Abstract:
A protective cap, for preventing impalement injury on rebar, comprising a tubular socket to receive an end of a length of rebar, the socket being attached to a sleeve defining a channel to receive and enclose a length of timber. Caps are also provided having a releasable gripper to grip the end of rebar.

Description:
RELATED APPLICATIONS 
       [0001]    The present application is a National Phase entry of PCT Application No. PCT/GB2014/052567, filed Aug. 21, 2014, which claims priority from GB Patent Application No. 1315032.1, filed Aug. 22, 2013 and GB Patent Application No. 1401374.2, filed Jan. 27, 2014, said applications being hereby incorporated by reference herein in their entirety. 
     
    
     OF THE INVENTION 
       [0002]    The invention relates to a device and a method for use thereof for reducing the likelihood of impalement injury, especially such injuries caused by contact with reinforcing bars of the type used in the building industry for reinforcing concrete. 
       BACKGROUND ART 
       [0003]    During the construction of buildings and other structures that use steel reinforcing bars (also referred to as rebars or rebar), there is often a period of time during construction when the end of the rebars extend out of the structure temporarily, e.g. pending construction of an abutting portion of the structure whose own reinforcing bars need to be connected to the existing rebars. The rebars are typically of approximately circular cross-section having a diameter most commonly between 10-40 mm, depending on the reinforcing requirement. 
         [0004]    The rebars are usually made of steel, and often have a coating of rust on them, from exposure to the elements. This renders them quite difficult to see. They often also have sharp edges. Building sites are also busy workplaces, with many distractions, and there is a real risk that on-site workers might, for example, trip and impale themselves on the exposed ends of the rebars, or might simply walk into the end of the rebars, causing less serious but equally unacceptable injuries. In the most extreme cases, a fall from height onto an exposed end of a rebar poses a very serious risk to life. 
         [0005]    As a result, protective devices have begun to be used that offer a level of risk reduction in respect of such injuries. One such known device comprises a circular cap, illustrated in cross-section in  FIG. 1 , and generally indicated by  1 . The cap  1  has a generally flat top  2  and a aperture  3  in the underside. It is often referred to as being “mushroom-shaped”. The cap is placed over the end of each exposed rebar where it is held in position by friction between the rebar and the interior surface of the aperture  3 . There are a number of problems with such an arrangement: A cap needs to be provided for every exposed rebar on the site, and this requires a large number of caps to be made available, and considerable time spent affixing a cap to each rebar. Also, it is relatively easy for the caps to be accidentally dislodged from the ends of the rebar, thereby reintroducing the risk to the workplace. This is especially the case where the caps are repeatedly reused and become worn, thereby reducing the friction between the caps and the ends of the rebar. 
         [0006]    An alternative design has also been introduced, sold (primarily in Canada) under the trade name “Carnie Cap”, and illustrated in cross-section  FIG. 2 , generally indicated by  4 . In this design, a tubular aperture  3  is also provided on the underside of the device, that allows the cap  4  to be slipped over then end of a rebar. On the top of the cap are provided two resiliently deformable flaps  5  that define a mouth  6 . The flaps  5  may be deformed in the direction of the arrows as illustrated, to allow a length of timber to be laid in the mouth  6 , and extend to an adjacent such cap  4 , or caps. The timber is then held in position in the caps by the use of screws, inserted through holes  7  in each of the flaps  5 . While this is an improvement on the individual caps illustrated in  FIG. 1 , the devices are quite time-consuming to fix to the exposed rebars, and require screwing to the timber length in order to protect an array of rebars. If the timber is not screwed in place, then there is a high chance that the timber might be “borrowed” for alternative use on the site. Additionally, the whole cap and timber assembly can be accidentally knocked off the end of the rebars, again re-introducing the impalement risk to the workplace. 
         [0007]    It is among the objects of the present invention to attempt a solution to this and other problems. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, embodiments of the invention provide a protective cap, for preventing impalement injury on rebar, comprising: a tubular socket to receive an end of a length of rebar; the socket being attached to a sleeve defining a channel to receive and enclose a length of timber; and wherein the axes of the socket and the channel are substantially perpendicular to each other. The provision of such a sleeve, extending onto the top surface of a length of timber makes it unnecessary to secure the timber to the cap by means of a screw fixing. In the busy environment of a building site, screws and screwdrivers might not be immediately available, with a risk that timber might not be adequately secured into caps of the prior art design. That risk is removed by the present invention. Additionally, the caps are more easily and quickly fitted to the ends of the rebar, without the need for additional tools and fixings. The sleeve preferably completely encloses (i.e. completely encircles) the timber members. 
         [0009]    Preferably, the socket is provided with a gripper to releasably grip, in use, a length of rebar inserted therein. Such a gripper could comprise a moveable clamp arrangement, or one or more longitudinal slots in the socket member which, if made of a deformable, and preferably resiliently deformable, material can be caused to grip a rebar by a clamp that encircles the socket. Preferably, however, for ease of manufacture, the gripper comprises a screw thread. This can be mounted in a threaded hole in the side of the socket, so that the thread can be screwed into the socket to urge a rebar against the opposing inner wall of the socket. A gripping portion can be mounted on the screw thread to allow it to be operated by hand. 
         [0010]    Where a gripper is used, it is preferred that the lateral cross-section of the tubular socket (perpendicular to the axis of the socket) reduces from one side of the socket to the other and the gripper is arranged to urge a rebar, in use, towards the reduced cross-section region of the socket. The cross section is preferably non-circular, and is arranged that when a rebar is urged against an inside wall of the socket, at least two points of contact between the rebar and the socket wall are made, thereby increasing the grip on the rebar. 
         [0011]    In alternative embodiments, where a gripper is provided, it is preferred that the gripper comprises one or more resiliently-deformable elongate fins located on the inside surface of the socket. In this way, when a rebar is inserted into the socket, the fins deform, resiliently, thereby gripping the outside surface of the rebar. The fins may conveniently be formed of plastics material, injection-moulded as part of the socket. 
         [0012]    In such embodiments, it is preferred that the fins extend generally longitudinally along the socket and extend inwardly, but offset from a diameter of the socket. By offsetting the fins from a diameter of the socket (i.e. so that they do not directly point at a centerline of the socket) the inventor has found that they are more easily displaced sideways, and thereby deformed, as a rebar is inserted into the socket. Preferably, the fins have a rounded edge at the end of the fin closest to the open end of the socket. This allows a rebar to be more easily inserted into the socket without damage to the fins, thereby allowing the device to be reused more often. 
         [0013]    Preferably, such an embodiment of a cap comprises two sets of fins, the first set of fins extending further into the interior of the socket that the second set, and wherein the second set extends longitudinally closer to the open end of the socket than the first set. In this way, a single protective cap may be configured to accept and grip more than one diameter of rebar. The narrower set of fins (extending closer to the open end of the socket) can grip a large diameter of rebar, and also serve to center a smaller diameter of rebar that can then be gripped by the wider set of fins. 
         [0014]    In any embodiment of a protective cap of embodiments of the invention it is preferred that a shock absorber is provided at the closed end of the socket, adjacent the sleeve. Providing a shock absorber reduces the risk that the end of a rebar within the socket could burst through the top of the cap in the event of impact to the cap, when in use. 
         [0015]    Shock absorbers such as springs or dampers could be provided, but the device is particularly cost-efficient and simple to manufacture if the shock absorber comprises a deformable projection extending from the closed end of the socket towards the open end of the socket. 
         [0016]    In any embodiment of a protective cap, it is preferred that the internal faces of the sleeve are provided with inwardly-extending ridges, the ridges being tapered such that they have smaller inward extent at an open end of the sleeve. The provision of such ridges eases the insertion of a length of material into the sleeve, while also providing grip thereon. 
         [0017]    In embodiments it is preferred that the channel is rectangular in section. This provides the ideal shape to receive a piece of timber that is likely to be readily available on a building site. An ideal timber member would be a piece of nominal 2 inch×4 inch (50 mm×100 mm) timber, and preferred dimensions for the channel are therefore approximately 100 mm wide by 50 mm tall (in use). 
         [0018]    Also in embodiments, it is preferred that the external edges of the sleeve are rounded. This reduces the chance of injury should a worker come into contact with the edges of the sleeve. 
         [0019]    Also included within the scope of the invention is a protective cap substantially as described herein with reference to and as illustrated by any appropriate combination of  FIGS. 3 to 7 . 
         [0020]    Embodiments also provide a method of shielding the ends of reinforcing bar to reduce the risk of impalement injury comprising the steps of positioning two or more protective caps on the ends of corresponding reinforcing bars and inserting a length of material through the channels of the caps. The length of material (preferably a length of wood) can be inserted through the channels either before or after the caps are positioned on the ends of the rebar. 
         [0021]    Preferably, the method further comprises the step of activating a gripper on two or more of the caps such that they grip the corresponding end of reinforcing bar. 
         [0022]    Also included within the scope of the invention is a method of shielding the ends of reinforcing bar to reduce the risk of impalement injury substantially as described herein with reference to and as illustrated by any appropriate combination of  FIGS. 3 to 7 . 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0023]    The invention will be described with reference to the accompanying drawings in which: 
           [0024]      FIGS. 1 and 2  illustrate, in cross-section, prior art devices; 
           [0025]      FIGS. 3 and 4  are elevation views of embodiments of the present invention; 
           [0026]      FIGS. 5 and 6  are cross-sectional views of sockets forming part of embodiments of the present invention; 
           [0027]      FIG. 7  is an elevation view of protective caps of embodiments of the invention in use; 
           [0028]      FIG. 8  is a perspective view of an embodiment of a protective cap of embodiments of the invention; 
           [0029]      FIGS. 9 and 10  are longitudinal and transverse cross-sections respectively of an embodiment of a socket forming part of a protective cap of embodiments of the invention; 
           [0030]      FIGS. 11 and 12  are also longitudinal and transverse cross-sections respectively of an alternative embodiment of a socket forming part of a protective cap of embodiments of the invention; 
           [0031]      FIGS. 13 and 14  are also longitudinal and transverse cross-sections respectively of an alternative embodiment of a socket forming part of a protective cap of embodiments of the invention incorporating a shock absorber; and 
           [0032]      FIG. 15  is a perspective view of a shock absorber forming part of a protective cap of embodiments of the invention. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0033]      FIG. 3  shows an elevation view of a protective cap of embodiments of the invention, generally indicated by  8 . The cap comprises a tubular socket  9  to receive the end of a length of rebar (not illustrated) within the interior  10  of the socket. The socket  10  is connected to a sleeve  11  defining a channel  12  to receive a length of timber (not illustrated). The exterior edges  13  of the sleeve  11  are rounded. Reinforcing fillets  14  are provided between the sleeve  11  and the socket  9 , to add strength to the cap  8 . 
         [0034]    In the embodiment illustrated, a hole  15  is provided through the wall of the socket  9  and communicating with its interior  10  to receive a screw thread (not illustrated) that can be used to grip a rebar, in use. The hole may be preferably threaded, but if a relatively soft material (e.g. a plastics material, such as polypropylene) is used for the cap, then threading is not necessary, and a self-tapping screw thread may be employed. 
         [0035]      FIG. 4  shows a side elevation view of a protective cap of an embodiment of the invention, generally indicated by  8 . 
         [0036]      FIG. 5  shows a partial cross-section through the socket of the device of  FIG. 4 , at the line AA′ in  FIG. 4 . The section shows an embodiment where the cross-section of the interior  10  of the socket  9  is non-circular, and decreases in a direction away from the gripper (in this case in the form of a screw thread)  16 , thereby urging, in use, the rebar  17  into two-point contact with the interior wall of the socket  9 . A gripping portion  19  is provided on the thread  16  to allow it to be tightened by hand. 
         [0037]      FIG. 6  illustrates a further, alternative cross-section of the socket  9  where the interior  10  is of triangular cross-section. It can be seen that if a gripper mechanism urges a rebar  17  in the direction indicated by arrow  18  then this also urges the rebar  17  into two-point contact with the interior wall of the socket  9 . 
         [0038]      FIG. 7  illustrates protective caps  8  of the invention in use. Three caps  8  are illustrated in elevation view, each of which are attached to an end of a projecting rebar  17 . The rebars are approximately collinear, allowing a length of material, such as timber  20  to be slotted through the channels in the sleeves  11  of the caps  8 . The timber member  20  thereby not only shields the ends of the rebar  17  to which the caps  8  are connected, but also those other rebar ends that fall beneath the timber member  20 . 
         [0039]      FIG. 8  illustrates a preferred embodiment of a protective cap of the invention, generally indicated by  8 . The cap may conveniently be made as of one-piece injection-molded plastics. The cap  8  comprises a tubular socket  9  connected at a closed end to a rectangular sleeve  11 . A T-shaped fillet  21  is provided between the socket  9  and the sleeve  11  to provide structural strength. Inwardly-facing ridges  22  are provided within the interior of the sleeve  11 . The ridges are provided with a taper, such that their inward extent is smaller at an end of the ridge  23  adjacent an open end of the sleeve. 
         [0040]      FIG. 9  illustrates a longitudinal cross-section though a tubular socket forming part of a protective cap of the invention.  FIG. 10  illustrates a corresponding transverse cross-section. In this embodiment, the interior of the socket  9  is provided with inwardly-facing fins  24 , extending longitudinally along the socket from the closed end of the socket  25  towards the open end of the socket  26 . The fins  24  have a rounded profile  27  at the end closest to the open end  26  of the socket  9 . As may be more clearly seen in  FIG. 10 , the fins  24  extend into the interior  10  of the socket, but not along a diameter of the socket (illustrated by the chain-dotted lines  28 ), i.e. they do not point directly towards the centerline of the socket. As discussed above, this makes insertion of a rebar into the socket easier, and prevents damage to the fins. 
         [0041]      FIG. 11  illustrates a longitudinal cross-section through a tubular socket forming part of a protective cap of the invention.  FIG. 12  illustrates a corresponding transverse section. In this embodiment, two sets of fins  24 A and  24 B are provided. The first set of fins  24 A (not illustrated in  FIG. 11 , but corresponding to those illustrated in  FIG. 9 ) extend further into the interior of the socket  10  than the second set of fins  24 B. i.e. there is a set of wide fins  24 A and a set of narrow fins  24 B. The second, narrower, set  24 B also extend closer to the open end  26  of the socket than the second set  24 B. In this way, if a large diameter rebar is inserted into the open end  10  of the socket  9 , the narrower set of fins  24 B can grip it and hold it in position. The rebar need not be inserted so far into the socket as to be gripped by the wide set of fins  24 A. If the cap is used with a smaller diameter rebar, the narrow set of fins  24 B act to center the rebar in the socket  9 , and the wider set of fins  24 A serve to grip the rebar. 
         [0042]      FIG. 13  illustrates a longitudinal cross-section of an embodiment of a tubular socket  9  forming part of a protective cap of the invention.  FIG. 14  illustrates a corresponding transverse cross-section. Inwardly-facing fins  24  are provided on the interior of the socket  9 . A shock absorber  29  is provided at the closed end  25  of the socket. In this embodiment, the shock absorber  29  is in the form of a deformable cross-shaped projection extending from the closed end  25  of the socket  9  towards the open end  26 . If an impact force is exerted on the top of the cap in use, the projection can deform to absorb some of the energy of impact, thereby reducing the chance that the rebar would burst through the closed end of the socket, and so improving the protective qualities of the cap. As can be seen in  FIG. 14 , by using a cross-shaped shock absorber  29 , the shock absorber can extend between the offset fins  24  of the device, allowing it to be a larger size than would otherwise be possible, thus enabling to absorb more energy in the event of impact. 
         [0043]    In the embodiment illustrated in  FIGS. 13 and 14 , one set of fins  24  is shown, but the shock absorber could readily be employed with a socket having two sets of fins such as that illustrated in  FIGS. 11 and 12 . 
         [0044]      FIG. 15  is a perspective view of a shock absorber  29  of the embodiment mounted on the closed end  25  of the socket.