GB2103266A

GB2103266A - Curtain sided vehicles

Info

Publication number: GB2103266A
Application number: GB08120167A
Authority: GB
Inventors: Barry Chapman
Original assignee: TRENDE TRANSPORT DESIGN LIMITE
Current assignee: TRENDE TRANSPORT DESIGN LIMITE
Priority date: 1981-06-30
Filing date: 1981-06-30
Publication date: 1983-02-16
Also published as: GB2103266B

Abstract

A vertically opening flexible curtain (14) for a curtain sided vehicle comprises a roller (20), endless chains (32) located at each side of the curtain secured to a curtain bar (16) at the lower edge of the curtain, the chains passing around wheels (34, 36, 38) and drive means for one of the upper chain wheels (34) and hence for raising or lowering the curtain. The chain wheel (34) is linked to the roller (20) via a torsion spring (50) which acts to produce tensioning of the curtain as the latter is unrolled from the roller, securing the curtain against billowing. <IMAGE>

Description

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SPECIFICATION Improvements in and relating to curtains for curtain sided vehicles FIELD OF INVENTION This invention concerns curtains for curtain sided vehicles particularly vertically opening curtains.

BACKGROUND OF THE INVENTION It has been proposed to provide a tubular member on which a curtain is wound inboard of the cant rail along the centre line of the body to give access through the sides of the then opened body and across the roof.

Another design involves a concertena or zig-zag curtain which can be folded for storage.

With all designs of vertically opening curtains, the problem of tensioning the curtain exists. In a design in which the curtain is wound inboard on a tube, the tube is rotated in one direction so that the curtain drops with gravity and after securing the bar in its lower position the drive can be reversed to tension the curtain.

A problem exists with this arrangement in that the curtain, in an intermediate position, can be caught by the wind and will billow out since the weight of the curtain bar along the lower edge will not always be sufficient to hold the curtain down.

A further problem is associated with the guiding of the edges of the curtain at the extremes of the opening. It is known to provide a 'C' shaped channel and nylon runners to guide and hold captive the edges of the curtain. Such rollers cause problems when the curtain is wrapped around the drum and have to be "pitched" correctly along the length of the edges of the curtain to prevent radial build up during winding of the curtain on the roller. Furthermore the curtain can still billow between the runners.

Where a concertina approach is employed, the edges cannot be guided because of width and load capacity limitations. If edge guides are to be used they tend to occupy precious space inboard of the vehicle or have to be mounted externally thus restricting the overall width of the load carrying part of the vehicle.

It is an object of the present invention to provide an improved design of vertically opening curtain for curtain sided vehicles.

SUMMARY OF THE INVENTION According to one aspect of the present invention a curtain for a curtain sided vehicle includes a curtain bar along or adjacent its lower edge and the latter is attached to chains at opposite ends which pass around toothed wheels at least one of which is driven and at least one of which transmits drive to a curtain tube around which the curtain can be rolled.

Preferably a torque storing device transmits drive between the last mentioned chain wheel and the curtain tube.

Preferably the torque storing device is a torsion spring and a difference in the average diameter of the curtain and the chain around the toothed wheel driving the curtain tube is selected so that if the chain travels L centimetres for N revolutions of the chain wheel, the curtain tube is forced to rotate (N + n) revolutions where n is typically one half a revolution where N is equal to the number of revolutions necessary to unwind the curtain fully.

In this way L centimetres of curtain can be unwound from the tube i.e. the mean curtain diameter is less than the mean chain diameter around the chain wheel.

Preferably the spring has a constant spring rate for the degree of twist corresponding to n revolutions. At the upper end the curtain may be provided with a seal and/or a cover over the upper end of the curtain may be resiliently biased into contact with the curtain.

Preferably the drive means for driving the toothed wheels and curtain tube are electric motors or hydraulic motors. Preferably means for controlling the drives are mounted close to the curtain opening.

Preferably a key switch is provided for security, the switch being operable by the vehicle ignition key or another key or by a security device.

The curtain may be of fabric or may be of a shuttered design.

Where the curtain tube is to be driven at one end only drive may be transmitted from that end to the other end by an axial which extends coaxially through the curtain tube from one end to the other.

According to another apsect of the invention there is proyided an improved closure device for a curtain sided vehicle which includes endless belt drive means at opposite ends of the curtain tube, the endless belt extending around driving wheels at least at one end and in part extending in line with the edge of the curtain and having fixed thereto opposite ends of a curtain bar extending across the lower end of the curtain wherein a torque storing device transmits drive between the endless belt drive means and the curtain tube and the difference in average diameter of curtain and endless belt drive means is selected such that if the chain and curtain travel L centimetres for Non revolutions of the endless belt drive, the curtain tube is forced to rotate (N + n) revolutions.

Preferably the torque storing device is a torsion spring.

Preferably the endless belt drive means is a chain drive.

Preferably the driving means around which the endless belt drive extends are toothed wheels.

Preferably drive is provided for the toothed wheels on both sides of the curtain.

According to another aspect of the invention an improved drive mechanism for a curtain sided vehicle comprises a curtain tube around which the curtain is rolled as the curtain is raised, drive means at least at one end of the tube for rotating the tube in one direction or the other, torque storing means between the drive means and the tube which allows the tube to rotate more or less than the drive means, an attachment between the lower free end of the curtain and endless belt drive means also driven by the said drive means rotating the curtain tube, the relationship between the drive to the endless belt and the drive to the curtain tube being such that during controlling of the curtain the curtain tube rotates by slightly less than the endless belt drive means for a given iinear movement of the attachment between the curtain and the endless belt, so that the curtain will be tensioned as the latter is unrolled.

Preferably the endless belt means is of an inextensible type and preferably comprises a chain around toothed wheels so that no slip can occur.

According to another aspect of the invention, there is provided a curtain sided vehicle fitted with a curtain tube around which the curtain can be rolled to give access to the interior of the vehicle, drive means to the tube at least at one end for rotating the tube to raise the curtain, endless belt means extending at least in part along the locus of the lower edge of the curtain as it rises and falls in the opening, the two endiess belts being attached to a curtain bar extending across and secured to the lower free edge of the curtain, the relationship between the drive to the curtain tube and the drive to the endless belt being such that the belt will move through a linear distance which is greater than the distance which the lower edge of the curtain would move for the same rotation of the drive means to the belt and curtain tube, and a torque storing device is provided for accommodating what would otherwise be a discrepancy between the movement of the belt and curtain, the torque storing device serving to tension the curtain as the latter is unrolled.

Preferably the endless belts are chains and drive is transmitted thereto through driven toothed wheels.

Conveniently a drive unit is provided at one end of the curtain tube and this serves to drive a toothed wheel and the curtain tube through a torque spring and a drive is transmitted to the opposite end of the curtain tube via a central freely rotatable co-axial driving axle on which is mounted another roothed wheel at the opposite end for driving the other chain at the opposite end of the curtain.

The invention will now be described by way of example with reference to the accompanying drawings in which~ Fig. 1 is a perspective view of a curtain sided vehicle fitted with a raisable curtain in accordance with the invention.

Fig. 2 is an end view in cross-section through the curtain on the line BB.

Fig. 3 is a vertical section through the corner post on the line AA.

Fig. 4 is a part horizontal section through the curtain tube (at the upper end) on the line CC, and Fig. 5 is a part horizontal section through the curtain beam at the bottom of the curtain on the line DD.

DETAILED DESCRIPTION OF DRAWINGS Fig.1 shows a typical lorry having a cab unit 10 and container section 12 one side at least of which is open and can be closed off by a flexible curtain generally designated 14 having a rigid lower edge or curtain beam 16 by which the curtain can be pulled on a downward direction to fully close the opening in the side of the container section 12 or can be raised in an upward direction to leave the opening unobscured.

Although not shown in detail, locking means may be provided at 18 openable by means of for example the vehicle ignition key whereby the curtain can be secured in its lowered position.

Similar locking means may be provided at the opposite end (not shown).

In Fig.2 which is a vertical section through the curtain on the line BB of Fig.4, the curtain 14 is shown extending in a broken manner (since the drawing it not to scale) between the curtain beam 16 and the curtain tube 20 around which the curtain is wrapped.

The curtain tube is contained within a shield 22 which is of a wrapover form so as to protect the curtain tube and form the top edge of the opening.

The shield 22 is secured to the upper edge of the cant rail 24 not visible in Fig.1 and the roof generaily designated 26 extends from the cant rail across the vehicle.

When the curtain is unwound the beam 16 cooperates with the side rave of the vehicle load carrying platform and is securable in position by means of a locking mechanism (shown only generally in Fig.1).

The two extreme positions of the curtain bar are shown at 16~(the lower most position) and at 16~~(the upper most position).

The curtain incudes a seal generally designated 28 which is of the type described in co-pending applications 8003270 and 8014901.

Fig.3 is a vertical section through the corner post on the line AA and demonstrates how the curtain bar 16 is attached to a number of sprockets 30 of a chain generally designated 32 which extends around a large chain wheel 34 at the upper end, a jockey pinion 36 below the large chain wheel and around a chain tensioning and return pinion 38 of the lower end. A chain tensioning device with adjustable nut 40 is provided at the lower end.

The chain wheel 34 is mounted on a drive shaft 42 which is carried in a bearing in a bearing housing 44.

Rotation of the chain wheel or its drive shaft results in movement of the chain 32 so as to move the curtain beam either in an upward or downward direction.

As shown in Fig.4 the chain wheel 34 is keyed to the drive shaft and the latter extends from a gearbox or from a hydraulic or electric motor drive (not shown) typically to the righthand side of the view shown in Fig. 4.

A thrust washer 46 is situated between the end face of the chain wheel 44 and the bearing housing 44 containing a dry bearing 48.

The curtain tube would be freely rotatable around the drive shaft 42 but for a tortion spring 50 one end of which is located in a driving recess 52 in the end face of the chain wheel 44 and the other end of which is secured in a second driving recess 54 in a spring arbor 56 attached to the curtain tube 20. The spring has a substantially constant spring rate over a deflection up to one revolution so that a constant tension will be exerted by the spring on the curtain 14 as the latter is unrolled. The tension arises from the difference in diameter of the chain driven toothed wheel 44 and the average diameter of the curtain around the curtain tube 20. By arranging that the curtain would normally travel a smaller distance than the chain for a given rotation of the chain wheel 44, so the spring becomes wound up and tensioned as the curtain is unrolled from the curtain tube.This tensioning of the curtain secures the latter against billowing.

Fig. 5 is a part horizontal section through the curtain beam at the bottom and illustrates the lower pinion 38 mounted on its own stub axle 58 by means of a dry bearing 60. Thrust washers are located at 60 and 62 to locate the pinion 38.

Fig. 5 demonstrates how the curtain beam 16 is attached to the sprockets by means of right angled brackets 64 and 66 which on the one hand are attached on opposite sides of a chain sprocket 68 and on the other hand are bolted to an extension of the chain bar.

The opposite end (lefthand end as shown in Figs. 4 and 5) of the curtain tube and curtain bar are similar to those shown in Fig. 4 and 5 but of opposite hand.

By extending the drive shaft 42 completely through the curtain tube, so a single drive unit is only required at one end of the shaft 42, a spring of opposite hand being provided at the opposite end and a similar sleeved bearing between the curtain tube and the drive shaft 42 so that the latter can protrude through the end of the curtain tube and provide drive to a second chain wheel at the opposite end. In the alternative, separate stub drive shafts such as 42 are provided at opposite ends of the curtain tube and each is separately driven by its own separate motor.

Claims

1. A curtain for a curtain sided vehicle, including a curtain bar along or adjacent its lower edge, respective belt means at each side of the curtain each belt means being secured with respect to the curtain lower edge and passing around wheels, at least one of the wheels being driven by drive means and at least one of the wheels being arranged to transmit drive to a curtain tube or rod around which the curtain can be rolled.

2. A curtain according to claim 1, wherein each belt means comprises a chain.

3. A curtain according to claim 2, wherein the chains are endless.

4. A curtain according to claim 2 or 3, wherein the wheels are toothed wheels.

5. A curtain according to any one of the preceding claims, further comprising a torque storing device for transmitting drive between the drive wheel and the curtain tube.

6. A curtain according to claim 5, wherein the torque storing device is a torsion spring.

7. A curtain according to claim 5 or 6, wherein the difference between the average diameter of the curtain when wound around the tube and the belt around the wheel driving the curtain tube is selected so that if the belt travels L centimetres for N revolutions of the belt drive wheel, the curtain tube is forced to rotate (N + n) revolutions where n is one half a revolution and where N is equal to the number of revolutions necessary to unwind the curtain fully.

8. A curtain according to claim 7, wherein the spring has a constant spring rate for the degree of twist corresponding to n revolutions.

9. A curtain according to any one of the preceding claims, further comprising a seal at the upper end of the curtain.

10. A curtain according to any one of the preceding claims, wherein a cover over the upper end of the curtain is resiliently biased into contact with the curtain.

11. A curtain according to any one of the preceding claims, wherein two drive means are provided for respectively driving wheels at opposite ends of the curtain tube.

12. A curtain according to any one of claims 1 to 10, wherein a single drive means is provided for driving a wheel at one end of the curtain tube, and drive is transmitted from that wheel to a wheel at the other end of the tube by means of an axial shaft which extends coaxially through the curtain tube.

13. A curtain according to any one of the preceding claims, wherein the or each drive means comprises on electric or hydraulic motor.

14. A curtain according to any one of the preceding claims, wherein control means for controlling the drive means are mounted close to the curtain opening.

15. A curtain according to claim 14, including security key switch means to permit activation and deactivation of the control means.

1 6. A curtain according to any one of the preceding claims, where the curtain is of fabric or is of shuttered construction.

17. A closure device for a curtain sided vehicle having a vertically opening curtain and a curtain tube, comprising endless belt means at opposite sides of the curtain, the endless belt means extending around wheels to maintain the belt means under tension, the belt means being fixed with respect to opposite ends of a curtain bar extending across the lower end of the curtain, drive means for at least one of the wheels for causing driving of the belt means, a torque storing device for transmitting drive between the endless belt means and the curtain tube, the difference in the average diameter of the curtain when wound around the tube and the belt round the driven wheel being selected such that when the belt and curtain travel L centimetres for N revolutions of the endless belt drive, the curtain tube is forced to rotate (N + n) revolutions.

18. A device according to claim 17, wherein the torque storing device is a torsion spring.

19. A device according to claim 16 or 17, wherein each belt means comprises a chain.

20. A device according to claim 19, wherein the chains extend around toothed wheels.

21. A drive mechanism for a curtain sided vehicle, comprising a curtain tube around which the curtain is rolled as the curtain is raised, drive means at least at one end of the tube for rotating the tube in one direction or the other, torque storing means between the drive means and the tube which allow the tube to rotate more or less than the drive means, an attachment between the lower free end of the curtain and endless belt means, said endless belt means also being driven by the said drive means rotating the curtain tube, the relationship between the drive to the endless belt means and to the curtain tube being such that during raising or lowering of the curtain the curtain tube rotates by slightly less than the endless belt means for a given linear movement of the attachment between the curtain and the endless belt means, so that the curtain will be tensioned as the latter is unrolled.

22. A curtain sided vehicle fitted with a curtain tube around which a curtain can be rolled to give access to the interior of the vehicle, drive means to the tube at least at one end for rotating the tube to raise the curtain, nedless belt means extending at least in part along the locus of the lower edge of the curtain as it rises and falls in the opening, two endless belts being secured with respect to the lower free edge of the curtain, the relationship between the drive to the curtain tube and the drive to the endless belts being such that the belts will move through a linear distance which is greater than the distance which the lower edge of the curtain would move for the same rotation of the drive means to the belts and curtain tube, and a torque storing device is provided for accommodating what would otherwise be a discrepancy between the movement of the belts and curtain, the torque storing device serving to tension the curtain as the latter is unrolled.

23. A vehicle according to claim 22, wherein the endless belts are chains and drive is transmitted thereto through a driven toothed wheel.

24. A vehicle according to claim 23, wherein a drive unit is provided at one end of the curtain tube and this serves to drive a toothed wheel and the curtain tube through a torque spring and a drive is transmitted to the opposite end of the curtain tube via a central freely rotatable co-axial driving axle on which is mounted another toothed wheel at the opposite end for driving the other chain at the opposite end of the curtain.

25. A curtain for a curtain sided vehicle substantially as herein described with reference to, and as shown in, the accompanying drawings.

26. A closure device for a curtain sided vehicle, substantially as herein described with reference to, and as shown in, the accompanying drawings.

27. A drive mechanism for a curtain sided vehicle, substantially as herein described with reference to, and as shown in, the accompanying drawings.

28. A curtain sided vehicle substantially as herein described with reference to, and as shown in, the accompanying drawings.