US3835603A

US3835603A - Means for covering the roof-like areas of supporting structures

Info

Publication number: US3835603A
Application number: US00127631A
Authority: US
Inventors: Fritz Schnebel
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-04-03
Filing date: 1971-03-24
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17
Also published as: FR2089015A5; SU648129A3; CA957815A; GB1288708A

Abstract

D R A W I N G
MEANS FOR COVERING THE ROOF-LIKE AREA OF A SUPPORTING STRUCTURE SUCH AS A STRETCHED CABLE NET COMPRISING A PLURALITY OF JUXTAPOSED SPACED COVER PLATES SECURED TO THE CABLE NET OR THE LIKE, A PLURALITY OF PERMANENTLY FLEXIBLE CONNECTOR ASSEMBLIES DISTRIBUTED OVER THE SURFACE AREA OF THE COVER PLATES AND SECURING THE COVER PLATES TO THE POINTS OF INTERSECTION OF THE CABLE NET AND PERMANENTLY ELASTIC SEALING STRIPS CAPABLE OF GIVING IN ALL DIRECTIONS AND CONNECTED TO THE EDGES OF THE COVER PLATES TO PROVIDE A WEATHER-TIGHT SEAL BETWEEN THE COVER PLATES.

Description

United States Patent 1191 Schnebel Sept. 17, 1974 15 MEANS FOR COVERING THE ROOF-LIKE 320.235 6/1885 Fricdrick 52/83 AREAS OF SUPPORTING STRUCTURES 3.363.383 1/1968 LaBarge 52/573 3.581.450 6/1971 Patry 52/403 Inventor: Fritz Schnebel, D820l e 3,611,649 10/1971 Muller 52/83 burg 75a, Post Frasdorf, Germany 3,643,391 2/1972 Mollingcr 52/83 [22] Filed: Mar. 24, 1971 FOREIGN PATENTS OR APPLICATIONS 211 pp No: 127 631 1,261,638 4/1961 France 52/403 Primary Examiner-Frank L. Abbott 1 1 Forelg" Application prlol'lty Data Assistant ExaminerH. E. Raduazo Apr. 3. 1970 Germany P 20 16089.8 Attorney, Agent, or Firm-H. Geoffrey Lynfield; Lester Horwitz [52] US. Cl 52/83, 52/573. 52/466,

52/468. 52/403, 248/9 [57] ABSTRACT [51] Int. Cl E04b 7/14 Mami for coverin 1 g the roof-llke area of a supporting [58] held of Search 52/83 7 structure such as a stretched cable net comprising a 52/584 248/21 l0 plurality of juxtaposed spaced cover plates secured to the cable net or the like, a plurality of permanently [56] References cued flexible connector assemblies distributed over the sur- U T STATES PATENTS face area of the cover plates and securing the cover 2.1 17.919 5/1938 Summers 248/21 plates to the points of intersection of the cable net and 3.302.260 2/1967 Cuddehack. 24/243 K permanently elastic sealing strips capable of giving in 2.051.064 8/19 52/544 all directions and connected to the edges of the cover 31139-531 4/1964 52/403 plates to provide a weather-tight seal between the 2.801.601) 8/1957 52/466 cover plate, 2.755.4114 7/1956 52/63 2.038.968 4/1936 8 Claims, 5 Drawing Figures Summers 248/21 PATENTED 3,835,603

SHEET 2 BF 3 Fig; 2-

PATENTEDSEP I 1 4 3', 8 35 603 SHEET 3 OF 3 MEANS FOR COVERING THE ROOF-LIKE AREAS OF SUPPORTING STRUCTURES The invention relates to means for covering the rooflike areas of a supporting structure formed by a stretched cable net or the like and consisting basically of a plurality of juxtaposed cover plates secured to the supporting cable net.

Such covering means, particularly when made from transparent material, are used for constructing roofs for sport arenas, exhibition halls and similar structures in which a weather-resistant covering of a large surface area is required. The cover plates are secured to the relatively light supporting means by screw connections or otherwise. 7

in known constructions of this type, the supporting means form a skeleton with substantially relatively fixed crossing points to which the cover plates may be secured. This means for instance where the supporting means are formed by a cable net, that the individual cables at the crossing points are rigidly connected to each other so that in practice there is no or only very little relative movement at these points of intersection. It is known to provide for this type of supports, cover plates with simple fastening means by means of which a reliable covering of the building construction can be achieved. The known fastening devices consist essentially of ball joints with suitable parts for fastening together the cover plates and cable nets. By virtue of the ball joints, the bending moments of the cover plates are to a large extent reduced or favourably distributed and a slight relative movement at the crossing points of the cable net is absorbed by the cover plates themselves.

More recently support means have been used in which the fastening points for the covering elements are relatively movable to each other. Where the supporting means are in the form ofa cable net, this means at the crossing points, the cables are no longer rigidly connected to each other but are flexibly supported with one another. In this way the setting up of stresses due to clamping at the points of intersection is avoided. The

Y advantage of such a cable net construction with varying angles at the points of intersection is in particular that wear and tear at these points of intersection caused by slight movement of the cables (even when the cables are rigidly connected) is avoided to a large extent since the cables are capable of moving easily relative to each other. Further, with such a movable supporting structure it is possible to obtain a better distribution of forces.

Such a movable construction of a supporting cable net results in that, under stress, the square areas formed by the cables assume a rhombic configuration in which opposed crossing points in any particular square are moved towards each other whilst the other two opposing crossing points are moved further apart. It will be appreciated that a rigid fastening of the cover plates to such a movable supporting structure is no longer possible as the angles between the cables are variable.

A covering of the type described furthermore will be subjected to uneven stresses caused for example by wind pressure and/or snow loads and different stresses which may be in tension and compression. In many instances the covered areas must be sufficiently strong to carry the weight of maintenance crew walking thereon. All such forces result in the supporting net-work being displaced as a result of which stresses are transmitted to the covering plates.

The object of the invention is to provide a covering means of the type described which can be used in connection with a supporting framework with relatively movable crossing points. In this way a covering is provided which is weather-resistant and also able to stand up to other stresses. These objects according to the invention are achieved by the provision of means for covering the roof-like area of a supporting structure such as a stretched cable net comprising a plurality of juxtaposed spaced cover plates secured to the cable net or the like, a plurality of permanently flexible connector assemblies distributed over the surface area of the cover plates and securing the cover plates to the points of intersection of the cable net and permanently elastic sealing strips capable of giving in all directions connected to the edges of the cover plates to provide a weather-tight seal between the cover plates.

The invention achieves that the cover plates are to some extent floating elastically with respect to the supporting net-work. In this way no excessive horizontal forces are transmitted to the cover plates so that any undesirable stresses therein are prevented. The individual cover plates can move relatively to one another and changes in the supporting net-work take place since the sealing means between edges of adjacent cover plates neither transmit stresses in tension or compression.

In a preferred embodiment of the invention, each connector assembly comprises a movable part to be screwed to the cable net, the cover plate embedded be tween two sealing rings being secured to the upper side of said part by means of a screw.

The oscillatory part of the connector assembly consists of a synthetic rubber buffer mounted between two steel plates. The two steel plates may be interconnected by a helical spring centrally arranged in the interior of the synthetic rubber buffer. This spring serves to prevent the oscillatory part from being excessively stressed.

In a preferred form of the invention, the sealing rings by which the cover plate is secured by means of a screw to the oscillatory part of the connector assembly, are clamped between an aluminium plate and the upper side of the oscillatory part. One of the two sealing rings may have a boss-shaped projection filling the screw hole in the cover plate and the two sealing rings may be made from synthetic rubber.

The oscillatory elements are suitably connected with the cable net by an additional, normally unstressed securing means. i

The sealing strips serving for joining the edges of the cover plates are made from weather-resistant artificial rubber and may also be translucent when translucent cover plates are used. The longitudinal edges of the sealing strips embrace the edges of the cover plates with U-shaped portions and are maintained in this position by clamping means. Holding strips having a U- section maybe slid over the longitudinal edges of the sealing strips which embraces the edges of the cover plates. Alternatively the longitudinal edges of the sealing strips which embrace the edges of the cover plates may be made of thickened U-shaped section.

The clamping means suitably each consist of two clamping jaws embracing the longitudinal edge of the sealing strips and may be held together under tension by screws lying next to the longitudinal edge of the cover plate. By the provision of longer clamping jaws, the butt joints between the upper clamping jaws may be offset with respect to the lower clamping jaws by about half their length.

The clamping means may consist each of a one-piece clamping part with two clamping jaws and a portion of reduced thickness between said jaws so that the clamping jaws embrace the longitudinal edges of the sealing strips and can be mutually tensioned by screws disposed alongside said longitudinal edges. This form of clamping means has the advantage of easy assembly.

The clamping means may extend in one piece along the full length of the cover plate and be provided with transverse slits at different places. This contraction has the advantage that the clamping pieces can be mounted easily on the full length of the cover plates without loosing the necessary flexibility.

To prevent or at least reduce snow and ice from entering the gap between cover plates we may provide cover plates or bridge pieces secured on one side to the edges on the outside of the cover plates.

Several constructional forms of the invention are shown in the drawings and will be described in greater detail in the following. In the drawings:

FIG. 1 shows a plan view of a cover plate mounted in accordance with the invention on its support means;

FIG. 2 shows a cross-section of the connector assembly for joining the cover plate to the supporting cable net;

FIG. 3 shows a cross-section through adjacent edges of two cover plates;

FIG. 4 shows modified means for joining adjacent edges of the cover plates; and

HO. 5 shows in perspective the joint formed between two adjacent cover plates.

FIG. 1 is a plan view of a portion of covering means constructed in accordance with the invention and shows its essential features. The covering means proper are in the form of a cover plate 1 made from transparent artificial resin, for example acrylic glass. Permanently elastic connector assemblies 2 are distributed over the surface of each acrylic glass plate and at its edges the cover plate is provided with flexible and permanently elastic sealing strips 3. FIGS. 2 and 3 show further details of the covering means.

The connector assembly, which is shown in section in FIG. 2, includes a vibration absorbing member preferably in the form of a buffer 4 made of synthetic rubber which is vulcanised between two steel plates 5 and 6. A helical spring 7 located inside the synthetic rubber buffer 4 provides an additional connection between the two steel plates 5 and 6. When the rubber buffer is subjected to tensile forces, these are effectively absorbed by thehelical spring 7. In this way there is overcome a disadvantage of a vibration absorbing member which is made entirely from artificial rubber which although able of absorbing compressional forces, have very little strength when subjected to tension. A small tear in the surface of the synthetic rubber would lead to the entire connector assemblyto be torn apart by reason of the small resistance of the rubber to tearing forces. The helical spring whichis vulcanised in the artificial rubber of the buffer thus relieves the artificial rubber when subjected to tensile forces. The helical spring prior to vulcanisation in the rubber buffer 4 can be welded to the steel plates 5 and 6 or can be connected thereto in some other manner.

On the side facing the cable support, the connector assembly has a screw 8 which extends through a hole in the lower steel plate 6 and can be screwed by means of a nut 9 with the cable net 10 forming the support means. On the other side of the connector assembly, which is remote from the cable net 10, two sealing

rings

11 and 12 made from artificial rubber are arranged on either side of the cover plate 1. The sealing rings 11 and I2 and the cover plate 1 located therebetween are clamped between an aluminium plate 13 and the lower steel plate 5. The clamping arrangement is effected by screwing in a centrally located screw 16 with the interposition of an aluminium disc 14 and a synthetic rubber disc 15. The tip of the screw engages in a nut 17 which is located in the rubber buffer 4 on the side facing away from the cable net 10 with the screw passing through a hole in the steel plate 5.

The outer sealing ring 12 is centrally formed with a boss-shaped portion 18, the outer diameter of which corresponds to the hole in the cover plate 1 and which in height corresponds to the thickness of the cover plate. This boss 18 projects through the cover plate and ensures that the screw bolt 16 does not come into direct contact with the cover plate I. As a result the forces on this part of the connector are uniformly distributed.

The described connector elements permit a balanced movement of the support means and avoid unnecessary tension at the points of intersection of the supporting cables without subjecting the cover plate to undue stress. By selecting the diameter, height and quality of the synthetic rubber of the buffer, the connector assembly can be constructed in such a manner that horizontal forces transmitted to the cover plate, do not exceed a given amount when the connector elements are subject to large displacement. In this manner, horizontal forces set up in the main plane of the cover plates can be kept within tolerable limits and damage to the plates is prevented. Further, the connector assembly is capable of sustaining forces in tension and compression caused by the weight of the cover plate, snow loads, the action of the wind and also the weight of maintenance crew which might be walking on the cover plates.

Forces in compression can be absorbed without diff culty by the synthetic rubber buffer 4 which forms part of the connector assembly. In order that the connector assembly is also capable of taking tensile forces, the helical spring 7 is vulcanised between steel plates 5 and For safetys sake, in the event of destruction of the connector assembly, provision may be made of additional connecting means which connect the connector assembly with the supporting member but which are normally not subjected to any stress. These additional means may consist of a tension hook arranged on the cable net, which is joined to a recessed receiver formed in one of the steel plates 5.

The cable net on which the cover plates are held by means of the connector assemblies has normally a square configuration but when subjected to load may assume a rhombic configuration. The connector asse mblies absorb most of the forces before transmitting them to the cover plates. The cover plates are not only displaced parallel to each other but a twisting of the cover plates about their vertical axes takes place with the formation of trapezoidal gaps therebetween. In addition there will be relative displacements of the individual cover plates in their main planes as a result of flexibility of the synthetic material from which the cover plates are made. The sealing strips at the gaps between the cover plates must therefore be flexible and permanently elastic in all directions in order not to offer resistance of such movements as otherwise undesirable tension would be set up in the cover plates.

In FIG. 3 such a sealing strip is shown in section. This sealing strip consists of thin sheet material made from weather-resistant synthetic rubber and this should particularly be resistant against ultra-violet radiation. Further this strip with its longitudinal edge is bent double to embrace the edge 19 of the cover plate. Over this is placed a U-shaped holding strip which is held in clamping relationship between upper and

lower clamping jaws

21 and 22, which are secured together by means of screws 23. The members of this clamping connection are constructed in such a manner that when loosening the screws 23, the

jaws

21 and 22 are opened up and thus can be easily moved over the U-shaped holding strip 25. The screws 23 need not be provided with sealing means since they do not penetrate the seal formed by the sealing strip.

The parts of the clamping assembly may be composed of short clamping pieces which, when viewed in plan, are arranged in the form of a parallelogram to distribute the stress on the clamping assembly. Gaps between the individual clamping pieces are necessary so that a flexible chain of clamping pieces is formed along the edges of the cover plates which are then free to move out of their main planes.

The parts of the clamping assembly shown in the drawing include large clamping pieces in the form of rails or

jaws

21 and 22 whose length roughly corresponds to the distance between the points of intersection of the cable net. The butt joints formed between adjacent jaws 21 on the one side of the cover plate are relatively staggered with respect to the butt joints formed on the other side by about half the length of the clamping pieces, this again preventing the formation of undue stress in the cover plate. The provision of gaps between the clamping pieces results in a chain-like arrangement which permits relative movement of the clamping pieces on the formation of the cover plates without permanent structural deformation of the clamping pieces. The resistance offered by the individual clamping pieces must be such that the maximum load imposed thereon does not create any permanent deformation and the seal of the clamping assembly is maintained under stress.

The clamping assembly forming the two jaws may also be made in longer pieces which are formed with notches or the like of reduced thickness at those points where relative motion of the clamping jaws is required. In this way again relative movement of the clamping pieces is possible under a slight amount of tension. This form of the clamping pieces has the advantage of being easily mounted since before assembly the jaws remain splayed apart and no additional steps are required to cause the jaws to open up in this fashion.

Such one-piece clamping pieces may extend for the full length of the edge of the cover plates. It is however, necessary here to provide transverse slits at various points along the length of the clamping pieces so as to permit bending of the clamping pieces under stress. However, these slits or indentations do not extend through the entire cross-section of the clamping pieces which would remain in one piece. The transverse slits or indentations may be provided in the upper and the lower clamping jaws at the area of reduced thickness and even both jaws may be so formed.

' The sealing strips 3 is clamped to the cover plate in a water and air-tight manner. At the transverse joints of the cover plates and also at right angles to the edge joints, the individual pieces of the sealing strip are connected to each other by welding or vulcanisation.

Since the sealing strips do not transmit any substantial forces at right angles or parallel to the edge 19 of the cover plate 1, it is necessary to arrange a connector assembly immediately next to the edge of the cover plates in order to transmit forces, which will be set up, from the cover plate to the support means and vice versa. The support of the edges of the cover plate may also be obtained by the provision of transverse members which bridge the gap between adjacent cover plates and which are permanently attached to one of the edges and guided in stirrups on the other edge.

FIG. 4 shows a modified constructional form of the sealing means shown in FIG. 1. The sealing strip 3 is here formed in one piece with the U-shaped holding strip 25, this simplifying assembly. The gap between adjacent cover plates is, in addition, covered by a bridge piece 24 which will be described in greater detail below. The sealing strip 3 can be extruded in one piece with the holding strip 25.

The sealing of the longitudinal edges 20 of the sealing strip 3 with edges 19 of the cover plate is not required, since the sealing strip only transmits minimum forces and the clamping action between jaws and cover plate is sufficient to provide adequate sealing. Further, when laying out the cover plate it is not absolutely necessary that their edges are precisely equi-distant from each other since the elastic nature of the sealing strips compensates for slight differences in spacing.

FIG. 5 shows in perspective parts of a joint between adjacent cover plates constructed according to the invention. In this arrangement, a bridge piece 24 is provided which is secured on one side of the joint by means of screws 23 to one of the clamping jaws whilst the other side of the bridge piece is free to slide over the corresponding part of the clamping connection on the other cover plate. By the provision of an overlapping arrangement of such bridge pieces the accumulation of ice and snow in the gaps between the cover plates is prevented to a large extent and excessive loading on the sealing strip is prevented. Since the bridge pieces are secured only on one edge, no force is transmitted from one cover plate to the other. This means that the flexibility of the sealing strip 3 is in no way affected.

Where three cover plates are arranged so as to form a T-shaped joint therebetween or where four cover plates are mutually arranged to form a cross-shaped joint, the sealing strip 3 is formed with a suitably shaped depression so that here again the relative mobility of the cover plates and the flexibility of the sealing strip is ensured.

I claim:

1. An improved weather-resistant roof-like covering for sport arenas, exhibition halls and similar large structures comprising a stretched cable net forming a support with relatively movable crossing points, a plurality of juxtaposed spaced cover plates resting upon and secured to said cable net, a plurality of permenently flexible connector assemblies distributed over the surface area of each of the cover plates and extending therethrough and securing the cover plates solely at the points of intersection of the cable net, and permanently elastic strips capable of giving in all directions connected to the edges of the cover plates to provide a weather-tight seal between the cover plates.

2. An improved connector assembly for securing juxtaposed cover plates to a stretched cable net forming part of a roof-like covering for large structures comprising a movable rubber buffer to be secured to the cable net at a crossing point, a steel plate on either side of that ruber buffer, a sealing ring on either side of said cover plate also located at said crossing point, screw means securing said sealing rings and the cover plate embedded therebetween to one of the steel plates in contact with said rubber buffer and spring means within said rubber buffer to provide the only other connection between said steel plates on each side of said rubber buffer.

3. An improved roof-like covering for large structures comprising a stretched cable net support, spaced cover plates resting on and secured to said cable net, permanently flexible connector assemblies securing said cover plates to said cable, weather-resistant flexible sealing strips joining the edges of adjacent cover plates, opposite edges of the sealing strips embracing adjacent edges of adjacent cover plates with U-shaped portions and separate clamping means for maintaining opposite longitudinal edges of the sealing strips in position and U-sectioned holding strips slid over the longitudinal edges of the sealing strips embracing the edges of said cover plates.

4. Roof-like covering as in claim 3, wherein the longitudinal edges of the sealing strips which embrace the edges of the cover plates are made of thickened U- shaped section.

5. Roof-like covering means according to claim 3, wherein the clamping means each consist of two clam ping jaws forming butt joints embracing the longitudinal edges of the sealing strips and are held together under tension by screws disposed next to longitudinal edges. the sealing strips not being penetrated by the screws.

6. Roof-like covering means according to claim 5, wherein by the provision of longer clamping jaws the butt joints between the upper clamping jaws is offset with respect to the lower clamping jaws by about half their length.

7. Roof-like covering means according to claim 3, wherein the clamping means consist each of a onepiece clamping part with two clamping jaws and a portion of reduced thickness between said jaws so that the clamping jaws embrace the longitudinal edges of the sealing strips and can be mutually tensioned by screws disposed alongside said longitudinal edges, the sealing strips not being penetrated by the screws.

8. Covering means according to claim 7, wherein the clamping means extend in one piece along the length of the cover plate and are provided with transverse slits at different places.