Roll handling equipment
The present invention relates to roll-handling equipment and provides an expanding chuck for use in such equipment especially, but not exclusively, in the paper industry. 
     Paper and certain other web materials for industrial use usually are stored in the form of large rolls in which the web material is wound about a hollow cylindrical core or is wound about a mandrel which is subsequently removed to leave a core-less roll (i.e. one in wich the innermost windings constitute a core). As used hereinafter, the word &#34;core&#34; includes the innermost windings of a core-less roll unless the context clearly implies otherwise. During the winding of a roll for storage or its subsequent unwinding for use, it is necessary to support the core for rotation about its longitudinal axis. Such support is provided by chucks engaging the inner surface of the core. These chucks can be mounted on or integral with a rotatable shaft extending, for example, through the core. Alternatively, the chucks are shaftless in that they are carried by respective rotatable flanges or the like disposed adjacent the ends of the core so that the chucks extend into and engage the core immediately adjacent said ends. 
     Various designs of chuck are presently available but none are entirely satisfactory, especially for use with relatively soft cores such as those of cardboard, paper or fibre. The problems frequently encountered with known chucks include splitting of the core with consequential damage to web material in the innermost windings and failure to provide adequate engagement with the core to prevent slipping of the roll during braking by the chuck. Chucks presently in use include non-expanding tapered chucks, air expanding chucks, centrifugally expanding chucks and so-called &#34;tilt-lock&#34; chucks in which spring actuated teeth extend from the chuck body to engage the core. 
     It is an object of the present invention to provide an expanding chuck of relatively simple mechanically-operated design which will at least reduce the risk of encountering the problems referred to above. 
     According to the present invention therefore, there is provided an expanding chuck for engaging the inner surface of a hollow cylinder, which chuck comprises 
     A ROTATABLE BODY HAVING PERIPHERALLY SPACED AXIALLY EXTENDING SUPPORT SURFACES INCLINED TO THE AXIS OF ROTATION; 
     A PLURALITY OF CYLINDER-ENGAGING ELEMENTS ABUTTING AND MOVABLE AXIALLY OVER SAID SUPPORT SURFACES BETWEEN A RADIALLY INNER CONFIGURATION AND A RADIALLY OUTER CONFIGURATION TO ENGAGE THE INNER SURFACE OF THE CYLINDER; 
     AN ACTUATING MEMBER ACTING ON SAID ELEMENTS TO MOVE THEM AXIALLY OVER THE SUPPORT SURFACES BETWEEN SAID RADIALLY INNER AND OUTER CONFIGURATIONS; AND 
     SPRING MEANS BIASSING SAID ELEMENTS AXIALLY INTO THEIR RADIALLY INNER CONFIGURATION. 
     In use, the chuck of the invention is inserted into the cylinder with the cylinder-engaging elements maintained in their radially inner configuration under the bias of the spring means. The actuating member is then moved to expand the elements towards their radially outer configuration into engagement usually, but not necessarily, frictional, with the inner surface of the cylinder. The said member is maintained in position to retain the elements in such engagement until it is desired to remove the chuck, whence the actuating member is released allowing the elements to return to their radially inner configuration under the spring bias. 
     The novel chuck has particular application to the handling of rolls of web material and hence it is preferred that the chuck should be adapted to fit in and engage the cores of such rolls. Usually such cores have an internal diameter of 3 or 4 inches and accordingly said preferred chucks are suitably dimensioned for use with one or the other of said core diameters. 
     The body of the chuck can be adapted for mounting on a shaft or can be integral with a shaft. In the case of a through shaft, an axially spaced pair of chucks usually will be provided. The body can alternatively be adapted for so-called &#34;shaftless&#34; operation by for example, provision of flange, stub-shaft or integral shaft mountings. Said means of mounting a chuck are known per se for existing chucks and the chuck of the invention can be adapted for use in an analogous manner to existing chucks. It is preferred however that the body should be adapted for connection in a shaftless mill roll stand. 
     The body can be of any shape but preferably is cylindrical. It is preferred also that the support surfaces are constituted by the bases of axially extending keyways (i.e. grooves) peripherally spaced about the body. Those bases suitably are planar and tangential to the axis of rotation. The support surfaces are inclined to the said axis and diverge therefrom in an axial direction either away from or, preferably, towards the axially outer end of the body with respect to the intended position of the chuck within the cylinder to be engaged. 
     The cylinder engaging elements are movable axially over the support surfaces and preferably are of generally triangular shape in axial cross-sections so that the radially outer (i.e. cylinder engaging) surface of each element extends axially of the body throughout movement between the radially inner and outer configurations. Said radially outer surfaces can be smooth or irregular, e.g. fluted, to increase frictional engagement with the inner surface of the cylinder to be engaged. Preferably, that surface is part-cylindrical of a radius substantially equal to the internal radius of said cylinder. It is preferred also that the elements are equally spaced circumferentially of the axis of rotation and are four or six in number. 
     The actuating member can be an annular member slidably received on the body for axial movement relative thereto. In such a case, the cylinder-engaging elements can be adapted to engage the annular member for axial movement therewith at least in the direction of the radially outer configuration of said elements. For example, the annular member can have a radially extending recess or groove in which a radially extending projection of each cylinder-engaging element is located. Conveniently, the actuating member is adapted to abut the end of the cylinder to be engaged and to be retained thereby whilst the body of the chuck is moved further into the cylinder. 
     The spring means can act directly on the cylinder-engaging elements or on the actuating member and can comprise helical compression springs acting between said element or member and the body. 
    
    
     The following is a description by way of example only and with reference to the accompanying informal drawings of a chuck in accordance with a preferred embodiment of the present invention. In the drawings: 
     FIG. 1 is a front perspective view of a shaftless chuck for use with a shaftless mill roll stand for unrolling rolls of paper; 
     FIG. 2 is a front perspective exploded view of the chuck of FIG. 1; 
     FIG. 3 is a rear perspective exploded view of the chuck of FIG. 1; and 
     FIG. 4 is a sequence of three schematic drawings showing the method of operation of the chuck of FIG. 1. 
    
    
     A chuck generally indicated at 1 comprises stub shaft means in the form of an essentially cylindrical body 2 having an elongate axially inner (with respect to the core of a roll to be engaged by the chuck) portion 3 of smaller diameter than said core internal diameter joined by a frusto-conical portion 4 to a portion 5 of greater diameter than said internal diameter. A boss 6 extends coaxially from the portion 5 for location in the bore 7 of an annular mounting flange 8. Four threaded blind bores 9 extend axially into the portion 5 at circumferentially spaced locations. These bores receive threaded bolts extending through bores 10 in mounting flange 8 to secure the body 2 and flange 8 together. 
     Four circumferentially equally spaced keyways 11 extend axially through the body 2 with their mounting surfaces comprising bases 12 planar and tangential to the axis of the body and inclined to diverge from said axis in the direction from the portion 3 to the portion 5. 
     The mounting flange 8 has three circumferentially spaced bores 13 extending axially therethrough at positions spaced radially outwardly of the body portion 5. These bores 13 are located and dimensioned to receive bolts for connecting the flange to mounting plates on a shaftless mill roll stand. A diametrically spaced pair of pins 14 extend axially forward from the flange 8 to be received in co-operating blind bores 15 in cone end abutment means in the form of an annular actuating member 16 slidably carried by the body 2. The flange 8 also has eight blind bores 17 circumferentially spaced and axially aligned with corresponding blind bores 18 in the annular member 16. Each aligned pair of bores 17 and 18 accommodate the respective ends of a spring means in the form of a compression spring 19 resisting axial movement of the annular member 16 towards the flange 8. 
     The annular member 16 has an internal diameter such that it is an axially sliding fit over the body portion 5. The member 16 has a circumferentially extending groove 20 in its radially inner surface to receive a radially projecting part 21 at the axially outer end of each of four movable jaw means (cylinder-engaging elements) in the form of sliding dogs 22 received in respective keyways 11. 
     Each dog 22 is of substantially triangular cross-section having an inclined planar radially inner surface 23 and a part-cylindrical radially outer surface 24 so that, with the surface 23 abutting the base 12 of the relevant keyway 11, said surface 24 extends axially. The curvature of surface 24 is selected such that the surface is an arc of a cylinder of the nominal internal diameter of the roll core. The axially inner end of each dog 22 has an inclined radially outer surface 25 which is convergent with the axis in the axially inner direction and which also has a part-cylindrical surface of greater curvature than the surface 24. 
     A cone 26 accommodates the axially inner ends of dogs 22 within a convergent frusto-conical recess 27 which extends about the surfaces 25. A central bore 28 extends through the cone 26 to receive a bolt 30 which extends into and is threadably received in a threaded central blind bore 29 in the body portion 3. The cone 26 has an axially extending pin 31 adapted to be received in a blind hole 32 at the axially inner end of the body 2. Similarly, a pin 33 extends axially forwards of said end of the body 2 to be received in a blind hole 34 diametrically opposed to said pin 31. 
     In use, with the chuck 1 secured by flange 8 to a shaftless mill roll stand, the annular member is retained in a rearward position relative to flange 8 by the compression springs 19. The dogs 22 are retained in slide groove means provided by their respective keyways 11 by location of their projections 21 in groove 20 and of their distal ends in recess 27 which provide housing mean therefor. The chuck is moved by the drive mechanism of the mill roll stand axially into the core of a roll 35 of paper or like web material (see FIG. 4a). When the annular member 16 abuts the end of the core further axial movement of that member relative to the core is prevented (see FIG. 4b). Accordingly further axial movement of the body 2 causes relative axial movement between the flange 8 and member 16 against the bias of the springs 19. Such relative movement causes the dogs 22 to ride up the inclined surfaces 12 thereby moving the core-engaging surfaces 24 radially outwardly until they firmly abut the inner surface of the core. In this radially outer configuration of the dogs 22, the core is frictionally engaged with the chuck for rotation therewith (see FIG. 4c). Such engagement will not cause the core to split, allows for variations in internal core diameters from one roll to another of the same nominal internal diameter and secures the core at all speeds and during braking. When it is desired to remove the chuck 1 from the core, the body 2 is moved axially in the direction away from the core thereby allowing the annular member to return under the bias of springs 19 to its rearward position whence the dogs 22 will slide down the inclined surfaces 12 to reduce the extent of radial projection of surfaces 24 and permit complete removal of the chuck from the core. 
     It will be appreciated that the invention is not restricted to the details given above but that numerous modifications and alternations can be made without departing from the scope of the invention as defined in the following claims.