US2468186A - Scaffold - Google Patents

Description

April 26, 1949. A. w. DU FERRET S CAFFOLD Filed April 25, 1946 IN V EN TOR ARTHUR W DURE'RRET kxzi wg ATTORNEY Patented Apr. 26, 1949 PAT 'EN T F Fl CE 'S'CAFFOLD Arthur W. Z'Dn :Pierret, St. Louis, Mo., assignor to Automatic Devices, Incorporated, St. Louis, Mo.,

ame ioration of Missouri Application April 25, 1946, Serial No. 664,850

Slaims. 1

.iBhi-s invention :relates to scaffolds and more nanticularlyito :an improved lportable scaffold and bracing structure "therefor.

Onezofxthexobjects of myeinvention is to produce animproved port'able'scaffold that can be quickly erected and taken "d0Wn-'and yet will be strong and rigid.

.Another ebject is to-produce a portable scaffold in which the bracing members thereof can 'be quickly changed f'rom :one position to another to permit the'scafiold to be=used invarious places,

particularly where there may be obstructions.

Still another object is 'to produce an improved removable br-aoe construction "for a sc'aiiold.

-A further'object is'to produce a scaffold which I erected in a rigid manner to produce a scaffold 5 of any desired height -'or length.

Otherobjects-o'f my invention will become apparent "from the following description taken in connection with the "accompanying drawings in which:

Figure 1 is *aperspec'tive' view of a single unit scaffold embodying my invention;

"-Figure-2 is-e longitudinal section view showing azpreferre'd j'oint construction whereby the height of the posts m-ay be increased;

Figure *3 is :an-erilarged side view showing one end of a brace structure and the manner "it is attached ts -a -post;

Figure 4 *is =a-sectional view taken on the "line 1-4 of Figure B; and

Figure b is a'secti'onall view showin the manner in '-whi'ch a'-plurality of braces can be attached to a:single post when it 'is desired'to have removable end frame brace structure and also a scaffold embodying several units.

Referring to the drawings in detail and first to Figures'slto 4, inclusive,- the scaffold unit shown asvem'bodying-my invention has two end frames El and .2 0f .like construction. Each of these end frames hastwo posts 3 and-:4 which are shown as being tubular. The posts 3 :and "4 of each end \framehave their'upper ends connected by a horizontal crossbar 5 welded to the posts some distanceifrom theupper end. In order to make this cross rbarzmore rigid, angular braces 6 and Textend betweenthesposts and the crossbar 5 inthe manner shown. These braces may have any desired "cross sectional shape and one end of each 'sbracetis welded to aapost and the other end to orossban'a't as'point'spacedlinwardly from the braces 9 and it] each have "their ends welded itcthe post and .the cross bar as shown. The end frames, as thus aconstructed, :are very rigid.

In order :.to complete the scaffold unit structure a plurality of stringers S :are employed to Join the end frames in spaced apart :relation. :Each ofthese :stringers is of like construction :and each is arranged to have its ends connected to anlend trame by iremovab'le .means .so that the scaffold can "be erecteduand taken down as .desired.

:Each stringer S is formed with za cross bar 1H which maybe of any desired .cross section and of a length corresponding to the spacing desired between the end frames. As shown, this :cross bar l! is of tubular construction. The ends of the crossbar have secured thereto members 21:2 and ['3 of considerable length. These members are shown as'hav'ing a curved cross section and are arranged to*be at right angles to the-axis of the cross bar 1 I with the "joints between the members l2 and i3 and the cross bar being adjacent the upper ends of the members. Between the member 12 and the cross bar is an angular brace t and between the member E3 and the crossbar is an angular brace l'5. 'Thebraces are permanently-secured to the cross bar and the members as by welding and maybe of any desired cross sectional shape. With'the stringers S constructed as shown, they are arranged to be attached to the posts of the end -frames by means of suitable removable means such as bolts 16 having wing nuts '17, which bolts extend through holes T8 in the end posts.

The two'posts 4 of the two end-framesarenonnected adjacent their tops by a stringer Sand adjacent their bottoms by another stringer S. Similarly -'st1-ingers S connect the posts 3 of the end frames 'a'djacer'it their tops andbottoms. Cit is tobenotedthatthe curved members i 2=-and 13, at the endsof each cross .bar .11 of 'the'stringers, have their inner cylindrical surfaces facing outwardly from the end of thecross bar and when the cross baris attached to the end posts theend posts will be received in the recesses oi-the members l2 and 13 as best illustrated in'Figure-4. In "order that there will be a tight connectionibetween the end' posts and themembers l2-and 43 at the-ends of the stringers whenever the bol-ts'fl fi are tightened up, the radius-of curvature -of the inner surface of the member l2 is'slightly'smaller than theradius of curvature of the surface-o'f the tubular members forming theposts. -".Phus when the bolts are drawn up tight the surface of the post will have wedging in the members l2 or [3 with an accompanyin spreading action and there will be produced a clamping action which will result in a rigid and tight connection. The relationship between the radius of curvature of one of the members, such as l2, and the radius of curvature and the surface of the post with which it cooperates is illustrated in Figure 4.

In order to provide a platform for the scaffold, planks P may be laid across the upper cross bars 5 of the two end frames. These planks can have angle cleats 58 so as to prevent them from shift-- ing on the cross bars. If it is desired to have the scaffold easily movable about as, for example, when used for interior work, the bottoms of the end posts of both end frames can be provided with casters is.

Under certain conditions it may be desirable to increase the height of the scaffold unit which has just been described, and to accomplish this the upper ends of the end posts which project above the cross bars 5 have welded thereto sleeves of an internal diameter to fit over the ends of the posts. which can be slipped tubular members 2i having the same external diameter as the posts. The tubular members 2! to be associated with the end posts of each end frame are connected together by a cross bar 22 welded to the tubular members as shown. There is also provided wood cross members 23 which can be secured by bolts 2t to the tubular members. The cross bars 22 and the cross members 23 thus provide a higher structure upon which a plank or planks, such as the plank 25, can be placed. If it should be desired to put several scaffold units on top of the scaffold unit already described, these units will be constructed in the same manner as the single unit except that the casters are eliminated from the bottoms of the legs. Such a unit, or units, can then be set on top of the base unit by inserting the corner posts of the end frames in sockets provided by sleeves 20 at the tops of the end posts.

The scaffold just described can be used in almost any desired place and is adapted for many uses by merely changing the position of the stringers. If it should be desired to push the scaffold unit over an object on the floor, the scaffold can be conditioned for this by having its lower stringers S raised up to a height so that they will clear the object. Such position of the two lower stringers is shown by the dotted lines in Figure 1. Each post is provided with bolt holes is in longitudinally spaced relation on the end post to permit this shifting of the lower stringers. If it is desired to lower the two top stringers, such can be quickly accomplished. If it is not desired to use the upper extension formed by the tubular members 2! and the cross pieces 22 and cross members 23 as, for example, in a room with a low ceiling, then these pieces can be quickly removed by lifting the tubular members out of the sockets provided by the sleeves Furthermore, if it should be desired to lower the main platform, which is indicated by the planks P, this can be done by taking the wood cross members 23 and bolting them on the end frames below the cross bars 5, using the holes is for receiving the bolts 24. Such a positioning of the wood cross bars 23 is shown in dotted lines in Figure 1. The planks P will then be placed upon these cross bars 23.

If it should be desired to have the cross members '5 and 8 for the end frames removable in- These sleeves provide sockets into stead of permanently secured to the posts 3 and 4, as shown in Figure 1, end constructions similar to the end constructions of the stringers S can be employed on the cross bars 5 and 8 and then cross bars attached by means of bolts. Such an arrangement is illustrated in Figure 5 wherein, in addition to the stringer S attached to an end post 2t, there is provided a stringer S which is a removable stringer for connecting the two posts of the end frame together, it being understood that there is another post similar to the post 26 which, together with the stringer S, forms part of the end frame. The stringer S has its end constructed in the same manner as the stringer S illustrated in Figure 3 and a bolt 21 and Wing nut 28 are provided for securing the end of this stringer to the post.

If it should be desired to add additional sections on the scaffolds to lengthen it, then this can be accomplished by merely connecting additional stringers to the end posts as also illustrated in Figure 5. For example, the stringer S can be secured to the opposite side of the post 26 from the end of stringer S. The same bolt I6 can be employed to connect the stringers S and S to the post. With such an arrangement it is seen that the scaffold can be built of any desired length with adjacent sections having common end frames. The stringers S and S between the end frames can be so attached to their posts as to be out of line if desired. When several stringers are to be attached to a single post in a manner illustrated in Figure 5,, the curved members which cooperate with the post have an arch which is slightly less than the quarter of a circle so there will be s-ufiicient room for all of these members to fit around the post.

In the scaffold illustrated the post members are shown as being tubular, but it is to be understood that other cross sectional shapes can be used and also other cross sectionalshapes for the end members l2 and 3 for the stringers can be used to cooperate with these posts to obtain a fit when the stringers are bolted thereto. For example. the posts may have a square cross section and the shape of the members l2 and I3 may be angular so that the one corner of the post will be received in the angular portion of the members l2 or it. The angle of the members I2 and is should be slightly less than degrees so as to obtain the same clamping action as is obtained by the difference of radius in curvature of the round posts and the end members l2 or it as illustrated in Figure 4. Therefore, being awar of the possibility of modification in the particular structure shown and described, without departing from the fundamental principles of my invention, I do not intend that the scope of the invention be limited in any manner except in accordance with the appended claims.

What is claimed is:

1. In a scaffold unit, a pair of end frames each of which comprises a pair of posts and bracing between the posts including platform supporting and means for joining the end frames together comprising upper and lower stringers connecting each post of one end frame with a post of the other end frame, each of said Stringers including a bar, an elongated member permanently secured to each end of the .bar and provided with a longitudinal exposed grOOVe having its axis at right angles to the longitudinal axis of the bar, removable means for clamping the elongated member to a post with the post received in the longitudinal groove, each groove and post having such cooperating relationship and the clamping means being so associated with the post and member that said clamping means can cause the post to wedge into the groove with a spreading action thereon, and means comprising spaced holes in the post for cooperation with the removable clamping means for permitting the elongated members of at least two of the stringers to be attached to their posts at diiferent points on the posts.

2. A detachable stringer for connecting and bracing spaced round posts of a scaffold, said stringer comprising a bar, an elongated member permanently secured to each end of the bar and having a curved surface the axis of which extends longitudinally of the member and at right angles to the longitudinal axis of the bar and the radius of curvature of which is slightly less than the radius of curvature of the surface of the end post, and means for associating detachable connecting means with each longitudinal member to thereby clamp the elongated member to a post with the curved surfaces adjacent the post surface, said detachable means when producing a clamping action causing the elongated members to yield in a manner to increase the radius of curvature of the curved surface.

3. A detachable stringer for connecting and bracing spaced round posts of a scaifold, said stringer comprising a bar, an elongated member permanently secured to each end of the bar and having a curved surface the axis of which extends longitudinally of the member and at right angles to the longitudinal axis of the bar and the radius of curvature of which is slightly less than the radius of curvature of the surface of the end post, a brace element between each elongated member and the rod with its ends permanently secured to the member and red at points spaced from the connecting point of the rod and member, and means for associating detachable connecting means with each longitudinal member to thereby clamp the elongated memher to a post with the curved surfaces adjacent the post surface.

4. A detachable stringer for connecting and bracing spaced posts of a scaffold, said stringer comprising a bar, an elongated member permanently secured to each end of the bar and having an outwardly facing roove the axis of which extends longitudinally of the member and at right angles to the longitudinal axis of the bar, said groove having a surface contour similar to the post surface with which it is to cooperate but being of such less cross width than the post at corresponding points that when clamped to the post the post will have a spreading action on the side walls thereof, and means for associating connecting means with the elongated member for clamping it to a post and to cause a spreading action to occur.

5. A detachable joint structure for connecting a scaffold stringer to a scaifold post, said joint comprising an elongated member welded to the bar at one end thereof and provided with an exposed longitudinal groove at right angles to the axis of the stringer, said roove having such a width between the outer edges of its walls that said edges will engage the post surface without the bottom of the groove engaging the post surface, and bolt means extending through the elongated member and the post for clamping the member to the post and causing the post to apply a spreading force to the opposed walls of the groove.

ARTHUR W. DU FERRET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,828,487 Booser Oct. 20, 1931 1,920,130 Pease et al July 25, 1933 2,126,720 Beatty et al Aug. 16, 1938 2,303,428 Black Dec. 1, 1942 2,305,563 Uecker et a1 Dec. 15, 1942 2,308,831 Roney et al Jan. 19, 1943 2,311,988 Lavin Feb. 23, 1943 2,361,614 Dugan et al. Oct. 31, 1944 2,363,382 Attwood Nov. 21, 1944 2,406,078 Hushower Aug. 20, 1946 v FOREIGN PATENTS Number Country Date 507,454 Germany Sept. 22, 1930

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