US3235038A

US3235038A - Folding scaffold

Info

Publication number: US3235038A
Application number: US271971A
Authority: US
Inventors: Fritz J Nesslinger
Original assignee: Harsco Corp
Current assignee: Enviri Corp
Priority date: 1963-04-10
Filing date: 1963-04-10
Publication date: 1966-02-15
Anticipated expiration: 1983-02-15
Also published as: GB1067274A

Description

F. J. NESSLINGER Feb. 15, 1966 FOLDING SCAFFOLD 5 Sheets-Sheet 1 Filed April l0, 1963 Feb. 15, 1966 F. J. NEssLlNGER FOLDING SGAFFOLD 5 Sheets-Sheet 2 Filed April l0, 1963 NVI".

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MMMJW Feb. 15, 1966 F. J. NEssLlNGER FOLDING SGAFFOLD United States Patent() 3,235,038 FOLDING SCAFFOLD Fritz Il. Nesslinger, College Point, N.Y., assignor, by

mesne assignments, to Harsco Corporation, a corporation of Delaware Filed Apr. 10, 1963, Ser. No. 271,971 4 Claims. (Cl. 182-62.5)

The present invention relates to folding scaffolds, more particularly of a mobile type capable of being readily folded and extended by one person.

An object thereof has been to provide a relatively light weight mobile unit which can be made in an adequate range of sizes at relatively moderate cost and which will afford optimum safety, yflexibility and facility in handling.

A scaffold according to this invention comprises in general two end frames which are permanently connected at one side, as the front, by interposed pivotally interconnected cross or side braces and at the opposite side, as the rear, by an interposed top brace. Each of said side and top braces includes two tubes each of which is pivoted at its outer end to one of said frames; and the inner ends of said tubes constituting each brace are connected by a link hinge. Means movably mounted on said braces are positioned to releasably lock said hinges against flexing when the end frames and braces are adjusted to extended position. Each of said side braces includes a long tube and a short tube, said long tubes being pivotally interconnected advantageously at a distance from said hinge connection with the short tubes which distance is less than the length of said short tubes.

A scaffold of the foregoing construction and having the advantages above referred to is described in this specification and shown in the accompanying drawings. Such disclosure is supplied for illustration so that others skilled in the art may fully understand the invention, its principles and its manner of application in practical use. In said drawings:

FIGURE l is a front elevation of a scaffold embodying the invention `and as it appears when in unfolded or extended condition, the parts being proportioned for a unit approximately six feet high and extendable to a span of approximately six feet;

FIG. 2, a top plan View;

FIG. '3, a front elevation with parts broken away showing the relative positions of the parts when the scaffold is in partly extended condition;

FIG. 4, a front elevation, showing the scaffold in folded condition; and

FIGS. 5 and 6 are front elevations, in part diagrammatic, showing the relative proportions in length of parts, respectively, of a six foot high scaffold having an extended length of approximately eight feet (FIG. 5), and a six foot high scaffold having an extended length of approximately ten feet, FIG. 6.

Referring to FIG. 2 of the drawings, a scaffold according to the invention comprises end frames A and B which include, respectively, front uprights a and 10b and

rear uprights

10 and 10" connected to said front uprights by intermediate rungs 11, FIG. 4, and top rungs 11a and 1lb, respectively. Casters 12 are provided to support said uprights; and brakes 13 are operatively related to said casters.

Said end frames A and B are permanently connected by a set of cross braces at the front side of the scaffold and by a rear top brace at the rear side thereof. Each of said cross -braces includes a long tube and -a short tube, said long tubes of a set being pivotally interconnected by a pivot fitting 16.

One of said front or cross braces includes the long tube 14 and short tube 15; and the other of said front braces includes the long tube 14' and short tube 15. In each Patented Feb. I5, 1966 "ice front brace, the long tube is hinged to its short tube by a link hinge 17.

As seen in FIG. 2, long tube 14 is pivoted to top rung 11a of end frame A at 18; and long tube 14 is pivoted to an upper end portion of upright 10b of end frame B at 18'. Short tube 15, FIG. l, is pivoted to rung 1I of end frame B at 19; and short tube 15 is pivoted to an intermediate portion of upright 10a at 19.

Said rear top brace which permanently connects frames A and B comprises tubes 20 land 20. The outer end of tube 20, FIG. 2, is pivoted to rear upright 10 of frame A at 21; and the outer end of tube 20 is pivoted to rear upright 10 of end frame B at 22. The inner ends of said

tubes

20 and 20 are operatively connected by a link hinge 23.

Each of the above described cross braces also includes, FIG. 2, a locking sleeve 25; and the rear top brace includes a locking sleeve 25. Each of said sleeves is rotatable and slidable endwise on said tubes to and from locking position wherein it embraces a link hinge, as 17, and overlaps adjacent ends of the tubes which are connected by said hinge. A stop pin 26 on one tube, as short tube 15 of one cross brace, serves to limit the extent of sliding movement of sleeve 25 when it reaches locking position across hinge 17, FIG. l. A similar stop 26 is provided on tube 15. An L-shaped slot 27, FIGS. l and 3, in each of sleeves 25 engages a locking pin 24 on each of the

long tubes

14, 14 to releasably lock said sleeves in inoperative or retracted position, as when the scaffold is in folded condition or is being adjusted toward said condition, FIG. 3.

As seen in FIG. l, the top rear brace locking sleeve 25 is provided with L-shaped slots, as 28, 28', one at each end and so arranged that slot 28 engages a locking pin 29 on tube 20 when the rear brace is extended; and slot 28 engages locking pin 29' when the brace is being folded, FIG. 3, and when the scaffold and rear brace are in folded condition, FIG. 4.

The apparatus shown in FIGS. l through 4 is based on dimensions and proportions of the component parts appropriate to a six foot high scaffold extendable to a six foot span, i.e. the distance between end frames A and B. For an eight foot span scaffold of the same height, as schematically indicated in FIG. 5, the long tubes, as 14a, 14a', of each cross brace are longer than those employed in a six foot span unit; and for a ten foot span unit, the long tubes, as Idb, 14h', are still longer, as indicated schematically in FIG. 6. In any case, each of said long tubes is pivoted to its cooperating long tube at a point where the pivot connection between them, as 16, is located at a dist-ance from hinge 17 which is less than the effective length of the cooperating short tube, as 15a', 15a, FIG. 5, and 15b', 15b, FIG. 6, respectively. As indicated in FIG. 5, the upper end of long tube 14a is pivotally connected to an upper end portion of end frame A at 18; and the upper end of long tube 14a is pivotally connected to an upper end portion of end frame B at 18'. The upper ends of

short tubes

15a and 15a, respectively, are pivotally connected to intermediate portions of end frames A and B at 19 and 19, respectively.

As indicated in FIG. 6, the upper ends of long tubes 14b and 14b are pivotally connected to` upper end portions of end frames A and B at 18 and 18', respectively, while the upper ends of short tubes 15b and 15b are pivotally connected to intermediate portions of said end frames A and B at 19 and 19 respectively. The pivotal connections of said tubes with the frames and between the cooperating long tubes, as indicated schematically in FIGS. 5 and I6, may advantageously be of the type shown in more detail in FIGS. 1, 2 and 3 for the long tubes 14,

'14 and

short tubes

15 and 15.

The above described arrangement permits folding and nesting of the component tubes with the end frames in compact assemblies of substantially uniform height and overall circumferential dimensions.

It is noted that in longer span embodiments, the rear top brace tubes are correspondingly longer than in a six foot span device. Accordingly, where six feet, for example, is regarded as approximately the optimum height for scaffolds of the subject type both in use and for mobility, the end frames, short tubes, casters, sleeves, hinges etc. are supplied as standard parts in standard sizes. These are advantageously assembled with appropriately dimcnsioned rear top brace tubes and long cross tubes to provide different units extendable to different span lengths, as 6, 8 and 10 feet, for example. Under these conditions, considerable economies may be effected in tooling and inventory costs.

The above described embodiments of the subject invention also present substantial advantages in use. Thus, under usual or normal conditions, this scaffold may be adjusted from folded (FIG. 4) condition to extended (FIG. l) condition by one operator without braking or locking any caster. However, where advisable under special conditions, as where the scaffold is in use on a grade, one or more casters may be braked to advantage.

With the casters free to roll and the parts in folded condition, FIG. 4, to extend the scaffold to operative condition, latch 30 is released and the end frames are moved apart initially to an extent as indicated in FIG. 3, or so that the sleeves 25 may be firmly grasped by the operator. By applying spreading or unfolding force through said sleeves to lower end portions of the long tubes 20, the operator adjusts the cross braces simultaneously to extended condition. Said Isleeves are now disengaged from pins 24 and moved along their respective long tubes across hinges 17 and rotated to the locking positions fixed by stop pins 26, FIG. 1.

The operator is now able to adjust the rear top brace to extended condition where it is locked by sliding sleeve 25 toward the right, FIG. 1, from its retracted position across hinge 23 and by rotating said sleeve to engage slot 28 thereof with pin 29 on tube 20'.

The above described extending operation of the cross braces is greatly facilitated where the sleeves 25 are so arranged on the long tubes that the spreading force may be most effectively applied and controlled continuously at all angular positions of said tubes as they swing from their FIG. 3 to their FIG. l positions.

To adjust the scaffold to folded condition, FIG. 4, from its extended condition, FIG. 1, sleeve 25 is disengaged from pin 29 and withdrawn to the left, FIG. 2, and rotated to engage slot 28 with pin 29', thus freeing the hinge joint at 23 for flexing. The sleeves 25 are then moved upwardly on the long tubes and are rotated to bring slots 27 into locking engagement with pins 24, thus to free the hinge joints 17 for flexing. The operator now moves end frames A and B toward each other on casters 12. This causes the rear brace hinge joint 23 and the front brace hinge joints 17 to move downwardly while the pivoted outer ends of the rear brace tubes 20, 20' swing toward each other to folded condition; and the pivoted ends of long brace tube 14 and short brace tube 15 swing toward each other; and the pivoted ends of long brace tube 14 and short brace tube 1S swing toward each other, all substantially simultaneously until the brace parts are brought into the compact, or in effect, nested relation shown in FIG. 4. A latch 30 pivoted at 31 on a rung 11 of frame A, FIGS. 2 and 3, is engaged with a keeper 32 on a rung of frame B, FIG. 4, to retain the above described end frames and braces in compact or folded condition, FIG. 4, so that the scaffold may readily be moved from place to place either on its casters or transported as a compact unit by truck or other suitable means.

An advantageous degree and an effective continuity of control are thus available in folding and extending the above described scaffold because the parts are, in effect, in continuous substantially balanced or symmetric relation. Also, the end frames being connected by the braces, as described, neither frame can be moved for adjustment to and from operative position without a corresponding movement by the other frame. These features contribute materially to safety from injury to operators in manipulating the scaffolds.

I claim:

1. Folding scaffold comprising a pair of end frames, a rear top brace operatively mounted between said end frames, and two tubular front side braces operatively interposed between said end frames each of which connects said end frames at the front side of the scaffold and includes a long tube pivoted at its outer end to an upper portion -of one end frame and a short tube pivoted at its outer end to a lower intermediate portion of the other end frame, said long tubes being permanently pivotally interconnected between their ends, and each of said long tubes being operatively connected at its inner end to the inner end of a short tube by a link hinge Voperatively interposed between said pivotal interconnection and the pivotal connection of said short tube to its end frame, and a sleeve freely slidable and rotatable on each long tube between said hinge and said pivotal interconnection between the long tubes and, when said long and short tubes of a brace are axially aligned, being slidable to and from a position embracing said hinge and with its ends overlapping the connected inner ends of said long and said short tubes, a detent on the corresponding short tube arranged to stop said sleeve in locking position across the hinge, a detent on the long tube, and means on the sleeve cooperating with said last mentioned detent toI releasably retain said sleeve out of locking relation to the hinge.

2. A scaffold as defined in claim 1 and wherein the reartop brace comprises two rear tubes of substantially equal length each pivotally connected at its outer end to one of said end frames, said rear tubes being joined at theirl inner ends by a link hinge, a sleeve rotatable on said rear' top brace and slidable to and from a position extending across said link hinge, and means arranged and adapted for releasably locking said rear tubes in extended sub-- stantially straight condition between said end frames, said front side brace parts and said rear top brace parts being so proportioned and operatively arranged in connectionV with said end frames that, when said end frames and braces are brought to folded condition, all said brace parts are nested between said end frames with said tubes in compact substantially parallel relation therewith and. with each other.

3. A folding scaffold of the type wherein end frames arey permanently operatively connected by braces arranged in crossed relation at the front side of the scaffold and by a brace at the rear side thereof, said rear brace includingv two tubes of substantially equal length hinged together at their inner ends and operatively interposed between opposed top rear end portions of said end frames, and said crossed braces being operatively interposed between opposed front portions of said end frames, each of said crossed braces comprising a long tube and a short tube hinged at its inner end to the inner end of said long tube, the outer end of each said long tube being pivotally connected to an upper front portion of one of said end frames and the outer end of the short tube hinged thereto being pivotally connected to an intermediate portion of the other end frame, and said long tubes being permanently pivotally interconnected for relative angular movement around said pivot connection during adjustment of the scaffold to and from operative condition.

4. A folding scaffold as defined in claim 3 and wherein the distance between said tube interconnecting pivot connection and said hinge connection of the long tube with 5 6 the short tube is not greater than lche effective length of 742,755 -10/'1903 Uffelman. the short tube. 2,982,379 '5/ 1961 Fisher 189-19 3,000,466 9/'1961 Johnston et al. 182--152 X References Cited by the Examiner UNITED STATES PATENTS 5 HARRISON R. MOSELEY, Primary Examiner.

393,210 11/ 1888 Chapman 24S-436 X REINALDO P- MACHADO, Examiner-

Claims

3. A FOLDING SCAFFOLD OF THE TYPE WHEREIN END FRAMES ARE PERMANENTLY OPERATIVELY CONNECTED BY BRACES ARRANGED IN CROSS RELATION AT THE FRONT SIDE OF THE SCAFFOLD AND BY A BRACE AT THE REAR SIDE THEREOF, SAID REAR BRACE INCLUDING TWO TUBES OF SUBSTANTIALLY EQUAL LENGTH HINGED TOGETHER AT THEIR INNER ENDS AND OPERATIVELY INTERPOSED BETWEEN OPPOSED TOP REAR END PORTIONS OF SAID END FRAMES, AND SAID CROSS BRACES BEING OPEATIVELY INTERPOSED BETWEEN OPPOSED FRONT PORTIONS OF SAID END FRAMES, EACH OF SAID CROSS BRACES COMPRISING A LONG TUBE AND A SHORT TUBE HINGED AT ITS INNER END TO THE INNER END OF SAID LONG TUBE THE OUTER END OF EACH SAID LONG TUBE BEING PIVOTALLY CONNECTED TO AN UPPER FRONT PORTION OF ONE OF SAID END FRAMES AND THE OUTER END OF THE SHORT TUBE HINGED THERETO BEING PIVOTALLY CONNECTED TO AN INTERMEDIATE PORTION OF THE OTHER END FRAME, AND SAID LONG TUBES BEING PERMANENTLY PIVOTALLY INTERCONNECTED FOR RELATIVE ANGULAR MOVEMENT AROUND SAID PIVOT CONNECTION DURING ADJUSTMENT OF THE SCAFFOLD TO AND FROM OPERATIVE CONDITION.