GB2271802A

GB2271802A - "A scaffolding prop"

Info

Publication number: GB2271802A
Application number: GB9222487A
Authority: GB
Inventors: Demetrios Georgio Papadopoulos
Original assignee: SGB Holdings Ltd
Current assignee: SGB Holdings Ltd
Priority date: 1992-10-26
Filing date: 1992-10-26
Publication date: 1994-04-27
Anticipated expiration: 2012-10-26
Also published as: GB2271802B; GB9222487D0

Abstract

A telescopic prop comprises an inner element (1) having at least one transverse bore (2) which is telescopically received within an outer tubular element (3) which has a pair of opposed apertures (4) of elongate axial form and exterior threading (5). A collar (6) is threadedly engaged with the exterior threading. A pin (12) extends through the passage-way, and through the opposed apertures, the pin resting on top of the collar. The portion of the pin resting on the collar is rotatable about its axis, and that portion of the pin is provided with recesses (15) aligned with the parts of the collar on which the pin rests. The pin is rotatable to move the pin from a first position in which the collar engages the exterior of the pin to an alternate position in which the collar engages the recesses formed in the pin. Thus, the inner element can be dropped by a short distance relieving the pressure exerted on the telescopic prop. <IMAGE>

Description

DESCRIPTION OF INVENTION "IMPROVEMENTS IN OR RELATING TO A SCAFFOLDING PROP" THE PRESENT INVENTION relates to a scaffolding prop.

It has been proposed to provide a scaffolding prop of telescopic form. The prop consists of an inner element in the form of a tube that is slidable telescopically within an outer tube. The inner tube is provided with a plurality of diametrically opposed apertures, which effectively define through-passages extending across the inner element and the outer tube is provided with two opposed apertures, of elongate form, the apertures extending axially of the tube. The outer tube is provided with external threading and carries a collar which engages the threading. A pin is provided which can pass through the apertures int he outer tube, and a pair of opposed apertures in the inner element.

In order to assemble the prop the inner element is slid into the outer tube until a selected pair of diametrically opposed apertures in the inner tube are aligned with the diametrically opposed apertures in the outer tube. A pin is then passed through the aligned apertures, the end of the pin projection beyond the outer tube. The collar, mounted on the outer tube, is then rotated so that the collar is driven upwardly to engage the projecting ends of the pin. The collar may then be turned further, thus driving the pin, and the inner tube, upwardly until the prop has precisely the required length.

A prop of this type may be used to support falsework or forms, used when forming a ceiling/floor structure for poured concrete. When the concrete has been poured into the falsework and/or forms, and has partially cured, it is possible to remove the falsework and/or forms while the concrete fully cures. This enables the props, falsework and/or forms to be used again while the concrete fully cures.

It may be difficult to remove falsework supported by a prop as described above, since the load imparted downwardly by the inner tube, through the pin and on to the collar can make it difficult to rotate the collar. This may make it a difficult and time-consuming task to dismantle falsework supported on props as described above or may necessitate the use of special "heads" provided at the top of each prop which can be actuated to relieve the load applied to the prop before the falsework and/or forms are dismantled.

The present invention seeks to provide a prop in which the disadvantages of the prior art are obviated or reduced.

According to this invention there is provided a telescopic prop, the prop comprising an inner element provided with means defining at least one passageway therethrough, an outer tubular element adapted to receive telescopically the inner element, the outer element being provided with a pair of opposed apertures of elongate form to be co-aligned with the means defining the passageway through the first element, the second tubular element having a threaded exterior and carrying a rotatable collar engaged with the threading, there being a pin to be inserted through the mean defining the passageway in the first element and the said apertures in the second element, the pin being adapted to rest on the top of the collar engaging the collar at the opposed positions, the portion of the pin adapted to rest on the collar being of cylindrical form and being rotatable about its axis, the pin being provided with recesses substantially aligned with the parts of the collar on which the pin rests, the pin being rotatable to move the pin from a first position in which the collar engages the exterior of the pin to an alternate position in which the collar engages the recesses formed in the pin.

Preferably the first element comprises a tubular element having a plurality of passageways defined therethrough, the means defining the passageways comprising pairs of diametrically opposed apertures.

Conveniently the pin comprises a further portion extending parallel with the first linear portion, the further portion being provided with a projecting central part lying in a plane perpendicular to the plane containing the first portion and the further portion, the central part defining a recess having a diameter equivalent to the diameter of the exterior of the collar, or equivalent to the diameter of the exterior of the inner element or the outer element.

The invention also relates to a method of striking a prop as described above, the method comprising the steps of rotating the pin from a first condition in which part of the exterior of the pin engages the top of the collar to a position in which the bases of the recesses formed in the pin engage the top of the collar thus, lowering the said first telescopic member.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which FIGURE 1 is a perspective view illustrating the various components of a prop in accordance with the invention, FIGURE 2 is a view of the pin of Figure 1 from a different perspective, FIGURE 3 illustrates the prop in an operative condition, and FIGURE 4 illustrates part of the prop, with part of the pin being shown in section, after the prop has been "struck".

A prop in accordance with the invention has components which correspond with the components of the prior art prop. However, the pin of the prop is of a special form. The pin defines an axis of rotation. The pin can rotate about this axis when the pin is retained in a through-passage defined in the inner element. The parts of the pin which are intended to engage the collar are provided with regions which are at a predetermined distance from the axis of rotation of the pin which engage the collar when the pin is in one orientation, and have regions which are at a lesser distance from the axis of rotation which engage the collar when the pin is in a different orientation.Thus, by rotating the pin it is possible to move the pin from a condition in which the part of the pin at a greater distance from the axis of rotation engages the collar to a position in which the part of the pin at a lesser distance from the axis of rotation engages the collar, thus effectively lowering the pin by a predetermined distance. This lowers the inner element of the telescopic connection, thus relieving the force applied to the prop.

Referring to Figure 1 a prop in accordance with the invention comprises an inner element in the form of a tube 1 which is provided with a plurality of pairs of diametrically opposed apertures 2 at positions spaced axially along the length of the tube. Each pair of apertures effectively defines a through-passage extending across the tube.

The inner tube 1 is adapted to be telescopically received within an outer tube 3. The outer tube 3 is provided with a pair of diametrically opposed aligned apertures 4. The apertures 4 are of elongate or oval form and extend axially of the tube. The exterior of the lower tube 3 is provided with threading 5, at least in the region of the apertures 4.

A collar 6 is provided adapted to be threadingly engaged with the threading 5 provided on the tube 3. The collar 6 is of tubular form, and the interior of the collar is provided with threading 7. Means are provided to rotate the collar 6, in the form of a projecting lug 8 to which is connected a tommy bar 9. In alternative embodiments of the invention alternative means may be provided for rotating the collar 6. The collar 6 may be provided with at least part of its exterior defining two opposed flat surfaces adapted to be engaged by a spanner or the like, or the collar 6 may be provided with integrally formed lugs adapted to be struck by a hammer or the like.

In this embodiment the collar 6 is provided, at its upper end, with an outwardly directed flange 10 which defines an annular upper support surface 11.

A pin 12 is provided adapted to co-operate with the other components of the prop. The pin 12 comprises an initial substantially linear portion 13 of circular section. Two recesses 14,15 are formed in the exterior surface of the linear portion 13 of the pin, the recesses being spaced apart by a distance equal to the diameter of the flange 10. Each recess 14,15 has a flat base 16,17, the base lying in a plane which is parallel with the axis of the linear part 13 of the pin 12. The base 16,17 of each recess 14,15 lies closer to the axis of the cylindrical linear part 13 of the pin 12 than the outer periphery of the cylindrical part 13 of the pin 12.

The cylindrical linear part 13 of the pin 12 is dimensioned to be received slidingly through the opposed apertures 4 and a selected pair of the opposed apertures 2, with the linear part 13 being a snug fit within the opposed apertures 2, but being capable of rotating about its own axis. Consequently the diameter of the linear cylindrical portion 13 of the pin 12 is slightly less than the diameter of each of the opposed pairs of apertures 2.

The linear portion 13 of the pin 12 terminates, at one end, with a substantially 180 "U" bend 18 which extends to a further portion 19 of the pin which extends substantially parallel with the linear portion 13. The central region of the further portion 19 is deflected to form a deflection 20. If the linear portion 13 and the substantially parallel further portion 19 lie in a predetermined plane, the projection 20 lies in a plane which is perpendicular to the predetermined plane. The projection 20 defines a recess 21, the diameter of the recess 21 being slightly greater than the outer diameter of the collar 6.

It is to be noted that the bases 16,17 of the recesses 14,15 are substantially parallel with the said "predetermined plane" and the recesses 14,15 are open on the side of that "predetermined plane" which is opposite the side on which the projection 20 extends away from that "predetermined plane".

When assembling the prop of the present invention the collar 6 is threadingly engaged with the threading 5 on the exterior of the tube 3 and the collar is located at a position where the upper flange 11 is located towards the bottom of the elongate apertures 4. The tube 1 is then telescopically inserted into the outer tube 3, and the tube 1 is moved to a position in which the top of the tube 1, or a head carried thereby, engages the item that is to be supported by the prop. The linear cylindrical portion 13 of the pin 12 is then inserted through a selected pair of the apertures 2 which are aligned with the aperture 4, the pair of apertures closest to the collar 11 usually being selected. The collar 6 may then be rotated to be moved upwardly, and the pin 12 will be moved to a position such that the collar 6 is received within the recess 21.This serves to locate the pin 12 in a desired position with the recesses 14,15 aligned with diametrically opposed points on the flange 10.

The "predetermined plane" which contains the linear cylindrical portion 13 and the parallel linear portion 19 is substantially vertical. This means that the bottom portions 16,17 of the recesses 14,15 are also substantially vertical.

The collar is then moved upwardly, and the upper surface 11 defined by the flange 10 will engage part of the exterior of the linear cylindrical portion 13 of the pin 12. This part of the exterior of the pin 12 will be located a distance from the axis of rotation of the pin which is equal to the radius of the cylindrical portion 13 of the pin. This is because the linear portion of the pin 13 is a snug fit within the opposed apertures 2 in which it is received, and thus the axis of rotation is the axis of the linear cylindrical portion.

The collar 6 is moved upwardly until the pin 12 and thus the inner tube 1 have been moved upwardly so that the prop firmly supports that which is to be supported by the prop.

When the prop is to be removed or "struck" a hammer or other implement may be used to strike part of the linear portion 19 of the pin 12, or a bar or rod may be inserted between the two linear portions 13,19 of the pin to apply a rotatonal force to the pin, to cause the pin to rotate about the axis of rotation defined by the cylindrical portion 13 of the pin. The pin will rotate by approximately 90 As the pin rotates the bases 16,17 of the recesses 14,15 come into engagement with the annular supports surface 11 defined by the flange 10. This can be seen most clearly in Figure 4. Thus, the surface of the pin now engaging the upper surface 11 of the flange 10 is closer to the axis of rotation of the pin than was previously the case. In other words, the pin has been lowered by a distance equal to the depth of the recesses 14,15. Since the pin has been lowered by this distance the inner tube 1 has also been lowered by this distance. This means that the stress applied to the prop has been relieved, and the prop, and any associated equipment, may easily be removed.

In an alternative embodiment, if the spacing between the linear portions 13,19 of the pin is sufficiently greater, the recess 21 will engage the lower tube 3, and the recess may have a diameter equivalent to theouter diameter of the tube 3. In a further embodiment the portion 19 of the pin may lie above the linear portion 13 instead of below it. In this case the recess 21 will lie adjacent the inner tube 1, and the diameter of the recess 21 may be equivalent to the exterior diameter of the inner tube 1.

Claims

CLAIMS:

1. A telescopic prop, the prop comprising an inner element provided with means defining at least one passageway therethrough, an outer tubular element adapted to receive telescopically the inner element, the outer element being provided with a pair of opposed apertures of elongate form to be co-aligned with the means defining the passageway through the first element, the second tubular element having a threaded exterior and carrying a rotatable collar engaged with the threading, there being a pin to be inserted through the mean defining the passageway in the first element and the said apertures in the second element, the pin being adapted to rest on the top of the collar engaging the collar at the opposed positions, the portion of the pin adapted to rest on the collar being of cylindrical form and being rotatable about its axis, the pin being provided with recesses substantially aligned with the parts of the collar on which the pin rests, the pin being rotatable to move the pin from a first position in which the collar engages the exterior of the pin to an alternate position in which the collar engages the recesses formed in the pin.

2. A prop according to Claim 1 wherein the first element comprises a tubular element having a plurality of passageways defined therethrough, the means defining the passageways comprising pairs of diametrically opposed apertures.

3. A prop according to Claim 1 or Claim 2 wherein the pin comprises a further portion extending parallel with the first linear portion, the further portion being provided with a projecting central part lying in a plane perpendicular to the plane containing the first portion and the further portion, the central part defining a recess having a diameter equivalent to the diameter of the exterior of the collar, or equivalent to the diameter of the exterior of the inner element on the outer element.

4. A method of striking a prop according to Claim 1, the method comprising the steps of rotating the pin from a first condition in which part of the exterior of the pin engages the top of the collar to a position in which the bases of the recesses formed in the pin engage the top of the collar thus, lowering the said first telescopic member.

5. A prop substantially as herein described with reference to and as shown in the accompanying drawings.

6. Any novel feature or combination of features disclosed herein.