US2991854A - Scaffolding - Google Patents

Description

w. M. DuBois ErAL 2,991,854

SCAFFOLDING 4 Sheets-Sheet 1 July 11, 1961 Filed July 8, 1959 QTTOEA/S July 11, 1961 w. M. DuBois ETAL SCAFFOLDING 4 Sheets-Sheet 2 Filed July 8, 1959 Y /NvENm/QS, .maar Sway La-f @We M7- M1 6a n-noe/uy 4 Sheets-Sheet 3 Filed July 8, 1959 July 11, 1961 w. M. DuBois ETAL 2,991,854

SCAFFOLDING 4 Sheets-Sheet 4 Filed July 8, 1959 /N VEN TOBS .m MM d m V www n 6 United States Patent O 2,991,854 SCAFFOLDING Walter Marcel Dubois, Sandy, and George Henry Hale,

North Ilarroyv, England, assignors to British Building and Engineering Appliances Limited, Sandy, England, a

British company Filed July 8, 1959, Ser. No. 825,739 Claims priority, application Great Britain July 10, 1958 7 Claims. (Cl. 189-15.5)

This invention relates to scaiolding.

Scaffolding when erected for use comprises standards (which may be in the form of individual upright poles or which may be parts of frame units) and which bear the weight or part of the Weight of the superposed components of the scaffold structure, between which standards are connected horizontally extending (or approximately horizontally extending) ties of which those which bear a load are normally termed ledgers and which include other forms of tie such as handrails, such ledgers and handrails extending generally parallel to the wall ,or upwardly extending structure adjacent to which the scaffold structure is erected, the ties being normally termed transoms or putlogs when extending perpendicular or transversely to such wall or upwardly extending structure (-and which again may be either individual tie poles or parts of frame units). i

The invention is primarily applicable to scaffolding formed of tubular metal poles or it may be applied in cases where the poles are of some other form, for example constituted Iby metal bars of solid cross Section or girders of angle or channel section. i

Hitherto scaffold poles (whether in the form of individual poles or constituted by parts of frame units) have normally been secured together in an erected scaffold structure by the provision of clamping devices at the junctions or intersections of the standards and ties such clamping devices incorporating means such as screws, wedges, or the like mechanisms to enable the clamping devices to be tightened and released to attain the required rigidity in the built up scaffold structure and to permit this to be taken down when required, in units consisting either of the individual poles or of the frame units.

In building a scaiold structure from scaffolding of this known form a certain amount of time is of necessity expended in tightening the clamping devices, which time is significant in relation to the total time required vto bring each unit of the scaffold structure into position and assemble it in correct relationship with other units. Furthermore, the degree to which each clamping device is tightened determines the rigidity and strength of the scaffold structure as a whole, and this lfactor varies with the particular type of clamping device used and skill, knowledge, and attention paid by the user to the erection operation and in particular to the degree of tightening to be applied in the case of each clamping device. Furthermore, it is possible for clamping devices to be over-tightened and damage the mechanism by which tightening is effected, especially in the case of screws.

Certain of the above mentioned factors are also applicable in releasing the clamping devices when it is required Y to take the scaffold structure down, additionally to whichv rice structure are retained in assembled relation by the weight of the structure. l

A further object is to provide an attachment between the separate standard poles in superposed relation and to j provide for the transmission of compressive loads at suchi attachment.

Another object of the present invention is to provide at f tachment between separate poles or separate frames whether they be superposed one upon another or whether they be laterally disposed on to another in a scaiioll structure.

A further object is to provide attachment for a haiidrail'f'f'v which is not adapted to bear any appreciable amount of"v weight of the structure or other loading.

To this end auxiliary securing means 1s provided.

advantageously A further object is to provide a plurality of attachmentv elements on a pole in order that a plurality of poles may be attached at various angles to a first pole. Y

Another object is to provide means for preventing or v diminishing relative rotation of one part to another when 'I the parts are assembled into a scaffolding structure.

Other and further objects will become apparentzhere-4 inafter.

automatically retains the attachment elements in interiitting engagement.

The invention will now be invention.

FIGURE 2 is a fragmentary view on an enlarged scale and partly in vertical cross section illustrating gie in e junction between a tie member and a standard structure illustrated in FIGURE 1. n

`FIGURE 3 is a fragmentary perspective` view of one form of scaffold pole intended for use as a standard pole embodying one form of the invention.

FIGURE 4 is a plan view in cross section on the line-` 4-4 of FIGURE 3.

FIGURE 5 is a fragmentary view illustrating one form Y of securing means which may be provided on a handrail,

and

4FIGURE 6 is a view similar to FIGURE 2 illustrating a modification of the scaffold structure utilising separate l poles and transoms instead of frame units.

FIGURE 7 is a fragmentary perspective view of a'n alternative form of junction between vertical and horizontal members.

Referring rstly to FIGURE 1 the scaffold structure"E therein illustrated incorporates upper and lower stages 10 and 1'1, of which the lower may rest on the ground.

The scaffold structure comprises a plurality of laterally spaced upright standards 12 which in practice will be positioned immediately adjacent to the upwardly extending wall or structure adjacent to which the scaifold struc.Y

ture is built and a corresponding number of similar upright standards 13 which will be spaced away perpendicularly from said Wall or structure. v

The standardsl 12 are composed of separate standard poles comprising upper poles 12a, lower poles 12b and .l foot poles 112C, whilst the standards 13 similarly` comprise, i

upper and lower poles 13a, 13b and foot poles 13e.,

The poles .12a and 13a form component partsuof' arf frame unit pertaining to the upper stage 10 of the scaffold described by way of ex-r ample with reference to the accompanying drawingsA wherein:

FIGURE l is a perspective view of a scaffold struc ture composed of scaffolding embodying one form of the u structure, whilst similarly the poles 13b form parts of a frame unit pertaining to the lower stage in each case the poles being permanently connected by transoms 14a and 14b respectively braced with respect to the poles by bracing lements 15a to 18d and 15b' to 18b respectively. It will be observed thatthe bracing elements are joined with their respective transoms at positions spaced apart lengthwise ofthe transoms sufliciently far from the centre of the length of each to provide a clear walk-through space in each stage and 11 of the scaffold structure, the bracing elements similarly being connected to the upright poles of the frame concerned at positions about midway between the upper and lower ends of the poles.

The poles, transoms and bracing elements may be formed of tubular metal stock such as mild steel and may be secured together at their points of junction by welding.

The upper stage 10 of the structure is braced by ledgers extending parallel to the face of the wall or upwardly extending structure adjacent to which the scaffolding is erected, those ledgers at the outer sides of the scaffolding structure, that is to say remote from the wall or building, being in the form of frame units 19, whilst at the inner side of the structure the ledgers are in the form of individual ledger poles 20.

At a position midway between the upper and lower ends of the poles 13a or approximately at this position handrails are provided. In lpractice handrails are normally provided only at the outer side of the scaffold structure, but in the drawing they have been shown at both inner and outer sides merely for the purposes of illustrating differing constructional forms. The handrails are indicated at 21 in the case of the outer side and 22 inthe case of the inner side.

Although an identical arrangement could be adopted in respect of the ledgers provided in the lower stage of the structure, alternative forms of components have been illustrated for the purpose primarily of showing the clifferent kinds of ledgers which may be employed; thus at the outer side of the structure in the lower stage the ledgers may comprise frame units 23 which are of twice or approximately twice the height of the frame units 19 so that as hereinafter described the upper ledger pole in each of these frame units 23 can also be utilised as a handrail.

At the inner side of the scaffolding the standard poles are connected in the lower stage 11 by handrails 24 of a somewhat different type to the handrails 22 of the upper stage.

The foot poles .12e and 13C may terminate at their lower ends in foot elements 12d and 13d respectivelyl which may be in the form of plates or blocks providing a substantial area of contact with the ground sufficient to enable the ground to support the weight of the scaffold structure without sinking in.

The construction and arrangement of attachment elements provided to enable the ledgers to be joined to the standards is similar in principle in the case of each of the ledgers 19, 20 and 23, although differing somewhat in detail in each of these cases by virtue of the constructional differences which exist as between these ledgers themselves.

The attachment elements provided respectively on the poles 12a and 12b and on the associated ledger pole 20 are, however, illustrated in greater detail in FIGURE 2 to which reference will now be made, the difference adopted in applying similar attachment elements to the other forms of ledger being hereafter explained.

The attachment elements provided on the pole 12a comprise socket elements 25 and 26 which conveniently may be formed of short lengths of tube typically about 4 inches in length welded to the pole 12a at opposite ends in a direction perpendicular to the plane of the frame unit which embodies the poles 12a and 13a. These socket elements are of constant internal diameter throughout their lengths.

As a possible alternative, f socket elements having a diameter which varies along the length of the socket element concerned may be employed, for example the socket elements 25 and 26 may have internal faces which are convergent in anupward direction. Also it is not essential that the socket elements should be of circular cross section internally, they could be of square or rectangular cross section as for example may be constituted by welding individual stirrups or U-shaped lengths of strip metal against the pole 12a with the free ends of the limbs of each such stirrup or U-shaped piece contacting and welded to the exterior face of the pole 12a.

The pole 12b has welded thereto socket elements 27 and 28 which are preferably similar in form to the socket elements 25 and 26 and are arranged with their axes in vertical alignment with the latter in the assembled scaffold structure.

For co-operating with the socket elements the ledger pole 20 is provided with spigot elements which conveniently but not essentially may be constituted by the end portions of a short length of tube 29 which may be of the same internal and external diameter as the ledger pole 20 itself (and also the standard poles 12a and 12b). The end portions which constitute the spigot elements, as indicated at 30 and 31 may be of reduced external diameter compared with the intervening portion of the tube 29 and produced by swaging these end portions down to this diameter in the known manner.

I'he spigot elements 30 and 31 may be united with the main central portion 32 of the tube 29 through frusto-conical or similarly convergent portions 33 and 34 respectively, conveniently by forming the spigot elements as swaged down portions of the tube 29. The external faces of the convergent portions 33 and 34 constitute stop faces for engaging the inner rim at the mouth of each socket element as defined by the intersection of the inner face of the socket element and its axially directed end face as indicated at 35 and 36 respectively for the two socket elements.

In practice the external diameter of the spigot elements 30 and 31 is made slightly less than the internal diameter of the socket elements 25 and 27, so that despite manufacturing tolerances the spigot elements can always be entered into the socket elements to intertit therewith longitudinally of the poles 12a and 12b without the necessity for the user exerting pressure or hammering and consequently without the user encountering undue resistance to disassembly when it is required to take down the scaffold Structure.

The outer faces of the frusto-conical or ared portions 33 and 34 consequently perform a particularly usefulfunction in taking up any lateral play or looseness as between the socket elements and the spigot elements, the angle of inclination of each of these portions 33 and 34 being suiciently great in relation to the axis of the spigot elements to substantially avoid any risk of jamming between the spigot elements and socket elements.

Furthermore, if desired, the faces 35 and 36 of the socket elements may include one or more slots or notches into which can enter an associated keying part on the spigot element concerned to provide positive location and resistance to relative rotation between the socket element and the spigot element concerned.

Such keying part may be constituted by a lug on the outer face of each of the frusta-conical portions 33 and 34 or possibly by a part of the ledger pole 20 itself, in which case it would be necessary to extend the lengths of the socket elements so as to bring the faces 35 and 36 close to the upper and lower sides of the ledger pole 20.

The poles 12a and 12b may, and preferably are, themselves adapted to interlit longitudinally by the provision'Y on the pole 12a of a spigot element 37 which enters a complementary socket element constituted by the upper end portion 38 of the pole 12b.

It will be observed that in the assembled joint between the ledger pole 20 and the standard poles y12a and 12b the ledger pole 20 has the upper side of its external face disposed at the same horizontal level as the upper side of the transom 14b, which is Welded to the end portion 38 of the pole 12b. Alternatively the transom 14b may be disposed at a somewhat higher level so that when putlogs of a diameter equal to the transom 14b are laid on the ledgers crosswise thereof to span the space between the ledger pole 20 and the lower ledger pole of the frame unit 19 the upper faces of these putlogs are at the same level as the upper face of the transom 14b thereby avoiding any obstruction in lines of foot boards or planking placed on top of the putlogs to form the floor of each upper stage such as 10.

This may be contrived by welding the yledger pole 20 to the intermediate portion 32 of the tube 29 at a position somewhat below the centre of the length of this tube instead of at the centre of the length as illustrated in FIGURE 2.

Referring further to the spigot and socket elements 37 and 38 on the standard poles 12a and 12b themselves, these elements may be dimensione/d to provide a working clearance similar to that already referred to in the case of the spigot and socket elements which serve to connect the ledger pole 20 with the standard poles, and similarly the spigot element 37 may be formed by swaging down the end portion of the standard pole 12a, there being a frusto-conical or similar convergent connecting portion 39 between the spigot element 37 `and the remainder of this pole.

The outer face of this portion 39 thus acts as a stop face co-operating with the inner rim or corner defined by the intersection of the end face 40 of the pole 12b and the inner face of this pole.

In assembling the joint the lower frame incorporating the poles 12b and 13b is assumed to extend upwardly in a vertical plane and the ledger pole would then be placed in the position which it is required to occupy in the erected scalold structure, the spigot element 31 being entered into the socket element 27.

The ledger pole 20 is positively retained against upward displacement from this position by assembling the upper standard pole 12a including its attachment socket element 25 to engage over the upper end of the spigot element 30, at the same time the spigot element 37 of this pole entering the socket element 38 at the upper end of the pole 12b.

The pole 12a and its associated socket elements 25 and 26 tend to be pressed downwardly by .the weight of this pole and any components of the scaffold structure above it to retain the ledger 20 positively in position. This weight is transmitted to the pole 12b directly through thev intermediary of the frusto-conical portion 39 and the socket element 38. The complementary spigot and socket elements, of one co-operative pair may be so positioned or dimensioned longitudinally lrelatively to another such pair brought into and out of intertting relation at the same time that entry of the spigot elements into their associated socket elements is successive but overlapping in time and distance. This facilitatesy assembly.

Referring now to the similar joints made between the ledgers 19 and 23 and their associated poles 13a and 13b, it will be observed that in the case of the ledger 19 the pole 13b is provided wi- th socket elements 41 and 42 corresponding to the socket elements 27 and 28, while the pole- 13a is provided with socket elements 43 and 44 which correspond in principle with the socket elements 25 and 26 although they are disposed at a position further removed upwardly from the lower ends of the poles 6 13a, 13b vrespectively in consequence of the greater height afforded by the ledgers 19 and 23 than is the case for the individual ledger pole 20.

The ledger 19 is seen to comprise an upper ledger pole 45 and la lower ledger lpole 46 which are connected at their ends by upright - tubes 47 and 48 which have projecting end portions corresponding to the tube 29 in that each of these projecting portions terminates in a spigot element similar to the spigot elements 30 and 31. The frame unit forming the ledger 19 may be braced by bracing elements 49 and 50 welded to the upper and lower ledger poles 45 and 46 and to the upright tubes 47 and `48.

As in the case of the joint illustrated in FIGURE Z, the upper and lower standard poles 13a and 13b are separatable from each other lat a position just above the socket elements 41 and 42, the point of separation being indicated in FIGURE l by the broken lines 51. As alp ready described the lower ledger pole 46 may be welded to the uprights 47 and |48 so that its upper side is somewhat below the level at which the upper side of the transom 14b is situated for the reason hereinbefore set forth.

In the case of the ledger 23 which is constituted by a frame unit including upper and lower ledger poles 52 and 53 connected at their ends by upright tubes 54 and 55 and by bracing elements 56 and 57, the difference is that this frame unit is of double or approximately double the height of the frame unit 19 and that consequently socket elements 58 and 59 provided on the pole 13b which are equivalent to the socket elements 25 and 26 in FIGURE 2 are set at a still greater height from the lower end of the pole 13b than is the case in respect of the socket elements 43 and 44 with reference to the lower end of the pole 13a.

The socket elements 60 and 61 on the foot pole 13C areof course equivalent to the socket elements 27 and 28 -as shown in FIGURE 2, whilst the upright tubes 54 and 55 include end portions projecting. upwardly and downwardly from the upper and lower sides respectively of the upper and lower ledger poles 52 and V53 incorporated in this frame unit so as to engage respectively in associated socket elements.

In the case of both frame units 19 `and 23 the spigot elements provided thereon are retained in assembled relation with their associated socket elements on the standard by the compressive end loading of the standard poles which prevents the sub-divided parts 13ayand 13b of the poles being separated (a condition which is necessary to permit of disassembly of the frame units 19 and 23 from the standard poles). Y

In the case of the frame unit 23 the upper ledger pole 5-2 which typically may be disposed at a height of about 3 ft. 4 inches above the lower ledger pole 53, also performs the function of a handrail, whereas in the case of the upper stage incorporating the frame unit 19 of half the height a separate handrail 21 is provided,

The separate handrail 21 may be assembled with the Y standards 13 by the provision thereon of socket elements 62 in which downwardly projecting spigot elements extending from the lower side of the handrail 21 at each end can engage in a manner similar to the spigot element 31 as seen in FIGURE 2. The handrail 21 may be secured by the provision of socket elements. 64 which are slidable endwise along the standard poles 13a and can thus be raised temporarily to permit of assembly of the downi wardly projecting spigot elements of the handrail with the socket elements 62 and thereafter lowered over rupwardly projecting socket elements at the upper side ofthe 4handrail 21. Filhe socket element 64 may be retained in position positively for example by a cross pin extending through a sleeve portion which slides on the standard pole 13a or by the provision of any other suitable retaining means preferably positively acting.

Referring now to FIGURES the handrail 24 therein A rshown is provided with a spigot 71 projecting from the 7 underside of the handrail, this spigot being slotted or formed with a recess in which is pivoted a latch part 72.

The latch part 72 tends to descend to the position shown in FIGURE under its own weight so as to project laterally from the spigot 71, in which position it is retained by co-operative abutment means provided respectively on the spigot and on the latch such for example as a shoulder 73 on the former which engages with the upper edge of the latter.

On inserting the spigot downwardly through the associated socket element 63 provided on the standard pole 12b the latch is automatically displaced into the slot or recess until its outer end 74 has been moved below the lower end of the socket element 63, whereupon the latch 72 automatically takes up the position shown in FIGURE 5 and positively prevents withdrawal of the spigot from the socket element 63.

As a possible alternative illustrated in the case of the handrail 22 the socket elements 65 provided on the poles 12a may be equipped with clamping devices for example in the form of thumb screws 66.

It will be understood that it is not essential that the standards 12 and 13 should be constituted by parts of the frame units lllt) and 11 as in the construction illustrated in FIGURE l. They may be in the form of individual poles sub-divided into separate standard poles such as 12a and 12b and 13a and 13b.

In this case the standards 12 and 13 will require to be connected by transoms which are structurally separate from the standard poles themselves, and connection between these transoms and the poles may be effected in the same manner as that adopted for the individual ledger pole illustrated in FIGURE 2.

Referring now to the construction illustrated in FIG- URE 6 component parts corresponding to those illustrated in FIGURE 2 have been designated by like numerals of reference.

The essential diiference between this construction and ythat illustrated in FIGURE 2 is that whereas in the former construction the standard poles 12a and 12b intertit directly with each other lengthwise of these poles, they do so in the construction illustrated in FIGURE 6 through the intermediary of a further attachment element 7S which is welded or otherwise fixed at one end of a transom member 76 which is equivalent to the transom 14b incorporated in the end frames of the structure illustrated in FIGURE l but which in fact is structurally separate from the standard poles 12a and 12b.

It will be understood that an attachment element similar to 75 would be provided at both ends of the transom member 76 so that it can be assembled in intertting relation with the poles 13a and 13b as well as 12a and 12b.

Furthermore, the transom member 76 is preferably welded or otherwise fixed near the upper end of the attachment element 75 so that its upper Side will lie on the same level as the upper sides of the putlogs laid transversely of the ledger members 20 and resting thereon.

The ledger member 20 instead of being in the form of a single length of tube may be reinforced by the addition of bracing members 77 and 78 so as to form a ledger IIUSS.

In a further form of standard pole illustrated in FIG- URES 3 and 4 these may be provided with a cluster of socket elements at each level at which an individual ledger pole or lower ledger pole of a ledger frame unit is required to be connected to the standard, the cluster including the socket element for the connection of the transom pole such as 14a or 14b. Bracing may be provided between the transom and the spigot element which rfor this purpose would be somewhat longer than is necessary merely for intertting with the socket element.

A typical cluster of socket elements is illustrated in FIGURE 3 representing the upper end portion of the standard pole 12b, the socket elements 27 and 28 being indicated as occupying positions at the end of a reference 8 diameter drawn through the standard pole 12b, and the further socket element 67 being disposed on a diameter at right angles to the reference diameter.

Each of these socket elements may be permanently united with the pole 12b by welding as indicated at 68 and 69 in the case of the socket elements 27 and 28 and 70 in the case of the socket elements 67.

As previously mentioned the end faces of these socket elements adjacent to their mouths, that is to say the upper end faces may be notched or slotted if desired to provide a means for keying the spigot elements entering them against relative rotation about the axis of the socket clement concerned.

It will be understood that the `frame units 19 and 23 and possibly ledger members such as 20 or ledger trusses as illustrated in FIGURE 6 may be provided with an upwardly extending fence of openwork form constituting a toe guard, such fence being dosposed in the case of the frame units immediately above the lower ledger pole 20 and 53 as the case may be. The fence may be formed from one or more pieces of wire mesh welded or otherwise suitably secured to the frame unit or truss as the case may be. Where a toe guard is provided in association with a single ledger pole such as 20 the latter may include upwardly projecting lengths of tube of a height equal or aproximately equal to the height of the toe guard to which the wire mesh may be welded, these lengths of -tube being themselves welded to the upper side of the ledger pole.

In any of these constructions the member which constitutes the toe guard may be secured to the outer side lface of the frame, truss or pole constituting the ledger member so that it does not interfere with the laying of putlogs or other platform means on the upper sides of the ledger members.

A particularly convenient form of platform means which may be provided comprises a frame composed of a pair of spaced parallel tubular members of the kind usually employed as putlogs, these being connected together by girders situated at their undersides, conveniently such girders being of 'angle or channel section and welded to the putlog tubes. The girders would extend parallel to the ledger members and be spaced apart to locate against the inner sides of the ledger members thereby preventing the platform member from shifting from side to side and also from becoming skewed by rotation in a horizontal plane.

As a possible alternative to the arrangements adopted in the scaffold structure ilustrated in FIGURE l it will be understood that each of the ledgers may be connected at one of its ends only to the adjacent standard by the means hereinbefore specifically described and illustrated, namely, attachment elements on separate standard poles which `are offset laterally from such standard poles and which intert longitudinally of the standard poles with complementary attachment elements on the ledger. At the other end, such ledger 20 may break in to the standard situated thereat the two parts of which lare designated by numerals 12a and 12b. For example in the case of the ledger 20 at one end thereof, ythe upright tube 29 would lie alongside its associated standard poles `12a and 12b and be connected thereto in the manner illustrated in FIGURE 2 but the upright tube 29 at the other end of the ledger 20 would in effect be utilised as part of a standard by omitting the attachment elements 25 and 27, or alternatively utilising them for purposes of attachment of further horizontal members, and the spigot elements at the ends of the upright tube 29 would then interit longitudinally with the presented upper end portion of the pole 12b and with the downwardly presented lower end portion of that part of the standard pole 12a situated above the ledger 20. The part of the standard pole 12a which in FIGURE l is shown yalongside the upright tube 29 would be omitted.

Attachment elements 26 and 28 would still be provided.

It will be understood that if desired, a similar arrangement may be adopted in respect of each of the frame units 19 land 23.

It will be apparent that in this modilied arrangement the ledgers are kept in place by the weight of the structure situated in each case above them acting downwardly. This may be applied at the end at which the ledger breaks in yto the standard as well as at the end at which attachment elements offset vfrom the separate standard poles are provided to interiit with the complementary attachment elements of lthe ledger.

In the modified construction illustrated in FIGURE 7 a transom 20 (which is the equivalent of the transom 14b i-n FIGURE l but consists of a single cross tube only instead of being formed as part of a frame) is provided at each end with attachment elements, comprising an upwardly projecting spigot 80 and downwardly projecting socket 81 yfor interiitting respectively with the socket portion afforded at the lower end of the standard pole 12a and with a spigot portion afforded by the upwardly presented end portion of the standard pole 12b.

The standard pole 12a is provided with socket elements 25 and 26 and the pole 12b is provided with socket elements 27 and 28, these socket elements -interttting with spigot elements at the ends of tie members in the -form of horizontal ledgers 83 and 82.

The socket element 81 of the transom 20 has secured thereto an element 85 extending transversely of the pl-ane occupied by the transom 20 and its associated attachment elements, the element 85 conveniently being in the form of an angle section bar secured to the socket element 81.

It will be evident from the drawing that the end portions of the element 85 are disposed closley adjacent to the inner side faces of the spigot elements 88 and 89 of the ledgers 83 and 82, and thereby serve to locate the, transom 18 accurately in right angled relation with these ledgers and thereby stiten the scaffold structure as a whole against deflection about the axis of the standard poles 12a .and '12b.

What we claim then is:

1. In a scaold structure comprising standards formed of standard poles having at each pair of adjoining ends respective portions interittting with each other, and tie members extending transversely between said standards; the provision of means for connecting said tie members to said standards comprising, an attachment element on one of -said poles offset radially from the axis of said pole, a complementary attachment element on the tie member and interlitting with the iirst said attachment element, one of said attachment elements having a guide face defining an entry for the other of said attachment elements extending lengthwise of said pole to deflne an assembly and withdrawal path for said complementary attachment element, a retaining element on another of said poles successively positioned to the first said pole in that standard which includes both of them, said retaining element being disposed in the Withdrawal path of said complementary attachment element thereby positively obstructing withdrawal.

2. In a scaiiold structure comprising standards formed of standard poles having at each pair of adjoining ends respective portions interiitting with each other, and tie members extenidng transversely between said standards; the provision of means for connecting said tie members to said standards comprising, attachment elements on respective successively positioned poles in the standard, said attachment elements being oiset radially from the axis of said standard, and complementary attachment elements on the tie member spaced apart and projecting in opposite directions lengthwise of said standard and interlitting slidably with said attachment elements on the poles thereof, whereby the upper of said poles and its at- Itachment element positively prevents Withdrawal fl'Om the other attachment element of the lower of said poles of the tie member and complementary attachment element interltting therewith.

3. In a scalold structure comprising standards `formed of standard poles having at each pair of adjoining ends lrespective portions interfitting with each other, and tie members extending transversely between said standards; the provision of means for connecting said tie members to said standards comprising, attachment elements on respective successively positioned poles in the standard, said attachment elements being olset radially from the axis of said standard, and spaced apart 'from each other lengthwise of the standard by a substantial distance, and complementary attachment elements on the tie member, the latter comprising a frame of a height approximating to saidv substantial distance, said complementary attachment elements being disposed on said -frame at its upper and lower ends respectively, projecting upwardly and downwardly respectively with respect to said frame and l interlitting slidably with said attachment elements on said poles, whereby the upper of said poles and its attachment element positively prevents withdrawal from the other attachment element of the lower of said poles of the tie member and complementary attachment element interitting therewith.

4. In a scalold structure comprising standards formed of standard poles having at each pair of adjoining ends respective portions interlitting with each other, and tie members extending transversely between said standards; the provision of means for connecting said tie members to saidstandards comprising, attachment elements on respective successively positioned poles in the standard, said attachment elements being oiset radially from the axis of said standard, one at least of them being disposed at a position spaced by a substantial distance from that end of its pole which interts 4with the end of the other of said poles and from the other of said attachment elements, and complementary attachment elements on the tie member the latter comprising a frame of a height approximating -to said substantial distance, said complementary attachment elements being disposed on said frame at its upper and lower ends respectively, projecting upwardly and downwardly respectively with respect to said frame and intertting slidably wit-h said attachment elements on said poles, whereby the upper of said poles and its attachment element positively prevents withdrawal from the other attachment element of the lower of said poles of the tie member and complementary attachment element intertting therewith.

5. In a scalold structure comprising standards formed of standard poles having at each painof adjoining ends respective portions intertitting with each other, and tie members extending transversely between said standards; upper and lower socket elements on successively positioned upper and lower poles respectively in the standard, said socket elements comprising tubular elements fixed to the sides of said poles the lower of said socket elements having an upwardly presented entry and the upper of said socket elements having a downwardly presented entry upper and lower spigot elements on the tie member interiit-ting respectively with said upper and lower socket elements, and -abutment means at the lower and upper ends of said upper and lower spigot elements spaced apart by a distance such that engagement by lower and upper ends of said upper and lower socket elements retains the tie member posi-tively in assembled position in the scaffold structure.

6. In a scafford structure comprising standards and tie members extending transversely between said standards; the combination of separate poles comprising said standards, spigot and socket pole portions on successively positioned poles in each standard and interiitting with each other, upper and lower socket elements on said successively positioned poles txed to and offset laterally from said poles, said socket elements being spaced apart lengthwise of the standard and one at least of each pair of upper and lower socket elements being spaced length-` wise of the standard from said intertting spigot and socket pole portions, upper and lower spigot elements on each tie member projecting upwardly and downwardly at one end at least thereof and intertting with said upper and lower socket elements, yand abutment means at the lower and upper ends of said upper and lower spigot elements spaced apart by a distance such that engagement by lower and upper ends of said upper and lower socket elements retains the tie member positively in assembled position in the scaffold structure.

7. In a scaffold structure comprising standards and tie members extending transversely between said standards; the combination of separate poles comprising said standards, spigot and socket pole portions on successively positioned poles in each standard and intertting with each other, upper and Ilower socket elements on said successively positioned poles fixed to and offset laterally from said poles, said socket elements being spaced apart lengthwise of the standard by a substantial distance and one at least of each pairpof upper and lower socket elements being spaced lengthwise of the standard from said intertting spigot and socket pole portions, frames comprising said tie members and of a height approximating to said substantial distance, and upper and lower spigot elements fixed to said frames at each end thereof projecting upwardly and downwardly respectively therefrom and intertting with said upper and lower socket elements.

References Cited in the tile of this patent UNITED STATES PATENTS 1,880,125 Ewing sept. 27, 1932 2,559,469 Scheidemantle July 3, 1951 2,771,324 Ryder Nov. 20, 1956 FOREIGN PATENTS 61,943 France Dec. 15, 1954

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