GB2540412A

GB2540412A - Polytunnel arrangement

Info

Publication number: GB2540412A
Application number: GB1512474.6A
Authority: GB
Inventors: Whatton Rolly
Original assignee: Haygrove Ltd
Current assignee: Haygrove Ltd
Priority date: 2015-07-16
Filing date: 2015-07-16
Publication date: 2017-01-18
Anticipated expiration: 2035-07-16
Also published as: WO2017009628A1; GB2540412B; GB201512474D0

Abstract

A polytunnel arrangement with a cover 16 supported upon hoop members 14, the cover partly secured to a rotatable bar 20, the bar rotating to wind cover material onto or from the bar 20, during such rotation the bar 20 translating/moving about a barrel roof tunnel profile 18 defined by the hoop members 14. The bar 20 is coupled to a drive shaft 24 by either a universal or flexible coupling 22. A support arrangement supports the drive shaft such that an end part of the shaft 24 remote from the bar 20 follows an arcuate path substantially matching the tunnel profile 18 during de-skinning. The drive shaft may be provided with means to secure it to a drive input, and the input may comprise an electric motor, a chain drive, or a hand crank. The support arrangement may be releasable, and may comprise one or more releasable clips.

Description

POLYTUNNEL ARRANGEMENT

This invention relates to a polytunnel arrangement, for example for use in the cultivation of crops such as soft fruits. However, it will be appreciated that the invention is not restricted in this regard and may be employed for other purposes. A polytunnel structure typically comprises a pair of rows of legs, each leg of one row being interconnected with a corresponding leg of the other row by a respective cover supporting hoop member. The hoop members together define a barrel shaped roof profile for the polytunnel structure. A flexible material cover is supported upon the hoop members and is anchored in position by a series of ropes, straps or the like which extend over the cover and are secured to, for example, the legs or to anchor points secured to the ground surface upon which the structure is located.

Often several polytunnel structures are arranged in a side-by-side fashion to as to provide shelter to an extended area, for example a field-scale area. In such an arrangement, the adjacent ends of hoop members of two adjacent polytunnel structures may be supported by a common leg, thereby reducing the number of component parts of the overall structure and minimising the spacing between adjacent polytunnel structures.

Where a structure of the type described hereinbefore is used in the cultivation of crops, there may be periods of time during which it is desired for the cover to be removed. For example, if no crops are located within the structure over the winter period, it may be desired to remove the cover in order to protect the structure from damage arising in the event of high winds or the like being experienced. The usual approach for de-skinning or removing the cover from a structure of the type described hereinbefore is time consuming, involving releasing and removing the anchoring ropes or straps and then manually rolling up the cover material from the edges of the tunnel structure towards the top thereof.

It is an object of the invention to provide a polytunnel arrangement in which the de-skinning operation is simplified, thereby overcoming or reducing the impact of the disadvantages associated with known polytunnel arrangements.

According to the present invention there is provided a polytunnel arrangement comprising a polytunnel structure including a cover supported upon a series of hoop members, the cover including a part secured to a rotatable bar, the arrangement further comprising a drive shaft coupled, via a universal or flexible coupling, to the rotatable bar to drive the bar for rotation to wind cover material onto or from the bar, the bar translating or moving about a barrel roof tunnel profile defined by the hoop members during such rotation, and a support arrangement arranged to support the drive shaft such that an end part thereof remote from the bar follows an arcuate path substantially matching the tunnel profile during de-skinning.

The said end part of the drive shaft may be provided with means to allow it to be secured to a drive input, for example in the form of an electric motor. However, other drive inputs may be used including, for example, chain drive arrangements, hand crank arrangements or other devices.

The support arrangement is preferably releasable, conveniently taking the form of one or more releasable clips whereby the cover material may be secured to the drive shaft.

Conveniently, a cross-bar is attached to at least one of the hoop members and which projects outside of the tunnel profile.

In use, rotation of the bar as a result of rotary movement of the drive shaft when support arrangement is active, the cover material being secured to the drive shaft, and the drive shaft and bar being substantially co-axial may result in the cover material being wound onto the bar and drive shaft, the bar and drive shaft both riding towards the top of the tunnel profile, riding upon the hoop members as a result of the cover material becoming wound onto the bar and drive shaft. During this movement, the end of the drive shaft remote from the bar substantially follows the tunnel profile. It will be appreciated that if a similar arrangement is provided to both sides of the tunnel structure, full de-skinning of the tunnel structure may be accomplished in a relatively simple and convenient manner. When de-skinned, it will be appreciated that the cover is wound upon two bars that are located to the top of the tunnel profile. If desired, once in this position, securing straps are the like may be used to secure them against movement.

It is often desired to be able to increase the ventilation of the interior of a tunnel structure, for example in order to allow control over the temperature and humidity therein. Conveniently, the structure described hereinbefore is able to perform this function in addition to serving to aid de-skinning. Preferably, in order to achieve this, the support arrangement is released, the end of the drive shaft remote from the bar conveniently then being supported by or adjacent the cross-bar.

In such an arrangement, when adjusting the level of ventilation, the drive shaft is driven to rotate the bar to wind cover material onto or unwind cover material from the bar, and as a result the bar rides upon the hoop members. The resulting change in angle between the bar and the drive shaft is accommodated by the universal or flexible coupling. The manner in which the end of the drive shaft remote from the bar is supported accommodates such angular movement of the drive shaft.

Where the support arrangement comprises one or more clips that can be used to secure part of the cover to the drive shaft, when the support arrangement is released the clips are preferably used to secure an edge part of the cover that is not to be removed to provide ventilation to one of the hoop members.

It will be appreciated that the invention as described hereinbefore is advantageous in that it allows de-skinning of a tunnel structure in a relatively simple and convenient manner, allowing de-skinning to be undertaken using relatively few workers. Where rotation of the drive shaft is motorised, then relatively little physical effort is required as part of the de-skinning operation.

Furthermore, the invention allows both de-skinning and ventilation control to be achieved and thus avoids the need to provide a separate ventilation control arrangement.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic end view illustrating a polytunnel structure in accordance with an embodiment of the invention;

Figure 2 is a view similar to Figure 1 illustrating the structure in a de-skinned condition; and

Figures 3 to 6 are diagrammatic side views of part of the polytunnel structure of Figure 1 in a range of conditions.

Referring to the accompanying drawings, a polytunnel structure 10 is illustrated that comprises a pair of rows of legs 12, each leg 12 of one of the rows being interconnected with a corresponding leg 12 of another of the rows by a respective hoop member 14. The hoop members 14 together define a barrel shaped roof profile 18. A cover 16, for example of a suitable flexible plastics material, is supported upon the hoop members 14 and is anchored in position by a series of ropes, straps or the like (not shown).

Whilst the drawings only illustrate a single structure 10, it will be appreciated that a number of such structures may be provided side-by-side in the conventional manner if desired.

In accordance with the invention, the edges of the cover 16 are secured to respective rotatable bars 20. Each bar 20 is connected via a respective universal joint or flexible drive coupling 22 to an associated drive shaft 24. To the end of the drive shaft 24 remote from the bar 20 is mounted an electric motor unit 26. Whilst a motor unit 26 is illustrated, is will be appreciated that the manner in which rotary drive is applied to the drive shaft 24 is not of particular concern to the operation of the invention and that the motor unit 26 could be replaced by, for example, a hand crank or a manually operated chain drive arrangement, for example, if desired.

In the arrangement shown, the cover 16 includes a cut-out in the region in which the drive shaft 24 is located. However, arrangements in which this is avoided may be possible.

As shown in the drawings, a cross-bar 28 is secured to an end one of the hoop members 14. The cross-bar 28 forms part of a frame that projects beyond the profile 18. An arm 30 pivotally interconnects the motor unit 26 and the cross-bar 28, the arm 30 serving to react torques generated upon the operation of the motor unit 26 urging the body thereof for rotation to the cross-bar 28 and thereby preventing rotation of the housing of the motor unit 26. A releasable support arrangement in the form of a series of releasable clips 32 (see Figure 5) is provided to support the drive shaft 24, when being used to de-skin the structure, such that a path followed by the free end of the drive shaft 24, ie the end thereof remote from the bar 20, is arcuate and substantially follows the barrel roof profile 18 of the structure. The clips 32, when serving to support the drive shaft 24 in the de-skinning mode of operation, are used to secure the lower edge of the part of the cover 16 adjacent the cut out to the drive shaft 24. However, when not being used in the de-skinning mode, the clips 32 are removed and may instead be used to secure the cover 16 to the end one of the hoop members 14 as shown in Figures 1, 3 and 4.

Figures 3 to 6 illustrate the structure in various modes or positions. Figure 3 illustrates the structure with the cover 16 in situ and with minimal ventilation. In this position, the bar 20 is adjacent a gutter of the structure. As the structure is not being used in a de-skinning mode, the clips 32 are released from the drive shaft 24 and instead are used to secure an end of the cover 16 to the end one of the hoop members 14. As shown, the drive shaft 24 is angled relative to the bar 20, but is rotationally coupled thereto by the universal joint 22, and the end of the drive shaft 24 remote from the bar 20 is resting upon the cross-bar 28.

From the position shown in Figure 3, if it is desired to increase the level of ventilation, the motor drive 26 is operated to drive the drive shaft 24, and hence the bar 20, for rotation, the arm 30 (not shown in Figure 3) serving to resist rotary motion of the motor body. The rotation of the bar 20 results in the edge part of the cover 16 becoming wound onto the bar 20, the bar 20 riding along the hoop members 14 substantially following the profile 18. During this movement of the bar 20, it will be appreciated that the angle of the drive shaft 24 relative to the bar 20 will change, this movement being accommodated by the universal joint 22. Throughout this movement, the end of the drive shaft 24 remote from the bar is supported by the cross-bar 28. Once the desired level of ventilation has been achieved, the motor drive can be switched off to terminate the rotation of the bar 20. Frictional resistance arising from the anchor ropes or the like that extend over the cover 16 serves to resist movement of the bar 20, and so retains the bar in position. However, if desired, a brake or the like may be included to resist rotation of the drive shaft 24 and/or bar 20 and thereby ensure that the desired level of ventilation is maintained.

Reducing the level of ventilation is achieved by rotating the bar 20 in the reverse direction. Figure 4 illustrates the arrangement in a maximum ventilation position.

If it is desired to de-skin the structure, then from the position shown in Figure 4, the clips 32 are removed from the end one of the hoop members 14, and the drive shaft 24 is lifted so as to lie alongside the adjacent lower edge of the cover 16 adjacent the cut-out. Once in this position, the drive shaft 24 is secured to the edge of the cover 16 using the clips 32. It will be appreciated that once in this position, the drive shaft 24 and bar 20 lie substantially coaxially. This position is shown in Figure 5. From this position, the motor unit 26 is operated to cause rotation of the drive shaft 24 and bar 20 with the result that the cover 16 becomes wound onto both the drive shaft 24 and the bar 20, the drive shaft 24 and the bar 20 riding over the hoop members 14 so as to substantially follow the profile 18 until they reach substantially the uppermost parts of the hoop member 14 as shown in Figures 2 and 6. In Figure 2, the motor units 26 and arms 30 are omitted for clarity.

Once in the de-skinned position as shown in Figures 2 and 6, the bars 20 and drive shafts 24 may be secured against movement, if desired.

From the position shown in Figures 2 and 6, re-skinning of the structure may be achieved simply by driving the drive shafts 24 and bars 20 in the reverse direction.

Depending upon the design of the polytunnel structure, it may be desirable or, in some case, necessary, to release or loosen the anchoring ropes or straps prior to de-skinning or re-skinning, and in some cases this may also be necessary prior to adjusting the degree of ventilation.

Whilst described as a combined vent and de-skinning arrangement, it will be appreciated that the invention is also applicable to arrangements in which no specific ventilation function is desired.

Whilst in the arrangement described hereinbefore the support arrangement takes the form of a series of releasable clips 32 operable to secure the drive shaft 24 to the cover 16 and thereby guide the end of the drive shaft 24 to substantially follow the arcuate profile 18, it will be appreciated that other arrangements may be possible. For example, the end part of the drive shaft could be guided for movement along an arcuate path by the arm 30 or a similar strut.

Where several tunnel structures are positioned side-by-side, it will be appreciated that each of them, or a number of them, may incorporate the above described features, thereby enabling de-skinning of all of the tunnels in a simple and convenient fashion.

Although one specific embodiment of the invention has been described herein, it will be appreciated that a wide range of modifications and alterations may be made to the specific arrangement described and illustrated without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS:

1. A polytunnel arrangement comprising a polytunnel structure including a cover supported upon a series of hoop members, the cover including a part secured to a rotatable bar, the arrangement further comprising a drive shaft coupled, via a universal or flexible coupling, to the rotatable bar to drive the bar for rotation to wind cover material onto or from the bar, the bar translating or moving about a barrel roof tunnel profile defined by the hoop members during such rotation, and a support arrangement arranged to support the drive shaft such that an end part thereof remote from the bar follows an arcuate path substantially matching the tunnel profile during de-skinning.

2. An arrangement according to Claim 1, wherein the said end part of the drive shaft is provided with means to allow it to be secured to a drive input.

3. An arrangement according to Claim 2, wherein the drive input comprises an electric motor.

4. An arrangement according to Claim 2, wherein the drive input comprises a chain drive arrangement or a hand crank arrangement.

5. An arrangement according to any of the preceding claims, wherein the support arrangement is releasable.

6. An arrangement according to any of the preceding claims, wherein the support arrangement comprises one or more releasable clips whereby the cover material may be secured to the drive shaft.

7. An arrangement according to any of the preceding claims, wherein a cross-bar is attached to at least one of the hoop members which projects outside of the tunnel profile.

8. An arrangement according to Claim 7, wherein when the support arrangement is released, the end of the drive shaft remote from the bar is supported by or adjacent the crossbar.