AU3018499A - A roof safety system - Google Patents

Description

WO99/49154 PCT/AU99/00197 1 "A ROOF SAFETY SYSTEM" THIS INVENTION relates to a safety system for workers on roofs or similar elevated locations. In particular, the invention is directed to a roof anchor 5 and/or clamp suitable for use with a rope and safety harness for rooftop workers. The disclosure of Australian patent application No. PP2468, from which this application claims priority, is incorporated herein by reference. 10 BACKGROUND ART In many areas, occupational health and safety regulations require that scaffolding be erected around the perimeter of a roof to serve as a safety barrier for 15 workers on the roof. The erection of such scaffolding is not only time consuming, but also expensive. Furthermore, for small roof jobs, such as roof spot repair or installation of a ventilator, the cost of scaffolding is considerably more than the cost of the 20 actual job. Since the cost of roof scaffolding is prohibitive in such circumstances, some roof workers may be tempted to carry out small jobs without scaffolding or other safety measures, thereby leading to an unsafe work environment. 25 There is a known "rope and harness" safety system for roofworkers. The roofworker wears a harness (e.g. a belt) which is connected to one end of a safety rope. The other end of the safety rope is connected to an anchor point at an upper portion of the roof, e.g. at the 30 roof ridge. Some buildings may have an exposed hook at or near the roof ridge to permit quick connection of the safety rope. Although the known rope and harness system is significantly cheaper than perimeter scaffolding, it 35 still has an inherent disadvantage. Namely, the worker must climb to the upper part of the roof to connect the safety line. Until the line is connected, the worker is at risk. Similarly, at the end of the job, the worker WO99/49154 PCT/AU99/00197 2 must disconnect from the roof and descend to a ladder or scaffold at the roof edge. During such descent, the worker is again at risk as the safety rope is no longer connected. 5 It is an object of this invention to provide an improved safety system for roofworkers. In particular, it is an object of this invention to provide a roof anchor and/or rafter clamp for use with a rope and harness safety system. 10 SUMMARY OF THE INVENTION The invention relates to a roof safety system having roof fixing means adapted to be fixed adjacent to one edge of a roof, a harness adapted to be worn by a 15 roofworker, and a safety line connected between the roof fixing means and the harness, the safety line being of sufficient length to extend to the opposite edge of the roof, yet short enough to arrest the fall of a roofworker from the opposite edge. 20 In one embodiment, the roof fixing means comprises a roof anchor adapted to hook onto the bottom edge of the roof cladding, which may be sheet metal or tiles for example. The roof anchor is typically of hook like configuration. The hook portion is variable in size 25 to suit cladding of different thickness. In a preferred version of this embodiment, the roof anchor is of T-shaped configuration, having a shank and a crosspiece. The crosspiece has at least one finger portion which engages under the bottom edge of the roof 30 cladding. The shank may be of arched section to suits its application to a corrugated iron roof. A hook or loop is provided on the shank, for easy connection to one end of the safety line. 35 In another embodiment, the roof fixing means is a clamping mechanism adapted to clamp onto a rafter, truss top chord or like roof frame member. The rafter clamp is suitable for use on uncovered roofs.

WO99/49154 PCT/AU99/00197 3 In a preferred version of this embodiment, the clamping mechanism has at least one toothed cam pawl which is biased against the frame member. The pawl resists movement of the clamping mechanism relative to 5 the frame member under load. Both the roof anchor and the clamping mechanism may have additional clamping means to fix the anchor or clamping mechanism in position. In order that the invention may be more fully 10 understood and put into practice, embodiments thereof will now be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS 15 Fig. 1 is a schematic elevation showing the rope and harness safety system of this invention, in use; Fig. 2 is an exploded perspective view of a roof anchor for use in the rope and harness system; Fig. 3 is an exploded perspective view of the 20 roof anchor of Fig. 2 being fitted to a metal roof; Fig. 4 is a sectional elevation of the roof anchor fitted to a metal roof; Fig. 5 is an underside perspective of the roof anchor fitted to a metal roof; 25 Fig. 6 is a sectional elevation of the roof anchor fitted to a tiled roof; Fig. 7 is an underside perspective of the roof anchor fitted to a tiled roof; Fig. 8 is a perspective of a roof clamp 30 suitable for use with a rope and harness system; Fig. 9 is a front elevation of the roof clamp of Fig. 8; Fig. 10 is a perspective view of the roof clamp of Fig. 8 fitted to a rafter. 35 DESCRIPTION OF PREFERRED EMBODIMENTS In the rope and harness safety system illustrated schematically in Fig. 1, a person 1 working WO99/49154 PCT/AU99/00197 4 on a roof 2 at one side of a building wears a harness 3 which is connected by safety rope 4 to roof fixing means 10 on the other side of the building, i.e. on the opposite side of the roof ridge. The safety rope 4 is of 5 such length that it permits the worker 1 to move over the roof 2, yet will arrest the fall of the roof worker in the event that the worker slips or falls off the roof. The safety rope may be of adjustable length, or adjustably connected to the safety harness 3 and/or the 10 roof fixing means, so that the worker can set the effective length of the safety rope for the particular roof on which it is used. In one embodiment of this invention, the roof fixing means is a roof anchor 11 as shown in Figs. 2-7. 15 The illustrated roof anchor is suitable for roofs of corrugated iron or sheet metal, tiled roofs, and other clad roofs. As shown in Figs. 2-4, the roof anchor 11 is generally T-shaped, and comprises a shank portion 12 20 connected at its front end to an angle-section crosspiece 13. The crosspiece 13 has a pair of vertically spaced slots 14A, 14B, as well as a threaded stud 15 extending forwardly of the crosspiece 13. An angle section 16 is provided for use with 25 the anchor 11. The angle section 16 has an aperture 17 in one arm thereof ("the apertured arm"), which is dimensioned to receive the threaded stud 15. A wing nut 18 is also provided for threading onto the stud 15. The angle piece 16 may be mounted onto the threaded stud 15 30 in either of two orientations as shown in Fig. 2. Depending on the orientation, the other arm of angle piece 16 ("the finger arm") locates in one or other of the slots 14A, 14B, and forms a finger extending rearwardly under the crosspiece 13. In side elevation, 35 the shank 12, crosspiece 13 and finger arm form a generally C-shaped anchor hook which, in use, can be hooked over the bottom edge of a roofing sheet or tile as described below. However, any other hook-like WO99/49154 PCT/AU99/00197 5 configuration may be used. A boss 19 is provided on the crosspiece 13, the boss 19 having a threaded throughhole. A clamping bolt 20 is provided with the roof anchor 11, for threading into 5 the throughhole in boss 19. The bolt 20 may suitably have an angled handle to enable it to be manually threaded into the boss 19. A hook or loop 21 is provided at the rear end of the shank 12, i.e. the end opposite the crosspiece, 10 for connection to the safety rope 4. The shank 12 is increasingly arched in transverse section along its length, and has a slot 22 extending longitudinally along the top of the arched shank. A curved washer plate 23 of matching curvature may 15 be provided with the shank 12, and has an aperture 24 which, in use, is aligned with the slot 22 thereunder. Typically, the roof anchor 11 is made from mild steel, but any other suitable material will suffice. In one application, the roof anchor 11 is 20 hooked to the bottom edge of a sheet of roofing iron 25, usually the lowest sheet, as depicted in Figs. 3-5. The roof anchor 11 is placed on the roofing sheet 25 so that the angled crosspiece 13 overhangs the bottom edge of the sheet. The angle section 16 is placed on the threaded 25 stem 15 in the orientation shown in Fig. 3, so that the finger arm passes through slot 14A and under the bottom edge of the roof sheet 25 (as depicted in Fig. 4). Wing nut 18 is used to secure the angle section 16 to the threaded stem 15. The crosspiece 13 and finger arm 30 effectively form a hook configuration around the bottom edge of the roof sheet 25. The clamping bolt 20 is then screwed manually into boss 19 to clamp the roofing sheet 25 between the bolt and the finger arm of angle section 16. This 35 clamping action secures the roof anchor to the roof and prevents it from sliding off the roof when there is no load on it. Other suitable clamping mechanisms can be used instead of the clamping bolt.

WO99/49154 PCT/AU99/00197 6 Further, or in the alternative, if the roof anchor 11 is being used on a screwed-down corrugated iron roof, a screw fastener is first removed from a bottom sheet of corrugated iron and the washer plate 23 is 5 placed on the shank 12 so that the aperture 24 in the washer plate 23 is aligned with both the slot 22 and the hole in the roof sheet from which the screw fastener was removed. The screw fastener can then be inserted in the aligned aperture 24 and slot 22 and screwed back into its 10 original hole to thereby fasten the roof anchor 11 to the roof. The roof anchor 11 can be fixed in position by an operator standing on a ladder at the bottom edge of the roof. That is, the operator need not climb onto the 15 roof in order to fix the roof anchor. Once the roof anchor 11 is fixed in position, the safety rope 4 is attached to loop 21, and the other end of the rope is thrown over the roof ridge as shown in Fig. 1. The operator moves to the opposite side of the 20 building, and can reach the other end of the rope by climbing the ladder. The other end of the rope is then attached to a safety harness worn by the operator while the operator is still on the ladder. That is, the operator need not climb onto the roof before connecting 25 to the safety system. While on the opposite side of the roof, the operator is prevented from falling to the ground by the safety rope 4 connected to the roof anchor hooked to the bottom edge of the roof sheet 25. 30 Upon completion of the roof tasks, the operator is able to return to the ladder before disconnecting the safety rope from his harness. The roof anchor can be retrieved from the other side of the building by removing bolt 20, and sliding the anchor out from the edge of the 35 roof sheet 25. (The washer plate 23 would also need to be removed if used). The above procedure is repeated on the other side of the building, if work is to be done on the WO99/49154 PCT/AU99/00197 7 opposite roof. Figs. 6 and 7 illustrate another application of the roof anchor 11, namely on tiled roofs. As tile cladding is thicker than sheet metal cladding, the angle 5 piece 16 is inverted before fitting to the threaded stud 15, to thereby create a larger clearance between the finger arm of the angle section 16 and the crosspiece 13, as shown in Fig. 6. The combination of the crosspiece 13 of the anchor 12 and the finger arm 16 forms a generally 10 C-shaped arrangement which is hooked onto the lower end of a tile 26, usually in the bottommost course of roof tiles. Again, the bolt 20 is manually threaded into boss 19 to clamp the roof tile 26 between the finger arm 15 16 and the bolt, thereby ensuring that the roof anchor 11 does not slip off the roof. It will be apparent to those skilled in the art that the abovedescribed roof anchor and roof safety system have several advantages, including 20 (i) The roof anchor can be constructed easily and economically. (ii) The roof anchor is compact, and can be carried 25 in the worker's vehicle for ready access. (iii) The roof anchor is quickly and easily installed on a roof, without special tools. 30 (iv) The use of perimeter scaffolding is avoided. (v) The roof anchor allows a roof worker to be connected to the roof safety system prior to climbing onto a roof, and to remain connected after climbing back 35 onto the ladder, so that the worker remains connected to the safety system at all times while on the roof. (vi) The roof anchor is suitable for both metal and WO99/49154 PCT/AU99/00197 8 tile roofs. On unsheeted or uncovered roofs, the roof anchor shown in Fig. 2 may not be suitable. In another 5 embodiment of this invention, the roof fixing means 10 is in the form of a rafter clamp for use in such situations. A rafter clamp 30 is illustrated in Figs. 8-10 and comprises a member 31 of inverted channel section having a hook or loop 32 at its rear end for connection 10 to the safety rope 4. A toothed cam pawl 33 is located in a slot 34 in one side of the channel member 31, and is pivotally mounted on an upright pivot pin 35. A coil spring 36 is provided on the pivot pin 35 to bias the pawl 33 inwardly, i.e. clockwise when viewed from above. 15 A boss 37 is provided on the same side of the channel member 31 as the pawl 33. The boss 37 has a threaded through bore which receives a clamping bolt 38. The bolt 38 is preferably provided with a handle portion to enable it to be screwed into the boss 37 manually. 20 The rafter clamp 30 is designed to be fixed to a rafter member (whether it is a separate frame component or the top chord of a truss), or any similar roof frame member. The channel member 31 is dimensioned to receive the roof frame member therein. The fixing of the clamp 30 25 to a rafter is illustrated in Fig. 10. In a typical application, the clamp 30 is pushed down onto an exposed rafter or similar frame member 39 and in a forward direction, i.e. towards the bottom end of the rafter. This causes the toothed cam 30 surface of the pawl 33 to rotate against its spring bias and bite into the rafter, preventing rearwood movement of the clamp 30 relative to the rafter. The spacing between the side walls of the channel member 31 is wider than the rafter (in order to 35 comfortably accommodate different size rafters), but the biased pawl 33 urges the opposite side of the channel member 31 against the opposed side face of the rafter 39. The bolt 38 is screwed into boss 37 and against the WO99/49154 PCT/AU99/00197 9 rafter 39. This not only secures the rafter clamp to the rafter and prevents it from slipping off, but also ensures that the whole face of the opposite side wall of the channel member 31 is flush against its opposed side 5 face of the rafter 39. In this manner, the rafter clamp is aligned with the rafter, and the load applied to the rafter clamp acts longitudinally along the rafter. The removal of the clamp 30 is the reverse of the fitting procedure. Namely, the bolt 38 is manually 10 unscrewed, and the rafter clamp 30 is pushed forward (to bias the pawl 33 away from the rafter), and up (to lift the clamp off the rafter). It will be apparent to those skilled in the art that the roof clamp 30 possesses the advantages of the 15 roof anchor described above. In addition, the rafter clamp 30 has the advantage that it can be used on uncovered roof frames, or tiled roofs after removal of a tile to uncover a rafter, or other roofs having coverings which may not support the roof anchor. 20 The foregoing describes only some embodiments of the invention, and modifications which are obvious to those skilled in the art may be made thereto without departing from the scope of the invention. For example, the pawl 33 of the rafter clamp 25 may be replaced by a vice-like or over-centre clamping mechanism.

Claims (15)

1. A roof safety system having roof fixing means adapted to be fixed to a roof adjacent to one edge thereof, a harness adapted to be worn by a roof worker, 5 and a safety line connected between the roof fixing means and the harness, the safety line being, in use, of sufficient length to extend to the opposite edge of the roof, yet short enough to arrest the fall of a roof worker from the opposite edge. 10

2. A roof safety system as claimed in claim 1, wherein the roof fixing means is a roof anchor adapted to hook onto the bottom edge of the roof cladding.

3. A roof safety system as claimed in claim 2, wherein the roof anchor is of hook-like configuration. 15

4. A roof safety system as claimed in claim 3, wherein the hook-like configuration of the roof anchor is of variable size to accommodate cladding of different thickness.

5. A roof safety system as claimed in any one of 20 claims 2 to 4, wherein the roof anchor includes clamp means for fixing the roof anchor to the cladding.

6. A roof safety system as claimed in any one of claims 2 to 5, wherein the roof anchor is generally of T shaped configuration, having a shank portion and a 25 crosspiece, the crosspiece being adapted to be placed along the bottom edge of the roof cladding in use.

7. A roof safety system as claimed in claim 1, wherein the roof fixing means is a clamping mechanism adapted to be mounted to a roof frame member. 30

8. A roof safety system as claimed in claim 7, wherein the clamping mechanism includes at least one toothed cam member adapted to engage the frame member and resist movement of the clamping mechanism relative to the frame member under load. 35

9. A roof safety system as claimed in claim 7 or 8, wherein the clamping mechanism also includes clamp means for fixing the clamping mechanism to the roof frame member. WO 99/49154 PCT/AU99/00197 11

10. A roof anchor for use in a roof safety system, the roof anchor having a hook-like configuration and being adapted to hook onto the bottom edge of the roof cladding. 5

11. A roof anchor as claimed in claim 10, wherein the hook-like configuration of the roof anchor is of variable size to accommodate cladding of different thickness.

12. A roof anchor as claimed in claims 10 or 11, 10 wherein the roof anchor includes clamp means for fixing the roof anchor to the cladding.

13. A clamping mechanism for use in a roof safety system, the clamping mechanism being adapted to be mounted to a roof frame member, and having at least one 15 toothed cam member adapted to engage the frame member and resist movement of the clamping mechanism relative to the frame member under load.

14. A clamping mechanism as claimed in claim 13, further including clamp means for fixing the clamping 20 mechanism to the roof frame member.

15. A clamping mechanism as claimed in claim 13 or 14 and having a body of inverted channel section, the toothed cam member being pivotally mounted in one side of the channel section.