The present disclosure relates to a clamp lock anchor.
In particular the disclosure is concerned with a clamp lock anchor for clamping, and thus restraining, a reinforcement member during manufacture of a pre-stressed concrete component.
It is known to manufacture concrete products, for example slabs, beams, columns, wall and floor panels and other components or elements with reinforcement members such as wires, cables or rods, which are generally referred to as “tendons”. The concrete component may be formed in any number of ways.
For example, a mould or framework may be provided which defines the shape of the component to be made. Reinforcement members may be arranged in the mould, and then concrete added and laid around the reinforcement members. In some instances the reinforcement members are pre-tensioned prior to the concrete being laid around them. Hence as the concrete is formed into the shape of the component it surrounds the reinforcement tendon, sets, and thereby holds the tendon in place.
The reinforcement tendon may be made from a metal wire (i.e. a single member) or a metal strand (comprising several wires), and so it is important that at no point in the process is the tendon allowed to go slack. If it does then the concrete component will not be capable of holding the required and expected load for its design. Worse still, a sudden release of the tendon can result in the free end of the tendon moving at great speed which can cause severe damage and injury.
Hence a reliable means for clamping, and thus restraining, the tendon during the manufacturing process is highly desirable.
According to the present disclosure there is provided apparatus as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.
Accordingly there may be provided a clamp lock anchor for clamping a reinforcement member during manufacture of pre-stressed concrete component; the clamp lock anchor comprising: a barrel having: a barrel screw thread engagement feature; and a wall which defines a tapered internal cavity which extends between: a first opening with a first diameter at one end of the barrel; and a second opening at an opposite end of the cavity with a second diameter smaller than the first diameter; an end cap comprising: a head; a shoulder which extends away from the head; and an end cap screw thread engagement feature for engagement with the barrel screw thread engagement feature; a clamp assembly comprising: at least two clamp wedges which, when assembled: form a frusto-conical shaped body with a load application end at its widest end; and each wedge defining part of a through passage which provides a clamp surface for receiving the reinforcement member; the barrel, end cap and clamp assembly being configured to co-operate such that, in use: when a reinforcement member is entered in the clamp assembly; and the clamp assembly is located in the barrel cavity; the end cap screw thread is rotatable along the barrel screw thread such that the end cap shoulder transmits force to the load application end of the clamp assembly and thereby urges the clamp assembly into engagement with the barrel internal cavity walls, thereby urging the clamp wedges towards one another and clamping the reinforcement member.
The taper angle of the barrel internal cavity and the taper angle of the frusto-conical shaped body may be substantially the same as each other.
The at least two clamp wedges may be biased towards one another by a resilient member.
The resilient member may be located towards one end of the clamp wedges.
The resilient member may be a band or resilient material. The resilient member may be located in a groove provided in the barrel.
The clamp assembly through passage may be provided with at least one tooth which extends radially inwardly so as to engage with a reinforcement member located in the clamp assembly through passage.
The clamp lock anchor may comprise two barrels of substantially similar design; two clamp assemblies of substantially similar design, and wherein the end cap comprises: two shoulders, one shoulder extending away from one side of the head, the other shoulder extending away from an opposite side of the head; and two end cap screw thread engagement features; the barrels, end cap and clamp assemblies being configured to co-operate such that, in use: a first reinforcement member is entered in one of the clamp assemblies, and a second reinforcement member is entered in the other clamp assembly; one of the clamp assemblies is located in one barrel cavity, and the other clamp assembly is located in the other barrel cavity; one of the end cap screw threads is rotatable along one of the barrel screw threads; and the other end cap screw thread is rotatable along the other barrel screw thread; such that each of the end cap shoulders transmits force to the load application end of the respective clamp assembly; and each of the clamp assemblies is urged into engagement with its respective barrel internal cavity walls, thereby urging the clamp wedges of each clamp assembly towards one another and clamping its respective reinforcement member to thereby link the two reinforcement members.
There may also be provided a reinforcement member pre-loading apparatus comprising a clamp lock anchor according to the present disclosure.
There may further be provided a pre-stressed concrete component manufacturing apparatus comprising a reinforcement member pre-loading apparatus according to the present disclosure.
Hence there is provided a clamp lock anchor for restraining a reinforcement member, and thus maintaining tension in a reinforcement member, a reinforcement member pre-loading apparatus and a pre-stressed concrete manufacturing apparatus comprising a clamp lock anchor of the present disclosure, which will reliably grip a reinforcement member prior to, and during, the forming and curing of a concrete component.
Examples of the present disclosure will now be described with reference to the accompanying drawings, in which:
There is also provided a reinforcement member pre-loading apparatus 102 which comprises plates (or “posts”) 108, 110 spaced apart from one another and disposed at either end of the framework 12. The plates 108, 110 are part of a rigid structure for holding tendons 100 during a concrete product manufacturing process. The plates 108, 110 may be attached to a superstructure which allows for them to maintain their relative position and orientation as it is important the tendons 100 are held in place and at the desired tension.
In the example shown in
In both examples anchors 120 according to the present disclosure are provided at either ends of the reinforcement member to hold it onto the plates 108, 110 and thus maintain the position and tension in the reinforcement members/tendons 100. Additionally an alternative design of anchor 124 according to the present disclosure may be provided along the length of the apparatus 102 where it may be required to join lengths of reinforcement members/tendons 100 together, for example, joining two lengths of tendon to create a longer tendon.
Jacks (or “rams”), shown as arrows “20” in
As shown in
As shown in
In an alternative example, shown in
As shown in
Alternatively, and as shown in
As stated above, the reinforcement member/tendon 100 extends through the volume to be filled by concrete (e.g. the component 130 shown in
The clamp assembly 300 may comprise two or more clamp wedges 302, 304. For example depending on the shape or surface profile of the reinforcement member/tendon 100 to be clamped, it may be beneficial to have three clamp wedges 302, 304 which, when assembled, form the frusto conical shaped body 306.
The frusto-conical shaped body 306 is provided with a load application end 308 at its widest end. When assembled, the two or more clamp wedges 302, 304 also define a through passage 310 which provides a clamp surface for receiving a reinforcement member/tendon 100 as shown in
The clamp wedges 302, 304 are biased towards one another by a resilient member 312. The resilient member 312 may be provided at one end of the clamp wedges 302, 304. That is to say, the clamp wedges 302, 304 may be biased towards one another by a resilient member 312 at one end of the clamp wedges 302, 304. Hence, the clamp wedges 302, 304 are pivotable relative to one another, such that the clamp wedges 302, 304 can be angled relative to one another, coming together at the end where they are biased together by the resilient member 312. The resilient member 312 also allows for the clamp wedges 302, 304 to be spaced apart from one another along their entire length. The resilient member 312 may be located in a groove 314, and the groove 314 may be provided towards one end of the clamp wedges 302, 304. The resilient member 312 may be provided as a band of resilient material. For example, the resilient member 312 might be a ring of rubber or the like, for example an O-ring.
The through passage 310 may be provided with at least one tooth 316, for example provided as ribs or a screw thread on the inner surface of the passage 310 which extend radially inwards. That is to say, the at least one tooth 316 may extend radially inwardly towards the centre of the through passage 310 so as to engage with a reinforcement member/tendon 100 located in the through passage 310.
The clamp lock anchor 120 further comprises an end cap 320 as shown in
The angle of the internal cavity 204 and the angle of the frusto-conical shaped body formed by the clamp assembly 300 are substantially the same as each other. That is to say, the profile of the outer surface of the clamp assembly 300 is complementary in shape to the internal profile of the barrel 200. Put another way, the taper angle of the internal cavity 204 and the taper angle of the frusto-conical shaped body 300 are substantially the same as each other.
The geometries of the barrel 200, end cap 320 and clamp assembly 300 are configured such that the parts may co-operate to clamp a reinforcement member/tendon 100. That is to say, and as shown in
Since the end cap shoulder 324 is configured to be direct contact with the clamp assembly 300, or at least in direct force communication with the clamp assembly 300, every unit of length travelled by the end cap 320 translates into a clamping force induced between the clamp surfaces of clamp wedges 302, 304.
With reference to the example of
As the end cap 320 is screwed into the barrel 200, the end cap shoulder 324 of the end cap 320 is forced towards and transmits force to the load application end 308 of the clamp wedges 302, 304 to push the clamp assembly 300 in the direction shown by arrow B in
Thus the wedges 302, 304 and clamp teeth 316 are urged towards one another to grip and clamp the reinforcement member/tendon 100.
The alternative (double ended) clamp lock anchor 124 shown in
The first threaded region 326a is rotatable along the first internal screw thread engagement feature 210a and the second threaded region 326b is rotatable along the second internal screw thread engagement feature 210b such that each of the end cap shoulders 324a, b directly transmits force to the load application ends 308a, 308b of their respective clamp assemblies 300a, b, as discussed above for the clamp lock anchor 120. Consequently, each of the clamp assemblies 300a, b is urged into engagement with its respective barrel internal cavity walls, thereby urging the clamp teeth of each clamp assembly 300a, b towards one another and clamping its respective reinforcement member/tendon 100a, 100b to thereby link the two reinforcement members/tendons 100a, 100b. That is to say, the clamp wedges 302, 304 at each end of the clamp lock anchor 124 are forced into engagement with the internal walls of their respective barrel cavity, and thus are forced into engagement with their respective reinforcement members/tendons 100a, 100b, thereby providing a means to robustly link reinforcement members/tendons 100a, 100b together.
The direct contact and/or force transmission between the end cap and clamp assembly of both examples of clamp lock anchor 120, 124 allows for an initial clamp force to be set by a user which is predictable and positive in that once a certain force has been applied to the end of the clamp assembly 300, the clamp wedge 302, 304 cannot open any further. Hence a user knows that having clamped the reinforcement member/tendon 100, 100a, 100b by a device of the present disclosure, it cannot become released unless the end cap 320, 320′ is rotated relative to barrel(s) to which it is engaged and hence slacken off the clamp wedges 302, 304.
Having been initially clamped by a user, once tension is applied to the reinforcement member/tendon 100, 100a, 100b, the clamp wedges 302, 304 are inherently drawn into their respective barrels 200, thereby increasing the clamping force on the reinforcement member(s)/tendon(s) 100, 100a, 100b.
Since the clamp lock anchors 120, 124 of the present disclosure are configured to grip a reinforcement members/tendons 100, 100a, 100b (for example a metal wire or metal strand comprising a plurality of wires to form a tendon), they may be used in conjunction with any suitable reinforcement member pre-loading apparatus, which may in turn be used in conjunction with any suitable pre-stressed concrete manufacturing apparatus.
There is thus provided a clamp lock assembly 120, 124 which provides a positive lock on a reinforcement member/member 100, 100a, 100b. The direct contact and/or force transmission between the end cap shoulder 324, 324a, 324b of the end cap 320, 320′ and the clamp wedges 302, 304 means there is provided a constant clamping force on the reinforcement member/tendon 100, 100a, 100b. The clamp wedges 302, 304 cannot become unclamped from the reinforcement member/tendon 100, 100a, 100b unless the end cap 320 is slackened off.
Hence, when the concrete has set around the reinforcement member/tendon 100, a user may slacken the connection between the end cap 320, 320′ and associated barrel 200, 200a, 200b, and thus withdraw clamp wedges 302, 304 and barrel 200, 200a, 200b from the reinforcement member/tendon 100, 100a, 100b. Thus the clamp lock anchors 120, 124 of the present disclosure may be re-used.
Additionally because of the simplicity of design of the clamp lock anchor 120, 124 of the present disclosure, when the clamp lock anchor 120, 124 is cleaned, it is relatively easy to inspect and test. Only the resilient member 312 may need to be replaced on a regular basis.
Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
Number | Date | Country | Kind |
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1508519.4 | May 2015 | GB | national |