EP3835513B1

EP3835513B1 - Safety device for struts

Info

Publication number: EP3835513B1
Application number: EP19383096.5A
Authority: EP
Inventors: José Luis Ubiñana Félix
Original assignee: Sistemas Tecnicos de Encofrados SA
Current assignee: Sistemas Tecnicos de Encofrados SA
Priority date: 2019-12-11
Filing date: 2019-12-11
Publication date: 2022-08-31
Anticipated expiration: 2039-12-11
Also published as: WO2021116515A1; EP3835513A1

Description

BACKGROUND OF THE INVENTION

There are several formwork removal mechanisms or safety devices for struts known in the state of the art. For example, document FR2712017 discloses a safety device supported by a strut on an external thread. The safety device consists of a pin, which is affixed to said device on one side, and on the other, to the telescopic tube of the strut. In turn, on its side affixed to the telescopic tube, the pin is supported by a horizontal surface of the safety device, adjacent to which there is a ramp or step descending to a depression. When the safety device is displaced horizontally by means of a blow, the pin falls from the horizontal surface into the depression, while the telescopic tube of the strut also descends as required for removing the formwork. As a safety measure to prevent the safety device from becoming disassembled accidentally, the safety device comprises an internal spring that exerts a force in the direction opposite the disassembly direction.
Another example of a safety device is the one shown in document EP1975341 . This safety device differs from the one described previously in that the pin is not affixed to the safety device but rather, in order to prevent the device from becoming disassembled accidentally, it has a rotational configuration in which, while in a rest condition, it blocks the displacement of the safety device. In order to unblock the safety device, the operator must first rotate the pin.
It should be noted that the struts used in formwork can withstand tonnes of weight, due to which they need a reliable support mechanism, as well as a fast and convenient disassembly system for the operator, as the formwork can have hundreds or thousands of struts that need to be disassembled. However, as can be inferred from the mechanisms known in the state of the art, either the safety element is unreliable, or the operator needs to make significant effort either to deactivate the safety element and/or to displace the safety device to the disassembly position.
Therefore, there is still a need for a robust safety device which is cost effective to manufacture and that can be quickly and conveniently mounted and dismounted by an operator. This and other objects are achieved by a safety device according to claim 1 and thereupon dependent claims.

DESCRIPTION OF THE INVENTION

The present invention consists of a safety device for struts intended for use in struts of the type comprising:

an outer tube with an upper threaded portion in which there are two longitudinal and diametrically opposed slots,
an inner tube telescopically housed in the outer tube and comprising at least two diametrically opposed holes,
an internally threaded nut or bushing, which can be threaded to the upper threaded portion of the outer tube, and
a pin that can be housed both in the two slots of the outer tube and in the two holes of the inner tube.

The present safety device for struts comprises a base with at least one U-shaped portion, and may have other added portions, which for example close the open end. This base is intended, in a lock condition of the safety device, to be positioned with that portion of its extremities around the upper threaded portion of the outer tube, while being supported by the nut and by the central section of the base separated from the outer tube. Therefore, the separation between the extremities, at least in one section thereof, must be longer than the width of the outer tube to ensure it can be positioned around the upper threaded portion of the outer tube. At the same time, this separation between the extremities must be shorter than the length of the pin, in order to support the pin, as well as shorter than the width of the nut, in order to be supported by said nut.
The novelty of the safety device for struts is defined by two peculiarities. The first is that the upper surface of each extremity of the base comprises an inclined portion, both inclined portions being symmetrical to each other relative to the vertical plane of symmetry of the base and the lower ends thereof being situated on the side of the central section of the base. The second consists of a latch, which has at least one U-shaped portion and which is affixed in an articulated manner by its central section to the central section of the base, which may freely rotate relative to an axis perpendicular to the vertical plane of symmetry of the base. The size of this latch is such that, in a lock condition of the safety device, the extremities thereof rest on said inclined portions to thus hold the pin supported by said inclined portions. In turn, at least one of the extremities thereof comprises a protrusion to facilitate the rotation of the latch from its locking position to an unlocking or opening position.
Thanks to this configuration of a safety device for struts, an operator can dismount the strut with only two slight taps. The first tap is to rotate the latch from its locking position to an unlocking position, and the next tap is to move the safety device horizontally and lower the pin. Thanks to the inclination of the inclined portions, the safety device moves and the pin is released without the need for a strong impact (or the sequence of several impacts), with the convenience that this means for the operator.
Optionally, the base of the safety device may include steps linking the lower ends of the inclined portions to lower sections, which may preferably be horizontal. This way, moving the safety device slightly is enough for releasing the pin.
The base can comprise a protrusion to enable horizontal displacement by means of a blow of a hammer in the central section of the base.
Preferably, the central section of the latch is affixed at a height equal to or lower than the position of the extremities resting on the inclined portions. This way, the latch receives virtually no weight from the strut, and the rotation thereof from the locking position to an unlocking position requires little effort from the operator.
In order to place the safety device for struts on a strut that has already been mounted, the ends of the base can be previously separated from each other. In this case, once placed on the strut, the extremities of the base can receive a connecting piece, which closes the contour of the safety device and prevents it from coming out of the strut. In another possible embodiment, the ends of the base are joined from the beginning, and the base can be made of one have a one-piece construction which must be inserted into the strut during the assembly thereof.
Preferably, to prevent the inclined portions from deteriorating due to the pressure exerted by the pin, they may comprise an upper surface that is heat-treated to be hardened.
The present safety device for struts provides a mechanism that makes it possible to remove struts quickly and safely through operations that require little effort from the operator. In turn, the savings in manpower provided by the use of the safety device for struts translates into a reduction in the cost of executing the works, such that the investment that is required for using this safety device for struts is recovered very quickly.
These and other features and advantages of the safety device for struts object of the present invention will be evident from the description of a preferred, but not exclusive, embodiment, which is illustrated by way of a nonlimiting example in the drawings provided herein:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1.- A perspective view of a strut in an embodiment of the present safety device for struts.
Figure 2.- An extension of the detail II indicated in Figure 1.
Figure 3A.- A plan view of a first embodiment of the present safety device for struts.
Figure 3B.- A plan view of a second embodiment of the present safety device for struts.
Figure 3C.- A side view of the second embodiment of the present safety device for struts.
Figure 4.- A side view of the first embodiment of the safety device in the lock condition of the strut.
Figure 5.- A side view of the first embodiment of the safety device in the recovery condition of the strut.
Figure 6.- A perspective view of the first embodiment of the safety device in the lock condition of the strut.
Figure 7.- A perspective view of the first embodiment of the safety device with the latch in an unlocking position, prior to the recovery condition of the strut.
Figure 8.- A perspective view of the first embodiment of the safety device prior to the insertion of the base thereof into the strut.
Figure 9.- A perspective view of the first embodiment of the safety device prior to the placement of the connecting piece in the base of the safety device.
Figure 10.- A perspective view of the first embodiment of the safety device prior to the placement of the latch in the locking position thereof.
Figure 11.- A perspective view of the first embodiment of the safety device in the lock condition of the strut.

DESCRIPTION OF A PREFERRED EMBODIMENT

As shown in Figures 1 and 2, the present invention consists of a safety device (1, 1') for struts intended to be used with struts of the type comprising an outer tube (TE) with an upper threaded portion comprising two longitudinal and diametrically opposed slots, an inner tube (TI) telescopically housed in the outer tube (TE) comprising at least two diametrically opposed holes, a nut (N) that can be threaded to the upper threaded portion of the outer tube (TE), and a pin (P) that can be housed both in the two slots of the outer tube (TE) and in the two holes of the inner tube (TI).
As shown in Figures 3A and 3B more clearly, the preferred embodiments of the safety device (1, 1') for struts comprise a base (2, 2') with a U-shaped portion, with the separation between the extremities (22, 22') thereof being longer than the width of the outer tube (TE) and shorter than the length of the pin (P), as well as the width of the nut (N), in order to be supported by said nut (N).
In the embodiment of the safety device (1) shown in Figure 3A, the extremities (22) of the base (2) comprise a connecting piece (25), which closes the contour of the safety device (1) once placed on the strut, to prevent it from coming out of the strut. This embodiment is suitable for struts whose tubes (TE, TI) have already been assembled. On the other hand, in the embodiment of the safety device (1') shown in Figure 3B, the extremities (22') of the base (2') are joined by an extension thereof, due to which the base can be made of one piece. This embodiment is more cost effective to manufacture, although it must be placed on the strut before the tubes (TE, TI) thereof are assembled.
In any of the embodiments, as shown in Figure 3C, the upper surface of each extremity (22, 22') of the base (2) comprises an inclined portion (23), both inclined portions (23) being symmetrical to each other relative to the vertical plane of symmetry of the base (2) and the lower ends thereof being situated on the side of the central section (21) of the base (2). In turn, the safety device (1, 1') for struts comprises a latch (3), which has a U-shaped portion affixed in an articulated manner by its central section (31) to the central section (21) of the base (2, 2') and may freely rotate relative to an axis (A) perpendicular to the vertical plane of symmetry of the base (2, 2') shown in Figures 2, 3A and 3B.
As shown in Figure 3C, the size of the latch (3) is such that the extremities (32) of the latch (3) can rest on said inclined portions (23) when the central section (21) of the base (2, 2') is separated from the outer tube (TE). Thus, in its lock condition, the latch holds the pin (P) over the inclined portions (23), as shown in Figure 4.
In the embodiments shown in the figures, the base (2, 2') of the safety device (1) comprises steps that link the lower ends of the inclined portions (23) to lower sections (24), which are horizontal in these embodiments. In a lock condition of the safety device (1, 1') for struts shown in Figure 4, the pin (P) is held in the inclined portions (23) thanks to the operation of the latch (3), the extremities (23) of which also rest on the inclined portions (23). In a recovery condition of the strut shown in Figure 5, the safety device (1, 1') for struts has been displaced horizontally, lowering the pin (P) to the lower sections (24) accompanied by the inner tube (TI). This way, the strut is released from the formwork it supported and can be easily recovered.
To facilitate the rotation of the latch (3) from its locking position to an unlocking or opening position, in these embodiments each extremity (32) of the latch (3) comprises a protrusion (33) which can be hit upwards, as can be inferred by the position of the square face of the hammer shown in Figure 6.
Also, to enable the blow of the hammer in the central section (21) of the base (2, 2') once the latch (3) is in an unlocking position, this embodiment comprises a protrusion (20) which can be hit horizontally, as can be inferred by the position of the square face of the hammer shown in Figure 7.
In this preferred embodiment, the central section (31) of the latch (3) is affixed at a height that is slightly lower than the position of the extremities (32) resting on the inclined portions (23). This way, the latch (3) receives virtually no weight from the strut, due to which its rotation from the locking position to an unlocking position requires little effort from the operator.
In order to place the safety device (1, 1') for struts on a strut that has already been mounted, the ends of the base (2) can be previously separated from each other, as shown in Figure 8. Once placed on the strut, the extremities (23) of the base (2) can receive the connecting part (25), shown in Figure 9, which closes the contour of the safety device (1) and prevents it from coming out of the strut. After placing the safety device (1), the operator can now insert the pin (P) through the corresponding slots and holes, as shown in Figure 10, to finally place the latch (3) in its locking position, as shown in Figure 11.
As shown in Figures 4 to 11, the nut (N) can comprise a drive lever configured to thread the nut to the threaded portion of the outer tube (TE) when actuated by a user.

Claims

A safety device (1, 1') for struts adapted to be used with struts of the type comprising an outer tube (TE) with an upper threaded portion comprising two longitudinal and diametrically opposed slots, an inner tube (TI) telescopically housed in the outer tube (TE) comprising at least two diametrically opposed holes, a nut (N) that can be threaded to the upper threaded portion of the outer tube (TE), and a pin (P) that can be housed both in the two slots of the outer tube (TE) and in the two holes of the inner tube (TI), the safety device (1, 1') for struts comprising a base (2, 2'), which:
- has at least one U-shaped portion, defined by a central section (21), and extremities (23), with the separation between at least one portion of the extremities (22, 22') thereof being longer than the width of the outer tube (TE), while being shorter than the length of the pin (P) and the width of the nut (N), and

- is adapted in a lock condition of the safety device (1, 1') for struts, to be positioned with said portion of the extremities (22, 22') thereof around the upper threaded portion of the outer tube (TE), while being supported by the nut (N) and with the central section (21) of the base (2, 2') being separated from the outer tube (TE), the safety device (1, 1') for struts having

- the upper surface of each extremity (22, 22') of the base (2, 2') comprising an inclined portion (23), both inclined portions (23) of said extremities (22,22') being symmetrical to each other relative to the vertical plane of symmetry of the base (2, 2') and the lower ends thereof being situated on the side of the central section (21) of the base (2, 2'), and being characterised in that the safety device comprises a latch (3) with at least one U-shaped portion affixed in an articulated manner by its central section (31) to the central section (21) of the base (2, 2'), which can freely rotate relative to an axis (A) perpendicular to the vertical plane of symmetry of the base (2, 2'), having at least one protrusion (33) comprised in at least one of the extremities (32), the size thereof being such that, in its lock condition, the extremities (32) thereof can rest on said inclined portions (23).
The safety device (1, 1') for struts according to claim 1, characterised in that the central section (31) of the latch (3) is affixed at the base (2, 2') at a height equal to or lower than the position of the extremities (32) thereof when resting on the inclined portions (23).
The safety device (1, 1') for struts according to any of the preceding claims, characterised in that it comprises steps that link the lower ends of the inclined portions (23) to lower sections (24) of the upper surface of the base (2, 2').
The safety device (1, 1') for struts according to any of the preceding claims, characterised in that it comprises a protrusion (20) in the central section (21) of the base (2, 2'), which is enabled to receive an impact.
The safety device (1, 1') for struts according to any of the preceding claims, characterised in that the inclined portions (23) comprise an upper surface that has been heat-treated to be hardened.
The safety device (1, 1') for struts according to any of the preceding claims, characterised in that the extremities (22, 22') of the base (2, 2') are joined by the ends thereof.
The safety device (1, 1') for struts according to claim 6, characterised in that it comprises a connecting piece (25) affixed to both extremities (22) of the base (2).
The safety device (1, 1') for struts according to claim 6, characterised in that the base (2') is made from one piece.