Patent Publication Number: US-6220671-B1

Title: Cutting tool holder retention system

Description:
TECHNICAL FIELD 
     This invention relates to excavation cutting tools, and more particularly a cutting tool holder retention system for retaining a cutting tool holder within a support block during use. 
     BACKGROUND ART 
     Excavation cutting tool assemblies for such applications as continuous mining or road milling typically comprise a cutting tool, sometimes referred to as a cutting bit, rotatably mounted within a cutting tool holder, sometimes referred to as a cutting tool sleeve, bit holder, or bit sleeve. In such assemblies, the cutting tool holder is mounted within a support block. The support block in turn is mounted onto a drum or other body, typically by welding, which in turn is driven by a suitable power means. When a number of such support blocks carrying cutting tool holders and cutting tools are mounted onto a drum or other body, and the drum or other body is driven, the cutting tools will engage and break up the material which is sought to be mined or removed. The general operation of such mining, road milling, or other such machines is well known in the art. 
     As mentioned, the cutting tool holder may be mounted within the support block, typically via some mechanical connection. For example, U.S. Pat. No. 5,322,351 to Lent (referred to as the Lent patent) discloses a cutting tool holder  42  mounted within a tool holder receiving pocket  28  of a support block, referred to in the Lent patent as a segment member  18 , via a wedge member  46 . The wedge member  46  is movably connected to the support block via an adjustable screw member  54 . To use the apparatus disclosed in the Lent patent, a cutting tool holder  42  is disposed in the tool holder receiving pocket  28  such that the base portion of the tool holder mates with, and is located under, an inclined wall surface  24  within the receiving pocket  28 . The wedge member  46  is then moved by tightening the adjustable screw member  54  such that the cutting tool holder  42  is held in place by the wedge member  46  and the inclined wall surface  24  of the receiving pocket  28  within the receiving pocket  28  of the support block. 
     As another example, U.S. Pat. No. 5,378,050 to Kammerer and Diessner (referred to as the Kammerer patent) discloses a chisel holder  30  having a neck  31  which may be inserted into a plug-in receptacle  21  of a support block, referred to as a basic part  20  in the Kammerer patent. The plug-in neck  31  has a recess  37  which defines a pressure surface  38 . The pressure surface  38  faces a pressure screw  50  adjustably disposed in the support block, the basic part  20 , so as to intersect the plug-in receptacle  21 . The pressure screw  50  may be adjusted such that the pressure screw  50  protrudes into the recess  37  of the neck  31  of the chisel holder  30  and such that a retracting force is exerted on the pressure surface  38  of the chisel holder  30 . 
     As yet another example, U.S. Pat. No. 4,057,294 to Kreckler (referred to as the Kreckler patent) discloses a removable member  52 , into which the shank of a cutter bit  52   c  may be mounted, mounted within a dove-tailed slot  51  of a base member  50  via a wedge element  53 . The wedge element  53  is movably connected to the removable member  52  via a bolt  54 . To use the apparatus disclosed in FIGS. 1-3 of the Kreckler patent, the removable member  52  is disposed in the dove-tailed slot  51  such that an inclined portion  52   a  of the removable member  52  is in contact with, and located under, an inclined portion  50   a  of the base member  50 . The wedge element  53  is then moved by tightening the bolt  54  such that the removable member  52  is held in place by the wedge element  53  and the inclined portion  50   a  within the dove-tailed slot  51  of the base member  50 . 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved cutting tool holder retention system which allows a cutting tool holder to be assembled with a support block. 
     In carrying out the above object, and other objects and features of the present invention, an improved cutting tool holder retention system is provided. The improved cutting tool holder retention system comprises a support block and a tool holder. The support block has a tool holder bore and the tool holder has an effective shank, the effective shank being expandably adjustable within the tool holder bore so as to retain the effective shank within the tool holder bore. The effective shank may be retained within the tool holder bore by way of frictional engagement. 
     In a more specific embodiment, the effective shank is defined by a holder shank and a retainer portion, the retainer portion being adjustably connected to the holder shank such that the effective shank is expandable within the tool holder bore so as to retain the effective shank within the tool holder bore. In such case, the effective shank may be retained within the tool holder bore by way of frictional engagement. 
     In a preferred embodiment, the holder shank has a shank wedge surface and the retainer portion has a retainer wedge surface, the retainer portion being adjustably connected to the holder shank such that the retainer wedge surface engages the shank wedge surface so as to expand the effective shank. In such case, the tool holder bore may have a bore interior surface and the retainer portion may have a retainer engagement surface, the retainer engagement surface and holder shank defining an effective shank dimension which is expandable within the tool holder bore so as to retain the effective shank within the tool holder bore. Additionally, in such case the tool holder may have a holder bore, the holder bore intersecting at least a portion of the holder shank, and the retainer portion may have a retainer pin bore, at least one of the holder bore and retainer pin bore being threaded. Such embodiment would further include a pin having a pin threaded portion. The pin would run through the holder bore and retainer pin bore and the pin threaded portion would threadably engage the at least one of the holder bore and retainer pin bore so as to adjustably connect the retainer portion and holder shank such that by rotation of the pin the retainer portion is movable relative to the holder shank. 
     In an alternative embodiment, the excavation cutting tool holder retention system includes a support block, a tool holder, and a retainer. The support block has a tool holder bore. The tool holder has a holder shank, the holder shank having a shank axis and a shank wedge surface, the shank wedge surface being inclined relative to the shank axis. The retainer has a retainer wedge surface and a retainer engagement surface. The retainer is adjustably connected to the tool holder such that the retainer wedge surface slidingly engages the shank wedge surface and such that the retainer engagement surface and the holder shank cooperate to retain the holder shank within the tool holder bore. The retainer engagement surface and the holder shank may cooperate to retain the holder shank within the tool holder bore by way of frictional engagement with the tool holder bore. 
     In a preferred embodiment, the retainer is adjustably connected to the tool holder by way of a pin. In such case, the tool holder may have a tool holder bore, the holder bore intersecting at least a portion of the holder shank, and the retainer may have a retainer pin bore, at least one of the holder bore and the retainer pin bore being threaded. The pin may have a pin threaded portion which threadably engages the at least one of the holder bore and retainer pin bore such that by rotation of the pin the retainer is movable relative to the holder shank as the retainer wedge surface slidingly engages the shank wedge surface. 
     In yet another preferred embodiment, the pin has a pin diameter and the holder bore has a holder bore diameter, the holder bore diameter being greater than the pin diameter such that the pin may move laterally within the holder bore to allow the retainer to move relative to the holder shank. 
     In yet another preferred embodiment, the shank wedge surface may have a first shank wedge surface portion located on one side of the holder bore and a second shank wedge surface located on the other side of the holder bore. In such case, the retainer wedge surface may have a first retainer wedge surface portion located on one side of the retainer pin bore and a second retainer wedge surface portion located on the other side of the retainer pin bore such that the first and second retainer wedge surface portions slidingly engage the first and second shank wedge surface portions respectively and such that the retainer engagement surface and the holder shank cooperate to retain the holder shank within the tool holder bore. 
     In yet another preferred embodiment, the other one of the holder pin bore and retainer pin bore may have a pin bore shoulder, and the pin may have a pin head which engages the pin bore shoulder. 
     In another alternative embodiment, the excavation cutting tool holder retention system includes a support block, a tool holder, a retainer, and a pin. The support block has a tool holder bore. The tool holder has a holder shank and a holder bore, the holder bore intersecting at least a portion of the holder shank. The pin runs through the holder bore and adjustably connects the retainer to the holder shank such that the retainer is movable relative to the holder shank and such that the holder shank and retainer cooperate to retain the holder shank within the tool holder bore. In such case, the holder shank and retainer may cooperate to retain the holder shank within the tool holder bore by way of frictional engagement with the tool holder bore. 
     In a preferred embodiment, the holder shank has a shank wedge surface and the retainer has a retainer wedge surface which slidingly engages the shank wedge surface such that the retainer is movable relative to the holder shank. In such case, it is preferred that the holder shank have a shank axis and that the shank wedge surface be inclined relative to the shank axis. 
     In an alternative embodiment, the shank wedge surface is a first shank wedge surface portion on one side of the holder bore and a second shank wedge surface portion on the other side of the holder bore. 
     In another preferred embodiment, the retainer has a threaded retainer pin bore and the pin has a pin head which engages the holder bore and a pin threaded portion which threadably engages the retainer pin bore. Accordingly, the pin head may be rotated to draw the holder shank and retainer toward each other and such that the retainer wedge surface slidingly engages the shank wedge surface so as to move the retainer relative to the holder shank. 
     In another preferred embodiment, the shank wedge surface may have a first shank wedge surface portion on one side of the holder bore and a second shank wedge surface portion on the other side of the holder bore. The retainer pin bore may likewise have a first retainer wedge surface portion located on one side of the retainer pin bore and a second retainer wedge surface portion located on the other side of the retainer pin bore such that the first and second retainer wedge surface portions slidingly engage the first and second shank wedge surface portions respectively and such that the retainer and holder shank cooperate to retain the holder shank within the tool holder bore. 
     In a preferred embodiment, the pin has a pin diameter and the holder pin bore has a holder pin bore diameter greater than the pin diameter to facilitate lateral movement of the retainer relative to the holder shank. 
     In yet another alternative embodiment, the excavation cutting tool holder retention system includes a support block, a tool holder, and a retainer. The support block has a tool holder bore, the tool holder bore having a bore interior surface. The tool holder has a holder shank. The retainer has a retainer compressible surface, the retainer being adjustably connected to the tool holder such that the retainer compressible surface is compressed against the bore interior surface so as to retain the holder shank within the tool holder bore. 
     In a preferred embodiment, the tool holder bore has a bore recess and at least a portion of the compressible surface of the retainer protrudes into the bore recess when the retainer compressible surface is compressed. 
     In another preferred embodiment, the holder shank and the retainer compressible surface define a shank effective dimension which is adjustably expandable within the tool holder bore and such that the retainer compressible surface is compressed against bore interior surface so as to retain the holder shank within the tool holder bore. In such case, it is preferable that the tool holder bore has a bore recess and at least a portion of the compressible surface of the retainer protrudes into the bore recess when the retainer compressible surface is compressed. 
     In fact, in all of these embodiments, at least a portion of the retainer of the retainer engagement surface may be a retainer compressible surface such that the retainer compressible surface is compressed against the bore interior surface so as to retain the effective shank or holder shank within the tool holder bore. In such case, it is preferable that the tool holder bore has a bore recess and the at least a portion of the compressible surface of the retainer engagement surface protrudes into the bore recess when the retainer compressible surface is compressed. 
     The present invention also includes an improved retainer portion of an effective shank for use with a support block, a tool holder, and a pin, the support block having a tool holder bore, the tool holder bore having a bore interior surface, the tool holder having a holder shank, the holder shank having a shank axis and a shank wedge surface, the shank wedge surface being inclined relative to the shank axis, the tool holder also having a holder bore intersecting at least a portion of the holder shank, the pin having a pin head which engages the tool holder and a pin threaded end. The improved retainer portion of the effective shank comprises a retainer having a retainer wedge surface, a retainer engagement surface, and a threaded retainer pin bore. The threaded retainer pin bore threadably engages the pin threaded end such that rotation of the pin will cause the retainer wedge surface to slidably engage the shank wedge surface and such that the retainer engagement surface and the holder shank cooperate to retain the holder shank within the tool holder bore. 
     In a preferred embodiment, the retainer wedge surface has a first retainer wedge surface portion located on one side of the retainer pin bore and a second retainer wedge surface portion located on the other side of the retainer pin bore. 
     The present invention also includes an improved tool holder for use with a support block, a retainer, and a pin, the support block having a tool holder bore, the tool holder bore having a bore interior surface, the retainer having a retainer wedge surface and a retainer engagement surface, the pin having a pin head and a pin diameter. The improved tool holder comprises an outer wear region and a holder shank. The holder shank has a shank axis and a shank wedge surface. The shank wedge surface is inclined relative to the shank axis. The tool holder also has a holder pin bore intersecting at least a portion of the holder shank and receiving the pin which is adjustably connected to the retainer such that the retainer wedge surface slidingly engages the shank wedge surface and such that the retainer engagement surface and the holder shank cooperate to retain the holder shank within the tool holder bore. 
     In a preferred embodiment, the shank wedge surface has a first shank wedge surface portion located on one side of the holder pin bore and second shank wedge surface portion located on the other side of the holder pin bore. 
     In another preferred embodiment, the holder pin bore has a holder pin bore diameter greater than the pin diameter to facilitate lateral movement of the retainer relative to the holder shank. 
     The advantages resulting from this invention are numerous. For example, the components are relative simple to manufacture and use. 
     Another advantage is the relative simplicity of relying on an expandable effective shank to retain the holder shank within the tool holder bore of the support block. 
     Yet another advantage is that relatively large retention forces may be generated by the sliding engagement between the retainer wedge surface and the shank wedge surface. 
     In embodiments where the retainer has a retainer compressible surface, another advantage is that the retainer compressible surface is compressed against the bore interior surface so as to accentuate retention. This effect is increased in embodiments where the tool holder bore includes a bore recess such that the retainer compressible surface is compressed so as to protrude into the bore recess. 
     In embodiments where the retainer wedge surface consists of a first retainer wedge surface portion and a second retainer wedge surface portion bisected by the retainer pin bore, the resulting double seat arrangement also provides the advantage of minimizing bending forces on the pin. 
     Further objects and advantages of this invention will be apparent from the following description, reference being had to the accompanying drawings in which one embodiment of the present invention is shown. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     While an embodiment of the invention is illustrated, the particular embodiment shown should not be construed to limit the claims. It is anticipated that various changes and modifications may be made, and that various embodiments may be employed, without departing from the scope of this patent. 
     FIG. 1 is a side view of a cutting tool holder assembled with a support block showing one embodiment of the invention; 
     FIG. 2 is a side view identical to FIG. 1, except that the support block and the cutting tool holder shank are shown in cross-section, showing the components in a loosened condition; and 
     FIG. 3 is a side view identical to FIG. 2 except that the components are in a tightened condition. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     One embodiment of the cutting tool holder retention system  10  is shown in FIGS. 1-3. The cutting tool holder retention system  10  includes a support block  12  having a tool holder bore  14 . The cutting tool holder retention system  10  also includes a cutting tool holder  18  having a holder shank  20  joined to an outer wear portion  22 . The cutting tool holder retention system  10  further includes a retainer  24 . In the embodiment shown, a pin  26  is used to adjustably connect the retainer  24  to the holder shank  20  of the cutting tool holder  18 . As indicated in the embodiment shown, a cutting tool  28  may be rotatably and releasably mounted within the cutting tool holder  18 . However, the scope of this patent covers cutting tool holder retention systems in which the cutting tool is mounted to the cutting tool holder in any manner, non-rotatably or otherwise. 
     In use, such support blocks  12  can be distributed over and fastened to, such as by welding or any other suitable method, the circumference and length of a drum or other body (not shown) according to any desired pattern. The drum or other body may be driven by any conventional or suitable power means to cause the cutting tools  28  to engage and break up material that they are applied to. Such applications are well known in the art, and will not be described in further detail here. 
     The cutting tool  28  typically has an elongated body. A cutting end  30  typically comprises a hard cutting insert  32  mounted onto a generally conical outer region  34 . The hard cutting insert  32  may be made from cemented tungsten carbide or any other suitable material. The hard cutting insert  32  is generally mounted at the end of the conical outer region  34  where the hard cutting insert  32  may be brazed or otherwise suitably fastened into place. The cutting tool  28  also typically includes a cutting tool shank  36  adjoining a cutting tool shoulder  38  of the conical outer region  34 . Because such cutting tools are generally known in the art, they will not be described in further detail here. 
     The cutting tool holder  18  may have a variety of configurations. The cutting tool holder  18  shown in this embodiment has the outer wear portion  22  and the holder shank  20  joined at a holder shoulder  44 . The cutting tool holder  18  shown in this embodiment also defines a tool bore  46  in which the cutting tool  28  may be rotatably or otherwise mounted. Such rotatable or non-rotatable mountings are well known in the art, and will not be described in further detail here. 
     The holder shank  20  of the cutting tool holder  18  may itself also have a variety of configurations. In this embodiment, as shown in FIG. 2, the holder shank  20  has a shank axis  50  and a shank end  52 . The shank end  52  defines a shank wedge surface  54  which is inclined relative to the remainder of the holder shank  20  or the shank axis  50 . An angle of such inclination in the range of 12°-15° is believed suitable. In this particular embodiment, the shank wedge surface  54  has a first shank wedge surface portion  56  and a second shank wedge surface portion  58 . 
     In this embodiment, as shown in FIG. 2, the tool holder  18  also defines a holder pin bore  70  having a holder pin bore diameter  72 . In fact, in this embodiment, the holder pin bore  70  intersects at least a portion of the holder shank  20 . Furthermore, in this embodiment, as shown in FIG. 2, the holder pin bore  70  intersects the shank end  52  between the first shank wedge surface portion  56  and the second shank wedge surface portion  58 . 
     In this embodiment, as shown in FIG. 2, a pin bore recess  74  is located adjacent the pin bore  70  at the outer surface of the tool holder  18 . That pin bore recess  74  has a pin bore recess diameter  76 . In this embodiment, the pin bore recess  74  defines a pin bore shoulder  78  at the intersection of the pin bore recess  74  and the holder pin bore  70 . 
     Like cutting tool holders, the support block  12  may have a variety of configurations. As shown in FIGS. 1-2, in this embodiment the support block  12  has a block side surface  80  and a block base  82  which may be mounted to a drum or other body (not shown) by welding or any other suitable method. 
     The tool holder bore  14  of such a support block  12  is typically surrounded by a seating shoulder region  84 . The tool holder bore  14  of such a support block  12  has a bore axis  86  which is coincidental with the shank axis  50  when the components are assembled as shown in FIG.  2 . The tool holder bore  14  defines a bore interior surface  88  and has a bore opening  90  intersecting the seating shoulder region  84 . In this embodiment, the tool holder bore  14  also has a bore recess  92 . In this embodiment, as shown in FIG. 2, the bore recess  92  is defined by a secondary bore  94  which intersects the tool holder bore  14 . 
     The tool holder bore  14  of the support block  12 , and the tool bore  46  of the tool holder  18 , and accordingly the cutting tool  28 , are typically pitched in the direction of travel of the cutting tool  28 , designated as direction “A” on FIG.  1 . 
     Like the cutting tool holder  18  and support block  12 , the retainer  24  may have a variety of configurations. The retainer  24  together with the holder shank  20  are an effective shank  60 . Accordingly, the retainer  24  is also referred to as the retainer portion of the effective shank  60 . 
     As shown in FIG. 2, the retainer  24  of this embodiment has a retainer pin bore  100 . In this particular embodiment, the retainer pin bore  100  is threaded. 
     The retainer  24  also has a retainer wedge surface  102 , which, in this embodiment as shown in FIG. 2, slidingly engages the shank wedge surface  54 . In this particular embodiment, the retainer wedge surface  102  has a first retainer wedge surface portion  104  and a second retainer wedge surface portion  106  which slidingly engage the first shank wedge surface portion  56  and the second shank wedge surface portion  58  of the shank wedge surface  54  respectively when the components are assembled. As shown in FIG. 2, the first retainer wedge surface portion  104  and the second retainer wedge surface portion  106  are preferably located, as will be explained, on opposite sides of the retainer pin bore  100 . 
     In this embodiment, as shown in FIG. 2, the retainer  24  also has a retainer engagement surface  108  which engages the bore interior surface  88  of the tool holder bore  18  of the support block  12  when the components are assembled. While not required, in a preferred embodiment at least a portion of the retainer engagement surface  108  is a retainer compressible surface  110 . In this embodiment, the retainer compressible surface  110  may consist of an outer surface of compressible material  112  fastened to the retainer  24 . Any suitable material could be used as a compressible material  112  to define the retainer compressible surface  110 , such as any suitable rubber. Because such compressible material  112 , such as rubber, may have a higher coefficient of friction than a metallic surface, the holder shank  20  is more effectively retained within the tool holder bore  14  when the components are assembled as will be explained. Such compressible material  112  may have a male protrusion (not shown) which mates with a retainer recess (not shown) defined by the retainer  24  so as to connect the compressible material  112  to the retainer  24 . While not shown, such a male protrusion of the compressible material  112  may have an enlarged portion which could be compressed and forced into the retainer recess of the retainer  24  such that the enlarged portion would then expand within the retainer recess of the retainer  24  with the result of locking the compressible material  112  to the retainer  24 . Such compressible material  112  may also be fastened to the retainer  24  by using any suitable adhesive such as a weather strip adhesive. One such weather strip adhesive is sold by Minnesota Mining and Manufacturing Company. 
     As shown in FIG. 2, the cutting tool holder retention system  10  of this embodiment also includes the pin  26  having a pin threaded portion  120  which threadably engages the threaded retainer pin bore  100  of the retainer  24 . The pin  26  also has a pin diameter  122 . In this embodiment, the pin  26  also has a pin head  124  which engages the pin bore shoulder  78  such that the pin  26  may be rotated so as to draw the retainer  24  toward the shank end  52  when the components are assembled as shown and used as will be explained. It is preferable that the pin head  124  be located in a recess, such as the pin bore recess  74  shown, to nimize damage to the pin during use. It has been found suitable to use a ⅜ Grade 8 socket head cap screw as the pin  26  together with a spherical seat with Bellville washers (shown at  126 ). Of course, any suitable pin, and any suitable arrangement, could be utilized. 
     When the retainer  24 , also referred to as the retainer portion of the effective shank  60 , is assembled with the holder shank  20  and the pin  26  as shown in FIG. 2, the retainer  24  and holder shank  20  together define an effective shank dimension  130  which is adjustable as will be explained. In the embodiment shown, the effective shank dimension  130  is the distance between the retainer engagement surface  108  and that side of the holder shank  20  opposite the retainer engagement surface  108 . 
     To use the embodiment of this invention shown in FIGS. 1-3, the pin  26  is inserted into the holder pin bore  70  of the tool holder  18 . The retainer  24 , also referred to as the retainer portion of the effective shank  60 , is then loosely threaded onto the pin threaded portion  120  of the pin  26 . The holder shank  20  of the tool holder  18 , including the retainer  24 , may then be inserted into the tool holder bore  14  of the support block  12  with or without the cutting tool  28 , as shown in FIG.  2 . 
     The pin head  124  may then be rotated so that the retainer  24  will be drawn toward the shank end  52  of the holder shank  20  via the threaded engagement between the pin threaded portion  120  of the pin  26  and the threaded retainer pin bore  100  of the retainer  24 . 
     As shown in FIG. 3, when the retainer  24  is drawn toward the shank end  52  of the holder shank  20 , the retainer wedge surface  102  will slidingly engage the shank wedge surface  54  such that the retainer  24  will move laterally with respect to the shank axis  50  thus increasing the effective shank dimension  130 . More specifically, in the particular embodiment shown in FIGS. 1-3, the first retainer wedge surface portion  104  and the second retainer wedge surface portion  106  will slidingly engage the first shank wedge surface portion  56  and the second shank wedge surface portion  58  respectively so as to expand the effective shank dimension  130 . 
     More specifically, as the effective shank dimension  130  expands the retainer engagement surface  108  and that portion of the holder shank  20  opposite the retainer engagement surface  108  will be forced against the bore interior surface  88  of the tool holder bore  14 . As a result, the retainer engagement surface  108  and the holder shank  20  cooperate to retain the holder shank  20  within the tool holder bore  14  of the support block  12  during use. 
     In this particular embodiment, the retainer engagement surface  108  and the holder shank  20  cooperate to retain the holder shank  20  within the tool holder bore  14  of the support block  12  by way of frictional engagement with the bore interior surface  88  of the tool holder bore  14 . However, while not shown, it is anticipated that such retention could result solely from or be augmented by such a system where a protrusion from the side of the retainer  24  or holder shank  20 , would be caused to protrude into a recess in the bore interior surface  88 . 
     As shown in FIG. 3, when the retainer  24  is forced laterally relative to the shank axis  50  in this particular embodiment, the retainer compressible surface  110  is compressed against the bore interior surface  88 . This further serves to increase the frictional engagement between the retainer engagement surface  108  of the retainer  24  and the tool holder bore  14  of the support block  12 . Furthermore, as shown in FIG. 3, when the tool holder bore  14  of the support block  12  includes a bore recess  92 , and the components are assembled as shown, the retainer compressible surface  110  is forced to protrude into the bore recess  92 , further locking the components together. 
     When it is desired to change the cutting tool holder  18 , the pin head  124  is rotated in the opposite direction such that the retainer  24  is forced away from the shank end  52  of the holder shank  20 . When the components are sufficiently loosened, the holder shank  20  of the tool holder  18  may be simply removed from the tool holder bore  14  of the support block  12 . 
     One advantage of the cutting tool holder retention system is that the components are relatively simple to manufacture and to use. 
     Another advantage of this cutting tool holder retention system is the relative simplicity of relying on an expandable effective shank to retain the holder shank  20  within the tool holder bore  14  of the support block  12 . 
     Yet another advantage of this cutting tool holder retention system is that relatively large retention forces may be generated by the sliding engagement between the retainer wedge surface  102  and the shank wedge surface  54 . 
     In embodiments where the retainer  24  has a retainer compressible surface  110 , another advantage is that the retainer compressible surface  110  is compressed against the bore interior surface  88  so as to accentuate retention when the retainer  24  is drawn toward the shank end  52  of the holder shank  20  when the pin  26  is rotated. This effect is increased in embodiments where the tool holder bore  14  includes the bore recess  92  such that when the retainer  24  is drawn toward the shank end  52  of the holder shank  20 , the retainer compressible surface  110  is compressed so as to protrude into the bore recess  92  of the tool holder bore  14  and further retain the components together. 
     In embodiments where the retainer wedge surface  102  consists of a first retainer wedge surface portion  104  and a second retainer wedge surface portion  106  bisected by the retainer pin bore  100 , the resulting double seat arrangement also provides the advantage of minimizing bending forces on the pin  26 . 
     While particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications may be made, and other embodiments utilized, without departing from the scope of this patent. It is intended that the following claims cover all such modifications and embodiments, and all other modifications and embodiments, and all equivalents of such modifications and embodiments, that fall within the spirit of this invention.