Abstract:
A rotatable drum useful in the manufacture of vehicle tires. A plurality of segments collectively define the outer circumferential surface of the drum. These segments are divided into two sets, one set being disposed on each of the opposite sides of a transverse center plane of the drum, the center plane being oriented normal to the rotational axis of the drum. The two sets of segments are mounted for selective positioning thereof axially of the drum from a location external of the drum to adjust the overall working width of the drum. Further, the segments are selectively positionable between expanded positions radially of the rotational axis of the drum to provide a relatively continuous circumferential outer surface of the drum for the layup of a tire carcass thereon, and collapsed positions radially of the drum to permit the removal of a formed toroidal carcass from the drum. Movement of the plurality of segments of each of the two sets of segments radially of the rotational axis of the drum is effected by “slaving” the two sets of segments off a central mechanism which controls the radial positions of all the segments simultaneously and equidistantly from the rotational axis of the drum, while further providing for axial movement of the two sets of segments relative to one another while the segments are positioned at any given radial location of the segments.

Description:
FIELD OF INVENTION 
     This invention relates to tire building drums and particularly to a drum which is adjustable in width for use in the manufacture of tires of different widths employing the same drum. 
     BACKGROUND OF THE INVENTION 
     In the manufacture of vehicle tires, it is common practice to build up the tire carcass from individual components which are overlaid onto the outer circumference of a rotatable drum. Removal of the formed tire carcass from the drum requires collapse of the diameter of the drum to an extent sufficient to allow the toroidal carcass to be removed from the drum. U.S. Pat. No. 4,636,277 (the “277 patent”) discloses a tire building drum of this type. This prior art drum is also representative of prior art drums wherein any change in the width of the drum requires physical exchange of spaces between the outer shell segments which define the outer circumference of the drum to that size required for the manufacture of a given tire width size. This process is well known in the art to be cumbersome, time-consuming and expensive, and requires the keeping of an inventory of spacers. 
     Functionally, the drum of the “277 patent” requires special structure, and orientation of such structure, to successfully and repeated effect proper mating of the axially aligned side edges of adjacent ones of the segments to define a suitable working outer circumferential surface of the drum. Specifically, with reference to FIGS. 1 and 2 of the “277 patent”, it will be noted that the inboard ends of alternating ones of the radial support structures  14  are mounted on the rotating hub  11  at respective locations which are offset from a radius drawn from the central axis of the drum through the center of the outboard end of a given radial support  14 . These offset alignments of the radial support members permits the smaller segments to move radially inwardly of the drum in advance of the radially inward movement of the larger segments as is required to permit collapse of the segments toward the rotational axis of the drum. This mechanism further causes the larger segments to move radially outward of the drum in advance of the movement of the smaller segments radially outwardly of the drum when expanding the diameter of the drum. However, this mechanism causes the larger segments to move radially beyond their desired most radially outward positions and then to move radially inwardly to mate with the advancing smaller segments. Control over the precise mating of the larger and smaller segments at their desired outer limit of travel has proven to be difficult to control. As a consequence addition of an adjustable stop mechanism has been employed to improve the desired stop positions of the mating side edges of the larger and smaller segments. This stop mechanism, however, must be fixedly mounted, preferably welded, in place adjacent each of the opposite side edges of the smaller segments before assembly of the drum, and its stop limit adjusted after assembly of the drum. This mechanism provides only for a “single point” adjustment of the position of the side edge of a larger segment relative to a cantilevered extension of the smaller segment. Accordingly, this mechanism represents an undesirable added cost in time and constitutes a point of potential need for ongoing adjustment over the useful life of a drum. 
     It is therefore an object of the present invention to provide a tire building drum which is expansible in diameter and selectively changeable in both its diameter and its axial width without exchange of the outer segments that collectively define the outer circumferential surface of the drum or the use of spacers. 
     It is another object to provide a drum of the type described in which the adjustment of the width of the drum may be effected from a location external of the drum. 
     As is another object to provide a radially expansible tire building drum having improved control over the mating of its circumference-defining segments 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a drum embodying various of the features of the present invention; 
     FIG. 2 is an planar end view of the the drum depicted in FIG. 1; 
     FIG. 3 is a sectional view taken generally along the line  3 — 3  of the drum depicted in FIG. 2; 
     FIG. 4 is a sectional view taken generally along line  4 — 4  of the drum depicted in FIG. 2; 
     FIG. 5 is a sectional view taken generally along line  5 — 5  of FIG. 4; 
     FIG. 6 is an exploded view of various of the internal working elements of the drum depicted in FIG. 1; 
     FIG. 7 is a perspective view of a hub element of the drum depicted in FIG. 1; 
     FIG. 8 is a sectional view of the hub element of FIG.  7  and taken generally along the line  8 — 8  of FIG. 7; 
     FIG. 9 is a perspective view of the hub element of FIG.  7  and transition elements associated therewith; 
     FIG. 10 is a perspective view of various assembled internal working elements of the drum depicted in FIG. 1; 
     FIG. 11 is a perspective view of a small segment of the drum depicted in FIG. 1; 
     FIG. 12 is a further perspective view of the small segment depicted in FIG. 11; 
     FIG. 13 is a side elevation view of the small segment depicted in FIG. 11; 
     FIG. 14 is a perspective view of a large segment of the drum depicted in FIG. 1; 
     FIG. 15 is a side elevation view of the large segment depicted in FIG. 14; 
     FIG. 16 is a sectional view of the large segment depicted in FIG.  14  and taken generally along the line  16 — 16  of FIG. 14; 
     FIGS. 17A,  17 B and  17 C are sectional views taken generally along line  17 A— 17 A of FIG.  2  and at various depths to depict the mating relationship of the side edges of small and large segments of the drum depicted in FIGS. 1 and 2; 
     FIG. 18A is a plan view of an end shell comprising individual end segments defining an outboard edge of each set of segments; 
     FIG. 18B is a sectional view of the end shell and taken generally along line  18 B— 18 B of FIG. 18A; 
     FIG. 18C is a sectional view of an individual end segment taken generally along line  18 C— 18 C of FIG. 18B; 
     FIG. 19 is a perspective view of a typical gap shield employed in the drum depicted in FIG. 1; 
     FIG. 20 is a sectional view of the gap shield depicted in FIG.  19  and taken generally along the line  20 — 20  of FIG. 19; 
     FIG. 21 is a further sectional view of the gap shield of FIG.  19  and taken generally along the line  21 — 21  of FIG. 19; 
     FIG. 22 is a top plan view of the gap shield depicted in FIG. 19; 
     FIG. 23 is a perspective view of a small segment connector bracket employed to mount a gap shield and alignment rods to which segments are mounted; 
     FIG. 24 is an end view of the bracket depicted in FIG. 23; 
     FIG. 25 is a sectional view taken generally centrally of and parallel to the length of the bracket depicted in FIG. 23; 
     FIG. 26 is a perspective view of a large segment connector bracket employed to mount a gap shield and an alignment rod to which large segments are mounted; 
     FIG. 27 is a sectional view taken generally centrally of and parallel to the length of the bracket depicted in FIG. 26; 
     FIG. 28 is an end view of the bracket depicted in FIG. 26; 
     FIG. 29 is a perspective view of a collar assembly employed in the mounting of segments to the main shaft of the drum depicted in FIG. 1; 
     FIG. 30 is a perspective view of a mounting block employed for mounting lead screws in the drum of the present invention: 
     FIG. 31 is a side elevation view of a lead screw as employed in the drum of the present invention; 
     FIG. 32 is a perspective view of the main shaft of the drum depicted in FIG. 1; 
     FIG. 33 is a perspective view of a housing employed to mount various of the elements employed in effecting and/or recording the axial positioning of the opposite sets of segments of the drum depicted in FIG. 1; 
     FIG. 34 is a further perspective view of the housing of FIG.  32  and including additional elements of the drum of the present invention; 
     FIG. 35 is an exploded view depicting in the placement of various of the drum elements within the housing of FIG. 33; 
     FIG. 36 is a further exploded view depicting the placement of additional drum elements within or associated with the housing of FIG. 33; and, 
     FIG. 37 is an enlarged view of a portion of the left-hand end of the drum depicted in FIG.  3 . 
    
    
     SUMMARY OF INVENTION 
     In accordance with one aspect of the present invention there is provided a rotatable drum useful in the manufacture of vehicle tires. The drum includes a plurality of segments which collectively define the outer circumferential surface of the drum. These segments are divided into two sets, one set being disposed on each of the opposite sides of a transverse centerplane of the drum, the centerplane being oriented normal to the rotational axis of the drum. The two sets of segments are mounted for selective positioning thereof axially of the drum from a location external of the drum to adjust the overall working width of the drum. Further, the segments are selectively positionable between expanded positions radially of the rotational axis of the drum to provide a relatively continuous circumferential outer surface of the drum for the layup of a tire carcass thereon, and collapsed positions radially of the drum to permit the removal of a formed toroidal carcass from the drum. Movement of the plurality of segments of each of the two sets of segments radially of the rotational axis of the drum is effected by “slaving” the two sets of segments off a central mechanism which controls the radial positions of all the segments simultaneously and equidistant from the rotational axis of the drum, while further providing for axial movement of the two sets of segments relative to one another. This central mechanism further provides for mounting and radial movement of a plurality of gap shields which are disposed about the central portion of the outer circumferential surface of the drum. 
     In the present drum, the axial and radial movements of the divided sets of segments are accomplished by unique mechanisms which provide for both selective and coordinated movements of the segments from locations external of the drum. These mechanisms include multiple lead screws which are disposed externally of the central main shaft of the drum and which are actuated simultaneously from a single location external of the drum to effect adjustment of the width of the drum, with disengagement of the lead screws from the external source of their adjustment once the width of the drum is selectively established, thereby ensuring “locking” of the drum width against unintended change thereof. 
     In accordance with another aspect of the present drum, there is provided means for mutual adjustment of the most radially outward “working” positions of the circumference defining segments of the drum. 
     DETAILED DESCRIPTION OF INVENTION 
     As depicted in FIGS. 1-5, a drum  10  in accordance with the present invention includes a main shaft  12  which extends through the width of the drum and defines the rotational axis  14  of the drum. The outer circumferential surface  16  of the drum is defined by first and second sets of segments, indicated generally by the numerals  18  and  20 . In the depicted drum, each set of segments includes four large segments  24 ,  26 ,  28 , and  30  (larger in width) and four small segments  32 ,  34 ,  36  and  38 . The corresponding large and small segments of the second set of segments are identified by primed numerals. Within each set, the larger and smaller segments alternate in their position about the circumference of the drum. The first set  18  of the large and small segments is disposed outboard of the drum and the second set  20  is disposed inboard of the drum. These sets of segments are mounted for simultaneous axial movement toward and away from one another. The circumferential space between the sets of segments at the transverse center plane  19  of the drum is closed by conventional associated small and large gap shields  22  and  23 , respectively (typical) (see also FIGS.  11 , 14  and  18 ). 
     Referring specifically to FIGS. 11-17, the side edges  40 , 42  and  44 , 46  of each segment are chamfered suitably to permit proper engagement of the respective side edges of alternating segments with their neighbor segments to define a substantially continuous outer circumferential surface  16  of the drum. 
     With reference to FIGS.  1  and  18 A,- 18 C, in the depicted embodiment of the present drum, each of the opposite ends of the drum is fitted with a segmented ring  570  which defines the outermost edges of the outer circumference of the drum. Specifically, the segmented ring of the depicted drum includes four segments  24 ′,  26 ′,  28 ′ and  30 ′ which correspond to the four large segments  24 ,  26 ,  28  and  30  of the drum, and four segments  32 ′, 34 ′,  36 ′ and  38 ′ which correspond to the four small segments  32 ,  34 ,  36 , and  38  of the drum, each segment effectively serving as an extension of its respective large or small segment. Each extension segment is mounted to the outboard end of its associated large or small segment, as by screws  571  (typical), for positioning with such associated large or small segment. 
     Each end segment includes a chamfered outermost edge  574 . This feature provides for more uniform and less stressful relative movement between the outermost edges of the drum and the tire fabric carcass which has been overlaid on the drum, as the carcass is expanded in the course of forming of the sidewalls of the carcass. Moreover, the cross-sectional curvature of the chamfered outermost edge of the end segments may be chosen to accommodate different desired tire geometries. 
     Referring to the several Figures and specifically to FIGS.  3 , 4  and  6 - 8 , within the interior of the drum, the main shaft  12  is fitted with an encircling spool-shaped hub  52  which includes a hollow cylindrical central body portion  54  and opposite end radial flanges  56  and  58 . This hub is rotatable about the main shaft but is restrained against axial movement relative to the shaft as by first and second retainer subassemblies  60 , 62 . Each depicted subassembly includes a ring gasket  64 , a collar  66  and a split ring  68  which engages a circumferential slot  70  in the main shaft. As depicted in FIG. 6, the main shaft  12  is provided with a through slot  72  at a location generally centrally of its length and which is aligned with the hub  52 . The depicted hub is provided with a pair of helical slots  74 , 76  through the wall thickness of its central body portion  54 . First and second roller cams  80  and  82  mounted on opposite ends of a shaft  84  are slidably mounted within the through slot  72  in the main shaft and project from the main shaft to reside within respective ones of the helical slots  74 , 76  provided in the wall of the hub  52 . Thus it will be recognized that axial movement of the roller cams  80 , 82  will effect rotational movement of the hub  52 , either clockwise or counterclockwise rotation, depending upon the direction of axial movement of the roller cams within the main shaft. 
     Control of the axial movement of the roller cams  80 , 82  is provided for by means of a drive rod  90  which is mounted within the hollow central cavity  92  of the main shaft  12  for axial sliding movement relative to the main shaft (see FIGS.  3 , 4 , and  6 ). Adjacent the inboard end  94  of the rod  90  there is provided a through bore  96  within which there is received the shaft  84  which mounts the roller cams  80 , 82 . The position of the outboard end  98  of the rod is stabilized within the main shaft. To this end, the interior wall  102  of the main shaft is threaded adjacent the outboard end  103  thereof to threadably receive an outside threaded spanner nut  104  and a lock nut  106  to rotatably position the outboard end  98  of the rod centrally within the hollow interior cavity of the main shaft. The outboard end of the rod is bored and tapped to be engaged with an actuating mechanism associated with the tire making machine proper (not shown), as is known in the art. This known actuating mechanism functions to selectively move the drive rod  90  axially within the main shaft to thereby effect resultant rotational movement of the hub  52 , hence effect radial adjustment of the segments and selection of the diameter (circumference) of the drum. 
     In accordance with one aspect of the present invention, the drive rod  90  is provided with a radial shoulder  108  at a location approximately one-third the length of the rod as measured from the outboard end thereof. Adjacent this shoulder there is provided a shock-absorbing ring  110  which encircles the drive rod and abuts the shoulder  108 . This ring may be of a urethane or like material having a Shore durometer of about 80. Upon withdrawal of the drive rod axially toward the right as viewed in FIGS. 3 and 4, the spanner nut  104  acts as a stop to limit such axial movement of the drive rod when the shock-absorbing ring  110  engages the spanner nut. The present shock-absorbing ring provides both noise reduction and reduction of mechanical failure of the drive rod in the course of its functioning to radially expand and collapse the diameter of the segments of the drum. 
     Within the interior of the drum, the hub  52  is fitted with a plurality of transition brackets  112 , 114  for mounting the segments and gap shields to the hub (see FIGS.  6 , 9  and  10 ). Each transition bracket, bracket  112 , for example, is pivotally mounted between the opposite radial flanges  56 , 58  of the hub  52  as by a respective pivot pin  116 . It is to be noted that the transition brackets comprise first and second sets, each transition bracket of a set having the same geometric configuration. Specifically, the transition brackets  112  of the first set  118  are substantially flat and planar intermediate their respective opposite ends and the transition brackets of the second set  120  are planar but include a bend disposed intermediate their respective opposite ends. The transition brackets of the first set  118  serve to mount the small segments to the hub, while the brackets of the second set  120  serve to mount the large segments to the drum. The bend in transition brackets  114  provide for nesting of the several transition brackets when the segments of the drum are in their collapsed attitude. 
     As depicted in FIG. 9, the outboard end  122  of each transition bracket  112  of set  118  is provided with first and second lugs  124 , 126  (typical) which project radially outwardly from the end of the transition bracket and are spaced apart from one another to define an open space  128  therebetween. Each lug is provided with a respective through bore  130 , 132  through its thickness, with these through bores being in axial register with one another. 
     On the outboard end  122  of each of the several transition brackets  112  of the first set  118  there is pivotally mounted a first connector bracket  123  (see FIGS.  5  and  23 - 25 ) which includes an elongated generally arcuate body portion  136 , opposite end portions  138 , 140  and first and second lugs  142 , 144  which project from the inner surface  146  of the body portion. The transition brackets  112  of the first set  118  thereof and their accompanying connector brackets  123  serve to mount the small segments  32 ,  32 ′ (typical) and the gap shields associated with the small segments to the hub. To this end, in the depicted embodiment, a respective gap shield  22  is secured to the outboard surface  125  of each first connector bracket as by screws  147  (typical) which are received in threaded bores  150 , 152  in the body portion of each connector bracket. 
     Each of the lugs  142 , 144  is provided with a respective through bore  154 , 156 . For purposes which will appear hereinafter, the respective through bores of the first and second lugs are aligned axially of the drum, ie., parallel to the rotational axis  14  of the drum. 
     One of the lugs, lug  142  for example, of each of the first connector brackets  123  projects radially inwardly from the body portion of the connector bracket and is dimensioned to be received within the open space  128  defined between the first and second lugs  124  and  126  on the outboard end of a respective transition bracket  112  and with its through bore  154  in register with the registered through bores  124 , 126  of the first and second lugs of the transition bracket. Pin means  160  is provided within these registered through bores to pivotally mount the connector bracket to its respective transition bracket. For purposes which will appear hereinafter, the pin  160  extends axially from the connector bracket  112  to provide opposite cantilevered ends  162 , 164 . Each of the ends  162 , 164  of the pin  160  extend to approximately its respective end of the drum as best seen in FIG.  3 . 
     On the outboard end  170  of each of the transition brackets  114  of the second set  120  of transition brackets  114  there is pivotally mounted a second connector bracket  172 . The transition brackets of this second set  120  and their accompanying connector brackets  172  serve to mount the large segments and the gap shields  23  associated with the large segments, to the hub. To this end, in the depicted embodiment, a respective gap shield  23  is secured to the outboard surface  175  of each second connector bracket as by screws  149  (typical). 
     Each of the transition brackets  114  of the second set of transition brackets  120  includes an elongated generally arcuate body portion  190  having opposite ends  192  and  194 . A mounting lug  196  is provided on the radially inward surface  198  of each of the second transition brackets  114  and projects therefrom and is configured to be received within the open space  200  defined between the first and second outboard end lugs  208 , 210  of its respective transition bracket  114 . This mounting lug  196  is provided with a through bore  202  extending through its thickness, this through bore being in register with the through bores  204 , 206  of the lugs  208 , 210  of its respective transition bracket  114 , for example. These registered bores are pivotally connected as by a first guide pin  160 ′ to pivotally mount each of the transition brackets of the second set of transition brackets with their respective connector brackets and large segments and associated gap shields. As depicted, this guide pin  160 ′ is of a length such that its opposite ends  211 , 213  extend axially from opposite sides of, and beyond, the transverse center plane  19  of the drum to terminate at respective locations adjacent the opposite ends of the drum as best seen in FIG.  4 . 
     In accordance with one aspect of the present invention, a second guide pin is received within the through bore  156  of the first lug  144  of the connector bracket  123 . This pin also is of a length such that its opposite ends extend axially from opposite sides of, and beyond, the transverse center plane  19  of the drum to terminate at respective locations adjacent the opposite ends of the drum. Notably, the first and further pins  160 , 212  are aligned parallel to one another, but spaced apart from one another and serve to maintain the alignment of the left-hand and right-hand ones of the small segments of each of the sets  18  and  20  of segments. In the depicted embodiment only the small segments are interconnected by two guide pins inasmuch as the larger segments are not prone to deleterious misalignment between the left-hand and right-hand sets of large segments. 
     Referring specifically to FIGS. 1-4 and  6 , in the depicted drum, the large and small segments of each of the first and second sets of segments are mounted for radial movement toward and away from the main shaft  12 . Each set of segments is provided with a respective first and second collars  220  and  222 , each of which encircles and is non-axially and non-rotatably mounted on the main shaft. The depicted first collar  220  is provided with eight sides (as viewed in FIG.  29 ). The second collar  222  is a mirror image of the first collar. Each side surface  224 , for example, of the collar is bored  226  and receives therein a rod  228 , 234  which projects radially outwardly from its respective side of the collar. As depicted in FIG. 6, the outboard end  230 , 231  of each of the rods  228 , 234  slidably receives thereover a hollow tubular projection  235 , 237  which is mounted on the inner surface  234 , 236  of each of the small and large segments  32 , 24 , respectively, (typical) of a given set of segments and which projects radially inwardly of the drum. By this means, each segment is secured in its desired position relative to the main shaft and relative to its neighbor segments, while providing for radial movement of the plurality of segments during collapse or expansion of the outer circumference of the drum. 
     Further, on the inner surface  236  of each of the large segments  24  (typical) of each of the first and second sets of segments, there is provided a lug  240  which projects from the segment radially inwardly of the drum when the segment is mounted on the drum. The outboard end  242  of each such lug on a given large segment is provided with a through bore  244  whose axis is in register with the axis of the through bore  202  in the lug  196  on that connector bracket  172  which is associated with the given large segment. Thus, the outboard end  213  of the alignment rod  160  is slidably received within the through bore  244  of the lug  240 . The width dimension of the lug  240 , hence the length of its through bore, and the sliding fit of the alignment rod  160  with this through bore are chosen to ensure minimal torqueing or warping of the given large segment in any direction relative to the axis of the through bore  244 . 
     Whereas the mounting of only one large segment of the first set of segments has been described, it will be recognized that each large segment of each of the first and second sets of segments is substantially likewise mounted relative to the main shaft. 
     As described, each large segment of the drum is slidably mounted for movement axially along its respective end of its respective alignment rod  160 . In the depicted embodiment, only one alignment rod  160 ′ is associated with each large segment  24  of a set of segments. The opposite end  242  of this same rod is associated with the corresponding large segment of the second set of segments. 
     In the depicted drum, each of the small segments of each of the first and second sets of segments includes an arcuate body portion  250  and a first mounting lug  259  projecting radially inwardly of the rum. This lug  259  is provided with a through bore  261  which is dimensioned to snugly slidably received therein one outboard end  162  (for example) of the alignment rod  160 . As noted hereinabove, a hollow tubular projection  235  projects radially inwardly from the inner surface  233  of the small segment to slidably receive therein the outboard end of one of the rods  228 , for example, which extends radially outwardly from the collar  220 . Thus, the mounting of the small segments of each set is substantially like the mounting of the large segments of each set of segments. As also noted hereinabove, for purposes of enhanced rigidity of alignment of the small segments relative to the rotational axis of the drum and relative to each other and their neighboring segments, each small segment is provided with a further lug  260  on the inner circumference of the segment and which is spaced circumferentially apart from the first lug  259  on the segment. This further lug is substantially identical to the first lug and is provided with a like through bore  262  whose axis is aligned parallel to the main shaft and parallel to the axis of the through bore  261  of the first lug  259 . This through bore  262  of the further lug  260  of a given small segment slidably receives therein one end of the pin  212  which is mounted in the lug  144  on that connector bracket  123  which is associated with the transition bracket  112  for the given small segment. The corresponding small segment  32 , for example, of the second set  20  of segments is likewise provided with a further lug  260 ′ which includes a through bore in its radially inward end and which slidably receives therein the opposite end  164  of the rod  212 . By this means, each small segment of each set of segments is stabilized with respect to its associated transition bracket, hence with respect to the alignment of the small segments with the main shaft of the drum. 
     Inasmuch as the alignment of the large and small segments is maintained mechanically, the alignment is retained at all radial positions of each of the large and small segments irrespective of the radial positions of the segments at any given time and within their respective limits of travel. Further, through the means of the plurality of alignment rods whose opposite ends extend axially from their anchored central portion, in opposite directions from the transverse center plane of the drum to slidably receive respective small segments thereon, each of the small segments is retained in precise alignment with the main shaft (parallelism with the main shaft over their limits of axial travel; circumferential relationship to the main shaft, hence precise positioning of all of the segments as they are brought into mating relationship for defining the outer circumferential surface of the drum). Further the alignment rods  160  provide support and guidance as the first and second sets of segments are adjusted axially of the transverse centerplane of the drum to selectively adjust the width of the drum. In this manner, the two sets of segments are “slaved” off the central control mechanism. That is, the segments of each set of segments are indirectly connected (through the rods  160 ) to the central control mechanism. 
     With specific reference to FIGS. 14-16, it will be noted that each of the large segments of each set of segments, segment  24 , for example, includes opposite side edges  270  and  272  which are oriented parallel to the rotational axis  14  of the drum when the segment is mounted on the drum. In like manner, each of the small segments, segment  32 , for example, includes opposite side edges  274  and  276  which are also oriented parallel to the rotational axis of the drum. When the drum is expanded to its designed maximum diameter, one of the side edges  270 , 272  of each large segment  24  matingly engages a side edge  274 , 276  of each of its respective neighboring small segments. (See FIGS.  14 - 17 ). As noted hereinabove, each side edge of each of both the large and small segments is chamfered to permit such mating engagement of these side edges. Specifically, each of the side edges  270  and  272  of each large segment is both chamfered and provided with a transverse groove  278 , 280  to thereby define an arcuate ledge  282 , 284  which extends substantially between the opposite ends  286 , 288  of the segment. Approximately midway between the opposite ends  286 , 288  of each of the grooves  278 , 280  there are provided outwardly opening slots  290 , 292 , respectively, disposed in each of the side walls  294 , 296  of the grooves  278 , 280 . 
     Each of the side edges  274  and  276  of each of the small segments of each set of segments, segment  32 , for example, are similarly chamfered as indicated at  300 , 302  (see FIGS. 11-13 and  17 A,  17 B and  17 C. Further, each of the side edges  274 , 276  of each small segment is provided with a transverse groove  304 , 306  to define arcuate ledges  308 , 310  which extend between the opposite ends  312 , 314  of the small segments. Approximately midway between the opposite ends of each of the arcuate ledges  308 , 310  of each of the small segments there is provided an alignment dowel  316 , 318  which is designed to engage respective ones of the slots  290 , 292  in the mating side edges of neighboring large segments when the side edges of the large and small segment come together in mating relationship as the diameter of the drum is established. (See also FIGS. 17A and 17B) Further, each of the small segments is provided with first and second internally threaded bores  320  and  322 , respectively, which are disposed generally adjacent respective ones of the opposite ends of each of the small segments and which extend from the surface  324  of the outer wall  326  of the groove  304 , for example, fully through the thickness of the segment in a direction substantially normal to the planar wall  326  of the groove. Third and fourth internally threaded bores  328  and  330  are provided on each of the side edges of each small segment at respective locations adjacent respective ones of the ends of the chamfered surface  332  of each side edge of each small segment. Each of these third and fourth bores extends fully through the thickness of the segment from the surface  332  of the tongue  308  of the segment. Each of the first and second and fourth and fifth bores is designed to threadaby receive therein a flat point set screw  334 , 336  and  338 , 340  respectively, for example. 
     With reference to FIGS.  2 , 17 A and  17 B, when the side edge  270  of a large segment  24  matingly engages a respective side edge  276  of a neighboring small segment  32 , as when the diameter of the drum is maximized to develop its designed maximum outer circumferential surface, the ledge  310  of the small segment is received with the groove  280  of the large segment and the dowel  318  projecting from the side wall of the groove  306  of the small segment is received within the slot  292  in the wall  296  of the groove  280  of the large segment, thereby establishing side-to-side alignment of these adjacent segments. As depicted in FIGS. 17A-17C, when the large and small segments are in mating engagement, the flat end of each of the set screws  334 , 334 ′ of each small segment can engage the wall  295  of the mating large segment and the flat end of each of the third and fourth set screws  336 , 336 ′, can engage the wall  297  of the groove  280 . Thus, by adjusting the depth of penetration of each of the first, second, third and fourth set screws  334 , 336 , 338 ,and  340  within their respective internally threaded bores, the angularity of alignment of the mating segments and the relative radial positioning of the large segment with respect to its respective adjacent small segments may be adjusted. These degrees of alignment serve to more perfectly align the several segments and more perfectly define a true circumferential outer surface for the drum. In the present drum, these first, second, third and fourth set screws are readily accessible for a respective end of the drum for adjustment as needed over the operational life of the drum. 
     In the depicted embodiment of the present drum, each of the collars  220  and  222  includes a plurality, three in the depicted embodiment, of arcuate sections  400 , 402  and  404  which are disposed with their ends adjacent to one another to define a first discontinuous hollow cylinder indicated generally by the numeral  406  mounted on the outboard face  408  of the collar and encircling the main shaft  12 . A locking ring  411  and screws  413  serve to secure the arcuate sections  400 , 402 , 404  to the face  408  of the collar  220 . Between the adjacent ends of the arcuate sections, first, second and third mounting blocks  410 , 412  and  414 , respectively are anchored to the outboard face  408  of the collar as by bolts  416 , 418  and  420 , respectively, which extend through one end of their respective blocks and threadably engage the collar  220 . The opposite end of each block projects radially inwardly of the discontinuous cylinder  406  and is provided with an internally threaded through bore  424  whose axis  426  is oriented parallel to the main shaft  12 . In the depicted embodiment there are provided three such blocks which are spaced apart from one another in the discontinuities of the discontinuous hollow cylinder  406 . Each of the internally threaded through bores of a block is designed to threadably receive therein an internally threaded lead nut  449  (typical). Each lead nut ( 449  typical) threadably receives therethrough one of first, second and third externally threaded lead screws  430 , 432 , 434 , (see FIGS.  6 , 10  and  31 ) 
     A second and similar, discontinuous, open hollow cylinder  436  is affixed to the outboard surface of the second collar  222  as by means of a locking ring  438  which is disposed in abutting relationship to the hollow cylinder and anchored to the outboard face  440  of the collar as by bolts  442 . As in the first hollow cylinder, within the discontinuities of the hollow cylinder there are mounted fourth, fifth and sixth mounting blocks  444 , 446  and  448 . (see FIGS.  6  and  10 ), respectively. Each mounting block is provided with an internally threaded lead nut  449 , (typical) which is indicated to the lead nuts  449  of the blocks  410 , 412 , 414  except being of opposite handed internal threads. The respective axes of the lead nuts  449  and  449 , are in axial register. One end of one of the first, second and third composite lead screws is threadably received within each pair of requested lead nuts. As depicted, each lead screw  430  (typical) is provided with left hand threads  450  on one of its ends  453  and right hand threads  452  on its opposite end  455 . Each lead screw  430  is a composite of the left hand threaded end and right hand threaded end joined together by a central tubular connector  454  having a smooth outer circumferential surface  457  which is disposed between the inner circumference of the hub  52  and the main shaft  12 . Preferably, each lead screw lies within a respective one of first, second and third outwardly opening grooves  456 , 458  (only the first and second grooves are depicted in the Figures) that are provided along the length of, and on the outer circumferential surface of, the main shaft. It will be recognized that rotation of the several lead screws simultaneously will effect axial movement of the collars  220  and  222 , along with their respective set of segments, toward or away from one another, depending upon the direction of rotation of the lead screws, thereby providing for axial positioning of the respective sets of segments. 
     Outboard of the locking ring  411  on the end  489  of the main shaft there is provided a subassembly for effecting axial adjustment of the width of the drum by effecting simultaneous, directionally selective, rotation of the first, second and third lead screws  430 , 432 , 434 . Referring specifically to FIGS.  6 , 10  and  32 - 36 , this subassembly includes a bell-shaped housing  460  comprising a generally cavitated body portion  462  and an elongated hollow tubular portion  464 . 
     As best depicted in FIGS.  3 , 4  and  33 - 36 , within the interior of the cavitated body portion of the housing there are received first, second and third spur gears  466 , 468  and  470 , respectively which are spaced apart circumferentially of the housing and within respective cavities  472 , 474  and  476 . As depicted in FIG. 6, each of these spur gears is fixedly mounted on one end of a respective one of the lead screws by means of a conventional expanding locking nut  478  (typical) (FIG.  6 ). Outboard of the locking nut, there is provided a thrust washer whose outer circumference fits within a sub-cavity within respective ones of the cavities  472 , 474 , 476  (see FIG. 35) which receive the spur gears  466 , 468 , 470  and serve to rotatably mount the end of the lead screws  430 , 432 , 434  within the housing  460 . One end of each of the first, second and third lead screws is likewise rotatably mounted within their respective cavities (not shown) within the housing. Stabilization of those ends of the lead screws adjacent the housing  460  is enhanced by means of respective pillow blocks  485  (typical) (FIG. 6) that are received in respective radially outwardly opening slots  487  in the end  489  of the main shaft  12 . The lead screws thus extend so axially away from the housing and along substantially the length of the main shaft and within their respective groove in the outer circumference of the main shaft. Thus, the lead screws and the housing rotate in unison with rotation of the main shaft. 
     As depicted, a fourth spur gear  486  is mounted centrally of and in meshing relationship with the first, second and third spur gears  486 , 468  and  470 . This fourth spur gear  486  is keyed  487  on one end  490  of an adjustment pin  492  which is mounted within a flanged sleeve  494  which is pinned  496  through a slot  498  in the sleeve that is in register with a bore  500  in the adjustment pin  492  to the adjustment pin to limit axial and rotational movement of the sleeve relative to the adjustment pin. In turn, the sleeve is rotatably and slidably received within a central bore  502  of the hollow tubular portion of the housing. Bushings  504  and  506  are provided in encircling relationship to the adjustment pin  492  and within the annular space between the outer circumference of the adjustment pin and the outer circumference of the sleeve to slidably mount the adjustment pin within the sleeve to the extent permitted by the length of the slot  498 . When the sleeve and adjustment pin are assembled together and disposed within the housing, the outboard surface  508  of the flange  510  abuts the inboard end of the central bore  502  of the tubular portion of the housing as seen in FIGS. 3 and 4. A coiled spring  511  is interposed between the spur gear  486  which is fixedly mounted on the end of the alignment pin, and the inboard surface  512  of the flange  510  and serves to bias the sleeve  494 , hence the adjustment pin  492 , axially outwardly of the drum. The outer circumferential surface  514  of the flange is provided with notches equally spaced apart about such outer circumferential surface of the flange. A conventional spring pin  516  is countersunk into a cavity within the housing  460  with its outboard end disposed in locking engagement with one of the notches in the sleeve flange when the flange is in abutting relationship to the inboard end of the central bore  502  of the tubular portion  464  of the housing,  460  thereby locking the sleeve against rotation within the housing. On the other hand, when the sleeve and its flange (and the adjustment pin affixed thereto) are forced axially inwardly of the drum against the biasing force of the coiled spring, the flange no longer is in contact with the spring pin  516  and the sleeve is therefore free to be rotated with respect to the housing. 
     Rotation of the adjustment pin  492 , produces rotation of the fourth spur gear  486  which is keyed to the end of the alignment pin. As will be recognized, rotation of the fourth spur gear  486  functions to simultaneously rotate the first, second and third spur gears  466 , 468 , 472  whose gear teeth mesh with the gear teeth of the fourth spur gear  486 . It will be further recognized that rotation of the first, second and third spur gears functions to simultaneously rotate the first, second and third lead screws  430 , 432 , 434  and that rotation of the lead screws within the lead nuts held within their respective mounting blocks associated with the first and second collars functions to move the collars axially of the main shaft. Depending upon the direction of rotation of the lead screws, the collars, and their associated segments, move toward or away from the transverse center plane of the drum simultaneously and coextensively. As the segments of the drum are moved axially, their respective mounting lugs  240 , 259  slide along the rods  160  which extend from the central portion of the drum and in opposite directions from the transverse center plane of the drum. 
     Rotation of the fourth spur gear is effected in the depicted embodiment by accessing the outboard end  520  of the adjustment pin  492  and rotating this pin. To this end, the outboard end  520  of the adjustment pin is configured  522  to receive thereon a conventional socket wrench by means of which the sleeve can be pushed axially inwardly of the drum against the bias of the spring  511  to free the flanged sleeve and the adjustment pin which is pinned to the sleeve for rotation thereof. By reason of the pinned relationship between the adjustment pin and the fourth spur gear  486 , rotation of the adjustment pin effects rotation of the first, second and third spur gears  466 , 468 , 470 , hence simultaneous and coextensive rotation of the first, second and third lead screws  430 , 432 , 434 . As noted, rotation of the lead screws within their respective lead nuts  449  results in axial movement of the first and second collars  220 , 222  in opposite directions. Depending upon the direction of rotation of the lead screws, the movement of the collars is either axially toward or away from the transverse center plane of the drum. This axial movement of the collars, hence the respective sets of segments, is accommodated and stabilized by reason of the sliding nature of the mounting lugs  240  and  259  on the respective rods  160 . Inasmuch as each of the collars  220 ,  222  is non-rotational with respect to the main shaft, the relative circumferential alignment of the several segments of each set of segments is maintained over the course of the axial movement of the collars. Because the left-hand segments and their corresponding right-hand segments are commonly mounted on a respective rod  160 , these left and right-hand segments maintain their positions relative to one another. 
     Recalling that the several rods  160  are themselves mounted for radial movement thereof relative to the rotational axis of the drum, the axial movement of the sets of segments can take place independently of, or simultaneously with, radial movement of the segments. 
     As best seen in FIGS.  3 , 4  and  6 , the hollow end  489  of the main shaft  12  is internally threaded and receives therein an elongated tubular sleeve  530  which is externally threaded at its outboard end  532  to be threadably received within the hollow end  489  of the main shaft. The outboard end of the sleeve terminates in the form of an annular flange  534  whose outer circumference slidably engages the inner circumference of the hollow main shaft adjacent the open end  489  of the shaft. This sleeve further is provided with an annular shoulder  536  at a location inwardly from its open outboard end. A portion  538  of the internal diameter of the sleeve adjacent the shoulder is internally threaded. As best seen in FIGS. 3 and 4, a conventional elongated deceleration member  542  is fitted within the sleeve  530  and includes an externally threaded axial projection  544  on that end thereof adjacent the shoulder  536  of the sleeve and an axially movable piston rod  546  extending axially from the deceleration member toward and abut this the flat end surface  548  of the inboard end  550  of the drive rod  90 . The externally threaded projection  544  on the outboard end of the deceleration member is threaded into the internal threads of the sleeve  530  to fixedly secure the deceleration member within the sleeve. The outboard open end of the sleeve receives therein the bushing  504 , which in turn slidably receives therein the end of the adjustment pin  492 . The extent of permissible insertion of the end of the adjustment pin into the bushing is limited by reason of the end of the bushing engaging face of the fourth spur gear  486 , the deceleration member being thereby fixedly mounted within the hollow main shaft with its piston rod element  548  being disposed adjacent the end of the drive rod  90 . Upon axial movement of the drive rod  90  to the left as viewed in FIG. 32, it will be recognized that the deceleration member serves to dampen such axial movement of the drive rod  90 . This feature of the present invention has been found to materially reduce the noise associated with the metal-to-metal contacts between the drive rod, its associated roller cams  80 , 82 , the engagement of the cams with the helical slots  74 , 76  in the hub  52 , and the associated mechanical movements which move the segments radially inwardly and outwardly of the drum. This feature further prolongs the life of the drum by reducing the severity of the metal-to-metal engagements which occur in the course of operation of the drum. 
     In one embodiment of the present drum, there is provided a counter  549  mounted in the housing  460 . (See FIGS.  32  and  35 - 36 ). This counter is driven by rotation of a shaft  550 , one end  552  of which is operatively connected to the counter and the opposite end  554  of which has fixedly mounted thereon a fifth spur gear  556 . This spur gear is mounted within a cavity  558  in the interior of the housing  460  such that its gear teeth mesh with the gear teeth of the central fourth spur gear  486  so that rotation of the fourth spur gear  486  is translated into a numerical output by the counter. Thus, through the means of this counter subassembly, the operator can at all times obtain a visual indication of the relative axial positions of the two sets of segments. 
     As desired, the tubular portion of the housing  460  may serve as the location for mounting of the drum in the tailstock end (not shown) of a tire making machine as is well known in the art. 
     Whereas the present invention has been described employing specific mechanical elements, one skilled in the art will recognize other equivalent elements which may be employed without adversely affecting the functionality of the present drum.