US3857416A

US3857416A - Hinge for hinged stirrup fabric

Info

Publication number: US3857416A
Application number: US00381694A
Authority: US
Inventors: D Borodin; M Henry
Original assignee: New York Wire Mills Corp
Current assignee: New York Wire Mills Corp
Priority date: 1973-07-23
Filing date: 1973-07-23
Publication date: 1974-12-31
Anticipated expiration: 1991-12-31
Also published as: ATA601974A; CA1009165A; FR2238568A2; DE2435374A1; FR2238568B2; AT334049B

Abstract

A fabric for reinforcing concrete pipe and the like wherein stirrup members for anchoring the fabric in the pipe are hingedly secured to the fabric via hinge members which allow rotation of the stirrup members between a non-erect position generally parallel to the fabric and an erect position generally perpendicular to the fabric. The hinge members include various forms of yieldable restraining means which selectively bias the stirrup members either into both the non-erect and erect positions or into only the non-erect position. Additional means in various forms are included for retaining the stirrup members in the erect position and for preventing further rotation thereof from that position.

Description

[451 Dec. 31, 1974 United States Patent [191 Borodin et a1.

[ HINGE FOR HINGED STIRRUP FABRIC Primary ExaminerJerry W. Myracle Attorney, Agent, or Firm-Price, Heneveld, l-luizenga & Cooper [75] Inventors: Daniel J. Borodin; Mort W. Henry,

both of Detroit, Mich.

[57] ABSTRACT A fabric for reinforcing concrete pipe and the like [22] Filed:

wherein stirrup members for anchoring the fabric in the pipe are hingedly secured to the fabric via hinge members which allow rotation of the stirrup members between a non-erect position generally parallel to the fabric and an erect position generally perpendicular to the fabric. The hinge members include various forms [52] US. 138/175 F161 9/08 138/175; 245/2; 140/921 [51] Int.

[58] Field of Search......... of yieldable restraining means which selectively bias the stirrup members either into both the non-erect and erect positions or into only the non-erect position. Ad- References cued ditional means in various forms are included for re- UNITED STATES PATENTS taining the stirrup members in the erect position and for preventing further rotation thereof from that position.

2,227,153 12/1940 Prosser....... ...................138/175X 3,411,544 11/1968 Keyser................................ 138/175 28 Claims, 12 Drawing Figures PATENTEI] HERB] I974 sum 1 or 5 FIGJ PATENTEI] UECBI i974 SHEET 2 BF 5 PATENTEDHEB31 1974 I saw 30F 5 PATENTEU [IE-C31 I974 saw u or 5 HINGE FOR I-IINGED STIRRUP FABRIC This invention relates to fabric for reinforcing concrete pipe and the like, and, more particularly, to means for hingedly securing projecting stirrup members to the reinforcing fabric.

BACKGROUND OF THE INVENTION Pipes and other products made from concrete are generally reinforced with a fabric framework made from steel wire or other rigid materials. The reinforcing fabric is enclosed within the concrete when the final product is formed. Frequently, the fabric includes projecting stirrup members which further anchor the fabric in the concrete. Recent advances have occured in the reinforcing fabric industry wherein stirrup members including a plurality of projections are hingedly secured to the fabric as opposed to being laboriously and individually welded or otherwise secured to the fabric. Accordingly, as described in copending application, Ser. No. 300,114, entitledSTIRRUPFABRIC AND METHOD FOR FORMING PIPE REINFORCE- MENT, invented by Wilbur E. Tolliver, filed Oct. 24,

1972, and assigned to the same assignee as the present invention, the disclosure of which is incorported by reference herein, the projecting stirrup members of the present invention are hingedly secured whereby the remain generally parallelto the remainder of the fabric during transportation and any rollforming of the fabric, but may be rotated toremain in the erect, anchoring position immediately prior to the pouringof concrete.

Advances have also been made recently in the means for hingedly securing the stirrup members to the reinforcing fabric. In copending application NYWM P-3 l 3, Ser. No. 381,478, entitled HINGE FOR HINGED STIRRUP FABRIC, invented by Daniel J. Borodin and Mort W. Henry, filed on even date herewith and assigned to the same assignee as the present invention, the disclosure of which is incorporated by reference herein, the hinge means disclosed and claimed include means for maintaining the stirrup members and projections in their non-erect, parallel positions in order to facilitate storage and transportation as well as to pre vent damage to any roll forming machinery which could occur if the projection became erected during such forming. Further, the hinge means include means for maintaining the stirrup members in their erect position such that the members remain erect during the pouring of concrete to accomplish their anchoring function.

However, further stabilization of the stirrup members in both their non-erect. generally parallel positions as well as their erect, generally perpendicular positions would be desirable in order to facilitate the operation of the hinged stirrup fabric in the manner described above. Further, it would be desirable to simplify the manufacture and operation of the hinge as well as their installation on the reinforcing fabric.

SUMMARY OF THE INVENTION The present invention provides a hinge means for hingedly securing stirrup members to a fabric for reinforcing concrete pipes and the like, the hinge means including yieldable restraining means connected to the stirrup member. In one form, the yieldable restraining means stabilize the stirrup members in both the nonerect position generally parallel to the reinforcing fabric as well as in the erect position at generally normal to the reinforcing fabric. In another form, the yieldable restraining means stabilize the stirrup members in only the non-erected position. In another aspect of the invention, the specific hinge means includes a simplified means for capturing a portion of the stirrup member when the member is in its erected position such that the stirrup member is retained in that position and prevented from any further rotation from that position.

As the stirrup projection is rotated about the hinge axis to its erect position, the yieldable restraining means gradually stretches or expands. Expansion means comprising an integral expansion loop or alternating slots spaced along either side of the yieldable restraining means may be included to accommodate the expansion of the restraining means. In this form, the yieldable restraining means remains intact when the stirrup member reaches the erect position and biases and retains the member in the erect position. Alternatively, the yieldable restraining means includes no integral expansion means but rather stretches to a certain point and may subsequently fracture as the stirrup member reaches the erect position. In this form, the restraining means may or may not provide a biasing means for the stirrup member in the erect position.

In another form of the invention, the yieldable restraining means comprises an arm extending from the base of the hinge member. In this form, the arm is secured to a tie rod to which a plurality of stirrup projections are joined. The yieldable restraining arm resists any rotation of the tie rod, thereby holding the stirrup member in the non-erect position. As sufficient force is applied to rotate the stirrup member to the erect position, however, the arm stretches allowing rotation of the tie rod. This yieldable restraining arm may or may not include integral expansion means as described above.

The hinge member of the invention may also include capturing means which retain the stirrup members in the erect position and resist any further rotation thereof. In one form. a stirrup projection is captured in the erect position via a stop arm extending from the base of the hinge member and an opposing abutting shoulder.

These and other objects, advantages, purposes, and features of the invention will become apparent from a study of the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a concrete pipe including a fabric reinforcing cage having hinged stirrup projections rotated to their erect position;

FIG. 2 is a cross-sectional view of a concrete pipe including a fabric reinforcing cage and separate fabric mats secured thereto, the mats including hinged stirrup members rotated to their erect position;

FIG. 3 is a perspective view of a portion of the reinforcing fabric including stirrup members hingedly secured thereto via one form of the hinge means of the present invention, the stirrup members being shown in the non-erect position;

FIG. 4 is a perspective view of the reinforcing fabric shown in FIG. 3, the stirrup members being shown in the erect position;

FIG. 5 is an enlarged perspective view of a portion of the reinforcing fabric shown in FIG. 3, with the hinge member thereof biasing the stirrup member to the nonerect position;

FIG. 6 is an enlarged perspective view of a portion of the reinforcing fabric shown in FIG. 3 or FIG. 4 with the hinge member locking the stirrup member into the erect position;

FIG. 7 is an end view of the hinge member taken along plane VII-VII of FIG. 6;

FIG. 8 is a cross sectional view taken along plane VIIl-VIII of FIG. 5;

FIG. 9 is a cross sectional view taken along plane lX-IX of FIG. 6;

FIG. 10 is a cross-sectional view taken along plane X-X of FIG. 5, the reinforcing fabric including the stirrup member shown after a forming operation;

FIG. 11 is an enlarged, perspective view of a hinge member similar to those shown in FIGS. 3-10, but including another form of the yieldable restraining means; and

FIG. 12 is an enlarged, perspective view of another embodiment of the hinge member including yet another form of the yieldable restraining means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first prefered embodiment, hinge member 40 includes a yieldable restraining member 50 secured to stirrup member 28 (FIG. 5). Because it is fairly stiff, it holds stirrup member 28 in its non-erected position. When a rotating force is applied to stirrup member 28, the restraining force of yieldable restraining member 50 is overcome and yieldable restraining member 50 yields. An integral loop 56 allows expansion of yieldable restraining member 50 without fracture (FIG. 7).. Thus when stirrup member 28 is rotated to its erect position, yieldable restraining member 50 tends to rigidify and hold stirrup member 28 in that position.

Stirrup member 28 is further held in its erect position by an arm 60 and a shoulder 66, both integral with hinge 40. When stirrup member 28 is erected, the bottom of one of its stirrup projections 32 abuts shoulder 66 on one side and the end of arm 60 on the other and is thereby trapped in its erected position.

As shown in FIGS. 3 and 4, the reinforcing fabric of the type inserted in pipes 10 and 12 (FIGS. 1 8L 2) typically comprises a plurality of criss-crossed wire strands including longitudinally extending strands 24 as well as circumferentially extending strands 26. Longitudinal strands 24 extend generally normally to the pipe crosssections shown in FIGS. 1 and 2, while circumferential strands 26 extend generally parallel to the plane of the pipe cross-sections and are the strands which are roll formed into the elliptical shape. As described in copending application Ser. No. 300,1 14, mentioned above and incorporated by reference herein, a plurality of stirrup members 28 for anchoring the reinforcing fabric in the concrete are hingedly secured generally parallel to the longitudinal strands 24. Although the stirrup members may be of many varied shapes as described in the copending application, typically, the stirrup members are as shown in FIGS. 3 and 4. These comprise an elongated tie rod 30 and a plurality of stirrup projections or rods 32 which are secured via welding or the like generally perpendicularly to the axis of the tie rod. When hinged via the hinges of the present invention and/or those of the copending applications mentioned above, the stirrup members are rotatable about hinge axes comprising the axes of the tie rod 30 from a non-erect position shown in FIG. 3, wherein the stirrup projections 32 are generally parallel to the remainder of the fabric, and an erect position shown in FIG. 4, wherein the projections extend generally normally to the remainder of the fabric.

Referring now to FIGS. 3, 5, 8 and 10, a first embodiment 40 of the hinge member is shown hingedly securing the stirrup members 28 to the reinforcing fabric and holding the stirrup projections in the non-erect posi tion.

The entire hinge member 40 is stamped or otherwise formed from mild, annealed steel or other similar rigid material. Such steel or similar materials include some inherent resiliency providing spring-like tendencies for the hinge. Hinge member 40 includes a base 42 having a generally semicircular cross-sectional shape corresponding to the circular cross-sectional shape of longitudinal strand or wire 24 (FIGS. 5 and 8). Extending integrally from one edge of base 42 in a cantilevered fashion is a medial portion 44 ending in a section 46 which overlaps tie rod 30 and biases tie rod 30 downwardly against the tops of circumferential strands 26. Overlapping section 46 has a cross-sectional shape of an incomplete circle corresponding to the generally circular cross-sectional shape of the tie rod 30. In the preferred embodiment, the lateral ends 46 and 46" of the overlapping section 46 (FIG. 7) are wrapped around at least one half the circumference of the tie rod. As shown in FIGS. 7 and 10, however, the center section 48 of overlapping section 46 is wrapped around approximately only one quarter of the circumference of the tie rod and extends outwardly into a yieldable restraining member 50 extending along one of the stirrup projections 32.

Restraining member 50 includes a connecting portion 52 and an end portion 54 which is welded or otherwise fixedly secured to stirrup rod 32 at a location which is spaced along stirrup rod 32 beyond the hinge axis of the tie rod 30. Yieldable restraining member 50 resists any rotation of stirrup member 28, thereby tending to hold stirrup member 28 in its non-erect position. Embodiment 40 of the hinge member also includes a closed expansion loop 56 formed integrally within connecting member 52 such that connecting member 52 and end 54 are joined integrally to the opposing

elongated sides

58 and 59 of the loop. Loop 56 provides an integral expansion means which allows the yieldable restraining member 50 to stretch and elongate without breaking as the stirrup member 28 is rotated from its non-erect position to its erect position as will be described below.

Thus, it will be understood that the hinge 40 is fixedly secured via welding or the like at two positions only, i.e., at base 42 and at end 54 of restraining member 50. The intermediate overlapping section 46 biases tie rod 30 against circumferential strands 26 such that the stirrup member 28 is rotatable thereunder. Base 42 and end 54 include

indents

43 and 55, respectively, which concentrate electrical current facilitating the electric weldof these members at the appropriate places. Also, corrugations 45 are provided in the medial portion 44 and extend into overlapping section 46 to rigidify these areas and to strengthen the biasing action of these areas against tie rod 30.

Rotation of the stirrup members into the erect position as shown in FIGS. 4, 6, 7 and 9 causes an attendant expansion in the length of the yieldable restraining member 50 since its length must increase to accommodate the extra portion of the circumference of the tie rod around which it is wrapped. As will be seen from a comparison of FIGS. 8 and 9, the restraining member 50 must increase in length a distance approximately equivalent to one quarter of the circumference of the tie rod 30. As mentioned above, such expansion is accommodated via the closed expansion loop 56 in the first embodiment 40 of the hinge member. As is best seen from a comparison of FIGS. 5 and 7, the slit or gap 57 between the opposing

sides

58 and 59 of the closed loop 56 widens significantly as the ends of the loop flex or bend to accommodate the greater length. When the stirrup members 28 have been rotated into their erect position (FIG. 7) the yieldable restraining member 50 remains intact and resists any further rotation of the stirrup member after it is erected. Accordingly, the yieldable restraining member 50 retains the individual stirrup projections 32 in the erect position.

In addition to the restraining action of the yieldable restraining member 50 acting to hold the stirrup projections 32 in the erect position, the remainder of the hinge member 40 acts as a capturing means to trap the projecting end of stirrup rod 32 and prevent further rotation thereof from the erect position. As seen in FIGS. 5, 6, and 8-10, the capturing means comprise a central arm or member 60 extending in a cantilever fashion from base 42 of hinge member 40. Arm 60 is stamped from medial portion 44 of hinge 40 and has lateral slots 62 on either side thereof which extend into aperture 64 provided in overlapping section 46. Aperture 64 provides an area in the hinge into which the projecting end 34 of stirrup rod 32 is rotated when the stirrup rod is erected.

As shown in the FIGS. 5 through 10, aperture 64 includes an abutting shoulder 66 along its upper bounding edge, the shoulder being raised slightly away from the surface of tie rod 30. Shoulder 66 is also recessed slightly, as seen in FIG. 5, to accommodate the contour of the projecting end 34 of the stirrup rod 32.

As best shown in FIGS. 8 and 10, cantilever member 60 extends adjacent to, but does not engage, the end 34 of stirrup rod 32 when the stirrup is in the nonerected position. However, when the stirrup members are rotated to the erected position, the end of cantilever member 60 engages end 34 by sliding over the corner 35 of a recess or notch 36 formed on the bottom side of end 34. The end of the cantilever member 60 comes to rest within notch 36 along inclined surface 37 which is formed at an angle generally perpendicular to the angle at which the member 60 extends from the base 42 when engaging the end 34 (FIG. 9). In the preferred embodiment, this angle is approximately 5. The top side of end 34 projection 32 is squared off to form a notch or recess 38 which engages the abutting shoulder 66. Accordingly, it will be understood that when the stirrup rods are rotated to the erect position, cantilever member 60 engages notch 36 to prevent rotation of the stirrup rod in the direction toward the original nonerect position (arrow A of FIG. 9). Further, abutting shoulder 66 engages notch 38 to prevent rotation in the other direction (arrow B of FIG. 9) past the erect position which is approximately normal to the remainder of the reinforcing fabric. Thus, the projecting end 34 is trapped or captured between arm 60 and abutting shoulder 66, which elements cooperate to retain the projection 32 into the erect position and maintain it therein. Since it is desirable to produce but one size of hinge 40 and to have the one size fit many different types of stirrup members, the distances C and D, between the hinge axis and corner 35 and shoulder 66 and the inside surface of notch 36 respectively, are critical and are maintained constant on all stirrup members. Thus, these distances remain the same for any type of stirrup member as disclosed in any of the copending applications mentioned above or in this application. The distances correspond to the dimensions of hinge 40 to maintain the stirrup projection 32 in its erect position.

An alternate method of manufacture of the stirrup and hinge member to accommodate different sized stirrup members is to vary the size of the aperture 64 for different sized stirrup rods 32. In such an arrangement, the size of

notches

36 and 38 on the stirrup member 32 remain generally constant. The size of the aperture 64 is altered by clamping a removable punch and die member in the clamping die which clamps and forms the hinge member 40 to correspond to the size of the stirrup member 32.

Referring now to FIG. 11, a second embodiment 70 of the hinge member is shown, the hinge member being substantially similar in all respects to embodiment 40 of the hinge except for the inclusion of another form of the yieldable restraining member. Thus, hinge 70 also includes a base 42, an overlapping section 46 which hingedly secures the stirrup members to the fabric, a cantilever member 60 and abutting shoulder 66 which cooperate to capture the projecting end 34 of one of the stirrup rod or projections 32, and a central portion 48 of section 46 from which the yieldable restraining member 75 extends. Yieldable restraining member 75 differs from the first form 50 of the yieldable restraining member in that it includes no integral closed expansion loop. Rather, it includes a continuous connecting member 76 which integrally joins end portion 78, which is welded or otherwise fixedly secured to stirrup rod 32, to portion 48 of section 46. End 78 is secured at a location along rod 32 which is spaced beyond the hinge axis as shown in FIG. 11. Member 76 also has a scored groove 79 (FIG. 11) to facilitate elongation and/or rupturing of the yieldable restraining member. Thus, score 79 serves as a weakening means to insure that yieldable restraining means 79 will break or rupture before portion 48 is bent out of shape. Accordingly, it will be understood that yieldable restraining member 75 holds rod 32 in its non-erect position and tends to resist any rotation from that position. However, when a sufficient force is applied to the end of stirrup rod 32, the entire stirrup member 28 is rotated to the erect position causing connecting member 76 to elongate and accommodate the greater length around the circumference of the tie rod 30. Since connecting member 76 includes no expansion loop, the material from which the restraining member 75 is formed stretches at the second groove 79 as the stirrup rod is rotated. Connecting member 76 may fracture across its width at groove 79 as stirrup rod 32 is rotated fully to its erect position. After such fracture occurs, the yieldable restraining member 75 will not hold the stirrup rod 32 in the erect position. Rather, the capturing means comprising arm 60 and abutting shoulder 66 retain the stirrup rod in the erect position without any help from member 75.

Referring now to FIG. 12, yet another embodiment 80 of the hinge member is shown including another form 100 of the yieldable restraining member. Hinge member 80 is of the same type disclosed in copending application NYWM P-313, Ser. No. 381,478, referred to above and incorporated by reference herein. Hinge member 80 is generally secured via a base means 82 to longitudinally extending strand 24 and hingedly secured to a stirrup member 28 across a plurality of circumferentially extending strands 26 via an extending cantilever arm 84 including an end 86 which is contoured to correspond to the cross-sectional shape of tie rod 30. Hinge 80 includes two

lateral cantilever arms

88 and 90 which cooperate to bias the stirrup member 28 into the non-erect position and to capture and retain the member in the erect position via engagement with at least two of the rods or projections 32. Thus, cantilever arm 88 engages the top 92 of the projecting end of one of the stirrup rods 32 when the stirrup member 28 is in the non-erect position (not shown). When the stirrup member is in the erect position arm 88 engages a notch or recess 94 holding the stirrup member against rotation in the direction shown by arrow F thereby in FIG. 12. On the other hand, cantilever arm 90 engages a notch 98 of another of the extending stirrup projections 32 when the stirrup member is in the erect position thereby holding, the stirrup projection against rotation in the direction of arrow E. Accordingly, hinge 80 captures stirrup member 28 in the erect position via two of the projections 32 and prevents the rotation thereof from that position.

Hinge 80 also includes another form 100 of the yieldable restraining member comprising a spring-like cantilever arm 102 having an end 104 which is welded or otherwise fixedly secured to tie rod 30. Arm 102 includes a plurality of notches or slots 106 which extend into the arm from opposite edges of the arm. The notches of slots 106 extend from opposite edges of the arm 102 in an alternating fashion each being spaced further along the length of the arm than the next preceding slot. When the stirrup member 28 is in the nonerect position (not shown in FIG. 12) the arm 102 is substantially rectilinear and resists any rotation of the stirrup member. However, when sufficient force is applied to the member to rotate it to the erect position, arm 102 bows upwardly while the slots 106 allow the length of the arm 102 to expand or increase to accommodate the greater length between base 82 and the point at which end 104 is secured to tie rod 30 when the stirrup member is in the erect position. After such expansion, yieldable restraining member 100 remains intact and bowed slightly upwardly as shown in FIG. 12 in the erect position, thereby aiding to retain the stirrup member in that position.

Referring now to FIGS. 1 and 2, typical reinforced concrete pipes and 12 are shown in cross section including the two types of reinforcing fabrics mentioned above. Pipe 10 (FIG. 1) includes a reinforcing fabric 14 which has been roll formed into a generally elliptical cross section prior to being molded within the pipe. Fabric 14 includes stirrup projections or members 16 which are hingedly secured directly to the fabric via the hinge members of the present invention and/or those described in the copending applications referred to above. Similarly, pipe 12 (FIG. 2) includes a reinforcing fabric 18 which again has been roll formed into a generally elliptical cross section. However, instead of the stirrup members or projections being hinged directly to the fabric 18, separate fabric mats 20 including hinged stirrup projections 22 hinged thereto via the hinge means of the present invention and/or those of the copending applications referred to above are separately secured via welding or the like to the crown and invert areas of the fabric.

As will now be understood, the various embodiments of the hinge members including the yieldable restraining members act to retain the stirrup members in the non-erect position, and in most instances, also in the erect positions. The yieldable restraining members cooperate with the capturing means of the various forms of the hinge member once the stirrup members have been rotated to the erect position to retain them therein. Of course, the various forms of the yieldable restraining members may be incorporated through modifications obvious to those skilled in the art on any of the hinge members disclosed in this application or the copending application referred to above.

The terms top, bottom, etc. as used in the application are for descriptive purposes only and are not intended to limit the scope of the invention defined thereby.

While several forms of the invention have been shown and described, other forms will now be apparent to those skilled in the art. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention which is defined by the claims which follow.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fabric for reinforcing concrete pipe and the like including a plurality of longitudinal and circumferential cage defining strands; a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for joining said stirrup members to said fabric such that said stirrup members are rotatable between a non-erect position and an erect position; said hinge means including yieldable restraining means secured to each said stirrup member for holding said stirrup member in said non-erect position, said yieldable restraining means being yieldable on application of a force to said stirrup member whereby said stirrup member can be erected.

2. The fabric of claim 1 wherein said hinge means comprise individual hinge members secured to said longitudinally extending strands and hingedly securing said stirrup members substantially parallel to said longitudinal strands; the yieldable restraining means of each of said hinge members being secured to one of said stirrup projections.

3. The fabric of claim 1 wherein each of said stirrup members is rotatable about a hinge axis; said yieldable restraining means having an end extending beyond said hinge axis along one of said stirrup projections; said restraining means being secured to said stirrup projection adjacent said end of said restraining means.

4. The fabric of claim 1 wherein said hinge means includes additional means for capturing a portion of said stirrup member when it has been rotated to said erect position and for retaining said member in said erect position.

5. The fabric of claim 4 wherein said yieldable restraining means includes integral expansion means for allowing the expansion of said restraining means as said stirrup member is rotated from said non-erect position to said erect position.

6. The fabric of claim 5 wherein said expansion means comprises a narrow, elongated, closed loop formed integrally in said yieldable restraining means such that portions of said restraining means extend from opposite sides of said loop, said loop being widened as said stirrup member is rotated.

7. The fabric of claim 5 wherein said expansion means comprises an arm extending from said hinge means to said stirrup member; said arm including a plurality of slots alternately extending into either side of said arm; each slot being spaced farther along said arm than the next preceding slot on the opposite side thereof; said slots being widened as said stirrup member is rotated.

8. The fabric of claim 5 wherein said expansion means comprises an arm made of material sufficiently ductile that it stretches and elongates sufficiently as said stirrup member is rotated from said non-erect to said erect positions without fracturing before said member is completely rotated to said erect position.

9. The fabric of claim 5 comprising: weakening means in said yieldable restraining means whereby said yieldable restraining means will tend to rupture when said stirrup member is rotated to its erected position.

10. The fabric of claim 4 wherein each of said stirrup members is rotatable about a hinge axis; said yieldable restraining means having an end extending beyond said hinge axis along one of said stirrup projections; said restraining means being secured to said stirrup projection adjacent said end of said restraining means.

11. The fabric of claim 4 wherein said securing means comprise a base secured to one of said strands, said hinge means also including a section overlapping a portion of said stirrup member and contoured to the cross-sectional shape thereof, and means biasing said contoured section against said stirrup member for retaining said member against said strands; said contoured overlapping section allowing rotation of said stirrup member in two directions about a hinge axis; said capturing means conprising a cantilever arm extending from said base to a point adjacent the end of one of said stirrup projections, and a shoulder in said contoured section; said end of said one projection including a recess engaged by said cantilever arm when said stirrup member is in said erect position to prevent rotation in one of said directions; said shoulder being engaged by said end of said one projection when said stirrup member is in said erect position to prevent rotation in the other of said directions.

12. The fabric of claim 11 wherein the distance between said hinge axis and said recess is constant for all stirrup members hingedly secured to said fabric.

13. The fabric of claim 11 wherein said stirrup members each include a tie rod extending substantially parallel to said longitudinal strands; said stirrup projections comprising rods secured generally perpendicularly to said tie rod; said tie rod having a generally circular cross section, the central axis of which comprises the hinge axis of said stirrup member; said contoured section being wrapped at least around one-half of the circumference of said tie rod.

14. The fabric of claim 1 wherein said yieldable restraining means includes integral expansion means for allowing the expansion of said restraining means as said stirrup members are rotated from said non-erect to said erect positions.

15. The fabric of claim 14 wherein said expansion means comprises a narrow, elongated closed loop formed integrally in said yieldable restraining means such that portions of said restraining means extend from opposite sides of said loop, said loop being widened as said stirrup member is rotated.

16. The fabric of claim 14 wherein said expansion means comprises an arm extending from said hinge means to said stirrup member; said arm including a plurality of slots alternately extending into either side of said arm; each slot being spaced farther along said arm than the next preceding slot on the opposite side thereof; said slots being widened as said stirrup member is rotated.

17. The fabric of claim 14 wherein said expansion means comprises an arm made of material sufficiently ductile that it stretches and elongates sufficiently as said stirrup member is rotated from said non-erect to said erect positions without fracturing before said member is completely rotated to said erect position.

18. The fabric of claim 14 comprising: weakening means in said yieldable restraining means whereby said yieldable restraining means will tend to rupture when said stirrup member is rotated to its erected position.

19. A fabric for the reinforcing of concrete pipe or the like including a plurality of longitudinal and circumferential cage defining strands; a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for joining said stirrup members to said fabric; said hinge including means for securing said hinge means to said fabric, means for biasing said stirrup members into a non-erected position substantially parallel to said fabric, and additional yieldable restraining meansother than said baising means fastened to said stirrup members for resisting rotation of said stirrup members between said erect and non-erect positions.

20. The fabric of claim 19 wherein said yieldable restraining means includes integral expansion means for allowing the expansion of said restraining means as said stirrup members are rotated from said non-erect to said erect positions.

21. The fabric of claim 20 wherein said expansion means comprises an arm extending from said securing means to said stirrup member; said arm including a plurality of slots alternately extending into either side of said arm; each slot being spaced farther along said arm than the next preceding slot on the opposite side thereof; said slots being widened as said stirrup member is rotated.

22. The fabric of claim 19 wherein said hinge includes two extending arms engaging at least two of said stirrup projections; one of said arms biasing one of said stirrup projections toward said non-erected position, the other of said arms providing a stop to limit further rotation of said stirrup member when said stirrup member is erected.

23. The fabric of claim 19 wherein said hinge means comprises a plurality of hinge members; each of said hinge members including a contoured section comprising said securing means and rigidly secured to one of said longitudinal strands adjacent one of said stirrup members, a central arm extending from said contoured section hingedly securing one of said stirrup members substantially parallel to said longitudinal strand, and at least two lateral arms extending from said contoured section, one on either side of said central arm; one of said lateral arms biasing said stirrup member toward said non-erected position, and the other of said lateral arms providing a stop to limit rotation of said stirrup member when said stirrup member is rotated to its erected position.

24. The fabric of claim 23 wherein said stirrup member includes a plurality of stirrup rods joined to a tie rod; at least two of said stirrup rods being engaged by said lateral arms; said stirrup rods including recess means engaged by said lateral arms when said stirrup tending from said securing means and abutment means on said biasing means; said extending means and abutf ment means cooperating to prevent rotation of said member is in its erected position whereby said stirrup member is retained in said erected position.

25. A fabric for reinforcing concrete pipe and the like including a plurality of longitudinal and circumferential cage defining strands; a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for joining said stirrup members to said fabric; said hinge means including means for securing said hinge means to said fabric and means for capturing a portion of one of said stirrup projections in an erect position substantially normal to said fabric to retain stirrup projection when it is in said erect position.

27. The fabric of claim 26 wherein said extending means comprise an arm integral with said securing means and having an end thereon; said abutment means comprising a shoulder opposing said end of said arm.

28. The fabric of claim 25 wherein said securing means comprise a base secured to one of said strands, a section overlapping a portion of said stirrup member and contoured to the cross-sectional shape thereof, and means biasing said contoured section against said stirrup member for retaining said member against said strands; said contoured section allowing rotation of said stirrup member intwo directions about a hinge axis; said capturing means comprising an arm extending from saidsecuring means to a point adjacent the end of one of said stirrup projections, and a shoulder in said contoured'section; said end of said one projection including a recess engaged by said arm when said stirrup member is in said erect position to prevent rotation in one of said directions; said shoulder being engaged by said end of said one projection when said stirrup member is in said erect position to prevent rotation in the other of said directions.

Claims

19. A fabric for the reinforcing of concrete pipe or the like including a plurality of longitudinal and circumferential cage defining strands; a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for joining said stirrup members to said fabric; said hinge including means for securing said hinge means to said fabric, means for biasing said stirrup members into a non-erected position substantially parallel to said fabric, and additional yieldable restraining means other than said baising means fastened to said stirrup members for resisting rotation of said stirrup members between said erect and non-erect positions.

24. The fabric of claim 23 wherein said stirrup member includes a plurality of stirrup rods joined to a tie rod; at least two of said stirrup rods being engaged by said lateral arms; said stirrup rods including recess means engaged by said lateral arms when said stirrup member is in its erected position whereby said stirrup member is retained in said erected position.

25. A fabric for reinforcing concrete pipe and the like including a plurality of longitudinal and circumferential cage defining strands; a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for joining said stirrup members to said fabric; said hinge means including means for securing said hinge means to said fabric and means for capturing a portion of one of said stirrup projections in an erect position substantially normal to said fabric to retain said member in said erect position.

26. The fabric of claim 25 wherein said hinge means includes means biasing said stirrup members against said fabric; said capturing means comprising means extending from said securing means and abutment means on said biasing means; said extending means and abutment means cooperating to prevent rotation of said stirrup projection when it is in said erect position.

28. The fabric of claim 25 wherein said securing means comprise a base secured to one of said strands, a section overlapping a portion of said stirrup member and contoured to the cross-sectional shape thereof, and means biasing said contoured section against said stirrup member for retaining said member against said strands; said contoured section allowing rotation of said stirrup member in two directions about a hinge axis; said capturing means comprising an arm extending from said securing means to a point adjacent the end of one of said stirrup projections, and a shoulder in said contoured section; said end of said one projection including a recess engaged by said arm when said stirrup member is in said erect position to prevent rotation in one of said directions; said shoulder being engaged by said end of said one projection when said stirrup member is in said erect position to prevent rotation in the other of said directions.