Parting blade and blade holder configured for conveyance of pressurized coolant

Abstract

A cutting tool assembly includes a parting blade and a blade holder for holding same. The cutting tool assembly is configured for conveying pressurized coolant via the holder to a cutting portion of the parting blade. The blade holder includes a deceleration chamber configured for reducing the impact of the pressurized coolant against the parting blade.

Claims

1. A method of cooling a cutting edge (36) of a cutting insert (34), the method comprising: providing an elongated parting blade (14) having a parting blade body with unitary one-piece construction and comprising: a cutting portion (30) on which the cutting insert is mounted, a blade passageway (24) for conveyance of coolant from a blade inlet aperture (26) formed in a parting blade first side surface (50A) to a blade outlet aperture (28) of the cutting portion; mounting the parting blade (14) in a blade holder (12) having a holder connection surface (54) facing the parting blade (14), the blade holder (12) further having a holder inlet aperture (18) connected to a holder outlet aperture (20) via a holder passageway (16), with the blade inlet aperture (26) in fluid communication with the holder outlet aperture (20); wherein the cutting edge 36 is wider than at least a portion of the parting blade 14 which projects from the blade holder (12); and conveying coolant into the holder inlet aperture (16) at a pressure in excess of 20 bar, and through the holder passageway (16) such that a velocity of the coolant is decreased by the time it exits at the holder outlet aperture (20); and passing the coolant from the holder outlet aperture (20) to the blade inlet aperture (26), through the blade passageway (24) and out the blade outlet aperture (28) in a direction towards the cutting edge.

2. The method according to claim 1, comprising: conveying coolant into the holder inlet aperture (16) at a pressure in excess of 120 bar.

3. The method according to claim 1, comprising: connecting a coolant supply pipe to the holder inlet aperture (18), prior to conveying coolant into the holder inlet aperture (16).

4. The method according to claim 1, further comprising: providing a sealing element (52) which surrounds the holder outlet aperture (20), and sealingly engages parting blade's first side surface (50A) in which the blade inlet aperture (26) is formed.

5. The method according to claim 4, comprising: mounting the sealing element (52) in a sealing element recess (64) formed in the blade holder's holder connection surface (54) facing the parting blade's side surface (50A).

6. The method according to claim 5, comprising: mounting the sealing element (52) such that it projects sufficiently from the sealing element recess (64) to tilt the parting blade (14) from a parallel orientation relative to the holder connection surface (54).

7. The method according to claim 5, wherein the sealing element (52) has a cross sectional dimension (S.sub.D) larger than a recess channel distance (S.sub.RD), which is measurable between an outer peripheral surface (66) and an inner peripheral surface (68) thereof.

8. The method according to claim 1, comprising: passing the coolant above a rake surface (40) of the cutting insert, after the coolant exits the blade outlet aperture (28).

9. The method according to claim 1, wherein: the parting blade (14) has a second side surface (50B); the blade inlet aperture (26) opens out to both the first and second side surfaces (50A, 50B); the parting blade further comprises a sealing aperture (96); and the method further comprises: covering the second blade inlet aperture (26) by fastening a sealing device (56) to the sealing aperture (96), to thereby prevent coolant from exiting the second blade inlet aperture (26).

10. The method according to claim 4, wherein: the blade holder (12) is configured to allow sliding motion of a parting blade (14) relative to the blade holder (12); and mounting the parting blade (14) includes positioning the parting blade (14) with sliding movement restricted by the location of the sealing element and the parting blade.

11. The method of claim 1, wherein: the blade holder further comprises a blade seat (60) comprising a holder connection surface (54) and upper and lower longitudinal jaws (62A, 62B) disposed on opposing sides of the holder connection surface (54); the holder passageway (16) comprises a preceding portion (21) and a deceleration chamber (22) closer than the preceding portion (21) to the holder outlet aperture (20), and a transition region (88) at which the preceding portion (21) transforms into the deceleration chamber (22); in the preceding portion (21) at the transition region (88), the holder passageway (16) has a preceding portion cross-sectional area A.sub.P extending perpendicular to the coolant path, wherein: the holder connection surface (54) is formed with a sealing element recess (64) that surrounds the holder outlet aperture (20); a sealing element (52) is mounted in the sealing element recess (64); in the deceleration chamber (22) at the transition region (88), the holder passageway (16) has a deceleration chamber cross-sectional area (A.sub.D1) extending perpendicular to the coolant path, wherein: the deceleration chamber cross-sectional area is greater than the preceding portion cross-sectional area; and/or the deceleration chamber (22) comprises a barrier surface (90) facing the coolant path of the preceding portion (21) at the transition region (88).

12. The method according to claim 11, wherein the deceleration chamber cross-sectional area (A.sub.D1) is not greater than the preceding portion cross-sectional area (A.sub.P).

13. The method according to claim 1, wherein: the cutting portion (30) has an insert seat (32) configured to hold the cutting insert with resilient seat jaws.

14. The method according to claim 1, wherein the cutting edge (36) is wider than a width W.sub.B of the remainder of the parting blade (14).

15. A method of passing coolant under pressure through a cutting tool, comprising: providing an elongated parting blade (14) having a parting blade body with unitary one-piece construction and comprising: opposing first and second side surfaces (50A, 50B) extending between parallel first and second longitudinal mounting edges (92A, 92B) and between opposing first and second end edges (94A, 94B) which extend transverse to the longitudinal mounting edges; a cutting portion (30) which is associated with the first longitudinal mounting edge (92A) and the first end edge (94A), and comprising an insert seat (32); and a blade passageway (24) configured for being in fluid communication with a blade outlet aperture (28) and for conveyance of coolant, the blade passageway (24) extending from a blade inlet aperture (26) formed in at least one of the side surfaces to a blade outlet aperture (28) located at the cutting portion (30); supplying coolant to the blade inlet aperture (26) at a pressure in excess of 20 bar; and conveying the coolant through the blade passageway (24) and out the blade outlet aperture (28).

16. The method according to claim 15, wherein each of the first and second longitudinal mounting edges (92A, 92B) has a tapered shape with slanted surfaces for facilitating longitudinal sliding motion.

17. The method according to claim 15, wherein the blade inlet aperture (26) is closer to the second longitudinal mounting edge (92B) than to the first longitudinal mounting edge (92A); and the blade outlet aperture (28) is closer to the first longitudinal mounting edge (92A) than to the second longitudinal mounting edge (92B).

18. The method according to claim 17, wherein the insert seat (32) is configured to hold the cutting insert with resilient seat jaws.

19. The method according to claim 15, wherein the parting blade is configured to direct coolant toward a cutting edge (36), and adjacent to a rake face (38), of a cutting insert (34) retained by the parting blade.

20. The method according to claim 15, wherein said conveyance of coolant to the blade inlet aperture (16) is at a pressure of 120 bar or greater.

21. The method according to claim 15, wherein a width W.sub.Y of the blade passageway (24) is greater than 50% of a width W.sub.P of the parting blade (W.sub.Y>0.5 W.sub.P).

22. The method according to claim 15, wherein the blade outlet aperture (28) is located at a side of the insert seat that is connected to the first longitudinal mounting edge (92A).

23. The method according to claim 15, wherein the parting blade is symmetrical about a bisecting plane (P.sub.P) extending parallel with and equally spaced from the first and second side surfaces (50A, 50B).

24. The method according to claim 15, wherein: the parting blade is double-ended and has either: 180 degrees rotational symmetry about a blade axis (A.sub.B) that extends through the center of, and in a direction perpendicular to, the first and second side surfaces (50A, 50B), or mirror symmetry about a lateral plane (P3) extending perpendicular to the first and second side surfaces (50A, 50B) and located midway between the opposing first and second end edges (94A, 94B), and the parting blade is not rotationally symmetric about a blade axis that extends through the center of, and in a direction perpendicular to, the first and second side surfaces.

25. The method according to claim 15, wherein the parting blade further comprises a removable sealing device (56) for at least one sealing aperture formed in the parting blade, the sealing device (56) being configured to extend over and seal the blade inlet aperture to prevent cooling from exiting therefrom.

26. The method according to claim 19, wherein: the parting blade is seated in a blade holder (12); and the cutting edge (36) is wider than at least a portion of the parting blade 14 which projects from the blade holder (12).

27. The method according to claim 26, wherein the cutting edge (36) is wider than a width W.sub.B of the remainder of the parting blade (14).

28. A method of passing coolant under pressure through a cutting tool, comprising: providing a blade holder (12) comprising: a blade seat (60) comprising a holder connection surface (54) and upper and lower longitudinal jaws (62A, 62B) disposed on opposing sides of the holder connection surface (54), and a holder passageway (16) configured for conveyance of coolant and comprising a coolant path (42) extending therethrough from a holder inlet aperture (18) to a holder outlet aperture (20) formed at the holder connection surface (54); characterized in that: the holder passageway (16) comprises a preceding portion (21) and a deceleration chamber (22) closer than the preceding portion (21) to the holder outlet aperture (20), and a transition region (88) at which the preceding portion (21) transforms into the deceleration chamber (22); in the preceding portion (21) at the transition region (88), the holder passageway (16) has a preceding portion cross-sectional area (A.sub.P) extending perpendicular to the coolant path, wherein: the holder connection surface (54) is formed with a sealing element recess (64) that surrounds the holder outlet aperture (20); a sealing element (52) is mounted in the sealing element recess (64); in the deceleration chamber (22) at the transition region (88), the holder passageway (16) has a deceleration chamber cross-sectional area (A.sub.D1) extending perpendicular to the coolant path, wherein: the deceleration chamber cross-sectional area is greater than the preceding portion cross-sectional area; and/or the deceleration chamber (22) comprises a barrier surface (90) facing the coolant path of the preceding portion (21) at the transition region (88); supplying coolant to the holder inlet aperture (18) at a pressure in excess of 20 bar; and conveying the coolant through the holder passageway (16) and out the holder outlet aperture (20).

29. The method according to claim 28, wherein the blade holder (12) is configured to allow sliding motion of a parting blade (14) relative to the blade holder (12).

30. The method according to claim 28, wherein the sealing element (52) has a cross sectional dimension (S.sub.D) larger than a recess channel distance (S.sub.RD), which is measurable between an outer peripheral surface (66) and an inner peripheral surface (68) thereof.

31. The method according to claim 28, wherein the deceleration chamber cross-sectional area (A.sub.D1) is not greater than the preceding portion cross-sectional area (A.sub.P).

32. The method according to claim 28, wherein the pressure conveyed to the holder inlet aperture (18) is 120 bar or greater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:

(2) FIG. 1A is a perspective view of a cutting tool assembly including a blade holder, a parting blade, a cutting insert, and a sealing element;

(3) FIG. 1B is another perspective view of the cutting tool assembly of FIG. 1, with internal elements relating to the coolant path shown in broken lines;

(4) FIG. 1C is an end view of the cutting tool assembly of FIGS. 1A and 1B;

(5) FIG. 1D is the same end view as FIG. 1C schematically showing in broken lines the parting blade tilted from a parallel orientation relative to a holder connection surface of the blade holder;

(6) FIG. 2A is a side view of the parting blade in FIGS. 1A to 1C, with internal elements relating to the coolant path being shown;

(7) FIG. 2B is an end view of the parting blade in FIG. 2A;

(8) FIG. 2C is a plan view of the parting blade in FIGS. 2A and 2B;

(9) FIG. 3A is a side view of the blade holder in FIGS. 1A to 1C, excluding one of the longitudinal jaws and with some internal elements shown in broken lines;

(10) FIG. 3B is a cross section view taken along line 3B-3B in FIG. 3A;

(11) FIG. 3C is an enlarged view of an encircled portion in FIG. 3B, further including a sealing element mounted thereto; and

(12) FIG. 4 is an enlarged view of a similar portion of a blade holder to FIG. 3C, except with an alternative sealing arrangement.

DETAILED DESCRIPTION

(13) Reference is made to the figures, which illustrate a cutting tool assembly 10 configured for parting or slitting a metal workpiece (not shown) which will first be briefly described to provide a general understanding of the operation thereof.

(14) The cutting tool assembly 10 comprises a blade holder 12 and a parting blade 14 mounted thereon.

(15) The blade holder 12 comprises a holder passageway 16 for passage of coolant therethrough.

(16) The holder passageway 16 extends from a holder inlet aperture 18 to a holder outlet aperture 20, and comprises a preceding portion 21 and a deceleration chamber 22 that is closer than the preceding portion 21 to the holder outlet aperture 20. It will be understood that the preceding portion 21 and deceleration chamber 22 are configured relative to one another so that fluid entering the holder inlet aperture 18 decreases in velocity by the time it exits at the holder outlet aperture 20.

(17) The holder inlet aperture 18 is connectable to a coolant supply pipe (not shown), which in turn is connected to a coolant supply source (not shown). The cutting tool assembly 10 is configured, in this example, for conveyance of coolant at pressures of at least 20 bar, for example up to 120 bar. However, it will be understood that the subject matter of the present application could be configured for conveyance of coolant at even higher than 120 bar. It will also be understood that a cutting tool assembly or components thereof, which are configured to operate with coolant above a certain pressure threshold system (for example a threshold above 20 bar) could also work at pressures lower than such threshold, if desired.

(18) The holder outlet aperture 20 is in fluid communication with a blade passageway 24 of the parting blade 14.

(19) The blade passageway 24 extends from a blade inlet aperture 26 to a blade outlet aperture 28 located at a cutting portion 30 of the parting blade 14.

(20) The cutting portion 30 can comprise an insert seat 32, configured for receiving a cutting insert 34.

(21) The cutting insert 34 comprises a cutting edge 36 at an intersection of a rake surface 38, over which chips (not shown) from a cut workpiece (not shown) flow, and relief surface 40 thereof. As shown in FIG. 1C, the cutting edge 36 is wider than a width W.sub.B of a remainder of the parting blade 14, or at least the portion thereof that projects from the blade holder 12, for achieving slitting and/or parting operations.

(22) Drawing attention to FIGS. 3A to 3C, in operation, coolant (not shown) is conveyed to the holder inlet aperture 18, for example at a pressure of 120 bar, which follows a coolant path 42 defined by the holder passageway 16 and the blade passageway 24. For ease of description, the coolant path 42 is divided into a first path portion 42A defined by the holder passageway 16, and a second path portion 42B (FIGS. 1B and 2A) defined by the blade passageway 24.

(23) The holder passageway 16, and hence first path portion 42A, extends in a first direction, shown by the arrow designated as 44, and then, at a location generally designated by arrow 46, turns a certain amount, which in this non-limiting example is a quarter turn, and extends in a second direction, shown by the arrow designated as 48, and exits the holder outlet aperture 20.

(24) As coolant exits the holder outlet aperture 20, it impacts one of the blade side surfaces 50A, 50B of the parting blade 14, in particular the closer blade side surface 50A, and is contained within the boundaries of a sealing element 52 (FIG. 3C), which surrounds the holder outlet aperture 20 and sealingly engages the closer blade side surface 50A.

(25) Notably, the coolant decelerates upon reaching the deceleration chamber 22, thereby reducing the above-mentioned impact on the parting blade 14. It is understood that such impact applies a force on the parting blade 14 which, if great enough in magnitude, could space the proximal blade side surface 50A apart from an opposing holder connection surface 54, as well as the associated sealing element 52, and cause undesired leakage of the coolant. Accordingly, deceleration of the coolant in the deceleration chamber 22 is configured to reduce the force applied to the parting blade 14.

(26) After exiting the blade holder 12, the coolant follows the second path portion 42B, i.e. entering the blade inlet aperture 26, exiting the blade outlet aperture 28, passing above the rake surface 38 of the cutting insert 34 in a direction towards the cutting edge 36, for cooling the cutting edge 36 and/or the workpiece (not shown) being slit or parted.

(27) Components of the cutting tool assembly 10 will now be described in further detail to provide additional understanding of advantages thereof.

(28) Referring to FIGS. 1A to 1C and 3A, the blade holder 12 is elongated. It will be understood that such elongation can provide for, in an end view thereof (FIG. 1C) a compact design.

(29) To elaborate, as best shown in FIG. 1C, the blade holder 12 and sealing device 56 do not significantly protrude past the parting blade 14 in the direction of arrow 58. More specifically, in this example, the blade holder 12 protrudes past the parting blade 14, by a blade holder width W.sub.B, which has an equivalent magnitude as that of the parting blade width W.sub.P. The outermost projecting part of the cutting tool assembly 10 is the sealing device 56, which protrudes a width W.sub.SD from the blade holder 12 of corresponding magnitude to the parting blade width W.sub.P. To bring the widths into perspective, in the present example the sealing device protrudes 4.6 mm from the outermost surface 50B of the parting blade 14. For cutting tool assemblies 10 of similar construction, except with blades of different sizes, the parting blade width W.sub.P is the only expected, significantly varying width of those mentioned. Accordingly, the maximum lateral projection of the cutting tool assembly 10 from the outermost blade side surface 50B can be expected to be less than 5 mm. The width W.sub.Y (FIG. 2A) of the blade passageway 24 (which may be a diameter, when the blade passageway 24 has a circular cross-section) may be commensurate with the parting blade width W.sub.P. For example, in some embodiments, the width W.sub.Y of the blade passageway 24 may be greater than 50%, or even 64%, of the width W.sub.P of the parting blade (W.sub.Y>0.5 W.sub.P; W.sub.Y>0.64 W.sub.P). In some embodiments the width W.sub.Y of the blade passageway 24 may be less than 70% of the width W.sub.P of the parting blade (W.sub.Y<0.7 W.sub.P).

(30) It will be understood that a cutting tool assembly free of a protruding lateral projection can, in at least some applications, allow an increased lateral motion of the cutting tool assembly and hence cutting range thereof.

(31) The blade holder 12 further comprises a blade seat 60 configured for seating the parting blade 14. The blade seat 60 can comprise the holder connection surface 54 and first (lower) and second (upper) longitudinal jaws 62A, 62B disposed on opposing sides of the holder connection surface 54.

(32) The holder connection surface 54 can be planar to allow sliding motion of the parting blade 14 therealong. The holder connection surface 54 can further be formed with functional recesses. In particular, the holder connection surface can be formed with a sealing element recess 64 surrounding an associated holder outlet aperture 20. The holder connection surface 54 can also be formed with a cutting insert accommodation recess 166, for accommodating certain types of cutting inserts mounted on a parting blade. In this example, the cutting insert accommodation recess 166 has a U-shaped peripheral wall 168.

(33) The sealing element recess 64 can be elongated, for example oval-shaped. Such elongation can allow movement of the parting blade 14 whilst maintaining a coolant sealed construction. It will be understood that in consideration of space constraints of the holder connection surface 54, the sealing element recess 64 could be other regular shapes, non-regular shapes, or even non-elongated shapes such as a circle etc.

(34) One possible advantage of forming a sealing element recess on the holder connection surface 54 instead of on the parting blade 14 or, stated differently, having planar first and second side surfaces 50A, 50B of a parting blade 14, can be that the relatively thin elongated parting blades are not weakened.

(35) Drawing attention to FIG. 3C, the sealing element recess 64 can have an outer peripheral surface 66, an inner peripheral surface 68, and a base surface 70 connecting the outer and inner peripheral surfaces 66, 68.

(36) The sealing element 52 can be mounted in the sealing element recess 64. The sealing element 52 can have a corresponding shape to the sealing element recess 64, which in this example is oval-shaped. The sealing element 52 can be sized to be biased against the outer peripheral surface 66 and base surface 70 of the sealing element recess 64. The sealing element 52 can be sized to protrude from the holder connection surface 54, for contacting the parting blade 14. A gap 72, located between the sealing element 52 and one of the surfaces of the sealing element recess 64, which in this example is the inner peripheral surface 68, can allow for expansion of the sealing element 52 within the sealing element recess 64. Such gap 72 can possibly prevent undesired spacing of the parting blade 14 in a direction away from the blade holder 12.

(37) Defined between the inner peripheral surface 68 and the holder outlet aperture 20 is a holder outlet aperture wall 74. The holder outlet aperture wall 74 can protect the sealing element 52 from damaging pressurized coolant and/or direct coolant into the blade inlet aperture 26.

(38) FIG. 4 shows an alternative sealing arrangement on a blade holder designated as 12. Blade holder 12 differs from the previously described blade holder 12 in connection with the sealing arrangement. It has been found that the sealing arrangement in FIG. 4 can be particularly effective in reducing or preventing undesired ejection of a sealing element 52 thereof from an associated sealing element recess 64.

(39) In blade holder 12, the sealing element recess 64 comprises an outer peripheral surface 66, an inner peripheral surface 68, and a base surface 70. The sealing arrangement differs from the arrangement shown in FIG. 3C in that the sealing element 52 simultaneously contacts all of the surfaces 66, 68, 70 of the sealing element recess 64 to which it is mounted. The locations of the outer peripheral surface 66, an inner peripheral surface 68, and a base surface 70 are configured to allow simultaneous contact with the sealing element 52 when mounted to the sealing element recess 64.

(40) While it is believed possible to use a sealing element (not shown) having a cross-sectional dimension exactly equal to a recess channel distance S.sub.RD, which is measurable between the outer peripheral surface 66 and an inner peripheral surface 68, the example sealing element 52 shown has a normally circular cross-section with a diameter S.sub.D (not shown) slightly larger than the cross-sectional dimension recess channel distance S.sub.RD. Due to the slight compression the sealing element 52 undergoes during mounting to the sealing element recess 64, linear sections 53 are shaped in the cross-section of FIG. 4, where contact with the outer peripheral surface 66 and inner peripheral surface 68 is made. Accordingly, in a direction D.sub.P perpendicular to the base surface 70, the sealing element 52 has a dimension having a greater magnitude than the diameter S.sub.D thereof when uncompressed. Similarly, in theory, upon engagement of the sealing element 52 with a parting blade (not shown), similar linear sections will occur where contact with the parting blade and contact with the base surface 70 occur.

(41) Thus, the sealing arrangement in FIG. 4 is constructed such that a projecting portion 55 of the seal 52 always projects a distance Sp in the direction D.sub.P from the holder connection surface 54. Even when the sealing element 52 is compressed by contact with a parting blade (not shown), such construction is believed to possibly be advantageous due to the simplicity and cost effectiveness thereof, even though such construction leaves a part of a sealing element in the expected flow path P.sub.F of pressurized fluid, which can be expected to damage such sealing element. Indeed, upon testing a sealing element (not shown) having a diameter of 2.5 mm in a recess having a recess depth S.sub.R, measured in the direction D.sub.P, of 2.05 mm (i.e. the depth being 82% of the diameter of the uncompressed sealing element), the sealing element indeed was damaged, the projecting portion thereof being completely removed. Even more surprising was the discovery that by increasing the size of the projecting projection 55 slightly, such damage did not occur. In a successful test, a sealing element shown having a diameter of 2.5 mm in a recess having a recess depth S.sub.R of 1.95 mm (i.e. the depth being 78% of the diameter of the uncompressed sealing element), the sealing element was not found to show signs of wear. Accordingly, it is believed that a recess depth to sealing element diameter ratio of about 1.95:2.5, i.e. about 78%, can possibly provide a suitable construction.

(42) In such testing it was also found that there was a remarkable seal formed, this being despite the fact that such construction does not provide a void in a sealing element recess for the sealing element to expand into. Such void allows pressurized fluid therein to compress the sealing element in a direction perpendicular to the direction D.sub.P and expand the sealing element further in the direction D.sub.P (which would be expected, in this application, to improve a sealing force between a parting blade and blade holder).

(43) Notwithstanding that such construction can tilt a parting blade from a desired parallel orientation relative to the holder connection surface 54, machining results are believed to remain satisfactory.

(44) Reverting to the remainder of the description, notably, the blade inlet aperture 26 can be sized to correspond to an internal height dimension H1 of the holder outlet aperture 20. More precisely, the blade inlet aperture's 26 internal height dimension H2, which in this example is also a diameter, can correspond in magnitude to the internal height H1 of the holder outlet aperture 20, for allowing efficient coolant transfer therebetween.

(45) Referring to FIG. 1C, each of the first and second longitudinal jaws 62A, 62B can comprise a slanted biasing surface 76A, 76B for biasing the parting blade 14, peripherally, against the holder connection surface 54. Each of the first and second longitudinal jaws 62A, 62B can comprise a relief recess 78A, 78B located inward of the biasing surface 76A, 76B.

(46) The first longitudinal jaw 62A can have a unitary construction with the remainder of the blade holder 12, except, in this example, with the second longitudinal jaw 62B.

(47) The second longitudinal jaw 62B can be attached to the remainder of the blade holder 12 via at least one mounting bore 80 formed therein and in the blade holder 12 and secured with a screw 82. Each mounting bore 80 can be directed towards the deceleration chamber 22, as opposed to being oriented in the direction of arrow 58, the latter of which might, in some circumstances, cause an unwanted protrusion of a screw portion past the parting blade 14. Each mounting bore 80 can be a blind bore, restricted in length so as not to open out to or weaken an associated deceleration chamber 22. Additionally, each mounting bore 80 can be located spaced-apart from the sealing element recess 64 (best shown in FIG. 3B). The second longitudinal jaw 62B can also comprise a jaw securing surface 84, configured for being biased against a corresponding holder securing surface 86, for biasing the parting blade 14 against the holder connection surface 54.

(48) Referring now to FIGS. 3A to 3C, it is shown that the holder passageway 16 can comprises a transition region 88 at which the preceding portion 21 transforms into the deceleration chamber 22. Including the transition region 88, the deceleration chamber 22 has a length L.sub.D along second direction 48.

(49) One of the ways that the deceleration of coolant in the deceleration chamber 22 can occur can be a result of the deceleration chamber 22 having a greater cross-sectional area than a cross-sectional area of the preceding portion.

(50) More precisely, the deceleration chamber 22 can comprise a deceleration chamber cross-sectional area A.sub.D1, extending perpendicular to the first path portion 42A of the deceleration chamber 22 at the transition region 88, which is greater than a preceding portion cross-sectional area A.sub.P of the preceding portion 21 (which in this non-limiting example is a circle) at the transition region 88. In this example, the deceleration chamber cross-sectional area A.sub.D1 is rectangular having a length dimension L.sub.D and a width dimension W.sub.D, and accordingly fulfilling the condition L.sub.DW.sub.D=A.sub.D1. While the design shown illustrates a deceleration chamber cross-sectional area A.sub.D1 having a magnitude about 2.6 times as large as the preceding portion cross-sectional area A.sub.P, it will be understood that a larger ratio would also provide the desired effect. Similarly, in theory, a ratio of 2:1 or a ratio at least greater than 1.5:1 is possibly feasible.

(51) It will be understood that, referring to cross-sections perpendicular to a flow path, a cross-sectional area anywhere in the deceleration area which is greater than a cross-sectional area in the preceding portion could provide deceleration. However, a relatively greater cross-sectional area of the deceleration chamber 22 at the transition region 88 may be advantageous. In theory: a relatively greater cross-sectional area of the deceleration chamber 22 at the transition region 88 may complement deceleration at the barrier surface 90; deceleration at the start of the deceleration chamber 22 may decelerate the flow to a velocity which, even if there is an increase in velocity at a later section of the deceleration chamber 22, does not provide sufficient time for the flow to increase to the velocity of the preceding portion 21; stated differently, cross sectional areas in the deceleration chamber 22 subsequent to the preceding portion 21 may all be smaller than the cross-sectional area thereat; alternatively, even if the deceleration chamber 22 would have a cross-sectional area corresponding in size to the preceding portion 21, the deceleration chamber 22 may be sized such that flow does not increase to the velocity of the preceding portion 21 (e.g. sufficiently short in length in a direction of the flow path).

(52) It will also be understood that, without specifying cross sections, the deceleration chamber 22 can be shaped (e.g. by having a larger volume or cross section than the preceding portion 21) to decelerate fluid from the preceding portion 21. It is also noted that the width dimension W.sub.D has a greater magnitude than the length dimension L.sub.D, facilitating a possibly advantageous range of movement of the parting blade 14.

(53) It is also noted that, in this example, the holder outlet aperture 20 comprises an identical cross-sectional area to the deceleration chamber 22. More precisely, a cross-sectional area of the holder outlet aperture 20 can correspond to a cross-sectional area of the deceleration chamber 22 extending perpendicular to the coolant path 42, 42A adjacent (generally designated with arrow 23) the holder outlet aperture 20.

(54) Another way in which the deceleration of coolant in the deceleration chamber 22 can occur can be a result of the deceleration chamber 22 comprising a barrier surface 90 facing the first path portion 42A of the coolant path in the preceding portion 21 at the transition region 88. In theory, deflection of coolant in a direction against the first direction 44, and in this example, in an opposite direction to the first direction 44, can reduce the speed of coolant entering the deceleration chamber 22. It will be understood that increased proximity of the barrier surface 90 to the preceding portion 21 at the transition region 88 could result in a greater reduction of speed. In this example it is noted that the deceleration chamber 22 is configured with the smallest dimension thereof (H.sub.D) extending from the preceding portion 21 at the transition region 88 to the barrier surface 90. To bring perspective to the proximity in the present example, it is noted that such height H.sub.D, in this example is 2.5 mm. Such height H.sub.D could be increased, for example, for this particular design up to 3 mm, however at distances greater than 3 mm significant constructional modifications may be required. It will be understood that the height dimension H.sub.D of the deceleration chamber 22 at the transition region 88 may be the same as the internal height dimension H1 of the holder outlet aperture 20, though it is possible that they may differ slightly.

(55) It will be understood that a combination of both construction concepts above, each being configured in achieving deceleration of coolant in a different way, can, possibly, provide greater deceleration than one of the constructions alone.

(56) Referring now to FIGS. 1B and 2A to 2C, the parting blade 14 will be described in more detail.

(57) The parting blade 14 can be elongated with opposing planar first and second side surfaces 50A, 50B extending between parallel first and second longitudinal mounting edges 92A, 92B and between opposing first and second end edges 94A, 94B which extend transverse to the longitudinal mounting edges 92A, 92B. The parting blade 14 is narrow. A first spacing between the first and second side surfaces 50A, 50B defines the parting blade width W.sub.P, which, as seen in FIGS. 2A, 2B and 2C is considerably smaller than both a second spacing between the parallel first and second longitudinal mounting edges 92A, 92B and a third spacing between the opposing first and second end edges 94A, 94B.

(58) Each of the first and second longitudinal mounting edges 92A, 92B can have a tapered shape with slanted surfaces which can facilitate longitudinal sliding motion relative to the blade holder 12.

(59) The parting blade 14 can have 180 degrees rotational symmetry about a blade axis (A.sub.B) which extends through the center of, and in a direction perpendicular to, the first and second side surfaces 50A, 50B. Such construction can allow a single parting blade to comprise more than one cutting portion.

(60) The parting blade 14 can be symmetrical about a bisecting plane P.sub.P extending parallel with and equally spaced from the first and second side surfaces 50A, 50B. Such construction can allow a single parting blade to be compatible for different cutting machines or cutting applications.

(61) The parting blade 14 may have a lateral plane P3 which is perpendicular to the first and second side surfaces 50A, 50B, and is located midway between the end edges 94A, 94B. In some embodiments (not shown), the parting blade may have mirror symmetry about the lateral plane P3, and thus be double-ended but not rotationally symmetric about the aforementioned blade axis (A.sub.B).

(62) In view of the above-mentioned symmetry, the following description will relate to only one of the blade passageways 24 and the cutting portion 30 associated therewith. Such symmetry is only intended to relate to the body of the parting blade body itself and not associated non-integral components such as cutting inserts (wherein typically only one is mounted at any given time to allow greater range of motion of the parting blade) or sealing devices, which are only needed in one of the plurality of possible positions therefor at a given time. The cutting portion 30 described below is the one associated with the first longitudinal mounting edge 92A and the first end edge 94A.

(63) In this example, the blade inlet aperture 26 opens out to both the first and second side surfaces 50A, 50B.

(64) To prevent coolant (not shown) exiting the blade inlet aperture 26 at the second side surface 50B, the parting blade 14 is provided with a sealing aperture 96 (FIG. 2A), which in this example is threaded, to which the sealing device 56 (FIG. 1C) can be fastened.

(65) The sealing device 56 can be a screw 98 and annular seal 100, the latter of which can be made of a rigid material, for example metal. The screw 98 can extend through the annular seal 100 and can be fastened to the sealing aperture 96.

(66) The sealing aperture 96 is adjacent to the blade inlet aperture 26, and the annular seal 100 extends over and seals the blade inlet aperture 26 to prevent coolant exiting therefrom.

(67) The sealing device 56 can be configured to be detached from the parting blade 14 (in this example they are connected via threading), allowing it to be mounted to the other end of the same sealing aperture 96 or to another sealing aperture of the parting blade 14, when needed.

(68) It has been found that it can be advantageous to restrict the movement of the parting blade 14 in the blade holder 12, in accordance with the location of the sealing element and the parting blade. In particular, it has been found that unrestricted motion of the parting blade 14, allowing one of the sealing apertures 96 to be disposed near or facing the sealing element 52, can result in undesired deflection of pressurized coolant. In theory, such deflection is believed to be caused by contact of the coolant with the sealing aperture 96 and/or the sealing device 56, onto the sealing element 52 causing damage thereto.

(69) The blade passageway 24 has a uniform cross-sectional area perpendicular to the second path portion 42B which extends therethrough. One possibly advantageous construction of the blade passageway 24 can be production of a straight first sub-passageway 102A, starting at a first sub-passageway aperture 104 and extending to the blade inlet aperture 26, and production of a straight second sub-passageway 102B, starting at the blade outlet aperture 28 and extending to the first sub-passageway 102A. The second sub-passageway 102B can intersect the first sub-passageway 102A at an obtuse angle. The first sub-passageway aperture 104 is subsequently sealed to ensure coolant is directed from the blade inlet aperture 26 to the blade outlet aperture 28.

(70) The straight second sub-passageway 102B can be directed at a cutting edge 36 associated with the cutting portion 30 and/or workpiece (not shown).

(71) It has been found that application of pressurized coolant, in particular for pressures above 20 bar, is more effective when a only single passageway 24 to an associated cutting portion 30 is utilized. It has also been found that directing coolant to the cutting edge 36, adjacent a rake face 38, as shown in FIG. 1B, is more effective than directing coolant to the cutting edge 36, adjacent a relief surface 40 thereof. Accordingly, in the non-limiting example shown, the blade outlet aperture 28 is located at a portion of the cutting portion 30 that is closer to the first longitudinal mounting edge 92A than to the first end edge 94A.

(72) While the example above relates to a blade passageway 24 with a uniform cross-sectional area, it will also be understood that it is possible to decrease the cross sectional area of the blade passageway 24 with increased proximity to the cutting portion 30, with a different possible advantage of increasing the speed of coolant passing therethrough. However, it has been found that limiting a ratio of the magnitudes of a maximum cross-sectional area, closer to the blade inlet aperture, and a minimum cross-sectional area, closer to the blade outlet aperture, to 2:1 or less can ensure maintenance the simple construction of the exemplified parting blade.

(73) The description above includes an exemplary embodiment and details, and does not exclude non-exemplified embodiments and details from the claim scope of the present application.