WO1998055254A1

WO1998055254A1 - Tool holder with integral coolant passage and replaceable nozzle

Info

Publication number: WO1998055254A1
Application number: PCT/US1998/011233
Authority: WO
Inventors: Gregory S. Antoun
Original assignee: Antoun Gregory S
Priority date: 1997-06-05
Filing date: 1998-06-02
Publication date: 1998-12-10
Also published as: AU7716098A

Abstract

A tool holder (10) for holding cutting inserts (20) for machine tool work includes at least one integral cooling passage (34) therethrough. Various coolant nozzles (50) are interchangeably installable in the holder (10), to provide different amounts of coolant fluid flow depending upon the specific work being accomplished. The nozzles (50) each incorporate a non-circular, preferably triangular, coolant outlet tip (62), which cross-sectional shape blends smoothly with the circular cross-sectional shape of the nozzle inlet (60) and passage through the tool holder. The triangular cross section of the latter portion and outlet of the nozzle passage precludes any significant circumferential flow vector of fluid flowing therethrough and flattens the sides of the fluid stream, thus precluding any significant pressure drop along the sides of the stream or expansion due to centrifugal reaction which would tend to pull the stream apart.

Description

TOOL HOLDER WITH INTEGRAL COOLANT PASSAGE AND REPLACEABLE NOZZLE BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION The present invention relates generally to tools used for cutting and machining, and more specifically to various embodiments of a tool or insert holder having an integral coolant passage therewith. The holder may be adapted for stationary machining of a moving workpiece (e. g., lathe work), or may be adapted for rotary machining of a relatively stationary workpiece (e. g. , milling) . The tool holder includes one or more replaceable cooling nozzles each having a novel coolant passage therethrough, which provides essentially laminar flow of coolant therethrough and precludes significant expansion of the coolant stream after it leaves the nozzle outlet, thereby providing greater chip breaking force and a greater volume of fluid contact with the cutting insert and workpiece to provide greater heat transfer.

2. DESCRIPTION OF THE RELATED ART

It is well known in the art of machining and cutting material, particularly metal, that the provision of some form of fluid (e.g., a light cutting oil of some sort) greatly prolongs the life of the cutting bit or insert between sharpenings, and also greatly speeds the cutting or machining of the material, by reducing friction and assisting in heat transfer from the working edge of the tool.

Accordingly, the practice of using such cutting fluid has been known for many years, and various cutting tool holders adapted for use with powered machine tools also have provision for the attachment of passages and/or nozzles for delivering a stream of cutting fluid to the cutting edge of the tool or tool insert. However, most such tool holders rely on cutting fluid to the cutting edge of the tool or tool insert. However, most such tool holders rely on clamps or similar arrangements to secure the nozzle to the tool holder, which procedure can result in misalignment of the nozzle with the cutting edge of the cutting insert, resulting in relatively little cutting fluid reaching the most critical point where it is needed.

Even where the nozzle is aimed relatively precisely, the fluid flow generally breaks up and forms more of a spray, rather than a cohesive liquid stream, as is desired. This is primarily due to the turbulent flow through conventional nozzles in combination with the extremely high pressures often used to deliver such coolant fluid, along with the circumferential flow vector which accompanies the round interior cross sectional shape of conventional nozzles. The sudden pressure drop as the fluid leaves the nozzle, along with the centrifugal reaction of the fluid due to the circumferential flow vector, results in rapid breakup and expansion of the fluid stream. The resulting spray cannot deliver the force required to break up chips from the cutting or machining process, and cannot provide efficient heat transfer. To this point, the solution has been to use ever increasing volumes and pressures of fluid, in an attempt to get sufficient fluid to the cutting tool edge to provide the desired chip breaking and cutting edge cooling actions . Accordingly, a need will be seen for a tool holder which includes an integrated coolant passage therewith, with replaceable coolant nozzles to allow the machine operator to change nozzles having different size orifices according to the needs of the specific job. The various nozzles have an axial flow which is automatically aligned with the cutting edge of the tool insert for optimum efficiency. The nozzles also include a novel interior passage shape to provide cohesive fluid flow for the coolant after it leaves the nozzle. The present tool holder may be adapted for stationary use against a rotating workpiece, as in a lathe, or may comprise a rotating tool holder for use against a relatively stationary workpiece, as in a milling machine. A discussion of the related art known to the present inventor, and its differences and distinctions from the present invention, is provided below.

U. S. Patent No. 3,741,049 issued on June 26, 1973 to George B. /Anderson, titled "Cutting Tool," describes a tool comprising a cutting bit or insert holder which in turn comprises a tool cartridge, a tool block, and a filler block for locating the tool cartridge on the tool block. A coolant fluid passage is provided through the tool block, but the coolant nozzle is not connected directly to this passage. Rather, the nozzle extends from the filler block, which has a passage therethrough which communicates with the tool block coolant passage. In any case, Anderson does not disclose any particular internal passage shape for the nozzle outlet, and discloses an elbow directing flow radially from the filler block passage.

U. S. Patent No. 4,795,292 issued on January 3, 1989 to Leonard Dye, titled "Chuck For Rotary Metal Cutting Tool," describes a chuck adapted for the installation of a single drilling or cutting bit concentrically therein. The chuck has a concentric coolant passage from the spindle to the bit insertion passage, with radial coolant passages formed above the bit insertion passage and further parallel or converging coolant passages extending toward the bit from the radial passages. Dye does not disclose the axial flow coolant nozzles or a multiple cutting insert head including coolant passages therethrough for his rotary chuck, as provided by the present invention. In the present rotary tool embodiment, the coolant fluid flows to the cutting head through a concentric central passage, either from the spindle attachment end or by means of converging DIN type coolant induction passages extending from the lower end of the spindle through the adapter to the central passage. Dye does not provide such a coolant passage arrangement, but sends all coolant through the central concentric passage to multiple ports which do not precisely align with a corresponding number of cutting inserts, as provided in the present tool .

U. S. Patent No. 4,848,198 issued on July 18, 1989 to Harold J. Royal et al . , titled "Chip Breaking Tool Holder, " describes a cutting insert clamp and main tool holder body. The clamp and body each have a coolant passage therethrough, with the two passages communicating with one another. While the Royal et al . coolant passage succeeds in directing the fluid flow directly toward the cutting edge of the insert, the connection between the passages of the two components is complex and requires a sophisticated seal. Moreover, this assembly must be loosened each time a cutting insert is changed or repositioned in the holder, thus increasing the chances of leakage. Royal et al . do not disclose any particular cross sectional shape for the internal passage of their nozzle.

U. S. Patent No. 5,148,728 issued on September 22, 1992 to Marian Mazurkiewicz, titled "High Pressure Lubricooling Machining Of Metals, " describes a cutting tool having at least one integral coolant passage therethrough, with the passage outlet aimed at the interface between the workpiece and the cutting edge of the tool. No means is disclosed for removing or replacing a coolant nozzle, nor is any specialized internal shape for the nozzle disclosed, as provided by the present invention. Mazurkiewicz in fact discloses a diverging coolant spray from his coolant nozzle, whereas the present coolant nozzles provide a highly coherent stream for more efficient cooling and breaking up of chips during the machining operation. Also, Mazurkiewicz discloses a relatively shallow angle between the axis of the coolant spray and the face of the cutting tool, in comparison to the present invention. U. S. Patent No. 5,272,945 issued on December 28,

1993 to Thomas A. Lockard, titled "Toolholder Assembly And Method, " describes an assembly wherein the coolant nozzle comprises a threaded bolt having a hollow center and partially cross drilled head, thereby forming a passage through the bolt with a radial outlet . The bolt is threaded into a mating passage in the tool block. The threaded configuration of the assembly allows the coolant nozzle bolt to be turned to direct the coolant flow as desired, but also allows for the inadvertent misalignment of the flow with the cutting edge of the insert. The axial outlet of the present nozzle precludes any possibility of misalignment. Also, Lockard discloses only a circular internal cross section for his coolant nozzle passage, unlike the non-circular configuration of the present coolant passage nozzle outlet.

U. S. Patent No. 5,290,135 issued on March 1, 1994 to Robert J. Ball et al . , titled "Rotary Ring Cutter Having Coolant Distribution And Discharge Means," describes a face mill cutting tool with coolant passages integrated with the cutting teeth or blades of the tool. All of the blades are formed as a homogeneous unit, and cannot be separated for individual replacement, as in the cutting inserts of the present tool. Moreover, the coolant passages are formed integrally within the cutting teeth or blades, and cannot be replaced individually, as can the coolant nozzles of the present invention. Ball et al . do not disclose any concentric coolant supply, as provided in at least one embodiment of the present invention. U. S. Patent No. 5,340,242 issued on August 23, 1994 to William D. Armbrust et al . , titled "Chip-Breaking Toolholder With Adjustable Orifice Cap, " describes a toolholder body including a coolant passage therethrough, but the fluid is further routed through a separate block having a coolant nozzle outlet therein. A hollow bolt secures the coolant nozzle block to the toolholder body, with fluid passing through the bolt and radially outward from a lateral passage below the head of the bolt, which communicates with the coolant nozzle block. The result is a complex assembly, requiring a plurality of seals as well as including an additional eccentrically headed bolt acting as a cam for adjustment of the coolant passage block. Figure 2 of the Armbrust et al . patent makes clear the problem of coolant stream breakup which is solved by the present invention, but Armbrust et al . do not disclose any particular outlet shape for their coolant nozzle to address this problem.

U. S. Patent No. 5,346,335 issued on September 13, 1994 to Jacob Harpaz et al . , titled "Metal Cutting Tool," describes a tool having a cutting insert with a coolant passage extending therethrough. The coolant passage communicates with a fluid passage in the tool holder block. Harpaz et al . require a specialized cutting insert for use with their tool; the cutting insert would be costly to produce, due to the forming of the coolant passage through the hardened material of the insert. Moreover, Harpaz et al . are silent regarding any cooling passage internal shape other than circular for their cutting tool.

U. S. Patent No. 5,388,487 issued on February 14, 1995 to Jan Danielsen, titled "Hydraulic Tool Holder With Coolant Jets," describes locking means for securing the tool holder in place by highly pressurizing the holder to expand its circumference to grip the mating component. Danielsen also discloses adjustable coolant nozzles which may be focused toward the interface between the cutting tool or insert and the workpiece. However, Danielsen is silent regarding any particular nozzle configuration to provide a coherent stream of coolant, as provided by the present invention. Moreover, due to the means used to secure the Danielsen holder in place, coolant cannot be provided concentrically down the center of the tool axis in order to simplify the coolant flow routing.

U. S. Patent No. 5,402,696 issued on April 4, 1995 to Gil Hecht et al . , titled "Seal Insert For The Shaft For A Workpiece, " describes a device comprising a threaded insert which fits between a threaded coolant duct nipple and the unthreaded end of a tool holder adaptor. The device acts as a connector between the coolant nipple and the adaptor in cases where the adaptor does not have a mating threaded end to fit the nipple (e. g., where the adaptor has been shortened by cutting off the threaded end) . No disclosure is made of any coolant nozzle configuration or orientation, although Hecht et al . mention the coolant flowing from apertures "so as to be sprayed on to the work piece..." (column 3, lines 53 - 54). Thus, Hecht et al . recognize the problem of the coolant flow dissipating as a spray, rather than being concentrated as a cohesive stream, but offer no solution to the problem.

U. S. Patent No. 5,405,155 issued on April 11, 1995 to Roger J. Kanaan et al . , titled "Sealing Collet," describes a collet for a drill bit or the like having resilient means for sealing the collet to permit the passage of coolant therethrough to outlets for spraying the coolant toward the tip of the tool bit. As the locking collet for holding the bit takes up the center of the device, the fluid flow is through a generally concentric cylindrical chamber around the center of the device, rather than being disposed centrally through the tooling, as in at least one embodiment of the present rotary tool. No radially symmetrical, multiple bit rotary cutting tool is disclosed by Kanaan et al . , as provided by the present invention. Also, Kanaan et al . indicate a divergent spray of coolant from their coolant nozzles (Figure 5) , rather than a coherent liquid stream, as in the present invention.

U. S. Patent No. 5,439,327 issued on August 8, 1995 to Raphael Wertheim, titled "Metal Cutting Tool, " describes a cutting insert holder including at least one coolant passage which terminates at an external edge adjacent at least one face of the cutting insert. The inserts are specially formed with at least one external coolant channel formed between the coolant passage outlet of the tool holder and the working edge of the insert. The specially formed inserts are thus relatively difficult and costly to manufacture, as in the case of the inserts of the '335 patent to Harpaz et al (Wertheim being a co-inventor) , discussed further above. No mention is made by Wertheim of any particular cross sectional shape of the interior of the coolant passage in the tool holder block.

U. S. Patent No. 5,503,913 issued on April 2, 1996 to Udo Konig et al., titled "Tool With Wear-Resistant Cutting Edge Made of Cubic Boron Nitride Or Polycrystalline Cubic Boron Nitride, A Method Of Manufacturing The Tool And Its Use, " describes an oxide coating process for such tools to increase their wear resistance. While such cutting inserts could be used with the present tooling, Konig et al . restrict their disclosure to the specifics of such oxide coated cutting inserts or tools, and are silent regarding any cooling means, nozzles, or other novel features of the present invention.

U. S. Patent No. 5,545,490 issued on August 13, 1996 to Takatoshi Oshika, titled "Surface Coated Cutting Tool," describes a titanium compound coating process for cutting inserts or tools. As such, the disclosure is similar to that of the Konig et al . '913 U. S. Patent discussed immediately above, with no disclosure of any cooling nozzles or other cooling means, either for stationary or rotating tooling, as provided by the present invention.

British Patent Publication No. 795,729 published on May 28, 1958, titled "Improvements In Cutting Tools For Lathes," describes a cutting tip which is brazed or cemented to the tool insert, the insert in turn being bolted to the tool holder. The tool holder and insert are adapted to provide a jet of carbon dioxide

(rather than a cooling oil or other liquid) terminating in a plurality of fine channels (rather than a single liquid outlet) "which are directed away from the cutting tip of the tool..." (page 2, column 1, lines 32 - 33) rather than toward the cutting tip, as provided by the present invention. The disclosure also teaches the direction of the gas away from the chips being cut, in order to avoid cooling the chips. This teaches away from the present invention, in which the coolant is directed at the cutting tip of the insert, and thus at chips as they are being cut. The shock cooling action on the chips assists in breaking up the chips, which is considered desirable.

French Patent Publication No. 2,422,468 published on November 9, 1979 illustrates a ream having a plurality of cutting inserts disposed about the body thereof . Each of the cutting inserts has a coolant nozzle disposed immediately forwardly thereof in the direction of cutting rotation of the ream, but the nozzles are each angled away from the cutting edge of the insert, rather than toward the insert cutting edge, as in the present invention. Figure 1 of the French Patent Publication clearly shows the buildup of a curled chip in front of the cutting insert, which blocks the coolant and lubricant flow from the nozzle outlet disposed forwardly thereof.

German Patent Publication No. 3,105,933 published on August 19, 1982 illustrates a rotary tool having a plurality of cutting edges, each with a coolant nozzle projecting forwardly therefrom in the direction of rotation. The nozzles are integral with their respective cutting elements or inserts, and cannot be removed separately therefrom, as in the present invention. Figure 2 clearly indicates a widening of the coolant spray pattern, rather than a cohesive liquid coolant stream, as provided by the coolant nozzles of the present invention.

Soviet Patent Publication No. 1,230,799 published on May 15, 1986 illustrates a water cooling system for tipped lathe tools wherein at least the tool block and insert holder include coolant passages therethrough. The insert holder includes a plurality of relatively small passages, to distribute the coolant over the face of the cutting insert. The assembly includes a compensating plate for retaining the coolant until it reaches a sufficiently high temperature to vaporize, whereupon the coolant flows from the outlets of the insert holder as steam. The liquid coolant used with the present invention is not heated to such a degree, as it is separated from the cutting tip before being ejected from the outlet nozzle extending from the tool block. As in the case of the related art discussed above, the Soviet patent makes no disclosure of other than circular or semicircular internal shapes for the coolant passages.

Finally, British Patent Publication No. 2,212,078 published on July 19, 1989, titled "Cutting Tool With Cutting Fluid Channel," describes a tool having a coolant channel disposed along the outer surface of the tool . This teaches away from the internal passage of the present tool holder, and cannot direct a stream of fluid under high pressure as provided by the present invention.

None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. SUMMARY OF THE INVENTION

The present invention comprises a tool holder having at least one integral coolant passage and nozzle for ejecting a cohesive stream of liquid coolant directly toward the tip of the corresponding cutting insert secured by the tool holder. The nozzle is easily replaceable and interchangeable for nozzles having different outlet dimensions for different types of work. The nozzles each have a novel cross section to provide cohesive and substantially laminar flow of the coolant after it leaves the nozzle, thus providing a concentrated stream of liquid to the cutting edge of the insert secured in the present tool holder, as opposed to a divergent spray as provided by coolant nozzles of the prior art. The nozzle outlet essentially eliminates any circumferential flow vector therein, greatly reducing centrifugal effect which causes typical streams to break up and expand. The present invention is applied to relatively stationary machining tools, i. e., tool holders for use in lathes and the like, and also to rotary tools, i. e., cutting heads for milling machines and the like. It will be seen that the rotary cutting tool embodiments may also be applied to live tooling for lathes and the like, as well . BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a front perspective view of a first embodiment of the present invention showing a relatively stationary tool holder and its general features .

Figure 2 is a perspective view in section of a coolant nozzle used with the present tool holder embodiments .

Figure 3 is a front or outlet end elevation view of the coolant nozzle of Figure 2.

Figure 4 is a rear or inlet end elevation view of the coolant nozzle of Figure 2. Figure 5 is an elevation view in partial section of a rotary tool holder or cutting head assembly for use in a milling machine or the like, showing details of the fluid passages therethrough.

Figure 6 is an elevation view in section of another embodiment of a rotary cutting head incorporating the present coolant nozzles. Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises various embodiments of a tool holder for holding one or more cutting inserts for use with machine tools in machining operations. Such machine tools are almost universally provided with some form of coolant means for supplying a liquid coolant to the interface between the cutting edge of the insert and the workpiece being machined. The present tool holder in its various embodiments includes an integral coolant passage therethrough, with one or more replaceable coolant nozzles which provide significant improvements in controlling and directing the flow of a liquid stream of coolant to the cutting edge of the insert (s) .

Figure 1 provides a perspective view of a first embodiment of the present tool holder, designated by the reference numeral 10. The holder 10 comprises an elongate unitary, monolithic and generally rectangular block of hard metal, having a solid rectangular mounting end 12 providing for securing the holder 10 removably to a stationary holding fixture on a machine tool, and an opposite cutting insert attachment end 14. The cutting insert attachment end 14 has a first or cutting insert corner 16 with a cutting insert recess 18 formed therein. This insert recess 18 is configured to accept a cutting insert 20, perhaps with a spacer 22, removably therein. (While a rectangular recess 18 and corresponding insert 20 are shown, it will be understood that the present tool holder 10 may be configured to accept a wide variety of insert shapes and configurations, and is not limited only to a rectangular insert 20 as shown in Figure 1.) The insert 20, and spacer 22, are removably secured within the recess 18 by an insert bolt 24 and a finger clamp 26 which is threadedly secured to the holder 10 by a clamp bolt 28.

The insert attachment end 14 of the holder 10 has a truncated second corner 30, generally laterally opposite the first or insert attachment corner 16, with a coolant passage block 32 extending therefrom. The coolant passage block 32 is formed integrally and monolithically with the remainder of the tool holder block 10, as a single unit. A coolant passage 34 is provided through the block 32, with the coolant passage 34 having an inlet end 36 and opposite outlet end 38.

The inlet end 36 of the coolant passage 34 includes a coolant line attachment fitting 40 extending therefrom, with the inlet end 36 being formed to position the attached fitting 40 conveniently for attachment to a conventional external coolant line

(not shown) . However, the opposite outlet end 38 of the coolant passage 34 is oriented to be axially aligned at least generally with the cutting edge or corner 42 of the cutting insert 20 which has been secured to the holder 10. This configuration of the coolant passage 34 may result in a bend or angle somewhere in the passage 34, but it will be seen that the outlet end 38, and portion of the passage 34 at least immediately upstream therefrom, is axially aligned with the cutting edge or corner 42 of the insert 20, to provide smooth and efficient coolant fluid flow.

The outlet end 38 of the coolant passage 34 includes a coolant nozzle 50 which is removably installed within the passage outlet end 38, as by the threaded portion 52 of the nozzle 50 which mates with a conventionally internally threaded portion of the coolant passage outlet end 38. Details of the coolant nozzle 50 are shown in Figures 2 through 4. The coolant nozzle 50 is formed as a unitary, monolithic component, of a relatively hard metal in order to withstand the high fluid pressures which may be applied to the device. The nozzle 50 includes an inlet end 54 which fits closely into the outlet end 38 of the nozzle block coolant passage 34, and an opposite nozzle outlet end 56, which is generally aligned with the insert cutting corner or edge 42 when the nozzle 50 is installed in the coolant passage outlet end 38 of the block 10.

The coolant nozzle 50 is essentially in the form of a straight cylindrical tube, with coolant passing through a straight, axial coolant passage 58 which extends from the nozzle inlet end 54 to the opposite nozzle outlet end 56. The passage 58 has a relatively large diameter, cylindrical cross section shape at its inlet end portion 60, but the opposite outlet end portion 62 has a considerably smaller cross sectional area in order to direct the coolant fluid in a tightly controlled stream to the insert cutting edge 42 and its interface with a workpiece during machining operations . It will be seen that the outlet end portion 62 of the coolant nozzle 50 has a non-circular cross section, preferably of a polygonal configuration. More specifically, the nozzle outlet end portion 62 comprises a triangular cross section, although other non-circular or polygonal sections (rectangular, etc.) might also be found to provide the desired control of the coolant stream, depending upon the flow and velocity of the coolant as it passes through and leaves the nozzle. The polygonal shape of the nozzle outlet end portion 62 is blended smoothly into the larger diameter of the circular shape of the nozzle outlet end portion 60, as shown in the nozzle cross section of Figure 2. This may be accomplished by means of a suitable machining process (e. g., wire EDM process) . It is critical that the nozzle passage 58 have a smooth and continuous change in cross sectional shape which is devoid of lateral edges from the inlet end 54 to the opposite outlet end 56 of the nozzle 50, to provide the desired coolant flow characteristics.

Conventional coolant systems have been found to impart at least some turbulence to the coolant as it flows through the coolant passages, particularly through the coolant nozzle itself. This is due to "steps" or lateral edges protruding into the coolant nozzle passage as the bore of the passage decreases from a large diameter at the inlet end to a smaller diameter at the outlet end, and other factors, such as sharp bends as the fluid transitions from axial flow through the nozzle body to radial flow through a radially disposed outlet passage. This turbulence leads to the breakup of the coolant stream as it exits the outlet end of such a conventional nozzle, causing the coolant stream to widen into a spray pattern rather than retaining its cohesiveness as a liquid stream. Such a coolant spray cannot provide the physical force required to break up metal chips as they are cut from the workpiece during machining operations, and moreover cannot provide sufficient fluid mass to carry away heat efficiently. The present nozzle 50 obviates these turbulence inducing obstructions by means of the straight axial passage 58 which is aligned axially with the coolant passage 34 through the block 32 of the holder block 10, and the smooth transition from the inlet end 54 to the outlet end 56 of the nozzle 50. Another problem with conventional coolant delivery systems is that the coolant fluid will almost always have some non-axial component of flow induced to the coolant stream within the lines and coolant nozzle, due to curves in the lines, non-axial bends in the passages, and/or various misaligned internal obstructions. Such non-axial flow produces a component of circumferential flow to the fluid, which imparts a centrifugal reaction to the circumferential fluid flow. This, along with the turbulent flow discussed above, causes the fluid flow to expand suddenly upon departing the outlet end of the nozzle, thereby producing a relatively wide spray of fluid and vapor, rather than a coherent fluid stream, as is desired. The present nozzle provides substantial laminar flow through the interior thereof, due to the smooth internal passage walls which are devoid of edges and obstructions. Also, the polygonal cross sectional shape of the passage walls near the outlet end of the nozzle, cause the fluid to follow the longitudinal lines of the passage defined by the flat walls and apices of the triangular nozzle outlet cross section. Any non-linear flow vector of the coolant is essentially eliminated by the time the fluid reaches the outlet end 56 of the present nozzle 50, thus eliminating any centrifugal effect which would otherwise cause the fluid to spread upon leaving the outlet end 56 of the nozzle 50. The smooth, laminar flow provided by the present nozzle 50, along with the elimination of any circumferential flow due to the non-circular outlet portion of the nozzle 50, serve to retain a narrow and cohesive fluid stream as the coolant departs the outlet end 56 of the nozzle 50. This allows the fluid to impact chips with much greater force than would be provided by a spray, thereby breaking up chips more readily. The more concentrated mass of the fluid stream also absorbs more heat from the workpiece, insert, and chips.

It has been found that the sudden cooling of such chips as they are cut from the workpiece is an important factor in causing them to break away from the workpiece, and the present coolant nozzle 50 is of great assistance in providing a relatively large mass of coolant directed to the critical point, in order to provide the desired sudden cooling of chips as they are cut from the workpiece . It will be noted that the present coolant nozzle may be provided in virtually any practicable size, depending upon the desired volume of coolant flow and velocity at the nozzle outlet. For example, a coolant pressure of 2500 pounds per square inch will require a nozzle outlet end maximum width of about .081 inch in order to provide a flow of 8 gallons per minute. This results in a coolant fluid stream velocity of up to 500 miles per hour, thus delivering substantial impact forces for chip breakup, as well as providing a significant fluid volume in a concentrated stream for heat transfer. Other nozzle sizes may be provided, depending upon the coolant flow and velocity desired. Coolant flow may vary down to about 4 gallons per minute, and up to about 20 gallons per minute, with the width of the nozzle outlet varying accordingly. Nozzle outlet end widths from about .040 inch to about .12 inch have been found to provide suitable fluid flows and velocities, depending upon the specific machining operation being conducted. The present nozzle in any of its different size embodiments is interchangeable, so nozzles of different outlet sizes may be removed and replaced easily to adjust fluid flow as desired.

Figures 5 and 6 disclose further embodiments of the present invention, wherein the present nozzles 50 and means for delivering coolant thereto, are provided in a rotary tool holder body for machining a relatively stationary workpiece, as in a milling machine or the like. A first embodiment 100 of such a tool holder body assembly, is illustrated in Figure 5. The tool holder body 100 includes a mounting end 102, having a conically tapered spindle 104 extending upwardly therefrom for securing to a conventional rotary drive means (not shown) to rotate the tool for cutting or machining a relatively stationary workpiece. The mounting end 102 includes a concentric internally threaded upper passage 106, serving for securing the spindle portion 104 within a mating conical fitting in the drive means, but also serving as a concentric fluid passage for routing coolant and lubricant fluid to the cutting inserts secured to the cutting insert attachment end of the assembly, and discussed further below.

The lower portion of the mounting end 102 also includes a central, concentric passage 108 therethrough, which is internally threaded for securing the cutting insert attachment end or head of the assembly 100. This lower threaded passage 108 communicates with the upper threaded passage 106, to provide a concentric coolant and lubricant fluid passage therethrough. While the above upper and lower threaded passages

106 and 108 may serve to provide a fluid passage for cooling and lubricating the cutting action of the cutting inserts of the insert attachment end or head of the assembly 100, other means of delivering coolant and lubricant fluid to the insert attachment head may also be provided. The mounting end 102 of the assembly 100 of Figure 5 also includes a circumferential flange 110, with a plurality of coolant passages 112 passing through the mounting end 102 from the flange 110 inwardly to a fluid transfer chamber 114, which also serves to receive the cutting insert head. (This configuration is known as the DIN standard, and it will be seen that both fluid delivery means, i. e., concentric through the spindle 104 and DIN through the passages 112, would not normally be provided in a single unit. However, the DIN passages 112 could be machined into all such mounting ends 102, and plugged by conventional means, e.g., threaded plugs, etc., when not required.)

A cutting insert attachment end or head 120 is threadedly attachable to the lower threaded passage 108 of the mounting end 102, by means of an externally threaded shank 122. The head 120 is accurately secured to the mating mounting end 102 of the assembly 100 by means of a pilot 124 which fits accurately within a mating recess in the base of the mounting end 102, and a precisely machined face 126 which mates with the base of the mounting end 102. (It will be noted that clearances in Figure 5 are greatly exaggerated, for clarity in the drawing figure.) This face lock and pilot system provides an extremely accurate means of assuring that the axes of the two components 102 and 120 are precisely concentric, for accuracy in locating the cutting or machining plane of the head 120 and its cutting inserts.

The cutting insert attachment end or head 120 also includes a central, concentric fluid passage 128 extending through the center of the threaded shank portion 122. A plurality of radially disposed transfer passages 130 extend outwardly from the central fluid passage 128 to communicate with the transfer chamber 114 of the mounting end 102 when the insert attachment end 120 is secured thereto. Thus, when the cutting head 120 is secured to the mounting end 102 of the assembly 100, fluid may be provided to the central fluid passage 128 of the cutting head 120 by means of the DIN passages 112 extending downwardly and inwardly from the mounting portion flange 110, into the relief between the pilot portion 124 of the cutting head 120 and the threaded passage 108 of the mounting portion 102 defining the fluid transfer chamber 114, and thence through the radial transfer passages 130 to the fluid passage 128 of the cutting head 120. An O-ring seal 132 is provided at the beveled shoulder of the pilot 124, for sealing the fluid transfer chamber to preclude leakage past the pilot 124 and face 126 of the cutting insert attachment head 120. In the event that fluid is provided through the threaded upper passage 106 of the mounting portion 102, the fluid passes in a straight line from the upper passage 106 through the central fluid passage 128, which extends completely throughout the threaded shank portion 122 of the cutting head 120.

The lower portion of the cutting head attachment end 120 includes a series of evenly spaced recesses 134 formed therein, for the removable attachment of cutting inserts 136 thereto. It will be seen that any practicable number of such recesses 134 and a corresponding number of inserts 136 may be provided, not limited to the number of recesses and inserts indicated in the tools of Figures 5 and 6. Each of the reliefs or recesses 134 has a face disposed at an angle to the axis of the tool assembly 100, thereby providing a rake angle 138 for each of the cutting inserts 136. A series of coolant passages 140, corresponding to the number of cutting insert recesses 134 and inserts 136 of the cutting head 120, is provided for delivering fluid to the cutting inserts 136. Each passage 140 has an inlet end 142 which communicates with the central fluid passage 128, and an opposite outlet end providing for the installation of a coolant nozzle 50 therein, with the nozzle 50 of the rotary tool embodiments of Figures 5 and 6 being essentially identical to the nozzle 50 of the stationary tool embodiment of Figures 1 through 4 , i . e . , having a circular inlet section with a straight, smoothly tapering internal passage terminating in a smaller triangular or other polygonal outlet. The axis of each of the coolant passages 140 defines an intercept angle 144 to the rake angle 138 of the inserts 136, and is formed to align the corresponding coolant nozzle 50 with the outer cutting edge 146 of each of the cutting inserts 136. The rake angle 138 of the inserts 136 and intercept angle 144 of each corresponding coolant passage 140 defines an angle 148 preferably between ten and twenty five degrees.

Figure 6 provides a detailed elevation view in section of a cutting insert attachment end or head 120a, which will be seen to be similar to the head 120 of Figure 5, with the primary difference being the relatively wider lower portion extending from the threaded attachment shank 122a. Otherwise, the insert attachment head 120a of Figure 6 will be seen to be similar to the head 120 of Figure 5, having a central fluid passage 128a with radial transfer passages 130a for accepting fluid from the DIN type coolant fluid passages of the mounting end or portion 102 of the assembly, as shown in Figure 5. A plurality of reliefs or recesses 134a is provided about the lower circumference of the head 120a, for the removable attachment of cutting inserts 136a therein. The recesses 134a are disposed at an angle, to provide a rake angle 138a for the cutting inserts, in the manner of the cutting head 120 of Figure 5.

A plurality of coolant passages 140a is provided, corresponding to the number of cutting inserts 136a of the head 120a. Each of the passages 140a has an inlet end 142a communicating with the central fluid passage 128a and an opposite outlet end having a coolant nozzle 50 removably installed therein, in the manner of the cutting head 120 of Figure 5. The axis of each of the coolant passages 140a and their concentric nozzles 50 defines an intercept angle 144a with the outer cutting edge 146a of each corresponding insert, as in the cutting head 120 of Figure 5. The included angle 148a between the intercept angle 144a of the coolant passage and nozzle axis and the insert rake angle 138a is preferably between 10 and 25 degrees, in each cutting head embodiment .

In summary, the present tool holder in its various embodiments will be seen to provide a significant advance in the technology of cooling workpieces and cutting tips or inserts during machining operations. The coolant nozzle associated with the present tool holder provides significant improvements in the delivery of a cohesive stream of coolant fluid directly to the workpiece and insert interface, to provide optimum force for chip removal and also optimum fluid mass for maximum heat transfer from workpiece and insert to the coolant. The non-circular outlet of the present nozzle provides a novel means to eliminate various characteristics which lead to the breakup of the coolant stream in other nozzles of the related art. It will be seen that the present nozzle, while being shown with a tool holder for use in a relatively stationary position against a rotating workpiece, is also adaptable for use with rotating tool holders for use against a relatively stationary workpiece (mills, etc.) . In the interest of providing light weight to facilitate balancing such rotary tools, while still providing the strength required for such tools, at least the cutting insert attachment heads or ends of such tools may be formed of titanium. Other materials may of course be used, such as tool steel, etc. as desired. Thus, the present tool holder and nozzle will serve to advance the efficiency of machining operations in various environments. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

Claims

1. A tool holder for holding at least one cutting insert with a cutting edge for use with machine tools, comprising : a tool holder body with a mounting end for removably securing to a machine tool, and an opposite cutting insert attachment end; said cutting insert attachment end having at least one cutting insert recess formed therein for removably securing a cutting insert therein; said cutting insert attachment end further having at least one coolant passage formed therein for providing coolant flow to the cutting insert of a corresponding said at least one cutting insert recess; said at least one coolant passage having an inlet end and an opposite outlet end with said outlet end of said at least one coolant passage being axially aligned generally with the cutting edge of the cutting insert removably installed within the corresponding said at least one cutting insert recess; and at least one coolant nozzle for removably installing within said outlet end of said at least one coolant passage, with said at least one coolant nozzle having a straight coolant nozzle passage formed axially therethrough and axially aligned with the edge of the cutting insert of the corresponding said cutting insert recess when said coolant nozzle is removably installed in said outlet end of said coolant passage.

2. The tool holder according to claim 1, wherein said mounting end is a generally rectangular solid for fixed attachment to a stationary fixture for working a rotating workpiece.

3. The tool holder according to claim 1, wherein said tool holder body has a generally circular configuration for attachment to a rotating drive means for working a relatively fixed workpiece, with said tool holder body including a plurality of cutting insert recesses disposed therein.

4. The tool holder according to claim 1, wherein said coolant nozzle passage includes an inlet end having a circular internal cross section and an opposite outlet end having a polygonal internal cross section for said coolant nozzle passage, with said outlet end having a substantially smaller cross section than said inlet end.

5. The tool holder according to claim 4, wherein said outlet end of said coolant nozzle passage has a triangular cross section.

6. The tool holder according to claim 4, wherein said coolant nozzle passage is smoothly contoured and devoid of lateral edges between said inlet end and said outlet end thereof.

7. A tool holder for holding a cutting insert with a cutting edge for use with machine tools, comprising: a monolithic, elongate tool holder block having a mounting end for removably securing to a machine tool, and an opposite cutting insert attachment end; said cutting insert attachment end having a first corner with a cutting insert recess formed therein for removably securing a cutting insert therein; said cutting insert attachment end further having a second corner laterally opposite said first corner, with a coolant passage block extending from said second corner and formed integrally and monolithically with said tool holder block; said coolant passage block including a coolant passage extending therethrough; said coolant passage having an inlet end and an opposite outlet end with said outlet end of said coolant passage being axially aligned generally with the cutting edge of the cutting insert removably secured within said cutting insert recess; and at least one coolant nozzle for removably installing within said outlet end of said coolant passage, with said coolant nozzle having a straight coolant nozzle passage formed axially therethrough and axially aligned with the edge of the cutting insert when said coolant nozzle is installed in said outlet end of said coolant passage.

8. The toll holder according to claim 7, wherein said mounting end is configured for fixedly attaching to a stationary fixture for working a rotating workpiece;

9. The tool holder according to claim 7, wherein said mounting end is a generally rectangular solid for fixed attachment to a stationary fixture for working a rotating workpiece.

10. The tool holder according to claim 7, wherein said coolant nozzle passage includes an inlet end having a circular internal cross section and an opposite outlet end having a polygonal internal cross section for said coolant nozzle passage, with said outlet end having a substantially smaller cross section than said inlet end.

11. The tool holder according to claim 10, wherein said outlet end of said coolant nozzle passage has a triangular cross section.

12. The tool holder according to claim 10, wherein said coolant nozzle passage is smoothly contoured and devoid of lateral edges between said inlet end and said outlet end thereof.

13. A tool holder for holding a plurality of cutting inserts each having a cutting edge for use with machine tools, comprising: a tool holder body with a mounting end for removably securing to a machine tool, and an opposite cutting insert attachment end; said mounting end including a conically tapered spindle for removably installing in a rotating drive means for working a relatively fixed workpiece; said cutting insert attachment end having a plurality of cutting insert recesses formed therein, each for removably securing a cutting insert therein; said cutting insert attachment end further having a plurality of coolant passages formed therein, with each of said coolant passages corresponding to one of said cutting insert recesses for providing coolant flow to the cutting insert thereof; said plurality of coolant passages each having an inlet end and an opposite outlet end, with said outlet end of each of said coolant passages being axially aligned generally with the cutting edge of the cutting insert removably installed within the corresponding one of said cutting insert recesses; and a coolant nozzle for removably installing within said outlet end of each of said coolant passages, with each said coolant nozzle having a straight coolant nozzle passage formed axially therethrough and axially aligned with the edge of the cutting insert of the corresponding one of said cutting insert recesses when said coolant nozzle is removably installed in said outlet end of the corresponding one of said coolant passages.

14. The tool holder according to claim 13, wherein each said coolant nozzle includes an inlet end having a circular internal cross section and an opposite outlet end having a polygonal internal cross section for said second passage, with said outlet end having a substantially smaller cross section than said inlet end.

15. The tool holder according to claim 14, wherein said outlet end of each said coolant nozzle has a triangular cross section.

16. The tool holder according to claim 14, wherein each said coolant nozzle is smoothly contoured and devoid of lateral edges between said inlet end and said outlet end thereof.

17. The tool holder according to claim 13, wherein: said cutting insert attachment end includes a central, concentric fluid passage, with each of said coolant passages communicating with said central fluid passage; and said mounting end includes a central, concentric fluid passage communicating with said central fluid passage of said cutting insert attachment end, for providing fluid coolant flow from said mounting end to said cutting insert attachment end of said tool holder body.

18. The tool holder according to claim 13, wherein: said mounting end has a flange disposed below said spindle, a transfer chamber for receiving said cutting insert attachment end, and a plurality of fluid passages each passing through said mounting end from said flange to said transfer chamber; and said cutting insert attachment end includes a central, concentric fluid passage, with each of said coolant passages communicating with said central fluid passage, and a plurality of radially disposed transfer passages extending outwardly from said central fluid passage and communicating with said transfer chamber of said mounting end when said cutting insert attachment end is secured to said mounting end of said tool holder body, for passing coolant fluid through said fluid passages of said mounting end to said transfer chamber, thence through said transfer passages to said central fluid passage and said coolant passages of said cutting insert attachment end of said tool holder body.

19. The tool holder according to claim 13 with each of the cutting inserts having a face defining a rake angle, wherein each of said coolant passages and each said nozzle of said cutting insert attachment end has an axis, with the rake angle of a corresponding one of the cutting inserts and each said axis defining an included angle of between ten and twenty five degrees therebetween .

20. The tool holder according to claim 13, wherein at least said cutting insert attachment end is formed of titanium.

21. A tool holder for holding a cutting insert with a cutting edge for use with machine tools, comprising: an elongate tool holder block having a mounting end for removably securing to a machine tool, and an opposite cutting insert attachment end; said cutting insert attachment end having a first corner with a cutting insert recess formed therein for removably securing a cutting insert therein; said cutting insert attachment end further having a second corner laterally opposite said first corner, with a coolant passage block extending from said second corner and formed integrally and monolithically with said tool holder block; said coolant passage block including a coolant passage extending therethrough; said coolant passage having an inlet end and an opposite outlet end with said outlet end of said coolant passage being axially aligned generally with the cutting edge of the cutting insert removably secured within said cutting insert recess and including means for removably attaching a cooling nozzle thereto.

22. The tool holder according to claim 21, wherein said mounting end is a generally rectangular solid for fixed attachment to a stationary fixture for working a rotating workpiece.

23. The tool holder according to claim 21, including at least one coolant nozzle for removably installing within said outlet end of said coolant passage, with said coolant nozzle having a straight coolant nozzle passage formed axially therethrough and axially aligned with the edge of the cutting insert when said coolant nozzle is installed in said outlet end of said coolant passage.

24. The tool holder according to claim 23, wherein said coolant nozzle passage includes an inlet end having a circular internal cross section and an opposite outlet end having a polygonal internal cross section for said second passage, with said outlet end having a substantially smaller cross section than said inlet end.

25. The tool holder according to claim 24, wherein said outlet end of said coolant nozzle passage has a triangular cross section.

26. The tool holder according to claim 24, wherein said coolant nozzle passage is smoothly contoured and devoid of lateral edges between said inlet end and said outlet end thereof.

27. A coolant nozzle for a tool holder having a coolant passage with an inlet end and an opposite outlet end and providing for holding a cutting insert with a cutting edge for use with machine tools, comprising: a straight coolant nozzle body having an axially straight internal coolant nozzle passage therethrough; said coolant nozzle passage having an inlet end with a circular cross section, and an opposite outlet end with a polygonal cross section, with said outlet end having a substantially smaller cross section than said inlet end; said coolant nozzle body having an outlet end portion including an externally threaded portion thereon for removably installing within said outlet end of said coolant passage, and means for accepting a fastening tool for removably securing said coolant nozzle body within the outlet end of the coolant passage of the tool holder.

28. The coolant nozzle according to claim 27, wherein said outlet end of said coolant nozzle passage has a triangular cross section.

29. The coolant nozzle according to claim 28, wherein said coolant nozzle passage is smoothly contoured and devoid of lateral edges between said inlet end and said outlet end thereof.