US3058543A - Portable scaffolds - Google Patents

Description

Oct. 16, 1962 c. w. PRossER PORTABLE scAFFoLDs 5 Sheets-Sheet 2 Filed March 29. 1961 INVENTOR. CLYDE w. PROSSER BY M his ATTORNEYS Oct. 16, 1962 c. w. PRossER 3,058,543

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. .I l, f' 35 INVENTOR 'Il Il Vl CLYDE w. PRossER f @d "li BY j Illu Mae his ATToR/vEl/s United States Patent O 3,558,543 PORTABLE SCAFFULDS Clyde W. Prosser, 217 @riale Drive, Pittsburgh, Pa. Filed Mar. 29, 1961, Ser. No. 99,255 6 Claims. ('Cl. 182128) This invention relates to portable scaffolds and particularly to portable collapsible scaifolds for use in the interiors of vessels having variable internal dimensions.

The problem of removing and replacing the linings of bottle type vessels such as Bessemer converters, blast furnaces, LD. vessels, ladles and the like has been complicated by the lack of a satisfactory scaffold structure. Such vessels ordinarily vary in diameter from top to bottom and in some cases may be small at the top, large intermediate the top and bottom and small again at the bottom. The blast furnace is typical of such a structure. Other combinations of internal diameter may, of course, be readily found when such variations in diameter occur; the top work surface must, of course, vary in order that the workmen may be properly positioned with respect to the wall surface being worked on. This creates a problem of proper cantilever construction in order to support the work surface at the large diameters and yet be in a position to continue the scaffold to the smaller diameters. In the past, scaffolding such vessels for internal lining has been difhcult and expensive because of the need to build continuous scaffolding, first to remove the old lining, then to remove the scaffold piece by piece as the lining is removed and then to start again at the bottom to rebuild the scaffold.

The foregoing problems have long been recognized but no really satisfactory scaffold has heretofore been proposed. It has been proposed to overcome this difficulty by suspending xa platform on ropes which extend through the mouth of the vessel to a winch arrangement on a superstructure over the vessel. Such a structure is shown in lordan Patent No. 2,346,033, assigned to Bethlehem Steel Corporation. A modification of this structure is that of Putnam Patent No. 2,710,418. However, these scaffold structures require some `continuous suspension means extending through the vessel mouth; they are much less stable than a bottom supported scaffold; the likelihood of accident is greater and the upper Iworking surface is obstructed with support cables.

I have invented a scaffold structure which overcomes the aforementioned problems and which is simple, inexpensive and readily portable. Preferably, I provide an unobstructed work platform with a base, telescoping cylindrical support members, one about the other, with the cylinder of smallest diameter fixed to the base, a top main frame on the top of the cylinder of largest diameter, folding frame members on the main frame, flooring members removably on said frame, means for raising the cylinder successively and means for locking the bottom of one cylinder adjacent the top of the next inner cylinder.

In the foregoing general description, I have set out certain of the objects, advantages and purposes of my invention; other objects, purposes and advantages will be apparent from a consideration of the following description and the accompanying drawings in which,

FIGURE l is a vertical section through a furnace to be lined showing a preferred form of scaffold of my invention in lowest collapsed position;

FIGURE 2 is a vertical section of the furnace of FIG- URE l with the scaffold in partially raised position and extreme sections of platform removed to reduce the diameter of platform;

FIGURE 3 is a vertical section of the furnace of FIG- URE 1 with the scaffold in fully extended position, removable sections of platform removed and main floor beams folded at side of cylinder;

3,5,543 Patented Oct. 16, 1962 ICC 2 FIGURE 4 is a section on the line IV-IV of FIGURE 1 FIGURE 5 is an enlarged segmental section on the line V-V of FIGURE l and shows safety cage base in rst position;

FIGURE 6 is a segmental top plan view of the scaffold lift bar arrangement;

FGURE 7 is a segmental section at the top and bottom of adjacent segments showing the top and bottom rollers;

FIGURE 8 is a segmental section of the pawl and ratchet lift on the line VIII-VIII of FIGURE 5';

FIGURE 9 is a section of the pawl and ratchet lift on the line IX-IX of FIGURE 5;

FIGURE 10a is an enlarged segmental section through the walls of the hollow members showing the removable base bracket in second position;

FIGURE 10b is an enlarged segmental section through the walls of the hollow members showing the removable base brackets in a fourth position.

Referring to the drawings, I have illustrated a furnace 10 to be lined having a main body portion and a tapered neck. A scaffold base 11 is adapted to rest on the bottom of the furnace and is provided with radially extensible stabilizing arms 12 pivoted on posts 13 fixed to the base. The base is of a diameter 4small enough to enter the opening 14 at the end of the tapered neck. A plurality of cylinders 15, 16, 17, 1'8 and 19 held together by a series of removable pins 22a and telescoping one about the other are nested on the base 11. The larger cylinder 19 is provided with a lift bar 2o to receive a crane 2.1 whereby the entire unit may be inserted into the furnace and extended in the furnace. Each of the cylinders 15 through 19 are provided at top and bottom with cooperating openings 22 (top) and 23 (bottom) through which lock pins 23a may be inserted from the interior of the cylinders to hold the cylinders in extended position. The top of the outer cylinder 19 is provided with sixteen pairs ofY hinged arms 24 and 25 of different lengths, all adapted to fold against the sides of the cylinder. When extended these arms are adapted to receive removable gratings 26 and 26a and 2Gb which serve as a work surface. The length of short arms 25 is determined by diameter of platform at highest work level. The long arms 24 are provided with hinged end pieces 24a which may be pivoted down to the position shown in chain line in FIGURE 5.

When it is desired to use the scaffold the entire assembly is lowered through the opening 1'4 in the top of the furnace by crane hook 21. The stabilizing arms 12 are extended to engage the outer walls of the furnace. Arms 2d are raised to their extended position, pinned in place with knee braces Mb, and removable gratings 26, 26a and 26h are placed thereon. Stabilizers 24C are placed at platform level to bear against the furnace walls with rollers 24d. When it is necessary to raise the scaffold the hook 21 is lowered to engage lift bar Ztl, the top stabilizers 24e released, the 4-pins 22a are removed, and the nested cylinders are raised until the opening 22 in the top of the bottom cylinder and the opening 23v in the bottom of the next to bottom cylinder are approximately in alignment. The openings 22 are brought into precise alignment by hydraulic jack 27 mounted on top of a rack 2S slidable in a carrier Z9 carrying a pinion 30 in engagement with rack 28. The pinion 30 is on shaft 31a carrying a toothed ratchet wheel 32 engaged by a pawl 32a on the carrier 25a. When the openings 22 and 23 are aligned, the lock pins 23 are inserted. The lock pins are inserted from a safety cage 33 suspended in the center of the top cylinder and entered by a hinged cover 34 in the top grating. In order to facilitate movement of the several cylinders with respect to one another rollers 35 are provided on the bottom of each cylinder engaging the outer wall of the next smaller cylinder and rollers 36 are provided at the top of each external wall of each cylinder to bear on the inner wall of the next larger cylinder. This is repeated until the taper portion of the interior is reached. At this point the hinged ends 24a of the long arms 24 are dropped to a vertical position as shown in chain line in FIGURE gratings 26h are removed from the vessel. To extend work platform to top position the long arms 24 are dropped to side of top cyilnder and gratings 24h are removed from vessel.

The bottom of the carrier 29 is mounted on a beam 37 carrying the base of cage 30. A hand winch 38 mounted on carrier 29 in cage 30 is provided with a cable 38a reeved over a sheave 39 on the lift bar 20 and connected to a clevis 37b on beam 37. A-fter the pins 23 have been inserted to complete a raised section of the scaffold the beam 37 and with it oor of cage 30 is raised a distance substantially equal to the last rise in the scaiold and beam 37 is held by a removable bracket 40 inserted in holes 40a and 4Gb in the side wall of the cylinder next below the last one elevated.

In the foregoing specification I have set out certain preferred embodiments of my invention. It will be understood, however, that this invention may be otherwise embodied within the scope of the following claims.

I claim: v

l. A portable scalfold particularly adapted for use in vessels having an opening smaller than the interior diameter comprising a base adapted to pass through said opening, a plurality of hollow elongated members telescoping within one another, cooperating lock means on the top and bottom of each said member adapted to hold the bottom of one member adjacent the top of the next smaller Vmember in extensible position, support arms hinged at the top of the largest member adapted to be raised to the horizontal position and held there, removable grating means on said arms, rack means axially of s aid hollow elongated members suspended from the top member, adjustable beam means on the bottom of said rack selectively attachable to each member and jack means in the rack means whereby the top member may be adjustably positioned with respect to the other hollow members.

2. A portable scaffold particularly adapted for use in vessels having an opening smaller than the interior diameter comprising a base adapted to pass through said opening, a plurality of hollow elongated members tele scoping within one another, a lift beam at the top of the largest of said members, cooperating lock means on the top and bottom of each said member adapted to hold the bottom of one member adjacent the top of the next smaller member in extensible position, support arms hinged at the top of the largest member adapted to be raised to the horizontal position, locking means to hold said arms in the horizontal position, jack means suspended beneath the lift beam, rack means on the jack means extending axially of the hollow members, a guide tube reciprocable on the rack means, a pinion operably engaging the rack and held in position by a pawl and ratchet, adjustable base means on the guide tube selectively attachable to the interior of each hollow member and hoist means on the guide tube connected to the lift beam for lifting the adjustable base means and removable grating means on the arms forming a working platform.

3. A portable scaffold as claimed in claim 2 wherein the base means is held in removable brackets on the inlterior of each of the hollow members.

4. A portable scaiold as claimed in claim 2 wherein the hoist means is a winch on the guide tube having a cable passing over a sheave on the lift beam and anchored to the base means.

5. A portable scaffold as claimed in claim 2 wherein `the support arms are spaced apart circumferentially of the largest member and are of two lengths, each having a removable stabilizer on the end thereof adapted to bear against the interior of the vessel being worked upon.

6. A portable scaifold as claimed in claim 2 wherein stabilizer means are attached to the base and adapted to bear against the interior sidewalls of the vessel being worked upon.

References Cited in the le of this patent UNITED STATES PATENTS Hopfeld Aug. 9, 1960

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