US2424115A

US2424115A - Elevating support for scaffold platforms

Info

Publication number: US2424115A
Application number: US635090A
Authority: US
Inventors: Powell Archibald Douglas
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-12-14
Filing date: 1945-12-14
Publication date: 1947-07-15
Anticipated expiration: 1964-07-15

Description

I July 15, 1947.

A. D. POWELL 2,424,115 ELEVATING SUPPORT FOR SCAFFOLD PLATFORMS Filed Dec. 14, 1945 ATTORNEK Patented July 15, 1947 ELEVATIN G SUPPORT FOR SCAFFOLD PLATFORMS Archibald Douglas Powell, Braintree, England Application December 14, 1945, Serial No. 635,090

' In Great Britain December 14, 1944 '11 Claims. 1

This invention has reference to improvements in and relating to apparatus for use in conjunction with tubular steel scaffoldin for supporting a working platform and preferably for raising it as the work proceeds.

One feature of the invention resides in the provision of such apparatus comprising a guide adapted to slide along the tubular steel standards of scaffolding and retaining means adapted to support the guide on the standard on which it slides by gripping the said standard and being adapted to yield freely to upwardly acting forces, the guide being adapted to be secured to the ledgers of the scaliolding. The retaining means is preferably located beneath the guide, the guide normally thrusting onto the said means; and the retaining means is preferably adapted to be made temporarily inoperative with respect to the standard so that the guide can, when desired, be freely lowered down the standard.

A further feature of the invention resides in the provision of apparatus comprising the guide and retaining means and jacking mean adapted to scale the standard, said jacking means in scaling the standard being arranged to raise the guide and the retaining means.

Another feature of the invention resides in the provision of apparatus comprising the guide and retaining means and jacking-retainin means, said jacking-retaining means being adapted when not actually scaling the standard, to co-operate with the first-mentioned retaining means to hold the guide against unintentional descent down the standard.

Apparatus according to the invention will now be described with reference to the accompanying drawings wherein:

Fig. 1 is a face view of the apparatus and Fig. 2 is a side View thereof, the retaining means being shown in operative condition in these two Figs;

Fig. 3 is a face view of the lower part of the said apparatus but the retaining means is in its inoperative condition; and

Figs. 4 and 5 are face views of the lower part of apparatus modified as to the connection of the guide to the retaining means and as to the means for selectively rendering the retaining means operative or inoperative, the retaining means being in operative condition in Fig. 4 and in inoperative condition in Fig. 5. 1 The apparatus shown in Figs. 1, 2 and 3 comprises a guide I, a retaining means 2 and a jacking means 3. the guide bein suspended from the jacking means and the retaining means being mounted on the guide.

The guide comprises a tube 4 which is a sliding fit on the standards as 5 with which the guide is to be used. At the top of'the tube is a horizontal cross plate 6 having holes near its ends for the reception of the lower parts of suspension pins 1 or the like depending from the jacking means, the axes of the pins and the axis of the tube being in substantially the same vertical plane. At the bottom of the tube is a pair of depending lugs 8 for the reception of the ends of the spindle or trunnions on which a g pp plate 9 of tipping plate type tilts, said plate bein so positioned beneath the tube that its two opposite

angular gripping jaws

9', 9, which jaws are rigid, will engage diagonally opposite zones of the standard 5. The upper part of the tube is a tolerance fit on the standard Whilst the bore of the tube beneath the tolerance fitting part is a loose fit for a reason which Will be explained hereinafter.

One lug 8 is on a plate In fixed g" Welded) to the lower end of the tube at one side thereof. The other lug is on a plate ll fixed (e. g., welded) to the tube for substantially the whole length of the latter and at the side opposite to that to which the plate It is fixed. The plate II is wider at its middle than it is at its ends. The widest part of the plate is bored near its sides, about midway of its ends, for the reception of the outer ends of the legs of U-bolts l2 by means of which the guide is secured to a ledger 13. The greatest width of the plate is such that the bolts are spaced well apart as shown in order that good lateral support is ensured between the guide and the ledger and the axis of the tube is firmly kept substantially at right angles to the axis of the ledger. A cross tree instead of the plate may be secured to the tube 4 and in this case a plate similar to the plate I!) is provided opposite the plate Ill for supporting the trunnion of the gripping plate. The cross tree will have a length comparable with the width of the plate H for the same purpose. 7

A compression spring H (but it may be a weight) is incorporated in the retaining means for pressing the jaws of the gripping plate into close engagement with the standard 5. The spring I4 i locatedbetween the tube 4 and an arm I5 upstanding from the gripping plate; and

an arcuate guide and retaining bar it rigid with the arm l5 enters the spring for art of its length.

Means comprising a cam and lever device is provided'for holding the gripping jaws idle during lowerin periods. The cam profile, indicated at H, is formed on the arm I 5 and the lever, indicated at 18, which is pivotally mounted on the plates in and H has a roller or pin l9 which, by contact with the cam profile when the lever is moved upwardly,'displaces the cam and, therefore, the gripping plate to the positions shown in Fig. 3. The resulting movement of the gripping plate takes place against the action of the spring or weight and causes the jaws to assume the idle position (Fig. 3) with respect to the standard. The tip of the arm and the outer end of the bar 16 collectively form a depression which receives the roller when the jaws are idle and so causes the roller to retain the jaws in this condition until the roller is intentionally freed from them. The arm i is recessed at 20 to provide a stop limiting the movement of the roller in the jaw-freeing direction.

The jacking means comprises a slide 2| adapted to be forced up the standard in steps by means of a lever 22. The lever has a forked end which straddles the slide 2| and is pivotally secured to the latter near the end of the fork. The fulcrum 23 of the lever, which fulcrum comprises two stubs rigid with the limbs of the fork, is hingedly suspended from a tipping plate 24 by means of a pair of link 25. The tipping plate 24 having two opposite, rigid angular jaws 24', 24 is normally held in gripping relation to the standard by means of a spring such as the leaf spring '26 secured at one end to the plate and at the other end to the links at a zone near the bottoms thereof.

When the lever 22- is depressed the slide is forced up the standard and pulls the guide with it. The guide pulls the retaining means upwards, the gripping plate 9 slipping up the standard. When the lever is raised the retainin means takes the load and the gripping plate of th jacking means slides up the standard to its new position, and so on, the upstroke of the lever being limited by a stop 21 provided on the suspension links 25.

It is desirable to limit the upstroke of the lever (the downstroke is limited by engagement of the yoke of the fork on the lever with the slide) but the primary reason for providing the stop 21 is to enable the gripping plate 24 to co-operate with the plate 9 in holding the apparatus against unwanted sliding movement downwards. When the yoke bears against the stop the connection between the plate 24 and the guide is, so far as "downwardly acting forces on the guide are concerned, solid. Therefore, the gripping plate '24 is able to assist the holding action of the plate '9 as previously stated. This is a'hig'hly desirable feature when it is borne in mind that the platform carries workmen.

When it is desired tolower the guide the lever 18 of the retaining means is moved to the position in which it renders the gripping plate idle and the gripping plate of the jacking means is rendered idle by a workman pulling on a release cord or the like (not shown) attached to the latter plate in such a manner that the pu1l moves it to an idle position. The Whole guide is then free to slide down the standard-and the'rate of descent is controlled from ground level by a cable which has one of its ends attached to the guide and which passes over a pulley at the top of the standard and thence to the ground. The plate 24 maybe provided with a lug at that end furthest from the'links to which lug 'the'rele'ase cord can be attached.

When the'retaining means is rendered idle the whole of the weight of and on the guide 'is'taken by the gripping plate 24 until this plate is 'also rendered idle.

The standards of scaffolding on which a platform is to be mounted are each provided with a supporting and lifting apparatus according to the invention, the guides being securedto ledgers and the ledgers supporting putlogs as 28 and planks. Usually six apparatuses will be arranged tosupport and raise one platform. For raising, a

man at each end of the platform will simultaneously make a few strokes with the levers of the at the middle of the platform and so on until the required platform height is attained. The whole assembly is flexible and is easily able to accommodate the inequalities of lifting that arise; and it is in order not to impair this flexibility and even to enhance it that the tops only of the guide tubes are a tolerance fit on the standards, whilst the rest of the tubes are appreciably loose. This looseness does not, however, result in general loosenes of the assembly as immediately lifting ceases the retaining means of each apparatus nullifies or cancels out the looseness.

In order also not to impair the flexibility of the assembly each guide is attached to its jacking means by a flexible suspension comprising a cross plate 29 at the bottom of the jacking slide, the cross plate 6 at the top of the guide and conical or spherical seating surfaces on the ends of the pins 1 which ends take into recesses in the cross plates, the top of the gu'idebeing spaced from the slide by a short distance as shown.

The cross plate 29 seats on a part-spherical surface at the top of a flange 30 at the base of the slide-once again in order not to impair flexibility and, in addition, to enable'the jacking means to be swung as a whole on the standard so that the'jacking lever can be moved clear of any obstruction that may be encountered,

In Figs. 4 and 5 the guide is suspended from the trunnions of the gripping plate 9 by means 'of links as 3'! which lie adjacent to the outer'faces of the plates l0 and II. Thebottoms of thelinks are hinged to the plates near the bottoms of the latter; the upper ends of the links receive the outer ends of the trunnions on the plate 9, the plates 1 El and I I being slotted to permit of a small amount of side play of the trunnions in relation to the plates. A spring toggle 32 when upset as in Fig. '4 resiliently urges the plate 9 into the operative position shown and when upset as in Fig. 5 holds the plate in the inoperative position shown. The operating means for the toggle consists of a trigger 33 rigid with the upper one of the toggle links. The said upper link has lateral flats 34 which, by pressing on the underface of the plate 9 to one side or the other of the trunnion axis, appropriately turn the plate 9 on its trunnions.

What I claim is: g

1. Apparatus for raising and supporting working platforms used in building and'the like. said apparatus being for use in conjunction with tubular steel scaffolding standards, comprising a guide which can slide along a tubular steel scaffolding standard, guide retaining means which grips the standard on which the guide slides, said retaining means being resistant to downward thrust but yieldable to upward thrust jacking means which scales the standard on which the guide slides, a swiveljoint,said swivel joint connecting the jacking 'means to the guide, and means associated with the guide for securing a, working platform thereto.

2. Apparatus for raising and supporting workingplatforms usedin building and the like, said apparatus being for use in conjunction with tubular steel scaffolding standards, comprising a guide which can slide alonga tubular steel scaffolding standard, guide retaining means which grips thestandard on which the guide slides, said retaining means being resistant to downward thrust but yieldable to upward thrust, jacking means which scales the standard on which the guide slides, said jacking means being located above the guide, a slide comprised in the jacking means, said slide being operatively connected with the jacking means to move along the standard in the jacking operation, a flexible suspension between the slide and the guide, and means associated with the guide for securing a working platform thereto.

3. The combination with a tubular steel scaffolding standard of platform-supporting and raising apparatus comprising a guide, said guide being slidable along the standard, guide retaining means comprising a tipping plate which grips the said standard, jacking means operatively associated with the guide, said jacking means comprising a tipping plate which scales the standard, the tipping plate of said retaining means having two rigid angular jaws and the tipping plate of said jacking means having two rigid angular jaws which jaws grip the standard when downwardly acting forces are applied to their respective plates but yield upwards to upwardly acting forces, and means associated with the guide for securing a working platform thereto.

4. The combination with a tubular steel scaffolding standard of platform-supporting and raising apparatus comprising a, guide, said guide being slidable along the standard, guide retaining means comprising a tipping plate which grips the said standard, jackin means operatively associated with the guide, said jacking mean comprising a tipping plate which scales the standard, the tipping plate of said retaining means having two rigid angular jaws and the tipping plate of said jackin means having two rigid angular jaws which jaws grip the standard when downwardly acting forces are applied to their respective plates but yield upwards to upwardly acting forces, means associated with the guide for securing a working platform thereto, and means carried by said guide for releasably securing the tipping plate of the guide retaining means in inoperative condition with respect to the standard.

5. The combination with a tubular steel scaffolding standard of platform-supporting and raising apparatus comprising a guide, said guide being slidable along the standard, guide retaining means comprising a tipping plate which grips the said standard, jacking means comprising a tipping plate which scales the standard, the tipping plate of said retaining means having two rigid angular jaws and the tipping plate of said jacking means having two rigid angular jaws which jaws grip the standard when downwardly acting forces are applied to their respective plates but yield upwards to upwardly actin forces, a swivel joint connecting the jacking means to the guide and means associated with the guide for securing a working platform thereto.

6. A combination according to claim 3, com prising a guide embracing the standard, the upper part of the guide embracing the said standard more closely than does the lower part thereof and said guide retaining means being located at the lower part of the guide and said jacking means being located at the upper part of the guide.

7. A combination according to claim 3, comprising a guide embracing the standard, the upper part of the guide embracing the said standard more closely than does the lower part thereof and said guide retaining means being located at the lower part of the guide and said jacking means being located at the upper part of the guide, a slide comprised in the jacking means, said slide being operatively connected to the jacking means to move along the standard in the jacking operation, and a flexible suspension between the slide and the guide.

8. In a combination according to claim 3, a cam and a lever operatively associated with the said cam for rendering the tipping plate of the retaining means temporarily inoperative with respect to the standard.

9. In a combination according to claim 3, a spring toggle for rendering the tipping plate of the retaining means temporarily inoperative with respect to the standard.

10. The combination with a tubular steel scaffolding standard of platform supporting and raising apparatus comprising a guide, said guide comprising a tube arranged around the standard in sliding relation thereto and a cross member rigid with said tube, securing means for attaching a working platform to said cross member, guide retaining means comprising a tipping plate which grips the said standard, jacking means operatively associated with the guide, said jacking means comprisin a tippin plate which scales the standard, the tipping plate of said retaining means having two rigid angular jaws and the tipping plate of said jacking means having two rigid angular jaws which jaws grip the standard when downwardly acting forces are applied to their respective plates but yield upwards to upwardly acting forces, and means for biassing said gripping plates into gripping position relative to the standard in the sense resisting downward movement therealong.

11. The combination with a tubular steel scaffolding standard of platform-supporting and raising apparatus comprising a guide, said guide being slidable along the standard, guide retaining means comprising a tipping plate resistant to downward thrust but yieldable to upward thrust, jacking means which scales the standard, said jacking means being operatively associated with the guide, means carried by said guide for releasably securing the tipping plate of the guideretaining means in inoperative condition with respect to the standard, and means associated with the guide for securing a working platform thereto.

ARCHIBALD DOUGLAS POWELL.

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

UNITED STATES PATENTS Number Name Date 588,982 Gray Aug. 31, 1897 664,508 Smith et al Dec. 25, 1900 1,195,976 Chesebro Aug. 29, 1916 1,366,487 Pitou Jan. 25, 1921 1,416,296 Hoitsma May 16, 1922 1,441,806 Hoitsma Jan, 9, 1923 2,007,480 Schernekau July 9, 1935 2,216,912 Hoitsma Oct, 8, 1940