45. The cut-out 46 is sized and shaped sufficiently to receive the up-struck portion 40 on the first hook-shaped portion 34 for reasons which will be made more apparent in the ensuing discussion.

In order to install the wire fence clamp 20 of the present invention, either

arm

24, 26 may be outwardly flexed relative to the other arm and the clamp may then be inserted through a pair of adjacent apertures or openings 48 provided in the wire fabric material until a wire strand 30 is accommodated within oblique angled groove 28 and the first (upper) and second (lower)

arm portions

24 and 26 of the clamp 20 respectively, surround the tubular fence frame structure 12 as shown in FIG. 5. The

arm portions

24 and 26 of the U- shaped clamp are normally inwardly directed toward each other so that the spacing 50 between the terminal portions of these arm portions is smaller than the diameter of the fence frame structure 12 thereby tending to hold the wire fabric material 18 to the fence frame structure 12 in the position generally shown in FIG. 5.

While it will be apparent that a variety of conventional hand tools may be used to install the clamp 20 a plier-type hand tool 52 especially adapted for this purpose and having an upperjaw 54 and a lower jaw 55 may preferably be used to complete the installation of the clamp 20. For a more complete disclosure of the hand tool 52 reference may be had to copending patent application entitled Hand Tool For Installing Wire Fabric Fence Clamps," Ser. No. 432,357, filed Jan. 10, 1974 in the name of P. A. Basile, and assigned to the same assignee as the present invention. It will be sufficient for a full understanding of the present invention to appreciate that the upper jaw 54 of the hand tool is relatively narrow and is provided with an elongated projection 58 (FIG. 7) adapted to fit into and engage the first arm portion 24 through aperture 38 as at reference numeral 60 (FIG. 4); and that the lower jaw 56 of the hand tool 52 preferably is provided with a transversely extending edge 62 which has a protrusion 64 adapted to cooperatively engage cut-out 46 provided in the second section 42a of the second hook-shaped portion 42 of arm portion 26. Accordingly, movement of the upper and

lower jaws

54, 56 of the hand tool toward each other causes corresponding displacement toward each other of the first and second hook-shaped

portions

34, 42 until the hook formed by

sections

34a and 34b of the first hook-shaped portion 34 cooperatively engages the second section 42b of the second hook-shaped portion 42 as shown in FIG. 6. Additionally, as the first and second hook-shaped

portions

34, 42 are displaced toward each other by the closing action of the

tool jaws

54, 56 they are pulled into the same plane for cooperative engagement thereby overcoming the offset 32 caused by the provision of the oblique groove 28, as mentioned earlier. Once the first and second hook-shaped

portions

34, 42 have become engaged the hand tool may then be removed.

The outer peripheral surface of the lower jaw 56 of hand tool 52 is preferably provided with a flat portion 66 suitable for hammering. Accordingly, this hammering surface 66 may then be used to bend the cooperatively engaged hook-shaped

portions

34 and 42 towards the transverse ridge 44 as shown in FIG. 7 to complete installation of the clamp 20. Thus, a few blows of the hammering surface 66 against the inclined section 34a of the first hook-shaped portion 34 will cause bending of the second section 34b relative to the first section 34a about the second transverse bending axis 39; and bending of the second section 42b of the second hook-shaped portion 26 relative to the latters first section 42a about the third transverse bending axis 47 until the

various sections

34a, 34b, and 42b are disposed substantially parallel to section 42a and the outer surface of section 34a lies substantially flush with respect to the protruding transversely extending ridge 44 provided adjacent section 42a on second arm portion 26. In this manner, the sharply rounded edge defined by the second crease line 35 of the first hook-shaped portion will abut up against and be protected by the ridge 44 whereupon subsequent unauthorized attempts to open the clamp by the insertion of a sharp blade (e.g., a screwdriver blade) underneath the second section 34b will be prevented.

It is also to be noted with reference to FIG. 8 that the up-struck portion 40 provided in the second section 34b of the first hook-shaped portion 34 will cooperatively engage the cut-out 46 provided in the second section 42b of the second hook-shaped portion 42, thereby preventing relative vertical displacement (as viewed in FIG. 8) between the first and

second arm portions

24, 26 of clamp when struck by a vandals tool. Accordingly, a vandal will be unable to remove the tamperproof fabric fence clamp from the fabric side of the fence. Removal of the clamp from the frame structure side of the fence is equally difficult.

It thus will be appreciated that the present invention discloses a wire fabric fence clamp that is relatively inexpensive to manufacture, easy to install, and virtually tamper-proof when installed.

Having thus set forth the nature of the invention what is claimed is:

1. A tamper-proof clamp for affixing wire fabric material to a fence frame structure, comprising: an elongated strap, said strap normally being generally U- shaped and having a base portion and first and second arm portions extending outwardly therefrom, a groove substantially centrally disposed within said base portion, said groove opening inwardly and extending across the width of said strap, the free end of said fist arm portion being inwardly bent at the terminal end thereof to form a first hook-shaped portion, said first hook-shaped portion including an up-struck portion extending inwardly thereof, the free end of said second arm portion being outwardly bent at the terminal end thereof to form a second hook-shaped portion, said second hook-shaped portion including an aperture therein for enabling said second hook-shaped portion to engage the up-struck portion of said first book shaped portion, an outwardly facing ridge extending transversely with respect to said strap proximate said second hook-shaped portion, said first and second hook-shaped portions being adapted to be displaced towards each other for cooperative engagement with said up-struck portion in said first hook-shaped portion being received within said aperture in said second hook-shaped portion when said strap is disposed about said frame structure with said wire fabric being retained in said groove to affix said wire fabric material to said frame structure, said cooperatively engaged first and second hook-shaped portions being adapted for common bending displacement toward said outwardly facing ridge until flush therewith.

2. A tamper-proof clamp for affixing wire fabric material to fence structures according to claim 1 wherein the height of said outwardly facing transverse ridge is at least as great as the combined thickness of said cooperatively engaged hook-shaped portions after bending displacement thereof.

3. A tamper-proof clamp for affixing wire fabric material to fence structures according to claim 1 wherein a second aperture is provided in said first arm portion proximate said first hook-shaped portion, said second aperture and said second hook-shaped portion being adapted to cooperate with means for fixedly securing said strap about said wire fabric and said frame structure.

4. A tamper-proof clamp according to claim 1 wherein said fence frame structure is tubular-shaped and said strap base portion is arcuate-shaped and has an inside radius of curvature approximately equal to that of said tubular-shaped fence structure.

5. A tamper-proof fence clamp according to claim 1 wherein said inwardly opening groove has an inside radius of curvature substantially equal to the radius of curvature of a strand of ,said wire fabric material.

6. A tamper-proof fence clamp according to claim 1 wherein said inwardly opening groove has an inside radius of curvature slightly smaller than the radius of curvature of a strand of said wire fabric material.

7. A tamper-proof fence clamp according to claim 1 wherein said fence clamp comprises stainless steel.

8. A tamper-proof fence clamp according to claim 1 wherein said fence clamp comprises vinyl-covered metallic material.

9. A tamper-proof fence clamp according to claim 1 wherein said angle is oblique.

10. A tamper-proof clamp for affixing wire fabric material to a fence frame structure comprising: an elongated strap, said strap normally being generally U- shaped and having a base portion and first and second arm portions extending outwardly therefrom, a groove substantially centrally disposed within said base portion, said groove opening inwardly and extending across the width of said strap, the free end of said first arm portion being inwardly bent at the terminal end thereof to form a first hook-shaped portion, the free end of said second arm portion being outwardly bent at the terminal end thereof to form a second hook-shaped portion, an outwardly facing ridge extending transversely with respect to said strap proximate said second hook-shaped portion, said first and second hookshaped portions being adapted to be displaced towards each other for cooperative engagement with each other when said strap is disposed about said frame structure with one of the strands of said fabric material being retained in said groove to affix said fabric material to said frame structure, said cooperatively engaged hookshaped portions being adapted for common bending displacement towards said outwardly facing ridge until flush therewith.

11. A tamper-proof fence clamp according to claim 10 wherein said first hook-shaped portion includes a first section and a second section disposed on either side of a transverse crease line, said first section being bent inwardly with respect to said first arm portion along a second transverse crease line, said second section including an up-struck portion, said second hookshaped portion including a first section and a second section disposed on either side of a third transverse crease line, said second section including a aperture adapted to receive said up-struck portion, said first, second and third transverse crease lines being essentiaily parallel to each other.

12. A tamper-proof fence clamp according to claim 11 wherein the height of said outwardly facing transverse ridge is at least as great as the combined thickness of said first and second sections of said first hookshaped portion and said second section of said second hook-shaped portion.

13. A tamper-proof clamp for affixing wire fabric material to a fence frame structure comprising: an elongated strap, said strap normally being generally U- shaped and having a base portion and first second arm portions extending outwardly therefrom, a groove substantially centrally disposed within said base portion,

said groove opening inwardly and extending across the width of said strap, the free end of said first arm portion being inwardly bent at the terminal end thereof to form a first hook-shaped portion, said first hook-shaped portion including an up-struck portion extending inwardly thereof, the free end of said second arm portion being outwardly bent at the terminal end thereof to form a second hook-shaped portion, said second hook-shaped portion including an aperture for enabling said second hook-shaped portion to engage the up-struck portion of said first hook-shaped portion, said first and second hook-shaped portions being adapted to be displaced towards each other for cooperative engagement with said up-struck portion in said first hook-shaped portion being received within said aperture in said hook-shaped portion when said strap is disposed about said frame structure with one of the strands of said fabric material being retained in said groove to affix said fabric material to said frame structure, said cooperatively engaged first and second hook-shaped portions being adapted for common bending displacement toward the outer surface of said second arm portion.

14. A clamp according to claim 13 wherein the first hook-shaped portion of said clamp includes a first section and a second section disposed on either side of a transverse crease line, said first section being bent inwardly with respect to said first arm portion along a second transverse crease line, said second section including the up-struck portion, said second hook-shaped portion including a first section and a second section disposed on either side of a third transverse crease line, said second section in said second hook-shaped portion including said aperture enabling said second hookshaped portion to engage said up-struck portion, said first, second and third transverse crease lines being essentially parallel to each other.

15. A clamp according to claim 14 wherein said clamp includes an outwardly facing ridge extending transversely with respect to said strap proximate said second hook-shaped portion and wherein said cooperatively engaged hook-shaped portions are adapted for common bending displacement toward said outwardly facing ridge until flush therewith.

Claims

1. A tamper-proof clamp for affixing wire fabric material to a fence frame structure, comprising: an elongated strap, said strap normally being generally U-shaped and having a base portion and first and second arm portions extending outwardly therefrom, a groove substantially centrally disposed within said base portion, said groove opening inwardly and extending across the width of said strap, the free end of said fist arm portion being inwardly bent at the terminal end thereof to form a first hook-shaped portion, said first hook-shaped portion including an up-struck portion extending inwardly thereof, the free end of said second arm portion being outwardly bent at the terminal end thereof to form a second hook-shaped portion, said second hook-shaped portion including an aperture therein for enabling said second hook-shaped portion to engage the up-struck portion of said first hook-shaped portion, an outwardly facing ridge extending transversely with respect to said strap proximate said second hook-shaped portion, said first and second hook-shaped portions being adapted to be displaced towards each other for cooperative engagement with said up-struck portion in said first hook-shaped portion being received within said aperture in said second hookshaped portion when said strap is disposed about said frame structure witH said wire fabric being retained in said groove to affix said wire fabric material to said frame structure, said cooperatively engaged first and second hook-shaped portions being adapted for common bending displacement toward said outwardly facing ridge until flush therewith.

5. A tamper-proof fence clamp according to claim 1 wherein said inwardly opening groove has an inside radius of curvature substantially equal to the radius of curvature of a strand of said wire fabric material.

10. A tamper-proof clamp for affixing wire fabric material to a fence frame structure comprising: an elongated strap, said strap normally being generally U-shaped and having a base portion and first and second arm portions extending outwardly therefrom, a groove substantially centrally disposed within said base portion, said groove opening inwardly and extending across the width of said strap, the free end of said first arm portion being inwardly bent at the terminal end thereof to form a first hook-shaped portion, the free end of said second arm portion being outwardly bent at the terminal end thereof to form a second hook-shaped portion, an outwardly facing ridge extending transversely with respect to said strap proximate said second hook-shaped portion, said first and second hook-shaped portions being adapted to be displaced towards each other for cooperative engagement with each other when said strap is disposed about said frame structure with one of the strands of said fabric material being retained in said groove to affix said fabric material to said frame structure, said cooperatively engaged hook-shaped portions being adapted for common bending displacement towards said outwardly facing ridge until flush therewith.

11. A tamper-proof fence clamp according to claim 10 wherein said first hook-shaped portion includes a first section and a second section disposed on either side of a transverse crease line, said first section being bent inwardly with respect to said first arm portion along a second transverse crease line, said second section including an up-struck portion, said second hook-shaped portion including a first section and a second section disposed on either side of a third transverse crease line, said second section including a aperture adapted to receive said up-struck portion, said first, second and third transverse crease lines being essentially parallel to each other.

12. A tamper-proof fence clamp according to claim 11 wherein the height of said outwardly facing transverse ridge is at least as great as the combined tHickness of said first and second sections of said first hook-shaped portion and said second section of said second hook-shaped portion.

13. A tamper-proof clamp for affixing wire fabric material to a fence frame structure comprising: an elongated strap, said strap normally being generally U-shaped and having a base portion and first second arm portions extending outwardly therefrom, a groove substantially centrally disposed within said base portion, said groove opening inwardly and extending across the width of said strap, the free end of said first arm portion being inwardly bent at the terminal end thereof to form a first hook-shaped portion, said first hook-shaped portion including an up-struck portion extending inwardly thereof, the free end of said second arm portion being outwardly bent at the terminal end thereof to form a second hook-shaped portion, said second hook-shaped portion including an aperture for enabling said second hook-shaped portion to engage the up-struck portion of said first hook-shaped portion, said first and second hook-shaped portions being adapted to be displaced towards each other for cooperative engagement with said up-struck portion in said first hook-shaped portion being received within said aperture in said hook-shaped portion when said strap is disposed about said frame structure with one of the strands of said fabric material being retained in said groove to affix said fabric material to said frame structure, said cooperatively engaged first and second hook-shaped portions being adapted for common bending displacement toward the outer surface of said second arm portion.

14. A clamp according to claim 13 wherein the first hook-shaped portion of said clamp includes a first section and a second section disposed on either side of a transverse crease line, said first section being bent inwardly with respect to said first arm portion along a second transverse crease line, said second section including the up-struck portion, said second hook-shaped portion including a first section and a second section disposed on either side of a third transverse crease line, said second section in said second hook-shaped portion including said aperture enabling said second hook-shaped portion to engage said up-struck portion, said first, second and third transverse crease lines being essentially parallel to each other.