Abstract:
An apparatus for crimping a stent by segmental radial compression, comprising a stationary base member; a rotatable drive hub which is moveable in relation to the stationary base member; and a crimping head aligned with respect to the stationary base member and to the rotatable drive hub. The crimping head includes at least ten segments. The segments each have a proximal end and an angled distal end with at least one angled side face terminating in an edge of a predetermined length, each segment having a centerline between the proximal and distal ends, each segment having a proximal point and a distal point, the distal point being disposed on the centerline and the proximal point being disposed off the centerline, and the proximal point being pivotally coupled by pins to the stationary base member and the distal point being pivotally coupled by pins to the rotatable hub member. The segments are arranged so that the segment distal ends are disposed adjacent to and a predetermined distance away from a central point and defining a central aperture with a cylindrical dimension. Also, the segment centerlines extend therefrom toward the segment distal ends and are oriented away from the central point. The segment distal ends move closer to the central point upon rotation of the rotatable hub member in a predetermined direction, whereby the stent is disposed around a base substrate, aligned in the central aperture and crimped round the base substrate upon rotation of the rotatable hub.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY 
     This application claims the benefit under 35 U.S.C. §119(e) of co-pending provisional application Serial No. 60/210,319, filed Jun. 8, 2000, which is hereby incorporated by reference. 
    
    
     37 C.F.R. §1.71(E) AUTHORIZATION 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A MICROFICHE APPENDIX, IF ANY 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, generally, to medical devices and medical device manufacturing apparatus and methods. Additionally, the invention relates to holding, compressing, and crimping devices. More particularly, the invention relates to medical stent crimping devices. The invention has particular utility in the medical industry as a device and method for uniformly crimping a balloon expandable or self-expanding metal or non-metallic stents or stent grafts. 
     2. Background Information 
     The state of the art includes various stent crimping devices and methods. The devices include a collet style crimp mechanism, a flat rolling plate style crimp mechanism, loop or coil radial compression (U.S. Pat. No. 6,063,102), a funnel tube style crimping mechanism (U.S. Pat. No. 5,992,000 FIG. 3), a Touhy style silicone elastomeric crimp sleeve (U.S. Pat. No. 6,009,614), and an expandable bladder/elastic tube. The flat rolling plate style crimp mechanism includes an elastomeric surface upon which the stent in place, and a flat plate positioned and adapted to roll over the stent. Weight may be added onto the plate. The rolling action crimps the stent in place somewhat akin to rolling out dough. The expandable bladder is shaped as a sleeve. Fluid is pumped into the bladder to rotatably compress the stent positioned in it. Other U.S. Patents directed to stent crimping technology include U.S. Pat. Nos. 6,063,092, 6,051,002, 6,024,737, 6,018,857, 5,951,540, 5,931,851, 5,672,169, 5,672,169 and 5,626,604. These patents provide background information on stent technology in general and are incorporated by reference for that reason. 
     The known stent crimper devices and methods are believed to have significant limitations and shortcomings. For example, their structure (i.e. bore size in the structure) limits the diameter of the stent. Additionally, they are not able to use a simple process to satisfy the tolerance demands for certain medical applications. For example, they may not be able to accurately, consistently and uniformly crimp the stent in a single step. This is particularly true of stents with small diameters. For this and other reasons, a need exists for the present invention. 
     This invention provides a stent crimper device and method which are believed to fulfil the need and to constitute an improvement over the background technology. The device and method of the present invention makes it possible through a simple process to crimp a balloon expandable or self-expanding metal or non-metallic intravascular or other anatomically placed stents. The present invention does not require a fixed bore size (I.D.) to obtain the final crimped stent profile. The present invention can be designed to crimp operably receive stents having diameters from 30 mm to near zero. It has been found that, to optimize the present invention to crimp coronary stents, the device should be designed to handle stents between 0.5 mm to 5 mm. The present invention is capable of holding tolerances to 0.005″ while providing a uniform extended crimp of between 1 mm and 100 mm in length. 
     Benefits include a reduced cycle time, reduced machine size, repeatability of the crimped stent diameter, security of the crimped stent, and the elimination of a fixed bore size (I.D.) during the crimp process. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a crimping device and method which is well suited for crimping medical stents. 
     In one embodiment the apparatus for radially compressing an article, comprises: 
     a. at least one stationary member; 
     b. at least one rotatable member which is moveable in relation to the stationary member; and 
     c. at least three segments; 
     i. with a proximal end and an angled distal end with at least one angled side face terminating in an edge of a predetermined length, each segment having a centerline between the proximal and distal ends, each segment having a proximal point and a distal point, one said point being disposed on the centerline and one said point being disposed off the centerline, and one said point being pivotally coupled by pins to the stationary member and one said point being pivotally coupled by pins to the rotatable member; 
     ii. the segments being arranged so that the segment distal ends are disposed adjacent to and a predetermined distance away from a central point and defining a central aperture with a cylindrical dimension, and that the segment centerlines extending therefrom toward the segment distal ends are oriented away from the central point; and 
     iii. the segment distal ends moving closer to the central point upon rotation of the rotatable member in a predetermined direction. 
     The apparatus has a first state wherein the segment centerlines are tangentially oriented with respect to the central aperture, and a second state wherein the segment centerlines become radially aligned with respect to the center point and the aperture closes upon rotation of the rotatable member in the predetermined direction. 
     At least four basic arrangements of the proximal and distal points exists: 
     1. The segment distal point is on the center line and coupled to the rotatable member, and the segment proximal point is disposed off the centerline and coupled to the stationary member. 
     2. The segment distal point is on the center line and coupled to the stationary member, and the segment proximal point is disposed off the centerline and coupled to the rotatable member. 
     3. The segment distal point is off the center line and coupled to the rotatable member, and the segment proximal point is disposed on the centerline and coupled to the stationary member. 
     4. The segment distal point is off the center line and coupled to the stationary member, and the segment proximal point is disposed on the centerline and coupled to the rotatable member. 
     For each of these embodiments may be one stationary member and one rotatable member or two stationary members and two rotatable members. 
     The most preferred embodiment of the single stationary member, single rotatable member apparatus for crimping a stent by segmental radial compression, comprises: 
     a. a stationary base member; 
     b. a rotatable drive hub which is moveable in relation to the stationary base member; and 
     c. a crimping head aligned with respect to the stationary base member and to the rotatable drive hub, and including at least ten segments; 
     i. the segments each having a proximal end and an angled distal end with at least one angled side face terminating in an edge of a predetermined length, each segment having a centerline between the proximal and distal ends, each segment having a proximal point and a distal point, the distal point being disposed on the centerline and the proximal point being disposed off the centerline, and the proximal point being pivotally coupled by pins to the stationary base member and the distal point being pivotally coupled by pins to the rotatable hub member; 
     ii. the segments being arranged so that the segment distal ends are disposed adjacent to and a predetermined distance away from a central point and defining a central aperture with a cylindrical dimension, and that the segment centerlines extending therefrom toward the segment distal ends are oriented away from the central point; and 
     iii. the segment distal ends moving closer to the central point upon rotation of the rotatable hub member in a predetermined direction, whereby the stent is disposed around a base substrate, aligned in the central aperture and crimped around the base substrate upon rotation of the rotatable hub. 
     The most preferred embodiment of the dual stationary member, dual rotatable member apparatus for crimping a stent by segmental radial compression, comprises: 
     a. a pair of aligned, stationary base members separated a predetermined distance; 
     b. a pair of aligned rotatable drive hubs which are moveable in relation to the stationary base member and in synchronization with each other; and 
     c. a crimping head aligned with respect to the base members and the drive hubs, and including at least ten segments; 
     i. the segments each having a proximal end and an angled distal end with at least one angled side face terminating in an edge of a predetermined length, each segment having a centerline between the proximal and distal ends, each segment having a proximal point and a distal point, the distal point being disposed on the centerline and the proximal point being disposed off the centerline, and the proximal point being pivotally coupled by pins to the stationary base members and the distal point being pivotally coupled by pins to the rotatable hub members; 
     ii. the segments being arranged so that the segment distal ends are disposed adjacent to and a predetermined distance away from a central point and defining a central aperture with a cylindrical dimension, and that the segment centerlines extending therefrom toward the segment distal ends are oriented away from the central point; and 
     iii. the segment distal ends moving closer to the central point upon rotation of the rotatable hub members in a predetermined direction, whereby the stent is disposed around a base substrate, aligned in the central aperture and crimped round the base substrate upon rotation of the rotatable hub. 
     The invention also provides a method of compressing an article comprising the steps of: 
     a. providing an arrangement of a plurality of segments, each having a predetermined shape with a proximal end and an angled distal end with at least one angled side face terminating in an edge of a predetermined length, each segment having a centerline between the proximal and distal ends, each segment having a proximal point and a distal point, one said point being disposed on the centerline and one said point being disposed off the centerline, and one said point being pivotally coupled by pins to the stationary member and one said point being pivotally coupled by pins to the rotatable member, the segments being arranged so that the segment distal ends are disposed adjacent to and a predetermined distance away from a central point and defining a central aperture with a cylindrical dimension, and that the segment centerlines extending therefrom toward the segment distal ends are oriented away from the central point; and 
     b. placing a stent on a base substrate; 
     c. inserting the stent and base substrate into the central aperture; and 
     d. rotating the rotatable member in a predetermined direction so that the segment distal ends move closer to the central point, whereby the central aperture contacts, compresses and crimps the stent onto the base substrate. 
     The features, benefits and objects of this invention will become clear to those skilled in the art by reference to the following description, claims, and drawings. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a front, plan view of a stent crimping system of the present invention. 
     FIG. 2 is a rear or back plan view of the stent crimping system of FIG.  1 . 
     FIG. 3 is an exploded view of a crimping head utilized in the stent crimping system of FIGS. 1 and 2. 
     FIG. 4 is a perspective view of an individual segment of the stent crimping head which shows certain features in phantom. 
     FIG. 5 is a front view of the segment of FIG.  4 . 
     FIG. 6 is a side view of the segment. 
     FIG. 7 is an end view of the segment. 
     FIG. 8 illustrates an alternative embodiment of a crimping segment of the present invention with a single angle plane and a proximal offset pin aperture. 
     FIG. 9 illustrates an alternative embodiment of a crimping segment of the present invention with a single angle plane and a proximal offset pin aperture. 
     FIG. 10 is a diagram which illustrates variation in tip path of a segment with respect to different pin offset distances from a segment centerline. 
     FIG. 11 is a front plan view of the stent crimping head with an access aperture in an open position. 
     FIG. 12 is a front plan view of the stent crimping head of FIG. 11 with the access aperture in a closed position. 
     FIG. 13 is a front plan view of the stent crimping head of FIG. 11, with a face plate removed to show the position of internal segments corresponding to the open aperture of FIG.  11 . 
     FIG. 14 is a front plan view of the stent crimping head of FIGS. 11 and 12, with the face plate removed to show the position of internal segments corresponding to the closed aperture of FIG.  12 . 
     FIGS. 15A, B and C shows a sequence of movement of an embodiment of the stent crimping head as the crimping aperture proceeds from an open to a closed state, the head embodiment having a proximal offset and being distally driven. 
     FIGS. 16A, B and C shows a sequence of movement of an alternative embodiment of the stent crimping head as the crimping aperture proceeds from an open to a closed state, the head embodiment having a proximal offset and being proximally driven. 
     FIGS. 17A, B and C shows a sequence of movement of a further alternative embodiment of the stent crimping head as the crimping aperture proceeds from an open to a closed state, the head embodiment having a distal offset and being distally driven. 
     FIGS. 18A, B and C shows a sequence of movement of a further alternative embodiment of the stent crimping head as the crimping aperture proceeds from an open to a closed state, the head embodiment having a distal offset and being proximally driven. 
     FIGS. 19A, B and C shows a sequence of movement of a further alternative embodiment of the stent crimping head as the crimping aperture proceeds from an open to a closed state, the head embodiment having a distal offset and being proximally driven by a drive pin contacting an external surface of the segment. 
     FIG. 20 is a perspective view of an alternative embodiment of the stent crimping system of the present invention, wherein the stent crimping head is actuated by a pair of actuators located at the front and back of the head. 
     FIG. 21 is an exploded view of the crimping head utilized in the stent crimping system of FIG.  20 . 
     FIG. 22 is a front view of the stent crimping head of the embodiment shown in FIGS. 20 and 21, with the crimping aperture in an open position and arms a corresponding position. 
     FIG. 23 is a front view of the stent crimping of dual arm embodiment with the crimping aperture in a closed position and arms a corresponding position. 
     FIG. 24 is a top view of the stent crimping head of the dual arm embodiment. 
     FIG. 25 is a bottom view of the stent crimping head of the dual arm embodiment. 
     FIG. 26 is a side view of the stent crimping head of the dual arm embodiment. 
     FIG. 27 shows a perspective view of an exemplary segment in the dual arm embodiment having an increased length for longer stents. 
     FIG. 28 shows a front view of the segment of FIG.  27 . 
    
    
     DETAILED DESCRIPTION 
     The stent crimping device and method is suitable to uniformly crimp a balloon expandable or self-expanding metal or non-metallic stents or sent grafts. A crimped stent includes a core such as a balloon catheter and a sheath. The stent is uniformly crimped to the collapsed balloon along the length, preferably within a diameter tolerance of 0.005 inches. The apparatus and methods of the invention may also be used or adapted for use in securely gripping, holding and/or selectively radially compressing other articles. The apparatus and methods are also useable or adaptable for use in crease and/or fold structures such as balloons, to form a wide variety of radial compression devices (such as within a machining center so that the machinists will not have to replace collets), and to form or create a stent retention mechanism that retains the stent without applying radial forces against the balloon, thus enabling the balloon or sheath to be retracted. 
     Referring to FIGS. 1 and 2, an embodiment of the system  10  for crimping stents and the like generally includes a crimp head  11 , a base  12 , and an actuator  13 . The crimp head  11  is disposed on the base surface  12  and primary functions to accept and crimp stents. The actuator  13  powers the crimp head. The actuator  13  preferably includes a drive mechanism  15 , a linkage assembly  16  communicatively connected to the drive mechanism  15 , an actuation arm  17  communicatively connected to the linkage assembly and to the crimping head  11 , and an actuation control system  18  communicatively connected to the drive mechanism  15 . The actuator  13  may be hand and/or foot operable by an operator. The actuator  13  is preferably a pneumatic system. Alternatively, hydraulic, mechanical, electrical, or electromechanical actuators may be used consistent with the basic teachings of the invention. The base  12  is preferably a particularized table structure having a flat work surface of a predetermined area and supported, as shown by supports or legs  14  a predetermined distance above the ground optimized for performing crimping function. It is within the purview of the invention that the crimping head  11  may be disposed on an existing table, bench or other work surface. 
     Additional systems, assemblies or mechanisms may be added to the basic system outlined above. These additional systems include, but are not limited to handling and alignment control and/or indication devices, pressure regulation and/or indication systems, calibration systems, control devices such as mechanical stops, vision assistance, laser micrometers, vacuum evacuation systems, interchangeable crimp heads, and crimp dwell timers. Further, the system  10  may be controlled by an operator or automated. 
     Referring also to FIG. 3, the crimp head  11  shown has a relatively compact, preferably rectilinear, configuration. The crimp head  11  basically comprises a base or housing  22 , a drive hub  23 , a radial compression wedge  24 , a plurality of pivot pins  25 , a plurality of drive pins  26 , and a face plate or cover  27 . The base  22  has a predetermined depth or thickness with a wedge chamber  28 , a hub chamber  29 , and a hub aperture  30 . The hub  23  has a stem portion  31  and a plate portion  32 . The wedge  24  consists of a plurality separate segments  33 . The cover  27  has a centrally disposed aperture  34 . 
     The hub  23  is constructed of rigid material, preferably metallic. The stem portion  31  of the hub  23  has a cylindrical configuration with a predetermined length and circumference such that it extends through the hub aperture  30  of the base  22 . The stem portion  31  extends a predetermined distance out of the base  22  and is connected to the actuator arm  17 . In this embodiment, the actuator arm  17  moves in a counter-clockwise direction during actuation to perform a holding, compressing or crimping function. The base  22  is also constructed of a rigid material, preferably metallic. The plate portion  32  of the hub  23  also has a cylindrical configuration with a predetermined depth and circumference such that it is housed within the hub chamber  29  of the base  22 . The hub  23  is rotatable with respect to the base  22 . When the hub plate portion  32  is operatively disposed in the hub chamber  29 , its front face is approximately flush with the back wall of the wedge chamber  28 . The wedge  24  has a roughly cylindrical configuration with a predetermined maximum depth and circumference such that it is housed within the wedge chamber  28  of the base  22 . The cooperating depths and circumferences of the wedge  24  and wedge chamber  28  respectively, permit the wedge  24  to move within the wedge chamber  28  during a crimping operation. The pivot pins  25  are constructed of a rigid material, preferably metallic. The pivot pins  25  are cylindrical and have a predetermined length and diameter. The pivot pins  25  are preferably disposed in cylindrical slots or bores  35  in the back wall of the wedge chamber  28  of the base  22 . The pins  25  are preferably held in the slots  35  via a frictional fit. The slots  35  are disposed in a circular pattern equally spaced apart a predetermined distance from each other and from the center of the wedge chamber  28 . The drive pins  26  are constructed of a rigid material, preferably metallic, and have a cylindrical configuration with a predetermined length and diameter. The drive pins  26  mate with slots or bores  36  in the plate portion  32  of the hub  23 . The drive pins  26  preferably have a slightly smaller horizontal dimension than that of the slots  36  to permit removal of pins  26  therefrom. Each slot  36  preferably has a cylindrical configuration which is slightly elongated along an axis extending from the center of a center of the hub  23 . The slots  36  are disposed in a circular pattern equally spaced apart a predetermined distance from each other and from the center of the hub  23 . The number of pivot pins  25  and drive pins  26  is equal to the number of segments  33  in the wedge  24 , and each wedge  24  is associated with and pivotally coupled to one pivot pin  25  and one drive pin  26 . The pivot pins  25  and drive pins  26  mate with corresponding slots or bores in the back face of the wedge segments  33 . When the wedge  24  is operatively disposed within the wedge chamber  28 , the face plate  27  fits over the base  22  generally flush with a raised central portion  37  of the front face of the wedge  24  formed by the segments  33 . 
     Referring to FIGS. 4-7, each segment  33  preferably has a rectilinear configuration with a proximal end  40 , a distal end  41 , a front face  42  and a rear face  43 . A proximal end face  44  is preferably flat and rectangular with a predetermined area. The distal end  41  preferably terminates in a thin edge  45  formed at the intersection of side faces  46  and  47 . Although the distal end  41  is shown to have a rectilinear, flat and uniform dimensions with a particular dimension, it may be alternatively configured with a curvilinear, non-flat, textured, and/or non-uniform surfaces (such as stepped geometries and various specialized surface textures, for example) in a variety of dimensions, including a truncated end, to provide particular gripping, compression or crimping function and depending upon the article configuration and material. The width of edge  45  is variable between approximately 5 and 100 mm and is based upon the length of the stent to be crimped or article to be engaged, held and/or radially compressed. Preferably, both side faces  46  and  47  are angled and equivalent. FIG. 5 shows optional incut portion  53  of face  47 , which face is disposed away from the wedge  24  actuation direction. This provides tip angle tolerance during disactuation of the wedge  24 . FIGS. 8 and 9 show alternative segment embodiments  53  and  54  wherein respective single faces  55  and  56  are angled and opposing respective faces  57  and  58  are not angled. Returning to the preferred embodiment, front face  42  has a proximal lower portion  48  and a distally oriented raised or extended portion  49 . A combination of the raised portions  49  of the faces  42  of all of the segments yields center portion  37 . Center portion  37  provides optimum wedge  24  stability with minimal friction. 
     Rear face  43  has a proximally oriented pivot slot  50  and a distally oriented drive slot  51 . The center point of the pivot slot  50  is disposed a predetermined distance “X” away from a centerline  52  of the segment  33  which runs from the center distal point of the segment  33  (in this embodiment edge  45 ) to the center proximal point. Pivot slot  50  has a predetermined vertical depth and cylindrical configuration for mating with the pivot pin  25  which is coupled to the stationary base  22 . The pivot slot  50  preferably has a predetermined diameter which is slightly greater than that of the pivot pin  25  to permit removal of the pivot pin  25  therefrom. The center point of the drive slot  51  is disposed on the centerline  52 . Drive slot  51  has a predetermined vertical depth and cylindrical configuration. The drive pin  26  is preferably friction fitted into the drive slot  51 . In this configuration, each drive pin  26  mates with a respective radially elongated cylindrical slot  36  of the rotatable drive hub  23 . The radially elongated cylindrical slot  36  permits slight radial movement of the drive pin  26 . This preferred structure provides longitudinal or radial clearance for any drive pin  26  which is not creating sufficient geometric offset in relation to an angle side  46  or  47  of a segment  33  during actuation. An acceptable alternative arrangement it to slightly radially elongate the segment  33  drive slot  51  and to construct the drive hub  23  slot  36  as a circle. 
     In general, pin offset from centerline provides tolerance for movement of the segments  33  through the operating range of the crimping wedge  24 . This tolerance permits opening of the crimping head, the process of which is described below. Pivot pin  25  offset distance from centerline  52  preferably ranges from 0.05 to 0.200 inches. A preferred pivot pin offset distance is 0.050 inches for medium and large diameter crimping applications. Larger offset distances provide advantages such as reduction of tip wear and damage minimization during crimping of small diameter stents and other articles. Referring to FIG. 10, increased pin offset distances from the segment centerline decreases required tolerance at the close diameter and less segment friction within the operating range of the crimp head due to plane shifting. The tip paths of a segment with different pivot pin offset are shown. 24 degree angle planes shift back from center 0.006 at a 5 mm open position with a 0.125 inch pin offset distance. With the pin offset at 0.050 inch the tip path line is flat in comparison to a horizontal reference line. The tolerance between segments must increase with the 0.050 inch offset distance enough to reduce internal friction and concerns of wear. Tolerance allows the tips to flex and are vulnerable to damage, particularly during use with a small article. By increasing the offset to 0.125 inches, the crimp head moves freely from a working diameter of 5 mm to 0.5 mm without excessive internal friction, with reduced concerns of wear, with no increase of introduced shear, and with tightness in the closed position. The increase pin offset allows the angle planes to pull back more rapidly in relation to the actuation hub position. At a 0.052 inch open diameter, the exemplary tip is shifted back 0.001 inches. The advantage to having the segments interfere at the closed position is reduced tip flex, which allows the system to crimp onto a small diameter mandrel without segment damage. A 0.125 inch offset distance is preferable to 0.200 inch or higher offset distances due to large gaps which will occur in the open position at such offsets. 
     The segments  33  are preferably constructed of a polymeric material such as Delrin or Delrin AF, polycarbonate, PEEK or Ertalyte. Alternatively, they may be constructed of a thermoplastic material, a ceramic material, a composite material, or a metallic material such as stainless steel. 
     The segments  33  have a preferred length from distal to proximal end of about 1.5 inches, a preferred width of about 0.375 inches and preferred depths or thickness of 0.625 inches minimum and 0.750 maximum. The distal slot center is about 0.441 inches from the distal tip and the proximal slot center is about 1.375 inches from the distal tip. A preferred angle for the angled faces is about 24 degrees. 
     The wedge  24  embodiment shown has fifteen segments  33 . The number of segments  33  is variable. Three, four, five, six, eight, 10 and 12 segment wedges are also possible depending upon the desired holding, compressing or crimping function desired and depending upon the subject article configuration and material. 
     Referring also to FIGS. 11-14, in operation, the wedge  24  has an initial, fully open state with centrally disposed crimping aperture  62 , (best shown in FIGS.  11  and  13 ) a fully closed state, wherein the aperture  62  has a minimum size (best shown in FIGS.  12  and  14 ), and a plurality of intermediate states between the initial fully open state and the fully closed state wherein the aperture  62  becomes progressively smaller. The maximum diameter of the aperture  62  is variable up to approximately 12.0 mm. The minimum diameter is also variable, approaching zero. The length or depth of the aperture  62  is also variable between approximately 1 mm and 100 mm. A stent to be crimped or another article to be engaged and/or radially compressed is inserted and longitudinally advanced a desired distance into the aperture  62  in the initial, open state. The stent is crimped by rotating the actuation arm  17  counter-clockwise, which contracts the aperture  62 . Contraction causes the aperture  62  wall to contact and exert a radially compressive force on the stent. The stent diameter is reduced a desired amount and engages a catheter body or another structure as desired in a stent manufacturing process. At the desired reduced diameter, the actuator arm  17  is held in position for a desired dwell time, typically between 0 and 20 seconds. Subsequently, the actuator arm  17  is rotated clockwise to expand the aperture  62  and release engagement of the stent. The stent and related structure is retracted and removed from the aperture  62 . 
     Still referring to FIGS. 11-14, the crimping aperture  62  has a substantially circular horizontal dimension and a predetermined length which yields a substantially cylindrical longitudinal dimension. As the aperture  62  contracts and becomes smaller, the periphery of the aperture  62  radially moves towards the longitudinal center axis  63  of the aperture  62  in a substantially uniform manner, whereby the aperture  62  wall maintains a substantially cylindrical configuration through the closing process. Uniform compression is the result of the interaction primarily of the plurality of segments  33  and the pins  25  and  26 , in concert with the respective base  22  and hub  23 . In an open state, where aperture  62  exists, the centerlines  52  of the respective segments  33  do not radially extend out from the central axis point  63 . During actuation, the centerlines  52  converge towards the central axis  63 . In the fully closed state, the centerlines  52  extend radially outward from the central axis point  63 . This process brings the distal portions  41  of the segments  33  closer to the center until ultimately the distal most portion of each segment, in this embodiment the edges  45 , essentially contact the central axis point  63 . Due to the symmetry of the wedge  24  elements, each segments behaves identically, and the closure process is highly uniform. 
     The above mentioned segmental centerline  52  convergence process result from pivotal movement of the distal portion  41  of each segment  33  with respect to the stationary proximal portion  40  of the segments  33 . The drive hub  23  rotates counter clockwise with respect to the stationary base  22 . The distal portions  41  of the segments  33  are moved or driven by the drive hub  23 , which is pivotally coupled to each segment  33  by the drive pins  26  mated with slots  36  and  51 . The proximal portions  40  of the segments  33  are held in a stationary position, but allowed to pivot, by the base  22  which is coupled to each segment  33  by the pivot pins  25  mated with slots  35  and  50 . 
     The segmental radial compression apparatus and process with distally driven, on-centerline drive pins and proximal, off-centerline pivot pins is further illustrated in FIGS. 15A-C. Wedge  70  is identical to wedge  24  of the previous embodiment except that is has 10 segments  71  instead of 15. Proximal portions of the segments  71  are pivotally coupled to a stationary base  72  by pivot pins  73  which are disposed off centerline  78  to the left (towards the direction of drive hub  74  rotation). Distal portions of the segments  71  are coupled to a driven (counter clockwise rotatable) hub  74  by drive pins  75  which are disposed on centerline  78 . The drive pins  75  are permitted a slight amount of radial movement with respect to the drive hub  74  or to the segment  71  via elongated slotting previously described. FIG. 15A illustrates a first state with fully open aperture  76 . The centerlines  78  of the segments  71  are not radially aligned and the distal most points of the segments are spaced from wedge&#39;s central axis. FIG. 15B illustrates a second, intermediate state wherein the hub  74  is traveling. The centerlines of the segments  71  are still not radially aligned. The distal most points of the segments are approaching wedge&#39;s central axis  77 . FIG. 15C illustrates a final state where the aperture is closed. The centerlines of the segments  71  are aligned and radiate from the central axis  77 . The aperture is fully closed. 
     FIGS. 16A-C illustrates an alternative embodiment of the segmental radial compression apparatus and process of the present invention with proximally driven, off-centerline drive pins and distal, on-centerline pivot pins. Wedge  80  has 10 segments  81 . Proximal portions of the segments  81  are coupled to a driven (clockwise rotatable) plate  82  by drive pins  83  which are disposed off centerline  88  to the left (against the direction of drive plate  82  rotation). Distal portions of the segments  81  are pivotally coupled to a stationary hub  84  by pivot pins  85  which are disposed on centerline  88 . The pivot pins  85  are permitted a slight amount of radial movement with respect to the stationary hub  84  or to the segment  81  via elongated slotting previously described. FIG. 16A illustrates a first state with fully open aperture  86 . The centerlines  88  of the segments  81  are not radially aligned and the distal most points of the segments  81  are spaced from wedge&#39;s central axis. FIG. 16B illustrates a second, intermediate state wherein the hub  84  is traveling. The centerlines of the segments  81  are still not radially aligned. The distal most points of the segments are approaching wedge&#39;s central axis  87 . FIG. 16C illustrates a final state where the aperture is closed. The centerlines of the segments  81  are aligned and radiate from the central axis  87 . The aperture is fully closed. 
     FIGS. 17A-C illustrates an alternative embodiment of the segmental radial compression apparatus and process of the present invention with distally driven, off-centerline drive pins and proximal, on-centerline pivot pins. Wedge  90  has 10 segments  91 . Proximal portions of the segments  91  are pivotally coupled to a stationary base  92  by pivot pins  93  which are disposed on centerline  98 . The pivot pins  95  are permitted a slight amount of radial movement with respect to the stationary base  92  or to the segment  91  via elongated slotting previously described. Distal portions of the segments  91  are coupled to a driven (counter-clockwise rotatable) drive hub  94  by drive pins  95  which are disposed off centerline  98  to the left (towards the direction of drive hub  94  rotation). FIG. 17A illustrates a first state with fully open aperture  96 . The centerlines  98  of the segments  91  are not radially aligned and the distal most points of the segments  91  are spaced from wedge&#39;s central axis. FIG. 17B illustrates a second, intermediate state wherein the hub  94  is traveling. The centerlines of the segments  91  are still not radially aligned. The distal most points of the segments are approaching wedge&#39;s central axis  97 . FIG. 17C illustrates a final state where the aperture is closed. The centerlines of the segments  91  are aligned and radiate from the central axis  97 . The aperture is fully closed. 
     FIGS. 18A-C illustrates an alternative embodiment of the segmental radial compression apparatus and process of the present invention with proximally driven, on-centerline drive pins and distal, off-centerline pivot pins. Wedge  100  has 10 segments  101 . Proximal portions of the segments  101  are coupled to a driven (clockwise rotatable) plate  102  by drive pins  103  which are disposed on centerline  108 . The drive pins  103  are permitted a slight amount of radial movement with respect to the driven plate  102  or to the segment  101  via elongated slotting previously described. Distal portions of the segments  101  are pivotally coupled to a stationary hub  104  by pivot pins  105  which are disposed off centerline  108  to the left (against the direction of drive plate  102  rotation). FIG. 18A illustrates a first state with fully open aperture  106 . The centerlines  108  of the segments  101  are not radially aligned and the distal most points of the segments  101  are spaced from wedge&#39;s central axis. FIG. 18B illustrates a second, intermediate state wherein the hub  104  is traveling. The centerlines of the segments  101  are still not radially aligned. The distal most points of the segments are approaching wedge&#39;s central axis  107 . FIG. 18C illustrates a final state where the aperture is closed. The centerlines of the segments  101  are aligned and radiate from the central axis  107 . The aperture is fully closed. 
     FIGS. 19A-C illustrates an alternative embodiment of the segmental radial compression apparatus and process of the present invention with proximally driven, off-centerline drive pins, which are disposed laterally to the side of the segments, and distal, off-centerline pivot pins. Wedge  110  has 10 segments  111 . Proximal portions of the segments  111  are driven (clockwise rotatable) plate  112  by drive pins  113  which are disposed off centerline  118 . In this embodiment, in contrast to the embodiments shown in FIGS. 19A-C, the drive pins  113  are not captured by slots in the body portions of the segments  111 . Instead, the drive pins  113  are disposed to the side of the segments  111  and contact the sides of the segments at a proximal region to drive them. Distal portions of the segments  111  are pivotally coupled to a stationary hub  114  by pivot pins  115  which are also disposed off centerline  118 . FIG. 19A illustrates a first state with fully open aperture  116 . The centerlines  118  of the segments  111  are not radially aligned and the distal most points of the segments  111  are spaced from wedge&#39;s central axis. FIG. 19B illustrates a second, intermediate state wherein the hub  114  is traveling. The centerlines of the segments  111  are still not radially aligned. The distal most points of the segments are approaching wedge&#39;s central axis  117 . FIG. 19C illustrates a final state where the aperture is closed. The centerlines of the segments  111  are aligned and radiate from the central axis  117 . The aperture is fully closed. 
     The apparatus and methods are useable with variable width articles ranging from 0.5 mm to 5 mm to accommodate both long and short stents. To uniformly crimp a longer stent, it may be desirable to apply a crimping force at both sides of a segment. Referring to FIGS. 20 and 21, an embodiment of the system  125  for crimping relatively longer stents and the like generally includes a crimp head  126 , a base  127 , and an actuator  128 . The crimp head  126  is disposed on the base surface  127  and primary functions to accept and crimp stents. The actuator  128  powers the crimp head  126 . The actuator  128  preferably includes a drive mechanism, a linkage assembly communicatively connected to the drive mechanism, actuation arms  129 A and B which are communicatively connected to the linkage assembly and to the crimping head  126 , and an actuation control system  130  communicatively connected to the drive mechanism. The actuator  128  may be hand and/or foot operable by an operator. The actuator  128  is preferably a pneumatic system although other types of systems may be used. The system  125  further includes a stent handling system  132 . Additional systems, assemblies or mechanisms may be added to the basic system  125 . 
     Referring also to FIGS. 22-26, the crimp head  126  shown has a relatively compact, preferably rectilinear, configuration. The crimp head  126  basically comprises a pair of base or housing plates  131 A and B, a pair of drive hubs  133 A and B, a radial compression wedge  134 , two sets (each set including a plurality of pins, preferably 15) of pivot pins  135  A and B, two sets of drive pins  136  A and B, and a pair of separator plates  137 A and B of a predetermined width which couple the base plates  131 A and B. The base plates  131  have a predetermined thickness with a central hub apertures  139 A and B. The hubs  133  have an annular configuration with a flat face portion. The wedge  134  consists of a plurality separate segments  140 . 
     The hubs  133  are constructed of rigid material, preferably metallic. The hubs  133  are preferably connected to respective annular roller bearings  141 A and B. The hubs  133  are connected to respective actuator arms  129 A and B, preferably via respective thrust washers  144 A and B. In this embodiment, the actuator arms  129  move in a counter-clockwise direction during actuation to perform a holding, compressing or crimping function. The base plates  131  are also constructed of a rigid material, preferably metallic. The hubs  133  are rotatable with respect to the base plates  131 . The wedge  134  has a roughly cylindrical configuration with a predetermined maximum depth and circumference such that it is housed between the base plates  131 . The pivot pins  135 A and B mate with respective, aligned pivot slots  142 A and B in base plates  131 A and B, and further to respective, aligned pivot slots  145 A and B in the front and rear faces of the segments  140  (at their proximal ends). The drive pins  136 A and B mate with respect, aligned drive slots  143 A and B in the drive hubs  133 A and B, and further to respective, aligned drive slots  146 A and B in the front and rear faces of the segments  140  (at their distal ends). 
     System  125  shown in FIGS. 20-28 functions in a similar manner to that of system  10  shown in FIGS. 1-3. In a normal mode, the actuation arms  129 A and B are synchronized to move together to apply a uniform force along the entire edge of each of the relatively large wedges  140 . Alternatively, the actuation arms  129 A and B may be differentially actuated to provide a variable compression along the length of the wedges  140 . 
     The crimping apparatus and method of the present invention is adaptable with thermal capability to operate at temperatures ranging between 37° C. and 300° C. by placing heater cartridges in the segments through its back. This may be used to heat set stainless steel balloon expandable stents. The stent crimping devices  10  and  125  are adaptable to compensate for thermal expansion. Further, the apparatus and methods are adaptable with cryo capability to operate at temperature ranging between −200° C. and −37° C. Liquid nitrogen my be used to cool the segments or to cool the housing plates. Alternatively, the entire head may be placed in a cryo chamber. The cryo capability may be used for Nitinol self-expanding stents. The colder temperatures causes the crimped Nitinol stent to stay at the reduced diameter. Additionally, it is believed that the colder temperatures makes Nitinol more malleable which reduces fatigue. 
     The descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with the preferred embodiment or embodiments thereof, it should be understood that there may be other embodiments which fall within the scope of the invention as defined by the following claims. Where a claim, if any, is expressed as a means or step for performing a specified function it is intended that such claim be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof, including both structural equivalents and equivalent structures, material-based equivalents and equivalent materials, and act-based equivalents and equivalent acts.