US3430407A - Spacer members for use in reinforced structures - Google Patents

Description

F. W. BERRY March 4, 1969 SPACER MEMBERS FOR USE IN REINFORCED STRUCTURES Sheet Filed April 10, 1967 I nventor m Y m a m m z w wy B MML W F. w. BERRY 3,430,407

SPACER MEMBERS FOR USE IN REINFORCED STRUCTURES March 4, 1969 Sheet Filed April 10, 1967 Fi g .4-

Inventor F- w. B RR flttorneys United States Patent 16,720/ 66 US. Cl. 52-689 2 Claims Int. Cl. E04e 5/16 ABSTRACT OF THE DISCLOSURE This invention relates to spacer members for use in reinforced concrete structures, and in particular to members which are employed to support and locate reinforcements, such as reinforcing rods, in a mould whilst concrete is poured into the mould, the spacer members, together with the reinforcing rods, being permanently cast into the resultant cast structure. The spacer member is moulded from a synthetic plastics material so as to comprise an apertured, concave, reinforcement-receiving saddle portion carried by an integral framework base portion having a lower interrupted edge on which the spacer member rests when supporting and spacing a reinforcement from the base of the mould.

The present invention relates to spacer members for use in reinforced concrete structures. Such members are generally employed to maintain reinforcing elements, such as rods or bars, mutually spaced, and spaced away from the shuttering or mould in which the structure is to be cast, whilst concrete is poured into the shuttering or mould, and sets, and are permanently cast into the structure with the reinforcements.

More particularly, the invention relates to spacer members moulded or otherwise formed from a synthetic plastics material. The use of such materials for spacer members presents certain problems due to the fact that the materials employed are generally not compatible with, and do not bond to, the concrete of the structure into which they are cast, so that spaces are formed between the spacer members and the concrete of the structure which provide comparatively unrestricted passages enabling moisture to reach and corrode or otherwise attack the reinforcements in the cast structure. For this reason the use of such spacer elements has hitherto been confined to locations well within the bodies of the concrete structures, since, should the spacer members penetrate the surfaces of the structures and thus be exposed directly to the environment surrounding the structure, any moisture in this environment is likely to readily pass directly along the surfaces of the spacer members, possibly with the assistance of capillary action, to the reinforcements. Moreover, should the spacer members be located only just beneath the surfaces of the structures, due to the lack of bonding between the concrete and the spacer members, spalling is likely to occur, i.e. the thin layer of concrete between each spacer member and the surface of a cast structure, is likely to break away and expose the spacer member.

It is an object of the present invention to provide a synthetic plastics spacer member which may be used as bearer to support and space reinforcements from the base or floor of a mould or shuttering, and which, although it may rest on the base prior to casting, is of such a construction that the risk of spalling, or penetration of the surface of the cast concrete structure by the spacer element, is reduced or eliminated.

Accordingly, the present invention consists in a synthetic plastics spacer member comprising a reinforcement-receiving saddle portion carried by an integral framework base portion having an edge on which the spacer member is intended to rest when supporting a reinforcement from a mould or shuttering, said edge being interrupted along its length. The saddle portion is channelled or concave so as to receive, locate and support a metal reinforcing bar or rod, and the framework base portion comprises a number of Webs depending from and integral with the underside of the saddle portion, the webs, when viewed from beneath the spacer member, having a generally H-shaped configuration. The lower edges or surfaces of the webs, which rest on the base of the mould or shuttering during casting of the structure, are castellated or otherwise recessed so as to interrupt the line or zone of contact between the said lower edges and the base of the mould or shuttering.

In order that the invention may be readily understood, one embodiment thereof will now be described with reference to the accompanying drawing, in which:

FIGURE 1 is a perspective view from above of a spacer member;

FIGURE 2 is a side elevation of the spacer member shown in FIGURE 1;

FIGURE 3 is an end elevation of the same spacer member; and

FIGURE 4 is an underneath plan view of the same spacer member.

Referring to the drawing, the spacer member is moulded in one piece from a synthetic plastics material such as high density polythene. It comprises an arcuate saddle portion 1 defining an upper surface for locating and supporting a reinforcement, which surface may c0rrespond in curvature to the diameter of the reinforcement, i.e. an iron or steel reinforcing bar, rod or other elongated element (not shown), to be supported thereon. It will be understood, however, that the spacer member may alternatively be used to support reinforcing elements of greater or smaller diameter. Depending from opposite longitudinal ends of the saddle portion 1 are a pair of integral transverse end walls or webs 2, formed with upright stiffening ribs 3, and interconnected by a longitudinally extending central web 4. Extending outwardly of the end walls 2 are triangular fillets 5.

The lower edges or surfaces of the end walls 2 and Web 4, on which the spacer member is intended to rest when in use, are castellated by the provision of recesses 6 which interrupt the line or zone of contact of the spacer member with the surface on which it is positioned, for example the base or floor of a mould or shuttering. In addition the saddle portion 1 is provided with a central aperture 7, and the web 4, where it underlies the aperture 7, is provided with recesses 8 on each side of a land 9 on the same level as upper surface of the saddle portion 1.

By virtue of the particular configuration and disposition of the walls 2 and webs 4 and 5, these latter elements may be comparatively thin, for example, a wall thickness of .080" is sufiicient to enable the spacer member to support considerable loads without collapse. Such loads may arise from the weight of the reinforcement resting on the spacer member and from the weight of construction trafiic which may pass over the reinforcement before the concrete has been poured, or has fully hardened, when structures such as floor sections or beams are being cast in situ.

In use, reinforcing rods or bars which are to be cast into a structure adjacent the floor of a mould or shuttering, are each supported along their length, and spaced from, the base or floor of the mould by a number of the illustrated spacer members. Each reinforcement rests in the saddle portions 1, and the recessed lower edges of the walls 2 and webs 4 and 5, prior to casting, rest on the base of the mould. The structure is then cast in the usual manner by pouring liquid concrete into the mould around the spacer members, reinforcements supported thereby, and any other reinforcements or elements to be cast in which may be provided, tamping the concrete and allowing it to set, whereafter the cast structure is separated from the mould.

Although, prior to casting, the recessed lower edges of the spacer members rest on the base of the mould, a layer of concrete is, in practice, formed over these edges during casting, so that the spacer members do not penetrate the surface of the final cast structure. Due to the provision of the recesses 6 in the lower edges of the walls 2 and webs 4, it has been found that the thickness of the said layer is increased in comparison with that formed when no such recesses are provided and the lower edges are continuous. Moreover, since the liquid concrete flows through the recesses 6 during casting, continuity is preserved between the concrete on opposite sides of the Walls 2 and webs 4 other than merely by the said layer. Due to the above, spalling or break-away of the said layer has been found to be reduced or eliminated by employing spacer members of the type described and illustrated.

Provision of the aperture 7 and recesses 8 in the saddle portion 1 and web 4 respectively, permits liquid concrete to fiow into engagement with the underside of the reinforcement, and also enables any air trapped in the spacer member to escape.

If desired, a spacer member may be attached to the reinforcement which it is to support, for example, when the base of the mould or shuttering is not horizontal or even, by passing a length of wire or the like transversely through the recesses 8 in the web 4 and looping and securing it around the reinforcement. Alternately, the spacer member may be provided with a spring clip, of a similar type to that disclosed in my British Patent No. 1,042,918, or No. 988,538, comprising a spring wire loop hinged at one side of the saddle portion 1 and engageable in a notch or notches, or with one or more projections at the opposite side of the saddle portion 1. The loop, when so latched, extends across and resiliently engages a reinforcement resting in the saddle portion 1 to retain the reinforcement assembled to the spacer member.

It will be understood that various modifications may be made without departing from the scope of the present invention. For example, the material, colour and dimensions of the spacer member may be varied. In particular, the cover, i.e. the distance of the lower edges of the framework base portion of the spacer member from the saddle portion, may be varied depending upon requirements and upon the dimensions of the reinforcement to be supported. When the cover or height of the spacer member is increased, the fillets 5, which serve to improve the stability of the spacer member, may correspondingly be increased in size, and in this event, the lower edges of these fillets may also be provided with recesses similar to the recesses 6.

Likewise, the curvature of the saddle portion may be varied to accommodate different diameter reinforcements, although it is generally acceptable in practice for the saddle portion to have a curvature corresponding to the diameter of the largest reinforcement to be supported, so that the saddle portion will also satisfactorily accommodate elements of smaller diameter.

I claim:

1. A synthetic plastics spacer member for use in reinforced concrete structures, comprising a saddle portion channelled to locate and support a reinforcement and carried by an integral framework base portion comprising a plurality of webs depending from and integral with the underside of the saddle portion, and having, in crosssection, an H-shaped configuration, the webs having lower interrupted edges on which the spacer member is intended to rest when supporting a reinforcement from a mould or shuttering, the saddle portion being provided with a central aperture, and one of said webs underlying the aperture and being provided, in the region of the aperture, with upwardly directed recesses disposed on each side of a land on a level with the reinforcementsupporting surface of the saddle portion.

2. A spacer member as claimed in claim 1, wherein the transverse web of the H is extended laterally of the longitudinal webs, by oppositely directed generally triangular fillets.

References Cited UNITED STATES PATENTS 3,191,345 6/1965 Schwachula 52689 3,290,842 12/1966 Aberg 52-689 3,325,959 6/1967 Torp 52-689 FOREIGN PATENTS 208,214 10/ 1966 Sweden. 1,094,958 12/ 1960 Germany. 1,413,826 8/ 1965 France.

FRANCIS K. ZUGEL, Primary Examiner.

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