Tyre Building Drum

Abstract

A tyre building drum is disclosed having first and second sets of deck segments, the segments ( 11, 12 ) of the sets alternating in a circumferential direction in the expanded deck, such that a pair of segments of said first set lie immediately circumferentially adjacent, and on opposite circumferential sides respectively of each segment of the second set and vice-versa, the axially extending edges ( 12 a ) of the segments ( 12 ) of said second set each including a circumferentially extending protrusion which underlies the deck surface of the adjacent segment of the first set, whereby the expanded segments interlock to resist radial loading on the deck in a direction to collapse the deck. The drum construction provides a high degree of lateral and radial deck stability and accuracy.

1 - 7 . (canceled) 
   
   
       8 . A tyre building drum comprising a rotatable hub assembly, a plurality of deck segments supported from the hub assembly through the intermediary of respective linkage arrangements for expanding and contracting movement between a collapsed position in which the drum has a relatively small overall diameter and an expanded position in which the deck segments define a cylindrical tyre building deck of the drum of significantly larger overall diameter, said deck segments comprising first and second sets of segments, the segments of the sets alternating in a circumferential direction in the expanded deck, such that a pair of segments of said first set lie immediately circumferentially adjacent, and on opposite circumferential sides respectively of each segment of the second set and vice-versa, the axially extending edges of the segments of said second set each including a circumferentially extending protrusion which underlies the deck surface of the adjacent segment of the first set, whereby the expanded segments interlock to resist radial loading on the deck in a direction to collapse the deck. 
   
   
       9 . A tyre building drum according to  claim 8 , wherein the axially extending edges of the segments also include surfaces which abut in the fully expanded position of the deck segments to interlock the segments against relative axial movement. 
   
   
       10 . A tyre building drum according to  claim 8 , wherein a drive arrangement including said linkage arrangements, for driving said segments between their collapsed and expanded positions is arranged to ensure that the segments of the first set reach their fully expanded position in advance of the segments of the second set, whereby the segments of the second set enter between the fully expanded segments of the first set so that the segments interlock in the fully expanded position of all of the segments. 
   
   
       11 . A tyre building drum according to  claim 10 , wherein said drive arrangement ensures that the segments of the second set commence their collapsing movement from the fully expanded position prior to the commencement of the collapsing movement of the segments of the first set. 
   
   
       12 . A tyre building drum according to  claim 10 , wherein the drive arrangement includes a common drive member for driving all of the linkage arrangements of the segments of the first and second sets, and a lost motion arrangement is incorporated between the drive member and the linkage arrangements of the segments of the first set whereby the drive member can continue to move, driving the linkage arrangements of the segments of the second set, after the segments of the first set have reached their fully expanded position. 
   
   
       13 . A tyre building drum according to  claim 8 , wherein, in the fully collapsed position of said segments, the axially extending edges of the segments of the first set are closely proximate, one another, and the segments of the second set lie radially inwardly and beneath the segments of the first set. 
   
   
       14 . A tyre building tyre drum comprising a rotatable hub assembly, a plurality of deck segments supported from the hub assembly through the intermediary of respective linkage arrangements for expanding and contracting movement between a collapsed position in which the drum has a relatively small overall diameter and an expanded position in which the deck segments define a cylindrical tyre building deck of the drum of significantly larger overall diameter, said deck segments comprising first and second sets of segments, the segments of the sets alternating in a circumferential direction in the expanded deck, such that a pair of segments of said first set lie immediately circumferentially adjacent, and on opposite circumferential sides respectively of each segment of the second set and vice-versa, the drum incorporating a drive arrangement including said linkage arrangements, for driving said segments between their collapsed and expanded positions said drive arrangement ensuring that the segments of the first set reach their fully expanded position in advance of the segments of the second set, whereby during drum expansion said segments of the second set enter between the fully expanded segments of the first set. 
   
   
       15 . A tyre building drum according to  claim 14 , wherein said drive arrangement ensures that the segments of the second set commence their collapsing movement from the fully expanded position prior to the commencement of the collapsing movement of the segments of the first set. 
   
   
       16 . A tyre building drum according to  claim 14 , wherein the drive arrangement includes a common drive member for driving all of the linkage arrangements of the segments of the first and second sets, and a lost motion arrangement is incorporated between the drive member and the linkage arrangements of the segments of the first set whereby the drive member can continue to move, driving the linkage arrangements of the segments of the second set, after the segments of the first set have reached their fully expanded position. 
   
   
       17 . A tyre building drum according to  claim 14 , wherein, in the fully collapsed position of said segments, the axially extending edges of the segments of the first set are closely proximate one another, and the segments of the second set lie radially inwardly and beneath the segments of the first set.