Patent Publication Number: US-2012037451-A1

Title: Anchor for a height safety system and height safety system incorporating an anchor

Description:
TECHNICAL FIELD 
     The present invention relates to the field of safety devices and particularly relates to anchors which provide a mounting point for a height safety system for use in ensuring worker safety when working in or near to potential fall zones. 
     BACKGROUND TO THE INVENTION 
     When working near to a fall zone, such as near to the edge of a raised platform with no railings, there is a significant risk of injury to workers. In order to guard against this, height safety systems can be used such as a fall arrest or fall restraint systems which typically involve attaching a safety line to a worker by way of a harness. A fall restraint system operates to restrain a person from reaching a position where they can fall. A fall arrest system operates to arrest a person&#39;s fall in the event of a fall. 
     When working inside a building, a height safety system can be set-up whereby one end of the safety line is fixed to a sturdy anchor point such as a beam, pillar or other structural building element and the other is fitted to the harness of a worker. However, when working in remote or field locations, there is rarely a suitable sturdy anchor point available to attach the line to. 
     SUMMARY OF THE INVENTION 
     In a first aspect the present invention provides an anchor for use in a height safety system, the anchor including: a generally elongate member; an attachment point for a safety line is provided at one end of the member; the anchor is arranged to be affixed to a sturdy object so that, in use, the attachment point is in a raised position. 
     The elongate member may include a resilient portion which is arranged to deform in the event of a fall. 
     The resilient portion may be formed from thermoplastic. 
     The attachment point may be rotatably mounted to the elongate member. 
     The anchor may be arranged to be affixed to a towing hitch of a vehicle. 
     The anchor may be arranged to fit to an upright scaffolding member. 
     The anchor may further include a second attachment point for a safety line provided proximate to the other end of the elongate member. 
     In a second aspect the present invention provides a height safety system including an anchor according to the first aspect of the invention and further including stabilising members that extend from the anchor. 
     The stabilising members may act in tension. 
     The stabilising members may act in compression. 
     The height safety system may further include a safety line that is arranged to be strung between the attachment points of the two anchors. 
     In a third aspect the present invention provides a method of installing a height safety system including the steps of: providing an anchor according to the first aspect of the invention; and attaching the anchor to a vehicle. 
     The anchor may be attached to the tow hitch of a vehicle. 
     In a fourth aspect the present invention provides a method of installing a height safety system for performing work on an elevator including the steps of providing an anchor according to the first aspect of the invention; and attaching the anchor to the top side of an elevator. 
     In a fifth aspect the present invention provides a method of installing a height safety system for performing work assembling or disassembling a scaffold including the steps of providing an anchor according to the first aspect of the invention; and attaching the anchor to an upright portion of the scaffold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a side view of an embodiment of an anchor for use in a height safety system; 
         FIG. 2  is a front view of the anchor of  FIG. 1 ; 
         FIG. 3  illustrates the anchor of  FIG. 1  in use with a utility vehicle; 
         FIG. 4  is a side view of another embodiment of an anchor; 
         FIG. 5  is a side view of the anchor of  FIG. 4 ; 
         FIG. 6  is a side view of yet another embodiment of an anchor; 
         FIG. 7  is a side view of the anchor of  FIG. 6 ; 
         FIG. 8  is a bracket for use in securing the anchor of  FIG. 6  to a vehicle; 
         FIG. 9  illustrates an adjustable height leg for the anchor of  FIG. 6 ; 
         FIG. 9  shows the anchors of  FIGS. 4 and 6  employed in a height safety system in conjunction with a mining vehicle; 
         FIG. 11  is a front view of yet another embodiment of an anchor; 
         FIG. 12  is a side view of the anchor of  FIG. 11 ; 
         FIG. 13  is a top view of an adaptor for use with the anchor of  FIG. 11 ; 
         FIG. 14  is a front view of the adaptor of  FIG. 13 ; 
         FIG. 15  is a front view of a further embodiment of an anchor; 
         FIG. 16  is an underside view of the anchor of  FIG. 15 ; 
         FIGS. 17 to 17C  illustrate another embodiment of an anchor; 
         FIG. 18  is a top view of another embodiment of an anchor; 
         FIG. 19  is a side view of the anchor of  FIG. 18 ; and 
         FIG. 20  is a perspective view of a height safety system including another embodiment of an anchor. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2 , an anchor  10  is shown for use in a height safety system. The anchor  10  includes an elongate member  12 , which is comprised of an upper section  16  which is joined to a lower section  14  by way of a resilient portion in the form of an insert  17  which is formed from thermoplastic material and secured by fasteners. Anchor  10  further includes a horizontal portion  19  which is dimensioned to fit to a standard Hayman Reese type towing hitch as are often found on utility vehicles, four wheel drives, and light trucks. The anchor is secured to the hitch with a locking pin which fits through hole  22 . Horizontal portion is welded to upright  14  and is strengthened with a brace plate  20 . All of sections  14 ,  16  &amp;  19  are formed from square section mild steel. Sections  16  and  14  can be separated to take up less storage space for easier stowing of the anchor, such as in the boot of a vehicle. The anchor  10  includes an attachment point in the form of a rud lug  18  which is rotatably mounted to the upper end of the anchor  10  and is free to rotate and to swivel in an up and down direction. 
     Referring to  FIG. 3 , a worker wishes to perform some work near to the fall zone, indicated by arrow “A”. The worker sets up a fall restraint system using anchor  10  in the following manner. The worker parks his utility vehicle  30  near to the fall zone “A”. Sections  14  and  16  are joined together using fasteners. Anchor  10  is then affixed to the Hayman Reese type towing hitch  32  already present on the worker&#39;s vehicle. The worker puts on a harness and attaches himself with a safety line (not shown) to the rud lug  18 . The effective length of the safety line is then adjusted so that the worker cannot reach the fall zone. The anchor  10  allows the utility vehicle  30  to be used as a sturdy object for attaching the safety line. Further, because the rud lug is in a raised position, the line does not present a trip hazard to the worker whilst using the fall restraint system. 
     Referring to  FIGS. 4 and 5 , an alternative embodiment of an anchor will now be described using like reference numerals in the  100  series. This anchor is suitable for use when working on vehicles such as the Eimco type mining vehicle produced by Sandvik AB. Anchor  100  includes an elongate member  112  formed from joined sections  114  and  116  and a first attachment point in the form of rud lug  118  as in the previous embodiment. The sections  114  and  116  are formed from circular section mild steel tube. The sections are joined by way of a thermoplastic insert  117  which is a sliding fit inside sections  114  and  116  and is secured with fasteners. Near to the lower end a second attachment point  115  and a circular flange  119  are provided. The circular tube  116  is selected to be a close fit inside the standard towing hitch provided at the rear of Eimco vehicles. The flange  119  limits the depth of insertion of the anchor  10  into the Eimco towing hitch. A locking pin is inserted through hole  122 . The anchor  10  can be used with an Eimco vehicle in a similar manner as described for the utility vehicle above. 
     In some cases, a worker may wish to perform work which involves moving around on top of the Eimco vehicle itself. In this case, a height safety system can be used incorporating the anchor of  FIGS. 4 and 5 , and further incorporating the anchor  200  of  FIGS. 6 to 9  which is arranged to be installed towards the front end of an Eimco vehicle. 
     Referring to  FIGS. 6 &amp; 7 , a further alternative anchor  200  is shown which again includes an elongate member  212  and a rud lug  218 . Anchor  200  includes a threaded stub  214  which receives threaded bracket  216 . Anchor  200  further includes a leg of adjustable height formed from threaded stands  218 ,  220 . A hole  215  allows attachment of a threaded bar and clamp. 
     Referring to  FIG. 10 , a height safety system incorporating anchors  100 ,  200  is shown in use with an Eimco vehicle  40 . First, a safety line  400  formed from 8 mm diameter wire rope is attached to lug  218  of anchor  200  and the free end of the safety line is threaded through the lug  118  of anchor  100 . Anchor  100  is then fitted to the towing hitch  46  as described above. Anchor  200  is fitted towards the front of the vehicle in the following fashion. Member  212  is inserted through a lug  42  which is a standard feature on Eimco vehicles. Member  212  is then fitted over stand  220  which is threaded to allow for height adjustment. Bracket  216  is threaded to member  212 , and is then inserted into sleeve  44 , again a standard feature of Eimco vehicles. A threaded bar and clamp (not shown) is attached at through hole  215  which clamps against the top of the Eimco vehicle. 
     Once both anchors  100 ,  200  are in place, the safety line  400  is pulled tight and attached to attachment point  115 . A turnbuckle rated at 2.5 tons is situated between the attachment point  115  and the safety line  400 . The turnbuckle allows for the safety line to be tensioned prior to the worker attaching to the safety line. A worker may then attach themselves to the line  400  by way of their own safety line and harness. An inertia reel may be employed as a fall arrest device. The worker may thus perform work on top of the Eimco vehicle  40  and is prevented from falling from the vehicle. 
     To dismantle the system, safety line is released from attachment point  115  and thereafter disassembly is the reverse of the assembly steps. 
     Referring to  FIGS. 11 to 14 , a still further embodiment of an anchor  300  is shown. This anchor can be used to affix to miscellaneous sturdy objects. Again anchor  300  includes an elongate member  312  formed from upper and lower sections  316 ,  314  and has a rotatable rud lug  318  at its upper end. This anchor includes a latch mechanism including rotatable handle  317  and keeper  319 . An adaptor  320  is provided for mounting the anchor. Adaptor is fitted to a sturdy object by welding or by use of bolts with through holes  322 . The mast may then be removably secured to the adaptor  320  by way of inserting the lower end of mast into recess  323  and engaging keeper  319  with aperture  324  by inserting the keeper and rotating handle  317  through 90 degrees. The anchor may then be used to attach a height safety system. After use, the anchor is quickly removed by releasing the latch mechanism. 
     Referring to  FIGS. 15 and 16 , an anchor  400  for a height safety system is shown. Anchor  400  is intended for attachment to a tow hitch of a vehicle and is a modified version of anchor  10  shown in  FIGS. 1 to 3 . In this version, three stabilising members in the form of legs  410  extend from the anchor. Each leg is adjustable in length by way of a series of holes and a pin. Each leg is set to the desired length, and a pin is inserted through the corresponding hole. This version is installed in the same manner as the anchor  10  above. Following installation, the legs  410  are spread apart and their length adjusted to bear against the ground. The legs act in compression to stabilise the anchor. The legs  410  are prevented from spreading by way of chain links  420 . This version can be used when a fall arrest arrangement is required. The legs  420  provide a tripod arrangement and serve to avoid rolling of the vehicle to which the anchor is attached in the event of a fall or other load applied to the safety line. The elongate portion of the anchor includes an insert of thermoplastic material  417  to absorb energy of shock loads. 
     Anchors operating on similar principles to anchors  10 ,  100 , &amp;  400  may be used to attach to other types of vehicles. For instance, referring to  FIGS. 17 to 17C , an anchor arrangement is shown which is suitable for attaching to a mining vehicle known as an LHD (Load Haul Dump) vehicle. The arrangement includes an anchor  510  which is formed from lengths  512  and  514 , joined by an internal thermoplastic insert (not visible). LHD vehicles are fitted with various types of tow hitches, and a range of tow hitch attachments of various dimensions  516 ,  518 ,  520  &amp;  522  are provided. To fit the anchor to an LHD vehicle, the appropriate one of attachments  516 ,  518 ,  520  &amp;  522  is selected and fitted to the bottom end of anchor  510  and anchor  510  is fitted to the tow hitch. To stabilise the anchor  510 , a sleeve and bracket arrangement is used. Sleeve  524  slides onto anchor  510 . Bracket  526  includes a flange  528  which abuts and rests on a wall of the LHD vehicle. The legs  530  of bracket  526  slide into channels  532  of sleeve member  524 . A strap and ratchet arrangement is passed through handle  534  of sleeve member  524  and passed about a bodywork or chassis member the LHD vehicle. Locking pins are inserted through the appropriate hole in legs  530  and the strap and ratchet tightened. Anchor  510  is now ready for attachment of a safety line. 
     Referring to  FIGS. 18 and 19 , another embodiment of an anchor  600  is shown. This anchor is intended for use when assembling or disassembling scaffolding. Safety regulations typically provide that workers must use a height safety system when working above a certain height. This height limit is usually exceeded when assembling or disassembling scaffolding. It is sometimes necessary to use a cherry picker or other similar device to ensure worker safety guidelines are met as there is usually no convenient point to attach a height safety system. The anchor  600  solves this problem by providing a raised attachment point  618  for attaching a height safety system. 
     Anchor  600  includes an upper member  616  and a lower member  614 , these are joined by way of an insert of thermoplastic material  617  as for the previously described embodiments and the upper member  616  carries an attachment point in the form of rud lug  618 . Anchor  600  further includes a sleeve  620  which is attached to lower member  614  by way of web  622 . Sleeve  620 , web  622  and lower member  614  are joined by welding. 
     Scaffolding includes a number of upright members. When assembling or disassembling scaffolding, anchor  600  is fitted to the scaffolding by sliding sleeve  620  over an exposed end of an upright scaffolding member. Anchor may be secured to the upright member by inserting a locking pin through hole  624 . A height safety system may then be attached to rud lug  618  with the usual harness attachment to a worker. In the event of a worker falling, then the anchor  600  arrests their fall. As for previously described embodiments, thermoplastic insert may deform to absorb energy and reduce risk of injury to the worker. Also, deformation of the thermoplastic insert acts as a tell tale to indicate that a fall event has occurred. 
     As the scaffolding is assembled or disassembled, then the anchor  600  is removed and re-fitted higher up, or lower down on the scaffolding as required. Two of anchors  600  may be used so that one of anchors  600  is always affixed to the scaffolding to provide an attachment point for a height safety system. 
     Referring to  FIG. 20 , another embodiment of an anchor  700  is shown. This anchor is formed from an upper member  716  and a lower member  714 . The members are joined by way of a square section thermoplastic insert  717  which fits inside the ends of both of upper and lower members  716 ,  714  and is secured with fasteners. This anchor is intended for attaching to a workshop floor or other concrete surface by way of base plate  720  through which are inserted into the floor anchors such as dynabolts. Stabilising members in the form of steel cables are provided which are themselves secured to the floor by way of floor plates  722  and dynabolts. The steel cables attach to eyelets  726  which are welded to lower member  714 . In use, the steel cables  724  operate in tension. 
     Anchor  700  is intended for use either with another like anchor, or with another sturdy attachment point, such as a wall of a building, to set up an overhead static safety line will now be described. First, one end of the static line (not shown) is attached to rud lug  718  on one of anchors  700  and the free end is threaded through the rub lug  718  provided on another similar anchor  700 . The anchors  700  are then affixed to the floor in the desired location along with floor plates  722  and steel cables  724  are installed and pre-tensioned so that the masts are situated on either side of the potential fall zone. The free end of the static line is then attached to eyelet  715  and pulled tight. The static line is now strung overhead the work area. The static line is used as an attachment point for attaching fall arrest devices, such as inertia reel devices. 
     The static line may be lowered by releasing the end from eyelet  715  and allowing the line to go slack. If needed, a cord or rope or the like can be attached to the free end of the safety line which can be paid out to lower the safety line to ground level. Lowering the safety line is useful in the event that plant or other tall machinery needs to be moved across the work area that would otherwise foul on the static line. Similarly, the static line can be lowered for attaching or removing inertia reel devices or other safety lines. Workers may thus work in the work area with height safety arrangements in place. 
     Should a worker fall from a height, the inertia reel locks within about 200 mm of falling. The worker&#39;s fall is then broken by the static line. The attachment points  718  experience the shock load of arresting the fall, plus the bending moment of the weight of the fallen person. Thermoplastic inserts  717  of both masts deform under the load on the safety line to absorb the shock loads to prevent these being transferred to the line attachment points or to the worker, via their harness. The deformation of the inserts reduces shock loads and helps reduce the likelihood of injury to the worker as might be caused by a sudden stop in the harness, such as broken ribs or the like. 
     Testing has demonstrated that an embodiment the overhead static line is suitable to carry a maximum of two persons to a combined weight of 320 kg. 
     It can be seen that embodiments of the invention have at least the following advantages:
         A height safety system can be set up in remote outdoor locations by attaching to a vehicle   The height safety system can be dismantled and stored in the vehicle   A height safety system can be provided to allow for working on top of a vehicle   A height safety system can be provided which can affix to a wide range of sturdy objects   Deformable inserts absorb energy to reduce shock loads and risk of associated injuries. Thus, a worker may avoid medical treatment, and could even continue working on the same day as experiencing a fall event.       

     Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated. 
     Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention.