Patent Publication Number: US-6210083-B1

Title: Method of providing a cutting tool with lubricating coolant

Description:
CONTINUING APPLICATION DATA 
     This is a continuation from U.S. Ser. No. 09/020,020 filed on Feb. 6, 1998, now U.S. Pat. No. 6,116,825 which claims continuation-in-part status from International Patent Application No. PCT/EP96/03489, filed Aug. 7, 1996, which claims priority from Fed. Rep. of Germany Patent Application No. 295 12 745.7, filed Aug. 8, 1995, and Fed. Rep. of Germany Application No. 296 02 997.1, filed Feb. 21, 1996. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Method of providing a cutting tool with lubricating coolant. 
     2. Background Information 
     One problem encountered in the cutting of work pieces, and of metal work pieces in particular, is that the boring tool, such as a drill, reamer or a rotating tool in general (the following description relates in particular to drills), heats up during the cutting process along with the material of which the work piece is made. In automatic mass production operations in particular, cooling and lubrication using a lubricating coolant (designated a “lubricant” below) is therefore necessary. In wet machining processes, a large excess of liquid lubricant is introduced into the hole as it is being drilled. This type of lubricating and cooling action entails relatively high costs for equipment, not to mention the costs of the lubricant supply, the necessary cleaning, etc. In drilling operations, moreover, it is not always possible to deliver the lubricant directly into the hole being drilled. Therefore, lubricating systems are used in which the lubricant is transported by means of transport devices via the spindle of a drilling machine and at least one lubricant channel in the drill to the site of the drilling. The site of the drilling is approximately in the vicinity of the major cutting edges or the chip faces of the drill. In these known lubrication systems a relatively large quantity of lubricant is required, because the supply lines which lead from the supply device to the drill or to the spindle of the drill must be filled with lubricant. In addition, a precise and controlled dispensing of small quantities of lubricant is very difficult to achieve using the conventional delivery devices. 
     OBJECT OF THE INVENTION 
     The object of the present invention is therefore a method, as well as a boring tool and tool holder to carry out the method, to accurately dispense a controlled and extremely small quantity of lubricant using technically simple means. 
     SUMMARY OF THE INVENTION 
     The present invention teaches that this object can be accomplished in accordance with one possible embodiment by a method for supplying rotating cutting tools, in particular a drill, with a lubricant which is used for cooling and/or lubrication. The lubricant is contained in a reservoir which is connected directly or indirectly to the boring tool and which reservoir functions as a dispenser from which the lubricant is transported through at least one lubricant channel and at least one discharge opening in the boring tool to a working part to be lubricated and/or cooled. 
     The present invention teaches that this object can also be accomplished in accordance with one possible embodiment by a boring tool, in particular a drill, to carry out the method. The boring tool has a shank, a cutter and at least one internal lubricant channel. At least one reservoir which functions as a dispenser for a lubricant is directly or indirectly connected mechanically to the boring tool and hydraulically to the at least one lubricant channel. 
     In addition, the present invention teaches that this object can be accomplished in accordance with one possible embodiment by a tool holder for holding a boring tool. The tool holder has an integrated dispenser for a lubricant, whereby the dispenser, when the boring tool is held in the tool holder, is hydraulically connected to at least one internal lubricant channel of the boring tool. 
     In the method of the present invention, a lubricant which is used for cooling and/or lubrication is contained in a reservoir. The reservoir acts as a dispenser and is directly or indirectly connected to the boring tool. The lubricant is transported from this dispenser to the respective working parts by at least one lubricant channel in the boring tool. 
     An advantage of the method taught by the present invention is that expensive supply devices, relatively expensive rotary transmission feed-throughs or adjustable pump units are no longer necessary. The dispenser can be connected directly to the boring tool, for example, and rotates along with the boring tool during the cutting of the work piece. A further advantage of the method taught by the present invention is that a precisely controlled quantity of lubricant can be made available for one, or preferably, for a plurality of drilling processes. For example, it is also conceivable that a dispenser, which dispenser is integrated into the shank of a boring tool, can contain a quantity of lubricant which is sufficient for the entire useful life of the boring tool. Such a boring tool can always be independently supplied with a sufficient quantity of lubricant, in particular, an extremely small quantity of lubricant, from a lubricant supply device which is installed on a drilling machine. 
     In one method taught by the present invention, there are a variety of possibilities for the propulsion of the lubricant flow during a drilling or cutting process. The propulsion force for the lubricant flow can advantageously be generated by locating the dispenser above the working parts of the boring tool. This situation occurs when the drilling operation is essentially from top to bottom. In an embodiment where discharge openings are located on the side of the boring tool, the centrifugal force which is generated by the rotation of the boring tool also acts on the lubricant. The lubricant transport caused by the hydrostatic pressure of the dispenser, which dispenser is located above the working parts, is therefore generally assisted by centrifugal forces. To prevent the lubricant from escaping when the boring tool is not in use, it is advantageous to use a lubricant which is solid or highly viscous at room temperature and which liquefies at the temperatures which are encountered during cutting operations. The lubricant, which is solid or highly viscous at room temperature, is retained in the lubricant channel by adhesion or cohesion forces. When the boring tool is in use, the boring tool heats up after a brief period of operation to a point where the lubricant is converted into a liquid or less viscous state. Gravity then acts on the lubricant, as well as the centrifugal forces in the vicinity of the discharge openings, so that the lubricant is transported to the working parts of the boring tool. The lubricant can also be liquid even at room temperature, in which case the lubricant can be prevented from escaping through the discharge openings by coordinating the cross sectional area of the discharge opening and the viscosity of the lubricant so that the adhesion and cohesion forces are greater than the forces generated by the hydrostatic pressure. 
     The transport of the lubricant to the working parts of the boring tool can also be advantageously promoted by a capillary fluid transport device. This term is used to include, among other things, sponge-like or fibrous storage media which are used to fill at least the lubricant channel or channels. It may also be advantageous if the dispenser is filled with such a storage medium. In this method, the lubricant is discharged from the discharge openings by centrifugal force, and the discharge of the lubricant may also be assisted by a temperature-dependent reduction in viscosity. The lubricant, which lubricant is consumed in the working parts of the boring tool, is replaced by capillary action with lubricant which is discharged from the storage medium in the lubricant channel and the dispenser. The advantage of such a method is that the cooling and lubrication action can be accomplished practically independently of the current position of the boring tool. 
     Lubrication which is independent of the position of the boring tool is also possible if there is pressure in the dispenser or if such a pressure is generated. In this manner, even higher-viscosity lubricants and those lubricants which do not sufficiently liquefy even at the operating temperatures and which could not be transported to the working parts without the application of pressure can be used. The quantity of lubricant or the lubricant flow can generally be controlled without entailing any major expense or effort by selecting an appropriate size of the discharge openings. With reference to a defined speed of rotation of the boring tool, it thereby becomes possible to achieve a relatively precisely controlled flow of lubricant. 
     In one method taught by the present invention, the dispenser can be integrated into the boring tool itself. A tool which is particularly suitable for this method is a drill with a shank, which shank has a corresponding cavity. The dispenser, however, can also be a separate reservoir which can be connected to the boring tool. An additional possibility is to locate the dispenser in a tool holder which is also used to hold the boring tool. 
     An embodiment of a boring tool which is suitable for carrying out the method taught by the present invention has a shank, a cutter and at least one internal lubricant channel. In addition, at least one dispenser is directly or indirectly connected mechanically to the boring tool and hydraulically to the at least one lubricant channel. In this manner, a boring tool is created which has an integrated lubrication system. As described above, this type of boring tool can be used independently of a lubricant supply device which is installed on a machine tool or drill. Since each drill carries its own supply of lubricant along with it, so to speak, it is possible to supply different types of drills with individual lubricants which are suited to the respective drilling conditions. This measure is not possible on conventional lubricant supply systems without additional major expense and effort. Likewise, the cleaning or changing of the lubricant in conventional lubricant supply systems is a relatively expensive and time-consuming process. 
     A dispenser taught by the present invention can be advantageously provided in the form of a recess, which recess is in the form of a blind hole in the shank of the boring tool. The recess extends from the shank-side end surface toward the cutter of the boring tool. 
     It is particularly advantageous if the dispenser is realized in the form of a removable cartridge, which removable cartridge can be inserted into a receptacle recess in the shank of the drilling tool. It is then possible, for example, on high-quality boring tools which have long operating lives, to refill an empty lubricant reservoir very easily. In this manner it is also possible to keep the dispensers small and also to keep the quantity of lubricant stored in the boring tool small. To make the lubricant replacement process as easy as possible, it is advantageous if the replacement cartridge has a ball check valve with a closing ball which is spring-loaded in the closing direction. The ball check valve is moved into its open position in a known manner by an actuator tappet when the cartridge is inserted into the receptacle recess or when it has already been inserted. The actuator tappet can be effectively located on the bottom of the receptacle recess and the ball check valve can be located on the end of the cartridge. 
     A replaceable dispenser can also be realized in the form of a separate detachable container which can be detachably connected to the end of the boring tool. Such a container can be hydraulically connected to a lubricant channel in the drill by a connecting tube on the shank-side end surface of the drill. The connecting tube can penetrate into the interior of the detachable container via an opening in the container. The connecting tube has a connecting channel which is hydraulically connected to the lubricant channel. 
     To assist the transport of lubricant, it is advantageous if the dispenser is pressurized. Such a pressurization can be advantageously realized by an expanding gas cushion. Such a gas cushion can either be present in the dispenser from the beginning, or can be generated only when needed. For example, the container can be separated by a separating piston into a lubricant chamber and a gas generation chamber. In the gas generation chamber, there is an electrolysis liquid into which a solid material can be introduced as needed, whereupon the solid material reacts with the electrolysis liquid, generating a gas. 
     It is also possible and advantageous, however, to realize the pressurization in the form of a spring-loaded compression piston. The boring tool can be used in any desired position both when the dispenser is pressurized and when capillary storage media are used. On all the exemplary embodiments described so far, the dispenser is preferably refillable. To guarantee this refilling capability, the dispenser is preferably provided with a check valve which can be unlocked from the outside. The check valve can be realized in the form of a spring-loaded ball check valve. Such a valve can be very easily unlocked by the discharge tube of a lubricant container. The dispenser can then be filled with lubricant. 
     In a boring tool as taught by the present invention, the lubricant channel is preferably realized in the form of a central channel, which channel extends coaxially to the longitudinal center axis of the drill. The channel, at least in the vicinity of the discharge openings, tapers toward the tip of the boring tool. This shape of the lubricant channel facilitates the flow of the lubricant, in particular the flow of a higher-viscosity lubricant. The closer a lubricant is to the working parts during operation, the less viscous it becomes. Accordingly, the cross section of the lubricant channel decreases as it comes closer to the working parts. A comparable effect can be achieved by a stepped boring, whereby the segment with the smallest diameter is located in the vicinity of the tip of the drill, which drill tip becomes hotter. Such a configuration is not absolutely necessary for the boring tool of the present invention. For example, there can also be several spiral lubricant channels, which channels run in a path which approximately follows the path of the chip flute. 
     On a tool holder for holding a boring tool as taught by the present invention, the dispenser is integrated into the tool holder. The dispenser is hydraulically connected to at least one internal lubricant channel in the boring tool when the boring tool is in place in the tool holder. The advantage of such an arrangement is primarily that, on account of the larger volume of the tool holder, a correspondingly larger reservoir can be created for the lubricant, which can therefore contain sufficient lubricant for longer periods of operation. This type of lubricant supply is also independent of the machine-side lubricant supply devices such as pumps, connecting lines, rotary transmission feed-throughs etc. 
     The dispenser located in a tool holder can, if necessary, be filled with higher or lower viscosity lubricants. To prevent a loss of low-viscosity lubricants, in particular when the drill is not in operation, it is advantageous if the hydraulic connection between the dispenser and the lubricant channel of the boring tool can be controlled by a check valve, in particular a check valve which is actuated by centrifugal force. A boring tool can therefore be replaced without the danger of lubricant escaping from the dispenser. 
     To assist in the transport of the lubricant, it is appropriate if the dispenser, such as the boring tool of the present invention, can be pressurized by an expandable gas cushion or by a spring-loaded compression piston. To assist in the transport of the lubricant, a capillary storage medium can also be located in the lubricant channel of the boring tool to transport the lubricant from the dispenser, in which there is preferably also a capillary storage medium, to the working parts of the boring tool. The dispenser which is integrated into the tool holder is preferably refillable. 
     The above discussed embodiments of the present invention will be described further hereinbelow with reference to the accompanying figures. When the word “invention” is used in this specification, the word “invention” includes “inventions”, that is, the plural of “invention”. By stating “invention”, the Applicants do not in any way admit that the present application does not include more than one patentably and non-obviously distinct invention, and maintain that this application may include more than one patentably and non-obviously distinct invention. The Applicants hereby assert that the disclosure of this application may include more than one invention, and, in the event that there is more than one invention, that these inventions may be patentable and non-obvious one with respect to the other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is explained in greater detail below with reference to the exemplary embodiments of a drill illustrated in the accompanying drawings, wherein: 
     FIG. 1 shows a side view of a drill in longitudinal section, and in which drill the dispenser is formed by a recess in the drill shank; 
     FIG. 2 shows a drill as illustrated in FIG. 1, but with a lubricant channel positioned coaxially and tapered toward the tip of the drill; 
     FIG. 3 shows a drill in a similar view as in FIG. 1, but with a central, coaxially positioned lubricant channel in the form of a stepped boring; 
     FIG. 4 shows a drill with a dispenser realized in the form of a replaceable cartridge; 
     FIG. 5 shows a drill in which the dispenser and a central lubricant channel are filled with a porous or capillary storage medium; 
     FIG. 6 shows a drill, to the end surface of which drill is connected a separate detachable container in the form of a dispenser; 
     FIG. 7 shows a tool holder having an integrated dispenser, which dispenser can be pressurized by a spring-loaded piston; and 
     FIG. 8 shows a tool holder with an integrated dispenser, which dispenser can be pressurized by an expandable air cushion. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a drill as taught by the present invention which drill can be divided into a shank  1  and a cutter  2 . The cutter  2  preferably has two chip flutes  3 , which chip flutes  3  extend in a spiral pattern around a longitudinal center axis  4  of the drill. In the shank  1  of the drill there can be a recess  5 , which recess  5  can be positioned coaxially around the longitudinal center axis  4 . The recess  5  can also extend in the form of a blind hole from a shank-side end  6  of the drill toward a drill tip  7 . The recess  5  preferably functions as a dispenser  9  to hold a lubricant. Two lubricant channels  10  can emerge in a bottom  8  of the dispenser  9  and can extend through to the drill tip  7 . At that point, the lubricant channels  10  can emerge into flanks  11  of the major cutting edges of the drill. Preferably, the discharge openings of the lubricant channels  10  in the flanks  11  are plugged with a solder or an equivalent material. In the vicinity of the cutter  2 , close to the drill tip  7 , there can be a plurality of branch channels  14 . The branch channels  14  can extend from the back  15  of the drill to the lubricant channel  10  corresponding to the back  15  of the drill. By means of these branch channels  14 , which branch channels  14  can extend approximately radially out from the lubricant channel  10 , during the cutting process, the lubricant is discharged by discharge openings  13  and reaches the current working parts, in this embodiment, on the back  15  of the drill and on chip faces  31  in the vicinity of the cutter edge  16  of the drill, as well as the adjacent areas toward the shank  1 . The lubricant in the branch channels  14  can be transported outward by centrifugal force. The quantity of lubricant can be controlled by an appropriate selection of the cross sectional surface of the branch channels  14 . It is appropriate if the diameter of the lubricant channels  10  decreases as the distance from the drill tip  7  increases. It is thereby guaranteed that the greater quantity of lubricant will reach the actual work site, namely in the vicinity of major cutting edges  12 . 
     In another possible embodiment of the present invention, the diameter of the lubricant channels  10  can increase as the distance from the drill tip  7  increases. 
     The dispenser  9  can be pressurized. For this purpose, the dispenser  9  can have a compression piston  17 , which compression piston  17  moves in the axial direction and is sealed by O-rings  18  with respect to the inner wall of the dispenser  9 . A compression spring  19  is supported on one hand on the shank-side end of the compression piston  17  and on the other hand on a cover plate  20 . The cover plate  20  can be closed flush with the end  6  of the drill. As a result of the action of the compression spring  19 , the lubricant enclosed between the bottom  8  of the dispenser  9  and the compression piston  17  is preferably pressed into the lubricant channels  10 . The viscosity of the lubricant, the force of the compression spring  19  and the cross sectional areas both of the lubricant channels  10  and also of the branch channels  14  and the discharge openings  13  can be coordinated with one another so that with a specified viscosity of the lubricant at room temperature, practically no lubricant is pressed out of the branch channels  14 . Only when the system heats up during the cutting process, i.e. when the viscosity of the lubricant decreases, does the lubricant become less viscous, and lubricant can then be transported outward through the branch channels  14 . 
     The compression piston  17  is penetrated by a filling channel  21 , in which filling channel  21  there is a ball valve. The ball valve can be pressurized in the closing direction by a compression spring  22 . The closing element of this ball valve, namely a closing ball  23 , is preferably pushed by the spring  22  against a valve seat which surrounds a filling opening  24 . The dispenser  9  can thereby be closed. For refilling, a hollow needle can be introduced into the filling opening  24  by means of an insertion opening  25  in the cover plate  20 , and the closing ball  23  can thereby be raised from its seat. In this manner, the dispenser  9  can be refilled with lubricant. 
     In another possible embodiment of the present invention, the dispenser  9  can be refilled by removing the cover plate  20 . After the cover plate  20  has been removed the compression spring  19  and the compression piston  17  can be removed from the recess  5  of the shank  1 . Lubricant can then be inserted into the dispenser  9  and the compression spring  19  and the compression piston  17  can be replaced in the recess  5 . Finally, the cover plate  20  can be reconnected to the shank  1 . 
     In yet another possible embodiment of the present invention, the dispenser  9  can be refilled through a refill opening (not shown) in the side of the shank  1 . The refill opening can preferably be connected to the dispenser  9  to allow lubricant to be added to the dispenser  9 . The refill opening can be sealed by a valve or cover to prevent any leakage of lubricant from the dispenser  9  while the drill is in operation. 
     The drill illustrated in FIG. 2 differs from the drill illustrated in FIG. 1 essentially in that instead of two lubricant channels  10 , there is a single lubricant channel  10   a.  The lubricant channel  10   a  can extend coaxially to the longitudinal center axis  4  of the drill. The lubricant channel  10   a  ends blind at some distance ahead of the drill tip  7 , and extends in the direction of the shank  1  to the dispenser  9 . The diameter  41  of the lubricant channel  10   a  is preferably greatest in the vicinity of the bottom  8  of the dispenser  9 , and decreases continuously toward the drill tip  7 . The taper of the lubricant channel  10   a  can be similar to the taper in the drill illustrated in FIG.  3 . In this embodiment, the lubricant channel  10   b  from the dispenser  9  to the drill tip  7  does not taper continuously, but in steps. The lubricant channel  10   b  can therefore be realized in the form of a stepped boring. Overall, the lubricant channel  10   b  can have three areas with different diameters, whereby a first area having the largest diameter is adjacent to the bottom  8  of the dispenser  9  in the direction of the drill tip  7 . Approximately at the line separating the shank  1  and the cutter  2 , the lubricant channel  10   b  can become narrower. This area having the intermediate diameter can end approximately in the center of the cutter  2 , and can be adjacent on the other side to an area  26  having an even smaller diameter. Branching off from this area  26  of the lubricant channel  10   b  are a plurality of branch channels  14  which emerge at discharge openings  13  in the back  15  of the drill and in the chip face  31 . The flow of a highly-viscous lubricant can be facilitated by the shape of the lubricant channel  10   a ,  10   b  illustrated in FIGS. 2 and 3. 
     FIG. 4 illustrates a drill having a replaceable dispenser. In this embodiment, the dispenser can be realized in the form of a replacement cartridge  27 . The replacement cartridge  27  can be inserted into a receptacle recess  28 , which receptacle recess  28  has a matching shape, in the shank  1 . There can be a ball check valve  29  on the end of the replacement cartridge  27  facing the drill tip  7  when the cartridge  27  is in place. In the embodiment illustrated in FIG. 4, the cartridge  27  has not yet been inserted into the receptacle recess  28 . When the cartridge  27  is preferably moved from the position illustrated in FIG. 4 in the direction indicated by the arrow  30 , the ball  51  in the ball check valve  29  strikes an actuator tappet  32 , which actuator tappet or pin  32  is located on the bottom  8  of the receptacle recess  28 , the ball check valve  29  can thereby be moved into its open position, similar to a fountain pen. The lubricant can then travel into the receptacle recess  28  and into the lubricant channel  10 . 
     In another possible embodiment of the present invention, a piston and spring could be built into the replacement cartridge  27  to add a pressurization force to the lubricant stored in the replacement cartridge  27 . This pressurization force could assist the flow of lubricant from the replacement cartridge  27  to the lubricant channel  10 . 
     In the embodiment illustrated in FIG. 5, there can be a central lubricant channel  10  which emerges into a dispenser  9 . The dispenser  9 , like the drill in FIG. 1, can be formed by a recess  5 . The dispenser  9  and the lubricant channel  10  are preferably filled with a porous or capillary storage medium  33 ,  33   a . The material of the capillary storage medium  33 ,  33   a  can thereby be something on the order of a sinter material, with sponge-like cavities connected with one another, or a fibrous material. A relatively low-viscosity lubricant can be contained in the capillary cavities of the storage medium  33 . During operation of the drill illustrated in FIG. 5, the lubricant, which lubricant may have been liquefied by the heat of operation, can be discharged outward via the branch channel  14  by centrifugal force, and can be delivered to the working parts, i.e. approximately at the chip face  31 . On account of the capillary suction action produced by the storage medium  33 , the lubricant discharged at the working parts is continuously replaced. One of the major advantages of this embodiment is its technical simplicity. Neither a gas cushion nor any other pressure medium is required to transport the lubricant from the dispenser  9  to the working parts. The transport results solely from the capillary action of the storage medium, something like a felt-tip pen. The drill illustrated in FIG. 5 can also be operated in any desired position, without any reduction in its functionality or in the feed of the lubricant. It is also conceivable that there need not be any storage medium  33  in the dispenser  9  itself, and that the storage medium  33   a  in the lubricant channel  10  can extend, in the manner of a suction tube, through the interior of the dispenser  9 . 
     In another possible embodiment of the present invention, the storage medium  33  can be connected to the storage medium  33   a  at either the sides of the recess  5  or in the center of the recess  5  about the longitudinal center axis  4 . In addition, the storage medium could be refilled through a refill opening in either the shank-side end  6  or in the sides of the shank  1 . 
     In the drill illustrated in FIG. 6, the supply of lubricant is preferably not located inside the drill shank  1 , but in a separate detachable reservoir  34 , which reservoir  34  is preferably connected to the shank-side end  6  of the drill. For this purpose, the above-mentioned end  6  preferably has a connecting tube  35 . The connecting tube  35  can extend in the direction of the longitudinal center axis  4  and can be penetrated by a connecting channel (not shown). The two spiral lubricant channels  10   c  empty into the connecting channel. The detachable reservoir  34 , on its end facing the drill in the installed position, can have an opening which is encircled by a neck  36 . In the installed position, the connecting tube  35  is preferably inside the neck  36 , which creates a mechanical fastening of the detachable reservoir  34  to the drill or to the connecting tube  35 . 
     In another possible embodiment of the present invention, a piston and spring could be built into the detachable reservoir  34  to add a pressurization force to the lubricant stored in the detachable reservoir  34 . This pressurization force could assist the flow of lubricant from the detachable reservoir  34  through the connecting tube to the lubricant channels  10   c . 
     FIGS. 7 and 8 illustrate tool holders  37  as taught by the present invention. The tool holders  37  can have a conical retaining area  38 , by means of which retaining area  38  the tool holders  37  can be inserted into a corresponding fixture of a tool or machine tool (not shown). A second area  39  adjacent to the conical area  38  is preferably realized in a cylindrical shape, and on its end  40  can have a locator boring  42  for a drill  43 . Approximately in the central portion of the tool holder  37  and coaxial to a longitudinal center axis  44  of the tool holder  37 , there is preferably a dispenser  9   a . In the dispenser  9   a  there can be a compression piston  17   a , which compression piston  17   a  can be sealed with respect to the inner wall of the dispenser  9   a  by a compression spring  19   a . The compression spring  19   a  can be located in a spring chamber  45  which spring chamber  45  extends toward the conical retaining area  38  and can be connected to the dispenser  9   a . Connected to the compression piston  17   a  is a piston rod  46  which projects in the direction of the longitudinal center axis  44  into the spring chamber  45 . 
     In the drill  43  there is preferably a central lubricant channel  10  (not shown in FIG.  8 ), which lubricant channel  10  emerges on the shank-side end surface  6  of the drill  43 . In the tool holder  37  there can be a connecting channel  47 , which connecting channel  47  extends from the dispenser  9   a  to the end surface  6  or to the lubricant channel  10  which emerges in the end surface  6  of the drill  43 . The connecting channel  47  is preferably closed by a check valve  48  which is actuated by centrifugal force. The connecting channel  47  can be realized as follows in one possible embodiment. In a radial locator boring  49  there can be a valve gate  50  which is pressurized in the closing direction by a compression spring  52 . The compression spring  52  can be supported with its other end on a locking ball  53 . The cutoff or check valve  48  can operate as follows in one possible embodiment. When the drill  43  rotates, the valve gate  50  is moved radially outward by centrifugal force, against the force of the compression spring  52 . The valve gate  59  thereby exposes the cross section surface of the connecting channel  47 , at least partly. The lubricant which is under pressure in the dispenser  9   a  is then preferably transported via the connecting channel  47  into the lubricant channel  10  and finally to the working parts in the vicinity of the drill tip  7 . 
     The exemplary embodiment illustrated in FIG. 8 differs from the embodiment illustrated in FIG. 7 essentially in that the pressurization is produced by an expandable air cushion  54 . In the two embodiments illustrated in FIGS. 7 and 8, there can be a reclosable refill opening  55 , by means of which the dispenser  9   a  can be filled with lubricant. 
     In another possible embodiment of the present invention, the compression piston  17   a  can be sealed in the dispenser  9   a  by a seal or gasket  18   a  (see FIG.  7 ). The gasket  18   a  can be located around the entire circumference of the compression piston  17   a  to ensure an effective sealing of the compression piston  17   a  in the dispenser  9   a.    
     One feature of the invention resides broadly in the method for supplying lubricating coolant to rotating cutting tools, in particular a drill, with a lubricant which is used for cooling and/or lubrication, in which the lubricant is contained in a reservoir which is connected directly or indirectly with the boring tool and functions as a dispenser  9  from which the lubricant is transported by means of at least one lubricant channel  10  and at least one discharge opening  13  in the boring tool to a working part to be lubricated and/or cooled. 
     Another feature of the invention resides broadly in the method characterized by a transport of the lubricant to the working parts by gravity. 
     Yet another feature of the invention resides broadly in the method characterized by a lubricant which is solid or highly viscous at room temperature and which liquefies at the temperatures encountered during cutting. 
     Still another feature of the invention resides broadly in the method characterized by a lubricant which is a fluid at room temperature, whereby the cross sectional area of the discharge opening and the viscosity of the lubricant are coordinated with one another so that the lubricant does not escape from the discharge openings when the boring tool is not being used or is at room temperature. 
     A further feature of the invention resides broadly in the method characterized by the fact that the transport of the lubricant to the working parts of the boring tool takes place by means of a capillary fluid transport device. 
     Another feature of the invention resides broadly in the method characterized by the fact that the transport of the lubricant to the working parts of the boring tool is accomplished or assisted by a pressurization of the dispenser  9 . 
     Yet another feature of the invention resides broadly in the method characterized by the fact that the quantity of lubricant fed to the working parts is controlled by means of the size of the discharge openings. 
     Still another feature of the invention resides broadly in the method characterized by the fact that the dispenser  9  is integrated into the boring tool. 
     A further feature of the invention resides broadly in the method characterized by the fact that the dispenser  9  is a separate reservoir which can be connected to the boring tool. 
     Another feature of the invention resides broadly in the method characterized by the fact that the dispenser is integrated into a tool holder which holds the boring tool. 
     Yet another feature of the invention resides broadly in the boring tool, in particular a drill, to carry out the method with a shank  1 , a cutter  2  and at least one internal lubricant channel  10  characterized by at least one reservoir which functions as a dispenser  9  for a lubricant, and is directly or indirectly connected mechanically to the boring tool and hydraulically to the at least one lubricant channel  10 . 
     Still another feature of the invention resides broadly in the boring tool characterized by the fact that the dispenser  9  is formed by a recess  5  in the shank  2  of the boring tool, which. recess  5  is in the form of a blind hole which extends from the shank-side end surface  6  of the boring tool toward the cutter  2 . 
     A further feature of the invention resides broadly in the boring tool characterized by the fact that the dispenser  9  is a replaceable cartridge  27  which lies in a receptacle recess  28  in the shank  1  of the boring tool. 
     Another feature of the invention resides broadly in the boring tool characterized by the fact that the replaceable cartridge  27  has a ball check valve  29  located on its one end with a closing ball which is spring-loaded in the closing direction, and which when a replaceable cartridge  27  is inserted in the receptacle recess  28 , is held in its open position by an actuator lever  32  which is located on the bottom  8  of the receptacle recess  28 . 
     Yet another feature of the invention resides broadly in the boring tool characterized by a separate detachable reservoir  34  which is detachably connected to the shank-side end  6  of the boring tool and functions as a dispenser  9 . 
     Still another feature of the invention resides broadly in the boring tool characterized by a connecting tube  35  which can be inserted into an opening of the detachable reservoir  34 , and is penetrated by a connecting channel which is hydraulically connected to a lubricant channel  10 . 
     A further feature of the invention resides broadly in the boring tool characterized by the fact that the dispenser  9  is pressurized. 
     Another feature of the invention resides broadly in the boring tool characterized by the fact that an expandable gas cushion  54  is located in or can be generated in the dispenser  9 . 
     Yet another feature of the invention resides broadly in the boring tool characterized by a pressurization in the form of a spring-loaded compression piston  17  located in the dispenser  9 . 
     Still another feature of the invention resides broadly in the boring tool characterized by the fact that in the dispenser  9  there is a capillary storage medium  33  which works together with a capillary storage medium  33   a  in a lubricant channel  10   a.    
     A further feature of the invention resides broadly in the boring tool characterized by a refillable dispenser  9 . 
     Another feature of the invention resides broadly in the boring tool characterized by a filling channel  21  which extends through the compression piston  17 , with a check valve which can be unlocked from outside and is located in the filling channel  21 . 
     Yet another feature of the invention resides broadly in the boring tool characterized by at least one lubricant channel  10 , from which at least one small-diameter branch channel  14  branches off which emerges at a discharge opening  13  at a working part of the boring tool, whereby the branch channel and/or the discharge opening  13  have/has a smaller flow cross section than the lubricant channel. 
     Still another feature of the invention resides broadly in the boring tool characterized by a central lubricant channel  10   a  which runs coaxially to the longitudinal center axis  4  of the boring tool and which tapers toward the tip of the boring tool, at least in the vicinity of discharge openings  13 . 
     A further feature of the invention resides broadly in the boring tool characterized by a central lubricant channel  10   b  which runs coaxially to the longitudinal center axis  4  of the boring tool, and is realized in the manner of a stepped boring introduced from the shank end, whereby the branch channels  14  branch off from a smaller-diameter area  26  near the drill tip  7  of the boring tool. 
     Another feature of the invention resides broadly in the boring tool characterized by two spiral lubricant channels  10   c  with a path which corresponds to the path of the chip flutes  3  which are present in the cutter  2 . 
     Yet another feature of the invention resides broadly in the tool holder for holding a boring tool, characterized by an integrated dispenser  9   a  for a lubricant, whereby the dispenser, when the boring tool  43  is held in the tool holder, is hydraulically connected to at least one internal lubricant channel  10  of the boring tool. 
     Still another feature of the invention resides broadly in the tool holder characterized by the fact that the hydraulic connection between the dispenser  9  and the lubricant channel  10  can be controlled by means of a check valve  48  which is actuated by centrifugal force. 
     A further feature of the invention resides broadly in the tool holder characterized by the fact that the dispenser  9  is pressurized. 
     Another feature of the invention resides broadly in the tool holder characterized by the fact that an expandable gas cushion  54  is present in or can be generated in the dispenser  9   a.    
     Yet another feature of the invention resides broadly in the tool holder characterized by a pressurization in the form of a spring-loaded compression piston  17   a  which is located in the dispenser  9 . 
     Still another feature of the invention resides broadly in the tool holder characterized by the fact that in the dispenser  9   a  there is a capillary storage medium  33  which works together with a capillary storage medium  33   a  in a lubricant channel  30  of a boring tool which is held in the tool holder. 
     A further feature of the invention resides broadly in the tool holder characterized by a refillable dispenser  9 . 
     Another feature of the invention resides broadly in the tool holder characterized by a refill channel  55  which extends from the outside of the tool holder into the interior of the dispenser  9   a . 
     Some examples of drills and related components which may possibly be utilized or adapted for use in the context of the present invention may be disclosed in the following U.S. Pat. No. 5,377,773 to Tibbitts on Jan. 3, 1995; U.S. Pat. No. 5,380,133 to Schimmer on Jan. 10, 1995; U.S. Pat. No. 5,383,751 to Wheetley et al. on Jan. 24, 1995; U.S. Pat. No. 5,388,649 to Ilomaki on Feb. 14, 1995; U.S. Pat. No. 5,400,546 to Christian et al. on Mar. 28, 1995; U.S. Pat. No. 5,415,500 to Delangis et al. on May 16, 1995; U.S. Pat. No. 5,417,296 to Murdock on May 23, 1995; U.S. Pat. No. 5,421,423 to Huffstutler on Jun. 16, 1995; U.S. Pat. No. 5,425,288 to Evans on Jun. 20, 1995; U.S. Pat. No. 5,433,279 to Tessari et al. on Jul. 18, 1995; U.S. Pat. No. 5,441,119 to Head on Aug. 15, 1995; U.S. Pat. No. 5,442,979 to Hsu on Aug. 22, 1995; U.S. Pat. No. 5,449,047 to Schivley, Jr. on Sep. 12, 1995; U.S. Pat. No. 5,452,971 to Nevills on Sep. 26, 1995; U.S. Pat. No. 5,458,210 to Sollami on Oct. 17, 1995; U.S. Pat. No. 5,469,926 to Lessard on Nov. 28, 1995; and U.S. Pat. No. 5,474,139 to Odendahl et al. on Dec. 12, 1995. 
     Some examples of tool holders and related components which may possibly be utilized or adapted for use in the context of the present invention may be disclosed in the following U.S. Pat. No. 5,378,091 to Nakamura on Jan. 3, 1995; U.S. Pat. No. 5,382,122 to Mihic on Jan. 17, 1995; U.S. Pat. No. 5,388,487 to Danielsen on Feb. 14, 1995; U.S. Pat. No. 5,388,936 to Mihic on Feb. 14, 1995; U.S. Pat. No. 5,391,027 to Green on Feb. 21, 1995; U.S. Pat. No. 5,417,131 to Robertson on May 23, 1995; U.S. Pat. No. 5,427,484 to Galli on Jun. 27, 1995; and U.S. Pat. No. 5,460,066 to Dennstedt on Oct. 24, 1995. 
     Some examples of lubricants which may possibly be utilized or adapted for use in the context of the present invention may be disclosed in the following U.S. Pat. No. 5,378,379 to Bershas on Jan. 3, 1995; U.S. Pat. No. 5,388,631 to Suganuma et al. on Feb. 14, 1995; U.S. Pat. No. 5,399,274 to Marcus on Mar. 21, 1995; U.S. Pat. No. 5,415,791 to Chou et al. on May 16, 1995; U.S. Pat. No. 5,417,869 to Giacobbe et al. on May 23, 1995; U.S. Pat. No. 5,419,413 to Nakata et al. on May 30, 1995; U.S. Pat. No. 5,427,698 to Hirokawa et al. on Jun. 27, 1995; and U.S. Pat. No. 5,477,934 to Strand on Dec. 26, 1995. 
     Some examples of porous storage media which may possibly be utilized or adapted for use in the context of the present invention may be disclosed in the following U.S. Pat. No. 5,242,111 to Nakoneczny on Sep. 7, 1993; U.S. Pat. No. 5,362,167 to Loftin on Nov. 8, 1994; U.S. Pat. No. 5,384,264 to Chen et al. on Jan. 24, 1995; U.S. Pat. No. 5,433,545 to Keil on Jul. 18, 1995; U.S. Pat. No. 5,445,746 to Lee on Aug. 29, 1995; and U.S. Pat. No. 5,470,904 to Loftin et al. on Nov. 28, 1995. 
     The following U.S. patent applications Ser. No. 08/836,326 having inventor Ulrich Krenzer filed on May 9, 1997; Ser. No. 08/849,518 having inventor Ulrich Krenzer filed on Jun. 9, 1997; and Ser. No. 08/836,144 having inventor Ulrich Krenzer filed on Jun. 9, 1997 are hereby incorporated by reference as if set forth in its entirety herein. 
     U.S. patent application Ser. No. 09/005,271, filed on Jan. 9, 1998, having inventors Dirk Kammermeier and Bernhard Borschert, having the title “Drill with Cooling-Lubricant Channel” and claiming priority from Federal Republic of Germany Patent Application No. 295 11 430.4, filed on Jul. 14, 1995, Federal Republic of Germany Patent Application No. 295 12 745.7, filed on Aug. 8, 1995, Federal Republic of Germany Patent Application No. 296 02 997.1, filed on Feb. 21, 1996, and International Application No. PCT/EP96/03083, filed on Jul. 13, 1996, is hereby incorporated by reference as if set forth in its entirety herein. 
     The components disclosed in the various publications, disclosed or incorporated by reference herein, may be used in the embodiments of the present invention, as well as, equivalents thereof. 
     The appended drawings in their entirety, including all dimensions, proportions and/or shapes in at least one embodiment of the invention, are accurate and to scale and are hereby included by reference into this specification. 
     All, or substantially all, of the components and methods of the various embodiments may be used with at least one embodiment or all of the embodiments, if more than one embodiment is described herein. 
     All of the patents, patent applications and publications recited herein, and in the Declaration attached hereto, are hereby incorporated by reference as if set forth in their entirety herein. 
     The corresponding foreign and international patent publication applications, namely, Federal Republic of Germany Patent Application No. 295 12 745.7, filed on Aug. 8, 1995, and 296 02 997.1, filed on Feb. 21, 1996, having inventors Dirk Kammermeier and Bernhard Borschert, and DE-OS 295 12 745.7, filed on Aug. 8, 1995, and 296 02 997.1, filed on Feb. 21, 1996 and DE-PS 295 12 745.7, filed on Aug. 8, 1995, and 296 02 997.1, filed on Feb. 21, 1996 and International Application No. PCT/EP96/03489, filed on Aug. 7, 1996, and published as WO 97/05987 on Feb. 20, 1997, as well as their published equivalents, and other equivalents or corresponding applications, if any, in corresponding cases in the Federal Republic of Germany and elsewhere, and the references cited in any of the documents cited herein, are hereby incorporated by reference as if set forth in their entirety herein. 
     The details in the patents, patent applications and publications may be considered to be incorporable, at applicant&#39;s option, into the claims during prosecution as further limitations in the claims to patentably distinguish any amended claims from any applied prior art. 
     Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clause are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. 
     The invention as described hereinabove in the context of the preferred embodiments is not to be taken as limited to all of the provided details thereof, since modifications and variations thereof may be made without departing from the spirit and scope of the invention.