US3220509A

US3220509A - Special purpose suspended staging

Info

Publication number: US3220509A
Application number: US325063A
Authority: US
Inventors: Sidney L Fisher
Original assignee: SPIDER STAGING Inc
Current assignee: SPIDER STAGING Inc
Priority date: 1963-11-20
Filing date: 1963-11-20
Publication date: 1965-11-30
Anticipated expiration: 1982-11-30

Description

Nov. 30, 1965 s. L. FISHER SPECIAL PURPOSE SUSPENDED STAGING 4 Sheets-Sheet 1 Filed Nov. 20, 1963 I NVENTOR.

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A rr a/P/vf Nov. 30, 1965 s. L. FISHER SPECIAL PURPOSE SUSPENDED STAGING 4 Sheets-Sheet 2 Filed Nov. 20, 1963 Nov. 30, 1965 s. L. FISHER 3,220,509

SPECIAL PURPOSE SUSPENDED STAGING Filed Nov. 20, 1963 4 Sheets-Sheet 4 E #2 I n P I k 55 t -;ili;f

4 72 INVENTOR.

j gym/5r z. HEM-76 2/ Z M 2 2 K Q United States Patent Ofiiice 3,220,509 Patented Nov. 30, 1965 3,220,599 SPECIAL PURPOSE SUSPENDED STAGING Sidney L. Fisher, Renton, Wash, assignor to Spider Staging, Inc Benton, Wasli., a corporation of Washington Filed Nov. 20, 1963, Set. No. 325,063 14 Claims. (Cl. 182142) The present invention relates to suspended stagings, and more particularly to suspended stagings that are especially adapted for use in working along a vertical pass on a vertically curved work surface, such as the welding of transverse seams on a submarine hull, for example. Certain specific aspects of the invention relate to provision in such a special purpose staging of means to maintain the staging in positive contact with and readily movable up and down work surface. Other specific aspects of the invention include means for accommodating a worker carried by the staging so as to be as comfortable as possible during extended work periods on variously angled work surfaces. Yet other aspects of the invention relate to the provision of means whereby such stagings can be used in tandem on a single work surface.

Suspended stagings for general purpose use are disclosed in Fisher US. Patent 2,112,837, and in Fisher US. Patent 2,998,094, for example. Stagings of this type are well adapted for use on a vertical work surface where free fall suspension alongside the work surface can be obtained, such as the side of a building, or tower, or the like. But free fall suspension of a staging is not satisfactory for performing work on an underhanging, vertically curved surface.

One prior approach to the specialized problem of maintaining a staging or the like alongside an underhanging, vertically curved work surface is disclosed in Tollefsen US. Patent 2,881,029. The Tollefson mechanism is specially designed for working on the exterior of a ship hull. It employs, in conjunction with a suspended staging, an outboardly directed, horizontally disposed telescopic arm made up of a plurality of tubular members sliding one within the other. The telescopic arm extends rearwardly of the staging and at its rear end is attached to a counterweight. A first cable extends from the top of the staging upwardly to one of a pair of winch drums mounted side by side and having the same axis of rotation. A second cable leads upwardly from the counterweight to the second winch drum. The two cables form the sides, and the telescopic arm the base, of an isosceles triangle, with the staging being located at the inside lower corner of such triangle. As the staging and the counterweight are raised or lowered the telescopic arm is moved in or out the extent necessary to place the staging contiguous to the curved work surface. There are several disadvantages inherent in the Tollefsen mechanism. The mechanism requires considerable outboard clearance. It is free to swing like a pendulum so the Workman cannot maintain a steady location or exert substantial force on the work surface. The extension and retraction of the telescopic arm must be performed by the workman on the staging, and the workman cannot give his full time and attention to his primary work task, but rather must divide his time between the primary work task and the operation of the telescopic arm.

A principal object of the present invention is to provide a method of and apparatus by which a suspended staging can be positively maintained contiguous to any generally vertical work surface and particularly to a partially underhanging, vertically curving surface. The

apparatus of the present invention is simple in construction and operation, maintains positive contact with the work surface, is adaptable to use with a wide variety of work surfaces, and in operation demands very little, if any, of the operators time away from the primary function or task he is called to perform in connection with the work surface. Briefly and in general terms, the apparatus of the present invention adapts a suspended staging for up and down travel in engagement with a work surface, even a vertically curved work surface, and for this purpose the apparatus comprises what may be termed a holding line or bounding line, maintained under tension and extending outboardly and both above and below the staging, with holding line engaging means on the staging which operates in conjunction with the holding line to maintain the staging against the work surface. The holding line is preferably simply a wire rope or cable, and exerts a force on the staging urging it toward the work surface in direct relation to the amount of tension maintained on the holding line. I

The holding line engaging means carried by the staging preferably comprises one or more loading members such as spring loaded sheaves adjustably arranged on and extending rearwardly of the staging. Preferably the sheave mounting means includes a resilient loading member in the form of a torsion spring adapted to actively and positively urge the associated sheave against the holding line. Preferably, also, the holding line is installed so as to be of fixed length and anchored both above and below the staging. Suitably, part of the tension placed in the holding line can be generated at the time it is installed, with an increase in tension being imparted to the holding line by adjustment of the loading member(s). Owing to the construction and arrangement of the sheave loading members, as tension is put into the holding line, holding line tensioning energy is stored in the loading members and the loading members are to a degree selfadjusting to maintain the holding line tension reasonably constant throughout the course of travel of the staging on the curved work surface.

According to the preferred form of the invention, each of the sheave loading members comprises a torsion bar spring and is constructed in a manner making it possible for the operator, from his position on the suspended staging, to himself adjustably set the torsion bar by hand and change the amount of loading.

A further principal object of the present invention is to provide a method of and apparatus for adapting a plurality of vertically related staging units for travel contiguous to a curved surface, involving the use of a single tensioned holding line extending in a generally vertical plane rearwardly of said staging units and contacting line engaging means oneach of them. According to this aspect of the invention, the suspension line of each lower staging unit can extend upwardly and pass through its own fairlead and also through the fairlead(s) of the staging unit(s) disposed above it.

Additional objects and advantages of the present invention involve the provision in special purpose suspended staging of some or all of the following features:

(a) an operators cage on the staging including a seat in the rear thereof, preferably hinge mounted along its rear edge to the frame of the staging, so as to be movable up from a generally horizontally in use position to a generally vertical inoperative position, out of the way of the operator when he is standing in said operators stage;

(b) tool rest means extending between and mounted for up and down movement on a pair of parallel, generally upright forward post members constituting forward components of the operators cage;

(c) a control panel for the motive means, such as a reversible electric motor, for driving the Winch drum on which the suspension cable is wound, said control 3 panel preferably being attached to said tool rest means so as to be in easy reach of the operator at all times;

(d) back rest means extending between and mounted for up and down adjustment on a pair of parallel substantially upright rearward posts, constituting rearward components of the operators stage;

(e) arm rest means mounted on at least one of the forward posts, including means adjustably mounting said arm rest means for both up and down movement along the post(s) and for in and out angular movement thereabout;

(f) heat shield means disposed forwardly of the operators cage so as to be between the operator and the work surface;

(g) air circulating means, such as a blower or fan, mounted on said staging at a lower rearward location with respect to the operators cage and arranged to blow cooling air into the operators cage and generally toward the heat shield means, such heat shield means deflecting the cooling air upwardly and past the operator;

(h) upper and lower pairs of inboardly directed, work surface contacting wheels, mounted on the staging frame and riding on the work surface with the lower pair of wheels being non-swivelly journalled to said frame and with the upper pair of wheels being swivelly journalled to said frame for ease of tracking, said wheels preferably consisting of aluminum disks, having beveled peripheral side portions and a relatively narrow peripheral rim portion therebetween, such relatively narrow rim providing a relatively narrow line of contact with the heated work surface, lessening heat conduction from the work surface to the staging through the wheels, with said wheels being perforated radially inboard of their rims, so as to increase dissipation of heat absorbed from the work surface; and

(i) adjustable frame components whereby the swivel axes of the upper pair of work surface contacting wheels of the staging can be adjustably varied and readily maintained in substantial alinement with radii of the curved work surface.

These and other objects, features, characteristics and advantages pertaining to and inherent in the present invention will be apparent from the following description of certain typical and therefore non-limitive embodiments thereof, as illustrated in the accompanying drawings, wherein like numerals refer to like parts, and wherein:

FIG. 1 is a perspective view taken from above and toward the rear and one side of a suspended staging, incorporating typical embodiments of various component arrangements characterizing the present invention;

FIG. 2 is a perspective view of the staging shown in FIG. 1, taken from above and toward the front and one side of the staging;

FIG. 3 is a side elevational view of the staging shown in FIGS. 1 and 2, showing the same in a substantially upright position as it moves upwardly in close proximity to a submarine hull, and showing an operator welding a vertical seam from a sitting position, to illustrate a typical working operation;

FIG. 4 is a side elevational view similar to the view of FIG. 3, but presenting the staging in a backward leaning attitude as it moves downwardly in close proximity to the convex work surface, such view showing the operator in a back supported reclining position while welding below an overhanging portion of the submarine hull;

FIG. 5 is a rear elevational view of the staging illustrated in FIGS. 1-4;

FIG. 6 is a front elevational view of the staging illus trated in FIGS. 1-5;

FIG. 7 is a top elevational view of the staging illusstrated in FIGS. 1-6;

FIG. 8 is a view partly in section and partly in elevation of a torsion bar spring assembly, representing a typical embodiment of the sheave loading means characterizing the present invention;

FIG. 9 is a somewhat simplified side elevational view of three suspended stagings arranged in tandem and urged toward a submarine hull by a single holding line; and

FIG. 10 is a fragmentary enlarged scale view of one of two end fittings illustrated in FIGS. 14 and serving to adjustably mount a tool rest and a control box attached thereto onto a portion of the staging frame.

Referring now to the drawings in more detail, the special purpose staging shown comprises an operators cage 10 having a deck 12, and a suspension line compartment 14 situated behind the operators cage 10.. A fixed guide or fairlead 16, through which is led a suspension line 18 on which the staging is suspended, is mounted atop suspension line compartment 14. A winch unit 20 is mounted at the bottom of compartment 14, and the suspension line 18 is woven upon the power-driven winch drum thereof.

In a single cable suspended staging of the type herein disclosed, safety and reliability of operation are extremely important. In this respect it is vital that the suspension line 18 spool onto the winch drum of winch unit 20 compactly and levelly, that the take-up and let-out of the suspension line 18 progress evenly, and that no undue wear of the suspension line 18 occurs. Thus, the winch unit 20 is preferably of the level-winding type disclosed and claimed in my prior US. Patent No. 2.998.094.

The winch drum of winch unit 20 is preferably driven by a variable speed, reversible electric motor 24 mounted in the lower portion of compartment 14 closely adjacent to the winch mechanism 20 and suitably drivingly connected thereto by gear reduction means 21. The control circuit for the electric drive motor 24 is carried up to the control panel 22 on which a double pole double throw reversible switch 26 or the equivalent is provided. The switch 26 may be thrown to one side to drive the motor in the forward direction or by throwing the switch over to the other side the motor may be driven in a reverse direction, as is common practice to control direction of rotation of reversible motors. Preferably, a rheostat is provided in series between the switch 26 and the motor 24 and is controlled by a suitable knob 28 extending out from the front of the control panel 22. This rheostat may be used for varying the rotational speed of the electric motor and the winch drum so as to in turn vary the rate of up or down movement of the staging. In use of the staging in a welding operation, for example, wherein the operator is welding a seam in a vertical plane, the operator 0 by throwing the switch 26 to its up position provides current to the motor 24 to drive the winch drum and in turn cause the staging to move upwardly. The rheostat may be adjusted so as to coordinate the rate of upward movement of staging with the speed at which the welding seam can be formed. The operator 0 then merely supports his hand-held welding torch T on the tool rest 30 located in front of him, moving laterally across the seam as necessary, and letting the staging movement provide the vertical movement that is necessary to the Welding operation.

In accordance with the present invention, the staging is urged toward and adapted to move vertically in close proximity to the convex work surface 32 by means of a holding line or cable 34, situated rearwardly or outboard of the staging and riding in the peripheral groove of one or more loading members in the form of spring loaded sheaves mounted on and disposed rearwardly of the staging. As will become apparent, the holding line or cable 34, which might also be termed a bounding line, retention line, guide line, or track line, functions to confine or restrain the travel of the staging to a path along and in contact with the curved work surface. In the preferred form of the invention, two sheaves are employed, an upper sheave designated 36 and a lower sheave designated 38. Sheaves 36, 38 are each spring mounted and adapted to be both positively and reactively urged into engagement with the hold line 34, as will hereinafter be explained in more detail.

Assuming, for example, that the staging is in operating relation with the convex work surface such as the side 32 of a submarine hull, the holding line 34 is arranged to extend entirely around such hull and be connected together at its ends by a suitable coupling assembly, such as an eye ring and shackle coupling as sembly 40, for example, as illustrated in FIG. 9. The holding line 34 may be first put in tension before its ends are coupled together at 40. This may be suitably done by computing the length of cable necessary to surround both the submarine hull and the staging (or quite possibly several stagings, as will hereinafter be described in connection with FIG. 9), taking into consideration any nominal stretch of the cable, and then subtracting from the cable length thus computed at short portion thereof representing a desired amount of strain to be put into the cable. The two ends of cable 34 are then drawn together (by suitable cable tensioning equipment, not shown) and coupled. This puts holding line 34 in tension and positively urges the same against the grooved peripheries of

sheaves

36, 38, causing the loading of spring elements incorporated into and forming portions of the mounting means for

such sheaves

36, 38, and presently to be described.

As clearly shown in FIGS. 3 and 4, line 34 angles around the

sheaves

36, 38, riding in the peripheral grooved portions thereof, and slopes inwardly toward the work surface 32 both above sheave 36 and below sheave 38. As is apparent, the tensioned line 34 presses against the

sheaves

36, 38 and positively urges the staging into close proximity with the convex work surface 32, regardless of the attitude of the staging. As illustrated, upper and lower sets of

wheels

42, 44 and 46, 48, respectively, are disposed inboardly of the staging, and as the same is raised or lowered,

such wheels

42, 44, 46, 48 prevent the staging from marring the side of the work surface 32 and from being marred by the Work surface 32. These

Wheels

42, 44, 46, 48 may of course also serve as a means by which the staging unit may be trundled on the ground while moving the same from place to place.

The type of staging illustrated in the accompanying drawings is especially adapted for girth welding operations or the like incident to submarine hull fabrication, where the work surface often is at temperature of about 300 F. or more. With a heated work surface of this nature, heat dissipation by the working equipment in contact with the surface and shielding of the equipment operator from the heat, at least to some extent, can be serious practical problems. To minimize heat transfer,

Wheels

42, 44, 46, 48 are preferably constructed from aluminum and include a plurality of heat dissipating openings 49, as illustrated in FIGS. 1-4. By way of typical and therefore non-limitive example, the heat dissipating openings 49 may measure one and one-half inches (l /2") in diameter for an eight inch (8) wheel diameter and a wheel thickness of one-half inch /2). The

Wheels

42, 44, 46, 48 preferably have relatively narrow rims so as to create a relatively short line of wheel contact with the work surface 32, minimizing heat transfer from the work surface 32 to the

wheels

42, 44, 46, 48. As perhaps best illustrated by FIG. 7, the relatively narrow rims on the

wheels

42, 44, 46, 48 are suitably formed by beveling the peripheral side portions of said wheels. Aluminum is a good conductor of heat and the heat that is transferred to the

wheels

42, 44, 46, 48 from the work surface 32 is promptly evenly distributed and then dissipated by heat radiation and direct transfer from the side surfaces of the wheels and the surfaces formed by the openings 49 to the surrounding air.

In the preferred form of staging illustrated, the

sheaves

36, 38 are mounted for rotation between the tines of

forks

50, 52 which are welded or otherwise suitably attached to the outboard ends of

lever arms

54, 56, re-

spectively. The inboard end of lever arm 54 (note FIG.

8, for example) is rigidly secured to the midportion of a horizontally extending tubular mounting member 58 journalled at its ends by means of

trunnions

60, 62 anchored to upstanding

tubular components

64, 66 of the suspension line compartment 14. In like fashion, lever arm 56 is secured to the midportion of a tubular mounting member 68 journaled at its ends by means of

trunnions

70, 72 anchored on a lower frame portion of the staging unit. Torsion bar springs 74, 76 extend axially through the tubular mounting

members

58, 68. As shown in FIG. 8, in connection with the mounting assembly for sheave 36, chosen for sake of example to show certain constructional details common to both of the mounting assemblies, one end of mounting member 58 is constructed to engage the correspondence end 80 of the torsion bar 74 and retain the same against relative rotation. The opposite end of torsion bar spring 74 makes a right angle bend and extends for a distance as a lever 82. In similar fashion torsion bar 76 includes a lever 84. If desired, handle

grips

86, 88 may be provided at the terminals of

levers

82, 84. Returning to FIG. 8, the

trunnions

60, 62 mount the tubular mounting member 58 for free rotation relative to the staging unit frame unless such is otherwise prevented. The torsion bar spring 74 is rotatively supported within the left end of tubular support member 58, as pictured, by means of a suitable heat resistant siliconized polymeric bearing or bushing 90, preferably of Nylatron or like consistency. Thus, as pictured in FIG. 8, the left-hand end portion of torsion bar spring 74, immediately prior to where it makes the right angle turn and extends as lever 82, is free to rotate relative to the surrounding tubular member 58, unless otherwise prevented from doing such, while the right-hand end of the torsion bar spring 74 is affixed to the tubular support member 58 and is not free for relative rotation. Referring now to FIGS. l-4, for example, the upper end of lever 82 is shown engaged in one of a plurality of notches formed in a notch bar 92 anchored to a portion of the staging unit frame. Let it be assumed that lever arm 82 is in its illustrated position, that holding line 34 is riding in the grooved periphery of sheave 36, and that holding line 34 is in tension. As pictured in FIG. 3, for example, the holding line 34 exerts a force on sheave 36 tending to rotate it about the tubular mounting member 58 in the clockwise direction. However, since lever 82 is anchored on the staging unit frame by notch bar 98, and further since the end of the torsion bar spring 74 distal the notch bar 92 is firmly secured to the tubular mounting member 58, free rotation of the sheave and its mounting

members

54, 58 is prevented. However, the force exerted by holding line 34 on sheave 36 is transferred through the fork 50, the lever arm 54, and the tubular mounting member 58, all of which are of a relatively rigid or inflexible construction to the torsion bar spring 74 and causes the same to twist somewhat. The torsional deformation or twisting of torsion bar spring 74 permits sheave 36 to swing clockwise slightly. As it twists, torsion bar 74 is storing up energy and constitutes a continuing force biasing the sheave 36 into engagement with line 34. The spring mounting of the

sheaves

36, 38 lessens the significance of the length of holding line 34, and if for any reason the holding line 34 loses some of its tension and tends to slacken somewhat, the stored energy in the torsion bar springs 74, 76 is partially released and maintains the tension in holding line 34.

As will be apparent, the amount of stored energy in the torsion bar springgs 74, 76 can be readily adjusted by shifting the

levers

82, 84 into different notches in the notch bars 92, 94, respectively. Thus, for example, with lever arm 82 engaged in the uppermost notch bar 92, and with holding line 34 engaged in the peripheral groove of sheave 36 and, relatively speaking, holding sheave 36 against appreciable movement, when lever 82 is disengaged from the uppermost notch and moved downwardly the torsion bar Spring 74 is twisted or wound up an amount generally proportional to the extent of downward movement of lever 82. This increases the stored spring energy in torsion bar spring 74 tending to urge sheave 36 into engagement with line 34. This type of stored energy put into torsion bar spring 74 by change in position of lever 82 may be termed positive spring energy, while the stored energy produced when torsion bar spring 74 is twisted by the force of cable 34 may be termed reactive spring energy. Of course, regardless of how it is done, the twisting of torsion bar spring 74 creates a reaction force urging the

wheels

42, 44, 46, 48 of the staging into constrained contact with the work surface 32.

The staging preferably comprises a framework of integrally welded, heat-treated aluminum alloy tubing. The operators cage 10 is formed between forward and rearward pairs of

posts

96, 98 and 100, 102, respectively. For reasons explained below, the

posts

96, 98 should be parallel to each other and the

posts

100, 102 should be parallel to each other, but although desirable, it is not essential that the

posts

96, 98 extend parallel to the

posts

100, 102. As shown in FIGS. 1 and 2, for example, control box 22 may be mounted on the tool rest 30 so as to be conveniently located in front of the operator. The tool rest 30 is mounted for up and down movement for adjustability along the

posts

96, 98, preferably by means of

end fittings

104, 106, generally of T shape and including sleeve portions 108, 110 surrounding the

posts

96, 98. The inside diameter of sleeve portions 108, 110 is slightly larger than the outside diameter of

posts

96, 98, leaving

fittings

104, 106 and tool rest 30 free to slide along the

posts

96, 98 unless locked against such movement by means of set screws 111, 113 (FIG. 10).

Posts

96, 98 may also mount a pair of arm rests 112, 114, as illustrated in FIGS. l-7 of the drawings. The mounting means for the arm rests 112, 114 may comprise T fittings like the

fittings

104, 106 described above, and may include set screws 115, 117. As is apparent, the arm rests 112, 114 may be pivotally moved horizontally as well as vertically adjusted relative to the

posts

96, 98. Adjustment is effected by merely loosening the set screws 115, 117, and swinging the arm rests 112, 114, together or individually, in and out and/or sliding the same up or down the

posts

96, 98.

When the staging is in or near an upright position, such as illustrated in FIG. 3, for example, the operator may desire to work from a sitting position in which case the tool rest 30 and arm rests 112, 114 are suitably adjusted to occupy relatively low positions on the

posts

96, 98. The operator sits on the seat 120, rests his arms on the arm rests 116, 118 and his hands on the tool rest 30, steadying the tool which he holds, e.g. welding torch T, on the tool rest 30. The back of the workman may be supported by means of back rest 122 or he may be leaning forwardly. The back rest 122 is mounted on the

posts

100, 102 for vertical adjustment therealong. The adjustable mounting means for the back rest 122 can suitably take the form of a pair of straps 124, 126, each including a buckle disposed behind the back rest 122. Of course, adjustment of the back rest 122 is effected by loosening the buckles, then moving the back rest 122 up or down to the desired position, and finally retightening the buckles.

During those stages of the welding operation wherein the staging occupies a rearwardly leaning attitude, the operator may desire to work from a back supported reclining position, such as illustrated in FIG. 4. In such case the tool rest 30 and arm rests 116, 118 are adjusted upwardly along the

posts

96, 98, and back rest 122 is adjusted upwardly along the

posts

100, 102 to the respective positions illustrated in FIG. 4. Also, the seat 120, which is hinged along its rear edge, at locations 126, 128, for example, is swung upwardly from an in use to an inoperative position so as to place it out of the operators way. Obviously, the vertically adjustable tool rest 30, the

vertically and horizontally adjustable arm rests 112, 114, the vertically adjustable back rest 122 and the hinge mounted seat 126 may be selectively employed in a variety of ways differing from what has been described, at the choice of the operator.

In further consideration of operator comfort, in staging units especially adapted for welding operations, a heat shield 132 is located forwardly of the operator 0 and fixed along its sides and top and bottom to the staging frame. The heat shield 134 shields the operator 0 from being overly heated by the radiation of residual heat in the metal behind the welding torch. Also, owing to the presence of heat shield 132, some of the residual heat will be removed from the space formed between heat shield 132 and work surface 32 by convection. The warm air in such space rises and is continually replaced by upwardly flowing cooler air, such cooler air picking up and removing some of the residual heat as it moves over and past the heated areas of the work surface. Also provided for operator comfort, a fan 134 is located below and slightly to the rear of seat and is adapted to blow air forwardly toward the heat shield 132. The heat shield 132 serves to divert such air upwardly past the operator and through the work station. The seat 120 is preferably constructed of expanded sheet metal or the like so as to be perforate and able to pass rather than block the flow of the air from fan 134.

Referring now to FIGS. 1-4, the lower set of

wheels

46, 48 are preferably mounted by non-swiveling, straight tine,

wheel forks

136, 138, respectively, secured to forwardly projecting end portions of frame components 140, 142, respectively. The upper set of

wheels

42, 44 are preferably swivel mounted by means of offset

forks

144, 146 journalled onto the respective ends of support bars 148, 150. As most clearly illustrated in FIGS. 1-4, the support bars 148, 150 may be pivotally mounted onto the staging frame by means of

hinge fittings

152, 154, similar or identical in construction to the

fittings

104, 106 mounting the tool rest 30 and the control box 22 for vertical movement, or the

fittings

116, 118, mounting the arm rests 112, 114 for both horizontal and vertical adjustment. As shown in FIGS. 1-4, for example, each of

posts

96, 98 makes right angle turns and extends rearwardly as

frame sections

156, 158 to intersect and be joined as by welding to the

posts

100, 102, respectively, for example.

Anchor plates

160, 162 extend generally upright from and are welded along their bottom edges to frame

sections

156, 158.

Such anchor plates

160, 162 each contains a plurality of

openings

164, 166, respectively, arranged in circular arcs having their loci at the pivotal center of

fittings

152, 154. The

wheels

42, 44 and their support bars 148, 150 may be adjusted angularly along vertically extending arcuate paths, by selectively bolting the

support arms

148, 150 to the

anchor plates

160, 162. The

forks

144, 146 have arcuate tines, offsetting the rotational axes of the

wheels

42, 44 to one side of the swivel axes of the

forks

114, 146. The

wheels

42, 44, due to their offset mounting, readily make a 180 change in direction when the direction of travel of the staging unit is reversed, and when the swivel axes of forks are substantially normal to the work surface, i.e. in substantial alinement with radii of the work surface. As will be apparent, the

wheels

42, 44 are adapted to the particular curvature of a given work surface by adjustably atfixing the support bars so as to make the swivel axes of

forks

144, 146 extend substantially normal to the points of contact of

wheels

42, 44 with the given work surface.

Fairlead 16 consists of a pair of generally parallel, elongated rollers 168, 170, end mounted for rotation in a box frame 172. The suspension cable 18 extends between the rollers 166, and in at least most instances rests against and is supported by the forward roller 168. The space between rollers 168, 170 is sufiiciently wide to accommodate several other lines in addition to suspension line 18, for reasons hereinafter presented.

It may be desirable to use a plurality of staging units in concert, as illustrated in FIG. 9, wherein a plurality of such staging units, arranged in tandem or in tier, are illustrated, three being shown by way of example. Owing to the unique construction and arrangement of the staging equipment incorporated in the suspended staging characterizing the invention, it is possible to use a single outboard holding line 34 for urging all of the tandemly arranged stagings into close proximity with the convex work surface. In the arrangement shown at FIG. 9, the work surface is in the nature of a portion of the side surface 32 of a submarine hull and the line 34 extends entirely around such hull and is coupled together at its ends at location 40. Preferably line 34 is put into tension prior to the coupling together of its ends. Line 34 exerts an inward component of force on the

sheaves

36, 38, 36, 38', 36", 38", reactively loading the torsion bar springs incorporated into the mounting means for the

sheaves

36, 38, 36, 38, 36", 38".

In this arrangement, involving a plurality of tiered staging units, the suspension line of each lower staging unit extends through the fairlead rollers of each of the staging units situated above it. Each staging unit is also provided with a lower pair of elongated guide rollers, mounted on a lower portion of its framework, substantially equal distance from the work surface 32 as the fairlead rollers 168, 170. Referring to FIG. 9, the suspension cable 18 of the lowermost staging unit extends from the winch unit 20, up through fairlead 16, next through the lower guide roller means 174 on the middle staging unit, then through the fairlead 16' of such middle unit, through the lower guide roller means 176 of the uppermost staging unit, and finally through the fairlead 16" of such upper staging unit. Suspension line 18 is shown anchored to an upper portion of the submarine hull by means of an eye pad 178. Suspension cable 18 extends from winch unit 20' of the middle staging unit upwardly through fairlead 16' of such middle staging unit, next through the lower rollers 176 of the uppermost staging unit, and then through the fairlead 16" of such upper staging unit before being anchored at eye pad 180, shown mounted on the submarine hull. The suspension cable 18" for the uppermost staging unit extends from the winch unit 20" of the upper staging unit and then through the fairlead 16" of such upper staging unit before being anchored to the submarine hull at eye pad 182.

Specific variations or modifications in suspended staging equipment characteristic of the present invention include providing the staging with a heat shield extension secured along its upper edge to the tool rest 30 and depending from said tool rest 30 downwardly in front of and overlapping the stationary heat shield 132. This arrangement provides a greater amount of protection for the operator particularly when the tool rest 30 is in an up position, as shown by FIG. 4 (the up position but not the heat shield extension). Also, the holding line 34 may be end supported in a variety of ways. For example, one end may be atfxed to a solid support and the other end wrapped onto a winch drum employed for putting line 34 in tension. Or, each end of line 34 may be anchored to the work surface by means of an eye pad.

While the aspects of the present invention which relate to the positioning of a suspended staging in proximity to a work surface have been particularly described and illustrated with respect to a vertically curved, partially underhanging Work surface such as a submarine hull, it will be understood that the tensioned holding line and associated components characteristic of the invention also have utility and afford certain operational advantages when employed with a suspended staging on other work surface configurations. Thus, by way of additional example, a tensioned holding line can be used with a suspended staging operating along an essentially flat and more or less vertical work surface, to maintain the staging in positive contact with the work surface and reduce any undue swaying thereof as might be encountered under windy conditions or where the Work being performed involves generation of substantial lateral forces between the staging and the work surface, such as when chipping or drilling.

While the special purpose staging illustrated and discussed in detail above has been described in relation to a Work operation of the welding type, it will be readily recognized that various features of the invention are readily adaptable to staging used for other work operations involving suspended staging movement along and in contact with a vertically curved work surface. Typical of such other types of work operations are painting, chipping, scraping, sandblasting, grinding, drilling, cutting, and inspecting, for example.

From the foregoing, various other component arrangements and modes of utilization of the suspended staging equipment characteristic of the invention will be apparent to those skilled in the art to which the invention is addressed, within the scope of the following claims.

What is claimed is:

1. In combination; a portable staging suspended by a cable and adapted for up and down travel relative to a work surface, said staging comprising: a deck; frame means extending upwardly from said deck and forming a work station; a sheave disposed rearwardly of the work station; a line in tension, extending both above and below said staging, said line in tension angling around the rearward portion of the sheave, in contact therewith, and sloping towards the work surface both above and below the sheave; and means mounting said sheave onto the frame for rotation in a substantially vertical plane, said latter mentioned means including a horizontally disposed torsion bar spring for urging the sheave into tensional engagement with the line.

2. A suspended staging specially adapted for up and down travel relative to a vertically arcuate work surface of convex curvature, said staging including; a deck; frame means extending upwardly from said deck; a pair of laterally spaced trunnions on said frame; a generally horizontally disposed tubular member journalled by said trunnions; a sheave spaced outwardly from said tubular member; means supporting said sheave for rotation in a plane extending generally perpendicular to the axis of the tubular member; means interconnecting said tubular member and the sheave supporting means; a torsion bar extending partly inside and partly outside of said tubular member; means connecting one end of said torsion bar to the adjacent end of the tubular member; and means securing the opposite end of the torsion bar to the frame of the staging unit.

3. A suspended staging according to claim 2, wherein the portion of the torsion bar lying outside of the tubular member extends at an angle to the remaining portion of said torsion bar, situated inside the tubular member, and wherein the means securing an end of the torsion bar to the frame comprises a notch bar attached to the frame, and having a plurality of notches into which the said opposite end of the torsion bar may be selectively located.

4. A suspended staging adapted for up and down travel contiguous a vertically arcuate work surface having a convex curvature, such staging including a deck having a front edge and a rear portion, frame means extending upwardly from said deck and defining an operators work station, said frame means including a seat supporting portion situated generally above the rear portion of the deck and a pair of parallel, generally upright forward posts extending above the forward edge of said deck, a seat, means mounting said seat onto said seat supporting portion for movement from an in use position wherein said seat extends generally parallel to the deck to an inoperative position wherein the seat extends generally perpendicular to the deck, a tool rest extending between said forward posts, and means mounting said tool rest for reciprocal up and down movement along said forward posts, such that the tool rest can be adjusted to a relatively low position when the seat is in its position of use and the operator is sitting down and is movable to a relatively high position when the seat is in its inoperative position and the operator is essentially standing or reclining.

5. A suspended staging according to claim 4, wherein the frame further includes a pair of parallel, substantially upright, rearward posts disposed rearwardly of the forward posts and extending above the rear portion of the deck, wherein a back support extends between said rearward posts, and wherein the staging further includes means mounting said back support onto said rearward posts for up and down adjustment therealong, such that the back support may be adjusted upwardly when the tool rest is adjusted upwardly and the seat is in its inoperative position, and at such time used by the operator as a principal support for his body.

6. A suspended staging according to claim 4, wherein an arm rest extends inwardly from at least one of said forward posts, and wherein the staging further includes means adjustably mounting said arm rest for up and down movement along the post and for in and out angular movement thereabout.

7. A suspended staging according to claim 4, further comprising winch means secured to a lower portion of the frame and carried by the staging, said winch means including a winch drum, a reversible, variable speed electric motor drivingly connected to the winch drums, a suspension cable windable onto said winch drum and extending upwardly therefrom to an overhead anchorage, and control means for said electric motor including a control box secured to the tool rest, switch means on said control box for controlling the direction of rotation of the motor, and means on said control box for controlling the rate of rotation of the motor.

8. In combination, a portable staging; suspension line means for suspending said staging alongside of a work surface, and supporting it for up and down travel relative to said work surface, said suspension line means being secured at one of its ends to said staging and its other end to an overhead anchorage means; and means for holding said staging into close proximity with the work surface, both when it is moving and when it is stopped, said means comprising: tensioned holding line means separate from said suspension line means, and line engaging means on said staging, said holding line means extending both above and below said staging, in a generally vertical plane, and angling around said line engaging means, and being in relative moving contact therewith during movement of the staging, and extending toward the work surface both above and below the staging, said holding line means exerting an inward force on said line engaging means, and in that manner holding the staging into close proximity with the work surface.

9. In combination, a portable staging suspended at the lower end of a cable, the upper end of which cable is secured to an overhead anchorage means, said cable supporting the staging for up and down travel relative to a work surface, said staging comprising a deck, frame means extending outwardly from said deck and forming a work station, a sheave disposed rearwardly of the work station, means mounting said sheave onto said frame for rotation in a generally vertical plane, and about a substantially horizontal axis; and a tensioned holding line substantially disposed in said generally vertical plane, said holding line angling around said sheave, in contact therewith, and exerting an inwardly directed force on said sheave, serving to hold the staging into close proximity with the work surface, both during up and down travel of the staging and when it is at rest.

10. In combination, a portable staging suspended at one end of cable, the other end of which cable is secured to an overhead anchorage means, said cable supporting said staging for up and down travel relative to a work surface, said staging comprising a deck, frame means extending upwardly from said deck and forming a work station, a sheave disposed rearwardly of the work station, a holding line disposed in a generally vertical plane, and extending around said sheave, in contact with the rearward portion thereof, and then angling inwardly both above and below the sheave, and means mounting the sheave onto the frame means of the staging, for rotation substantially in the generally vertical plane, and including spring means normally biasing the sheave against the holding line, and serving to maintain the sheave in tensioning engagement with the holding line.

11. In combination with a generally convexly vertically curved wall, a cable suspended staging comprising a deck, a frame connected to said deck and extending upwardly therefrom, wheels disposed forwardly of said frame and in contact with the curved wall, means mounting said wheels onto the frame, a sheave disposed rearwardly of the frame, said sheave having a grooved periphery, means mounting said sheave onto said frame for rotation in a generally vertical plane, said means comprising a torsion bar having first and second ends, means securing the first end of the torsion bar to the frame, fork means having tines extending on opposite sides of the sheave, an axle extending through the tines and through the center of the sheave, and means rigidly connecting said fork means with said second end of the torsion bar spring; and a cable in tension vertically spanning the work surface, rearwardly of the sheave, and engaged in the peripheral groove of the sheave, with said cable bending around the sheave and extending above said sheave at an angle to its line of approach to the sheave from below.

12. In combination, a portable staging adapted for up and down travel relative to a vertically arcuate work surface of generally convex curvature, said staging comprising a deck, frame means extending upwardly from said deck and forming an operators work station, winch drum means rotatably mounted on said frame means, drive means on said staging for said winch drum means, a fairlead atfixed to said frame above said winch drum means; a suspension line extending upwardly from the winch drum means and through the fairlead and up to an overhead anchorage location; and means urging the staging into close proximity with the work surface during its up and down travel relative thereto, said latter means comprising sheave means mounted on said frame, and a holding line disposed in a substantially common, generally vertical plane with said suspension line, and extending both above and below said staging, said holding line angling around the rearward portion of the sheave means, in contact therewith, and exerting a force on the sheave means urging the staging towards the work surface, including during vertical travel of the staging.

13. In combination, a wall; first and second suspended staging units adapted for up and down travel relative to said wall, said second unit being disposed above the first unit, with each staging unit including a fairlead; a first suspension cable for supporting the first staging unit, a separate second suspension cable for supporting the second staging unit, with the first suspension cable extending upwardly from the first staging unit, through the fairlead of said first staging unit, then through the fairlead of the second staging unit, and then to an overhead anchorage means, to which it is secured, and with the second suspension cable extending upwardly from the second staging unit, through the fairlead of said second staging unit, and then to an overhead anchorage means to which it is secured; and means urging said first and second staging units into close proximity with the wall, said means comprising separate line engaging means on each of said first and second staging units, and a line in tension extending in a generally vertical plane and angling around each of said line engaging means, in contact therewith, and sloping inwardly towards the wall both above the line engaging means of the second staging unit and below the line engaging means of the first staging unit.

14. A suspended staging adapted for up and down travel relative to a vertical work surface of convex curvature, said staging including a deck, frame means extending upwardly from said deck and including front and upper frame members, wheel means fastened to and extending forwardly of said frame means towards the work sur- 10 face, said wheel means including a support pivotally mounted on said frame generally above the upper frame member, at least one wheel assembly mounted on said support, said wheel assembly including a wheel, a fork having a stem and a pair of offset tines extending out from the stem and disposed on opposite sides of the wheel, an axle extending through the tines and the wheel, mounting said wheel for rotation about an axis that is oifset from the longitudinal center of the stem, means mounting said stem onto said support for rotation about its longitudinal center, and means interconnecting between said upper frame member and said support for adjustably affixing the angular position of said support relative to the upper frame member and in that manner changing the angular relationship of the stem axis to the work surface.

References Cited by the Examiner UNITED STATES PATENTS Re. 22,762 6/ 1946 Crom -242-7 489,368 1/1893 Bruce 182-442 1,142,806 6/1915 Fenton 182-36 X 1,647,915 11/ 1927 Hoffmann 18247 1,822,786 9/1931 Ratio 182-214 X 2,543,348 2/ 1951 Briese.

2,689,890 9/1954 Green 182-142 2,829,582 4/ 1958 Abbott 18247 2,881,029 4/ 1959 Tollefsen 182-144 3,095,060 6/ 1963 Reinhardt 182142 20 HARRISON R. MOSELEY, Primary Examiner.

REINALDO P. MACHADO, Examiner.