Abstract:
A seal assembly for a toolholder with a collet clamping member having a forcing ring in which at least in part the clamping member can be positioned, and a seal ring with a tool insertion opening including a surrounding O-ring holder that can be removably engaged with the forcing ring to place this seal ring in a selected position therein. An O-ring is provided in the seal ring O-ring holder.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     None 
     BACKGROUND OF THE INVENTION 
     The present invention relates to cutting tools such as drills having a liquid as both a coolant and a lubricant supplied to the cutting face of the tool and the material being cut and, more particularly, to liquid flow path restrictions for such tools. 
     Tools that are used to cut through hard material operate in the presence of large amounts of heat generated thereby and undergo rapid wear of the tool cutting surface in the absence of measures to reduce same. One such measure is to provide a liquid serving as both a coolant and a lubricant at the tool cutting surface where it engages the material being cut. In one such situation, in which a drill is being used to form a hole in a hard material, such a drill can be provided with an interior fluid flow channel to allow transport therethrough of such a liquid under substantial pressure to the interface between the drill and the material thereby allowing that liquid to serve as both a coolant and a lubricant for the drill cutting surface. Such a liquid brought to the drill cutting surface in addition aids in forcing out cut away portions of the material being cut as well as aiding in preventing the drill bit from overheating which can lead to increased tool wear or even breakage. 
     In such a cutting situation, the liquid pressure may have to be quite large for the liquid to be effective at the tool cutting surface where it meets the material being cut. Liquid pressures from a few hundred pounds per square inch to thousands of pounds per square inch may be needed depending on the particular situation. Fluid confinement in the toolholder at appropriate locations and in the interior fluid flow channel of the tool except at the orifices of that channel where the liquid exits onto the tool cutting surface is necessary if such liquid pressures are to be maintained during operation of the tool. Thus, the pressurized liquid must be confined to flowing with respect to the tool only through the transfer channel and out the orifices thereof in the cutting tool surface, and not along other circumventing paths. That is, the liquid from the pressurized reservoir thereof in the toolholder must flow through the transport channel in the drill and not through other parallel paths to the atmosphere. 
     One such parallel path for the liquid are leakage paths around the shaft of a drill bit being used as the operating tool. Such leakage has been limited in the past by providing some sort of a seal around the periphery of the drill bit so that fluid reaching the drill shaft from the pressurized reservoir is prevented, at least in large part, from flowing along the sides of the drill. One such seal is shown in U.S. Pat. No. 5,567,093 to the present inventor based on a rigid seal positioned at one end about the drill with an O-ring therebetween, and with the opposite end of the rigid seal being captured between the collet chuck and the collet nut so as to be held by the tightened nut against the collet chuck and the liquid pressure. However, changes in shapes of collets and collet nuts that have previously been commonly used, and increases in liquid pressures being used, can limit the suitability of such a rigid seal. Thus, there is a need for a tool shaft seal system in connection with a toolholder that accommodates various collet chuck shapes and higher liquid pressures for liquids used as a coolant and lubricant at the cutting surface of the tool during operation thereof in cutting materials. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a seal assembly for a toolholder with a collet clamping member about an extended tool placement opening that can be forced radially inward to clamp a tool having a forcing ring in which at least in part the clamping member can be positioned with a seal ring opening positioned adjacent to, and coaxially with, the clamping member with this opening having an inner surface supporting an engager accommodation such as threading. A seal ring with a tool insertion opening including a surrounding O-ring holder has an outer surface supporting an engager, such as threading, that can be removably engaged with the forcing ring engager accommodation in the forcing ring seal ring opening to place this seal ring in a selected position therein. An O-ring is provided in the seal ring O-ring holder. The seal ring has a pair of ends with one of these ends having a pair of holes therein opposite one another across the tool insertion opening. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a truncated side view including a partially cutaway view of a toolholder arrangement and assembled tool embodying the present invention, 
     FIG. 2 is an exploded perspective view of the toolholder shown in FIG. 1, 
     FIG. 3 is an exploded side view of the toolholder shown in FIG.  1  and tool including partially cutaway views, 
     FIG. 4 is an exploded perspective view of an alternative toolholder embodying the present invention, 
     FIG. 5 is an exploded side view of the toolholder shown in FIG.  4  and tool including partially cutaway views, and 
     FIG. 6 is an end view of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 is a truncated side view, including a partially cutaway view portion,  10 , of a toolholder with an assembled tool showing a chuck,  11 , with jaws,  12 , clamping a toolholder extension,  13 , at one end thereof. Chuck  11  has a liquid transport channel,  14 , in the interior thereof connected to a reservoir of liquid in the toolholder provided under substantial fluid pressure to serve as a coolant and a lubricant for tools held in, or ultimately held by, this chuck. Such a liquid is thereby present in extension  13  again under this substantial fluid pressure. 
     Extension  13 , at its opposite end, has an interior surface portion,  15 , which tapers outwardly from the smallest inner diameter of extension  13  to a largest interior diameter occurring at this very end thereof to thereby have a taper angle with the length axis of symmetry of extension  13 . The outside of extension  13  at this same end has a threaded surface,  16 , thereabout that is more clearly seen in FIGS. 2 and 3. 
     Interior tapered surface  15  at the tool end of extension  13  forms a chamber at that end in which a collet chuck,  17 , can be inserted so that an outer long tapered surface portion,  18 , thereof is closely mated with interior tapered surface  15  of extension  13 , i.e. has a taper angle with respect to the length axis of symmetry of collet  17  similar to that of surface portion  15  with respect to the length axis of symmetry of extension  13 . Outer long tapered surface  18  of collet  17  ends at a collet nut capture channel,  19 , recessed into the outer surface of collet  17  on the other side of which the remainder of the outer surface of collet  17  is formed by a short tapered surface,  20 . Outer long tapered surface portion  18 , at the end thereof opposite the end thereof adjacent to channel  19 , ends at an end,  21 , of collet  17 , and outer short tapered surface portion  20 , at the end thereof opposite the end thereof adjacent to channel  19 , ends at a second end,  22 , of collet  17 . 
     Outer surface portions  18 ,  19  and  20  of collet  17  are the outer surface portions of a collet wall structure,  23 , which is formed about a tool placement opening,  24 , which has a truncated cylinder shape, and opening  24  extends through collet  17  from end  21  to end  22 . A set of slots,  25 , extend from collet end  21  through collet wall structure  23  for substantial distance toward end  22 . Similarly, a set of slots,  26 , extend from end  22  through wall structure  23  a substantial portion of the way towards end  21  with slots in this set alternating with those in set  25  around the periphery of collet  17 . Thus, a radially directed inward force on outer tapered short wall surface portion  20  of collet  17  causes portions of collet wall  23  to be moved radially inward from an unforced position to being against a tool shaft provided in tool placement opening  24 . 
     Such a radially directed inward force on outer tapered short wall surface portion  20  of collet  17  can be provided by tightening a collet nut,  30 , onto the end of extension  13  over collet  17  positioned in the chamber in extension  13  formed by interior tapered surface  15  thereof. Collet nut  30  has an approximately truncated cylindrical outer surface with some depressed portions provided therein to aid in gripping it, and this outer surface extends between a first end,  31 , and a second end,  32 . 
     An extension opening,  33 , approximating a truncated cylinder extends into collet nut  30  inward from end  31 , and a seal ring opening,  34 , also approximating a truncated cylinder extends inward into collet nut  30  from end  32  thereof. The inner surface of collet nut  30  about extension opening  33  at end  31  thereof is threaded to provide a threaded interior surface portion,  35 , which can mate and engage with the threads on threaded surface  16  at the end of extension  13 . The interior surface of collet nut  30  about seal ring opening  34  at end  32  thereof is also threaded to form a threaded interior surface portion,  36 . 
     A clamping structure opening,  37 , is provided between extension opening  33  and seal ring opening  34  within collet nut  30  to form a continuous opening therethrough. Clamping structure opening  37  has atapered interior surface portion,  38 , of collet nut  30  thereabout with a taper angle with respect to the length axis of symmetry of collet nut  30  substantially matching that of outer short tapered surface portion  20  of collet  17  with respect to the length axis of symmetry of collet  17 . Tapered surface  38  extends between a circular shoulder,  38 ′, formed at the interior end of seal ring opening  34  and a circular opening constriction ridge,  38 ″, formed at the interior end of extension opening  33 . Circular opening constriction ridge  38 ″ fits in collet nut capture channel  19  of collet  17  when mated therewith in mounting a tool in extension  13 . Alternatively, rather than being formed as part of collet nut  30 , tapered interior surface portion  38  and circular shoulder  38 ′ can be provided by a tapered opening ring and held in an extension of extension opening  33  in collet nut  30  by a snap ring also serving as circular opening constriction ridge  38 ″. 
     Thus, when collet  17  is in the end of extension  13  and collet nut  30  has the threaded surface  35  thereof engaged with threaded surface  16  of extension  13  sufficiently, tapered interior surface  38  of collet nut  30  is forced against outer short tapered surface portion  20  of collet  17 , and tapered interior surface  15  of extension  13  is forced against outer long tapered surface portion  18  of collet  17 , to thereby force wall structure  23  at tapered surface portion  20  inward so as to clamp a tool shaft provided in tool placement opening  24  of collet  17 . An example of such a tool shaft is shown provided as part of a drill,  39 , having a liquid transport channel,  39 ′, therein extending through the length thereof. 
     A seal ring,  40 , has an O-ring channel,  41 , formed therein about a tool insertion opening,  42 , otherwise shaped as a truncated cylinder. An O-ring,  43 , is shown positioned in channel  41  in FIGS. 1 and 3 but outside of ring  40  in FIG.  2 . The exterior surface otherwise approximating a truncated cylinder of seal ring  40  is threaded to form a threaded surface,  44 , that can mate with threaded surface  36  of collet nut  30  so as to be rotatable therein to a position against shoulder  38 ′ in collet nut  30 . 
     As a result, in the mounted tool assembly shown in FIG. 1, pressurized liquid provided in extension  13  is also at the base of the shaft portion of drill  39  from which it flows through drill liquid transport channel  39 ′. The pressurized liquid is also forced through the slots in collet  17 , and about collet  17 , into collet nut  30  but is prevented from leaving collet nut  30  at end  31  thereof by the mating of threaded surface  35  of that collet nut and threaded surface  16  of extension  13 . The pressurized liquid is also prevented from flowing through seal ring opening  34  of collet nut  30  by the mating of threaded surface  36  of collet nut  30  with threaded surface  44  of seal ring  40 . Finally, the pressurized liquid is prevented from flowing along the sides of drill shaft  39  by tightly fitted O-ring  43  held thereagainst by sealing ring  40 . 
     Collet nuts and extensions are formed of high quality steel and have substantial wall thicknesses to withstand high torques thereon occurring during tightening one on the other, and therefore can withstand large internal fluid pressures. Seal ring  40 , having a substantial thickness, is also well able to withstand the liquid pressures encountered as is its threaded mating with collet nut  30 . 
     A newer geometric form for the collet chuck and corresponding collet nut is shown in the exploded perspective view of an alternative toolholder of FIG.  4  and the exploded side view thereof shown in FIG. 5 again with the shaft of a drill shown as the tool to be held. This collet chuck,  17 ′, again has outer long tapered surface portion  18  extending between collet end  21  and circumferential collet nut capture channel  19  recessed into the outer surface of collet  17 ′. However, a much shorter outer short tapered surface portion,  20 ′, extends between channel  19  and the remaining collet end,  22 ′. The correspondingly changed wall structure,  23 ′, however still has slot sets  25  and  26  therein as formed about tool placement opening  24 . 
     Because of the geometry changes in collet chuck  17 ′ from the geometry of collet chuck  17 , a changed collet nut,  30 ′, is correspondingly provided as shown in FIGS. 4 and 5. Collet nut  30 ′ again has extension opening  33  with threaded interior surface portion  35  thereabout extending into collet nut  30  inward from end  31 , and seal ring opening  34  with threaded interior surface portion  35  thereabout extending inward into collet nut  30  from end  32  thereof. However, clamping structure opening  37  between extension opening  33  and seal ring opening  34  now has no significant tapered interior surface portion  38  thereabout extending between circular shoulder  38 ′ and circular opening constriction ridge  38 ″ which instead are immediately adjacent one another in collet nut  30 ′. 
     In tightening collet nut  30  onto collet  17  above in FIGS. 1,  2  and  3 , tapered interior surface  38  of collet nut  30  is forced against outer short tapered  5  surface portion  20  of collet  17  but can come against it off center to leave collet  17  with tool  39  canted off center. However, tightening collet nut  30 ′ onto collet  17 ′ here results in the left side of channel  19  of collet  17 ′ being forced against circular shoulder  38 ′ so that the centerline of collet  17 ′ must align with the centerline of collet nut  30 ′, i.e. without any canting. 
     The same seal ring  40  and O-ring  43  used with collet nut  30  above can be used with collet nut  30 ′ here so that threaded surface  44  can be mated with threaded surface  36  of collet nut  30 ′ so as to be rotatable therein to a position against shoulder  38 ′ in collet nut  30 ′. Pressurized liquid can again be provided in extension  13  to the base of the shaft portion of drill  39  from which it flows through drill liquid transport channel  39 ′, and through the slots in collet  17 ′ and around collet  17 ′ into collet nut  30 ′ but is prevented from leaving collet nut  30 ′ by the mating of threaded surfaces with extension  13  and seal ring  40 . Again, the pressurized liquid is prevented from flowing along the sides of drill shaft  39  by tightly fitted O-ring  43  held thereagainst by sealing ring  40 . The high quality steel and substantial wall thicknesses of extension  13 , collet nut  30 ′ and seal ring  40  are well able to withstand the liquid pressures encountered. 
     An end view of seal ring  40  is shown in FIG.  6 . There can be seen four small recessed holes,  45 , symmetrically around tool insertion opening  42  on a common position placement circle of a radius larger than that of opening  42 . Pairs of holes  45  are across from one another on a diameter of that common position placement circle. Holes  45  are of a sufficient diameter to accept therein bosses on a spanner wrench to allow tightening of seal ring  40  in seal ring opening  34  of either of collet nuts  30  or  30 ′ against shoulder  38 ′ at the bottom of those openings to assure pressurized liquid does not flow past seal ring  40  where mated with a collet nut. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.