GB2163725A - Winding and re-winding unit for covers, canopies and other sheet materials - Google Patents

Abstract

A sheet roll (16) and line winding drums (4A,4B) are driven from the same shaft. To unwind the sheet, pulling lines (14A, 14B) are wound on the drums which are each clutched to the shaft. To re-wind the sheet, the shaft is reversed, the drums being declutched to free-wheel on the shaft. The roll (16) back rotates, driven by the shaft vice a sprag clutch enclosed within the roll. The clutches (19) clutching the drums (4A,4B) to the shaft have an annular friction device (19) between their faces (3.1,3.2) to brake the back rotation of the drums to tension the lines and sheet during sheet re-wind. <IMAGE>

Description

SPECIFICATION Improvements to winding and rewinding unit for covers canopies and other linear materials This invention relates to the winding and unwinding of interrelated and interconnected rollers and or drums that transport sheet, strip and cable and cord to and from a linear plane to a spirally wound form. The uses are wide and varied and include, carpet displays, covers of equipment, machinery, sports fields, awnings, screens, canopies pools, tanks and the reeling of cord, cable and rope. When such materials are wound from one roller or drum onto another, a differential speed is created as each layer of material is wound to a spiral form, each revolution results in an increased diameter related to its thickness.It is normal practice to provide differential speed devices, multiple driving motor/units and clutch mechanisms to perform these operations and keep the material under light tension in the linear and spiral planes. This invention eliminates the need for differential speed control, multiple driving motors/units and muliple clutches, together with the associated complicated control circuitary. In the specification of my Application No.84 11584 (Serial No. ) I have described and claimed a winding and rewinding unit for covers, canopies and other linear materials.The present invention provides another improved form of such a unit where the function of overcoming the differential speed of winding and rewinding a sheet or rope like material on and off a roller remains unchanged, but new features are embodied as follows: According to the present invention, a single speed geared motor unit with forward and reverse drive has a shaft passing through the winding drum and keyed to the clutch with a housed radial bearing mounted on a further extension of the shaft that now carries the winding roller. A free wheel or sprag clutch unit is interposed at the point where the shaft meets, and is connected in turn to the main roller body. Sheet like materials are attached to the roller at one end and to a towing bar at the other end.One or two ropes or cables (hereafter called lines) are attached to the tow bar and led along the path to be travelled by the covering sheet.

At the limit of the travel path, the lines pass around idling pulleys and transverse back to roller position, pass around further idling pulleys, so their path is directed onto the winding drum or drums. It is an essential feature of the invention that the covering sheet roller is always of greater diameter than the winding drum, to ensure that the rotational speed of the roller is less than the winding drum. This allows the free wheel/sprag clutch to always run free when the covering sheet is being towed and unwound off the roller. Also the cover sheet and tow lines must be kept under constant tension during the winding and unwinding operations.For a better understanding of the invention, reference should be made to the accompanying drawings, although a far more detailed description and drawings, which shows a form of winding and rewinding unit to which the present invention may be applied, reference should be made to the Complete Specification and drawing of aforesaid application No.84/11584 (serial No.

Referring to the drawing sheet 1. Fig. 1.1.

of present application, the tensioning devices 19. is interposed between the opposing conical faces of the clutch mechnism 3. The tensioning device 19. is constructed of a resilient and friction contact property providing type of material and may be circular or vee shaped in its cross section. By selection of its annular as well as its chordal diameter or dimensions, various torque/tension forces can be imparted to the opposing inward facing conical faces of the clutch mechanism components 3.1 and 3.2 According to a prefered feature of this invention, the tensioning device 19. that keeps the cover and tow lines taut, is now integrated with the clutch mechanism. It also functions as a dust and moisture seal to the clutch mechanism whilst retaining its primary function of providing the torque/tension requirements to the cover and tow lines.Secondly, the sprag clutch or free wheel 6. is now housed within the main roller so that it provides: 1. A self centreing assembly.

2. Compensation for ovality of the bore of the roller.

3. Reduces the overall length of the drive unit.

4. Seals the sprag clutch or free wheel from the Ingress of dust and moisture.

5. A cusioned drive to offset the effects of the suddenly applied loads, imparted by activation of the clutch mechanism that drives the main roller.

6. A shear pin protection devices 22. for excessive torque loadings.

The friction between the faces 3.1. and 3.2.

and the tensioning device 19. is thus increased and supplements the grip of the clutch mechanism 19. When the clutch mechanism is disengaged, it provides a resistance between the inward faces 3.1. and 3.2.

The winding drum 4 is now free to revolve on the common line shaft 8, but is prevented from allowing the tow line 14. to become slack by the aforesaid friction imparted by the tensioning device 19. and the friction set up between the conical faces of 3.1. and 3.2.

Secondly, there is a sealing action imparted by the contacting surfaces of the tensioning device 19 and the conical faces of 3.1 and 3.2.

thus preventing the ingress of dust and moisture into jthe drive faces of the clutch mecha nism 3.

The second improvement to the invention is now described. The Sprag Clutch or free wheel 6 is now housed in the main roller 16 within the body of the coupling 17 incorporating the bearing 7 previously located externally.

The main roller 16 is centralised and assembled onto a combined, bearing, sprag clutch or free wheel assembly 6,7 by the interference fit of two resilient rings 20. The positive drive from the sprag clutch or free wheel being a series of countersunk screws positioned around and through the periphery of the main roller 16 into the combined coupling 17. A water and oil proof shroud 21 encapsulates the spring clutch or free wheel 6. but is free to revolve around the line shaft 8 when the winding drum 4 is engaged and the tow line 14 is pulling the rolled up canopy, cover or other linear material off of the main roller 16.

Thus, the general assembly of the unit drawing sheet 1. has been reduced to the proportions shown on drawing sheet 2.

A further reduction in the assembled length of the drive unit has been made by mounting the drive motor 1 above the reduction gear box 2 but is not necessarily a feature of this present invention.

The two resilient rings 20 provide ease of assembly, and obviate the need for a close tolerance bore of the main roller 16 and also allows for ovality within that bore thus eliminating expensive machining of the parts.

The second function of the resilient rings 20 and the shroud 21 is to seal the sprag clutch or free wheel assembly 17 from the ingress of dust and moisture. This is of paramount importance when the unit is used for wet areas or wet conditions. A general feature of the invention is that the clutch 3 is an Electro Mechanical unit and is energised by an electrical interlock with the drive motor 1 in a manner which engages the clutch faces 3.1 and 3.2. whilst the motor is driving in one direction and is de-energised and disengaged when the drive motor 1 is reversed and driving in the opposite direction.

A further improvement of the complete drive unit as described in my Patent Application No. 11584 (serial No ) that incorporates the aforesaid improvements, is to incorporate a winding drum 4A and 4B each end of the canopy roller 16. The output shaft 18 is continued or attached to a continuation of that shaft through the centre of the canopy roller and the winding drum 4B is positively fixed to the driving plate of a second Electro mechanical clutch unit 3B. When the clutch faces 3.1. and 3.2. are engaged, the winding drums 4A and 4B thus commence winding the tow lines 14A and 14B simultaneously. The tow lines 14A and 14B are attached to the extreme end and edges of the canopy transverse support bar 13.Thus the space transversed by the canopy 15 and/or tow bar 15 is kept completey free of the towing lines 14, 14A, 148. and allows for much more compact and space saving installations. Also, the tirque output value to the winding drum 4A and 4B and the resistance value of the tensioning devices 19A, 19B are both doubled in value. The use of two winding drums, clutches and tensioning devices is of particular value for longer or larger canopies.

A further extension of this feature is that for even larger and longer canopy winding and unwinding installations, a further motor and gear box can be incorporated with wind-winding drum 4B tensioning device 19B and clutch 3B.

All other functions and elements of the drive unit are contained in my Application No.84/1184 (serial No.

All features of the double winding drum and double power drive and gearbox are shown on drawing No. 3.

Claims (7)

1. A tensioning device for use with winding and rewinding units for covers, canopies and other linear materials that is incorporated with a clutch mechanism, so that the cover and tow lines remain taut when the clutch mechanism is disengaged.

2. A tensioning device that aids the torque transmitted by a clutch mechanism when the clutch is engaged.

3. A tensioning device according to claim 1 and 2 that prevents the ingress of dust and moisture when the clutch mechanism is engaged and disengaged.

4. A Sprag clutch or free wheel unit that is installed within the main roller of the cover, canopy or linear material so that it provides the functions of:

4.1 Preventing ingress of dust and moisture.

4.2 The retention of lubricant and grease.

4.3 Reducing the size of the drive unit for winding and rewinding canopies, covers and linear material.

4.4 As a cushion to the intial start up torque to drive the main roller.

5. The incorporation and inclusion of all the above claims 1 to 4, within the body of our complete specification No.84/11584 (Serial No

6. A double winding drum version incorporating and including all the above claims 1 to 4, utilising a single drive motor and gear box, within the embodiment of my complete specification No.84/1184 (serial No

7. A double winding drum version incorporating and including all the above claims 1 to 4 utilising two drive motors and gearbox, within the embodiment of my complete specification No.84/1184 (serial No.