Support spindle for windable material coils

Abstract

A support spindle includes a central shaft defining a rotation axis and forming a connecting portion and a supporting portion extending from the connecting portion along the rotation axis, cam seats formed in the supporting portion, locking bodies arranged radially outside the supporting portion and in contact, by cam-follower members, with the cam seats, a supporting cage connected to the central shaft and which accommodates the locking bodies so the locking bodies can slide radially to the rotation axis with respect to the central shaft and rotate about the rotation axis with respect to the central shaft. A relative rotation between the locking bodies and the central shaft along an angular stroke causes a radial displacement of the locking bodies between a retracted position and an expanded position. The cam-follower members form a first convex cam surface in contact with a second concave cam surface of the corresponding cam seat.

1 . A support spindle ( 1 ) to engage a tubular winding core ( 2 ) for winding and unwinding windable material ( 3 ) to form a coil ( 4 ), comprising:
 A) a central shaft ( 5 ) defining a rotation axis ( 6 ) and forming:
 a connecting portion ( 7 ) on a rear side ( 8 ) of the support spindle ( 1 ), 
 a supporting portion ( 9 ) extending from the connecting portion ( 8 ) along the rotation axis ( 6 ) towards a front side ( 10 ) of the support spindle ( 1 ), 
   a plurality of cam seats ( 11 ) formed in the supporting portion ( 9 ),   B) a plurality of locking bodies ( 12 ) arranged radially outside the supporting portion ( 9 ) and in contact, by means of cam follower members ( 13 ), with the cam seats ( 11 ),   C) a supporting cage ( 14 ) connected to the central shaft ( 5 ) and forming a plurality of guide seats ( 15 ) which accommodate and position the locking bodies ( 12 ) so that the locking bodies ( 12 ) can slide radially to the rotation axis ( 6 ) with respect to the central shaft ( 5 ) and rotate about the rotation axis ( 6 ) with respect to the central shaft ( 5 ),   wherein the cam seats ( 11 ) and cam follower members ( 13 ) are shaped so that a relative rotation between the locking bodies ( 12 ) and the central shaft ( 5 ) about the rotation axis ( 6 ), along an angular stroke ( 16 ), causes a radial displacement of the locking bodies ( 12 ) between a radially inner retracted position, and a radially outer expanded position, for disengaging and engaging the support spindle ( 1 ) with the winding core ( 2 ),   wherein the cam follower members ( 13 ) form a first convex cam surface ( 17 ) in contact with a second concave cam surface ( 18 ) of the corresponding cam seat ( 11 ).   
     
     
         2 . A support spindle ( 1 ) according to  claim 1 , wherein, on a sectional plane orthogonal to the rotation axis ( 6 ), the first convex cam surface ( 17 ) has a circular arc shape and the second concave cam surface ( 18 ) has a symmetrical shape with respect to a symmetry plane ( 19 ) radial to the rotation axis ( 6 ), with an arch-shaped bottom section ( 20 ) and two opposite side sections ( 21 ). 
     
     
         3 . A support spindle ( 1 ) according to  claim 1 , wherein a radial depth ( 23 ) of the cam seat ( 11 ) is greater than the total radial stroke ( 24 ) of the locking bodies ( 12 ) and a circumferential width ( 25 ) of the cam seat ( 11 ) is greater than four times the radial depth ( 23 ) of the cam seat ( 10 ). 
     
     
         4 . A support spindle ( 1 ) according to  claim 1 , wherein:
 the connecting portion ( 7 ) comprises a circular disc-shaped connecting flange extending on a plane orthogonal to the rotation axis ( 6 ) and forming a plurality of fixing holes ( 26 ),   the supporting portion ( 9 ) has an elongated shape with a cylindrical outer surface in which the cam seats ( 11 ) are formed,   the cam seats ( 11 ) are extended parallel to the rotation axis ( 6 ) along the entire supporting portion ( 9 ) and have a constant cross-section shape along the rotation axis ( 6 ).   the supporting portion ( 9 ) comprises three cam seats ( 11 ) evenly distributed at an angular pitch of 120°.   
     
     
         5 . A support spindle ( 1 ) according to  claim 1 , wherein the bottom section ( 20 ) is shaped as an arc of a circle. 
     
     
         6 . (canceled) 
     
     
         7 . A support spindle ( 1 ) according to  claim 1 , wherein the side sections ( 21 ) are joined at opposite ends of the bottom section ( 20 ) with an orientation tangent to the arc of a circle of the bottom section ( 20 ) and wherein a side edge ( 30 ) in an intersection region of the side sections ( 21 ) with an outer circumference of the supporting portion ( 9 ) is beveled. 
     
     
         8 . (canceled) 
     
     
         9 . A support spindle ( 1 ) according to  claim 1 , wherein the locking bodies ( 12 ) form:
 (A) a radially outer, cylinder part-shaped engagement surface ( 36 ) having a length in the direction of the rotation axis ( 6 ) greater than a width thereof in circumferential direction with respect to the rotation axis ( 6 ),   wherein at two opposite longitudinal ends ( 37 ) of the locking body ( 12 ) the engagement surface ( 36 ) is inclined in a radially inward direction,   B) sliding surfaces ( 38 ,  39 ), transverse to the engagement surface ( 36 ), shaped in a complementary manner with corresponding guiding surfaces ( 40 ,  41 ) of the guiding seats ( 15 ) of the supporting cage ( 14 ),   C) a radially inner surface ( 42 ) facing the supporting portion ( 9 ) and accommodating one or more rolling cam-follower members ( 13 ),   D) one or more stop protrusions ( 48 ) which abut against corresponding end of stroke surfaces ( 49 ) of the supporting cage ( 14 ) when the locking body ( 12 ) reaches the expanded position.   
     
     
         10 . A support spindle ( 1 ) according to  claim 9 , wherein the cam follower-members ( 12 ) are elongated cylindrical bodies inserted into the partially cylindrical-shaped cavities ( 43 ) in the direction parallel to the rotation axis ( 6 ). 
     
     
         11 . A support spindle ( 1 ) according to  claim 9 , wherein the radially inner surface ( 42 ) of the locking bodies ( 12 ) forms two side cavities ( 44 ), arranged on two opposite sides with respect to the cam-follower member ( 13 ), wherein said side cavities ( 44 ) are delimited, on one side by the cam-follower member ( 13 ) and on the other side by one of two side guide walls ( 45 ) extended on each longitudinal side of the locking body ( 12 ), protruding towards the inside of the support spindle ( 1 ). 
     
     
         12 . (canceled) 
     
     
         13 . A support spindle ( 1 ) according to  claim 1 , wherein in the retracted position the locking bodies ( 12 ) protrude with respect to an outer surface ( 47 ) of the supporting cage ( 14 ), with an initial radial protrusion ( 46 ) in the range from 5% to 15% of the total radial stroke ( 24 ), or 10% of the total radial stroke ( 24 ), or 0.5 mm. 
     
     
         14 . A support spindle ( 1 ) according to  claim 1 , wherein the supporting cage ( 14 ) comprises a tubular wall ( 51 ), inserted concentrically on the supporting portion ( 9 ) of the central shaft ( 5 ), and having a cylindrical outer surface ( 47 ) and an inner surface ( 52 ) facing the supporting portion ( 9 ),
 wherein the guiding seats ( 15 ) are formed by through openings in the tubular wall ( 51 ), delimited by longitudinal guiding surfaces ( 40 ) and transverse guiding surfaces ( 41 ) for the guided sliding support of the locking bodies ( 12 ),   wherein on the front side ( 10 ) of the support spindle ( 1 ) the supporting cage ( 14 ) is beveled so that the support spindle ( 1 ) can be more easily inserted into the winding core ( 2 ),   wherein the supporting cage ( 14 ) is locked axially on the central shaft ( 5 ) by means of a closing plug ( 55 ) screwed to a front surface of the central shaft ( 5 ),   wherein the closing cap ( 55 ) is also beveled continuing the beveling of the supporting cage ( 14 ).   
     
     
         15 . A support spindle ( 1 ) according to  claim 1 , comprising two of said concentric supporting portions ( 9 ,  9 ′) and having different diameters, as well as a plurality of said concentric supporting cages ( 14 ,  14 ′) having different diameters and positioned axially next to each other, with the smaller diameter supporting cage ( 14 ,  14 ′) positioned more on the front side ( 10 ) of the support spindle ( 1 ). 
     
     
         16 . A support spindle ( 1 ) according to  claim 1 , comprising a positioning and ejection flange ( 57 ) axially sliding with respect to the central shaft ( 5 ) and guided by a plurality of guiding grooves ( 58 ) parallel to the rotation axis ( 6 ), formed in an outer surface of the supporting cage ( 14 ). 
     
     
         17 . A support spindle ( 1 ) according to  claim 1 , wherein the supporting cage ( 14 ,  14 ′) forms one or more radial friction protrusions ( 60 ) adapted to engage the core ( 2 ) constantly in direct contact and with a friction such as to ensure minimum torque transmission from the core ( 2 ) to the supporting cage ( 14 ,  14 ′) even when the locking bodies ( 12 ) are not yet or no longer activated. 
     
     
         18 . A support spindle ( 1 ) according to  claim 1 , wherein to each of said locking bodies ( 12 ) is associated exactly and only one of said cam follower members ( 13 ). 
     
     
         19 . A support spindle ( 1 ) according to  claim 2 , wherein to each of said locking bodies ( 12 ) is associated exactly and only one of said cam follower members ( 13 ). 
     
     
         20 . A support spindle ( 1 ) according to  claim 1 , wherein each said locking body ( 12 ) forms a radially internal surface ( 42 ) facing the support portion ( 9 ) and forming a partially cylindrical cavity ( 43 ) extending in a direction parallel to the rotation axis ( 6 ),
 in which said cavity ( 43 ) rotatably accommodates one of said cam follower members ( 13 ) having an elongated cylindrical shape and being extended in a direction parallel to the axis of rotation ( 6 ),   wherein between respectively one locking body ( 12 ) and the support portion ( 9 ) there is interposed:
 only one of said cam follower members ( 13 ) having elongated cylindrical shape, or 
 a group of said cam follower members ( 13 ) of elongated cylindrical shape, in which all said cam follower members ( 13 ) of the group are positioned and oriented concentric with each other and parallel to the rotation axis ( 6 ). 
   
     
     
         21 . A support spindle ( 1 ) according to  claim 2 , wherein each said locking body ( 12 ) forms a radially internal surface ( 42 ) facing the support portion ( 9 ) and forming a partially cylindrical cavity ( 43 ) extending in a direction parallel to the rotation axis ( 6 ),
 in which said cavity ( 43 ) rotatably accommodates one of said cam follower members ( 13 ) having an elongated cylindrical shape and being extended in a direction parallel to the axis of rotation ( 6 ),   wherein between respectively one locking body ( 12 ) and the support portion ( 9 ) there is interposed:
 only one of said cam follower members ( 13 ) having elongated cylindrical shape, or 
 a group of said cam follower members ( 13 ) of elongated cylindrical shape, in which all said cam follower members ( 13 ) of the group are positioned and oriented concentric with each other and parallel to the rotation axis ( 6 ).