Apparatus for use in buildings

An attachment for a builder's prop, scaffold pole of the like comprising a stem screw-threaded along at least a portion of its length and provided at one end with a top bearer plate, an intermediate bearer plate being mounted on a tubular sleeve which is slidable along the stem and adjustably positionable thereon by means of a nut engaging the screw thread, means being provided for preventing rotation of the sleeve around the stem as the nut is rotated to alter the position of the sleeve along the length of the stem.

This invention relates to formwork for concrete and is an improvement or a 
modification of the invention forming the subject of our British Pat. No. 
1,427,518. 
Concrete floors and the like may well take a considerable time -- a number 
of weeks for example -- before they are fully cured, during which time 
they need to be supported. It is desirable to be able to re-use equipment 
as quickly as possible and this has tended to lead to an undesirable 
practice of dismantling the formwork system of shutters and props from 
only partially cured concrete e.g. after several days, removing the 
shutters for re-use and replacing the props to support the floor until the 
concrete has properly cured. This naturally leads to undesirable stresses 
in the concrete before it is properly cured whilst the props are removed 
and may lead to further undesirable stresses due to over tightening the 
props on replacement. 
British Pat. No. 1,427,518 is directed to a prop attachment for supporting 
formwork shuttering comprising a stem screw-threaded along at least a 
portion of its length and provided at one end with a top transverse bearer 
plate, intermediate and lower transverse bear plates being mounted on and 
slidable together along the stem and being adjustably positionable thereon 
by means of a nut engaging with the screw thread. The lower bearer plate 
is preferably slidably mounted on the stem by means of a tubular sleeve. 
Use of such an attachment on a prop enables shuttering members supported by 
the bearer plates to be lowered after preliminary curing of a concrete 
slab cast over the shuttering, and removed for use elsewhere leaving the 
partially cured concrete still supported at intervals, by the top bearer 
plates of the props. 
Such a prop attachment is improved or modified in accordance with this 
invention by the presence of means (e.g. a pin sliding in a slot) to 
prevent rotation of the sleeve around the stem. Further the presence of 
the intermediate bearer plate is no longer essential. 
The prop to which the attachment may be secured in use, is preferably so 
made as to enable its length to be adjusted. For example, it may be in two 
sections, one slidable within the other, the outer section (which is 
normally the lower positioned section in use) being provided with a number 
of holes spaced along its length, the overall length of the prop being set 
by securing a pin in a desired one of the holes so that it passes also 
through a hole in the inner or upper section or so that the lower end of 
the inner section abuts the pin. 
In order to allow fine adjustment of the length of the prop and hence of 
the height of the upper bearer plate from the ground the screw threaded 
portion of the upper attachment may extend slidably into a socket in the 
upper end of the prop (which may be tubular), a second nut, below the 
first, bearing on the upper end of the prop. 
Alternatively the prop may be provided with screw length-adjusting means in 
which case it and the attachment may be flange coupled by means of 
respective plates welded to the ends of the members, the plates being 
bolted together. 
The uppermost position of the lower bearer plate may be limited for example 
by a collar. 
In use, shuttering is supported by the lower bearer plate and, after 
preliminary curing of the concrete, the shuttering may be removed by 
lowering the lower bearer plate leaving the partially cured floor 
supported by the top bearer plate. 
It will be appreciated that the attachment of this invention could be used 
to support members other than those for formwork shuttering and indeed may 
itself be supported by a fixed support or stut e.g. a scaffold member and 
not only by the adjustable props. For example, a framework might support a 
plurality of separate platforms or paths over a site between which one or 
more bridges are occasionally required. The requisite number of 
attachments may be incorporated in or supported by, the framework and the 
bridge supported on the transverse bearer plates. Such a bridge may then 
easily assembled and dismantled at a chosen location without the framework 
itself needing to be adjusted, merely by lowering the transverse bearing 
plates.

Referring to FIGS. 1 and 2 of the drawing the prop attachment comprises a 
stem 2 threaded over its lower portion 4 and provided with a top 
transverse bearer plate 6 at its upper end. The lower end of the stem is 
provided with a fixing plate 8 to be bolted to the top plate of a standard 
builders adjustable prop. 
A lower transverse bearer plate 10 is carried by a sleeve 12 slidably 
mounted on the stem 2 and resting on the upper surface of a nut 14 which 
is screw-threadedly engaged with the screw portion 4 of the stem. The 
position of the lower bearer plate 10 may be adjusted relative to the top 
bearer plate 6 by turning the nut 14. 
A collar 16 is welded to the stem 2 above the bearer plate 10 to limit the 
upward movement of the plate. 
A pin 18 extends out from the stem 2 and engages in longitudinal slots 20 
formed in each side of the sleeve 12 the arrangement being such that the 
sleeve 12 can rise and fall relatively to the stem 2 on adjustment of the 
nut 14, but cannot turn relatively to the stem. 
The nut 14 is formed with a recess 21 in which the lower end of the sleeve 
12, engages. This recess helps to align the sleeve with the stem 2 and 
helps to prevent the sleeve and hence the bearer plate 10 from wobbling. 
In use the overall height of a series of builders' props to which the 
attachment is secured is adjusted to bring the top bearer plates 6 to 
substantially the height of the underside of the floor or the like to be 
cast. Support beams (not shown) are laid between pairs of adjacent lower 
bearer plates 10 and shuttering panels are laid across between pairs of 
beams. The nuts 14 are then adjusted to bring the top of the panels level 
with the top support plates 6. 
Concrete may then be poured in the usual manner over the panels and over 
the plates 6. When the concrete is partially cured, the nuts 14 may be 
screwed downwardly on the screwed stem portions 4 so as to lower the 
bearer plates 10 and the beams and shuttering panels supported thereby. 
The beams and shuttering panels may then be removed for re-use leaving the 
props in position with the top bearer plates supporting the partially cast 
floor. 
FIG. 3 shows attachments in accordance with this invention when used with a 
fixed support frame as compared with FIGS. 1 and 2 which show the 
attachment connected to a single adjustable prop. 
Two prefabricated framework supports are generally indicated at 22 and 24 
in FIG. 3 each being mounted on ajustable screw-jack feet 26. Attachments, 
generally indicated at 28 and similar to those described with reference to 
FIGS. 1 and 2 are mounted on the top of each of the vertical members 30 of 
the framework. 
Each framework support comprises four upright tubes 30 connected by cross 
braces 32 so that each support is in a form of a self-sustaining 
rectangular pillar. Each tube member 30 has a screwed rod 34 engaged in 
its open upper end, each screw 34 being provided with a nut 36 which rests 
on the top of the tube 30 and acts to support the rod 34 on the framework. 
The top of each screwed rod 34 is provided with a plate 38 to which the 
fixing plate 8 of each attachment 28 is secured by conventional bolts (not 
shown). 
The height of each top bearer plate 6 of the attachments is adjusted by 
screwing nut 36 up and down the screw 34 until the plane of the bearer 
plates defines the required upper support surface. The transverse bearer 
plates 10 of the attachment which are movable with respect to the head 
plate 6 and support plate 8 act as support surfaces to hold a temporary 
structure. 
Structural panels 40 are supported by beams 42 which are in turn supported 
on the bearer plates 10. A concrete floor may then be cast over the panel 
40 as described hereinbefore with reference to FIGS. 1 and 2. 
The space between the separate self-sustaining framework supports 22 and 24 
may be bridged by a further beam 44 which is also supported on the plates 
10 of adjacent attachments on the two framework structures and the beams 
44 may either support additional panels 40 so that a complete floor is 
cast over the two framework supports and over the space there-between or 
alternatively the beam 44 may support a temporary bridge or gangway 
linking the two structures e.g. to facilitate delivery of the concrete. 
The gangway or bridge may then be dismantled after the concrete has been 
delivered by dropping the support plates 10 leaving an unimpeded passage 
between the two framework supports. 
It will be appreciated that the surface or surfaces defined by the top 
plates of the attachments may be other than horizontal. 
It will also be appreciated that the temporary bridge beam 44 could be 
supported by attachments in accordance with the invention which are 
themselves connected to and supported by, a solid support structure rather 
than connected to the framework illustrated. 
As a further example the attachments of the invention may be secured not to 
a framework support as illustrated in FIG. 3 having adjustable height but 
may be secured directly to scaffold poles or the like forming part of any 
desired structure. The attachments will again enable a temporary structure 
to be supported and later removed whilst the main support structure 
remains in position.