GB2194271A

GB2194271A - Screen apparatus for a glass house

Info

Publication number: GB2194271A
Application number: GB08620703A
Authority: GB
Inventors: Frederick William Paton
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-08-27
Filing date: 1986-08-27
Publication date: 1988-03-02
Anticipated expiration: 2006-08-27
Also published as: GB8620703D0; GB2194271B

Abstract

A screen apparatus for a glass house comprising horizontal drums or rolls 14 supported on wires 16, a flexible sheet screen 15 secured to each drum or roll 14 and to fixed structure, each drum or roll 14 being provided with a sprocket 17 connected thereto via a free-wheel, a chain 18 engaged with the sprocket 17 having one end secured to fixed structure and its other end engaged with an endless drive wire or cable 19, said drive wire or cable 19 being wound around a tube 21 driven by a reversible motor 22 and each drum or roll 14 being connected to a weight 26. The arrangement is such that when the drive wire or cable 19 is driven in one direction each drum or roll 14, due to the weights 26, roll along the wires 16 to unroll the sheet screen 15 and when the drive wire or cable 19 is driven in the opposite direction the chain 18 rotates the drum or roll 14 in the opposite direction through the free wheel to cause the sheet screen 15 to be wound on the respective drum or roll 14. <IMAGE>

Description

SPECIFICATION Screen apparatus for a glass house This invention relates to a screen apparatus for a glass house, particularly, but not exclusively, for a glass house in which horticulture is carried out.

It is known to provide flexible sheet screens in a glass house which are movable between a stowage or inoperative position in which they lie horizontally adjacent to a vertical wall or row of roof support pillars or stanchons and an operative position in which they extend across the glass house beneath the roof from one vertical wall or row of pillars or stancheons to another wall or row of pillars or stancheons.

Such screens are used as thermal screens to prevent heat loss from the glass house or as screens to prevent sun-light entering the glass house through the roof section thereof.

It is usual for such screens to be pulled across the glass house between the stowage or inoperative position and the extended position. In the stowage or inoperative position the sheet screen material is loosely packed and takes up a considerable amount of space which restricts the area of glass house roof through which sun-light can pass to the plants.

There is a need for a screen apparatus in which the sheet screen material is tightly rolled onto a drum or roll in the stowage or inoperative position so as to take up the minimum amount of space.

According to the present invention there is provided a screen apparatus for a glass house, comprising a horizontal drum or roll, a flexible sheet screen having one end secured to fixed structure and its other end connected to said drum or roll, said drum or roll being provided with at least one sprocket connected to the drum or roll via a free-wheel mechanism, a chain engaged with said sprocket, one end of said chain being secured to fixed structure and its other end being engaged with a drive wire or cable, reversible drive means for moving the drive wire or cable across the glass house and means for applying a constant force to said drum or roll in one direction to cause it to move the drum or roll from a stowage or inoperative position across the glass house in said one direction when the end of the chain connected to the drive wire or cable is moved by said drive wire or cable in said one direction, to cause the screen to be unwound from the drum or roll, said end of the chain being moved in the opposite direction by said drive wire or cable when said drive wire or cable is driven in the reverse direction to drive the sprocket and said drum or roll through the free-wheel to cause the drum or roll to rotate and take-up the sheet material as it moves back to its stowage or inoperative position against said constant force.

Preferably the drum or roll is supported on wires extending across the glass house which also support the unrolled sheet screen.

The reversible drive means for the drive wire or cable may comprise a torque tube on which the drive wire or cable is wound and which is driven by a reversible motor. Alternatively the drive means for the drive wire or cable may comprise a rack to which the drive wire or cable is connected and a pinion driven by a reversible motor. The drive wire or cable may be driven by a chain engaged by a sprocket driven by a reversible motor.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic cross-section through a glass house provided with screen apparatus according to the present invention, Figure 2 is a horizontal section taken along the line 2-2 indicated in Fig. 1, Figure 3 is a diagrammatic perspective view of the screen apparatus, Figure 4 is a side view of a rack and pinion drive for the drive wire or cable, and Figure 5 is a diagrammatic side elevation of a claw device.

The glass-house is indicated generally at 10 and consists of vertical walls 11 and rows of vertical pillars or stancheons 12 which support pitched roof sections 13. The glass-house 10 is provided with screen apparatus which comprises a horizontal drum or roll 14 extending along each bay of the glass house 10. Each drum or roll 14 has connected t6 it one end of a flexible sheet screen 15 which has its other end secured to the adjacent row of pillars or stancheons 12 or adjacent wall 11.

The drums or rolls 14 and flexible sheet screens 15 rest on tensioned horizontal wires 16 which extend across each bay between walls 11 and pillars or stancheons 12. The wires 16 may be parallel and at right angle to the walls 11 or they may be at an angle so as to cross one another as shown in the drawings.

Each drum or roll 14 is provided at each end with a sprocket 17 which is provided with a free-wheel. Each sprocket 17 is engaged by a chain 18 and each chain 18 has one end fixed to fixed structure, such as the pillars or stancheons 12 or walls 11, and its other end connected to a common drive wire or cable 19 which extends acorss the glass house 10 just below the roof section 13. The drive wire or cable 19 is endless and passes around pulleys 20. One run of the drive wire or cable 19 is wrapped around a torque tube 21 which extends along the glass house 10 and which is driven by a reversible electric motor 22.

Alternatively, as shown in Fig. 4, the drive wire or cable 19 may be connected to each end of a rack 23 engaged by a pinion 24 driven by a reversible electric motor 25.

As another alternative the drive wire or cable 19 may be connected to a chain engaged with a sprocket driven by a reversible electric motor.

Each drum or roll 14 has a constant force applied to it in one direction by weights 26 connected to the drum or roll 14 by cable 27.

In the drawings the sheet screens 15 are shown partly unrolled.

The apparatus operates in the following manner.

If it is desired to unroll the sheet screens 15 and extend them across each bay of the glass house the electric motor 22 is operated so as to rotate the torque tube 21 in a direction such as to cause the drive wire or cable 19 to move in a clockwise direction as viewed in Figs. 1 and 3. In moving in this direction the ends of the chains 18 which are connected to the drive wire or cable 19 move in the same direction thus allowing the constant force applied by the weights 26 to move the drums or rolls 14 along the support wires 16, the drums or rolls 14 rotating due to the free-wheels provided in the sprockets 17 thus unrolling the sheet screens 15. The drums or rolls 14 will eventually lie against the opposite wall 11 or row of pillars or stancheons 12.

In order to roll-up the sheet screens 15 back onto the drums or rolls 14 the electric motor 22 is driven in the opposite direction and the torque tube 21 drives the drive wire or cable 19 in an anti-clockwise direction as viewed in Figs. 1 and 3. The ends of the chains 18 connected to the drive wire or cable 19 moves in the same direction and the chains 18 pull the drums or rolls 14 against the force of the weights 26 and the drums or rolls 14 are rotated through the sprockets 17 and free wheels in a direction to take-up the sheet screens 15. When the drums or rolls 14 come to rest close to a row of pillars or stancheons 12 or wall 11 the screen material 15 is wrapped tightly on the drums or rolls 14 and thus in the stowage or inoperative position take up little space and do not considerably restrict the passage of light through the roof sections 13.

In order to ensure that the sheet material 15 is evenly wound onto the drum or roll 14 it is possible to provide a claw or claws 28 which extend around the drum or roll 14 and has guide rollers 29 which contact the sheet material on the drum or roll 14, the or each claw 28 being connected by a line 30 to a weight 31 which provides a constant force in one direction to the claw 28.

It is also possible for the sheet material 15 to be provided with a filament or filaments which is or are wound with the material and connected to means, such as a weight, for producing a constant tension.

It will be appreciated that any suitable means other than weights 26,31 may be provided for producing a constant tension, such as spring means.

Claims

1. A screen apparatus for a glass house, comprising a horizontal drum or roll, a flexible sheet screen having one end secured to fixed structure and its other end connected to said drum or roll, said drum or roll being provided with at least one sprocket or pulley connected to the drum or roll via a free-wheel mechanism, a chain or belt engaged with said sprocket or pulley, one end of said chain or belt being secured to fixed structure and its other end being engaged with a drive member, reversible drive means for moving the drive member across the glass house and means for applying a constant force to said drum or roll in one direction to cause the drum or roll to move from a storage or inoperative position across the glass house in said one direction when the end of the chain or belt connected to the drive member is moved by said drive wire or cable in said one direction, to cause the screen to be unwound from the drum or roll, said end of the chain or belt being moved in the opposite direction by said drive member when the drive member is moved in the reverse direction to drive the sprocket or pulley and through said free wheel causes the drum or roll to rotate to take-up the sheet material as the drum or roll moves back to its storage or inoperative position against said constant force.

2. A screen apparatus as claimed in claim 1, in which the drum or roll is supported on wires extending across the glass house which also support the unrolled sheet screen.

3. A screen apparatus as claimed in claim 2, in which said support wires are parallel with each other and extend at a right angle to the drum or roll.

4. A screen apparatus as claimed in claim 2, in which said support wires extend at an angle to the drum or roll and cross one another.

5. A screen apparatus as claimed in any preceding claim, in which the reversible drive means comprises a tube driven by a reversible motor and the drive member comprises a wire or cable wound on said tube.

6. A screen apparatus as claimed in any one of claims 1 to 4, in which the reversible drive means comprises a rack and a pinion engaged with the rack and driven by a reversible motor and the drive member comprises a wire or cable connected to the rack.

7. A screen apparatus as claimed in any one of claims 1 to 4, in which the reversible drive means comprise a chain engaged by a sprocket driven by a reversible motor, and the drive member comprises a wire or cable con nected to the chain.

9. A screen apparatus as claimed in any preceding claim, in which the means for applying a constant force to the drum or roll comprise a weight connected thereto.

8. A screen apparatus as claimed in any one of claims 5 to 7, in which the drive wire or cable is endless and passes around pulleys.

10. A screen apparatus as claimed in any preceding claim, in which in order to ensure that the sheet material is evenly wound onto the drum or roll, a claw member extends around the drum or roll and has guide rollers which contact the sheet material on the drum or roll, said claw member being connected to a weight.

11. A screen apparatus as claimed in any preceding claim, in which a filament or filaments is or are wound with the sheet material and connected to means for producing a constant tension.

12. A screen apparatus as claimed in any preceding claim, in which there is provided a plurality of drums or rolls and a plurality of sheet screens and a common drive member and reversible drive means.

13. A screen apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.