Founding Ladder System

This invention is generally related to the field of scaffolding and more particularly relates to the scaffolding supports for use inside boilers.

Various types of boilers are used in different industries, such as steam boilers used for electrical power generation. The boilers may have large, enclosed, metal-lined tanks used for containing water or steam and generally include a converging pair of downwardly sloping lower boiler tank walls. In order to ensure the continued satisfactory performance of boilers, the tanks must be periodically maintained, repaired, and internally cleaned. As a part of the procedure for maintenance, repair or cleaning, it is necessary for workmen to enter inside the boiler tank and work on the inside walls of the boiler. Scaffolding systems having platforms arranged in vertical levels are placed inside a boiler being maintained or cleaned so that workmen are provided with suitable platforms to stand on while working on the inside walls of the boiler. The platforms also provide a location for the placement of tools used in the work performed inside the boiler.

One previous approach used to support scaffolding inside a boiler included scaffolding support bars which were temporarily welded directly onto the lower boiler sidewalls. Scaffolding was then erected inside the boiler with support provided by vertical posts which would rest on the support bars and thus would transfer the weight of the scaffolding directly to the lower boiler sidewalls through weldments. This prior approach was not entirely satisfactory in that the welding was time-consuming and the scaffolding support bars had to be precisely arranged on the lower boiler sidewalls in order to properly support the vertical posts. Also, the locations of the support bars had to be precisely measured and laid out so that the vertical posts of the scaffolding would be properly supported. In this prior approach, after the cleaning or maintenance was completed, the weldments would be broken and the scaffolding support bars would be removed from the boiler sidewalls. The breaking and removing of weldments could damage the boiler walls.

Many and various types of scaffolding systems may be used to support work platforms inside a boiler. One type of scaffolding system is shown by H. S. Evans in U.S. Pat. No. 3,245,188 which shows the use of prefabricated members which can be easily fitted together to provide scaffold structures having a variety of base plans of differing sizes and which are braced at all the joints. In particular, FIG. 11 of that patent shows an adjustable post which may be used in scaffold structures. Similarly, adjustable struts for use in a scaffolding structure are shown by T. I. Gostling in U.S. Pat. No. 3,366,361. The disclosures of the two above-mentioned patents are incorporated herein by reference.

This invention involves an assembly of structures for supporting scaffolding inside a boiler. A founding truss is provided for horizontally spanning between the boiler walls and for transferring forces from the scaffolding to the boiler walls. Sidewall supports are provided for mounting on each end of the founding truss and are designed to extend above and along the boiler walls in order to provide support points for scaffolding above the sidewall supports.

A significant feature of this invention is that the use of a founding truss and sidewall supports as described in this invention allows scaffolding to be conveniently and quickly placed inside a boiler and removed from inside the boiler.

Another important feature of this invention is that no weldments need be attached to the insides of the boiler walls, thus preventing damage to the boiler walls, saving time, and obviating the need for precise layout measurements to be made on the inside of the boiler each time that scaffolding is to be erected therein.

Another feature of this invention is that the structures described are capable of use with a variety of differently sized boilers having different internal configuration shapes.

A further feature of this invention is that the structures used are modular in nature so that a relatively few different types of structures need be manufactured and elaborate scaffolding supports can be assembled as collections of these modular structures. Thus, the logistics of manufacturing, stocking, and distributing the scaffolding support assembly described herein is simplified by the modular nature of the structures comprising the assembly.

Another feature of the instant invention is the fact that the founding truss used provides vertical support to the scaffolding system over the central region of the internal boiler cavity.

Another feature of this invention is that the assembly may be disassembled into separate structures and each of the structures comprising the overall scaffolding support assembly is sized so as to be capable of passing through a reletively small aperture, such as the access door to a boiler. That is, the founding truss and sidewall founding supports are each narrow, elongated structures. The specific method of interconnecting and mounting the structures disclosed in this invention is especially adapted so that the physical size for the structure components is limited. The size limitations are important so that the scaffolding support assembly can enjoy wide use among the various existing boilers.

FIG. 1 is a partly cut-away, side elevational view of a boiler, a scaffolding system mounted inside the boiler, and the scaffolding support assembly of this invention.

FIG. 2 is a partially cut-away, side elevational view of a portion of the boiler, scaffolding system, and scaffolding support assembly shown in FIG. 1.

FIG. 3 is a perspective view of a sidewall support.

FIG. 4 is a top, plan view of a post support bracket.

FIG. 5 is a top, plan view of a portion of a founding truss.

Referring first to FIG. 1, scaffolding support assembly 10 is a founding ladder system which fits inside boiler 12 and rests against lower boiler walls 14 and 16. Boiler 12 is a generally rectangular fire box lined with tubes (water walls) which carry water or steam and are shown in the drawings as walls 14 and 16. Water walls 14 and 16 are generally planar and slope downwardly to converge toward a central opening slot 17 in the bottom of boiler 12.

Scaffolding support assembly 10 functions to provide vertical support to a scaffolding system 18 assembled inside boiler 12. The function of scaffolding system 18 is to allow workmen to repair and clean the inside walls of boiler 12, while providing the workmen with a platform on which to stand or place their tools while working.

Scaffolding system 18 is a modular assembly of individual parts which are commercially available and which are linked and attached together in a known way to create a series of platforms 20, 22, and 24 which are horizontal surfaces spaced apart vertically to provide surfaces on which workmen may walk to stand when inside boiler 12. The platforms 20, 22, and 24 are supported by the vertical uprights 26, 28, 30, 32, and 34 which are parts of the system 18 spaced apart along the width of boiler 12 and which are elongated, segmented posts for transfering weight and forces from the platforms 20, 22, and 24 to the scaffolding support assembly 10.

In practice, scaffolding system 18 includes a plurality of vertical uprights spaced apart along the length of boiler 12 to be parallel to and aligned with uprights 26, 28, 30, 32, and 34. A plurality of scaffolding support assemblies identical in construction to assembly 10 are spaced apart along the length of boiler 12 to support the vertical uprights and scaffolding system 18. Thus scaffolding system 18 is a three-dimensional latticework including vertical uprights to support horizontal platforms.

The vertical uprights, of which uprights 28, 30, and 32 are typical, are separated horizontally by a plurality of horizontal links, of which links 36 and 38 are typical, which are connected between pairs of the uprights and which extend across the width and along the length of boiler 12.

Support assembly 10 has founding truss 40 which is shaped like a steel "I" beam extending horizontally between the lower boiler sidewalls 14 and 16. The founding truss 40 is an elongated beam having a left end 42 and a right end 44, having sidewall supports 46 and 48, respectively, mounted thereon. The sidewall supports 46 and 48 are wedged in place resting against the sidewalls 14 and 16, respectively.

As shown in the embodiment of FIG. 1, the sidewall supports 46 and 48 are plates securely attached to founding truss 40. The sidewall supports 46 and 48 are mounted at appropriate angles to the truss 40 so that the truss 40 wedges between the sidewalls 14 and 16, the supports 46 and 48 conform closely to the shape of the sidewalls 14 and 16, respectively, and the truss 40 is maintained in a substantially horizontal position inside the boiler 12. The purpose of the supports 46 and 48 is to transfer forces from the scaffolding system 18 which pass through the founding truss 40 and to the sidewalls 14 and 16.

The supports 46 and 48 are preferably steel plates which are securely welded to the truss 40 which also is preferably composed of steel. The supports 46 and 48 may also have plywood facing pads (see FIG. 2) for contacting the sidewalls 14 and 16, respectively. The purpose of placing plywood facing pads on the supports 46 and 48 is to provide secure gripping of the sidewalls by the supports, to allow the supports to conform to any surface imperfections in the sidewalls, and to provide for shock absorption between the supports and the sidewalls.

The founding supports 50 and 52 extend upwards from the truss 40 along the sidewalls 14 and 16, respectively. The founding supports 50 and 52 are substantially identical in construction and preferably each consists of a ladder having a pair of tubular uprights connected by a plurality of spaced-apart rungs. The purpose of the founding supports 50 and 52 is to provide support for vertical posts extending downwards from the scaffolding system 18.

The founding brackets 54 and 56 are placed on the founding support 50 and are substantially identical in construction. The founding brackets 58 and 60 are placed on the founding support 52 and are substantially identical in construction to the founding brackets 54 and 56. The function of the founding brackets 54, 56, 58, and 60 is to provide adjustable points of support for the scaffolding system 18 on the founding supports 50 and 52. For example, the founding bracket 54 adjusts laterally in length along the founding support 50 in order to provide support for the vertical post 26 of the scaffolding system 18. The vertical post 26 is similar in construction to the vertical posts 28, 32, and 34, and includes an adjustable section 62, the length of which is vertically adjustable in order to level the scaffolding system 18 and in order to properly contact the founding bracket 54. Therefore, the founding bracket 54 is slidably adjustable along the length of the founding support 50 in order to reach a proper horizontal position to meet with the post 26. The post 26 is vertically adjustable (by means of section 62) in order to properly meet with the founding bracket 54. The function of the founding bracket 54 is to provide vertical support for the post 26 and to transfer forces from the post 26 to the founding support 50. The forces transferred through the founding bracket 54 are transferred to the sidewall 14 through the founding support 50 and the founding truss 40. The post 30 similarly includes an adjustable section which rests on the truss 40 in order to adjust the vertical position of the scaffolding system 18.

An accessway door 64 is provided in the side of the boiler 12 in order to allow workmen and their equipment to move inside the boiler 12. The access doorway 64 is normally made of a very small size because of the high temperatures and pressures which must be contained inside the boiler 12. The accessway 64 is normally of a size just large enough to comfortably allow a workman to enter into and leave from the inside of the boiler 12. Since the size of the accessway 64 is limited, it is necessary that each of the parts of the scaffolding assembly 18 and the scaffolding support assembly 10 be small enough to fit easily through the accessway 64 each time that cleaning or repair operations are to be performed inside the boiler 12. Therefore, the scaffolding assembly 18 is of modular construction which may be assembled and disassembled inside the boiler 12. Similarly, the scaffolding support assembly 10 of this invention is of a modular construction which may be disassembled and assembled inside the boiler 12. The founding supports 50 and 52 may be coupled and uncoupled from the founding truss 40 so that the founding truss 40, and the supports 50 and 52 may be easily passed through the accessway 64. The founding supports 50 and 52 are preferably each assembled as lengths of ladder coupled together so that the length of the scaffold supports 50 and 52 may each be adjusted to accommodate the particular boiler 12 used and to allow each of the scaffolding supports 50 and 52 to be disassembled into shortened lengths when passing through the accessway 64. The founding brackets 54, 56, 58, and 60 may be removed from the founding supports 50 and 52 when transfer through the accessway 64 is required. The modular nature of the founding support system 10 is an advantage not only in allowing easy passage through the accessway 64 of the boiler 12, but also is an advantage in that the system 10 may be expanded to fit various different size boilers by including the particular length of founding supports 50 and 52 required, and the particular numbers of founding brackets required. The modular nature of the founding support system 10 also allows the commercial supplier of scaffolding products to stock a limited variety of component parts which may be assembled into the many various arrangements required by users.

In practice, workmen will pass the founding truss 40 through the accessway 64 first in order to form a brace for the scaffolding system 18. The workmen will then pass through the accessway 64 the components required to construct the scaffold supports 50 and 52 and then will attach those components together and connect the scaffold supports 50 and 52 to the founding truss 40. Since a plurality of founding trusses identical to the truss 40 will normally be arranged in a parallel sequence along the length of the boiler 12, the workmen will construct a founding support system 10 consisting of a large number of founding trusses, founding supports, and founding brackets before beginning the construction of the scaffolding system 18 inside the boiler 12.

After the maintenance or cleaning operation has been completed inside the boiler 12, the workmen will disassemble the scaffolding system 18 and pass its component parts through the accessway 64. After the scaffolding system 18 has been removed, the component parts of the scaffolding support system 10 will be disassembled inside the boiler 12 and removed through the accessway 64.

Referring next to FIG. 2, the support 46 includes a flat steel plate 66 welded to the "I" beam truss 40. The pad 68 is securely attached to the plate 66 and preferably is a sheet of plywood. The pad 68 is positioned between the plate 66 and the boiler sidewall 14. The plate 66 is positioned on the truss 40 so that the pad 68 makes intimate contact with the boiler sidewall 14. The function of the pad 68 is to conform to any irregularities in the sidewall 14 and to remain in place on the boiler sidewall 14 by friction contact with the sidewall 14.

As an alternative embodiment (not shown in the drawings), the sidewall supports 46 and 48 may be rotatably mounted or pivotably on the truss 40 so that the support plates 46 and 48 are allowed to automatically conform to the slope of the lower boiler walls 14 and 16. Such a construction is of particular advantage to minimize the different types of trusses required for the various boilers in use. If the plates 46 and 48 are not allowed to automatically conform to the shape of the sidewalls 14 and 16, then the truss 40 may only be used with boilers having sidewalls at angles exactly matching those of the plates 46 and 48. The alternative embodiment of pivotably mounting the support plates 46 and 48 on the truss 40 allows the truss 40 to be used with various boilers having various differing sidewall angles. The support plates 46 and 48 may be pivotably connected to the truss 40 by a hinge construction in which hinge plates are welded to project from each of the support plates 46 and 48, and in which hinge pins project horizontally through the hinge plates and the truss 40 so that the support plates 46 and 48 may pivot vertically on the ends 42 and 44 of the truss 40.

A mounting hinge 70 is mounted on the upper surface of the end 42 of the truss 40. The function of the hinge 70 is to pivotably connect the founding support 50 to the truss 40. The hinge 70 includes an elongated hinge rod 72 having stub connectors 74 and 76 projecting therefrom (with connector 76 shown behind connector 74 in FIG. 2). The function of the rod 72 is to rotate inside the hinge 70 to provide the hingeing action. The function of the connectors 74 and 76 is to fit inside the hollow tubular uprights 78 and 80, respectively (with upright 80 shown behind upright 78 in FIG. 2). In use, the connectors 74 and 76 may be inserted into, or pulled out of, the hollow uprights 78 and 80 so that the founding support 50 may be connected to or disconnected from the truss 40.

A function of the hinge 70 is to hold the founding support 50 in place so that the founding support 50 may pivot to conform to the angle of the boiler sidewall 14, and to prevent the founding support 50 from moving downwards along the sidewall 14 or from sliding across the length of the truss 40. The hinge 70 also provides for a transfer of forces between the founding support 50 and the truss 40 so that the scaffolding system 18 is supported.

The strap retainers 82 and 84 are part of the hinge 70 and encircle the hinge rod 72. The function of the strap retainers 82 and 84 is to hold the hinge 70 together and prevent the hinge rod 72 from sliding out of the hinge 70. The hinge 70 is preferably constructed as a steel angle iron having the hinge rod 72 mounted inside the angle with the strap retainers 82 and 84 welded in place over the mouth of the angle iron in order to trap the rod 72.

The founding bracket 54 includes rung gripping hooks 86 and 88 which fit over and engage the rungs 90 and 92 of the founding support 50. In the ladder-like construction of the founding support 50, the rungs 90 and 92 extend between the uprights 78 and 80. The function of the hooks 86 and 88 is to transfer forces between the founding bracket 54 and the founding support 50 and also to hold the founding bracket 54 in place on the founding support 50.

The founding bracket 54 preferably includes a threaded tubular body 94 having an extensible section 96 passing through the center thereof. A threaded collar 98 is mounted around and threaded on the tubular section 94 and serves to adjust the amount of extension of the section 96 by adjusting the position of a pin 100 which passes through a slot in the section 94 and a hole in the section 96. In practice, the degree of extension of the section 96 is adjusted by placing the pin 100 in a desired hole in the section 96 and by rotating the collar 98 to adjust the position of the pin 100 relative to the section 94.

The post receiving channel 102 is preferably constructed of a steel angle iron securely attached to the upper end of the extensible section 96. The function of the post receiving channel 102 is to provide a support point for the vertical upright post 26 of the scaffolding system 18. In use, the pin 100 and collar 98 are adjusted so that the channel 102 is positioned directly vertically underneath the post 26. If sufficient adjustment is not available through the use of the pin 100 and collar 98, the founding bracket 54 may be repositioned so that the hook 86 engages the rung 94 of the founding support 50 and so that the hook 88 engages the rung 90. Thus the position of the channel 102 along the length of the founding support 50 may be adjusted by changing the position of the hooks 86 and 88, and by adjusting the pin 100 and collar 98.

The adjustable section 62 of the post 26 may be adjusted in cooperation with the adjustments made to the founding bracket 54 so that the post 26 properly fits into the channel 102.

Referring next to FIG. 3, the ladder-like construction of the founding support 50 is shown. The founding support 50 preferably is constructed from a plurality of sections identical to the section 104 shown in which the sections are held together by pins 106 and 108 which fit inside the hollow uprights 78 and 80. It is preferable that the founding support 50 break down (disassemble) into sections identical to section 96 in order that the founding support 50 may easily pass through the accessway 64 of the boiler 12. The use of ladder sections identical to section 104 allows founding supports of various lengths to be built up in order to accommodate various boiler sizes and configurations.

Referring next to FIG. 4, the tubular body member 94 and the extensible section member 96 together form a strut which is parallel to a substantially identical strut 110 which is also connected to the channel or through 102. The strut 110 also clips over the parallel, spaced-apart support rungs 90 and 92 of the founding support 50 so that the strut 110 also holds the channel 102 in place. In use, the length of the strut 110 is adjusted in the same way as adjustments to the pin 100 and collar 98, so that the channel 102 remains substantially horizontal. The strut 110 cooperates with the strut formed by the body 94 and the section 96 to support a scaffolding post resting in the channel 102.

Referring next to FIG. 5, the retainer straps 82 and 84 are preferably positioned between the rod or stub connectors 74 and 76 so that the hinge rod 72 is trapped inside the hinge 70 and is prevented from falling away from the truss 40.