US3471986A

US3471986A - Spacer for reinforcing mesh for concrete pipe and the like

Info

Publication number: US3471986A
Application number: US590419A
Authority: US
Inventors: Richard A Swenson
Original assignee: RICHARD A SWENSON
Current assignee: RICHARD A SWENSON
Priority date: 1966-10-28
Filing date: 1966-10-28
Publication date: 1969-10-14
Anticipated expiration: 1986-10-14

Description

Oct. 14, 1969 R. A. SWENSON 3,471,986

SPACER FOR REINFORCING MESH FOR CONCRETE PIPE AND THE LIKE FiledOct. 2a. 1966 FIGB. i FIG-4.

IG S

I INVENTOR RICHARD A.SWENSON HIS ATTORN EYS United States Patent US. Cl. 52-652 6 Claims ABSTRACT OF THE DISCLOSURE A snap-on spacer element for structural reinforcing mesh formed from a flat band of spring type metal to have a hook at one end to receive a rod of the reinforcing mesh. The other end of the member is formed in an S-shaped hook which can be snapped over a parallel rod of the mesh to firmly retain the spacer element in position by the resilient force of the element. The central portion of the spacer includes a shank portion extending substantially parallel to the reinforcing mesh and a V- shaped projection portion extending from the shank portion to space the mesh from a surface.

This invention relates to the manufacture of concrete pipe, and more particularly to devices for accurately loeating and positioning reinforcing material such as reinforcing mesh or fabric in molds for concrete pipe.

In the manufacture of concrete pipe, wet concrete is poured into a mold having an annular cavity which imparts the proper shape and form to the finished product. It is quite common to position in the mold before the concrete is poured into it, a sleeve or cage of steel reinforcing mesh which becomes embedded in the concrete and greatly strengthens the resulting pipe. It is well recognized in the art that the positioning of the reinforcing mesh with respect to the inner and outer surfaces of the walls of the pipe is very important in producing strong pipe, that is, if the mesh is too close to or too far from either the inner or outer surface, the pipe is weakened and will be weakened further as the reinforcing decomposes due to inadequate concrete cover protection. Moreover, if the mesh is not located generally co-axially with respect to the center line of the pipe, the wall strength of the pipe will vary and thus the pipe will not give satisfactory service or meet standards for such pipe.

For the above reasons, various expedients have been proposed for positioning the mesh in the mold or form so that when the concrete is poured into the mold, the mesh will be retained in a predetermined position with respect to the inner and outer surfaces of the pipe. Among the expedients proposed are spacers welded to the mesh which project outwardly beyond the plane of the mesh to contact the mold and thus space the mesh more or less uniformly with respect to the outer or inner walls of the mold. This expedient is expensive because of the welding operations involved and, moreover, is not very satisfactory because of the tendency of the welding heat to warp and deform the spacers as well as the mesh itself and to burn away some of the required mesh reinforcement.

Another practice is to cut the mesh and bend portions out of the plane of the mesh to form spacing legs which contact the mold at various points along the length and width of the mesh. This practice likewise is not very satisfactory because unless the mesh is cut and bent quite accurately, the lengths of the legs vary and produce an inaccurate location of the mesh in the mold. Moreover, by cutting the mesh, its overall strength is reduced with the result that pipe containing such mesh is either weaker or additional reinforcement is required to re-establish the strength of the mesh.

Another type of spacer is a bent hairpin-like hook which is hung over a portion of the mesh and bears against other ortions of the mesh to space the mesh from the wall of the mold. These spacer hooks, in practice, are not very satisfactory because when the concrete is poured into the mold, which is usually in a vertical position, spacers sometimes are dislodged and fall to the bottom of the mold so that the reinforcing mesh can shift and move relative to the walls of the pipe mold even to the extent that portions of the mesh are exposed at the inner or outer surfaces of the pipe.

In accordance with the present invention, spacers are provided which are inexpensive to produce and can be attached securely and quickly to the reinforcing mesh so that they cannot be dislodged during pouring of the concrete into the mold thereby assuring accurate spacing of the mesh with respect to the inner and outer walls of'the mold and proper positioning of the mesh in the concrete pipe to obtain maximum strength.

More particularly, in accordance with the present invention, the spacers may be formed of a spring type metal having a hook at one end which can be hooked over one of the bars, wires or rods of the reinforcing mesh and a curved and hook-like opposite end which can be snapped over another wire or rod of the mesh to securely retain the spacer in position. A corrugation or projection is provided on the spacer which serves to space the generally sleevelike reinforcing mesh from the wall of the mold by either engaging the inside or the outside of the mold thereby locating the mesh accurately with respect to both walls of the pipe mold. By providing a series of such spacers along the length and Width of the mesh, little or no displacement of the mesh can occur during the molding of the pipe, and also due to the strong retention of the spacers on the mesh, they are not dislodged by pouring the concrete and by tamping, vibrating or other operations involved in the manufacture of the pipe so that the reinforcing mesh cannot shift to an eccentric or canted position with respect to the inner and outer surfaces of the finished pipe and the walls of the mold.

For a better understanding of the present invention, reference may be had to the accompanying drawings, in which:

FIGURE 1 is a plan view of an annular mold for concrete pipe illustrating the positioning of a concrete reinforcing mesh or fabric in the mold by means of spacers of the type embodying the present invention;

FIGURE 2 is a view in section taken on line 2-2 of FIGURE 1;

FIGURE 3 is a side elevational view of a spacer embodying the invention applied to a portion of concrete reinforcing mesh, shown in section;

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 3; and

FIGURE 5 is a side elevational view of a modification of the spacer applied to a section of reinforcing mesh.

Referring to FIGURE 1, a typical pipe mold includes an inner, usually hollow cylindrical core 10 formed of any suitable material such as, for example, steel, and an outer cylindrical mold member 11 formed of similar material. The core and outer mold member can be split into one or more parts to enable the removal of the pipe from the mold.

As indicated in FIGURE 1, it is common to reinforce concrete pipe with one or more layers or cages or sleeves 12 of concrete reinforcing mesh comprising longitudinal wires, bars or rods 13 welded to transverse wires, bars or rods 14 to form a metallic mesh fabric, the spacing of the wires varying as the purpose demands. Thus, reinforcing mesh having 2-, 3-, 4-inch or greater spacing of the wires or rods, and even unequal spacing of the vertical and transverse wires may be provided.

As indicated above, in order to provide concrete pipe of optimum strength characteristics, it is essential to have the reinforcing mesh spaced uniformly with respect to the outer or inner surfaces of the walls of the finished pipe, the actual spacing depending upon the section of the pipe, e.g., the thickness of the concrete wall of the pipe. To this end, and in accordance with the invention, spacers of the type shown in FIGURES 3 to are provided. The spacers are formed preferably of spring metal strip such as, for example, medium to high carbon tempered steel strip. In practice, the strip may be about of an inch wide by about .050 of an inch thick. These dimensions can be varied so long as the spacer is of sulficient strength and resiliency for the purpose. One end 15 of the spacer 16 (FIGURES 3 and 4) is bent into hook-like shape so that it can be hooked over one of the horizontally disposed rods or Wires 14 of the mesh, for example. The opposite end 17 of the strip is bent into a generally S-shaped formation so that it can be forced over a parallel rod or wire 14 of the reinforcing mesh and snapped into position and locked to the mesh by the springiness of the snap spacer. Between the

ends

15 and 17, the strip is bent to form a generally V-shaped projection 18 of a height which determinees the spacing of the mesh 12 from the outer or inner wall 11 or of the pipe mold. Thus, for example, in a typical snap spacer, the height of the V-shaped projection may be on the order of 1 inch or less to 2 inches or more, depending upon the wall thickness of the finished pipe and the desired location of the mesh in the pipe wall. The shape of the hook 17 and the width of the strip will prevent the spacer from being deflected or canted sideways by stresses thereon, thereby further assuring proper centering or positioning the mesh relative to the surfaces of the concrete structure. The overall length of the spacer may be varied as the purpose demands and it may be of such length that it merely spans the spacing between two wires or rods of a 2-inch mesh, a 3-inch mesh or a 4-inch mesh or, as illustrated in FIGURES 3 and 4, the length may be such as to span two meshes so that it can be used on, for example, a 4-inch mesh or a 2-inch mesh. With a four inch spacer used with a 2-inch reinforcing mesh, as illustrated in FIGURES 3 and 4 the projection 18 is offset nearer one of the ends of the spacer so that the intermediate rod or wire 14' bears against the back of a straight shank portion of the spacer, which thus gives it still additional supporting strength when under stress as the mesh is positioned in the mold. The spacer 26 shown in FIGURE 5 is similar to the spacer 16 but is of such length that it spans only one pair of bars or rods of the mesh 27. In this type of snap spacer, the projection can be spaced equidistant from the ends of the spacers.

The shape of the projection 18 is susceptible to modification, for example, instead of being V-shaped the spacing projection 18 may be U-shaped, arcuate, or of other suitable form, so long as it projects sufficiently from the mesh toward the wall of the pipe mold to assure substantial concentricity of the sleeve or reinforcing mesh in the finished pipe. However, a V-shaped projection is preferred for the reason that less material is required in the spacer and it resists better any stresses tending to distort it or disengage it from the mesh.

Other variations and modifications of the spacer and the uses thereof are possible within the scope of the invention and accordingly, the forms of spacers illustrated in the drawings should not be considered as limiting the invention defined in the following claims.

I claim:

1. A concrete reinforcing structure comprising a mesh of the type having a series of uniformly spaced substantially parallel wires, and a releasable spacer for locating a point on the mesh in spaced apart relation to a surface including a resilient member having a first hook formed at one end thereof receiving a wire of the mesh and a second S-shaped hook at the other end thereof yieldably engaging a parallel wire of the mesh to releasably and firmly secure the member to the mesh by the resilient reaction force between said S-shaped hook and the parallel wire, and a projection on said member for maintaining said mesh in spaced relation to the surface.

2. The structure of claim 1 in which the distance between the first and second hooks is equal to a multiple of the distance between adjacent parallel wires of the mesh.

3. A concrete reinforcing structure comprising a mesh of the type having a series of spaced substantially parallel wires, and a releasable spacer for locating a point on the mesh in spaced apart relation to a surface including a resilient member having a first hook formed at one end thereof receiving a wire of the mesh, a second hook at the other end thereof yieldably engaging a parallel wire of the mesh to releasably secure the member to the mesh, a projection on said member for maintaining said mesh in spaced relation to the surface, and a straight shank portion intermediate the projection and one of the ends and engaging at least a point of the surface of a parallel wire between the wires engaged by the first and second hooks.

4. A snap-on spacer for locating in spaced apart relation to a surface structural mesh including spaced wires, comprising a unitary member of relatively stiff, wide spring material having at one end thereof firsthook means for receiving a wire of the reinforcing mesh and having at the other end thereof an S-shaped hook including a concave surface for engaging the surface of the wire and a convex lip for guiding the hook over the surface of the wire, thereby to releasably secure the spacer to the wires of the mesh, and a projection on said member extending normal to the mesh when the first and second hook means engage the parallel wires and having a projection distance from the mesh equal to the desired spacing between the mesh and the surface.

5. A spacer as defined in claim 4, in which the concave surface of the S-shaped hook means is concave toward the other hook means to maintain the member in longitudinal tension.

6. A snap-on spacer for locating structural reinforcing mesh in spaced apart relation to a surface, comprising a unitary member of flat relatively stiff but resilient material having at one end thereof first hook means for receiving a wire of the mesh and having at the other end thereof second S-shaped hook means to yieldably pass over a parallel wire of the mesh during attachment of the member to the mesh and thereafter firmly engage the parallel wire, said hook means being joined by a relatively straight shank portion and a bent projecting portion extending outwardly from the mesh when the member is attached thereto.

References Cited UNITED STATES PATENTS 1,379,625 5/ 1921 Hartman. 1,421,807 7/1922 Metzger 52-684 3,257,767 6/1966 Lassy 52-652 J. SPENCER OVERHOLSER, Primary Examiner JOHN S. BROWN, Assistant Examiner US. 01. x12. 25-118; 52-449, 414; 249-91