WO2004048125A1

WO2004048125A1 - Screen tensioning system

Info

Publication number: WO2004048125A1
Application number: PCT/MK2002/000004
Authority: WO
Inventors: Goran Todoroski
Original assignee: Goran Todoroski
Priority date: 2002-11-01
Filing date: 2002-11-01
Publication date: 2004-06-10
Also published as: AU2002368396A1

Abstract

The proposed tensioning system is used for tensioning/tightening canvases and screens, meshes i.e. fences and other materials, with broad application in civil engineering, transportation vehicles and other means for transportation, advertising industry, publicbuildings (such as cinemas etc) or in the open - for providing large and even surfaces for projecting images. The system has a fixed part (4); movable part made up of solid iron (1) and screen carrier (2) and (3); then a tensioning device that is consisted of the elements (5)(6) and (7); and also a tensioning tube (8). With a simple turning of the bolt (6), it achieves lifting of the movable part and thus also the tensioning tube (8) together with the canvas or screen (10) around it. So generated tension forces are extremely large, and the employed tensioning tube (8) ensures uniform elongation of the canvas or screen along its entire length, therefore avoiding the danger of its local damage. The inventionalso enables execution of even stronger tensioning mechanisms, while the working distance can easily be adapted to the needs, trhough appropriate selection of the length of the bolt (6).

Description

SCREEN TENSIONING SYSTEM TECHNICAL FIELD

The system for tensioning of screens is an invention that finds touching points with a number of engineering fields and production intended for public consumption, starting from protective canvases/screens employed in means for transportation, partition screens-curtains for various buildings of private, social and public interest, through the industry for production of requisites and equipment for internal and outdoor promotion and advertising as well as fitting large screens for projections in cinema halls and premises for presentations, down to civil engineering for setting up prefabricated protective meshes i.e. safety fences during the execution of civil and building construction works in urban conditions and also for working out temporary safety fences between existing works.

BACKGROUND OF THE INVENTION

Various tensioning mechanisms are utilized with canvases and tarpaulins of the transportation vehicles and trailers. A characteristic of these mechanisms, which are widely used, is the fact that they provide only fast tensioning i.e. stressing of the canvas/tarpaulin, however there is not a possibility for adjusting the working distance, and also a deficiency is the fact that they provide only local elongation, that is to say the canvas/tarpaulin is pulled only at the spot of the tensioning device.

Another system for tensioning is employed with the narrow separation belts in public buildings (banks, department stores, airports) the speciality of which is in their very fast setting up since the tensioning mechanism is simple that is to say it is worked out through a self-tensioning spiral spring, however such a construction simultaneously provides only a minimum tensioning force.

In civil and building engineering they use various kinds of shackles, fasteners and similar simple means - mechanisms for tensioning, which are not able to provide any working distance despite generated large tensioning forces, while in the same time they are primarily oriented towards fixing i.e. fastening various elements.

Generally speaking, all so far known mechanisms or systems provide only local tensioning of the canvas or screen that easily comes at its corrugating and waving, while in the worst case also to its local durable elongation that is to say damage.

This invention essentially differs from all above-mentioned systems because it ensures fast and easy tensioning/stressing, by means of activating considerable tensioning forces, with a possibility for adjusting the working distance of the tensioning mechanism, and on the account of the simple construction it can attain relatively favourable production price. By means of a selection of an appropriate tensioning tube, it is possible to obtain uniform tensioning of the canvas or screen as well as simultaneous protection against its damage, which leads to overcoming the disadvantages of the other known systems and mechanisms.

OBJECT OF THE INVENTION

This patent solves the problem on the basis of an efficient fitting i.e. erecting and dismantling of canvases and screens, meshes or fences and other similar materials that could be coiled in a roll, and in the first place it solves the problem in all cases when the material has to be extremely strongly tensioned i.e. stressed. In the same time it solves the accompanying problem of the temporary or permanent elongation of the canvas or screen that occurs as a consequence of its intensive elongation, through providing appropriate working distance of the tensioning/tightening mechanism, which may alter if or when necessary. It is very important to achieve uniform tensioning of the canvas or screen along its entire length, and that is provided by using a stiff structural section or tube that is set back through a loop made in the canvas or screen itself.

BRIEF DESCRIPTION OF DRAWINGS

Fig.1 and Fig.2 show separately the constituent element of the movable part of the tensioning mechanism.

Fig.3 is a cross section of the movable part or the tensioning mechanism.

Fig.4 is a layout of the tensioning mechanism.

Fig.5 is a tensioning system where the screen and the load bearing structure also shown.

DISCLOSURE OF THE INVENTION The tensioning system is simple for manufacturing, with small dimension and weight and it is distinguished with simple incorporation. It is composed of two parts - tensioning mechanism and tensioning tube or tensioning profile, each of them described separately.

The tensioning mechanism consists of a fixed and a movable part, mutually interconnected with an active (working) bolt - tensioner, shown on drawings 1/2 and 2/2. It should be noted that, depending on the tensioning force that is required to be accomplished, modifications of the tensioning mechanism are possible - towards increasing or decreasing individual elements; however, in general, the concept of the mechanism does not change. In the text below it will be described a mechanism with a bolt of diameter016 mm (6), which falls into the mean size, in which the classification for the size of mechanism is defined precisely by the size of the active (working) bolt - tensioner, or indirectly, the required force of tensioning and the required working distance.

The moving part is presented on Fig.1 , Fig.2, Fig.3 and Fig.4. It is constructed of 3 constituent elements. The element (1) is solid iron of circular, hexagonal, rectangular or square form, with a dimension that is recommended to be double bolt diameter. Its minimum length should amount to 40 mm and in the middle there is a slotted screw thread corresponding to the bolt (6). Performed tests indicate that the quadrilateral forms (rectangular and square form) are the most appropriate since the movable part cannot rotate freely during tightening, and it is also simplified the connection of the remaining two elements (2) and (3) as supporting saddles of the tensioning tube (8) Their interconnection is realized by means of fillet welds with a preliminary preparation and grinding after welding, in accordance with the details (Fig.3 and Fig.4). So formed movable part has a width of 40 mm, which is optimum for this tensioning mechanism. In a case of a mass implementation of the system, it is possible for this part to be manufactured as an aluminium casting or to be extruded in a long strip with a section as shown on Fig.3, of which segments - parts with a width of 40 mm would be cut-out; they would undergo the necessary working up that is to say slotting or cutting of an adequate screw thread.

The fixed part along with the movable part and remaining elements of the system are shown on Fig.5. The load-bearing structure (9) upon which the fixed part , i.e. the whole tensioning mechanism is mounted, is presented in an arbitrary form. The fixed part consists of a cantilevered supporting saddle (4), which would be most economically to be worked out of an angle bar L50.50.5...80 as shown, or it could be adopted an adequate plate of a small thickness as a cantilevered overhang from the upper side of the load-bearing structure or else fastened in some other appropriate way. The cantilevered saddle(4) is drilled an opening without a thread with the same diameter as bolt (6), and in the direction of the same axis (13) there is also drilled an opening without a thread into the load-bearing structure (9). If there is a possibility, it is desirable for the two openings to be drilled as an assembly, that is to say after welding of the fixed part (4) to the load-bearing structure (9). If the thickness of the load-bearing structure (9) is under 3 mm, it is necessary to carry out local strengthening of the section prior to drilling, and also it will be necessary to elaborate suitable technology for welding of the fixed part to the load- bearing structure.

Both the fixed and the movable part, are mutually functionally interconnected with an active (working) bolt - tensioner (6) which has a thread along the entire length of the shank. Mounting is simple i.e. in the drilled openings of the fixed part we sink the bolt (6), , using also an appropriate flat washer (7) under the head of the bolt. Between the two fixed openings, by means of light coiling-up of the bolt, we install the movable part, which remains permanently trapped between the two openings. In order to prevent the bolt pulling-off from the lower opening, it is proposed to employ a weak spring (5), and in parallel with this task, the spring contributes for the movable part to be always in the lowest working position, which helps a lot in setting up of the tensioning tube (8), especially if we take into account that in addition to the shown position when the mechanism is up, it is also possible application of the mechanism from the bottom side or at the lateral side. The length of the bolt (6) should not be below triple highness of the movable part, and that is conditioned from the requirements for an appropriate tensioning-working distance (11) of the tensioning mechanism.

The tensioning tube (8) shown on Fig.5, is not firmly connected with the movable part. Its application is a great novelty and a significant step ahead in the technical solution of the problem of tensioning (stressing) canvases and screens. It is proposed utilization of a tubular structural section of an arbitrary form (circular, rectangular or hexagonal), and even an appropriate solid section. It can be worked out of different materials. Its stiffness i.e. load-bearing capacity, makes an influence in defining the number i.e. spacing of the tensioning mechanisms. Functioning of the system that requires minimum two tensioning mechanisms with a tensioning tube in between is rather simple. First of all, it is formed a loop (10') on the canvas or screen

(10) - by means of gluing, sewing, vulcanizing or other method, depending on the material of which the canvas or screen has been worked out. At the internal side of the loop there are made small openings at the places where the mechanism has to take on the tensioning tube. The movable parts of the mechanism are set up into the lowest position and the tensioning tube with drawn on canvas or screen is rested on them (Fig.5). Turning the bolt head (6) by means of an adequate wrench or spanner, it causes lifting of the movable part, in parallel with the axis (13) of the bolt. The unwanted rotation of the movable part is prevented because of the immediate vicinity of the movable part to the fixed part, while by means of its lifting, it also leads the tensioning tube (8') into working position shown with the dashed lines (8') on Fig.5 which thus elongates the canvas/screen.

The working distance (11) of the tensioning mechanism should not be below 20 mm (Fig.5).

There is a possibility for the working distance (11) to be increased in case of need, and that primarily depends on the dimensions of the canvas or screen in the direction of elongation as well as the material quality of the canvas or screen. However to increase the working distance

(11) of the mechanism, weak spring (7) could be replaced with an appropriate retaining ring under the load bearing structure (9).

The proposed working inclination (12) of the tensioning tube in relation to the head of load-bearing structure (9) as presented on Fig.5, could be altered, and it is also possible for it not to exist. It is mentioned once again that in case of need, the tensioning system, and especially the tensioning mechanism, can be modified through the use of stronger or weaker constituent elements, and thus to obtain the required tensioning force as well as the required working distance of the mechanism, at the most favourable price. The presented mechanism is of mean size and has an ultimate bearing capacity of 3000 N/mechanism, as determined with a trial testing by means of loading of worked out prototypes.

Claims

1. The system for tensioning/stressing canvases and screens consists of a fixed part (4); movable part formed of (1), (2) and (3); tensioner formed of the elements (5), (6) and (7); as well as a tensioning tube (8), characterized by the fact that turning of the bolt (6) causes lifting of the movable part together with the tensioning tube (8), and thus tensioning of the canvas or screen (10) is achieved.

2. The tensioning system as described in claim 1 enables easy movement of the movable part and the working force of tensioning of over 2000 N, characterized by the fact that a bolt (6) which has a thread along the entire length of the shank is used by means of whose turning it ensures unobstructed movement of the element (1) which is adequately slotted i.e. cut with a thread, and thus also to the other two elements (2) and (3) which are fixed to it.

3. The tensioning system described in the claim 1 enables variable working distance (11), characterized by the fact that it is possible to use bolts (6) with different length of the shank, and in case of need with an altered diameter and quality of the material. .

4. The tensioning system, in accordance with the claims 1 ,2 and 3, enables easy fitting and erection as well as dismantling i.e. disposal of the canvas or screen, characterized by the fact that the movable part is set up in the lowest working position, after which the tensioning tube (8) together with previously drawn on canvas or screen (10) is rested on it (or it is pulled out), whereas the tensioning tube (8) is not firmly connected with the movable part.

5. The tensioning system as described in the claim 1 enables a uniform force for tensioning the canvas or screen, characterized by the fact that the use of the tensioning tube (8) enables the locally generated tensioning force from the tensioning mechanism to be uniformly distributed along the entire length of the tensioning tube, in which purpose the stiffness of the tensioning tube as well as the mutual spacing of the tensioning mechanisms vary, depending on the required tensioning force for the canvas or screen.