EP2422028B1

EP2422028B1 - Construction prop

Info

Publication number: EP2422028B1
Application number: EP10718306.3A
Authority: EP
Inventors: Franciscus Jozef Leonardus Hubertus Brinkmann
Original assignee: Scafom International BV
Current assignee: Scafom International BV
Priority date: 2009-04-24
Filing date: 2010-04-23
Publication date: 2016-07-13
Anticipated expiration: 2030-04-23
Also published as: CN102439249B; PL2422028T3; CN102439249A; EP2422028A1; NL2002800C2; WO2010123360A1

Description

Field of the invention

The invention relates to a construction prop.

State of the art

Constructions props have been known for many years. Examples of construction props are described in GB-755831 and DE694113U . These known construction props comprise an outer pipe with a longitudinal central axis. The known outer pipe is provided with a foot at a lower end of the outer pipe and screw thread adjacent an upper end of the outer pipe. Further, two slotted holes are provided the screw thread which extend in a direction parallel to the longitudinal central axis and which are provided diametrically relative to each other in the outer pipe. The known construction props further comprise an inner pipe which is slideably received in the outer pipe. The inner pipe is provided with a series of pairs of holes which are arranged over a part of the length of the inner pipe, while the two holes of each pair of holes are disposed diametrically relative to each other in the inner pipe. The known construction prop further comprises an adjusting nut which is provided with internal screw thread which is configured for cooperation with the screw thread of the outer pipe. The construction prop further comprises a supporting pin which, in use, extends through one of the pairs of holes of the inner pipe and the slotted holes in the outer pipe and which bears on a top of the adjusting nut. The inner pipe can be height-adjusted by inserting the supporting pin into another pair of holes of the inner pipe. Fine-tuning the height can be obtained through rotation of the adjusting nut. In order to prevent the inner pipe from falling from the outer pipe, the inner pipe can be provided adjacent a lower end thereof with a widening and the outer pipe can be provided adjacent an upper end thereof-with a reduced portion. The widening and the reduced portion should be geared to each other such that the widening cannot pass the reduced portion. With the construction prop of GB-755831 , the reduced portion is above the portion provided with screw thread. With the construction prop of DE694113U , the reduced portion is directly below the threaded portion. In DE694113U , also, the inside diameter of the threaded portion is also smaller than the inside diameter of the remaining part of the outer pipe, so that a better guiding of the inner pipe relative to the outer pipe is obtained and furthermore, the risk of skewness of the inner pipe relative to the outer pipe is minimized.
When construction props are removed, for instance when a story floor supported by the prop no longer requires this support by the prop, it is customary that a worker hits the outer pipe adjacent a lower end thereof with a large hammer, a beam or such auxiliary means. Then, the lower end of the construction prop tilts away and the construction prop can be removed. This course of action allows for a rapid removal of a number of props. However, a drawback of this course of action is that dents may be formed in the outer pipe adjacent the lower end. These dents may cause that the widening of the inner pipe can no longer pass the dent, so that the inner pipe can no longer be completely slid into the outer pipe. This is unfavourable in the transport of the construction props and furthermore reduces the ease of manipulation of the construction prop.
It is known from practice to reinforce the lower end of the outer pipe by providing a protective steel sleeve over the lower end of the outer pipe. However, such a steel protective sleeve leads to increase of weight of the construction prop as a whole. A sleeve with a length of 15 - 30 cm and a wall thickness of 3 mm and an inside diameter of approximately 63.5 mm can easily weigh 1 - 2 kg.
Such a solution is also disclosed in EP-0 493 184 A1 . This publication also discloses a reinforcement in the inside of outer pipe in the form of steel sleeve and, alternatively, in the form of annular rings that are welded on the inside of the outer pipe.
DE 19844613 discloses a scaffolding pole having reinforcement sleeves that are crimped on the outer surface of the scaffolding pole adjacent a connection arrangement for ledgers.
The problem of damage and the possibility of the formation of dents has already been recognized in the state of the art of construction props. To that end, reference is made to WO92/13156 in which is disclosed the provision of axial profiling in the outer pipe for providing that dents in the outer pipe do not hinder the telescopic movement of the inner pipe relative to the outer pipe. The same idea is described in the later patent application WO2008/049780 . A drawback of axial profiling, and in particular in the manner in which it is applied in WO2008/049780 , i.e. with a wave form profile with the pitch distance between the crests of two neighbouring waves being relatively small relative to the pipe circumference, is that upon loading the outer pipe transversely to the pipe surface, i.e. in a direction transversely to the longitudinal central axis of the outer pipe, the outer pipe can be readily squashed. The axial profiling provides a deformation possibility known from an accordion or a bellows. An outer pipe which is somewhat squashed at the axial profiling under the influence of a load and the more limited resistance to deformation as a result of the axial profiling, is much more susceptible to bend when the outer pipe is loaded in the direction of the longitudinal central axis again.
The object of the invention is to provide a construction prop with which the above-mentioned drawbacks are at least partly remedied.

Summary of the invention

Therefore, the object of the invention is a construction prop which is provided with a foot reinforcement that does not lead to weight increase nor is susceptible to squashing of the pipe under the influence of a force applied to the pipe wall perpendicularly to the longitudinal central axis.
To that end, a construction prop is provided with:

an outer pipe with a longitudinal central axis, the outer pipe being provided with:
- ∘ a foot at a lower end of the outer pipe;
- ∘ screw thread adjacent an upper end of the outer pipe;
- ∘ two slotted holes which are located at the screw
  thread and which extend in a direction parallel to the longitudinal central axis and which are provided diametrically relative to each other in the outer pipe;
an inner pipe which is slideably received in the outer pipe and which is provided with:
- ∘ a series of pairs of holes arranged over a part of the length of the inner pipe, wherein the two holes of each pair of holes are disposed diametrically relative to each other in the inner pipe;

The construction prop is characterized according to the invention in that the outer pipe comprises a foot reinforcement adjacent a lower end of the outer pipe, having a number of creases which each extend in tangential direction around the entire circumference of the outer pipe, wherein each crease extends in an imaginary plane which extends perpendicularly to the longitudinal central axis, wherein the tangential creases are provided in an area of the outer pipe which extends from adjacent the lower end of the outer pipe over a length of 10 - 50 cm, and wherein the tangential creases are provided through plastic deformation of the pipe wall and have a wave-shaped cross-sectional profile viewed in a cross-sectional plane in which also the longitudinal central axis extends.
Such a profiling with tangential creases does not weaken the outer pipe in case of squashing upon loading in a direction perpendicular to the longitudinal central axis. On the contrary, the risk of squashing is even reduced by the tangential creases. Furthermore, when dents are formed when the lower end of the construction prop is hit with a large hammer, a beam or such auxiliary means, these dents will be formed on the outwardly facing crests of the tangential creases. Creases provided there do not hinder the possibility of telescopic movement of the inner pipe relative to the outer pipe, so that also with such dents present, the inner tube can be slid completely into the outer pipe. These advantages are achieved without any increase in weight of the construction prop when compared to a construction prop that is not provided with a foot reinforcement.
Further elaborations of the invention are described in the subclaims and will be further elucidated in the following on the basis of a few exemplary embodiments with reference to the drawing.

Brief description of the drawing

Fig. 1 shows a perspective view of an exemplary embodiment of a construction prop;
Fig. 1A shows a detail A of Fig. 1;
Fig. 2 shows a first exemplary embodiment of a foot reinforcement;
Fig. 3 shows a cross-sectional view of the exemplary embodiment shown in Fig. 2;
Fig. 4 shows a second exemplary embodiment of a foot reinforcement; and
Fig. 5 shows a cross-sectional view of the exemplary embodiment represented in Fig. 4.

Detailed description

In one embodiment, of which an example is shown in Fig. 1 and of which a detail is shown in Fig. 1A, a construction prop 10 comprises an outer pipe 12 with a longitudinal central axis L. The outer pipe 12 is provided with a foot 14 at a lower end of the outer pipe 12. Adjacent an upper end of the outer pipe 12, screw thread 16 is provided. At the screw thread, there are two slotted holes 18 which extend in a direction parallel to the longitudinal central axis L and which are provided diametrically relative to each other in the outer pipe 12. The construction prop 10 further comprises an inner pipe 20 which is slideably received in the outer pipe 12. The inner pipe 20 is provided with a series of pair of holes 22 which are arranged over a part of the length of the inner pipe 20. The two holes of each pair of holes 22 are disposed diametrically relative to each other in the inner pipe 20. In an embodiment of which an example is shown in Fig. 1, an upper end of the inner pipe 20 can be provided with an end plate 24 which has a substantially flat top surface extending substantially perpendicularly to the longitudinal central axis. The construction prop is generally provided with an adjusting nut 26 which is provided with inside screw thread configured for cooperation with the screw thread 16 of the outer pipe 12. The construction prop further generally comprises a supporting pin 28 which, in use, extends through one of the pairs of holes 22 of the inner pipe 20 and the slotted holes 18 in the outer pipe 12 and which bears on a top of the adjusting nut 26. In one embodiment, of which an example is shown in Figs. 1 and 1A, the inner pipe 20 can be provided with a height marking 30. Such a height marking 30 simplifies the choice of the correct pair of holes 22 for inserting the support pin 28. After the rough-tuning of the inner pipe 20 relative to the outer pipe 12 through the choice of the correct pair of holes 22 for inserting the support pin 28, with the adjusting nut 26, fine-tuning can be provided of at the construction prop 10.
In one embodiment, of which an exemplary embodiment is shown in Fig. 1, at the centre of gravity of the construction prop 10, when the inner pipe 20 is in the most slid-in condition in the outer pipe 12, the outer pipe 12 can be provided with a centre of gravity marking 32. In the exemplary embodiment of Fig. 1, the centre of gravity marking 32 is designed as a line marking extending in tangential direction around the outer pipe 12. It is clear that also other designs of the centre of gravity marking 32 are possible. A centre of gravity marking 32 simplifies picking up the construction prop 10 by a user. The fact is that when the user picks up the construction prop 10 at the centre of gravity marking, the construction prop 10 will be directly in equilibrium, without the user having to correct his point/location of engagement.
The height marking 30 and the centre of gravity marking 32 can be provided with the aid of, for instance, a punching operation or an etching operation. A thus provided marking 30, 32 can be made more striking by giving the marking a colour that deviates from the colour of the rest of the construction prop 10. It is also possible to provide a height marking 30 and/or centre of gravity marking 32 only by applying colours, therefore without a punching or etching operation. The construction prop 10 is further provided with a foot reinforcement 34 adjacent a lower end of the outer pipe 12.
Figs. 2 - 5 show two exemplary embodiments of a foot reinforcement in more detail. According to the invention, the foot reinforcement 34 comprises a plurality of creases 36 which each extend in tangential direction around the entire circumference of the outer pipe 12. Each crease 36 extends in an imaginary plane P1, P2, ... Pn which extends perpendicularly to the longitudinal central axis L. The tangential creases 36 do not weaken the outer pipe 12 in case of squashing due to a force applied to the pipe wall in a direction perpendicularly to the longitudinal central axis L. On the contrary, the tangential creases 36 reinforce the outer pipe 12 against such a load. Furthermore, the tangential creases 36 offer protection against formation of dents which may occur as a result of a large hammer or beam being hit against the lower side of the outer pipe 12; which operation may be carried out when construction props are removed. Dents may still be formed, however, these dents are formed in the parts of the tangential creases 36 located radially outwardly. The parts of the tangential creases 36 located radially inwardly remain undamaged. Therefore, sliding the inner pipe 20 inwardly or outwardly relative to the outer pipe 12 can take place unhindered, even when there is some extent of denting. The tangential creases 36 are provided in an area of the outer pipe 12 which extends from adjacent the lower end of the outer pipe 12 over a length of 10 - 50 cm. In the example shown, the length of the area over which tangential creases have been provided from the foot 14 is approximately 15 cm. The tangential creases 36 are provided through plastic deformation of the pipe wall. The tangential creases 36 have a wave-shaped cross sectional profile viewed in a cross sectional plane in which also the longitudinal central axis L extends, as shown in Figs. 3 and 5. In the exemplary embodiments shown, the crests 36a, 36c turned radially outwardly and the bases 36b, 36d of the wave-shaped cross sectional profile are not equally long. In the exemplary embodiment of Figs. 2 and 3, the crests 36a turned radially outwardly are short relative to the bases 36b which extend in the same cylindrical plane as the rest of the wall of the outer pipe 12. In the exemplary embodiment of Figs. 4 and 5 for that matter, the crests 36c turned radially outwardly are long relative to the bases 36d which extend in the same cylindrical plane as the rest of the wall of the outer pipe 12. In a further alternative embodiment, the length of the crests and the bases of the wave-shaped profile of the tangential creases 36 can indeed be equally long.
In one embodiment, of which an example is shown in the drawing, the distance D between the crests 36a or 36c of two neighbouring creases 36 can be in the range of 0.5 to 3.5 cm. With such a distance, it is sufficiently provided that impact with a large hammer or beam does not lead to dent formation in the parts of the foot reinforcement 34 located radially inwardly. In the exemplary embodiment shown, the distance D is approximately 25 mm.
Although the invention is represented and described in detail with reference to the drawing, this drawing and description should be considered to be only an example. The invention is limited to the scope of the claims provided. In one embodiment for instance, the foot reinforcement 34 can also comprise axial creases in addition to the tangential creases 36. The axial creases, which are provided through plastic deformation of the outer pipe wall, can promote guiding of the inner pipe relative to the outer pipe while still the resistance against squashing of the outer pipe is retained as a result of the presence of the tangential creases. Reference numerals in the claims should not be understood to be limitations of the claims but serve as clarification only.

Claims

A construction prop comprising:
• an outer pipe (12) with a longitudinal central axis (L), the outer pipe (12) being provided with:
∘ a foot (14) at a lower end of the outer pipe (12);

∘ screw thread (16) adjacent an upper end of the outer pipe (12);

∘ two slotted holes (18) which are located at the screw thread (16) and which extend in a direction parallel to the longitudinal central axis (L) and which are provided diametrically relative to each other in the outer pipe (12);

• an inner pipe (20) which is slideably received in the outer pipe (12) and which is provided with:
∘ a series of pairs of holes (22) arranged over a part of the length of the inner pipe (20), wherein the two holes of each pair of holes (22) are disposed diametrically relative to each other in the inner pipe (20);
characterized in that the outer pipe (12) comprises a foot reinforcement (34) adjacent a lower end of the outer pipe (12), having a plurality of creases (36) which each extend in tangential direction around the entire circumference of the outer pipe (12), wherein each crease (36) extends in an imaginary plane (P1, P2, ... Pn) which extends perpendicularly to the longitudinal central axis (L), wherein the tangential creases (36) are provided in an area of the outer pipe (12) which extends from adjacent the lower end of the outer pipe (12) over a length of 10 - 50 cm, and wherein the tangential creases (36) are provided through plastic deformation of the pipe wall and have a wave-shaped cross-sectional profile viewed in a cross-sectional plane in which also the longitudinal central axis (L) extends.
A construction prop according to claim 1, wherein the distance (D) between the crests (36a, 36c) of two neighbouring creases is in the range of 0.5 to 3.5 cm.
A construction prop according to any one of the preceding claims, further comprising:
• an adjusting nut (26) which is provided with internal screw thread configured for cooperation with the screw thread (16) of the outer pipe (12).
A construction prop according to claim 3, further comprising:
• a supporting pin (28) which, in use, extends through one of the pairs of holes (22) of the inner pipe (20) and the slotted holes (18) in the outer pipe (12) and which bears on a top of the adjusting nut (26).
A construction prop according to any one of the preceding claims, comprising:
• an end plate (24) which is connected to an upper end of the inner pipe (20) and which is provided with a substantially flat top surface extending substantially perpendicularly to the longitudinal central axis (L).
A construction prop according to any one of the preceding claims, comprising:
• a height marking (30) which is provided on the inner pipe (20).
A construction prop according to any one of the preceding claims, comprising:
• a centre of gravity marking (32) on the outer pipe (12) at the centre of gravity of the construction prop (10) when the inner pipe (20) is in a most slid-in condition in the outer pipe (12).
A construction prop according to any one of the preceding claims, comprising:
• axial creases in the foot reinforcement (34) which cross the tangential creases (36).