US3863877A - Traction head for a column-mounted shoring bracket - Google Patents

Abstract

A traction head adapted for use at the upper end of a columnmounted shoring bracket of the type which maintains a concrete slab-supporting formwork in an elevated position during concrete pouring operations, lowers the formwork after the concrete has become set, and permits formwork removal by a rolling operation to withdraw the formwork from beneath the concrete slab to the end that it may be used somewhere else in the concrete building undergoing erection. Two traction rollers on which the associated stringer of the formwork rides during its withdrawal from a use position are provided with end flanges for guiding the stringer during its tractional withdrawal and the rollers are reversible in end-to-end fashion to accommodate different types of stringers.

Description

[ Feb.4, 1975 ited States atet [19] Gregory ,776,499 12/1973 Turner 249/219 R X TRACTION HEAD FOR A COLUMN-MOUNTED SHORING BRACKET Inventor:

Primary Examiner-J. Franklin Foss ['75] Kirk Gregory Bamngton Attorney, Agent, or FirmNorman H. Gerlach [73] Assignee: Symons Corporation, Des Plaines,

Ill.

[57] ABSTRACT A traction head adapted for use at the upper end of a column [22] Filed: June 1, 1973 [21] Appl. No.: 365,957

-mounted shoring bracket of the type which maintains a concrete slab-supporting formwork in an elevated position during concrete pouring operations, 10

wers the formwork after the concrete has become set, and permits formwork removal by a rolling operation to withdraw the formwork from beneath the concrete slab to the end that it may be used somewhere else in the concrete building undergoing erection. Two traction rollers on which the associated stringer of the References Cited formwork rides during its withdrawal from a use posi- UNITED STATES PATENTS tion are provided with end flanges for guiding the 8/1928 Gottwald.

mm ea d m0 m hm t w mm s a N am We NH ll mm F 2.. mm .m .M w Id 3 an m m; um m 5 mm" m s-m 8 fl .m C m k a 2 HbW i dm r m e e ger. n mm Mad 3,155,051 11/1964 Sherburne 3,407,011 10/1968 Zeidler..... 3,504,879 4/1970 Strickland 3,771,753 11/1973 Wilbur.....

TRACTION HEAD FOR A COLUMN-MOUNTED SHORING BRACKET The present invention relates gennerally to a columnmounted shoring bracket for supporting concrete slab formwork during concrete pouring operations as well as during lowering of the formwork away from the completed slab and also during lateral withdrawal of the lowered formwork from beneath the slab for purposes of reuse. More specifically, the invention is concerned with a novel traction head which is designed for use in connection with a shoring bracket of the aforementioned type, the head affording tractional means in the form of a pair of rollers which serves to guide the formwork from beneath the slab after the formwork has been lowered so that it may be removed from the concrete building or other installation undergoing erection.

Present day column-mounted shoring brackets which are designed for the same general purpose as that of the present invention are of three general types, the distinction being based upon the manner in which they function. In one type, as disclosed in U.S. Pat. No. 3,504,879, granted on Apr. 7, 1970 and entitled Column Shore Bracket, the formwork is supported during concrete pouring operations upon a supporting head at the upper end of avertically shiftable carriage part and is incapable of lateral shifting movements by reason of its frictional engagement with the supporting head upon which it rests. After the concrete of the slab has set or hardened, the carriage part of the bracket is lowered and the formwork that is supported by the aforementioned head is deposited upon a roller so that after the supporting head has moved below the level of the then roller-supported formwork, the latter may" be shifted laterally on the roller and thus withdrawn from beneath the slab. In another type of shoring bracket, as illustrated and described in copending patent application Ser. No. 366,470, filed on June 4, 1973 and entitled Column-mounted Shoring Bracket Assembly for Overhead F ormwork," the formwork is supported during concrete pouring operations upon a roller which is carried at the upper end of a jack screw. In such a shoring bracket when the jack screw is turned so as to shift it downwards after concrete slab formation, the roller serves to lower the formwork to a position where there is sufficient clearance between it and the slab to permit lateral shifting of the formwork from beneath the slab. in a third type of shoring bracket, as illustrated in copending patent application Ser. No. 366,434, filed on June 4, I973 and entitled Column-Mounted Shoring Bracket Assembly For Overhead Formwork, the formwork is supported during concrete pouring operations upon a roller arrangement which is carried directly upon a vertically shiftable carriage, the raising and lowering movements of which are effected under the control of a jack screw. Upon operation of the jack screw after the concrete of the slab has become set, the carriage is lowered and the consequent downward movement of the roller arrangement serves to lower the formwork until it is clear of obstruction, after which the formwork is capable of being shifted laterally on the roller arrangement for formwork withdrawal purposes. In the first type, the formwork is supported on the roller only during lateral formwork withdrawal operations. In the two other types, the formwork is at all times supported on the roller arrangement. The traction head of the present invention is capable of use with all three types of shoring brackets such as have briefly been outlined above.

In order to insure uniform linear travel of one of the horizontal stringers of a concrete slab-supporting formwork across the surface of a supporting roller at the time the formwork is being withdrawn from beneath a slab, it has been proposed that, in addition to the traction roller or rollers on which the stringer travels, a separate edge guide roller be positioned alongside such traction roller to prevent the stringer from running over the side edge of such roller. However, due to the varying widths of the various types of structural stringers which are employed in the building industry, special roller assemblies must be constructed to accommodate these widths. Ordinary l-beam type stringers have comparatively narrow bases so that if edge guide rollers are to be employed, they may be positioned fairly close to the traction roller or rollers. Split lbeams which consist of spaced apart channels present a wider spread at their base and, in such instances, the edge guide rollers must be positioned further away from the median plane of the traction roller or rollers, in which case it is desirable to employ a wider traction roller. This necessitates reconstructing the roller supporting head each time a different type of stringer is encountered.

The present invention affords a novel form of traction head which is adapted for association with and to form a part of a column-mounted shoring bracket and isso designed that it will accommodate a wide variety of formwork stringers while at the same time affording adequate edge guide means for preventing the associated stringer from becoming dislodged from the traction surface of the roller arrangement, this being the case regardless of whether the spread of the stringer base is wide or narrow, and whether the base presents an underneath surface which is uninterruptedly planar across its width so that it makes full line contact with the combined supporting and traction roller arrangement on which it travels, or whether the stringer is provided with a divided base structure. The provision of such a traction head, and particularly one which is capable of serving its purpose regardless of whether it be mounted on the upper end of a jack screw which functions to support the load or on the upper end of a vertically shiftable carriage, constitutes the principal object of the present invention.

Briefly, in carrying out this object, the invention contemplates the provision in a traction head for a columnsupported shoring bracket of a novel composite roller assembly including a pair of coaxial roller units and a supporting roller cage, each roller unit being in the form of a half-spool in that it has a cylindrical traction sectionand a frustoconical end flange section which functions as an edge guide for the stringer which is supported by and travels on the traction head. The roller units are individually reversible in end-to-end fashion so that when the end flange sections assume positions remote from each other the distance between them is sufficient to accommodate the relatively wide spread of a i s; of h our im whishisn yi s yv a uninterrupted planar bottom surface. In such an in stance the underneath surface of the stringer rides on the traction sections of the roller units while the end flange sections straddle the base of the stringer and functions as edge guides therefor. When the roller units are reversed in the cage which supports them, the two end flange sections assume positions of close proximity to each other in order to accommodate a split stringer. In such an instance, the spaced apart stringer halves ride upon the two cylindrical traction sections of the roller units while the two end flange sections project radially outwardly and into the void which exists between the two stringer sections, thus serving as a center-guide for the stringer. The roller cage of the present traction head is provided with facilities whereby it may be swivelly applied to the vertical load bearing member or carriage of a wide variety of shoring brackets, regardless of whether such brackets utilize jack screws for actual load supporting purposes or vertically shiftable loadbearing carriages.

Other objects and advantages of the present invention, not heretofore mentioned, will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by the claims at the conclusion hereof.

in the accompanying single sheet of drawings forming a part of this specification, one illustrative embodiment of the invention is shown. 3

In these drawings:

FIG. 1 is a perspective view of a column-mounted shoring bracket embodying a traction head embodying the present invention;

FIG. 2 is a side elevational view, partly in section, of the traction head, showing the roller units which are associated therewith positioned to accommodate a stringer of the l-beam type; and

FIG. 3 is a side elevational view similar to FIG. 2 but showing the roller units reversely positioned in order to accommodate a split stringer.

Referring now to the drawings in detail and in particular to FIG. 1, a shoring bracket which includes a traction head 11 embodying the present invention is shown in its operatively mounted position against one side face of a concrete building column 12. The latter may be assumed to be associated with a multi-story concrete building undergoing erection. The function of the bracket 10, in combination with identical brackets which are applied to other columns of thebuilding, is to support a formwork for a concrete slab during the time that the wet concrete is being poured and thereafter, while the concrete hardens, after which manipulation of the bracket serves to lower the formwork away from the slab until sufficient clearance is established to permit lateral removal of the formwork from beneath the slab for purposes of reuse. The particular shoring bracket 10 which has been selected for environmental illustration of the present traction head forms no part of the present invention since the traction head 11 is capable of being used in connection with a wide variety of other forms of shoring brackets.

The shoring bracket 10 is of the general type which is shown and described in aforementioned copending application Ser. No. 366,470, and no claim is made herein to any novelty associated therewith except insofar as the nature of the traction head 11 is concerned. For a more complete understanding of the nature and function of the shoring bracket 10 than will be set forth herein, reference may be had to such copending application which, by reference thereto, is hereby incorporated in and made a part of the present patent application, insofar as it is consistent with the present disclosure.

Briefly, the shoring bracket It) involves in its general organization two component parts, namely, a fixed column-attached shelf part 14 and a removable jack part 16. The shelf part 14 is of unitary construction, while the jack part 16 is of a composite nature in that it is in the form of an assembly of functional component parts.

The fixed shelf part 14 of the shoring bracket 10 is formed of flat plate stock and includes a rectangular, vertically extending backing plate 18, a pair of forwardly projecting, horizontally extending shelf arms 20, and a pair of triangular, vertically extending gussetlike side plates 21.

These various parts are suitably welded together in order to produce a unitary whole. Two vertically spaced bolt holes 22 are formed in the backing plate 18 for reception therethrough of the shank portions of respective bolts (not shown) by means of which the shelf part 14 as a whole may be fixedly secured to the column 12.

The jack part 16 of the shoring bracket 10 is comprised of a horizontally extending base plate 23 having parallel side edges from which there depend a pair of opposed channel-forming flanges 24. A trapezoidal nose portion 26 projects forwardly from the main body of the base plate 23 and overhangs in fascia fashion the channel-forming flanges 24. A pair of holes 28 is provided in the base plate 23 and these register with additional holes 30 in the shelf arm 20, the various holes being provided for the purpose of receiving therethrough a pair of fast pins (not shown) by means of which the parts 14 and 16 may be removably secured together.

An upstanding internally threaded boss 32 projects upwardly from the central region of the base plate 23 and threadedly receives therein ana elongated vertically disposed jack screw 34, the lower end of the jack screw being provided with a torque nut 36 whereby the jack screw may be turned by a wrench or similar turning tool in connection with vertical adjustment thereof.

The jack screw 34- is of tubular construction and the upper end thereof has swivelled thereto the novel traction head 11 of the present invention. As will be made clear presently, this traction head has associated therewith a pair of traction rollers upon which the slabforming formwork is adapted to travel and, in order to prevent the traction head from rotating bodily with the jack screw 34, an outrigger-type, vertically extending, anti-torque slide member 40 is secured at its upper end to the head 11, projects downwardly therefrom and passes through a guide slot 42 which is formed in the trapezoidal nose portion 26 of the base plate 23. A fast pin 44 which is removably received in an opening in the lower end of the anti-torque slide member 40 captures the slide member in the slot 42 and prevents upward separation of theslide member from said base plate 23.

Assembly of the jack part 16 on the fixed shelf part 14 is accomplished by sliding the channel-forming side flanges 24 of the base plate 23 of the jack 16 of the shoring bracket 10 over the outer edges of the two shelf arms 20 of the fixed shelf part 14, and thereafter insert ing aforementioned fast pins in the registering holes 28 and 30.

The traction head 1] involves in its general organization a roller-supporting frame 50 embodying a flat bot tom plate 52 from which there projects upwardly a pair of outer side plates 54 and 56, and a medial plate 58, the three plates serving to support a horizontal roller shaft 60 on which there is mounted a pair of rollers 62 and 64. The two rollers are identical in construction, each roller being of half-spool design and including a cylindrical traction section 66 and a frustoconical end section or spool flange 68. The roller 62 is straddled by the plates 54 and 58, while the roller 64 is straddled by the plates 56 and 58. Cotter pins 70 extend through transverse holes in the exposed end extremities of the shaft and serve releasably to capture the shafts 60 with respect to the frame 50.

The swivel connection between the frame 50 and the jack screw 34 is established by means of a vertically extending pilot pin 72 which is secured centrally to the bottom plate 52 of the frame 50 and projects downwardly into the upper end of the jack screw 34.

The half- spool rollers 62 and 64 are intended to be reversed in end-to-end fashion on the shaft 60 in order to accommodate tractional support for stringers which are provided with different bases. In FIG. 2 of the drawings the rollers 62 and 64 are shown as being disposed on the shaft 60 in such a manner that they will support an l-beam type of stringer such as is indicated in dotted lines and designated by the reference numeral 74. Accordingly, the rollers 62 and 64 are disposed on the shaft 60 so that their frustoconical end sections or spool flanges 68 assume remote positions in close proximity to the plates 54 and 56 while the cylindrical sections 66 thereof assume positions close to the medial plate 58. ln this position of the rollers 62 and 64, the end sections or flanges 68 thereof serve as edge guides which straddle the base of the l-beam stringer 72.

Where the present traction head 11 is employed for tractionally supporting a split stringer such as the stringer 75 of FIG. 3, which as shown in the drawings is comprised of two channels 76 which are maintained in spaced apart relationship by means of a medial web 78, the rollers 62 and 64 are so disposed on the shaft 60 that the end sections or flanges 68 are in close proximity to the medial plate 58, while the cylindrical sections 66 of the rollers are remote from each other and in close proximity to the plates 54 and 56. When the rollers are thus positioned on the shaft 60, the end sections or flanges 68 project radially into the void which exists between the channels 76 of the stringer 75 and thus serve as a composite center guide for the stringer.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. Therefore, only insofar as the invention is particularly pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. A traction head designed for the rolling support of a horizontal stringer that is associated with a formwork for concrete, said head comprising a rolled-supporting frame having a swivel connection whereby it may be secured to a shoring support for the stringer, said frame comprising a bottom plate, a pair of upstanding end plates, and a central upstanding plate disposed midway between the end plates, said plates being of substantially equal height and provided with aligned holes therethrough, a horizontal shaft projecting through said holes above the level of said bottom plate and having its opposite ends and medial region removably supported by said plates, a pair of stringer-supporting rollers rotatably mounted on said shaft on opposite sides of said central plate, each roller substantially spanning the distance between said central plate and the adjacent side plate, each of said rollers being of half-spool design and including a cylindrical section and a single radially extending flange, the upper end of said central plate terminating below the level of the uppermost portion of the cylindrical section of each roller, said rollers being reversible in end-to-end fashion on the shaft whereby, when they are positioned thereon so that the end flanges are remote from each other, the cylindrical sections are adapted to make tangential rolling contact with.thqhass fas als lrbsim XPEE BLWDi Q th end flanges function as edge guides which straddle said base, and when they are positioned on the shaft so that the end flanges are in close proximity to each other, the cylindrical sections are adapted to make tangential rolling contact with the spaced apart base sections of a split, channel-formed stringer while the end flanges project between said base sections and constitute a center guide therefor, and removable means on at least one end of said shaft disposed exteriorly of the adjacent end plate and adapted to retain said shaft in position on said plates against endwise removal from said aligned holes.

2. A traction head as set forth in claim 1 and wherein said end flanges of the rollers are frusto-conical and have their small bases facing the adjacent cylindrical sections.

Claims (2)

1. A traction head designed for the rolling support of a horizontal stringer that is associated with a formwork for concrete, said head comprising a rolled-supporting frame having a swivel connection whereby it may be secured to a shoring support for the stringer, said frame comprising a bottom plate, a pair of upstanding end plates, and a central upstanding plate disposed midway between the end plates, said plates being of substantially equal height and provided with aligned holes therethrough, a horizontal shaft projecting through said holes above the level of said bottom plate and having its opposite ends and medial region removably supported by said plates, a pair of stringer-supporting rollers rotatably mounted on said shaft on opposite sides of said central plate, each roller substantially spanning the distance between said central plate and the adjacent side plate, each of said rollers being of half-spool design and including a cylindrical section and a single radially extending flange, the upper end of said central plate terminating below the level of the uppermost portion of the cylindrical section of each roller, said rollers being reversible in end-to-end fashion on the shaft whereby, when they are positioned thereon so that the end flanges are remote from each other, the cylindrical sections are adapted to make tangential rolling contact with the base of a single Ibeam type stringer while the end flanges function as edge guides which straddle said base, and when they are positioned on the shaft so that the end flanges are in close proximity to each other, the cylindrical sections are adapted to make tangential rolling contact with the spaced aparT base sections of a split, channel-formed stringer while the end flanges project between said base sections and constitute a center guide therefor, and removable means on at least one end of said shaft disposed exteriorly of the adjacent end plate and adapted to retain said shaft in position on said plates against endwise removal from said aligned holes.

2. A traction head as set forth in claim 1 and wherein said end flanges of the rollers are frusto-conical and have their small bases facing the adjacent cylindrical sections.

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