GB2137252A

GB2137252A - Spacer for reinforcement mats

Info

Publication number: GB2137252A
Application number: GB08308819A
Authority: GB
Inventors: Selma Dreizler
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-03-30
Filing date: 1983-03-30
Publication date: 1984-10-03
Also published as: GB8308819D0

Abstract

A spacer for holding reinforcement mats in shuttering or formwork comprises a spacer bar 1 and at least one clip 3 adapted to engage a bar 10 of a reinforcement mat. The clip 3 is a flat plate 5 with a U-shaped opening 6 defined by two arms 7, 8. It is welded to the spacer bar 1 adjacent the bottom of the opening 6. A resilient closing element 11 is anchored to one arm 8 and projects into the opening 6. It is resiliently deformable towards the arm 8 to allow insertion of a mat bar 10, but abutment on the opposite arm 7 resists removal of the bar 10. The plate construction allows secure attachment to the spacer bar 1 by spot-welds 4. <IMAGE>

Description

SPECIFICATION Spacer for reinforcement mats The invention relates to a spacer for holding reinforcement mats in a formwork.

Such spacers are used for example in the case of vertical reinforcements for holding two reinforcement mats at a specific distance apart and ensuring that the reinforcement mats in their turn are situated at the correct spacing from formwork panels. In a constructional form known from German Utility Model 7 732 466 two U-shaped clips of spring steel are secured on a spacer bar at a predetermined spacing from the two ends. The bar .has plastic caps on the ends. The spacer is located with these clips on appropriate bars of the two reinforcement mats which are to be held spaced. To prevent loss, the ends of the wire clips are bent over inwardly, so that a resilient closing arrangement is produced which closes the aperture formed by the two arms of a clip in each case.

These spacers have been found to be extremely satisfactory in practice, but their loadaccepting ability is limited, since the arms of the wire clips may be bent open when relatively considerable forces are acting. This could only be prevented by increasing the wire diameter. This however, can only be done to a certain degree. Also, the wire clips are secured by spot welding to the spacer bar, which is made from inexpensive non-alloyed carbon steel or structural steel. But this kind of simple connection is possible only for clips made of a material whose diameter is not too large. More complicated welding methods are not practicable, if only because the spacers are used in large numbers and have to be produced cheaply.

According to the present invention there is provided a spacer for holding reinforcement mats in formwork, comprising a spacer bar and at least one clip secured thereto; the or each said clip comprising a flat plate having arms which delimit a substantially U-shaped opening for receiving a reinforcement mat bar; said clip having an elastic closing element for holding the clip captive on a reinforcement mat bar, said closing element comprising a resilient element which is anchored to one arm of the plate and which projects so as to close off the opening at least partly; said element being resiliently deformable towards said one arm. Preferably each clip is secured to a spacer bar adjacent the bottom of its opening.

A spacer embodying the invention may be producible cheaply and rationally, and be able to withstand even relatively considerable forces acting on the clips without thereby prejudicing the manipulation thereof.

The clip comprises a flat plate, which can be produced cheaply as a simple stamping. If its dimensions are chosen suitably, such a plate is extremely stable, so that the arms delimiting its U-shaped opening or aperture cannot be pressed to the side even when subjected to relatively considerable forces.

The plate and the spacer bar usually consist of a simple non-alloyed carbon steel or structural steel, the plate being welded to the spacer bar. A relatively large welding surface is available, for example as compared to a wire stirrup, and this in its turn permits a very stable welded connection without having to take special precautions in order to achieve this. The welding conditions for connecting the spacer bar to the plate, which can consist of substantially the same material, are also substantially more advantageous than would be the case with having to weld a spring steel stirrup to a spacer bar made of non-alloyed carbon steel or structural steel.

In a preferred constructional form the resilient or elastic element is a spring tongue which is resiliently movable. It is anchored at one end to an arm and projects with its free end into the opening. This prevents accidental removal of the clip from the associated reinforcement bar. The spring tongue, which is directed obliquely towards the bottom portion of the U-shaped opening is adapted to bear at its free end on the opposite arm, so as to provide a shape-locking closing arrangement for the opening. For the same reason the arrangement may also be such that the free end of the spring tongue is adapted to bear on a nose at the other arm.

The spring tongue may be formed of a plate spring, but it is also possible to make it in the form of a wire spring. The second-mentioned constructional form is cheaper and could be considered more especially for spacers intended for use with reinforcement mat bars of large diameter.

In a further constructional form the spring tongue may be cut from a spring plate piece which is secured by means of holding portions to the associated arm of the clip. But constructional simplicity is also obtainable if the spring tongue is anchored with a suitably shaped end portion non-losably in a holding aperture of the associated arm and in such a manner as to be capable of being bent in one direction, and is fixed laterally by material of the plate.

To ensure that the spacer is seated particularly accurately on the reinforcement bars, the spring tongue can comprise a holding portion which is bent towards the bottom of the Ushaped opening and which holds the reinforcement bar in abutment against the bottom of the opening. In a further constructional form this can be achieved in that the spring tongue is formed by a side portion of a strip of spring material bent to substantially triangular shape which, with its base portion, is inserted in a holding aperture provided in the associated arm and surrounding said portion on both sides, and whose other side portion is the holding portion.

More particularly when using a spring tongue consisting of round-section wire it is advantageous if the plate consists of two mirrorimage plate portions which are arranged with their wide sides on one another and are connected to one another and between which the spring tongue is held, and which delimit, in the region of the arm associated with the spring tongue, a niche-like recess directed towards the U-shaped aperture and accommodating the spring tongue when bent to the side.

A spacer will usually have two clips in the form of plates of the kind discussed which are in each case situated at a specific spacing from its end. But it is also conceivable to have only one clip on the spacer bar, e.g. at the centre. As already mentioned, the plates themselves are usually made preferably from an unalloyed simple carbon steel or structural steel.

Some embodiments of the invention will now ve desribed with reference to the drawings wherein: Fig. 1 shows a part of a spacer according to a first embodiment of the invention in side view, partly in section; Fig. 2 shows a spring plate piece of the spacer according to Fig. 1, in perspective view; Fig. 3 shows a spacer according to a second embodiment in a view similar to Fig. 1; Fig. 4 shows a detail of the clip of the spacer according to Fig. 3, in section along the line IV-IV of Fig. 3, in a plan view, Fig. 5 shows a spacer according to a third embodiment in a view similar to Fig. 1; Fig. 6 shows a spacer according to a fourth embodiment, in a side view sectioned along the line VI-VI of Fig. 7; and Fig. 7 shows the spacer of Fig. 6 in an end view taken on the line VII-VII of Fig.6.

The spacer shown in various constructional forms in the drawings comprises in each case a cylindrical spacer bar 1 which is made of an unalloyed carbon steel and which at each of its two ends is fitted with a small cap, shown in section at 2, of synthetic plastic material or a cement-tolerating material, and on which there are secured at a pre-determined distance from the ends two clips 3 of which only one in each case, however, is shown in Figs. 1, 3, 5, 6, and 7, for the sake of simplicity.

In all the constructional forms each of the clips 3 is made in the form of a flat plate 5 from an unalloyed carbon steel. The plate 5 is welded to the spacer bar so as to abut with a side face against said bar. The spot welds are indicated at 4 (Fig. 1).

Each plate 5 has a substantially U-shaped opening or aperture 6 which is open at the edge and is delimited by two arms 7, 8 of the plate 5 and whose bottom portion 9 is curved in accordance with the diameter of a bar of a reinforcement mat as shown in broken lines at 10, on to which the corresponding clip 3 of the spacer is placed. The U-shaped aperture 6 has associated with it an elastic closing element which prevents accidental release of the clip 3 from the reinforcing bar 10.

In the constructional form shown in Fig. 1, this closing element is formed of a spring tongue 11 cut from a substantially rectangular spring plate piece 12 shown in Fig. 2. The spring plate piece 1 2 comprises laterally angled-over holding claws 13; it is placed inside on the arm 8 of the plate 5 in the way shown in Fig. 1, and locked by means of the holding claws 1 3 engaging into corresponding recesses of the plate 5, bearing, in so doing, axially on a shoulder 14 of the arm 8.

As Fig. 1 shows, the spring tongue 11 projects from the vicinity of the end of the arm 8 obliquely in the direction towards the bottom portion 9 of the U-shaped aperture 6, into this aperture, and its free end bears-at 1 5-on the opposite arm 7.

When the clip 3 is placed on the reinforcement bar 10, therefore, the spring tongue 11 which is mounted to be elastically movable at its anchoring point on the arm 8 can yield laterally towards the arm 8. As the reinforcement bar 10 approaches the position shown in Fig. 1 the spring tongue snaps back into the position shown in this figure, wherein the U-shaped aperture 6 is closed. Since the spring tongue 11 is supported at 1 5 on the arm 7, as already mentioned, the aperture 6 is closed in locking manner; the spring tongue 11 can accept considerable forces in the closing direction.

In the constructional form shown in Figs. 3 and 4 the arrangement is such that the arm 8 of the plate 5 comprises in the vicinity of its end a through hole 1 6 into which the cylindrically rolled end portion 1 7 of the spring tongue 11 a enters, said tongue being also constructed as a plate spring, and the spring tongue 11 a itself projects through a slot 18 into the U-shaped aperture 6. The slot edge is rounded-off at 19, so that the spring tongue 11 a can yield to the side in the direction of insertion of the reinforcement bar 10 (in Fig.

3 in the clockwise direction). To hold the end portion 1 7 of the spring tongue 11 a captive in the hole 16, impressions 20 are formed in the arm 8 so that the spring tongue 11 a is axially secured by the material of the plate 5.

Constructed on the opposite arm 7 is a nose 21 on which the end 1 5 of the spring tongue 11 a can come to bear in the blocking or closing direction, so that the U-shaped aperture 6 is closed in the manner already explained, and the clip 3 is held captive on the reinforcement bar 10.

In the constructional form shown in Fig. 5 the arrangement is such that the elastic ele ment 22, constructed as a plate spring, is bent to a substantially triangular shape from a spring steel strip. One side portion 11 b of the spring material strip 22 forms the spring tongue projecting into the U-shaped aperture 6 and adapted to bear with its free end 1 5 in the closing direction on a nose 21 of the arm 8. The base portion 23 of the spring material strip 22 bent to triangular shape is inserted into a corresponding holding cavity 24 of likewise approximately triangular shape which is open towards the U-shaped aperture 6 and which extends at the sides about the base portion 23 in the manner shown in Fig. 5.

The other side portion 25 of the spring material strip 22 is bent over to form a semicircular holding portion 26 which is curved towards the bottom portion 9 of the U-shaped aperture 6, and holds the reinforcement bar 10 elastically abutting on the bottom portion 9 of the U-shaped opening 6.

The holding portion 26 and the spring tongue 11 b can yield to the side when the holder 3 is placed on the reinforcement bar 10, so that the handling of the spacer is not prejudiced in any way.

Finally, Figs. 6 and 7 show a constructional form of the new spacer wherein the plate 5 comprises two mirror-image plate portions 5a, 5b which lie with side faces on one another and which are connected to one another by spot welding at 27. Between the two plate portions 5a, 5b, a spring tongue 11 c consisting of round-section wire material is anchored with a bent-over end 28 in the region ot the end of the arm 8. The spring tongue 1 1c projects in the manner shown in Fig. 6 into the U-shaped aperture 6; it comprises a holding portion 26 bent over towards the bottom portion 9 of the U-shaped aperture 6 and holding the reinforcement bar 10 in abutment on the bottom portion 9 of the aperture 6 in the manner already explained in connection with Fig. 5.Again a nose 21 is provided on the opposite arm 7, against which the spring tongue 1 1c can bear in the closing direction.

Between the two plate portions 5a, 5b there is defined a niche-like recess 30 which is open towards the U-shaped aperture 6 and which, when the holder 3 is put on to the reinforcement bar 10, receives the spring tongue 11 c when the latter yields laterally, whereat the holding portion 26 of the said tongue enters a portion of suitable depth 31 of the recess 30.

More particularly the constructional form shown in Figs. 5 and 6 is intended for relatively thick reinforcement bars 10. To provide some idea of the dimensions of the plate 5, it may be mentioned that with a diameter of reinforcement bar 10 of approx. 10 mm the plate 5 has a length of approx. 30 to 45mm in the longitudinal direction of the spacer bar 1 and -at right angles thereto height of approx. 30 to 60 mm and more. The thickness of the plate may be for example between 4 and 6 mm, but of course other dimensions are also possible, depending on the stresses which are to be expected in each particular case.

Claims

1. Spacer for holding reinforcement mats in formwork, comprising a spacer bar and at least one clip secured thereto; the or each said clip comprising a flat plate having arms which delimit a substantially U-shaped opening for receiving a reinforcement mat bar; said clip having an elastic closing element for holding the clip captive on a reinforcement mat bar, said closing element comprising a resilient element which is anchored to one arm of the plate and which projects so as to close off the opening at least partly; said element being resiliently deformable towards said one arm.

2. A spacer according to claim 1 wherein each said clip is secured to the spacer bar in the region of the bottom of the U-shaped opening.

2. A spacer according to claim 1 wherein the or each said clip is secured to the spacer bar in the region of the bottom of the Ushaped opening.

3. Spacer according to claim 1 or 2 wherein the resilient element comprises a spring tongue which is anchored at one end to a first one of the said arms of the plate, and which projects into the U-shaped opening.

4. Spacer according to claim 3, wherein the spring tongue extends obliquely towards the bottom portion of the U-shaped opening and is arranged to bear with its free end on the second arm.

5. Spacer according to claim 3 or 4 wherein the second arm has an abutment against which the spring tongue is arranged to bear with its free end.

6. Spacer according to any preceding claim, wherein the resilient element is formed of a plate spring.

7. Spacer according to any of claims 1 to 5, wherein the resilient element is formed of a wire spring.

8. Spacer according to claim 6, wherein the resilient element is cut from a spring plate piece which is formed with holding portions by means of which it is secured to said one arm of the clip.

9. Spacer according to any of claims 1 to 7 wherein the resilient element is anchored with a suitably shaped end portion in a holding aperture in said one arm so as to be capable of being bent over in one direction; and wherein the plate is shaped to resist lateral displacement of the element.

10. Spacer according to any preceding claim, wherein the resilient element comprises a holding portion which is bent towards the bottom of the U-shaped opening and which in use acts to hold a mat reinforcement bar in abutment against the bottom of the opening.

11. Spacer according to claim 10 wherein the resilient element comprises a strip of spring material bent to a substantially triangular shape whereof (i) a side portion provides a resiliently deformable tongue, (ii) a base portion is inserted in a holding aperture which is provided in said one arm of the plate and which surrounds said base portion on both sides; and (iii) the other side portion provides said holding portion.

12. Spacer according to claim 7, wherein the plate comprises two mirror-image plate portions (5a, 5b) which overlie one another and are mutually connected, and between which the resilient element is held; the plate portions being arranged to define in said one arm a recess opening towards the U-shaped opening for accommodating the resilient element when this is bent in the direction of the arm.

1

3. Spacer according to any preceding claim wherein the plate and the spacer bar are made from unalloyed carbon steel or structural steel, and are welded to one another.

14. A spacer substantially as described herein with reference to and as illustrated in Figs. 1 and 2, or Figs. 3 and 4, or Fig. 5, or Figs. 6 and 7 of the accompanying drawings.

1 5. A clip for use as a said clip in a spacer according to any preceding claim.

1 6. Formwork including reinforcement mats held by at least one spacer according to any preceding claim.

1. Spacer for holding reinforcement mats in formwork, comprising a spacer bar and two clips secured thereto near its ends; each of said clips comprising a flat plate having arms which delimit a substantially U-shaped opening for receiving a reinforcement mat bar; each clip having an elastic closing element for holding it captive on a reinforcement mat bar; said closing element comprising a resilient element which is anchored to one of the plate and which projects so as to close off the opening at least partly; said element being resiliently deformable towards said one arm.