This invention relates to an improved roll support spindle and has been devised particularly though not solely for, the support of rolls of continuous material during any process requiring rotation of the roll.

BACKGROUND ART There are many situations where it is desired to support a roll or reel of continuous sheet material such as paper, plastic film or foil material, either for dispensing of material from the roll or for winding onto the roll. Such rolls commonly have tubular cores formed, for example, from paper, plastic or metal tubing and are generally supported for rotation on a spindle in the apparatus concerned. The roll is supported on the spindle in a number of different ways, depending on the application. For example, the spindle may be provided with cones at either end thereof, one cone being fixed and the other cone being axially movable to support the roll between the cones in a wedging action and centralise the roll on the spindle. Other forms of support spindles have been provided with a number of longitudinal slats having studs protruding inwardly therefrom through the wall of the support spindle to a central actuating device adapted to move the slats outwardly and, hence, increase the circum¬ ference of the support spindle to lock the core thereon. Yet another form uses a rotationally cast membrane of elastomeric material such as polyurethane. Repairs to rotationally cast polyurethane membranes are almost impossible to effect and have to be returned to the original manufacturer for a complete recast. Another disadvantage wi h this type of spindle is that a standard cannot be established because of the variation of the wall thickness of the support spindle, which has to be either increased or decreased depending on load factors and therefore affecting the elastic properties of the

membrane.

These known methods of mounting a roll onto a spindle are either complex and, therefore, expensive to manufac¬ ture and prone to breakdown in use, or are cumbersome and time consuming to use, requiring considerable operator effort and taking up valuable process time. It is therefore the object of the present invention to provide an improved roll support spindle which will obviate or minimise the foregoing disadvantages in a simple yet effective manner, or which will at least provide the public with a useful choice.

DISCLOSURE OF INVENTION

Accordingly the invention consists in a roll support spindle comprising a hollow tubular axle adapted to be rotatably supported by suitable bearings, end plugs at or towards either end of the axle forming a fluid tight chamber therein, a plurality of circular threaded apertures in the tubular wall of the axle between the end plugs, a plurality of screw inserted elastomeric membranes sealing the apertures, and fluid supply means adapted to pressurise the interior of the hollow tubular axle, causing the elastomeric membrane to expand outwardly through the apertures.

Preferably the elastomeric membrane is formed by com¬ pression or injection . moul ding and when screwed into the apertures finishes substantially flush with the external surface of the tubular axle when the interior of the hollow tubular axle is not pressurised. Preferably the fluid means comprise an air supply and release valve in one of the end plugs.

BRIEF DESCRIPTION OF DRAWINGS

Notwithstanding any other forms that may fall within its scope, one preferred form of the invention will now be described by way of example only with reference to the accompanying drawings in which:- Fig. 1 is a longitudinal cross section through an inflated roll support spindle according to the invention. Fig. 2 is a transverse cross section on line A-A of Figure 1, deflated and with core removed.

MODES FOR CARRYING OUT THE INVENTION

In the preferred form of the invention, a short roll support spindle adapted to be cantilevered from a single set of bearings is constructed as follows, although it will be appreciated that the spindle may be made of any desired length and may be supported by bearings at either end thereof.

The roll support spindle comprises a hollow tubular axle 1 "in which is inserted end plugs 2 and 3. The end plugs form a fluid-tight chamber 4 within the hollow tubular axle. The roll support spindle is adapted to be rotable supported by suitable bearings and is conveniently provided with a journal 5 which may form an extension of the end plug 3. In the alternative any other suitable form of bearing support may be provided.

A plurality of circular apertures 6 are formed in the circumferential wall of the hollow tubular axle 1, equi- spaced around the circumference of the axle. The ciVcu ^' lar apertures 6 are provided with a suitable standard screw thread 7.

An externally threaded hollow plug 8 containing an elast¬ omeric moulded membrane 9 is screwed into the circ.ular apertures 6 and sealed with a suitable sealant, forming a fluid tight chamber 4. The threaded plug 8 and the elastomeric membrane 9 are then machined so as to finish flush with the outside diameter of the hollow tubular axle 1. The end plug 2 is provided with a fluid supply means adapted to pressurise the interior of the hollow tubular axle 1 causing the elastomeric membrane 9 to expand out¬ wardly through the hollow plug 8.

In the preferred form of the invention, the fluid supply means comprises an air supply and release valve 10 axially located in the end plug 2.

In use when it is desired to support a roll of material on the roll support spindle according to the invention, the roll core 11 is engaged over the roll support spindle until it is positioned in the desired axial location. Compressed air is then supplied through the valve 10 into the interior chamber 4 causing the elastomeric membrane 9 to expand outwardly through the hollow plugs 8 as shown at 12. The expanded elastomeric membrane automatically centralises the roll core 11 on the roll support spindle and securely holds the roll core locked tightly in place on the spindle ready for rotation. Once the material has been exhausted from the roll core, air pressure is released from the chamber 4 through the valve 10 allowing the elastomeric membrane to return to its normal position flush with the outer surface of the tubular axle 1 allowing the roll core 11 to be simply removed from the roll support spindle.

In this manner, a roll support spindle is provided which is simple and economical to manufacture, reliable in use, easily maintained, and which enables an operator to quickly and simply engage or remove a roll core from the spindl e.