Anchor

Abstract

An anchor 10 e.g. for casting into a concrete ceiling for clamping an elongate article therein, the anchor having a main part 14 defining a passage 16 with converging wall regions (28, Fig. 2) and 1st

Description

This invention relates to anchors. This invention may also relate to anchors for use in upper supports, such as ceilings. More specifically, but not exclusively, this invention relates to concrete anchors. Embodiments of the invention relate to anchors that can be embedded in concrete. Anchors to secure items, such as cable trays or pipework, to ceilings are known. Such anchors are often referred to as cast in place anchors. The anchor is arranged on a support, known as a deck. Concrete is poured over the deck to form the ceiling, the anchor is thus embedded in the concrete. After the concrete has cured, the deck is removed or left in place. A threaded rod is inserted into the anchor through an opening in the underside of the anchor and through an aperture in the deck if it has been left in place. The threaded rod is screwed into the anchor from below to secure the rod to the anchor. According to one aspect of this invention, there is provided an anchor comprising: a main part defining a passage to receive an elongate article; first and second clamp members arranged in the passage to receive the article therebetween; wherein the passage has a converging wall region, and movement of the first and second clamp members along the passage in the direction of the inward convergence of the wall region urges the clamp members towards each other. According to another aspect of this invention, there is provided a connector comprising: a clamp member movable between a clamping condition and a release condition; wherein when the clamp member is in the clamping condition, an elongate article received between the clamp member and a further part of the connector is clamped by the clamp member, thereby securing the elongate member to the connector; wherein the clamp member comprises clamping formations configured to clamp elongate articles of different diameters. According to another aspect of this invention, there is provided a connector comprising: first and second clamp members; the first clamp member being movable relative to the second clamp member between a clamping condition and a release condition; wherein when the first and second clamp members are in the clamping condition, an elongate article received between the first and second clamp members is clamped by the first and second clamp members thereby securing the elongate article to the connector; wherein each clamp member comprises clamping formations configured clamp elongate articles of different diameters. According to another aspect of this invention, there is provided an anchor arrangement comprising an anchor as described above, and first and second elongate articles, a selected one of which is secured to the anchor, wherein each clamp member has a contact surface to contact the elongate article, and each clamp member comprises a plurality of securing formations on the contact surface to secure the elongate article to the anchor, the securing formations being spaced from each other by a distance that allows the securing formations to be received between corresponding formations having a first pitch on the first elongate article, and between corresponding formations having a second pitch on the second elongate article, wherein the first pitch differs from the second pitch, and wherein when the first elongate article is selected, the securing formations are received between the corresponding formations of the first article and, when the second elongate article is selected, the securing formations are received between the corresponding formations of the second article. The anchor arrangement may comprise a third elongate article, wherein the securing formations are spaced from each other by a distance that allows the securing formations to be received between corresponding formations having a third pitch on the third elongate article, whereby when the third elongate article is selected, the securing formations are received between the corresponding formations of the third article. The securing formations comprise a plurality of spaced elongate projections extending across the contact surface. The clamp members are urged towards the elongate article by the inwardly converging wall region into clamping engagement with the elongate article. The anchor may be a concrete anchor. The anchor may be a ceiling anchor. The anchor may be a cast in place anchor, which may be a cast in place ceiling anchor. The elongate article may be a rod, which may be substantially cylindrical. The elongate article may be a threaded rod. An end region of the article may be received in the passage. The first and second clamp members may be movable together along the passage in the direction of the inward convergence of the wall region. The anchor may include a third clamp member. The third clamp member may be movable along the passage in the direction of the inward convergence of the wall region. The first, second and third clamp members may be movable together along the passage in the direction of the inward convergence of the wall region. The elongate article may be clamped between the first, second and third clamp members. The clamp members may define a central space therebetween through which the elongate article can extend. The clamp members may extend around the central space. The clamp members may extend in an annular configuration around the central space. Each clamp member may have a contact surface to contact the elongate article. The contact surface may be a concave surface. Each clamp member may comprise a securing formation on the contact surface to secure the elongate article to the anchor. The securing formation may be elongate and may extend across the contact surface. Each clamp member may comprise a plurality of the securing formations, which may be spaced from one another. The securing formations may be spaced from each other by a distance that allows the securing formations to interact with corresponding formations of the elongate article. Each securing formation may be elongate and may extend across the contact surface. The securing formations may be spaced from each other by a distance that allows the formations to interact with corresponding formations of first and second elongate articles. The first and second elongate articles may be first and second elongate articles of different sizes. The securing formations may be spaced from each other by a distance that allows the securing formations to be received either between corresponding formations having a first pitch on a selected first elongate article, or between corresponding formations having a second pitch on a selected second elongate article. The pitch of a formation may be the distance between the same point on adjacent crests of the formation. The corresponding formations of the first elongate article may comprise first threads. The corresponding formations of the second elongate article may comprise second threads. The securing formations may be spaced from each other by a distance that allows the formations to interact with corresponding formations of first and second elongate articles. The first and second elongate articles may be first and second elongate articles of different sizes. The first elongate article may be a first threaded rod. The second elongate article may be a second threaded rod. The corresponding formations of the first threaded rod may be first threads. The corresponding formations of the second threaded rod may be second threads. The first threads may have a different pitch from the second threads. The first threaded rod may have a smaller diameter than the second threaded rod. In such a circumstance, the first pitch may be less than the second pitch. The securing formations may comprise a plurality of spaced elongate projections extending across the contact surface. The projections may comprise ridges. The projections may be elongate. The projections may be helically oriented along the contact surface. The projections may be helically oriented around the longitudinal axis of the concavity. The projections may be spaced from each other by a distance to allow the projections to be received by corresponding formations of the elongate article. The projections may be spaced from each other by a distance to allow the projections to be received by corresponding formations of the first or the second elongate articles. The first thread may have a first pitch. The second thread may have a second pitch. The pitch of a thread is considered to be the distance between adjacent ridges of the thread. The spacing between adjacent formations of the clamp member may be approximately equal to a first multiple of the first pitch and to a second multiple of the second pitch. Thus, the clamp member may clamp either the first elongate article or the second elongate article by the formations interacting with corresponding formations of either the first elongate article or the second elongate article. In one embodiment, the formations may comprise elongate projections, and the clamp member may clamp either the first elongate article or the second elongate article by the elongate projections interacting with first thread of the first elongate article or with the second thread of the second elongate article The spacing of adjacent elongate projections may allow the projections to be received either in a groove of the first thread of the first threaded rod, or in a groove of the second thread of the second threaded rod. Thus, the gripping member can grip either the first threaded rod or the second threaded rod. Each clamp member may have two of the elongate projections. The elongate projections may be spaced from each other along the contact surface by the aforesaid spacing. Alternatively, the clamp member may have three of the elongate projections. Each elongate projection may be spaced from each adjacent elongate projection by the aforesaid spacing. Each clamp member may have an outer surface. The outer surface may be opposite the contact surface. The anchor may comprise a band. The band may be annular and may extend around the clamp members. Each outer surface may define a groove for receiving the band. The band may be elongate. The band may be a flexible member, which may formed of an elastomeric material or may be a wire. The anchor may further comprise a carriage for carrying the clamp members. The carriage may have opposite retainers. The carriage may have a respective retainer at each of the opposite ends. The clamp members may be disposed between the retainers. The clamp members may be retained on the carriage by the retainers. Each retainer may be substantially circular. Each retainer may be substantially annular to allow the elongate article to extend therethrough. The carriage may further include elongate connectors to connect the retainers to each other. The carriage may comprise three of the connectors. Each clamp member may be arranged between adjacent connectors. Each connector may define a groove to receive the band. Each connector may have an outer edge. The outer edge may define the connector’s groove. The grooves defined by the connectors may be aligned with the grooves defined by the clamp members. The main part may comprise a housing in which the carriage and the clamp members are housed. The main part may include a collar extending around the housing. The collar may extend around an upper end of the housing. The collar may extend around the wall region. Desirably, the collar may extend around the wall region at the upper end of the housing. The housing may have a cylindrical configuration. Alternatively, the housing may have a frustoconical configuration. The collar may extend circumferentially around the housing. The main part may define the passage. Optionally, the housing defines the passage. The main part may define a first opening to provide communication between the passage and a region external of the main part. The first opening may be a lower opening. Optionally, the housing defines the first opening. The elongate article may extend through the first opening into the passage. The first opening may be defined in an underside of the main part. Optionally, the first opening is defined in an underside of the housing. A recess may be defined around the first opening. The anchor may further include a base part to support the main part. The base part may receive the main part. The base part may comprise a holder to receive the main part. The holder may comprise a cup portion. The housing may be received by the cup portion. In one embodiment, the base part may be devoid of the cup portion. The main part may define a second opening, which may be opposite the first opening. Optionally, the housing defines the second opening. The second opening may be an upper opening. The second opening may provide communication between a region external of the main part and the passage. The base part may comprise substantially flat portion, which may be a flange portion or a plate portion. The holder may be provided on the substantially flat portion. The holder may comprise a wall, which may be on the substantially flat portion. The wall may be an annular wall. The holder may enclose a region of the substantially flat portion. The base part may define a third opening, which may be aligned with the first opening. The third opening may be aligned with the second opening. The anchor may further comprise a cap mountable on the main part across the passage, when so mounted, the cap may extend across the second opening, thereby closing the passage at said second opening. The cap may extend across the housing. The anchor may comprise a clamping spring to bias the clamping members in the direction of the inward convergence of the wall region. The clamping spring may be a coil spring. The clamping spring may be housed in the housing. The clamping spring may extend between the clamping members and the main part. Where the anchor comprises a carriage, the clamping spring may extend between the carriage and the main part. The clamping spring may extend between the carriage and the cap. The clamping spring may extend between one of the retainers and the main part. The clamping spring may extend between one of the retainers and the cap. The anchor may comprise a tubular member. The tubular member may be provided on the main part or on the base part. The tubular member may extend from the first opening. The tubular member may be attached to the base part or to the main part. The tubular member may be integrally attached to the base part or the main part. Alternatively, the tubular member and either the main part or the base part may comprise attachments to attach the tubular member to the main part or to the base part. In one embodiment, the attachments may be provided on the tubular member and either the main part or the base part. The attachments may comprise interlocking projections on the tubular member and either the main part or the base part. The attachments may comprise inwardly extending projections on the tubular member and outwardly extending projections on the main part or the base part. An upper end region of the tubular member may receive a lower end region of the main part or the base part to allow the outwardly extending projections to interlock with the inwardly extending projections to attach the tubular member to the main part or the base part. The anchor may comprise a holder, which may receive the main part. The holder may comprise a central portion. The holder may further comprise a first end portion at a first end of the central portion. The first end of the central portion may be a top of the central portion. The first end portion may be a top end portion. The first end portion may be substantially circular. The first end portion may protrude radially outwardly. The holder may receive the housing. The holder may comprise a second end portion at a second end of the central portion. The second end of the central portion may be a bottom of the central portion. The second end portion may be a bottom end portion. The second end portion may be substantially circular. The second end portion may protrude through the base part. The holder may have an internal shape and size that corresponds with the external shape and size of the housing. The holder may comprise a conical portion in which the main part may be received. The holder may comprise a strut which may extend between the top and bottom end portions. The holder may comprise a plurality of the struts, which may be circumferentially spaced from one another around the top and bottom end portions. The holder may have a conical shape. The conical shape may be a frustoconical shape. In one embodiment, the holder may comprise a cage. The main part may be received in the cage. The cage may have a conical shape. The cage may have a frustoconical shape. The holder may comprise three of the struts. The top end portion may protrude radially outwardly beyond the struts. In another embodiment, the holder may comprise a casing to receive the main part. The casing may comprise the cup portion. The casing may have an internal shape and size that corresponds with the external shape and size of the housing. The housing may be a close fit within the casing. The casing may have a conical shape. The conical shape may be a frustoconical shape. The casing may be configured to prevent the entry of water. The casing may comprise a wall which may have a conical shape. The wall may have a frustoconical shape. The wall may be configured to prevent water passing therethrough. The wall may be devoid of apertures. The wall may be nonporous. The cap may comprise a cover portion. The casing may create a watertight seal with the cap. The cap and the casing may engage each other to create said watertight seal. The cap and the casing may be attached to each other to create said watertight seal. The top end portion of the holder may engage an edge region of the cover portion. The top end portion of the holder and the edge region of the cover portion may engage each other to create said watertight seal. The radially outwardly protruding top end portion of the holder may be attached to the edge region of the cover portion. The top end portion of the casing, and the edge region of the cover portion may be attached to each other to create said watertight seal. The cover portion may have an outer rim defining the edge region. The outer rim of the cover portion may be substantially circular. At least one of the cap and the holder may comprise a lip at which the cap and the casing may be attached to each other. The lip may be provided on the edge region of the cover portion and / or the top end portion of the holder. In one embodiment, the lip may be provided on the top end portion of the holder. The cover portion may be attached to the holder by welding, for example ultrasonic welding. The holder may be formed of a plastics material. The cap may be formed of a plastics material. The cap, the clamping spring and the carriage may be formed of a plastics material. The anchor may comprise a carriage arrangement. The carriage arrangement may comprise the carnage and the clamping spring. The carriage and the clamping spring may be integrally attached to each other. The carriage arrangement may further comprise the cap. The cap and the clamping spring may be integrally attached to each other. The carriage and the cap may be attached to the clamping spring at opposite ends of the clamping spring. When the holder receives the main part, the collar of the main part may engage the top end portion of the holder. The top end portion may support the collar. The top end portion may support the main part by engagement of the top end portion with the collar. The holder may have a top opening, which may be defined by the top end portion. The main part may be received into the holder via the top opening. The holder may have a bottom opening. The bottom opening may be defined by the bottom end portion. The holder may have an internal region to receive the main part. The tubular member may be attached to the holder. The tubular member may be attached to the holder at said bottom end portion. The tubular member may be attached to the holder at said bottom opening to provide communication between the internal regions of the holder and of the tubular member. The tubular member may be integrally attached to the holder. Alternatively, the holder and the tubular member may comprise corresponding fasteners to fasten the tubular member to the holder. The fasteners may be configured to interact with each other to fasten the tubular member to the holder. The fasteners may comprise interlocking formations. The fasteners may comprise snap fit fasteners, bayonet fittings, threads, or other suitable fasteners. The tubular member may include an elongate part and a collar extending around the elongate part. The collar may be arranged at an upper region of the elongate part. The collar may be spaced from the elongate part. The collar may be spaced radially from the elongate part. Connectors may connect the collar to the elongate part. The connectors may comprise ribs. The fasteners of the tubular member may be provided on the collar. The fasteners of the holder may be provided at the bottom end portion of the holder. The bottom opening may be aligned with the first opening to provide communication between the inside of the main part and the tubular member. Thus, the elongate article may be received into the housing by being received through the tubular member, the bottom opening and the first opening. The cap may be attached to the clamping spring. The cap may secure the main part to the holder. The clamping spring may extend between the cap and the carriage. The cap may extend over the collar of the main part. The cap may secure the collar of the housing to the top end portion of the holder. The cap may secure the collar of the main part between the cap and the top end portion of the holder. The cap may further include hooks to engage the top end portion of the holder. The hooks may extend from the cover portion. The hooks may extend from the periphery of the cover portion. Said engagement may secure the cap to the holder. The clamping spring may be integral with the carriage. The clamping spring may extend from one of the retainers. The cap may be integral with the clamping spring. The cap may define a recess into which an upper end of the elongate article can be received. The recess may be defined by a lower face of the cover portion. The elongate article may be inserted into the anchor to be received in the passage. Desirably, the elongate article is inserted into the passage to be received in the recess. The elongate article may be pulled downwardly to cause the clamp members to be urged into tight engagement with the elongate article by the inward convergence of the wall region. Where the elongate article is threaded, for example in the case of a threaded rod, the elongate article may be screwed into the main part by the interaction of the threads with the spaced projections of the clamp members. Thus, the elongate article can be screwed back into the main part until the end of the elongate article engages the cap in the recess. This engagement of the end of the elongate article with the cap provides the advantage in the embodiments described herein that lateral movement of the elongate article is reduced. In addition, there is an improvement in the performance of the anchor when the elongate article undergoes shear testing. The anchor may comprise a fastener to fasten the anchor to a support. The support may be a deck. The deck may be suitable for forming a ceiling. The support may be formed of wood or metal. The anchor may comprise an outwardly extending finger to attach the anchor to the support. The outwardly extending finger may be provided on the tubular member. The outwardly extending finger may be provided at the top of the tubular member. The anchor may comprise a plurality of the outwardly extending fingers. The anchor may include a securing spring to bias the base part and the main part away from each other. The securing spring may fasten the anchor on the support. The securing spring may be an external spring, which may be an external coil spring. The base part and the main part may be movable relative to each other to enable the fingers to engage the underside of the support, thereby securing the anchor to the support. The fingers may be formed of a resilient material. The anchor may be disposed on the support over an aperture formed therethrough. The tubular member may extend through the aperture. The tubular member may be inserted through the aperture. When so inserted, the fingers may engaged by the edge of the aperture. A downward force may be applied to main part to drive the main part downwardly relative to the base part. The downward force may drive the tubular member and the fingers through the aperture. As the edge of the aperture engages the fingers, the fingers may be pressed inwardly to allow them to pass through the aperture. When the fingers have passed fully through the aperture, the fingers may move outwardly. The securing spring may urge the main part away from the base part so that the fingers engage the underside of the deck. When so arranged, the securing spring may be under compression between the main part and the base part. Thus, the force of the securing spring may urge the fingers against the underside of the support, thereby securing the anchor to the support. The securing spring may extend between the base part and the holder. The securing spring may extend between the base part and the top end portion of the holder. Thus, the top end portion provides a reaction force on the securing spring to allow the securing spring to bias the bias the base part and the main part away from each other. Alternatively, the holder may comprise a reaction member to provide a reaction force on the securing spring. The reaction member may engage the securing spring. The reaction member may be provided in an intermediate region of the central portion. The reaction member may be provided in a region intermediate the top and bottom end portions. The reaction member may comprise a projecting tooth. A strengthening member may be provided on the reaction member. The strengthening member may be in the form of a strengthening fin. The strengthening member may extend from the reaction member along the holder The reaction member may be provided on the strut. The holder may comprise a plurality of the reaction members, which may be spaced circumferentially around the holder. Each reaction member may comprise a projecting tooth. The reaction members may be provided on the struts. Each strengthening member may extend from the respective reaction member along the strut on which the reaction member is provided. Alternatively, where the holder comprises a casing, the projecting reaction member may be of an annular configuration. The reaction member may extend around the holder, desirably circumferentially around the holder. The reaction member may extend around the casing, desirably circumferentially around the casing. A plurality of the strengthening members may be provided on the reaction member spaced around the casing. Each strengthening member may extend from the reaction member along the casing. The securing spring may extend between the base part and the, or each, reaction member. The holder may include a bottom end portion which may protrude through the base part. The anchor may have a tubular member that is a push fit on the bottom end portion. The bottom end portion may be attached to the central portion at a region of weakness. The region of weakness may be adjacent to the fingers. Where the anchor comprises a plurality of the fingers, the anchor may comprise a plurality of the regions of weakness. Each region of weakness may be between adjacent fingers. The regions of weakness may be regions of the bottom end portion that are narrower than other regions of the bottom end portion. The regions of weakness may allow the bottom end portion to be detached from the casing, for example by being struck with a hammer. The anchor may include a socket and fixing rib. The fixing rib may be received by the socket to fix the main part to the holder. The fixing rib may be a friction fit within the socket. The socket may be provided on one of the main part and the holder. The fixing rib may be provided on the other of the main part and the holder. In one embodiment, the socket may be provided on the holder and the fixing rib may be provided on the main part. The socket may be provided on the cup portion and the fixing rib may be provided on the housing. The anchor may comprise a plurality of the sockets and a corresponding number of the fixing ribs. The anchor may comprise three of the sockets and three of the fixing ribs. The, or each, socket may be elongate. The, or each, fixing rib may be elongate. The, or each, socket may defines an elongate recess, which may communicate via an elongate slot into the interior of the cup portion. The, or each, socket may be arranged between adjacent guide tubes. The, or each, socket may extend parallel to the guide tubes. The, or each, socket may define an upper opening. Where the anchor includes the carriage arrangement, the carriage arrangement and the clamp members may be received in the housing. The, or each, fixing rib may extend along the outer surface of the housing. The, or each, fixing rib may be so arranged on the housing to allow the, or each, fixing rib to be received by the, or each, socket. The, or each, fixing rib may be received through the upper opening of the, or each, socket into the, or each, elongate recess. The fastener may comprise a screw or a nail, a plurality of screws or nails, an adhesive fastener, or a magnetic fastener. Where the support is formed of wood, the fastener may comprise the screw or nail, or the adhesive fastener. Where the support is formed of metal, the fastener may comprise screws, an adhesive fastener, or a magnetic fastener. The substantially flat portion may define apertures through which the fastener, such as the nail or screw can extend to fasten the anchor to the support. The anchor may comprises a guide tube to guide the fastener, such as a nail, into the support. The guide tube may be provided on the holder of the base part. The nail may be arranged in the guide tube with the points of the nail directed downwardly. The nail may extend upwardly from the guide tube. The projection may extend over the nail. The anchor may comprise a plurality of the guide tubes to guide a plurality of the fasteners into the support. The anchor may be movable from a non-fastened condition to a fastened condition. In the non-fastened condition, the main part may be in a raised position relative to the base part. In the fastened position, the main part may be in a lowered position relative to the base part. When the anchor is arranged on the deck, the nails may be driven into the deck by applying a downward force on the main part, for example by striking the top of the main part with a hammer to move the anchor from the non-fastened condition to the fastened condition. Thus, the nails may be driven through the guide tubes into the support to fasten the anchor to the support. The nail may comprise a shaft, which may have a pointed end. A zone of weakness may be defined by the shaft. The zone of weakness may be an annular recess. The zone of weakness may be closer to the pointed end than the opposite end. The zone of weakness may be a ring of weakness. The annular recess may be defined in the shaft at a position which is at, or below, the base part when the fastener is fully received in the guide tube. The fastener may have an end region between the zone of weakness and the pointed end. The zone of weakness may allow said end region to be broken off. The adhesive fastener may comprise a substantially planar substrate having opposite faces. The substrate may be coated with an adhesive. The adhesive may be coated on the opposite faces of the substantially planar substrate. The adhesive fastener may comprise a double-sided adhesive tape. The adhesive fastener may be annular in configuration The magnetic fastener may comprise an annular magnetic member. The magnetic fastener may be received in the recess in the underside of the base part. Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a first anchor; Figure 2 is a sectional side view of the first anchor; Figure 3 is an exploded view of the first anchor; Figure 4 is a side view of a second anchor; Figure 5 is a sectional side view of the second anchor; Figure 6 is an exploded view of the second anchor; Figure 7 is a side view of a third anchor; Figure 8 is a sectional side view of the third anchor; Figure 9 is an exploded view of the third anchor; Figure 10 shows a fourth anchor in a non-fastened condition; Figure 11 shows the fourth anchor in a fastened condition; Figure 12 is a sectional side view of the fourth anchor; Figure 13 is an exploded view of the fourth anchor; Figure 14 is a perspective side view from below of a fifth anchor; Figure 15 is a sectional side view of the fifth anchor; Figure 16 is an exploded view of the fifth anchor; Figure 17 is a perspective view of a clamp member, being a component of the anchors; Figure 18 is a front view of the clamp member; Figure 19 is a view along the lines XIX-XIX in Figure 18; and Figures 20Ato 20C show respectively one of the clamp members in engagement with three sizes of elongate article; Figure 21 is a perspective side view of a sixth anchor; Figure 22 is a side view of the sixth anchor; Figure 23 is a sectional side view of the sixth anchor; Figure 24 is an exploded view of the sixth anchor; Figure 25 is a perspective side view of a component of the sixth anchor; Figure 26 is a perspective side view of a carrier arrangement, being a component of the sixth anchor; Figure 27 is a perspective side view of the component shown in Figure 26, in which clamp members are carried thereon; Figure 28 is an upper perspective view of the sixth anchor secured to a support; Figure 29 is a lower perspective side view of the sixth anchor secured to the support; Figure 30 is a perspective side view of a seventh anchor; Figure 31 is a perspective side view of an eighth anchor; Figure 32 is a sectional side view of the eighth anchor; Figure 33 is an exploded view of the eighth anchor; Figure 34 is a top perspective view of the eighth anchor secured to a support; Figure 35 is a bottom perspective view of the eighth anchor secured to the support; Figure 36 is a lower perspective view of a carriage arrangement, being a component of the eighth anchor; Figure 37 is a side view of a further anchor; Figure 38 is an exploded view of the anchor shown in Figure 37; Figure 39 is a side view of an upper part of the anchor shown in Figure 37; Figure 40 is a top perspective view of the anchor shown in Figure 37; Figure 41 is a sectional side view of the anchor shown in Figure 37; Figure 42 is a further side view of the anchor shown in Figure 37; Figure 43 is a side perspective view of a further anchor; Figure 44 is a top perspective view of a part of the anchor shown in Figure 43; Figure 45 is a top perspective view of another part of the anchor shown in Figure 43; Figure 46 is a side view of the anchor shown in Figure 43 in one condition; Figure 47 is a side view of the anchor shown in Figure 43 in another condition; Figure 48 is a side view of a fastener; Figure 49 is a lower perspective view of a further carriage arrangement; and Figure 50 is another perspective view of the carriage arrangement shown in Figure 49. The drawings show embodiments of an anchor for use in suspending articles, such as pipes or cable trays, from a ceiling. The anchor is intended to be, at least initially, fastened to a support in the form of a deck 12 suitable for forming a ceiling. The deck 12 can be made of wood or metal. Figures 1 to 3 show an anchor 10 in the form of a ceiling anchor, which is intended to be embedded in the concrete that forms the ceiling. Such anchors 10 may be referred to as cast in place anchors, or concrete anchors. The anchor 10 comprises a main part 14 defining a passage 16 to receive an end region of an elongate article, which is in the form of a threaded rod 18 (shown in broken lines in Figures 2, 5, 7, 15). The main part 14 defines a lower first opening 20 to provide access to the passage 16 for the threaded rod 18. The first opening 20 is defined in the underside of the main part 14. Three clamp members 22 are arranged in the passage 16. The clamp members 22 are carried by a carriage 24, which is described below. The clamp members 22 define a central space 26 therebetween, and the clamp members 22 are arranged in an annular configuration around the central space 26. The threaded rod 18 extends through the central space 26 when the threaded rod 18 is received in the passage 16. The passage 16 has a converging wall region 28 having a frustoconical configuration. The wall region 28 converges towards the lower first opening 20. The clamp members 22 can move along the wall region 28 in contact therewith. Such movement in the direction of the inward convergence of the central wall region 28 causes the clamp members 22 to be urged towards each other to clamp the threaded rod 18 extending through the central space 26. Each clamp member 22 has a concave contact surface 30 (see Figures 17 to 19) to contact the threaded rod 18, and each clamp member 22 has an outer surface 32 opposite the contact surface 30. Each clamp member 22 has a plurality of spaced elongate securing ridges 34 on the contact surface 30. In the embodiment shown, each clamp member 22 has three of the spaced securing ridges 34 on the contact surface 30. The securing ridges 34 are helically oriented around the longitudinal axis of the contact surface 30. Referring to Figures 20A, 20B and 20C, The securing ridges 34 are spaced from each other by a distance that allows the securing ridges 34 to interact with threads 36 of a first threaded rod 18A, a second threaded rod 18B or a third threaded rod 18C, for the purpose securing the threaded rods 18A, 18B, or 18C to the anchor. The first, second and third threaded rods 18 are threaded rods 18 of different diameters and having respective first, second and third threads 36A, 36B, 36C. The first, second and third threads 36A, 36B and 36C are different from each other, one example of the differences being different pitches of the threads 36A, 36B and 36C. The pitch of a thread is considered to be the distance between the same point on adjacent crests of the thread. Figures 20A to 20C show schematically the interaction between the securing ridges 34 of one of the clamp members 22 and each of the first, second and third threaded rods 18A, 18B and 18C respectively. Figure 20A shows clamp member 22 interacting with the first threaded rod 18A having the first thread 36A. Figure 20B shows the second threaded rod 18 having the second thread 35B. Figure 20C shows the third threaded rod 18 having the third thread 36C. As can be seen, Figs 20A to 20C show that the securing ridges 34 of the clamp member 22 are received by the troughs of the first, second and third threads 36A, 35B and 36C. Thus, the clamp member 22 is capable of clamping any of the first, second and third threaded rods 18A, 18B, 18C. It will be appreciated that all three of the clamp members 22 interact with the first, second and third threaded rods 18A, 18B, 18C in the same way as the clamp member 22 shown in Figures 20Ato 20C. The clamp member 22 shown in Figures 20A to 20C is capable of clamping threaded rods 18 of three different sizes. It will be appreciated by the skilled person that the clamp member 22 could be configured so that it clamps threaded rods of only two different sizes. The size of the threaded rods 18 clamped by the clamp members 22 depends upon the size of the clamp members 22. A clamp member 22 of a larger size is capable of clamping larger sized threaded rods 18 than a smaller clamp member 22. Similarly, a clamp member 22 of a smaller size is capable of clamping smaller sized threaded rods 18 than a larger clamp member 22. Accordingly, in order for the anchor 10 to be able to clamp as wide a range as possible of sizes of threaded rods, different sizes of clamp member 22 may be required. It may also be necessary to have different sizes of the main part 14 with corresponding different sizes of the passage 16. The carriage 24 comprises two spaced annular retainers 40, which define opposite ends of the carriage 24 and retain the clamp members 22 between each other. The retainers 40 are substantially flat. Three equispaced elongate connectors 42 extend between the retainers 40 to connect the retainers 40 to each other. The connectors 42 are attached to a circumferential edge of each retainer 40. Each clamp member 22 is disposed on the carriage 24 between the retainers 40 The clamp members 22 are disposed on the retainers 40. The clamp members 22 may be retained on the carnage 24 between the retainers 40. In addition, each clamp member 22 is arranged between adjacent connectors 42. The anchor 10 may include an annular band 47 (see Figures 49 and 50) to hold the clamp members 22 in the aforesaid annular configuration. The band 47 is discussed in more detail below. The main part 14 comprises a housing 48 in which the carriage 24 and the clamp members 22 are housed. The main part 14 further includes a collar 50 extending around the housing 48. The collar 50 extends around the wall region 28 at the upper end of the housing 48. The housing 48 has a cylindrical configuration and the collar 50 extends circumferentially around the housing 48. The housing 48 defines the passage 16. The housing 48 further defines the first opening 20 to provide communication between a region external of the housing 48 and the passage 16. The first opening 20 is defined in an underside of the housing 48. The threaded rod 18 may extend through the first opening 20 into the passage 16. The housing 48 defines a second opening 52 opposite the first opening 20. The main part 14 further comprises a cap 54 mountable on the housing 48 in the second opening 52, so that the cap 54 extends across the passage 16, thereby closing the passage 16 at said second opening 52. The second opening 52 is defined at an upper end of the housing 48. The collar 50 extends from the housing 48 at the top of the housing 48. The anchor 10 comprises a clamping spring 56, such as a coil spring, to bias the clamp members 22 in the direction of the inward convergence of the wall region 28. The clamping spring 56 extends between the carriage 24 and the cap 54. As shown in Figures 2, 5, 7, 12, and 15, the clamping spring 56 extends between one of the retainers 40 and the cap 54. The anchor 10 comprises a base part 58 to support main part 14. The base part 58 comprises a holder in the form of a cup portion 60 to receive the housing 48. The base part 58 comprises a flange portion 62 on which the cup portion 60 is provided. The flange portion 62 extends radially outwardly from the cup portion 60. The flange portion 62 is substantially flat. The cup portion comprises an annular wall 64 on the flange portion 62. The base part 58 defines a third opening 63 aligned with the first opening 20. The third opening 63 is defined by the flange portion 62 within the cup portion 60. Thus, when the threaded rod 18 is inserted into the passage 16, the threaded rod 18 extends through the first and third openings 20, 63. A tubular member 66 can be attached to the main part 14, and can extend from the main part 14 at the first opening 20. In the relevant embodiments shown, the tubular member 66 is attached to the housing 48. Where the deck 12 is made from a metallic material, an aperture 320 (see Figure 42) may be formed therein, for example by the use of a drill. The tubular member 66 can be inserted through the aperture when the anchor 10 is arranged on the deck 12. Alternatively, the tubular member 66 can be provided on the base part 58. In the embodiments shown, the tubular member is integral with the base part 58. The tubular member 66 is in the form of a fire tube, intended to be used on a deck 12 formed of metal. The underside of such a deck 12 may be sprayed with a thick fire insulating spray to make the ceiling fire resistant. The tubular member 66 has a length that is longer than a typical thickness of the insulation applied to the deck 12. If any insulation spray enters the passage 16, it could be detrimental to the performance of the clamp members 22. Therefore, the tubular member 66 performs the function of protecting the internal mechanism of the anchor 10 from the insulation spray. The tubular members 66 may be removeable to meet the requirements for seismic bracing. In the embodiments shown in Figures 1 to 3, the tubular member 66 and the housing 48 comprise respective attachments to attach the tubular member 66 to the housing 48. In the embodiments shown in Figures 4 to 9, the tubular member 66 is integrally attached to the base part 58. Referring to Figures 2 and 3, the attachments comprise interlocking projections 68, 70 on the tubular member 66 and the housing 48. The attachments 68, 70 comprise inwardly extending projections 68 on the tubular member 66 and outwardly extending projections 70 on the housing 48. An upper end region of the tubular member 66 receives a lower end region of the housing 48. When so received, the tubular member 66 and the main part 14 can be twisted relative to each other so that the inwardly extending projections 68 extend over the outwardly extending projections 70. This movement interlocks the outwardly extending projections 70 with the inwardly extending projections 68 in order to attach the tubular member 66 to the main part 14. The anchor 10 comprises one or more fasteners to fasten the base part 58 to the deck 12, as discussed below. The fasteners may be mechanical fasteners, such as screws or nails, magnetic fasteners or adhesive fasteners. The anchor 10 shown in Figures 1 to 3, is secured to the deck 12 by means of outwardly splayed fingers 84 at the top of the tubular member 66. The anchor 10 includes an external coil securing spring 86 that functions to enable the fingers 84 to engage the underside of the deck 12, thereby securing the anchor 10 to the deck 12. The fingers 84 are formed of a resilient material. The spring also helps to keep the anchor 10 upright and vertical in the event the anchor 10 is kicked or knocked after being installed. In use, the anchor 10 is disposed on the deck 12 over an aperture 320 formed therethrough. The tubular member 66 extends through the aperture 320. As the tubular member 66 is inserted through the aperture 320, the fingers 84 are engaged by the edge of the aperture 320. A downward force can then be applied to the top of the main part 14 and to the cap, for example by striking them with a hammer or stamping on them, to drive the main part 14 downwardly relative to the base part 58. As a result, the tubular member 66 and the fingers 84 are driven through the aperture 320 in the deck 12. As the edge of the aperture 320 engages the fingers 84, the fingers 84 are pressed inwardly to allow them to squeeze through the aperture 320. When the fingers 84 have passed fully through the aperture 320 in the deck 12, the fingers 84 spring outwardly as a result of their resilience. The securing spring 86 urges the main part 14 upwardly so that the fingers 84 engage the underside of the deck 12. The securing spring 86 is under constant compression between the collar 50 and the base part 58. Thus, the force of the securing spring 86 urges the fingers 84 against the underside of the deck 12, thereby securing the anchor 10 to the deck 12. In the embodiment shown in Figures 1 to 3, the flange portion 62 is substantially rectangular. The substantially rectangular flange portion 62 defines holes 72 Fasteners, for example nails or screws, can be driven through the holes 72 into the deck 12 to fasten the anchor 10 to the deck 12. The holes 72 are shown in the corner regions of the flange portion 62, but they can be in any suitable region of the flange portion 62. The use of screws enables the anchor 10 shown in Figures 1 to 9 to be used either on a wooden deck 12 or a metallic deck 12. In the embodiments shown in Figures 4 to 9 and 14 to 16, the flange portion 62 is substantially circular, extending radially outwardly from the cup portion 60. Referring to Figures 4 to 6, the fastener is a magnetic fastener 74. The anchor 10 shown in these Figures is, therefore, only suitable for use with a deck 12 formed of an appropriate metallic material. The underside of the base part 58 defines an annular recess 76. The magnetic fastener 74, which is itself annular, is received in the annular recess 76. The base part 58 may be formed of a suitable metallic material so that the magnetic fastener 74 is mounted magnetically in the recess. In the embodiments shown in Figures 7 to 9 and 14 to 16, the fastener may comprise an adhesive fastener 78 adhered to the underside of the circular flange portion 62. The adhesive fastener 78 comprises a substantially planar annular substrate having opposite faces on which adhesive is coated. The adhesive fastener 78 is a double-sided adhesive tape. The embodiment shown in Figures 7 to 9 has a tubular member 66 and is suitable for use with a metallic deck 12 in which apertures 320 are formed therein. The embodiment shown in Figures 14 to 16 is suitable for use on wooden decks 12. In the embodiment shown in Figures 10 to 13, which is suitable for use on wooden deck 12, the anchor 10 comprises vertically extending guide tubes 80 on the cup portion 60 of the base part 58. The fastener comprises nails 82 that extend through the guide tubes 80. The nails 82 are arranged in the guide tubes 80 with the points of the nails 82 directed downwardly. The nails 82 extend upwardly from the guide tubes 80 to the collar 50. The collar 50 on the housing 48 extends over the upper ends of the nails 82. The anchor 10 shown in Figures 10 to 13 can be moved from a non-fastened condition shown in Figure 10 to a fastened condition shown in Figure 11. In the nonfastened condition, the main part 14 is in a raised position relative to the base part 58. In the fastened position, the main part 14 is in a lowered position relative to the base part 58. When the anchor 10 has been arranged on the deck 12 in the non-fastened condition, the nails 82 can be driven into the deck 12 by applying a force to the top of the housing 48 as shown by the arrow A in Figure 10, for example by striking the top of the housing 48 with a hammer. This drives housing 48 into the cup portion 60 to move the anchor 10 to the fastened condition. During this movement, the collar 50 engages the upper ends of the nails 82, thereby driving the nails 82 through the guide tubes 80 into the deck 12. This fastens the anchor 10 to the deck 12. In use of all the embodiments described above, when the anchor 10 is fastened to the deck 12, concrete can be poured over the deck 12 to form the ceiling. This embeds the anchor in the concrete. When the concrete has cured, the deck can be removed if it is a wooden deck. A threaded rod 18 can then be inserted upwardly into the passage 16. This insertion pushes the clamp members 22 upwardly along the passage 16, in the direction in which the wall region 28 diverges. This causes the clamp members 22 to move apart to allow the upper end of threaded rod 18 to be pushed through the central space 26 and through the annular upper retainer 40 to engage the cap 54. In this position of the threaded rod 18, it is received in the central space 26 between the clamp members 22. The threaded rod 18 can then be pulled downwardly. This movement, and the action of the clamping spring 56, causes the carriage 24 also to move downwardly with the threaded rod 18. The convergence of the wall region 28 urges the clamp members 22 towards each other to clamp the threaded rod 18. In the case of a deck 12 formed of metal, the anchor 10 is arranged on the deck 12 at one of the apertures 320 formed therein. When so arranged, the tubular member 66 extends through the aperture 320. Concrete can then be poured over the deck 12 thereby embedding the anchor 10 therein. When the concrete has cured, the deck 12 is not removed. A threaded rod 18 is then inserted through the tubular member 66 into the passage 16 to be clamped by the clamp members 22 in the manner described above, thereby securing the threaded rod 18 to the anchor 10. There is thus described various embodiments of an anchor suitable for use in a concrete ceiling that allows a threaded rod to be easily and quickly secured thereto. Afurther embodiment is shown in Figures 21 to 30. This embodiments comprises many of the features of the embodiments shown in Figures 1 to 20C. These features are designated in Figures 21 to 30 with the same reference numerals as the corresponding features in Figures 1 to 20C. The anchor shown in Figures 21 to 30 is generally designated 110 and comprises a holder 90 in which the main part 14 is received. As shown in Figures 24 and 25, the holder 90 comprises a central portion in the form of a cage 91. The holder 90 further includes a substantially circular top end portion 92 at the top of the cage 91, and a substantially circular bottom end portion 94 at the bottom of the cage 91. The top end portion 92 protrudes radially outwardly to allow a cap to be secured thereto and to provide support for the main part 14, as discussed below. The bottom end portion 94 protrudes through the base part 58. The cage 91 comprises three struts 100 which extend between the top and bottom end portions 92, 94. It will be appreciated that the cage 91 may comprise any suitable number of struts 100. The struts 100 are circumferentially spaced from one another around the top and bottom end portions 92, 94. When the main part 14 is received by the holder 90, the collar 50 of the main part 14 engages the radially outwardly protruding top end portion 92 of the holder 90. As a result, the top end portion 92 supports the collar 50, and also supports the main part 14 by engagement of the top end portion 92 with the collar 50. The holder 90 has a top opening 96 defined by the top end portion 92. The main part 14 is received into the holder 90 via the top opening 96. The holder 90 also has a bottom opening 98 defined by the bottom end portion 94. The bottom opening 98 is aligned with the first opening 20 defined by the housing 48 to allow the threaded rod 18 to be received in the housing 48. The fingers 84 are provided at the bottom end portion 94 of the holder 90. The threaded rod 18 is shown as broken lines in Figure 23. The tubular member 66 is attached to the holder 90 at said bottom end portion 94. In the embodiment shown, the tubular member 66 is integrally attached to the holder 90. The tubular member 66 is aligned with the bottom opening 98 and, thereby, the first opening 20. As a result, communication is provided between the inside of the main part 14 and the tubular member 66. The threaded rod 18 can be received into the passage 16 defined by the housing 48. This is done by inserting the threaded rod 18 upwardly through the tubular member 66 into the housing 48. When so received, the threaded rod 18 can be pushed through the central space 26 between the clamp members 22. Thus, the threaded rod 18 can be clamped by the clamp members 22 carried by the carriage 24. The anchor 110 shown in Figures 21 to 30 comprises a carriage arrangement 160. The carriage arrangement 160 comprises the carriage 24, the clamping spring 56, and a cap 154. The clamping spring 56 is attached to the carriage 24. As shown, the clamping spring 56 extends from one of the retainers 40 of the carriage 24. The clamping spring 56 is integrally attached to the carriage 24. The cap 154 is attached to the clamping spring 56 at the opposite end of the clamping spring 56 to the carriage 24. The cap 154 is integrally attached to the clamping spring 56. The carriage arrangement 160 is formed of a plastics material. The cap 154 extends over the housing 48, and secures the main part 14 to the holder 90. The cap 154 extends across the top opening 96 of the holder 90 and across the second opening 52 of the housing 48. The cap 154 also extends across the collar 50 of the main part 14 and across top end portion 92 of the holder 90. The cap 154 differs from the cap 54 in that the cap 154 includes a cover portion 155 and axially extending hooks 157 that extend from the periphery of the cover portion 155. The hooks 157 secure the cap 154 in place. The hooks 157 engage the lower surface of the radially outwardly extending top end portion 92 of the holder 90 when the collar 50 of the main part 14 is disposed on the top end portion 92. When the hooks 157 engage the top end portion 92, the collar 50 of the main part 14 is sandwiched between the cap 154 and the top end portion 92 of the holder 90, thereby securing the main part 14 to the holder 90. The cap 154 is attached to the clamping spring 56. The clamping spring 56 is attached to the carriage 24, so that the clamping spring 56 extends between the cap 154 and the carriage 24. The cap 154, the clamping spring 56 and the carriage 24 are integrally attached to each other. Referring to Figure 23, the cover portion 155 has central depression 156 that is received in the second opening 52. The central depression 156 has a lower face 155A. defining a recess 159. The threaded rod 18 has an upper end 18Athat is received in the recess 159 in abutment with the lower face 155A. In the embodiments described herein, the engagement of the upper end with the lower face 155A of the cover portion 155 in the recess 159 provides the advantage that lateral (side-to-side) movement of the threaded rod 18 is reduced, thereby giving confidence to users that the anchor 110 is robust. A further advantage is that there is an improvement in the performance of the anchor 110 when the threaded rod 18 undergoes shear testing, In use, after the anchor 110 is installed, the threaded rod 18 can be inserted into the passage 16 until the upper end 18A abuts against the lower face 155A of the cover portion 155 in the recess 159. In this position, the clamp members 22 engage the threaded rod 18, with the ridges 24 interacting with the thread of the threaded rod 18. The threaded rod 18 is then pulled downward, so that the convergence of the wall region 28 urges the clamp members 22 towards each other to clamp the threaded rod 18. When the user decides that the threaded rod 18 is sufficiently tightly clamped, the user can then screw the threaded rod 18 back into the main part 14 until the upper end 18A abuts the lower face 155A in the recess 159. In the embodiment shown in Figures 21 to 24, 28 and 29, the securing spring 86 extends between the base part 58 and the radially outwardly protruding top end portion 92 of the holder 90. Thus, the top end portion 92 provides a reaction force on the securing spring 86 to allow the securing spring 86 to bias the base part 58 and the top end portion 92 away from each other. Therefore, allowing the deck 12 is gripped between the base part 58 and the fingers 84. The base part 58 of the anchor 110 shown in Figures 21 to 30 includes a radially outwardly extending substantially flat plate portion 162. The third opening 63 is defined by the plate portion 162. As shown in Figures 21 to 30, the plate portion 162 is substantially rectangular. Referring to Figures 28 and 29, the anchor 110 is shown mounted on a deck 12. Figure 28 shows the anchor 110 and the deck 12 from above. Figure 29 shows the anchor 110 and the deck 12 from below. Figure 28 shows the base part 58 engaging the upper surface of the deck 12. Figure 29 shows the fingers 84 engaging the lower surface of the deck 12. Thus, the deck 12 is gripped between the base part 58 and the fingers 94, thereby securing the anchor 10 to the deck 12. Figure 30 shows a version of the anchor 110, which comprises many of the same features as the anchor 110 shown in Figures 21 to 29. These features have been designated with the same reference numerals as the corresponding features in Figures 21 to 29. In the anchor 110 shown in Figure 30, the holder 90 comprises a plurality of projecting reaction members in the form of projecting teeth102. A securing spring 186 engages the projecting teeth 102. Thus, the securing spring 186 is held between the projecting teeth 102 and the base part 58. The projecting teeth 102 provide a reaction force on the securing spring 186 so that the securing spring 186 biases the base part 58 and the top end portion 92 away from each other. The securing spring 186 in the anchor 110 shown in Figure 30 differs from the securing spring 86 in the anchor 10 shown in Figures 1 to 29 in that the securing spring 186 is shorter than the securing spring 86. Each projecting tooth 102 is provided on a respective one of the struts 100 in a region intermediate the top and bottom end portions 92, 94. As shown in Figure 30, each projecting tooth 102 is provided on a central region of a respective one of the struts 100. A plurality of strengthening fins 104 are provided to strengthen the projecting teeth 102. A respective strengthening fin 104 is provided for each projecting tooth 102. The strengthening fins 104 extend upwardly from the projecting teeth 102 along the struts 100. The securing spring 186 shown in Figure 30 extends between the base part and the projecting teeth 102. The feature of the projecting teeth 102 engaging the securing spring 86, as shown in Figure 30 provides the advantage of reducing the length of the securing spring 86, thereby reducing weight and cost. However, the securing spring 186 shown in Figure 30 still applies sufficient force to urge the fingers 84 against the underside of the deck 12, thereby securing the anchor 10 to the deck 12. The anchor 110 shown in Figure 30 is secured to the deck 12 in the same way as the anchor 110 shown in Figures 21 to 29. Further embodiments are shown in Figures 31 to XXX. The embodiments shown in Figures 31 to XXX comprises many of the features shown in Figures 1 to 30. These features are designated in Figures 31 to XXX with the same reference numerals as the corresponding features in Figures 1 to 30. In the embodiments shown in Figures 31 to 36, the anchor is generally designated 210 and comprises a holder 290, which may be formed of a plastics material. The holder 290 differs from the holder 90 in that the holder 290 comprises a central portion in the form of a casing 291. The casing 291 is in the form of a cup portion and receives the housing 48 of the main part 14. The casing 291 has a frustoconical shape that corresponds in shape and size with the external shape and size of the housing 48. The casing 291 comprises a wall 292 which extends from the top end portion 92 of the holder 290 to the bottom end portion 94 thereof. The wall 292 is devoid of apertures and is nonporous. The wall 292 is thus configured to prevent water passing therethrough. In the anchor 210 shown in Figures 31 to 36, the carriage arrangement 160 comprises a cap 254, the clamping spring 56 and the carriage 24. The cap 254 shown in Figures 31 to 36 includes the cover portion 155, but differs from the cap 154 shown in Figures 21 to 30 in that the hooks 157 are omitted. The cover portion 155 has a rim 293 defining an edge region 294. The top end portion 92 of the holder 290 protrudes radially outwardly from the casing 291 at the top opening 96 of the holder 290. An annular lip 296 extends upwardly from the top end portion 92 of the holder 290. The annular lip 296 of the holder 290 is attached to the edge region 294 of the cover portion 155, thereby attaching the cap 254 to the holder 290. The annular lip 296 may be attached to the edge region 294 as aforesaid by any suitable means known in the art, for example by a welding technique, such as ultrasonic welding. As shown in Figure 36, the cover portion 155 has a lower face 298 on which a plurality of ridges 300 are provided at the edge region 294. The ridges 300 are arranged in succession around the edge region 294 parallel to the rim 293 of the cover portion 155. The ridges 300 facilitate the attachment of the edge region 294 to the lip 296 by ultrasonic welding. The attachment of the annular lip 296 to the edge region 294 of the cover portion 155 creates a watertight seal, thereby preventing concrete from entering the passage 16, and helping to prevent corrosion caused by moisture entering the holder 290. The holder 290 and the carriage arrangement 160 are formed of a plastics material that allows them to be attached to each other by ultrasonic welding. The tubular member 66 includes an elongate part 302 and a sleeve 304 extending around an upper region of the elongate part 302. The sleeve 304 is spaced radially outwardly from the elongate part 302. Connectors in the form of ribs 306 connect the sleeve 304 to the elongate part 30. The holder 290 and the tubular member 66 comprise corresponding fasteners 308, 309 to fasten the tubular member to the holder. The fasteners 308, 309 comprise interlocking formations that interact with each other to fasten the tubular member 66 to the holder 290. In the embodiment shown in Figures 31 to 36, the fasteners 308, 309 comprise snap fit fasteners, but it will be appreciated that any other suitable fastener could be used, for example bayonet fittings or threads. The fasteners 308 of the tubular member 66 extend radially inwardly, and are provided on the sleeve 304. The fasteners 309 of the holder 290 extend radially outwardly to interact with the inwardly extending fasteners 308. The fasteners 309 are provided at the bottom end portion 94 of the holder 290 Figure 34 is a perspective view from above of the anchor 10 installed on the deck 12. Figure 35 is a perspective view from below of the same anchor 10 installed on the deck 12. Figure 34 shows the anchor 10 with the base part 58 in engagement with the upper surface 312 of the deck 12. Figure 35 shows the anchor 10 in which the fingers 84 of the tubular member 66 are in engagement with the lower surface 314 of the deck 12. The securing spring 86 urges the base part 58 downwardly onto the support, and the tubular member 66 upwardly, thereby pressing the fingers 84 against the lower surface of the support. Thus, the anchor is secured in place by gripping the support between the base part 58 and the fingers 84. Figures 37 to 42 show a further anchor, generally designated 310. The anchor 310 is similar to the anchor 110 shown in Figure 30, in that it comprises a securing spring 186, which is the same as the securing spring 186 shown in Figure 30 held between a centrally disposed annular projecting reaction member 316 and the base part 58. The anchor 310 comprises many of the features of the anchors 110, 210 shown in Figures 21 to 36. These features are designated in Figures 37 to 42 with the same reference numerals as the corresponding features in Figures 21 to 36. The anchor 310 has a holder 290 that is the same as the holder 290 of the anchor 210 shown in Figures 31 to 36. In view of this, the holder 290 of the anchor 310 comprises a central portion in the form of a casing 291. The annular reaction member 316 extends circumferentially around a central region of the casing 291. A plurality of circumferentially spaced strengthening fins 318 extend from the annular reaction member 316 along the casing 291 to strengthen the annular reaction member 316. The spring 186 of the anchor 310 is of the same relative size as the spring 186 shown in Figure 30. For the same size anchor, the spring 186 shown in Figures 37 to 41 is approximately half the length of the spring 86 shown in Figures 21 to 29 and 31 to. The provision of a shorter securing spring 186, shown in Figures 37 to 41 provides a benefit in that it limits the distance that the lower region of the anchor 310 can travel through the aperture 320 in the metal deck 12. This restricts the amount that the base part 58 can deflect and deform. Having a flat, undeformed base part 58 is important because it stabilises the anchor 310, helping the anchor 310 sit flat and present vertically. In the anchor 310, the holder 290 includes a bottom end portion 194 which protrudes through the base part 58. The anchor 310 has a tubular member 166 that is similar to the tubular member 66, but is a push fit on the bottom end portion 194. The bottom end portion 194 comprises a plurality of the outwardly splayed fingers 184 which perform the same function as the fingers 84 described above. The bottom end portion 194 is attached to the casing 291 at regions of weakness 195 adjacent the fingers 186. The regions of weakness 195 are regions of the bottom end portion 194 that are narrower than other regions of the bottom end portion 194 and allow the bottom end portion 194 to be detached from the casing 291. Detachment of the bottom end portion 194 from the casing 291 can be accomplished by striking the bottom end portion 194 from the side, for example with a hammer. This provides the advantage that the anchor 310 does not project below the underside of the deck 12, as shown in Figure 42. Figure 42 depicts the deck 12 in broken lines and shows that no part of the anchor 310 projects below the deck 12. Figure 42 also shows the aperture 320, through which no part of the anchor 310 extends. As a result of the fact that no excess material projects through the deck 12, seismic bracing plates and washers can then be installed and secured right up against the underside of deck 12. Figures 43 to 48 show an anchor 410 that is similar to the anchor 10 shown in Figures 1 to 20C. The anchor 410 comprises many of the features of the anchors 10 shown in Figures 1 to 20C. These features are designated in Figures 1 to 20C with the same reference numerals as the corresponding features in Figures 1 to 20C. The anchor 410 includes a base part 58, which comprises a cup portion 460. The cup portion 460 includes three elongate sockets 412, the purpose of which is described below. Each socket 412 defines an elongate recess 414 which communicates via an elongate slot 414 into the interior of the cup portion 460. The sockets 412 are arranged between adjacent guide tubes 80, and the sockets 412 extend parallel to the guide tubes 80. Each elongate socket 412 defines an upper opening 418. The main part 14 of the anchor 410 further includes a housing 448 in which the carriage 24 and the clamp members 22 are housed. The anchor 410 may include the carriage arrangement 160, in which case, the carriage arrangement 160 and the clamp members 22 are received in the housing 448. The housing 448 is received by the cup portion 460. The anchor 410 further includes elongate fixing ribs 416 that extend along the outer surface of the housing 448. The fixing ribs 416 are arranged on the housing 448 in positions to allow the fixing ribs 416 to be received through the upper openings 418 into the elongate recesses 414 defined in the sockets 412. The fixing ribs 416 are a friction fit within the sockets 412. Therefore, when the fixing ribs 416 are received by the sockets 412, the main part 14 is fixed to the base part 58. The fixing ribs 416 and the sockets 412 provide the advantage that they allow the anchor 410 to be assembled and retained in an assembled condition during transport and storage. In the event that the anchor were to be turned upside down or vibrated during transport the main part 14 would not separate from the base part 58. The sockets 412 and the fixing ribs 416 provide the further advantage that they allow the main part and the base part to remain attached to each other during installation. Figures 43 to 48 show the anchor 410 with a plurality of nails 182. Figure 48 shows one of the nails 182, which comprises a shaft 282 having a head 283 and a pointed end 284. A ring of weakness 288 in the form of an annular recess 286 is defined by the shaft 282 close to the pointed end 284. The nail 82 has an end region 289 between the ring of weakness 288 and the pointed end 284. The ring of weakness 288 allows the end region 289 of the nail 182 to be broken off by, for example, striking the end region 289 with a hammer, or by the use of pliers. The annular recess 286 of each nail 182 is formed in the shaft 282 at a position which will be at, or just below, the base part 58 when the nail 182 is driven into the deck 12 and fully received in the respective guide tube 80. Figure 46 shows the anchor 410 on a wooden deck 12 before the nails 82 are driven into the deck 12. Figure 47 shows the anchor 410 after concrete (not shown) has been poured over the anchor and allowed to set, and after the wooden deck 12 has been removed. As shown, with the wooden deck removed, the nails 182 project downwardly. Removal of the projecting end regions 289 of the nails 189 is desirable. The user can break off the end region 289 of each nail 182 by using a hammer to strike the end region 289, or by the use of pliers. The ring of weakness 288 may be located at such a height on the nail 82 that the end region 289 breaks off flush with the lower surface of the concrete ceiling, or just within the concrete. Referring to Figures 49 and 50, the carriage arrangement 160 of the anchor 310 is shown. The carriage arrangement 160 can also be used in the embodiment shown in Figures 43 to 48. If desired, the carriage arrangement 160 could be used in all the embodiments described herein. The carriage 160 comprises elongate connectors 42 having grooves 46. The carriage 160 also comprises clamp members 22 having grooves 44. The grooves 44 and 46 are aligned with each other in use so that an annular band 47 extends around the carriage 24 received by the grooves 44, 46, thereby retaining the clamp members 22 in the carriage 24. The grooves 44, 46 and the band 47 may be provided for the carriage arrangements 160 of each other anchor 110, 210. Figure 50 shows the carriage arrangement 160 without the band 47. This allows the grooves 44, 46 to be seen clearly. Also, if desired, the carriage arrangement 160 may be used without the band 47. Using the carriage arrangement 160 without the band 47 means that the clamp members 22 are retained in the carriage 24 by only the retainers 40. The band 47 is an elongate looped / annular flexible member, which may be formed of an elastomeric material, or may be a wire. The outer surface 32 of each clamp member 22 defines the groove 44 in which the band 47 is received. Each connector 42 has an outer edge that, in some embodiments, also defines a groove 46 to receive the band 47. The band 47 extends around the clamp members 22 and the connectors 42 to secure the clamp members 22 on the carriage 24. The band 47 is received in the grooves 44 defined by the outer surfaces 32 of the clamp members 22 and, where present, in the grooves 46 defined by the outer edges of the connectors 42. The grooves 46 defined by the connectors 42 are aligned with the grooves 44 defined by the clamp members 22. The band 47 helps retain the clamp members 22 inside the carriage 24 during assembly of the anchor 310. In addition, the band 47, arranged around the outside of the connectors 42, secures the clamp members 22 in the carriage 24 with an element of float. This allows the clamp members 22 to align themselves circumferentially around the threaded rod 5 18 so that the elongate securing ridges 34 align with the grooves in the threads of the threaded rod 18. Thus, a single design of clamp member 22 can be used. If the band 47 held the clamp members 22 in fixed positions relative to each other, three different clamp members 22 would be required, with elongate securing 10 ridges 34 at slightly different positions to grip so that the securing ridges 34 would be received in the grooves of the threads of the threaded rod 18. The binding member 47 is flexible enough to allow an appropriate element of float and to ensure the clamp members 22 remain in the carriage 24. 15 Various further modifications can be made without departing from the scope of the invention.

Claims

1. An anchor comprising: a main part defining a passage to receive an elongate article; first and second clamp members arranged in the passage to receive the article therebetween; wherein the passage has a converging wall region, and movement of the first and second clamp members along the passage in the direction of the inward convergence of the wall region urges the clamp members towards each other.

2. An anchor according to claim 1, wherein each clamp member has a contact surface to contact the elongate article, and each clamp member comprises a plurality of securing formations on the contact surface to secure the elongate article to the anchor, the securing formations being spaced from each other by a distance that allows the securing formations to be received either between corresponding formations having a first pitch on a selected first elongate article, or between corresponding formations having a second pitch on a selected second elongate article, wherein the first pitch differs from the second pitch.

3. An anchor according to claim 2, wherein each securing formation is elongate and extends across the contact surface.

4. An anchor according to claim 2 or 3, wherein the securing formations comprise a plurality of spaced elongate projections extending across the contact surface, the projections being helically oriented along the contact surface.

5. An anchor according to any preceding claim, wherein each clamp member has outer surface opposite the contact surface, and the anchor comprises a binding member extending around the clamp members.

6. An anchor according to claim 5, wherein each outer surface defines a groove for receiving an elongate binding member.

7. An anchor according to claim 6, further comprising a carriage for carrying the clamp members, the carriage having opposite retainers, wherein the clamp members are retained on the carnage by the retainers, and wherein the carriage further includeselongate connectors to connect the retainers to each other, each connector defining a groove to receive the binding member.

8. An anchor according to any preceding claim, wherein the main part comprises a housing in which the carriage and the clamp members are housed, the housing defining a first opening to provide communication between the passage and a region external of the main part, wherein the elongate article extends through the first opening into the passage, and the anchor further includes a base part to support the main part.

9. An anchor according to claim 8, wherein the housing defines a second opening opposite the first opening, the second opening may provide communication between a region external of the main part and the passage.

10. An anchor according to claim 8 or 9, wherein the base part defines a third opening, which may be aligned with the first and second openings.

11. An anchor according to claims 8, 9 or 10, wherein the base part comprises a casing to receive the main part, the casing having an internal shape and size that corresponds with the external shape and size of the housing.

12. An anchor according to any preceding claim, comprising a clamping spring to bias the clamp members in the direction of the inward convergence of the wall region, the clamping spring extending between the clamp members and the main part.

13. An anchor according to claim 12, including a carriage arrangement comprising the carriage, the clamping spring and a cap, the cap being mountable on the main part across the passage, the carnage, the clamping spring and the cap being integrally attached to each other.

14. An anchor according to any of claims 8 to 13, further including a holder to receive the main part, the holder comprising a central portion, and the anchor further including a securing spring to bias the base part and the main part away from each other, wherein the holder comprises a projecting reaction member to provide a reaction force on the securing spring, the reaction member being provided in an intermediate region of the central portion.

15. An anchor according to claim 14, wherein the securing spring extends between the base part and the reaction member.

16. An anchor according to claim 14 or 15, wherein a plurality of strengthening members are provided on the reaction member spaced around the holder, each strengthening member extending from the reaction member along the holder.

17. An anchor according to claims 14, 15 or 16, comprising a tubular member provided on the main part or on the base part, the tubular member extending from the first opening.

18. An anchor according to claim 17, wherein the holder includes a bottom end portion which protrudes through the base part, the bottom end portion being attached to the central portion at a region of weakness to allow the bottom end portion to be detached from the holder.

19. An anchor according to claim 18, wherein the regions of weakness are regions of the bottom end portion that are narrower than other regions of the bottom end portion.

20. An anchor according to any preceding claim, including a socket and a fixing rib. the fixing rib being received by the socket to fix the main part to the holder, the fixing rib being a friction fit within the socket, the socket being provided on one of the main part and the holder, and the fixing rib being provided on the other of the main part and the holder.

21. An anchor according to claim 20, wherein the socket is provided on the holder, and the socket defines an elongate recess, which communicates via an elongate slot into the interior of the holder.

22. An anchor according to claim 20 or 21, wherein the socket defines an upper opening, and the fixing rib extends along the outer surface of the main part, and the fixing rib is so arranged on the main part to allow the fixing rib to be received by thesocket, wherein the fixing rib is received through said upper opening into the elongate recess.

23. An anchor according to any preceding claim, comprising a fastener to fasten the anchor to a support, the fastener comprising a shaft having a pointed end, and the shaft defining a zone of weakness and an end region between the zone of weakness and the pointed end, the zone of weakness allowing said end region to be broken off.

24. An anchor according to claim 23, wherein anchor comprises a guide tube to guide the fastener into the support the zone of weakness being defined in the shaft at a position which is at, or below, the base part when the fastener is fully received in the guide tube.

25. An anchor arrangement comprising an anchor as claimed in claim 1, and first and second elongate articles, a selected one of which is secured to the anchor, wherein each clamp member has a contact surface to contact the elongate article, and each clamp member comprises a plurality of securing formations on the contact surface to secure the elongate article to the anchor, the securing formations being spaced from each other by a distance that allows the securing formations to be received either between corresponding formations having a first pitch on the first elongate article, or between corresponding formations having a second pitch on the selected second elongate article, wherein the first pitch differs from the second pitch.

26. An anchor arrangement according to claim 25, wherein the securing formations comprise a plurality of spaced elongate projections extending across the contact surface.

27. A connector comprising: a clamp member movable between a clamping condition and a release condition; wherein when the clamp member is in the clamping condition, an elongate article received between the clamp member and a further part of the connector is clamped by the clamp member, thereby securing the elongate member to the connector; wherein the clamp member comprises clamping formations configured to clamp elongate articles of different diameters.

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