EP2071100A1

EP2071100A1 - Wind lock

Info

Publication number: EP2071100A1
Application number: EP07122793A
Authority: EP
Inventors: Joakim Svedberg
Original assignee: Combisafe International AB
Current assignee: Combisafe International AB
Priority date: 2007-12-10
Filing date: 2007-12-10
Publication date: 2009-06-17
Also published as: WO2009074302A1

Abstract

This invention relates to a wind lock device (200) for stabilizing a construction safety screen which comprises a net support (140) with a fundament (101) and a lever arm (102), which lever arm is pivotally connected to the fundament at a first end portion of the lever arm. The safety screen is operable between a folded state and an unfolded state with the lever arm unfolded a predetermined angle from the fundament. The wind lock device comprises a first bracket member (201) which is pivotally arranged at the lever arm. The wind lock device is further arranged to engage with the fundament of the net support in the unfolded state of the construction safety screen. The wind lock device comprises an operating member (205) arranged to allow lifting the first bracket member when folding the net support.

Description

FIELD OF THE INVENTION

The present invention relates to construction safety screens, and more particularly to a wind lock device for stabilizing a construction safety screen and a construction safety screen with such a wind lock device.

BACKGROUND OF THE INVENTION

Safety systems designed for use on building structures during construction work and renovation are in first hand used to protect the construction workers and other people who occupy themselves in the near surroundings of the construction site. These safety systems typically comprise construction safety screens that are used to prevent workers and tools from falling from edges of the building construction.
In Fig. 1 a side view of a typical prior art construction safety screen of which is commonly used during construction work is schematically illustrated. The construction safety screen 100 comprises a net 103, and at least one net support 140 having a lever arm 102 and a fundament 101. The lever arm 102 has a first end portion 102a and a second opposite end portion 102b. The first end portion of the lever arm 102a is pivotally arranged at the fundament 101. The net 103 is typically shaped in the form of a rectangle and is along a first side of the net horizontally attached to the fundaments 101 of typically two distanced net supports 140. The horizontal attachment of the net 103 is arranged at a distance d above the pivotal connection of the first end portion of the lever arm 102a and the fundament 101. The opposite second side of the rectangle shaped net 103 is attached to the second end portion 102b of the at least one lever arm 102. The net 103 can be enforced with rods along the first and opposite second sides (not shown in the figures).
The construction safety screen 100 is operable between two states: an unfolded state as illustrated in Fig. 1a) and a folded state as illustrated in Fig. 1b). In the unfolded state the net 103 is unfolded as the lever arm 102 is tilted away from the fundament 101 forming an angle α between the fundament 101 and the lever arm 102. The angle α depends on the size of the net 103, i.e. the distance between the first and second opposite side of the net 103, the length of the lever arm 102 and the distance d. In the folded state the lever arm 102 is fully tilted towards the fundament 101 and the net 103 is relaxed.
In the unfolded state the net 103 is fully unfolded and the construction safety screen 100 as used on the construction site is likely to be exposed to substantial wind forces, especially when the construction safety screen 100 is utilized on a tall building construction.
In Fig. 1 c) a prior art construction safety screen 100 is further provided with a wind lock according to a commonly used technique on construction sites today. A rope 110 is in a first end attached to the second end portion of the lever arm 102b (or alternatively to the rods used to enforce the net) and is, when the construction safety screen is arranged in the unfolded state, further anchored in a second end in an anchoring point 111, which is arranged e.g. on a surrounding structure. The rope is stretched to stabilize the construction safety screen 100 and to decrease the influence of wind on the construction safety screen 100. The application of ropes to stabilize construction safety screens is complicated for the construction workers. A lot of effort has to be put into the work of mounting the construction safety screens and the wind stabilizing ropes. The ropes have to be provided with anchoring points, and to be thoroughly tightened. A plurality of ropes are often necessary to stabilize a large construction safety screen. The stabilization provided to the construction safety screen is however limited. If the wind speed increases over a certain value, the wind load on the construction safety screen is hazardous and the construction safety screen must be folded to prevent the screen from being destroyed or dislodged from the construction building. Thus all the stabilizing ropes have to be released and the construction safety screen has to be folded. When the wind speed decreases again the construction safety screen is yet again unfolded and the stabilizing ropes have to be reattached to the anchoring points and thoroughly tightened.
In addition to the influence of the wind the construction safety screen often has to be frequently folded to provide working space for a crane or sky-lift or for allowing construction work on the building in the vicinity of the construction safety screen. Hence, the construction workers are forced to carry out the same procedure as described above for folding and unfolding the construction safety screen, which takes a lot of time and effort for the construction workers.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a wind lock device for stabilizing construction safety screens and a construction safety screen that alleviates the above-mentioned drawbacks of prior art technique.
This object is achieved by a wind lock device according to the present invention as defined in claim 1, and a construction safety screen comprising such a wind lock as defined in claim 9.
Thus, in accordance with a first aspect of the present invention, there is provided a wind lock device for stabilizing a construction safety screen such that it becomes less sensitive to wind loads. The safety screen comprises a fundament and a lever arm which is pivotally connected to said fundament at a first end portion of the lever arm. Further, the safety screen is operable between a folded state in which the lever arm is fully folded towards the fundament, and an unfolded state in which the lever arm is unfolded at a predetermined angle from the fundament. The wind lock device comprises a first bracket member having a first end portion and an opposite second end portion. The first end portion of the first bracket member is pivotally arranged at the lever arm. The second end portion is arranged to engage with the fundament of the construction safety screen. The device further comprises an operating member arranged at the second end portion of the first bracket member to allow lifting the second end portion of the first bracket member. In the folded state the first bracket member is fully folded towards the lever arm. In the unfolded state the second end portion of the first bracket member is unfolded towards and engaged with the fundament.
The wind lock device according to the invention thus provides a wind protection for the construction safety screen that is pivotally arranged at the construction safety screen lever arm. This arrangement of the wind lock allows for the wind lock to be folded and unfolded with respect to the lever arm, and the wind lock device is thus adaptable to the shape of the construction safety screen in the folded and the unfolded state, respectively. Furthermore, in the unfolded state the first bracket member provides a wind support by engaging with the fundament of the construction safety screen. The operating member provides a convenient way of lifting and thus folding the first bracket member when the user wants to fold the construction safety screen.
In accordance with an embodiment of the wind lock device, the first bracket member further comprises means for providing a predetermined angle between the lever arm and the first bracket member in the unfolded state. Thus, the pivotally arranged first bracket member may be fully folded along the lever arm in the folded state and is arranged to be limited to a predetermined angle when unfolded in the unfolded state. This allows for having a self extracting feature of the wind lock device such that when unfolding the construction safety screen, the wind lock device automatically unfolds and positions itself in the predetermined angle and engages with the fundament of the construction safety screen providing a wind lock.
In accordance with an embodiment of the wind lock device, the first end portion of the first bracket member is arranged to engage with the lever arm. This in combination with the first bracket member engaging with the fundament provides lateral stability to the construction safety screen such that it becomes less sensitive to side winds.
In accordance with an embodiment of the wind lock device, the means for providing a predetermined angle is a control rod arranged on a side of the first bracket member facing the lever arm, and located a predetermined distance from the pivot axle of the first bracket member, which provides a mechanically stable solution that is inexpensive and easy to manufacture.
In accordance with an embodiment of the wind lock device, the pivot axle of the pivotally arranged first bracket member is movably arranged in an oblong opening. This provides the advantage that the wind lock device is adaptable to the angle between the lever arm and the fundament of the construction safety screen.
In accordance with an embodiment of invention, the wind lock device further comprises a second bracket having a first and an opposite second end portion. The second bracket is arranged to encompass the lever arm. The second end portion of the second bracket member is engaged with the lever arm. The second bracket member provides a lateral reinforcement to the construction safety screen. Furthermore, the first and second bracket members are pivotally interconnected at their respective first end portions. The second lever arm is preferably shaped such that it also provides a mounting connection of the wind lock device to the lever arm, which is advantageous since the wind lock device is thus easily applicable to existing construction safety screens.
In accordance with an embodiment of the wind lock device, the operating member is a cord which is advantageous.
In accordance with an embodiment of the wind lock device, the operating member is a rope which is advantageous.
Furthermore, in accordance with a second aspect of the invention, there is provided a construction safety screen, comprising a fundament and a lever arm which is pivotally connected to the fundament at a first end portion of the lever arm. The safety screen is operable between a folded state in which the lever arm is fully folded towards the fundament, and in an unfolded state in which said lever arm is unfolded at a predetermined angle from the fundament. The construction safety screen further comprises at least one wind lock device according to the invention. Thus a construction safety screen is provided which has the additional advantages associated with the wind lock device as described above.
These and other aspects, features, and advantages of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail and with reference to the appended drawings in which:

Fig. 1 a) to c) are schematic side views of a prior art net support for a construction safety screen,
Fig. 2 a) is a schematic side view of a first embodiment of a wind lock according to the present invention which is mounted on a net support in an unfolded state, b) is a schematic perspective view of the first embodiment, and c) is a schematic side view of the first embodiment in a folded state,
Fig. 3 a) is a schematic side view of a second embodiment of a wind lock according to the present invention in an unfolded state, b) is a schematic side view of the second embodiment in a folded state, and c) is a schematic perspective view of the second embodiment;
Fig. 4 a) to c) are perspective views of a third embodiment of a wind lock device according to the present invention in a folded and an unfolded state, respectively;
Fig. 5 is a schematic perspective view of an embodiment according to a second aspect of the present invention; and
Fig. 6 is a schematic perspective view of an embodiment of a construction safety screen according to the present invention.

All the figures are highly schematic, not necessarily to scale, and they show only parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be explained in more detail in the detailed description below and the accompanying figures in which the numbers assigned to each feature designates the same feature throughout the description.
Referring to Figs. 2a)-c) a first embodiment of a wind lock device for stabilizing a construction safety screen. The wind lock is shown mounted on a device 200 comprises a first bracket member 201 having a first end portion 201 b and an opposite second end portion 201 a. The first end portion 201 b is pivotally arranged at the lever arm 102 of the net support 140. The second end portion 201 a is arranged to engage with the fundament 101 when the first bracket member 201 is fully tilted towards the fundament 101 in the unfolded state of the net support 140. This is realized by designing the first bracket member to encompass or fit to the fundament 101, see an exemplifying non limiting design in Fig. 2 b). The pivotal arrangement is in the exemplifying embodiment provided by mounting the first end portion 201 b onto the lever arm 102 utilizing a hinge 220 arranged on the side of the lever arm 102 which faces the fundament 101 in the folded state. The length of the first bracket member 201 and the positioning on the lever arm 102 of the pivotal arrangement of the first bracket member 201 is chosen as to arrange the wind lock at a substantially right angle with respect to the fundament 101 in the unfolded state, i.e. the wind lock is designed as to conform with the angle α of the net support 140.
The wind lock device 200 further comprises an operating member 205 arranged at the second end portion of the first bracket member 201 a. The operating member 205 has two functionalities. The first functionality is to allow the first bracket member 201 to be lifted and thus folded towards the lever arm 102 when raising the net support 140, and thus the construction safety screen 100, to the folded state. The second functionality is to, when going from the folded state of the construction safety screen 100 to the unfolded state of the construction safety screen 100, provide resistance enough for the first bracket member 201 to be pulled out from the lever arm 101 and to unfold and thus tilt over towards the fundament 101.
When going to the folded state, and having the operating member 205 realized with a rope 205, as in Fig. 2, the user simply pulls the rope 205 at the same time as the net support 140 is folded and secured. The folding of the construction net support 140 is done by, for instance, using a folding rope (not shown). The opposite side of the rope 205, which is not arranged at the second end portion of the first bracket member 201 a, is preferably attached on top of the fundament at the first end of the net.
When the net support 140 is unfolded, the folding rope is released and consequently the construction safety screen 100 is released and unfolded by means of its own weight. The rope 205 may then be used to pull back the first bracket member 201 in a controlled manner, which first bracket member 201 is thus released and tilted towards the fundament 101. However, it should be noticed that the first bracket member 201 is typically arranged with its centre of mass laterally displaced from the pivot axle 220, such that it is released and unfolded by means of its own weight as the net support 140 is unfolded.
A second embodiment of the wind lock device 300, as shown in Fig. 3, is arranged having means 306 for providing a predetermined angle β between the first bracket member 301 and the lever arm 102 in the unfolded state of the net support 140. A protrusion 306 is arranged at the first end portion 301 b of the first bracket member 301. The protrusion 306 is further arranged such that it faces and abuts the lever arm 102 in the unfolded state and prevents the first bracket member 301 from tilting further.
The first bracket member 301 according to the second embodiment as shown in Fig. 3 c) comprises two elongated elements, 301c and 301d, which are mounted a distance apart and in parallel such that the first end portion 301 b is arranged to engage with the lever arm. The second end portion 301 a engages with the fundament 101. Preferably, the distance between the two elongated elements, 301 c and 301 d, is chosen to be slightly larger then the thickness of the fundament 101 and the lever arm 102. In an alternative embodiment the two elongated elements of the first bracket member are shaped such as to allow for separate thicknesses of the fundament 101 and the lever arm 102.
In Fig. 3 c) the pivot axle 320 is arranged by means of a screw and a nut through holes 302 which are arranged in the first end portion of the two elongated elements, 301c and 301d, and a corresponding hole (not shown) through the lever arm 102. Furthermore, the holes 302 arranged in the two elongated elements 301 c and 301 d are oblong which allows the first bracket member 301 to slide. This means that the pivot axle 320 of the pivotally arranged first bracket member 301 is movably arranged. In turn this allows for a predetermined variation of the angle α of the net support 140.
In a third embodiment of the wind lock device, as shown in Figs. 4a - c), the wind lock device 400 comprises a first bracket member 401 and a second bracket member 410 having a first end portion (401 b, 410b) and an opposite second end portion (401 a, 410a), respectively. The first bracket member 401 and the second bracket member 410 are pivotally interconnected at the respective first end portions (401 b, 410b) such that a pivot axle 415 is formed. The first bracket member 401 is comprised of two elongated members, 401c and 401d, and the first end portion 401b of the first bracket member is arranged to engage with the first end portion of second bracket member 410b. The pivotal interconnection 415 is arranged by means of a bolt and a nut arranged in through holes 402 which are arranged in the first end portion 401b of the two elongated elements, 401c and 401d, and a corresponding hole pair arranged in the first end portion of the second bracket member 410b. Furthermore, the holes 402 arranged in the two elongated elements 401c and 401d are oblong allowing for the first bracket member 401 to slide. This means that the pivot axle 415 of the pivotally arranged first bracket member 401 is movably arranged. In turn this allows for a predetermined variation of the angle α of the net support 140.
In this third embodiment, the means for providing a predetermined angle β between the first bracket member 401 and the lever arm 102, and the second bracket member 410 in the unfolded state is a control rod 412 arranged on the side of the first bracket member which faces the fundament 101 in the folded state. The control rod 412 is furthermore arranged at a predetermined distance from the pivot axle 415 such that in the unfolded state, i.e. when the first bracket member 401 is folded towards the fundament 101, the control rod 412 abut against the second bracket member 410 and thus determines the angle β.
As is recognized by a man skilled in the art, there are alternative ways of arranging the pivotal interconnection in this and previously described embodiments by using a rivet, a threaded bolt or any other similar fastener.
According to a second aspect of the present invention, there is provided a construction safety screen 500 which comprises at least one net support 540 having a fundament 501 and a lever arm 502. The lever arm 502 is, in a first end portion of the lever arm 502, pivotally connected to the fundament 501. In this exemplifying example, as illustrated in Fig. 5, the construction safety screen 500 is arranged having two net supports 540. The construction safety screen 500 is operable between a folded state in which the lever arm is fully folded towards the fundament 501, and an unfolded state in which the lever arm 502 is un folded a predetermined angle from the fundament 501. The construction safety screen 500 further comprises a net 504 which sets the predetermined angle for the construction safety screen 500 when the lever arm 502 is fully unfolded. The construction safety screen 500 further comprises a wind lock 503 according to any of the previously described embodiments of the wind lock device according to the present invention.
In an alternative embodiment the construction safety screen 600 has a multi sectioned net. As an example the net comprises two sections, 604 and 605, as illustrated in Fig. 6.
Although the invention above has been described in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the scope of the invention as defined by the following claims.
It is to be noted, that for the purposes of this application, and in particular with regard to the appended claims, the word "comprising" does not exclude other elements or steps, that the word "a" or "an", does not exclude a plurality, which per se will be apparent to a person skilled in the art.

Claims

A wind lock device for stabilizing a construction safety screen, comprising a net support having a fundament and a lever arm which is pivotally connected to said fundament at a first end portion of the lever arm,
wherein said safety screen is operable between a folded state in which said lever arm is fully folded towards said fundament, and an unfolded state in which said lever arm is unfolded at a predetermined angle from said fundament, said device comprising:
a first bracket member having a first end portion and an opposite second end portion, wherein said first end portion of said first bracket member is pivotally arranged at said lever arm, and wherein said second end portion is arranged to engage with said fundament; and
an operating member arranged at said second end portion of said first bracket member to allow lifting said second end portion of said first bracket member;
wherein in said folded state said first bracket member is fully folded towards said lever arm,
wherein in said unfolded state said second end portion of said first bracket member is unfolded towards and engaged with said fundament.
A wind lock device according to claim 1, wherein said first bracket member further comprises means for providing a predetermined angle between said lever arm and said first bracket member in said unfolded state.
A wind lock device according to claim 2, wherein said means for providing a predetermined angle is a control rod arranged on a side of said first bracket member facing said lever arm, and located a predetermined distance from the pivot axle of said first bracket member.
A wind lock device according to any one of the preceding claims,
wherein the pivot axle of said pivotally arranged first bracket member is movably arranged in an oblong opening.
A wind lock device according to any of claims 1 to 4, wherein said first end portion of said first bracket member is arranged to engage with said lever arm.
A wind lock device according to any one of claims 1 to 4, further comprising a second bracket having a first and an opposite second end portion, wherein said second bracket is arranged to encompass said lever arm, wherein said second end portion of said second bracket member is engaged with said lever arm, and wherein said first and second bracket members are pivotally interconnected at said respective first end portions.
A wind lock device according to any one of the preceding claims,
wherein said operating member is a cord.
A wind lock device according to any one of the preceding claims,
wherein said operating member is a rope.
A construction safety screen, comprising a net, at least one net support arranged for supporting and stretching the net, wherein each net support comprises a fundament and a lever arm which is pivotally connected to said fundament at a first end portion of the lever arm, wherein said safety screen is operable between a folded state in which said lever arm is fully folded towards said fundament, and in an unfolded state in which said lever arm is unfolded at a predetermined angle from said fundament, said construction safety screen further comprising at least one wind lock device according to any of the previous claims.