Abstract:
A shoe for use with a fitting such as a lifting anchor or ferrule adapted to be cast into a reinforced concrete component, the shoe serving, in use, to locate tie-in bars relative to the fitting. The shoe comprises a body portion slidably received on a shank of the fitting, and clips for engaging with a snap-in action tie-in bars extending at opposite sides of the shank. The shoe can be retro-fitted to a pre-existing anchor assembly comprising an anchor, support, and void former.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to fittings adapted to be incorporated into concrete components during casting thereof. 
     2. Description of the Prior Art 
     In the fabrication of certain reinforced concrete components for use in building construction it may sometimes be necessary to incorporate within the structure of the concrete component during casting, a fitting such as an internally-threaded ferrule for forming a subsequent fixing point within the component or a lifting anchor which forms a lifting point for attachment of components of a lifting system used in the erection of the component. In one form, the ferrule or anchor is carried by a support chair which rests on the base of formwork for the concrete component, with the ferrule or anchor extending upwardly from the chair. The assembly consisting of the support chair with the ferrule or anchor is tied into the reinforcement using short lengths of reinforcing bar. When the concrete is subsequently poured into the formwork the assembly of the support chair and ferrule or anchor is incorporated within the structure of the concrete component and is firmly retained due to the tie bars which link the assembly to the main reinforcement of the component. The applicants have now determined that a difficulty can arise in that interaction between the tie bars and the shank of the ferrule or anchor sometimes can cause the tie bars to lift the assembly off from the base of the formwork if, as not infrequently happens, an operator happens to step on the reinforcement prior to casting. This in turn may mean that the head of the ferrule or anchor is no longer at the correct distance from the face of the component formed by the base of the formwork and also the assembly consisting of the support chair and ferrule or anchor may tilt relative to the lower face of the formwork. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a shoe for use with a fitting such as a lifting anchor or ferrule adapted to be cast into a reinforced concrete component, said shoe serving, in use, to locate tie-in bars relative to the fitting and comprising a body portion adapted to be slidably received on a shank of the fitting, and means for engaging tie-in bars extending at opposite sides of the shank. 
     In a preferred embodiment of the invention the engaging means comprises one or more clips for engagement with the tie-in bars. 
     Advantageously, the clips are arranged to couple with the tie bars with a snap-in engagement. 
     The present invention also provides an assembly consisting of a support for resting on the base of formwork for said component, a said fitting carried by the support so as to be upstanding therefrom, and a said shoe slidably mounted on the shank of the said fitting for engagement with tie-in bars of the reinforcement. 
     Advantageously, the fitting carries at its lower end a transverse shear pin and the shoe is mounted on the shank above the shear pin. 
     When the said fitting is a lifting anchor, the assembly preferably also consists of a void former mounted on the head of the anchor, with the shoe being movable along the shank of the anchor between the void former and support. 
     The invention also provides a said shoe for retro-fitting onto a lifting anchor assembly comprising the support, the anchor, and a void former attached to the head of the anchor, said shoe being in the form of two or more parts which can be assembled around the shank of the anchor or said shoe being of one-piece split construction which enables the shoe to be fitted onto the shank by opening the shoe to permit passage over the shank. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which: 
     FIG. 1 is a perspective view showing a lifting anchor assembly tied into reinforcement of a concrete component being cast, using a locating shoe in accordance with a preferred embodiment of the invention; 
     FIG. 2 is a perspective view of the locating shoe. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1 of the accompanying drawings an anchor assembly for use in so-called face-lifting of a concrete component comprises a support chair or stand  2  which rests on the base of formwork and a lifting anchor  4  carried by the support chair  2 . At its lower end the anchor  4  is apertured to receive a transverse shear pin  6  which extends to both sides of the anchor  4 . The shear pin  6  is located within the support chair  2  and after casting of the component forms a primary element of the securement of the anchor  4  within the component. At its upper end the anchor carries a void former  8  which remains in situ during casting. The void former  8  is removed after casting to form within the upper surface of the cast component a recess for receipt of a part of the concrete lifting system, such as a lifting clutch, which co-operates with a lifting eye at the upper end of the anchor. Thus far the anchor assembly as described is substantially conventional. The anchor assembly is tied into the mesh reinforcement  10  of the component by tie bars  12  which pass either side of the shank of the anchor  4  transversely to the axis of the shear pin  6 , the opposite ends of the tie bars  12  being connected to the adjacent reinforcing bars  10   a  by wire ties (not shown). 
     In accordance with the invention, the tie bars  12  are correctly located relative to the shank of the anchor  4  by a shoe  14  which is slidably mounted on the shank of the anchor  4  so that vertical displacement of the tie bars  12 , as may occur when an operator steps on the reinforcement, will cause the tie bars  12  coupled to the shoe  14  to slide along the shank of the anchor  4  without actually displacing the anchor  4 . More particularly, as shown in detail in FIG. 2, the shoe  14  is of tubular form with an internal passage  16  of a cross-section corresponding to the cross-section of the anchor shank and sized so as to be a sliding fit on the anchor shank. At each side, the shoe  14  comprises one or more zones  18  of attachment by which the shoe  14  is attached to the adjacent tie rod  12 . Advantageously these zones  18  of attachment are formed by part-cylindrical clips which engage with the tie rods  12  as a snap fit. In the form shown there are two such clips  18  at each side of the shoe  14  although it is to be understood that other arrangements are possible; for example at each side there may be only one such clip but with that clip being of a length in the axial direction of the tie rod to ensure sufficient stability of the attachment between the shoe and the tie rod. Attachment of the tie rods  12  to the shoe  14  could also be by means of attachment of a different form to that of the snap action clips shown. Part circular recesses may be formed in the lower edge of the shoe  14  to engage over the shear pin  6  when the shoe  14  is located immediately adjacent the support chair  2 . A shoe in the form described can be fabricated as a relatively simple plastics moulding. 
     The use of the sliding shoe  14  just described to locate the tie rods  12  relative to the shank of the anchor not only permits upwards and downwards movement of the tie rods  12  to take place without affecting the vertical position of the anchor  4 , but also ensures that if the anchor itself is subject to disturbance, for example if someone actually treads on the anchor, the anchor will be restrained against tilting either transversely to the direction of the tie bars  12  or in the direction of the tie bars  12  due to the constraint imposed by the co-operation between the shoe  14  and the tie bars  12 . The sliding movement of the shoe  14  on the shank of the anchor  4  also means that when the anchor assembly is being installed within the reinforcement  10 , the position of the shoe  14  along the shank of the anchor  4  will automatically self-adjust to suit the height of the reinforcement which has been set up. It also enables a single design of shoe to be used irrespective of the length of the anchor and hence irrespective of the depth of the component being fabricated. 
     In one form, the anchor assembly is supplied to the customer in assembled form consisting of the support chair  2  to which the anchor  4  is attached via shear pin  6 , a void former  8  mounted on the head of the anchor  4 , and a shoe  14  located on the shank of the anchor between the support chair  2  and the void former  8 , the shoe  14  being mounted on the anchor prior to attachment of the void former. However the shoe  14  can also be fabricated in a form which enables it to be retro-fitted to an anchor assembly consisting of support chair, shear pin, anchor and void former prior to installation of the anchor assembly. For example the shoe  14  can consist of two mating parts which can be clipped together around the shank of the anchor by application of the two parts laterally onto the shank. Alternatively and as illustrated, the shoe  14  may be of an open one-piece construction, for example a C-shaped construction with a break  20  in one of its side walls or end walls which can be opened sufficiently to enable the shoe to be pushed laterally onto the shank of the anchor with the gap then closing under the inherent resilience of the plastics material from which the shoe is fabricated. In another alternative, a shoe  14  of one-piece open construction can comprise two parts interconnected by an integral hinge which enables the two parts to be swung open to permit passage over the shank of the anchor, and after application to the shank, the two parts are closed together and then locked by mating of integral clip components carried by the two parts. 
     Although the shoe in the illustrated embodiment is designed for use with a lifting anchor, it is to be understood that a shoe constructed in accordance with the principles described could also be used with other cast-in fittings such as internally-threaded ferrules and in this latter case the internal passage of the shoe would be of a cylindrical shape to match the cross-sectional shape of the ferrule. 
     The embodiments have been described by way of example only and modifications are possible within the scope of the invention.