US3640296A

US3640296A - Pavilion with mechanism for automatically controlling sag and tension

Info

Publication number: US3640296A
Application number: US67712A
Authority: US
Inventors: Carl F Huddle
Original assignee: TENSION STRUCTURES Co
Current assignee: HOTTEL Corp A CORP OF
Priority date: 1970-08-28
Filing date: 1970-08-28
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08

Abstract

A tentlike structure, hereinafter called a ''''pavilion,'''' which includes two arches inclined away from each other at acute angles to the vertical and mounted so that they may be swung about their leg ends toward and away from this position and moved bodily toward and away from each other, a membrance of which one end is attached to each of the arches, and means for automatically sensing departures of the tension and/or the sag in the membrane from the desired values and moving the arches to correct them.

Description

nited States Patent 1 3,640,296 Huddle Feb. 8, 1972 [54] PAVILION WITH MECHANISM FOR 3,461,890 8/1969 Goodrich ..l35/l R AUTOMATICALLY CONTROLLING 3,465,764 9/1969 Huddle ..l35/l R SAG AND TENSION Appl. N0.: 67,712

ILS. (II. ..135/ 4 R Int. Cl 1/347 Field ofSearch.... ..l35/1,4

References Cited UNITED STATES PATENTS V l -lorton Primary ExaminerPeter M. Caun Attorney-A. F. Baillio [57] ABSTRACT A tentlike structure, hereinafter called a pavilion," which includes two arches inclined away from each other at acute angles to the vertical and mounted so that they may be swung about their leg ends toward and away from this position and moved bodily toward and away from each other, a membrance of which one end is attached to each of the arches, and means for automatically sensing departures of the tension and/or the sag in the membrane from the desired values and moving the arches to correct them.

9 Claims, 5 Drawing Figures aledozse WFWWE mm INVENTOR.

CARL F HUDDLE also PATEEWEU FEB 81972 SHEET E 0? 2 INVENTOR. CARL F. HUDDLE PAVILION WITH MECHANISM FOR AUTOMATICALLY CONTROLLING SAG AND TENSION BACKGROUND OF INVENTION This invention relates to pavilions, especially pavilions like those disclosed in my US. Pat. No. 3,215,153, dated Nov. 2, 1965 and others of my patents and applications, which include two supports of which at least one is an arch inclined away from the other and mounted so that it may swing in either direction from this position and an inelastic flexible membrane which extends between the supports and is attached to them. Particularly, the invention relates to means for minimizing variations in the tension and/or sag in the membrane from the desired values upon changes in atmospheric conditions, stretching, shrinkage of the membrane or the load on the membrane so as to minimize flutter of the membrane and consequent damage to the structure.

While the spring-loaded tiedowns 20 in my US. Pat. No. 3,465,764, dated Sept. 9, 1969, do this to some extent, they do not in some structures serve the purpose as well as the expedients disclosed in this application.

SUMMARY OF INVENTION The principal object of this invention is to provide mechanisms which will better maintain the tension and/or the sag in the membranes of the structures under consideration at the desired values despite changes in conditions so as to minimize flutter of the membranes and consequent damage to the structure.

For a better understanding of the nature and objects of the invention, reference is made to the following specification and the accompanying drawings wherein preferred embodiments of the invention are described and shown:

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. I is a perspective view of a pavilion which is equipped with tension and sag control mechanism in accordance with the invention;

FIG. 2 is an enlarged view of the control mechanism with which the pavilion shown in FIG. 1 is equipped;

FIG. 3 is perspective view of a pavilion which is equipped with another form of tension and sag control mechanism in accordance with the invention;

FIG. 4 is an enlarged view of the control mechanism with which the pavilion shown in FIG. 3 is equipped.

FIG. 5 is a view of another device for sensing variations in the tension and/or sag in the membrane and actuating the control mechanism with which the pavilion shown in FIG. 4 is equipped.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pavilion shown in FIGS. 1 and 2 of the drawings includes two arches l inclined away from each other at acute angles to the vertical and mounted on the ground or other base 2 so that they may be swung about their leg ends toward and away from this position. Between the arches 1 extends a tailored membrane 3 of woven fabric, plastic or plastic-coated fabric of which one end is attached to each of the arches in any suitable manner. The membrane is preferably prestretched so that it is substantially inextensible in both directions and may be self-supporting or supported on cables which extend between the arches.

The ends of the pavilion may be closed by tailored walls 4 of the same material as the membrane and attached in any suitable manner to the arches 1. In this event, the bight ends of the arches are tied down and the membrane 3 tensioned to the desired extent by fastening the lower ends of the end walls 4 to anchors embedded in the base 2. Alternatively the ends or, as shown in the drawing, one end of the pavilion may be left open. In this event, the arches or arch may be tied down and the membrane 3 tensioned by cables 5 attached to the arches and to anchors embedded in the base 2.

To minimize automatically variations in the sag in the membrane from the desired value upon changes in conditions and in the tension therein upon changes in conditions other than the load on the membrane, the ends of the legs of one or both of the arches 1 are mounted on the shorter arms of levers 6. The levers 6 in turn are mounted to swing on brackets 7 mounted on the base 2.

The longer arms of the levers 6 are urged in the direction to move the arches bodily and angularly outwardly and upwardly and maintain the tension and sag in the membrane and end wall at the desired values by springs 8. The springs 8 are seated on the longer arms of the levers and encircle rods 9 which are anchored to the base 2 and extend through the longer arms of the levers. To adjust the load of the springs and thus the tension and sag in the membrane and end wall cranks 10 are threaded on the upper ends of the rods.

The springs 8 will, of course, tend to maintain at the desired values the sag in the membrane due to changes in condition and the tension therein due to changes other than load. Excessive sag in the membrane due to load on the membrane or any other condition may be eliminated by adjustment of the load on the springs 8 by means of the cranks 10.

The pavilion shown in FIGS. 3 and 5 is itself like'that shown in FIGS. 1 and 2 but the mechanism for minimizing automatically variations in the tension and sag in the membrane from the desired values upon changes in conditions has been modified so that it is basically sag responsive rather than tension responsive. This mechanism, therefore, maintains the sag at the desired value whether the change is due to changes in tension or changes in load and maintains the tension approximately constant if there is no change in load.

In FIGS. 3 and 4, the ends of the legs of one or both of the arches l are mounted to swing between the ends of levers 11 whose lower ends are in turn mounted to swing on the base I. The other ends of the levers 11 are connected to pistons 12 which slide in cylinders 13 and may be actuated by fluid to regulate the tension and sag in the membrane 3.

Fluid is supplied to the cylinders 13 from a reservoir 14 by a pump 15 operated by an electric motor 16 through pipelines 17 and 18. In the pipeline 17 from the reservoir to the pump is installed a check valve 19 which prevents the pump returning fluid to the reservoir. In the pipeline 18 from the pump to the cylinders is installed a check valve 20 which prevents return of fluid from the cylinders to the pump. To prevent the sag in the membrane 3 from being reduced below the desired value and thus the tension in the membrane from being increased to a greater value than is necessary to maintain the sag at the desired value, there is provided a return pipeline 21 from the pipeline l8 to-the reservoir 14 in which is installed a solenoidoperated valve 22 which opens when the sag in the membrane is reduced to the desired value and thus prevents the tension in the membrane being increased to a greater value than the sag at the desired value is necessary to maintain.

To sense changes in the sag and in the tension in the membrane 3 as measured by the sag, there is provided a band 23 with a spring 24 in it which is looped around the membrane and fastened to the base 2 at both ends. In the band 23 there is also installed a switch 25 with a fixed or movable contact connected by a lead 26 to one side of a source of electricity. The switch is also provided with a movable or fixed contact on one side of the first-mentioned contact connected by a lead 27 to one side of the motor 16 so that if the sag in the membrane exceeds a certain value the switch will be closed and energize the motor and restore the sag and the tension in the membrane 3 to their original values unless the increase in sag was due to load on the membrane in which event the tensions will be increased beyond its original value. i

In the switch 25, there is provided a second movable or fixed contact which is connected by a lead 28 to one side of the solenoid so that when the sag decreases below a selected value, fluid will be returned from the cylinders 13 to the reservoir 14 through the pipeline 2! and the sag, consequently, increased and the tension reduced.

Instead of the band 23 to sense variations in the sag and thus in the tension in the membrane 3 and actuate the switch 25, there may be provided, as shown in FIG. 5, in the membrane 3 or end wall 4 a tension ring 29 which consists of a cable 30 in a curved pocket 31. The ends of the cable are connected to a beam 32 which is connected to the base 2 by a link 33 and a spring 34. In the link 33 or between the link and the spring 34, there is installed a switch 25 like that shown in FIG. 3 and similarly connected to the source of electricity, the motor 16 and the valve 22.

Increase in the sag in the membrane 3 will introduce slack into the membrane and, unless the sag is due to an increase in load on the membrane, also into the end wall 4 and a decrease in sag will increase the tension therein so that the tension ring 25 will serve the same purpose as the band 23 except that when it is installed in the end wall, it will be basically responsive to variations in tension rather than to variations in sag.

To make springs 8 and the sensors 23 and 29 irresponsive to momentary changes in the sag or tension in the membrane 3 or end wall 4, suitable damping means may be associated with the switches 25.

Iclaim:

1. In a pavilion, a support mounted on the ground or other base, an arch which is inclined away from the support and mounted so that it may swing toward and away from the support, a membrane whose one end is attached to the support and whose other end is attached to the arch, a tiedown attached to the arch and the base, means sensitive to departures in tension and/or sag in the membrane from selected values, and means actuated by the sensor to correct for departures from the desired values of the tension and/or the sag.

2. The pavilion claimed in claim 1 in which the sensor includes a switch and the actuator includes an electric motor.

3. The pavilion claimed in claim 1 in which the actuator includes a motor and means for transmitting force from the motor to the membrane.

4. The pavilion claimed in claim 3 in which the transmission includes a hydraulic system and means to bleed fluid from the transmission when the pressure exceeds a selected value.

5. The pavilion claimed in claim 1 in which the sensor includes a band which follows the contour of the membrane.

6. The pavilion claimed in claim 1 in which the sensor includes a member which is attached to one of the tiedowns and the membrane.

7. In a pavilion, a support mounted on the ground or other base, an arch which is inclined away from the support and mounted on the base so that it may swing and move bodily toward and away from the support, a membrane whose one end is attached to the support and whose other end is attached to the arch, and means for automatically sensing and moving the arch to correct for departures from the desired values of the tension and/or the sag in the membrane, including a lever which is mounted to swing on the base and carries the arch and to which the means for moving the arch is connected.

8. The pavilion claimed in claim 7 in which the means for moving the arch includes a spring.

9. In a pavilion, a support mounted on the ground or another base, an arch whose bight is disposed at a distance from the support, a membrane whose one end is attached to the support and whose other end is attached to the arch, means sensitive to departures in the sag in the membrane from a selected value, and means activated by the sensor to correct for departures from the selected value of the sag in the membrane.