GB2104020A - Movable scaffold for buildings - Google Patents

Abstract

The scaffold car is suspended from two carriages (15, 16) joined by a cross bar (18), the carriages rolling inside a rail (10) suspended from support members mounted on the roof of a building. The cross bar (18) carries T-shaped safety brackets (21) the cross-piece (21b) of each of which runs inside the rail (10) and is of a width which exceeds the width of the gap (14) in the rail so that the car is restrained if a wheel shaft breaks. Lateral movements are effected by operating, from the scaffold car, an endless rope (33) cooperating with a grooved pulley (32), integral with a friction roll, which engages the undersurface of the rail (10). <IMAGE>

Description

SPECIFICATION Movable scaffold for buildings The present invention relates to a movable scaffold for buildings.

A movable scaffold generally comprises a scaffold car which is raised or lowered, as needed, along an exterior wall of a building by ropes and tackle usually attached to hooks fixed to the roof.

Since work is carried out from the car on a vertical face of a building it is necessary to shift the location of the hooks to enable work to be done on adjoining areas. As a result, considerable time is lost in shifting and rearranging the hooks together with their supports.

To overcome this problem, it is usual to suspend the scaffold car from carriages movable along a rail mounted on top of the building. In this case, the rail must be supported by means firmly anchored to the roof of the building. Such rails are generally made in several sections joined end to end so as to conform to the entire length of the building.

In the devices know hitherto, the rail generally comprises a cylindrical tube along which the carriages roll. The wheels, arranged on each side of the carriages, and rotate in planes which converge toward the bottom, one of the carriages having a driving wheel equipped with a rubber tyre frictionally engaging the upper surface of the rail and coupled to a pulley which is rotated by means of a rope from the scaffold car.

An arrangement of this type has serious drawbacks. To begin with, the converging planes of the wheels causes a pinching action on the rails, thus increasing to a considerable degree the force necessary to move the carriages. This convergence also subjects the wheel shafts to torsion. As a consequence, the total carrying load of the rail is reduced to a value less than the related value of the rail. Furthermore, the rails and the carriage wheels are exposed to foreign matter such as material fragments or by objects placed there unintentionally, such as boards, rods, tools, etc., thus impeding movement of the carriages.

To avoid the drawbacks mentioned above, U.S.

Patent No. 2. 178,956 provides for the use of a rail of U-shaped cross section with its opening directed downward and its arms bent inward so as to form a runway for the carriages.

To shift the scaffold car relative to the support rail, French Patent No, 1,297,234 provides for a winch with an endless cable and return pulleys at the ends of the rail, lateral movement being achieved by operating the winch. These means are relatively complicated and require return pulleys to be mounted at the ends of the rail and a cable to run along the entire length of the rail.

An object of this invention therefore is to provide a movable scaffold which is particularly well suited for work in horizontal sections along the outer walls of the buildings.

In accordance with this invention we provide a movable scaffold for use on buildings, wherein a scaffold car is adapted to be suspended from at least two carriages connected to each other by a removable cross car having a length approximately equal to that of said scaffold car, said carriages being movable along a rail formed by interlocking components mounted so as to overhang the top of the building by support members placed on the roof, said rail being Ushaped in cross-section with the ends of the arms bent inwardly and towards each other to provide tracks along which said carriages run within said rail; said scaffold being characterized in that near each end of the cross bar and connecting thereto a T-shaped safety bracket is located, the transverse bar of which is inside the U-shaped rail, perpendicularly to the longitudinal plane of symmetry of said rail, said transverse bar being wider than the spacing of the inward bent ends of arms of the rail.

In a preferred embodiment of the invention to be described in detail hereinafter, the rail is composed of any desired number of intermediate components of U-shaped cross-section each having one female end and one male end, one head component closed at one end and having a male other end, and one tail component closed at one end and having a female other end, each rail component being provided with means for suspending it from a support member, the suspension means being located within a short distance from its male end and from its closed end in case of the end section.

The rail components are mounted end to end to form a continuous rail by lowering the open mouth of one female end of U-shaped cross-section onto one male end, the female end having a part designed so as to rest on the upper surface of the male end and be locked thereto.

Movement is effected by pulling on either of the two cables fastened respectively to the ends of the rail and hanging vertically from the scaffold car after passing over a return pulley mounted on the corresponding carriage.

Movement of the suspension unit comprising the two carriages and their cross bar is effected by operating, from the scaffold car, an endless rope or chain trained over a grooved pulley journalled in the cross bar and coupled for rotation therewith to a friction roll having a rubber tyre or the like which engages the lower surface of the rail. Alternatively the friction roll may comprise twin wheels each of which engages a bent edge of each arm of the U-shaped rail.

The friction roll is carried by an arm pivoted to one end on the cross bar and subjected, at its opposite end, to the action of a spring which pushes the roll toward the bent edges at the underside of the rail.

Each support member has a plate which rests on the top of a wall; two converging arms fastened to the plate in a substantially vertical plane, two movable arms pivoted to the plate and converging to provide a support for a suspension member to support the rail and a rod for adjusting the position of the movable arms relative to the stationary arms.

Preferably the movable arms are welded to a shaft which is rotatably supported on the plate.

An anchoring head which comprises a plate with bent edges is welded to the end sections of the vertical stationary arms, the head carrying an anchoring ring for accommodating a cable, the anchoring head having a slot into which a sleeve at one end of the rod is inserted.

The adjusting rod has a handle at one end and is threaded in a tube which is fastened by means of a shackle to a short length of tube welded to the movable arms at a location near the ends thereof.

A safety chain is mounted between the short length of tube and the anchoring ring and the suspension member is formed by a rod bent at its ends with a curved depression at its centre.

Preferred embodiments of the invention will now be described more fully with reference to the attached drawings, wherein: Figure 1 shows an assembly of three types of components forming a rail to support a scaffold car; Figure 2 shows on a larger scale, an end view of a rail in which a carriage is supported; Figure 3 shows a unit formed by two carriages and a cross bar suspended beneath a section of rail; Figure 4 is a top view of the cross bar of the suspension unit shown in Figure 3 with an articulated arm carrying driving rolls; Figure 5 is a perspective view of a support member for a movable scaffold in accordance with this invention; Figure 6 is a detailed view of a suspension member; and Figure 7 shows a variation of the suspension unit shown in Figure 3.

Referring now to the Figures, a rail 10 (Figure 1) adapted for suspending therefrom and guidng a movable scaffold car along the wall of a building is formed by interlocking components mounted end to end in an assembly comprising a head component 11, any desired number of intermediary components 12 (only one shown in this example), and a tail component 13. Each component has at least one suspension means (11 a, 1 b, 1 2a, 1 3a), disposed in a manner to be explained further on, and adapted so as to be hooked to the overhanging ends of support members, as shown in Figure 5, mounted on the roof of a building.

All the sections of the rail are U-shaped in cross-section with the opening 1 4 between the arms facing downwards (Figure 2), the internal cross-section being substantially constant along the entire length of rail 10. The ends of arms (1 Oa, 1 Ob) are bent inwards and towards each other, preferably along an arc having a subtended angle cr greater than 90 . The internal surfaces of the bent sections form tracks for two carriages 1 5 and 1 6 each having at least two wheels 1 7 on each side thereof. The arc-shaped configuration of the bent sections encloses the bottom part of the treads of the wheels, which are thus guided without risk of the sides of the carriages touching the inner surface of the arms 1 Oa and 1 Ob of the rail.

The two carriages 1 5 and 1 6 are joined by a detachable cross bar 1 8 (Figures 3 and 4) the length of which corresponds to that of the scaffold car which is suspended from the carriages by suspension means 19 and 20 by tackles or similar means for fastening the scaffold car in a conventional manner.

Near each end of the cross bar 18 is a T-shaped bracket 21 a rigidly secured to the cross bar, the transverse bar of which 21 b is located inside rail 10, perpendicularly to the longitudinal plane of symmetry of said rail, and is wider than the opening 1 4. The brackets provide a safety factor for the suspension in the event of the shafts carrying the wheels of the carriage breaking.

Returning now to Figure 1, it is seen that, in addition to suspension means (1 1a, 1 ib or 12a or 13a), each rail section carries two members 22 on its upper surface such as rings or the like, so as to be able to handle the sections with the aid of hoisting means. The rail components are assembled end to end by lowering one female end down onto one male end. The female end of the next section is lowered onto the male end of a section already in place and locked thereto, In the example shown, male end 23 is free from any supplementary elements, with the exception of a stop 28 having a lug with an elongated hole. On the upper surface of the female end 24 of each section a bracket 25 is welded, whose overlapping part rests on the upper surface of the male end of the adjoining component.A stirrup 26 firmly welded thereon encloses the end portion of end 24, straddling the centre section of bracket 25, and projects longitudinally so as to straddle the end portion of end 23. At the same time, a stirrup 27, fastended in the vicinity of the protruding end of bracket 25, caps end 23, behind stop 28. The stirrup 27 has a lug 29 with an elongate hole, and a pin (not shown) to couple together the two sections of the rail. To assure rigidity it is preferable to provide a forced fit of stirrup 27 against stop 28. To facilitate this operation, bevelled faces 30 are provided in the lower portion of the flanges of the stirrup, on the side of the stop. Each intermediate component 12 must have one male end 23 and one female end 24, while head component 11 has one male end and is closed at its opposite end by a cap 31, and tail end 1 3 has one female end and one end closed by a cap 31.

The suspension means (here an inch) 11 a, 1 2a, 13a, are located in the vicinity of the male ends thereby supporting the junction between the male and female ends, the head component having a second suspension means 11 b near its closed end.

To laterally shift the suspension unit formed by the two carriages 1 5 and 1 6 and cross bar 18, each carriage has an idle pulley (not shown) of Vshaped configuration over which a cable passes which is fastened at one end to the corresponding end of rail 10 and whose other end hangs freely, vertically to the scaffold car.

However, this simple arrangement can only be made for a short length of wall. For longer walls, it is necessary to provide a more elaborate driving system. Such a system is shown in Figures 3 and 4, and comprises a friction roll with rubber tread or the like which engages the lower face of rail 10 and rotates with a pulley 32 journalled in the cross bar 18, the pulley having a trapezoidal groove for an endless rope 33, or notches for an endless chain for operation from the scaffold car.

In the example shown, the friction roll comprises twin wheels 34a and 34b keyed on the same shaft 35 as pulley 32 and engaging the under-surfaces of the bent sections of arms 1 Oa and 1 Ob of the rail. To assure a substantially constant pressure of wheels 34a and 34b on the under-surfaces of the bent sections of rail 10 and to compensate for wear of the treads, shaft 35 is journalled between cheeks 36a and 36b of a fork 36 pivoted at the free ends of the cheeks about a shaft 37 passing through a socket 38 carried by cross bar 18, and being subject at its opposite end to the action of a spring 39 urging that end toward the lower face of rail 10. Wheels 34a and 34b are mounted on shaft 35 between cheeks 36a and 36b and drive pulley 32 is located outside fork 36, on the shaft 35.Finally, an adjusting screw 40 acts on the fork 36 so as to disengage the wheels 34a, 34b from the rail 10, against the action of a spring 39, so that the suspension unit can be mounted by sliding it into one end of the rail prior to putting on cap 31, or by sliding it into the other end of the rail prior to assembling the adjoining intermediary component 12.

In place of a screw 40, other equivalent means may be used, such means constituting, for example, a connecting rod and cam unit with two stable positions, or a bevel-square type bolt, or a quick release lever so as to keep spring 39 in a compressed state during mounting of the carriages inside the rail and quickly releasing it immediately thereafter.

Referring now to Figure 5, it is seen that the support member for the scaffold car mainly comprise the following parts: a sole plate 101 with a front fiange 102, for placing on the top of a wall; two stationary arms 103 and 104 disposed in a substantially vertical plane, and being secured to the sole plate 101 by means of sleeves 105, 106, the arms converging so as to support an anchoring head 107; a movable U-shaped loop with splayed arms 108, 109, pivotable relative to the sole plate 101, by means of a shaft 110 passing through sleeves 105, 106 the bight of the loop at the end of the arms supporting a suspension member 111 from which is suspended the rail 10; and a rod 112 which adjusts the position of the movable arms 108,109 relative to the stationary arms 103,104.

The rod 112 has a driving crank 113, and is threaded in a tube 114 the lower end of which has a threaded shaft 11 5 of a shackle 11 6 passing through it, the shackle encompassing a support shaft 11 7 which is welded to the bottom of the converging ends of the splayed arms 108 and 109, the bight of the loop opposite the shaft 1 7 being bent relative to the arms 108 and 109.

The anchoring head 107 mainly comprises a plate whose edges are bent at right angles and welded to arms 103 and 104. The plate has secured thereto an anchoring ring 11 9 to which the end of a safety chain 120 is fastened, the other end of the chain 120 being fastened to support shaft 117. A cable 121 is fastened to ring 11 9 to provide a rear anchorage for the support member, said anchorage being effected by any known means to the roof of the building.

Anchoring head 107 has a slot 126 into which an end sleeve 127 of the threaded rod 112 is inserted.

Figure 6 shows how suspension member 111 is held on the bight of the loop extending from arms 108 and 109. The suspension member 111 comprises a round iron rod, for example, bent downwardly at both ends 122, and having a curved depression 1 23 at the centre which accommodates a support ring 124 for a rail 10 running along a wall, from which rail the scaffold car is suspended. The weight of the scaffold car, rail and carriages pulls the ring 124 down into the depression 123, holding the suspension member 111 down on the bight of the loop. Alternatively the suspension member may be welded or otherwise secured to the bight of the loop.

When the support member is mounted on a wall, sole plate 101 rests on the top of the wall and flange 102 rests against the front of the wall, stationary arms 103, 104 are in a substantially vertical plane, and the rear anchorage to the roof of the building is obtained by means of the cable 121 attached to ring 119. Threaded rod 112 is slid into the slot of anchoring head 107. After the rail 10 is hooked onto the suspension members 111 cranks 113 are operated so as to bring the rail to an even height over its entire length. If the mechanical connection between threaded rod 112, tube 114 and shackle or connecting link 11 6 becomes defective, the safety chain 1 20 prevents accidents.

When work is completed, the threaded rod 112 is taken out of its slot, movable arms 108,109 are fully raised against stationary arms 103, 104, and rod 112 is brought down along one of arms 108, 109 so that the support member can be accommodated within a relatively small space, be readily transportable, and be easily used for further work.

Referring now to Figure 7, identical elements are denoted by identical reference numbers. Cross bar 18 has here been simplified, carrying near one end thereof a spindle 52 on which pivots a bracket having a substantially horizontal arm 50 and a downwardly inclined arm 51. At the end of horizontal arm 50, a wheel 53 rotates on a spindle 54, while at the end of the inclined arm 51, a wheel 55 rotates on a spindle 56. From the wheel 55, an endless rope 57 is freely suspended to the scaffold car.

Wheels 55 and 53 are connected to each other by means of a chain 59. Wheel 53 has an outer lining 60 firmly adhering thereto, the lining consisting of a pneumatic tyre, for example.

The length of the inclined arm and the masses constituted by wheel 55 and rope 57 are such that wheel 53 is permanently engaged with the undersurface of the rail. Thus, simply by pulling on either end of rope 57, a lateral movement of the scaffold car is possible.

Claims (14)

1. A movable scaffold for use on buildings, wherein a scaffold car is adapted to be suspended from at least two carriages connected to eoch other by a removable cross bar having a length approximately equal to that of said scaffold car, said carriages being movable along a rail formed by interlocking components mounted so as to overhang the top of the building by support members placed on the roof, said rail being Ushaped in cross section with the ends of the arms bent inwardly and towards each other to provide tracks along which said carriages run within said rail; said scaffold being characterized in that near each end of the cross bar (1 8) and connected thereto a T-shaped safety bracket (21 a) is located, the transverse bar of which (21 b) is inside the U-shaped rail (10), perpendicularly to the longitudinal plane of symmetry of said rail, said transverse bar being wider than the spacing of the inward bent ends of arms (1 Oa, 1 Ob) of the rail.

2. A movable scaffold as set forth in Claim 1, being further characterized in that the components mounted end to end to form the rail (10) comprise end components and one or more intermediate components, the or each intermediate component having one female end (24) and one male end (23) shaped to fit snugly into the female end of an adjacent component, said female end having a part (25) which rests on the upper surface of the male end of the next adjacent component and is locked thereto, one of said end components having one female end and the other end component having a male end.

3. A movable scaffold as set forth in Claim 2, being further characterized in that the rail comprises a plurality of intermediate components (12) each having one male end (23) and one female end (24), one head component (11) closed at one end and having a male end at the other, and one tail end (13) closed at one end and having a female end at the other, each rail component being provided with a means (1 1a, 12a)for suspension from the support members, said means being located adjacent its male end or from its closed end for the end components (11 b, 1 3a).

4. A movable scaffold as set forth in any of Claims 1 through 3, for use on a short length of wall, being further characterized in that two cables are provided fastened respectively to the ends of the rail (10), and hanging vertically to the scaffold car after passing over a return pulley mounted on the corresponding carriage to move said carriages along said rail by pulling on either of said cables.

5. A movable scaffold as set forth in any of Claims 1 through 3, being further characterized in that there is provided an endless rope (33) or chain cooperating with a grooved pulley (32) journalled in said cross bar (18) and coupled for rotation with a friction roll having a tread of rubber or the like which engages the lower surface of the rail (10).

6. A movable scaffold as set forth in Claim 5, being further characterized in that the friction roll includes twin wheels (34a, 34b) which engage against the bottom of the bent edge of each arm (10a, Ob) of the rail (10).

7. A movable scaffold as set forth in any of Claims 5 or 6, being further characterized in that the friction roll (34a, 34b) is carried by an arm (36) pivoted to one end on the cross bar (18) and subjected, near its opposite end, to the action of a spring (39) pushing it toward the bent edges at the underside of said rail (10).

8. A movable scaffold as set forth in Claim 1, being further characterized in that each support member comprises a sole plate (101) for placing against the top of a wall; two converging arms (103, 104) fastened to the plate in a substantially vertical plane, two movable arms (108,109) pivoted to the sole plate and converging to provide a support for a suspension member to support the rail; and a rod (112) for adjusting the position of the movable arms in relation to the stationary arms.

9. A movable scaffold as set forth in Claim 8, being further characterized in that the movable arms (108,109) are welded to a shaft (110) which is rotatably supported on said sole plate (101).

10. A movable scaffold as set forth in Claim 8, being further characterized in that an anchoring head (107) is provided which comprises a plate with bent edges welded to the ends of the vertical stationary arms (103, 104), said head carrying an anchoring ring (119) for accommodating a cable (121).

11. A movable scaffold as set forth in Claim 10, being further characterized in that the anchoring head (107) has a slot (126) into which a sleeve (127) at one end of said adjusting rod (112) is inserted.

12. A movable scaffold as set forth in Claim 8, being further characterized in that the adjusting rod (112) has a handle (113) at one end thereof and is threaded in a tube (114) which is fastened, to a support shaft (117) fixed to said movable arms (108, 109).

13. A movable scaffold as set forth in Claims 10 and 12, being further characterized in that a safety chain (120) is mounted between said support shaft (117) and anchoring ring (119).

14. A movable scaffold as set forth in any one of Claims 8 to 12, being further characterized in that a suspension member (111) is provided in the form of a rod bent at its two ends and having a curved depression (123) at its centre, said rod being mounted across a loop formed between the extremities of the two movable arms.

1 5. A movable scaffold as set forth in any of Claims 1 through 3, being further characterized in that it has a bracket with two arms (50 51), pivoting around a spindle (52) carried by cross bar (18), one arm (50) of the bracket carrying a first wheel (53) fitted with a lining (60) firmly adhering thereto so as to engage the bottom of said rail (10), the second arm (51) of the bracket carrying a second wheel (55) rotatable by means of an endless rope (57), the first and second wheels (53 and 55) being coupled together and rotated by means of a chain (59).