US2808296A - Scaffold plank - Google Patents

Description

Oct. 1,1957 T. G. s'rlNsoN scAFFoLD PLANK Original Filed April 21, 1951 Qiznventor F l 6 5 Trgman'e. sfingbn soAFroLn PLANK Continuation of abandoned application Serial No. 222,189,

April 21, 1951. This application November 9, 1956, Serial No. 621,474

6 Claims; (Cl. 304-38) This invention relates to scatfolds and more particularly to a plank forming a part of a scatfold. This application is a `continuation of my appli-cation, Ser. No. 222,189, iiled April 2l, 1951, for Scaiold Plank, now abandoned.

One object of the invention is to provide a scaffold plank formed of upper and lower sheets of plywood which are held in proper spaced rela-tion to each other 'by longitudinally extending light metal rai-ls, channel shaped and tapering to effectively secure the boards bowed longitudinally so that they are spaced from each other at a point midway the length of the plank and converge toward the ends of the plank.

Another object of the invention lies in the provision of a scaffold plank which -is very light for ease in handling and yet very strong and not liable to sag between supports upon which its ends rest when in use.

Another object of the invention lies in .the provision of a scatold plank having sectional metal channels which butt in end to end relation and lare secured by a metal splicing member at the adjoining ends thus greatly reducing the expense of manufacture :and also enhancing the simplicity and ease of construction.

Another object of the invention lies in the provision of a .scalold plank comprising two thin sheets of light weight iibrous material, such as plywood forming opposed surfaces, both of which have unobstructed outer surfaces to be walked upon, `the sheets being separated lby longitudinally extending rails Vcomprising light weight channels having webs tapering from a max'imum width midway between the ends of lche sheets to a minimum width .at the ends of the sheets, the channels having flanges through which rivets may be passed lto secure the plywood sheets to the rails.

Another object of the invention lies in the provision of 'a scaffold plank so constructed that when supported it may have either face disposed upwardly.

Another object of the invention l'ies in the lprovision of a scatold plank which is simple in construction, very strong, light, and not liable to become damaged .by rough usage.

AIn the accompanying drawings, forming a part of this specification and in which like numerals lare employed to designate like parts,

Figure 1 is a side elevation of a scaffold which includes my improved plank supported on spaced supports;

Figure 2 is a view of the improved .scaffold plank in perspective;

Figure 3 is a fragmentary perspective view of one joint of the longitudinally extending rails;l

Figure 4 is a fragmentary cross section of an end portion of the plank as at line 4-4 of -Figure 2; andl -Figure 5 is a transverse cross section taken through the improved scaffold plank.

Referring now more particularly to the drawing, I have shown spaced step-ladder type .supports 6-6 which have the usual spaced side bars 7 with multiple horizontally disposed steps secured therebetween and a downwardly States Patent M' 2,808,296 Patented Oct. 1, 1957 ICC spreading rear leg 8 pivotally secured at the top end of the side bars 7. The rear leg 8 is secured against further spreading by a suitable brace or strap 9.

-My improved plank, indicated in general lby the numeral 10, is positioned with each end resting upon a selected step of the spaced supports 6 to dispose the plank in horizontal supported position and thus allow Workmen to work therefrom.

rIlhe plank is constructed with longitudinally extending channel sections 11 formed preferably of light weight metal, `but it will be understood that other suitable materia'ls may tbe .used which will effectively serve to form a strong, light weight sc'aold plank. Each channel section 11 is provided with :a tapered web 12 and llanges 13 which extend in the same direction from the web 12. When viewed in side elevation, it will be seen that each channel has a tapering configuration from its ,butt end 14, midway the length of the scatold plank, to its outer or -tip end 15. It can be plainly seen that the plank 10 lis thus constructed to provide the greatest tensile strength in the scaffold plank at the point the greatest distance from the supports 6.

Two tapered channels 11 are secured together to form each rail 16 with the butt ends 14 `in end to end relation, and the complete plank uses three ra'i-ls, a central rail and two side rails.

The joints of the cooperatin-g channels are reinforced by splicing members 19 which are also channel shaped in transverse cross section and have ilanges 20 formed at right angles to the body. When viewed in side elevation, the splicing mernbers each are formed with tapered webs so that the ilanges Z0 converge toward each other in the direction of the ends, and this provides a central upper and lower ridge 21. The splicing members :are of a size .adapting them to lit snugly in nested position within the flanges of the channels 11 where .they join each other with the butt ends in end to end relation. Aligned holes 22 are drilled through the flanges 13 and 20 and rivets secure the splicing members 19 in place.

The center rail 16 is cut slightly shorter than the two side rails 16 to provide space for securing the'channelshaped end fillet 23 between the ends of the spaced side rai-ls kand :across the end of the central rail. The lillet 23 strengthens the plank .against 'twisting movement 'as well as to close the open end between the upper `and lower sheets of plywood 17.

The skin Ior sheet 17 is applied to the top and bottom ilanges 13 of the rails 16 and is secured thereto Iby rivets 18 which pass through 'the flanges 13 and the sheets 17 and the rivets are secured as in the usual manner with a flat head 18 being ilush with the surface of the sheets 17. Plywood sheets have been shown in the drawings, but metal or composition materials would .be effective for this purpose also.

Since the planks are of comparatively great length, it is necessary that the sheets be formed of multip'le sections, iand Iwhere one sheet or portion of sheet joins another portion of the sheet, the two edges are provided with cooperating bevelled edges, and secured 'by a strong adhesive.

The tapering contiguration of the plank towards its ends vcause the downward pressure to exert end to end pull on the lower sheet 17 and end to end compression on the upper sheet 17 thus relieving the bending pressure applied to the rails. This permits the rails t-o be formed of metal of thinner gauge, and in this way reduces the weight of the plank as well as the cost of manufacture.

The structure provides a light Weight manually movable scaffold plank in which the longitudinally extending rails are thickened midway their lengths and taper toward each end. The word thickened as used herein means increased in distance or height from one tread sheet engaging face of the rail to the face Vof the rail enf gaging the other tread sheet. This structure causes the tread sheets to diverge from each other from their ends inwardly when the sheets are secured toV the railswas described hereinbefore.

The outer .channel shaped rails and the channel shaped end fillets 23 are positioned with their flanges vfacing outward so that it is easy to grasp the edgeV of the plank at the sides or ends for handling. The r'ails and .lle'ts provide spacing Ibetween the sheets 17 throughout said rails being thickened midway their leugths'and taper- Y ing toward each end, and spaced upper and lower elongated tread sheets one above the other securedV to said rails, whereby the sheets are spaced from each other at their ends and diverge from each other yfrom the ends inwardly.

2. A light weight manually movable scatold plank comprising spaced upper and lower elongated tread sheets `one above the other and bowed away from each other from the ends toward a point midway the length of the plank, tapering channels each having a relatively wide web :at the middle of the plank and a narrow web at an end of the plank, pairs of said channels forming side rails and inner rails when positioned with the butt ends in end to end relation, splicing members channelshaped in cross section and having anges, each said splicing member having central transverse ridges on its anges, said flanges converging toward the ends of said splicing member, said spli-cing member adapted to nest in said rails at -the joint of the butt ends, rivets extending through aligned openings in said splicing members and cooperating pairs of channels rigidly securing said pairs of channe'ls to form said rails, said upper and lower sheets riveted to the multiple rails, and channel-shaped lillets for closing the open ends of the plank.

3. A light weight manually movable scaffold plank comprising spaced upper and lower elongated tread sheets one above the other and bowed away fnom each other progressively from the ends inwardly, tapering channels each having a relatively wide lweb at the middle of the plank and a narrow web at an end of the plank, pairs i of said channels secured with the butt ends in end to end relation and forming side rails and a central rail, said central rail being slightly shorter than said side rails, anges on said rails, rivets securing said upper and lower sheets :to said flanges, means for securing said butt ends together, and fillets secured between companion ends of said Side rails and across the ends of said :center rail to close the ends of the planks.

4. A light weight manually movable scatold plank comprising parallel side rails and a central rail, said rails being thickened midway their lengths and tapering toward each end, flanges on the rails, spaced upper and lower elongated treat sheets one above the other secured to said anges, whereby the sheets are spaced from each other at their ends and -diverge lfrom each other from the ends inwardly, said central rail being slightly shorter than the side rails, and fillets secured in each end of the plank at the end of the central rail and extending between companion ends of said side rails.

5. A light weight manually movaible scaffold plank comprising longitudinally extending nails, said rails lbeing thickened midway their lengths and tapering toward each end, spaced upper and lower elongated tread sheets one above-the other secured to said rails, whereby the sheets are spaced from each other at their ends and diverge fnom eachother from the ends inwardly, selected ones of said rails being shorter than other rails, and llets secured in each end of the plank at the ends of said shorter rails and -betweenrsaid other rails.

6. A flight weight Imanual-ly movable scaffold plank comprising longitudinally extending rails, said rails being thickened midway their lengths and tapering tovv-ard each end, spaced upper and lower elongated vtread sheets one above the other secured to said rails on opposite surfaces thereof with the thickened dimensions of said rails perpendicular to said sheets thereby lbowing one sheet away for the other from their ends inward-ly to space the sheets apart more at their mid portions than Aat their ends.

References Cited in the file of this patent UNITED STATES PATENTS 81,406 Post Aug. 25, 1868 510,057 williams Dec. 5, 189,3 1,498,176 Lachman June 17, 1924 1,594,658 Bushong Aug. 3, 1926 1,682,883 Black Sept. 4, 1928 2,089,865 Voss Aug. 10, 1937 2,178,762 McLaughlin Nov. 7, 1939 2,296,336 Crozier Sept. 22, 1942 2,479,819 vDe Ragon Aug. 23, 1949 FOREIGN PATENTS 468,855 Canada Oct. 17, 1950 OTHER REFERENCES Machinerys Handbook, 12th edition, 1944, The Industrial Press, New York, New York, p. 414.

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