US3426810A - Method of producing a grid reinforcement for concrete - Google Patents

Description

Feb. 11, 1969 v sc oc ET AL 3,426,810

METHOD OF PRODUCING A GRID REINFORCEMENT FOR CONCRETE Filed June 27, 1966 Sheet I of 2 Feb. 11, 1969 H. SCHOCH ET AL 3,426,810

METHOD OF PRODUCING A GRID REINFORCEMENT FOR CONCRETE Filed June 27, 1966 Sheet g of 2 E 2 3;: amasq g E m 5 i 9 United States Patent Office 3,426,810 Patented Feb. 11, 1969 3,426,810 METHOD OF PRODUCING A GRID REM- FORCEMENT FOR CONCRETE Hans Schoch, Lugano, and Carlo Gaggini, Elgg, Zurich,

Switzerland, assignors to Ernst Schoch Aktiengesellschaft, Basel, Switzerland Filed June 27, 1966, Ser. No. 560,625

US. Cl. 140--93 Int. Cl. B21f 27/20, 15/04, 27/06 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method of producing a grid reinforcement for concrete, such reinforcement comprising at least one layer of parallel bending-resistant reinforcing rods which are interconnected by flexible spacers, the same crossing the rods, and which are retained by U- shaped loops formed in the spacers and twisted together.

It is an object of the invention to provide an improved method of forming a grid reinforcement and to this end there is provided a method of securing flexible and flexurally stiff reinforcement members in a grid reinforcement for concrete, comprising the steps of supplying a flexible reinforcement spacer to a securing location, laying a flexurally stiff reinforcement rod across said flexible spacer forming a U-shaped loop in said flexible spacer at either side of said reinforcement rod, such loops being coplanar with said spacer, and then twisting said loops together to secure said reinforcement rod and said flexible spacer together.

According to the invention apparatus for carrying out the method described above comprises a base plate providing a securing location, means for feeding a flexible spacer to the securing location, means for feeding a flexurally stifl reinforcement rod to the securing location to lie across the flexible spacer, means for forming a U- shaped loop in the flexible spacer at either side of the reinforcement rod coplanar with the flexible spacer, and gripping and twisting means movably mounted above said base plate for gripping the U-shaped loops and twisting the loops together to secure the reinforcement rod and flexible spacer together.

Further objects and advantages of the invention will become apparent from the following description with reference to the accompanying drawings.

In the drawings:

FIGURES 1 to 3 show how loops in a flexible spacer are formed, twisted and pressed against a reinforcing rod in accordance with the invention;

FIGURE 4 shows a grid reinforcement for concrete having two layers of reinforcing rods;

FIGURE 5 is a schematic view of apparatus for forming and pressing the loops; and,

FIGURE 6 is a vertical section, at 90 to the sectional part of FIGURE 5, through a part of the apparatus shown therein.

FIGURES 1 to 3 show part of a grid reinforcement comprising a reinforcing rod 1, which can be made of nonweldable steel, and a spacer 2 which can be a wire or a filament of an appropriate plastics. A first loop 3 is formed on one side of the rod 1, and a second loop 4 is formed on the other side of the rod -1 as shown in FIG- URE 1 so that a single thickness of wire 5 extends below the rod 1 while such rod is engaged on either side by loops 3 and 4. In the drawings the loops 3 and 4 are shown as being disposed in a plane perpendicular to the axis of the rod 1; however, the plane in which the loops are disposed could form an acute angle, more particularly an angle of 45 with the axis of the reinforcing rod.

The two loops 3 and 4 are engaged, by apparatus to be described hereinafter, and twisted together, by 1%, or 2% or 3% turns, and rings 6 and 7 being formed and the loops taking up the position shown in FIGURE 2. The same apparatus having been disengaged from the loops and turned through is used to press the loops against the rod 1 so that the loops lie flat thereon (see FIGURE 3).

Similarly, crossing rodsi.e., rods disposed in two layers one above anothercan, as diagrammatically shown in FIGURE 4, be connected by spacers extending diagonally at 45 to them. In this event, the loops formed from the spacers lie flat on the top reinforcing rods. If required, a similar effect can be achieved with two single grid reinforcements placed in crossing relationship one above another.

The apparatus for producing loops in a spacer, twisting such loops and finally pressing them against the reinforcing rods, can comprise, for instance, a shaft having on it staggered pairs of cams for producing the loops 3 and 4 shown in FIGURE 1. The spacing between the pairs of cams corresponds to the spacing between the rods. The shaft can be driven manually or mechanically. Using cams to produce the loops has the advantage that if the spacer consists of a thin wire or the like, reliable guidance thereof is provided and the loops produced are uniform and clean. Reliable guidance during formation of the loops 3 and 4 and of the end rings 6 and 7 is very important with circular cross-section spacers, for with such spacers it has previously been impossible to avoid disturbances during shaping when unguided portions pass by.

The drive for a twisting tool for twisting associated loops 3 and 4 together around a reinforcing rod can be derived from the shaft carrying the loop-forming cams. One such twisting tool, which also serves as a pressing ram, is provided at each twisting station. Each such tool comprises a pair of co-operating jaws which are pneumatically or hydraulically driven to grip the loops 3 and 4 and twist the same together as hereinbefore described. Once the loops have come into the position shown in FIGURE 2, the clamping jaws of the twisting tool open and the same are turned through 90 away from the loops; they then serve as pressing rams which are pressed either against the rod 1 or against the top rod in FIGURE 4, so that the loops take up the position shown in FIG- URE 3.

The apparatus for performing the method according to the invention is shown schematically in FIGURES 5 and 6 and comprises a baseplate 10 (see FIGURE 5) to which rods 1 for interconnection by spacers 2, e.g., wires, are supplied via a supply or feeder plate 11.

Two reinforcing rods 1 are shown in FIGURE 5; the right-hand rod 1 has already been linked with the spacer, which will hereinafter be referred to as wire, but which, as previously mentioned, can be made of plastics, whereas the rod on the left just has the two loops 3 and 4 extending below it. Only one wire 2 is shown in FIGURE 5, but one wire and one twisting device are of course provided for each twisting or working station disposed consecutively along the length of the rods 1.

The wire 2 is wound off a supply reel 12 and goes along the surface of the baseplate 10 through a brake 13 which comprises a bar or plate 15 loaded by a spring 14 and serves to keep the wire in tension. The same purpose could be achieved by a brake, for instance, a sprin brake, acting directly on the supply reel 12. After going through the brake the wire 2 goes below a stationary jaw 16 which is disposed on one side of an aperture 17 in the baseplate 10 and which has on its left-hand side in FIGURE "a projection 16'; the same guides the rod 1 and prevents the same from rising during formation of the loops. Disposed on the other side of the aperture 17 is a movable jaw 18 which can move from the operative position, shown in solid lines in FIGURE 5, through another aperture 19 n the baseplate into the inoperative position, shown in broken lines. The abutment or jaw 18 is rigidly mounted on a shaft 18' which can rotate around its axis and is also adapted for lengthwise movement. The actuating mechanism for the jaw 18 is not shown in any greater detail but matters are so arranged that when in its inoperative position the jaw 18 is in a different plane-perpendicular t0 the shaft 18'-as compared with when it is in its operative position.

Disposed on the top of the baseplate 10 is a stationary abutment 20 for the rod 1 which has already had the wire 2 secured to it. The distance between the abutment 20 and the stationary jaw 16 corresponds to the spacing of the reinforcing rods 1; to alter this spacing the abutment 20 can be adjustable or displaceable on the baseplate 10.

Disposed vertically above and centrally between the jaws 16 and 18 is a device which has the general reference 21 and which serves to twist the loops 3 and 4 together and to press them down on to the rod 1. To form the loops 3 and 4 two push-rods 24 and 25, adapted to be operated independently by eccentric rollers 22 and 23, are disposed below the aperture 17. Staggered eccentric discs 26 and 27 operate the rollers 22 and 23 so that the push-rod which is on the right in FIGURE 5 rises first to form the loop 4 and the push-rod 24 then rises, the push-rods taking up the position shown in FIGURE 5 and the loop 3 being formed by more wire 2 being pulled along. Thus the push-rod 25 remains in its top position until the push-rod 24 has formed the loop 3. The two push-rods stay together in the top position, in which they retain the loops and keep the shape thereof stable, until the device 21 to be described hereinafter engages the loops. The loops are therefore not deformed, a feature which is essential if the finished grid reinforcement is to be uniform. The eccentric discs 26 and 27 are disposed on a shaft 29 driven by bevel gears 28. The loops 3 and 4 shown in FIGURE 1 of the drawings are therefore produced by that part of the equipment which is below the baseplate 10. The push-rods 24 and 25 can be of upwardly convergent shape.

The device 21 which serves to twist the loops 3 and 4 together and then to press them against the reinforcing rod is rotatable as a whole around its vertical axis and is also vertically movable, that is, it can move towards and away from the rod 1. The device 21 is rotatable by a bevel gear 30 which is rigidly connected to it and which meshes with a worm 32 disposed on a drive shaft 31. Axially movable clamping jaws 34 and are mounted inside casing 33 of device 21, such jaws being interconnected by a spring clip 36. A push-rod 37 movable in casing 33 can move the jaws 34 and 35 along the conical inner wall of the bottom part of the casing 33. The inner wall of the casing which guides the jaws 34 and 35 has an inclination of from 10 to and the opening angle of the frustum bounding the bottom end of the jaws is from 75 to 90. The push-rod 37 has at its bottom end a disc 38 engaging in grooves 39 in the jaws 34 and 35 so that the same are constrained to move axially with the rod 37, the top end of which is connected to a piston 40 movable, against biasing of a spring 41 in the casing 33, by a pneumatic or hydraulic pressure medium supplied through a line 42.

The plate 11 is formed with an aperture into which an abutment 43 rotatable about a spindle 44 can extend.

When in the position shown, the abutment 43 prevents a rod 1 from being supplied to plate 10. When the abutment 43 is pivoted anticlockwise, the rod 1 is released and slides down plate 11 into position beneath device 21.

The apparatus described above operates as follows:

In the position shown in FIGURE 5 a rod 1 to which Wire 2 has been secured is in contact with the abutment 20, the wire 2 is moving over the surface of the baseplate 10 off the reel 12 below the brake 13 and stationary jaw 16 and through the apertures 17 and 19 and the moving jaw 18 is in its normal position. The moving abutment 43 is first operated to release a rod 1 and the same slides down along the plate 11 into position beneath device 21. The moving jaw 18 then moves into the operative position, shown in solid lines in FIGURE 5, the push-rod 25 rises to form the loop 4 and stays in the top position; once the loop 4 has been finished the push-rod 24 rises to form the loop 3. Consequently, the rod 1 has a piece of wire 5 extending below it and loops 3 and 4 on either side.

Pressure medium is then supplied to the chamber above the piston 40 so that it descends together with the pushrod 37 which pushes the jaws 34 and 35 to engage the top ends of the loops 3 and 4. The device 21 is then rotated so that the loops 3 and 4 are twisted together. Twisting is performed as hereinbefore described by the device performing 1% or 2% or 3% revolutions. The resulting end rings 6 and 7 are disposed in a longitudinal plane of the reinforcing rod. The pressure medium is then released so that the rod 37 opens the jaws 34 and 35, the drive 30 and 32 rotates the device 21 through and the pressure medium is again supplied to the chamber above the piston 40 causing the rod 37 of the device 21 to descend toward the rod 1.

Means (not shown) then force the device 21 down against the rod 1, the jaws 34 and 35 both acting as hammers to flatten the end rings 6 and 7 of the wire against the rod 1.

If the material used for the spacers is a plastically deformable plastics, the two loops 3 and 4 can be formed simultaneously.

We claim:

1. A method of producing a reinforcement network for concrete, comprising the steps of supporting a plurality of flexible spacer strings in parallel relation to each other; successively placing a plurality of rigid reinforcement rods in spaced parallel relationship across said spacer strings; pushing portions of said spacer strings upwardly at both sides of each of said reinforcement rods to form each spacer string into a pair of substantially U-shaped loops projecting upwardly above said reinforcement rod one at each side thereof and in close proximity thereto; clamping said pair of loops at their projecting end portions to hold them securely; and twisting said pair of loops together through .at least 1% revolutions while retaining the hold on their projecting end portions to cause said spacer string to firmly encircle the reinforcing rod while the extreme parts of said projecting end portions retain their loop shape.

2. The method as set forth in claim 1, including the step of twisting said pair of loops together through 2% revolutions.

3. The method as set forth in claim 1, including the step of twisting said pair of loops together through 3% revolutions.

4. The method as set forth in claim 1, including the step of. bending the untwisted parts of said projecting loops in\opposite directions and press them down onto the top side of said reinforcement rod.

5. An apparatus for producing a reinforcement network for concrete, comprising in combination: means for supporting a plurality of flexible spacer strings in parallel relation to each other, said supporting means having an opening therethrough below a portion of each of said spacer strings; means for positioning one of a plurality of rigid reinforcement rods across said spacer strings above said openings in the supporting means; pusher means below said supporting means in register with said openings therein; means associated with said pusher means for intermittently forcing them upwardly through said openings against said spacer strip at both sides of said reinforcement rod thereby causing the spacer strip to form a substantially U-shaped loop projecting upwardly above the reinforcement rod at each side thereof; clamping jaws above each of said openings in a position to grip the extreme end portions of said pair of loops between them; actuating means associated with said clamping jaws to cause them to close firmly on said pair of loops; and means for rotating said actuating means through at least 1% revolutions about an axis transverse to the longitudinal axis of said reinforcement rod thereby to twist said pair of loops to firmly encircle said reinforcement rod while causing the extreme end portions of said loops to retain their loop shape by being clamped between said clamping jaws.

6. The apparatus as set forth in claim 5, in which said means associated with said pusher means comprises two eccentrics each connected with one of said pusher means.

7. An apparatus for producing a reinforcement network for concrete, comprising in combination: means for supporting a plurality of flexible spacer strings in parallel relation to each other, said supporting means having an opening therethrough below a portion of each of said spacer strings; means for positioning one of a plurality of rigid reinforcement rods across said spacer strings above said openings in the supporting means; pusher means below said supporting means in register with said openings therein; means associated with said pusher means for intermittently forcing them upwardly through said openings against said spacer strip at both sides of said reinforcement rod thereby causing the spacer strip to form a substantially U-shaped loop projecting upwardly above the reinforcement rod at each side thereof; clamping jaws above each of said openings in a position to grip the extreme end portions of said pair of loops between them; actuating means associated with said clamping jaws to cause them to close firmly on said pair of loops; means for rotating said actuating means through at least 1% revolutions about an axis transverse to the longitudinal axis of said reinforcement rod thereby to twist said pair of loops to firmly encircle said reinforcement rod while causing the extreme end portions of said loops to retain their loop shape by being clamped between said clamping jaws; said actuating means comprising a housing movable toward and away from said opening in the supporting means and having a bottom opening and a downwardly tapering interior side wall extending upwardly from said bottom opening for sliding engagement with the outer sides of said clamping jaws; resilient means interconnecting said clamping jaws to yieldably urge them into engagement with said tapering interior side walls of the actuating means; a plunger slidably mounted in said housing; means connecting said plunger with said clamping jaws; spring means yieldably urging said plunger upwardly in said housing; and means for admitting pressure fluid to the top side of said plunger to overcome the action of said spring means thereby to force said clamping jaws downwardly through the bot tom opening of said housing to clamp said loops between them, the vertical movability of the housing also permitting its use as a means for pressing said loops down onto the reinforcement rod after the twisting operation.

8. The apparatus as set forth in claim 7, in which the taper angle of said interior side wall of the housing is between 10 and References Cited UNITED STATES PATENTS 540,136 5/1895 Blaisdell 149 1,821,506 9/1931 Foulder 14093 3,211,187 10/1965 Paule et a1. 140-93.6 3,263,597 8/1966 Stychinsky et a1. 140119 3,354,915 11/1967 Johnson et a1. 14093 3,356,110 12/1967 Tuit 14071 RICHARD J. HERBST, Primary Examiner. E. M. COMBS, Assistant Examiner.

U.S. Cl. X.R.

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