Abstract:
An internal surface chucking mechanism (ISM) for gripping and for releasing an internal surface of a workpiece (W) in process on a processing machine is configured for reversible exchange with an external surface chucking mechanism (EXS) dedicated to grip an external surface of the workpiece. The ISM fits machinery where the workpiece is rotating and is non-rotating, in a first mode with the EXS, and in a second mode with the ISM, and vice-versa. A fluid conduit inside the ISM provides fluid, such as oil, for exhaust adjacent and opposite the workpiece. An appropriately oriented exit outlet ( 353 ) directs a stream of fluid to impinge on the workpiece, to eject it from the ISM when released from grip. The fluid cools and lubricates both the ISM and the workpiece.

Description:
TECHNICAL FIELD  
       [0001]     The invention relates to an internal surface chucking mechanism (ISM) and to a method for holding a workpiece in a processing machine, to the ability of reversible exchange of the ISM with an external surface chucking mechanism (EXS), and to the use of a stream of fluid exiting from the inside of the ISM to eject the workpiece, to cool and lubricate the workpiece and the ISM, and to prevent the ingress of matter.  
       BACKGROUND ART  
       [0002]     In general, a processing machine for holding a workpiece in process is supplied with an external surface chucking mechanism, referred to below as EXS. Although well known to the art, an EXS is first described and shown in  FIG. 1  for purpose of reference. Even though the invention is applicable to multiple types of workpiece processing machines, the examples provided below refer to turning machines, such as lathes.  
         [0003]      FIG. 1  illustrates a prior art spindle assembly  1  housing an EXS. Three parts of the spindle assembly, which come in contact with the EXS, are referred to as the interface components, and are described below. The operation of the spindle assembly  1 , of the interface components, and of the EXS, is controlled by commands given by, or to, the processing machine. The processing machine, which is not shown in  FIG. 1 , and the spindle assembly  1 , are not described since both are well known to the art.  
         [0004]     The interface components include a spindle  3 , a cap-nut  5 , and a push rod  7 , all coming in direct contact with the EXS and with the IMS, and described below. It is understood that the interface components and the EXS are rotative in the case of a lathe.  
         [0005]     The spindle  3  is configured as a hollow tube with an inside  3 IN, and a generally smooth constant outer diameter, defining a longitudinal axis A. The spindle  3 , with an open front portion  9  and a back portion  11  defines directions as respectively, a front F or a forward direction F, and a back B, or rear, or backward direction B, common to the orientation of the parts of the spindle  3  in the various Figs. The open front portion  9  of the spindle  3  with a front face  9 F, has an inner diameter  9 ID larger than the inner diameter  11 ID of the back portion  11 , forming a front facing arresting step  13  which separates between the front portion  9  and the back portion  11 . The front extremity of the spindle  3  is covered with an external screw thread  9 ST.  
         [0006]     The cap-nut  5  has an open back end with an internal screw thread  5 ST mating the screw thread  9 ST of the spindle  3 . A restriction with an inner diameter  6  starting to the front of the internal screw thread  5 ST forms an arresting step  15  protruding radially inward and facing backward. The front end of the cap-nut  5  has a bottom  19  pierced by an opening bore  17  smaller than the inner diameter restriction  6 . Means for gripping the cap-nut for attachment to and unscrewing from the spindle  3  are not shown in the Figs. When in engagement with the screw thread  9 ST of the spindle  3 , the arresting step  15  on the inside of the cap-nut  5 , stops the cap-nut in abutment with the front face  9 F of the spindle  3  and confines the EXS to the inside  3 IN of the spindle.  
         [0007]     The push rod  7 , which is a tube open towards the front F, of which only a portion with a front face  7 F is seen in  FIG. 1 , is concentrically supported on the inside  3 IN of the back portion  11  of the spindle  3 . The push rod  7  is operable in axial translation within the spindle  3 , from a first extreme backward retracted position, not shown in  FIG. 1 , to a second extreme forward extended position  21 , in which the front face  7 F of the push rod  7  protrudes forward of the arresting step  13 , into the front portion  9  of the spindle  3 , to positively operate the EXS.  
         [0008]     The EXS is built essentially of a collet actuator  23 , of an outer surface hollow gripping chuck  25 , or OSC  25 , and of a helical spring  27 , all better seen in  FIG. 2 , where the spindle assembly  1  is deleted.  
         [0009]     The hollow, substantially axi-symmetric collet actuator  23  is received for sliding translation and retained inside the front portion  9  of the spindle  3 , forward of the arresting step  13 . The motion of the collet actuator  23  is limited backward, by the arresting step  13 , and forward, by the bottom of the cap-nut  5 .  
         [0010]     On the inside, the collet actuator  23  has a generally constant collet actuator inner cylindrical surface  31  of uniform inner diameter, but for a thick lip  33  at the extremity of the back portion, and a conical opening  35  in the front portion. The thick lip  33  protrudes radially inward to form both a front facing spring shoulder  33 F sufficient to arrest a back end  27 B of the helical spring  27  disposed inside the collet actuator inner cylindrical surface  31 , and a back facing push rod shoulder  33 B for receiving the front face  7 F of the push rod  7 .  
         [0011]     In the front portion of the collet actuator  23 , an inner conical opening  35  forms a female cone wide open at the front and tapering backward to the collet actuator inner cylindrical surface  31 . On the outside, the collet actuator  23  has a generally cylindrical smooth outer surface  37  with a constant outer diameter but for a low flange  39  protruding radially outward at the front portion extremity.  
         [0012]     The outer surface chuck  25 , or OSC  25 , is hollow and positioned in concentric alignment inside the collet actuator  23 . The outside of the OSC  25  has a front portion with a short front cylindrical portion  41  and a conical male flange  43 , and a back portion. The back portion of the OSC  25  has a cylindrical smooth outer diameter surface  45  terminating in a back extremity OSC base  47  resting on the front end  27 F of the helical spring  27 .  
         [0013]     The male conically shaped flange  43  protrudes radially outward of the front cylindrical portion  41  outer diameter to form a front facing jaw shoulder  49 , and tapers backward, to the outer diameter surface  45 . The male conically shaped flange  43  conforms to the internal female cone of the opening  35  accommodated in the collet actuator  23 .  
         [0014]     The short front cylindrical portion  41 , to the front of the jaw shoulder  49  is freely received inside the opening bore  17  concentrically piercing the thickness of the cap-nut bottom  19  of the cap-nut  5 . It is the cap-nut bottom  19  which retains the front facing jaw shoulder  49  inside the collet actuator  23 , and therewith, the whole EXS.  
         [0015]     The front portion of the OSC  25  is slit radially from the front cylindrical portion  41  to the back of the conical male flange  43  to form a plurality of jaws  51 , e.g. three jaws  51 , separated from each other by slits  53 , for gripping outer surfaces of a workpiece. Normally, the jaws  51  are open, but the exertion of radial inward forces close the jaws inward. It is the frontward motion of the collet actuator  23  that closes the jaws  51  on the workpiece, not shown in  FIG. 1 .  
         [0016]     It is noted that the EXS resides in a space referred to as an inner chamber  70 , defined as the volume enclosed within both the front portion  9  of the spindle  3  and of the cap-nut  5 , and aligned with the axis A. The parts of the EXS housed inside the inner chamber  70 , all coaxially aligned, releasable and retrievable, come in contact solely with the interface components, thus with the cap-nut  5 , the spindle  3 , and the push rod  7 .  
         [0017]     It is also noted that in the description of the interface components, keys or pins possibly used for the coupling of jointly rotating parts and for relative translation displacement have not been mentioned and will not be described below, for the sake of simplicity.  
         [0018]     In operation, when the push rod  7  resides in the first extreme back retracted position, the back end  27 B of the helical spring  27  biases the collet actuator thick lip  33  against the front facing arresting step  13 , while the front end  27 F of the helical spring  27  urges the jaw shoulder  49  of the OSC  25  against the inner bottom  19  of the cap-nut  5 . Thereby, the jaws  51 , now not urged inwardly by the inner female front conical opening  35  of the collet actuator  23 , are free to reside in their normally open position.  
         [0019]     To grip an outer surface of a workpiece, not shown in  FIGS. 1 and 2 , the push rod  7  is commanded to translate forward, to push the collet actuator  23  forward. Thereby, the female front conical opening  35  acts upon the male cone  43  and closes the jaws  51  radially inward to grip an outer surface of a workpiece.  
         [0020]     In practice, when an EXS grips an outer surface of a workpiece, and the jaws of the EXS cover an external portion of that workpiece, inevitably, the covered portion is prevented from being processed. Furthermore, the jaws of the EXS may leave unallowable marks that mar the outer surface finish of the workpiece. Moreover, a short workpiece is difficult to grip with an EXS.  
         [0021]     In U.S. Pat. No. 5,816,581, Chase discloses an “Inner Diameter Chuck Providing Registration and Operable by Push or Pull to Attach a Workpiece”, which in other words, relates to an inner surface gripping chuck for retaining a workpiece by an inner diameter. Chase opts for the conversion of a processing machine by mounting a special purpose structure thereon with “ . . . an attached extender  25 ” together with the addition of numerous other parts.  
         [0022]     In workpiece processing facilities, an internal surface chucking mechanism (ISM), or Inner Diameter Chuck as called by Chase, is often required and very useful. One problem is that available financial resources may prohibit the acquisition and the dedication of machinery and equipment solely to the purpose of inner surface gripping, as required by the teachings of Chase.  
         [0023]     Another problem with the solution provided by Chase is that the geometry and initial external configuration of the processing machine is altered, causing at least inconvenience, if not demanding replacement of jigs, fixtures and gauges.  
         [0024]     A further problem with the solution provided by Chase is that the implementation thereof is cumbersome, expensive and time consuming.  
       DISCLOSURE OF THE INVENTION  
       [0025]     The present invention provides a method and an ISM product permitting the in situ reversible exchange of an EXS with an ISM for operation with a processing machine, such as inside a spindle assembly  1 . The reversible exchange is as easy as the routine fast exchange, e.g., of a cutting tool in the case of a lathe. Advantage is taken of the inner chamber  70  existing in the spindle assembly  1  of a processing machine, from which the EXS is retrieved and replaced by an ISM. The ISM is constructed with only a few parts without actually enlarging and adding to the maintenance expenses of the tooling inventory. Evidently, the need for dedicated facilities is avoided since the ISM transforms existing equipment into adaptive machinery by allowing replacement of an EXS with an ISM and vice versa.  
         [0026]     Furthermore, a fluid flow communication conduit is entered to the inside of the ISM and fluid exit bores are appropriately added. The stream of fluid exiting the ISM, emanating from a source of fluid under pressure, ejects the workpiece chucked in the processing machine when the grip thereon is released. Moreover, the stream of fluid cools and lubricates both the ISM and the workpiece and prevents ingress of outside matter into the ISM.  
       SUMMARY  
       [0027]     It is an object of the present invention to provide an internal surface chucking mechanism (ISM) comprising a collet for gripping an internal surface accommodated in a workpiece.  
         [0028]     It is another object of the present invention to provide an ISM configured for exchangeable reversible replacement with a commercially available external surface chucking mechanism (EXS) comprising a collet for gripping an external surface of the workpiece. By exchanging and replacing an EXS with an ISM, and vice-versa, the processing machine is converted from a first state to a second state.  
         [0029]     It is a further object of the present invention to provide an ISM with a passage for fluid flow supplied by a source of fluid under pressure and exiting the ISM adjacent and opposite the workpiece, to eject the workpiece from the ISM when grip thereon is released.  
         [0030]     It is yet another object of the present invention to provide an ISM and a method for implementing such an ISM comprising a coupling mechanism activable for gripping and for release of a workpiece in process on a processing machine, the workpiece defining an external surface and an internal surface configured for access from the outside. The processing machine comprises an inner chamber defining an axis and a volume of space inside the processing machine, 
        an external surface chucking mechanism (EXS) releasably and retrievably retained in axial alignment in the inner chamber and configured for gripping and for releasing an external surface of the workpiece in process on the processing machine, and     a push rod operatively associated with the EXS to controllably command gripping and release of the external surface of the workpiece in process. The ISM is characterized in that:     the ISM comprises a bushing defining a bushing outside and a bushing inside, the bushing outside being configured to be retrievably received in axial alignment inside the inner chamber, and the bushing inside being configured for receiving the coupling mechanism, and     the ISM is configured for insertion and retention in the inner chamber to provide reversible exchange in replacement of the EXS, for operative association with the push rod to activate the coupling mechanism, and for retrieval from the inner chamber,     whereby retrieval of the EXS from the inner chamber and insertion therein of the IMS in replacement, provides operation of the processing machine in a first configuration with an EXS, and in a second configuration with an ISM, and vice versa. The ISM and the EXS are mutually and reversibly exchangeable in situ.        
 
         [0036]     The ISM is operable with a processing machine operating a process selected, alone and in combination, from the group of processes consisting of material removal, fastening, joining, surface treatment, and quality assurance. Furthermore, the ISM is configured for operation both when rotative and when non-rotative, thus with a processing machine comprising a rotating spindle.  
         [0037]     The processing machine defines an initial external configuration when operating an EXS, and the ISM is further characterized in that exchange of the EXS with the ISM maintains unaltered the initial external configuration of the processing machine.  
         [0038]     It is but another object of the present invention to provide an ISM and a method for implementing an ISM comprising a coupling mechanism activable for gripping and for release of a workpiece in process on a processing machine, the workpiece defining an external surface and an internal surface configured for access from the outside, the processing machine comprising: 
        an inner chamber defining an axis and a volume of space inside the processing machine,     an external surface chucking mechanism (EXS) releasably and retrievably retained in axial alignment in the inner chamber and configured for gripping and for releasing the external surface of the workpiece in process on the processing machine, and     a push rod operatively associated with the EXS to controllably command gripping and release of the external surface of the workpiece in process. The ISM is characterized in that:     the ISM comprises at least one fluid flow inlet coupled in fluid flow communication to at least one exit bore for fluid flow outlet, the former receiving a flow of fluid under pressure from at least one source of fluid and the latter discharging a controlled stream of fluid flow, and     the at least one exit bore is oriented and located respectively, toward and adjacent the workpiece, for aiming discharge of the controlled stream of fluid to impinge on and to eject the workpiece from the ISM when the coupling mechanism is activated to release the workpiece, whereby the ISM is configured for controlled ejection of the workpiece.        
 
         [0044]     The controlled stream of fluid acts on either one and on both the ISM and the workpiece by performing a function selected alone and in combination form the group of functions consisting of cooling and of lubricating, where the fluid is defined as an oil, and the oil is selected alone and in combination from the group of oils consisting of cooling oils and lubrication oils.  
         [0045]     The ISM defines an inside and an outside, and the controlled stream of fluid flow is discharged from the inside of the ISM to the outside. The ISM further comprises slits providing passage for fluid flow communication from the inside of the ISM to the outside, and 
        the controlled stream of fluid is discharged from the inside of the ISM via the at least one exit bore and via the slits comprised in the ISM, whereby ingression of matter from the outside to the inside of the ISM is prevented.       
 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0047]     In order to better understand and more fully appreciate the invention and to see how the same may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawing in which:  
         [0048]      FIG. 1  is a cross-section of a portion of a prior art spindle assembly, showing an external surface chucking mechanism EXS,  
         [0049]      FIG. 2  is a detail of the spindle seen in  FIG. 1 , where the supporting spindle assembly is deleted,  
         [0050]      FIG. 3  shows a cross-section of an internal surface chucking mechanism ISM mounted in the spindle as shown in  FIG. 2 , according to a first embodiment  100 ,  
         [0051]      FIG. 4  illustrates a partial cross-section showing details of a bushing, as seen in  FIG. 3 ,  
         [0052]      FIG. 5  is a partial cross-section exhibiting details of a collet appearing in  FIG. 3 ,  
         [0053]      FIG. 6  is a plan view with details of a plunger shown in  FIG. 3 ,  
         [0054]      FIG. 7  is a cross-section of a second embodiment  300  of the ISM,  
         [0055]      FIG. 8  depicts a detail of a plunger base according to  FIG. 7 ,  
         [0056]      FIG. 9  is an opening cone being part of the plunger base of  FIG. 7 , and  
         [0057]      FIG. 10  shows an oil collet, according to the second embodiment  300  of the IMS. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0058]     FIGS.  3  to  6  refer to a first embodiment  100  of the IMS.  FIG. 3  shows the same axially aligned spindle  3 , push rod  7 , and cap-nut  5  as seen in  FIG. 2 , where similar numbers and references indicate corresponding elements in the various Figs. Inside the inner chamber  70  defined as the volume delimited by the inside of the front portion  9  of the spindle  3 , frontward of the front facing arresting step  13 , and by the cap-nut  5 , the EXS has been replaced by the first preferred embodiment  100  of the ISM, referred to as ISM 100 . The ISM 100  is made of a bushing  101 , a plunger  103 , a spring  105 , and a collet- 107 , all axially aligned with the spindle  3 , along the axis A. The bushing  101  serves as a housing for interfacing the coupling mechanism, which is defined as being composed of the plunger  103 , the spring  105  and the collet  107 , with the spindle  3 . The bushing outside is supported by the spindle  3  and the bushing inside houses the coupling mechanism.  
         [0059]     With processing machinery such as lathes, the ISM rotates and some components thereof translate relatively to the spindle  3 . Coupling for rotation is achieved either by friction or by help of coupling means, while translation requires grooves and engaging means. Nevertheless, keys or pins, and corresponding grooves and bores for providing common rotation and relative translation are not shown in the Figs. and are not described, since these techniques are well known to the art.  
         [0060]     To keep the description simple, only the functional properties and details of the machine parts referred to are presented, while relieves, rounded-off corners, chamfers and the like, are deleted.  
         [0061]     Referring to  FIG. 4 , the axi-symmetric hollow bushing  101 , which rotates together with the spindle  3 , has a front portion with a bushing head  111 , and a back portion with a bushing body  113 . On the outside, the bushing body  113  and the bushing head  111  each have a cylindrical surface with uniform outer diameter. The outer diameter  115  of the bushing body  113  being smaller than the outside diameter  117  of the bushing head  111 , a back facing radially extending annular spindle shoulder  119  is created, perpendicular to the longitudinal axis A, for abutment with the front extremity  9 F of the spindle  3 . In the description below, all shoulders and flanges extend radially and are annular and perpendicular to the longitudinal axis A.  
         [0062]     The outside diameter  117  of the bushing head is dimensioned to fit inside the inner diameter restriction  6  in the cap-nut  5 . To the front of the bushing head  111 , a small front co-axial cylindrical protrusion  121  dimensioned to accommodate the bore  17  of the cap-nut  5 , creates a front facing bushing cap-nut shoulder  123 , which rests on the inside of the bottom  19  of the cap-nut  5 .  
         [0063]     When the bushing body  113 , which is accommodated to be received by the front portion  9 , is inserted into the front portion  9  of the spindle  3 , the bushing head  111 , resting on the spindle shoulder  119 , remains outside of the spindle, but the bushing body  113  resides inside the front portion  9  of the spindle  3 . Fastening the cap-nut  5  on the outside front threaded portion  9 ST of the spindle  3  clamps the spindle shoulder  119  against the front extremity  9 F of the spindle, and the cap-nut bottom  19  against the bushing cap-nut shoulder  123  to prevent axial translation of the bushing  101  relative to the spindle  3 . The bushing  101  is thus only an additional interface for receiving and supporting the plunger  103 , the spring  105 , and the collet  107 , inside the spindle  3 .  
         [0064]     The inner diameter  125  of the bushing body  113  being larger than the inside diameter  127  of the inner surface  124 , in the bushing head  111 , a back facing bushing collet shoulder  129  is created. The bushing  101  is terminated by a bushing rear  131  formed as a ring as wide as the difference between the bushing body outer diameter  115  and the bushing body inner diameter  125 .  
         [0065]     With reference to  FIG. 5 , the collet  107 , which is an internal surface gripping collet, is hollow and features a substantially frusto-conical collet front portion  141 , a cylindrical collet body  143 , and a collet flange  145 . The collet  107  rotates together with the bushing  101 .  
         [0066]     On the outside, the collet body  143  has a cylindrical outer surface  147  with a constant outer diameter  149  starting at the back of the collet front portion  141  up to the collet flange  145 . On the inside, the collet body  143  has a cylindrical inner surface  151  with a constant inner diameter  153 .  
         [0067]     The collet flange  145 , which delimits the back extremity of the collet body  143 , extends radially outward to an outer diameter  155 , to form a front facing collet-bushing shoulder  157  and a back facing collet rest  159  with a collet opening  160 .  
         [0068]     The outside profile of the collet front portion  141  is shaped to provide, from the front to the back and with reference to the axis A, a perpendicular front extremity  161 , a coaxial cylindrical grip surface  163 , a perpendicular front facing indexing shoulder  165 , and an external frusto-conical surface  167  separated from the indexing shoulder  165  by a short coaxial cylindrical portion  169 . The frusto-conical surface  167  continues to the back to connect with the front of the collet body outer diameter  149 . It is noted that the low front facing index shoulder  165  is high enough to register a workpiece W in abutment therewith, for axial reference purposes.  
         [0069]     The perpendicular front extremity  161  is pierced by a coaxial cylindrical passage  171  with an internal diameter  173  connecting to an inside conical taper  175  opening-up backward and substantially conforming with the external frusto-conical surface  167 , via an intermediate conical section  177 . In turn, the inside conical taper  175  blends with the inner diameter  153  of the collet body.  
         [0070]     The collet front portion  141  is cut radially by a plurality of slits  178 , e.g. three separate equally radially distributed slits  178 , running from the axis A outward. Axially, the slits  178  are cut lengthwise in the front extremity  161  of the collet  107 , up to the front of the collet body  143 , to terminate in a slit end  179 , thereby forming three collet fingers  181  cantilevered to the collet body  143  and configured to flex radially outward when urged by an internal force appropriately applied from within the collet  107 . It is understood that the minimal number of slits is two radial slits  178 , or one diametrical slit. Although this example presents three slits  178 , only practical considerations limit the number of slits.  
         [0071]     The slits  178  divide the cylindrical internal grip surface  163  into separate radially outward facing jaw pads  183 , residing in a normally retracted position. When forced to open, thus to extend radially outward, the jaw pads  183  are configured to grip an inner diameter designated as id in  FIG. 3 , of a workpiece W to be processed. When the force to open is removed, the jaw pads  183  retract radially inward, to their normally retracted position, whereby the gripped workpiece W is released.  
         [0072]     With reference to  FIG. 3 , the collet  107  resides within the bushing  101 . The outer surface  147  of the collet body  143  is received along its entire length by the bushing head  111  inner surface  124 . The collet flange outer diameter  155  engages into the inner diameter  125  of the bushing back portion  113  in sliding fit. Likewise, the front facing collet-bushing shoulder  157  of the flange  145  abuts the bushing collet shoulder  129  of the bushing  101  under the pressure of the spring  105 , which biases the back facing rest  159  of the collet flange  145 . At the front, the jaw pads  183  protrude out of the cap-nut  5 , through the cap-nut bore  17 . It is noted that the grip surface  163  may be shaped to match the internal shape of the workpiece W to be chucked. The grip surface  163  may thus be cylindrical or polygonal, as required to hold the workpiece.  
         [0073]     With reference to  FIG. 3 , the axi-symmetric plunger  103  is the element that transmits motion and force originating from the push rod  7  for the actuation of the ISM. The push rod  7  drives the plunger  103  to actuate the opening and the closing of the collet fingers  181  of the collet  107 , and thereby, respectively, grip and release the inner diameter id of a workpiece W. Gripping is considered as gripping and maintaining grip of the workpiece W for as long as commanded.  
         [0074]     With reference to  FIG. 6 , the plunger  103  is coaxially axi-symmetric and has a slender plunger rod  201  aligned with and attached in perpendicular to the front face  203  of a plunger body  205 , which is terminated by a plunger flange  207  affixed to the back of the plunger body.  
         [0075]     The plunger body  205  is configured as a solid cylinder with an outside surface  209  of uniform outside diameter  211 , and if so wished, the outside surface  209  may include relieves to form support rings. If further desired, the plunger body  205  may be hollowed out, as well as the plunger  103 .  
         [0076]     The plunger flange  207 , with an outside diameter  213 , extends radially outward of the plunger body  205  to form a plunger flange front  215  and a plunger flange back  217 .  
         [0077]     The plunger rod  201  features a slender cylindrical plunger extender  219  with an outer diameter  221 , terminated to the front by a frusto-conical rod head  223  with a plunger front extremity  225 , either with a rounded-off tip or terminated by any other type and shape of tip. The rod head  223  conforms to the inside of the intermediate conical section  177  of the collet  107 .  
         [0078]     As seen in  FIG. 3 , the outside surface  209  of the plunger body  205  is received in sliding support by the inner diameter  125  of the bushing body  113 , which is larger than the outside diameter  211  of the plunger body  205 . The plunger flange  207 , with an outer diameter  213  larger than the inner diameter  125  but smaller than the outer diameter  115  of the bushing body  113 , resides to the back of the bushing rear  131  but to the front of the front facing arresting step  13  of the spindle  3 . Furthermore, the plunger flange back  217  is accommodated to abut against the front face  7 F of the push rod  7 .  
         [0079]     To the front of the plunger extender  219 , the rod head  223  conforms and abuts with the intermediate conical section  177  of the collet front portion  141 , while the outer diameter  221  of the plunger extender  219 , is concentrically aligned inside the larger inside diameter  153  of the collet body  143 . Moreover, the back end  105 B of the spring  105  biases the front face  203  of the plunger body  205 .  
         [0080]     When assembled inside the front portion  9  of the spindle  3 , the collet  107  is received inside the bushing  101  with the collet flange  145  abutting the bushing collet shoulder  129  and with the collet front extremity  161  protruding frontward and out of the opening bore  17  of the cap-nut  5 .  
         [0081]     The plunger body  205  of the plunger  103  is supported by the inner surface  122  of the bushing body  113 , and permits sliding axial translation. The plunger flange  207 , which is configured to translate inside the back of the front portion  9  of the spindle  3 , is adapted for contact with the open front face  7 F of the push rod  7 , so that when the push rod  7  extends forwards, that front face  7 F pushes the plunger  201  forward. Frontward travel of the plunger flange  207  is limited by the bushing rear  131 , while backward translation is stopped by the front facing arresting step  13  in the inside  3 IN spindle  3 .  
         [0082]     The spring  105  is internal to the bushing body  113  and permits the undisturbed translation of the plunger extender  219  through the spring inside  105 IN. The front-end  105 F of the spring  105  biases the collet flange  145  and the back end  105 B of that spring rests on the front facing collet-bushing shoulder  157  of the collet  107 . It is noted that the denomination spring  105  refers to one or more resilient elements biasing the collet  107  away from the plunger body  205 .  
         [0083]     The rod head  223 , which abuts the intermediate conical section  177  on the inside of the collet front portion  141 , is operated by the frontward translation of the push rod  7  to open the collet fingers  181  for gripping a workpiece W, and when the push rod retreats, it is the spring  105  that pushes the plunger  103  backwards, whereby the collet fingers  181  close to release the workpiece W. The workpiece remains gripped as long as the push rod  7  is extended.  
         [0084]     The axial force delivered by the push rod  7  is decomposed in an axial force and into a perpendicular radial outward force applied for opening the jaws  181 . Therefore, the more the rod head  223  translates forward, the more the jaw pads  183  are urged in outward radial separation, and the better and with more force the inner surface of a workpiece W is gripped.  
         [0085]     It is noted that the closer the intermediate conical section  177  is to the collet front extremity  161 , and thus the more the rod head  223  penetrates frontward and closer to the outward facing jaw pads  183 , the less bending moment is imposed on the collet fingers  181 . The bending moments and the axial forces are lower the sharper the angle of the rod head  223  and of the mating intermediate conical section  177 .  
         [0086]     The forward translation of the push rod  7  is controlled to correctly operate the ISM, without excess translation that might cause damage. Excess forward travel or force applied by the push rod  7  will not damage the collet  107  since the force applied by the front face  7 F to the plunger flange  207  will be countered by the bushing rear  131 .  
         [0087]     For use of the ISM 100  on a processing machine, the push rod  7  is first withdrawn to the retracted position, backward enough to prevent transmission of force to the collet  107 . When force is not applied on the collet  107 , the jaws  181  are unextended. A workpiece W with an inside surface may now be placed on the outward facing jaws pads  183 . Next, the push rod face  7 F is translated forward to contact the plunger  103 , pushing the plunger flange  207  forward, thereby forcing the rod head  223  to engage the collet fingers  181 , which then open up and grip the inside surface of the workpiece W.  
         [0088]     In general, it is possible to manufacture an external surface in a workpiece W, if not already existing. The EXS, which grips the workpiece on an external surface, may be of use to machine the internal surface, even if necessary only for purposes of manufacturing. The internal surface is possibly made a priori.  
         [0089]     In manufacturing, the benefits of the simple reversible exchange of an EXS with an ISM 100  come to full exploitation. When an installed EXS has to be replaced by an ISM 100  in a spindle assembly  1 , the following steps are performed. It is assumed that an assembled ISM 100  is at hand, with the spring  105  mounted on the plunger extender  219 , both already inserted inside the collet body  143 , and residing inside the front portion  111  of the bushing  101 .  
         [0090]     a. With the spindle  3  stopped and the push rod  7  retreated to the back, the cap-nut  5  is unscrewed and removed from the spindle, thereby exposing the open front portion  9  of the spindle  3 .  
         [0091]     b. The EXS is retrieved by pulling the collet actuator  23  out of the open front portion  9  of spindle  3 .  
         [0092]     c. The ISM 100  is introduced into the open front face  9 F of the spindle  3 , with the plunger flange  207  being inserted first.  
         [0093]     d. The cap-nut  5  is seated over the bushing cap-nut shoulder  123 , in screw-threaded engagement with the external screwthread  9 ST, and secured in place.  
         [0094]     The procedure for the exchange of an ISM 100  with an EXS is essentially the same. This time, it is the ISM 100  that is retrieved from the open front portion  9  of the spindle  3  by pulling out the bushing  101 , and replaced by the EXS, with the back introduced first. Advantageously, the initial external configuration of the processing machine equipped with the EXS is not altered when in use with an ISM.  
         [0095]     In industry, a processing machine equipped with two spindles, independent or not, wherein each spindle operates an EXS, in mutual opposite axial alignment and translation, is also economically beneficial. In regular operation, a workpiece W, machined from stock material automatically fed as one piece into the processing machine, is first gripped by a first EXS mounted in a first spindle, and processed as required, on the surface not covered by the first EXS. Thereafter, a second EXS, in alignment with the first EXS, and mounted on the second spindle which operates as a counter spindle, grips the workpiece W for further processing. This further processing may simply only cut the workpiece W off the stock material, or feature additional processing operations. As was explained above, the gripping jaws possibly blemish the outer surface finish of the workpiece.  
         [0096]     In the above-mentioned case, it is advantageous to exploit the present invention and replace the EXS held in the second spindle, thus in the counter-spindle aligned with the EXS, with an ISM 100 . The processing machine then presents a first spindle with an EXS is alignment with a second spindle supporting an ISM 100 . When the EXS of the first spindle processes the workpiece W, an internal surface facing the counter spindle, is also machined, if not available a priori, for later gripping by the ISM 100 . Before completion of the processing of the workpiece W held by the EXS, the ISM 100  is brought to the same rotational speed as the EXS and is translated to approach and grip the workpiece W. It is now possible to continue processing of the workpiece W, which is gripped by both the EXS and the ISM.  
         [0097]     When processing related to the gripping with the EXS is completed, the workpiece W, already gripped by the ISM 100  is cut-off on the side of the EXS, thereby remaining gripped solely by the ISM 100  on the counter spindle. If desired, the workpiece W is indexed to abut the front facing indexing shoulder  165  for registration. With or without registration, the workpiece W is now ready for further processing.  
         [0098]     Registration is achieved by pushing the workpiece W held by the ISM 100  against a surface, releasing grip of the ISM 100  so that the applied pressure will translate the workpiece W in abutting contact with the indexing shoulder  165  and then, gripping the workpiece W with the ISM 100  again. As stated above, the operation of the push rod  7  opens and closes the grip of the ISM 100  on the internal surface of the workpiece W.  
         [0099]     For example, a profiled contour along the overall external length of the workpiece W may be machined, or marks left on the external outer surface of the workpiece W may be obliterated by additional processing when gripped by the ISM 100 . Simultaneously, processing of a next workpiece may commence on the first spindle with the EXS, even before completion of the present workpiece W on the counter spindle with the ISM 100 . Inherently, the ISM will not leave marks on the outside of the workpiece W.  
         [0100]     A production facility may possibly store not one ISM 100  tool but a family of such tools, where each one ISM 100  is specified by the inner surface size and shape able to be gripped by the collet  107 . Another approach is to store only a collection of collets  107 , for exchange and replacement within an ISM 100 . The collets  107 , out of the collet collection, are interchangeable and are chosen from a variety of standard or custom made collets. In process, a collet is selected according to the shape and size of the bore or the internal surface opened in the workpiece W.  
         [0101]     To replace a first collet  107  residing inside an ISM by a second other collet, it is necessary to slide the plunger  103  and the spring  105  out of the bushing  101  of the ISM 100  assembly. Then, the first collet  107  is slid out, or pushed to slide out of the bushing  101 . Next, the spring  105  is mounted around the plunger extender  219  on top of which the second other collet is slid concentrically. As a last step, the bushing  101  is assembled concentrically over the second other collet and the plunger  103  is introduced into the bushing whereby the ISM 100  is reassembled.  
         [0102]     A second preferred embodiment  300  of an internal surface chucking mechanism ISM 300  is described below with reference to FIGS.  7  to  10 . In general, the ISM  300  shown in  FIG. 7  is similar to the ISM 100  depicted in  FIG. 3 , but for the possibility to introduce fluid under pressure to the inside of the ISM 300 . The received fluid is released as a stream out of the front portion of the collet, opposite the retained workpiece, to eject the workpiece from the ISM 300  when the grip is released. The fluid, such as oil if desired, cools and lubricates the ISM 300  and the workpiece. Furthermore, the release of fluid prevents the ingress of matter from the outside into the inside of the ISM 300 .  
         [0103]     To facilitate the production of a plunger with an inside fluid conduit, the plunger  103  is possibly made of more than one part. In addition, the collet  107  is provided with oil outlets. As an alternative, a sleeve is inserted inside the spring  105 , to arrest the frontward translation of the push rod  7 . Similar numbers and references are used to indicate corresponding elements in the various Figs.  
         [0104]     The ISM 300  resides in the inner chamber  70  defined above, and is retained therein by the cap-nut  5  and the bushing  101 , as with the ISM 100 . Unlike the ISM 100  shown in  FIG. 3  with a single-piece plunger  103 , the plunger of the ISM 300  is segmented for ease of manufacturing, and built out of two or more parts coupled together, as desired.  
         [0105]     As above, the keys or pins and corresponding grooves and bores, possibly used for the coupling of jointly rotating parts and for relative translation displacement are not mentioned, for the sake of simplicity. Only functional features of the machine parts are depicted and described.  
         [0106]     With reference to  FIG. 7 , the segmented plunger  301  is a made, for example, of two separate sections coupled together, namely a plunger base  301  and a separate opening cone  303 , resembling the rod head  211  of the ISM 100 .  
         [0107]     In  FIG. 8 , the plunger base  301  is shown with a front plunger pipe  305 , and a plunger main body  307 , both connected on the inside by an axial bore  309  of constant or variable inner diameter, accommodated for the passage of fluid. The axial bore  309  extends from a flange inlet  311  opened in a hollow flange  313  at the back of the plunger main body  307 . The plunger pipe  305  is coupled to a front face  314 , to the front of the plunger main body  307 . The axial bore  309  ends in a plunger pipe outlet  315  open at the front extremity  317  of the plunger pipe  305 . A recessed external cylindrical surface  319 , at the front extremity  317  of the plunger pipe  305 , carries a external screwthread  321 , but is only an example of a coupling means to the opening cone  303 , out of the many possible coupling connections known to the art.  
         [0108]     Once the plunger base  301  is coupled together in assembly with the opening cone  303 , the geometry and dimensions of the assembly are the same as those of the plunger  103 . However, if desired, the plunger base plunger  301  may itself be implemented as two or more parts coupled together. For example, by producing separately the plunger pipe  305  and the plunger main body  307 , and then coupling both together by conventional means.  
         [0109]     The flange inlet  311  is accommodated to receive fluid, such as oil, from a source not shown in the Figs. That fluid is then discharged via the pipe outlet  315 . Oil is possibly supplied from the processing machine itself of from an external source.  
         [0110]      FIG. 9  is an illustration of the hollow opening cone  303 , configured for passage of fluid therethrough and for attachment to the plunger pipe outlet  315 . If desired, the attachment is releasable, to permit exchange and replacement of the opening cone  303 . Means for coupling and for releasing of the hollow opening cone  303  and of the plunger pipe outlet  315 , such as facets, are not shown.  
         [0111]     At the back of the hollow opening cone  303 , a cone rear inlet  331  leads to a hollow inside  333  formed by a leading bore  335  and a trailing bore  337 . An internal screw thread  339 , accommodated at the rear inside of the trailing bore  337 , permits coupling of the hollow opening cone  303  with the external screwthread  321  located at the front extremity  317  of the plunger pipe  305 . Coupling of the hollow opening cone  303  to the plunger pipe outlet  315  is possibly achieved by other means, all well known to the art.  
         [0112]     On the external frusto-conical surface  341  of the hollow opening cone  303  there is provided at least one radial flow bore  343 , entered for radial fluid flow communication with the leading bore  335 . When the hollow opening cone  303  is coupled to the plunger pipe  305 , fluid flow communication is established from the flange inlet  311  of the plunger base  301  via the axial bore  309  and the hollow inside of the hollow opening cone  303 , to the radial flow bore  343 , and from there, to the external frusto-conical outside and thus to the opening cone outside  345 .  
         [0113]      FIG. 10  is an oil collet  351 , alike the collet  107  of embodiment ISM 100 , but for fluid outlet passage openings at the front. One or more axial fluid outlet passages  353  are bored into the external frusto-conical surface  167  of the oil collet  351 . For example, three axial fluid outlet passages  353 , of which only two, designated as  353   a  and  353   b  are seen in  FIG. 10 , are distributed each at a different parallel distance from the axis A of the oil collet  351 , opening a fluid passage from the oil collet inside  355  to the external frusto-conical surface  167  and to the outside  357 . Fluid, such as oil, is thus able to flow out of the oil collet inside  355  and from there to the oil collet outside  357  via the slits  178 , and the at least one axial fluid outlet passage  353 . If the opening cone  303  is configured therefor, such as by piercing an axial bore therein, oil may even exit via the axial cylindrical passage  171 .  
         [0114]     The ISM 300  is seen assembled in  FIG. 7 , with the hollow plunger base  301  coupled to the opening cone  303 , which resides inside the oil collet  331 . As described above, fluid flow communication is established from the flange inlet  311  to the axial fluid outlet passage(s)  353 , and thus to the front of the cap-nut  5 .  
         [0115]     The fluid is delivered to the oil collet  351  under controlled command, either automatic or manual and selectable to operate, constantly or during chosen periods, either continuously or intermittently, according to the processing activity of the processing machine operating the ISM 300 . If preferred, the fluid is a liquid and if desired, the liquid is oil, for cooling and for lubrication.  
         [0116]     When a fluid, such as oil for example, is introduce to the inside  355  of the oil collet  351 , that oil will serve to lubricate the external frusto-conical surface  341  of the opening cone  303 , the intermediate conical section  177  of the oil collet  351 , and the components of the ISM  300 . The oil will also cool the ISM  300 . The exact location and orientation of the fluid communication passages is not crucial, as long as the oil flows over the intermediate conical section  177  and the external frusto-conical surface  341 .  
         [0117]     The axial fluid outlet passages  353  bored axially in the external frusto-conical surface of the oil collet  351  serve as outlets for continuous or intermittent jets or streams of oil directed upon command, to eject the workpiece W from the collet fingers  181 , when the outward facing jaw pads  183  are released. These same oil jets do also cool the workpiece W.  
         [0118]     Furthermore, the oil exiting out of the inside  355  to the oil collet outside  357 , from via the slits  178 , and the at least one axial fluid outlet passage  353  prevent the ingression of matter, such as particles, dirt, and contaminants, to the inside of the oil collet  351  and of the ISM 300 . Such particles may be substance removed from the workpiece W during process, such as chips of material, cutting tool or grinding tool particles, and the like.  
         [0119]     The spring  105  is possibly configured as a compression spring made from circular, rectangular or other coil cross-section, either as a single spring or as a plurality of concentric springs.  
         [0120]     A stop sleeve  361 , which is but a cylindrical hollow bushing with uniform outside and inside diameter, may be inserted inside the spring  105  and over the plunger pipe  305 , as seen in  FIG. 7 , to constrain the forward motion of the push rod  7 . A first end of the stop sleeve  361  rests against the collet rest  159  while the plunger flange front  215  of the plunger base  301  supports a second end of the stop sleeve  361 . This last arrangement may replace the arrest of the push rod  7  on the bushing  101  by intermediary of the plunger flange  207 , as an alternative for the configuration described above for the ISM 100 . The length of the stop sleeve  361  is adjustable to suit requirements. The stop sleeve  361  is replaceable and exchangeable.  
         [0121]     Still with reference to  FIG. 7 , the ISM 300  is shown assembled in operative condition. When compared to the ISM  100 , the ISM 300  permits replacement and exchange of the opening cone  303 , of the oil collet  331 , and of the stop sleeve  361 . Both the opening cone  303 , and the oil collet  331 , which suffers wear and tear, are made to resist heavy duty operation by producing them for harsh service, from resistant materials, duly heat and surface treated with appropriate processing and finish.  
         [0122]     In comparison with the ISM 100 , the ISM 300  is configured to perform as an ISM 100 , while providing the advantages described above and related to the fluid conduits and to the flow of fluid. As stated before, the ISM is not limited to rotative processing machinery but operates also with non-rotative equipment. The process wherewith the ISM is operable are not limited to spindles for removing chips of material, such as with lathes. The ISM operates as well with machines for fastening, for joining, for surface treatment for quality assurance, and with other equipment.  
         [0123]     It will be appreciated by persons skilled in the art, that the present invention is not limited to what has been particularly shown and described hereinabove. For example, the mechanism of the ISM may be modified and the conduit of fluid altered. Furthermore, the processing of a workpiece is not limited only to a first processing step when gripped by an EXS and to a second processing step when gripped by an ISM. In addition, more than just one EXS and one ISM may be used for processing a workpiece. Rather, the scope of the present invention is defined by the appended claims and includes both combinations and sub-combinations of the various features described hereinabove as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description.