US2806747A

US2806747A - Adjustable scaffold

Info

Publication number: US2806747A
Application number: US442023A
Authority: US
Inventors: William A Jaeger
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-07-08
Filing date: 1954-07-08
Publication date: 1957-09-17
Anticipated expiration: 1974-09-17

Description

Sept 17, 1957 w. A. JAEGER 2,806,747

ADJUSTABLE SCAFFULD Filed July 8, 1954 2 Sheets-Sheet l q [1 LJ INVENTOR. WILLIAM A. JAEGER FIG. 2

ATTORNEY Sept'17, 1957 W. A. JAEGER 7 2,806,747

ADJUSTABLE SCAFFOLD Filed July 8,. 1954 I 2 Sheets-Sheet 2 INVENTOR. WILLIAM A. JAEGER BY m .1

ATTORNEY United States Patent ADJUSTABLE SCAFFOLD William A. Jaeger, Norfolk, Va.

Application July 8, 1954, Serial No. 442,023

3 Claims. (01. 304-49 The present invention relates to adjustable scaffold structures, and more particularly to scaffolds that may be adjusted to vary the height of the scaffold platform.

it is a principal object of the invention to provide an improved adjustable framework for scaffolds, that is simple in construction and relatively very strong.

Yet another object of the invention is to provide an adjustable scalfold having an improved and simplified adjustable arrangement for adjusting the height of the scaffold.

Further objects and features of the invention will be apparent with reference to the following specification and drawings, in which:

Fig. 1 is a perspective view of the scaffold of the invention;

Fig. 2 is a side elevation of the invention of Fig. 1 showing, in dotted lines, the position of the framework of the scafiold in the upper adjusted position; and

Fig. 3 is a perspective view of a modified form of the invention.

Referring to Figs. 1 and 2 of the drawings, a preferred form of the invention as used for scafiolds, will be described. It should be understood that various details of the construction may be modified within the spirit of the invention, as will be pointed out. A lower planar framework is generally indicated at and an upper planar framework is generally indicated at 11 in a position overlying the lower framework. The lower and upper frameworks 10, 11 may be generally similar to each other and are comprised of side frame members, such as shown at 12, 13, 14 and 15, together with cross brace members 16, 17 and corner brace members 13, 1 and 2t), and a fourth corner brace, not shown. Each upper or lower framework may be suitably fabricated by welding metal tubes or other structural members or other methods of fastening or by bolting metal or wood or other suitable structural units in the generally quadrilateral form, as shown. Of course, each framework 1%}, 11 may be fabricated in a form other than the planar quadrilateral form as shown. For example, circular, trilateral or many sided planar forms may be used. A scaffold platform 21 may be secured to the upper surface of the upper framework 11 in any suitable manner.

A plurality of pairs of scissors cross-legs, generally shown at 25, 34, 35 and 36, are connected between t e lower and upper planar frameworks 10, 11 to provide adjustable legs for supporting the upper framework 11 at an adjustable height above the lower framework 1%. Each pair of scissors cross-legs, such as that generally shown at 25, is comprised of a first leg 26, pivotally connected at 27 to the upper planar framework 11 and a second leg 23 pivotally connected at 29 to the lower planar framework re. The other end of the first leg 26 is pivotally connected at 30 to a connecting member 31 that is slidably connected to the lower planar framework Similarly, the other end of the second leg 2?; is pivotally connected 32 to a connecting member 33 that is slidably connected to the upper planar framework As previously stated, each similar side of the planar frameworks 1t) and 11 may be interconnected by pairs of scissors cross-legs, such as generally shown at 25, 34, 35 and 36 on Fig. 1 of the drawings, thus providing a maximum of structural strength. It is assumed that the upper planar framework 11 is to be maintained generally parallel to the lower planar framework 1%, and therefore each

scissors cross-leg

26, 28 is of equal length and is pivotally connected to the other cross-leg at a point 37 midway of the lengths of the legs.

In order to fix the adjusted height of the framework, it is required to limit or fix the sliding motion of at least one of the slidable connecting

members

31 or 33 for each pair of scissors cross-legs, and this may be readily accomplished in any suitable fashion, such as by the pins 49, 41 which may be removably received in a selected one of the apertures 42, 43 on the respective sides of the upper and lower frameworks. Either one or both of the pins 44 41 will prevent any opening of the scissors cross-legs beyond the adjusted open position, as determined by the selection of the aperture 42 for pin 46 or the aperture 43 for pin 41. Obviously, a more rigid framework will be obtained by providing both upper and lower pins 4% 41 for each pair of scissors cross-legs and selecting cooperating ones of the apertures 42, 43. It should also be understood that friction set screws or the like may be used in place of the pins and apertures.

A simplified form of the invention as adapted to provide a portable scaffold, where great strength is not required, is shown by Fig. 3 of the drawings. As there shown, only two pairs of oppositely positioned scissors cross-legs, generally shown at 50 and 51, are used to interconnect the upper planar framework 52 and the lower planar framework 53. The arrangement is otherwise similar to that previously described in that one end of each leg of a pair of cross-legs is pivotally connected to a selected one of the

frameworks

52 or 53, and both slidably and pivotally connected to the other of the

frameworks

52 or 53. Similarly, an arrangement of

pins

54, 55 and

apertures

56, 57 may be provided to fix the adjusted position of the height of the table framework 52 above the lower or base framework 53.

Various modifications may be made within the spirit of the invention and the scope of the appended claims.

I claim:

1. An adjustable scaffold framework comprising, a lower planar framework, an upper planar framework positioned above said lower framework, a scaffold top secured to said upper framework, at least two pairs of oppositely disposed pairs of adjustable scissors cross-legs, each of the cross-legs being of substantially the same length, means to pivotally connect one end of the first leg of each pair of cross-legs to said upper framework at fixed positions diametrically opposed to each other, means to connect one end of the second leg of each pair of cross-legs to the lower framework at a fixed point beneath the pivotal connection of the first leg to the upper framework, means to slidably and pivotally connect the other end of the second leg of each pair of cross-legs to the upper framework at positions diametrically opposed to each other, means to slidably and pivotally connect the other end of the first leg of each pair of cross-legs to the lower framework at a point beneath the slidable and pivotal connection of the second leg to the upper framework, means to pivotally connect each pair of crosslegs midway of their lengths at the crossing point therebetween, and means to lock the slidable position of at least one of the slidable connections of each pair of scissors cross-legs to prevent opening of each pair of scissors cross-legs beyond an adjusted open position.

2. An adjustable scaffold framework comprising, a lower planar framework of quadrilateral configuration,

an upper. planar framework of quadrilateral configuration positioned above said lower framework, a scaffold top secured to said upper framework, at least two pairs of oppositely disposed pairs of adjustable scissors crosslegs, each of the cross-legs being'of substantially the same length, means to pivotally connect one end of thefirst leg of each pair of cross-legs to a corner of said upper framework at fixed positions diametrically opposed to'each other, means to connect one end of the second leg of each pair'of cross-legs to a corner of the lower-framework at a fixed point beneath'the pivotal connection of the-first leg to the upper framework, means to slidably and pivbtally connect the other end of the second leg of each pair of cross-legs adjacent another corner of the upper framework at positions diametrically opposed :to each other, means to slidably and pivotally connect the other'end of the first leg of each pair of cross-legs adjacent another corner ofthe lower framework at a point beneath the slidable and pivotal connection of the second leg to the upper framework, means to pivotally connect each pair of cross-legs midway of their'lengths at the crossing point therebetween, and means to lock the slidable position of at least one of the slidable connections of each pair of scissors cross-legs to prevent opening of each pair of scissors cross-legs beyond an adjusted open posi tion.

3. An adjustable scaffold framework comprising, a'

leg of each pair of cross-legs to said upper framework at fixed points adjacent a respective corner thereof and positioned so that the fixed position of the opposed pairs of the respective first legs are at positions diametrically opposed to each other, means to pivotally connect one end of a respective second leg of each pair of cross-legs to said lower framework at fixed points adjacent a respective corner thereof the fixed pivotal connections of the respective second legs being ,directlybeneath the pivotal connections of the respective first legs, means to V 317,862 Schrader et a1 May l2, 1885 1,295,194 Parelius L. Feb. 25, 1919 1,670,145 Earrington MaylS, 1928 12,4 6 51 Lo g Aug. ,6, 1,9 7 2,581,023 lerrick Jan. 1, 19 52 ,6 9 :U 'i h --V--.--V----V- ;M Y 2,,1 2,641,247 Genebach June 9, 1953 2,715 ,25 ,Br ttl nd "J m 19, 95

slidably and pivotally connect the othenend of a respective second leg of each pair of cross-legs to said upper framework adjacent a respective corner thereof, means to slidably and pivotally connect the other end of a respective first leg of each pair of cross-legs to said lower framework adjacent a respective corner thereof, means to pivotally connect each pair of cross-legs midway at their lengths at the crossing point therebetween, and means to lock the slidable-positionof at least one of the slidable connections of each pair ofkscissors cross-legs to prevent opening of each pair of scissors cross-legs beyond an adjusted open position.

References Cited in the file of this patent vUNITED STAIES PATENTS