Self-aligning type knurling device

Abstract

To provide a knurling device which enables vertical inversion of knurling pieces and enables centering of the knurling pieces to be performed safely before and after the inversion.SOLUTION: A self-aligning type knurling device A includes: a shank 10; an attachment block 20 attached to the shank 10 in a manner that enables vertical inversion; slide shafts 35, 36 provided in parallel to the attachment block 20; a movement block 40 attached to the slide shafts 35, 36 movably in a vertical direction; and knurling pieces 56, 57 held in a vertical direction by a tip of the movement block 40. Resilient materials 47, 48 are attached to at least one of the slide shafts 35, 36. The knurling pieces 56, 57 are held by the movement block 40 so that a parallel line CL2 which is parallel to a center line CL1 and passes through an intermediate point O between the knurling pieces 56, 57 deviates from the center line CL1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] To provide an automatic centering type knurling device capable of knurling the vicinity of a chuck or the corners of a stepped portion of a workpiece by reversing knurling pieces attached asymmetrically to the left and right, which can safely perform the automatic centering action, can fix the knurling pieces as needed, and is also excellent in durability and capable of automatic centering. [Background technology]

[0002] The knurling device has a knurling piece rotatably attached to the tip of a shank, and the knurling piece is pressed against the surface of a rotating workpiece to knurl the surface. To accurately and beautifully finish the knurled grooves, it is extremely important to align the center of the workpiece with the center of the knurling tool of the knurling device.To align the center, the worker moves the tool post of the lathe up and down to perform rough centering, and finally inserts a shim between the shank and tool post of the knurling device to perform the final center adjustment.This adjustment took a great deal of time.

[0003] Furthermore, the workpieces are not simply cylindrical but also have steps. The area requiring knurling may be near the chuck of the lathe or even the very corners of the steps in the workpiece. A knurling device that can quickly perform such center adjustment and can also perform knurling near the chuck of a lathe or to the very corners of steps in a workpiece is disclosed in Patent Document 1.

[0004] The knurling device disclosed in Patent Document 1 is an automatic centering type device in which a mounting block is attached to the tip of the shank with a single bolt pin so that it can swing up and down, and two knurled pieces are cantilevered on the side of the tip of the mounting block, one above the other. This knurling device can be attached to the shank by inverting the mounting block with the knurling piece attached. This makes it possible to perform knurling near the chuck of the lathe or to the very corners of steps. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Utility Model Registration No. 3137810 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in this knurling device, the mounting block equipped with the knurling piece is pivotally attached to the shank by a single bolt pin so that it can swing freely. Therefore, the knurling piece is moved in the direction of the rotating workpiece, and the mounting block must be supported with the fingers until the upper and lower knurling pieces are pressed against the workpiece and centering is complete. This makes the knurling work dangerous as there is a risk that the hand will get caught in the rotating workpiece.

[0007] There is also a knurling device that can hold a holding member equivalent to a mounting block in its initial position without requiring finger support during centering (Japanese Patent Application Laid-Open No. 11-10413), but this knurling device is not designed to allow the holding member to be inverted upside down, and therefore the mechanism that holds it in its initial position is not designed to accommodate inversion.

[0008] The present invention has been made in view of the problems of the conventional example, and a main object of the present invention is to enable safe centering before and after reversal in a knurling device in which the knurling piece can be turned upside down. [Means for solving the problem]

[0009] The self-centering knurling device A described in claim 1 is A shank 10 attached to the tool post M, a mounting block 20 that is mounted on the shank 10 so as to be upside down about a center line CL1 extending in the longitudinal direction of the shank 10 as a rotation center; slide shafts 35 and 36 arranged side by side on the mounting block 20 in the vertical direction; a moving block 40 attached to the slide shafts 35 and 36 so as to be movable in the up and down direction; The moving block 40 is provided with knurled pieces 56 and 57, which are held above and below the tip of the moving block 40. At least one of the slide shafts 35 and 36 is provided with elastic members 47 and 48 for elastically biasing the moving block 40 from above and below. The knurling pieces 56 and 57 are held by the moving block 40 so that a parallel line CL2 that is parallel to the center line CL1 and passes through a midpoint O between the knurling pieces 56 and 57 deviates from the center line CL1 in the width direction of the knurling pieces 56 and 57.

[0010] Claim 2 relates to the arrangement of the slide shafts 35 and 36 and the resilient members 47 and 48 (FIG. 10). Claim 2 relates to the self-centering type knurling device A according to claim 1, One of the slide shafts 35 is installed at a position behind the knurled pieces 56 and 57 where the parallel line CL2 passes. The other slide shaft 36 is disposed at a position away from the back of the knurled pieces 56, 57, and the resilient members 47, 48 are disposed on the other slide shaft 36.

[0011] Claim 3 relates to fixing the moving block 40 to the mounting block 20 (FIG. 10). Claim 3 relates to the self-aligning knurling device A according to claim 1 or 2, A plate portion 41 is provided on the rear surface of the moving block 40 so as to protrude rearward, and a long hole 49 is drilled in the plate portion 41 in parallel with the slide shafts 35 and 36. The mounting block 20 is characterized in that it is provided with fixing screws 60 that are inserted into the elongated holes 49 and fix the plate portion 41 to the mounting block 20.

[0012] Claim 4 relates to the attachment of the mounting block 20 to the shank 10 (FIG. 1). Claim 4 relates to the self-aligning knurling device A according to claim 1 or 2, The shank 10 is composed of a shank body 10a and shank-side arms 11 and 12 provided on the front surface of the shank body 10a. The mounting block 20 is provided with mounting side pieces 21 and 22 that are attached to the shank side arms 11 and 12, The mounting surfaces 11a, 11b and 12a, 12b to which the mounting pieces 21, 22 of the shank-side arms 11, 12 are attached are provided symmetrically with respect to the center line CL1 of the shank 10, The attachment portions 25 and 26 of the attachment side pieces 21 and 22 to the shank side arms 11 and 12 are characterized in that they pass through the midpoint O between the knurled pieces 56 and 57 and are arranged symmetrically in a front view with respect to a parallel line CL2 extending parallel to the center line CL1.

[0013] Claim 5 relates to the case where the knurling pieces 56 and 57 are supported at both ends (first embodiment), and in the self-aligning knurling device A according to claim 1 or 2, A piece-holding notch 44 is recessed in the top and bottom direction at the tip of the moving block 40 in line with the parallel line CL2, and piece-holding wall surfaces 42 and 43 for holding the knurled pieces 56 and 57 are formed on both sides of the piece-holding notch 44, One of the piece-holding wall portions 42 is thinner in width than the other piece-holding wall portion 43.

[0014] Claim 6 relates to a case where the knurling pieces 56 and 57 are supported by a cantilever (second embodiment), and in the self-aligning knurling device A according to claim 1 or 2, A piece-holding notch 44 is recessed into one of the side surfaces 40a (40b) of the tip of the moving block 40 in line with the parallel line CL2, and a piece-holding wall surface 43a that cantilevers the knurled pieces 56 and 57 is formed in the piece-holding notch 44. [Effects of the Invention]

[0015] According to the present invention, the mounting block 20 can be attached to the shank 10 so that it can be turned upside down. Therefore, by turning the mounting block 20 over, the knurling pieces 56, 57 held asymmetrically in the mounting block 20 can be easily switched from left to right, and knurling can be performed up to the corner S of the stepped portion of the workpiece W and near the chuck 80.

[0016] At least one of the slide shafts 35, 36 arranged in parallel in the vertical direction on the mounting block 20 is provided with elastic members 47, 48 that apply elastic forces to the moving block 40 from above and below, so that the worker does not need to support the knurled pieces 56, 57 or the moving block 40 with his fingers during the alignment work, thereby enabling safe automatic alignment. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a front view of a knurling device (first embodiment) according to the present invention. [Figure 2] FIG. 2 is a plan view of FIG. [Figure 3] FIG. 10 is a plan view showing the mounting block with the moving block attached thereto inverted relative to the shank. [Figure 4] FIG. 2 is an exploded front view of the moving block, the mounting block, and the shank of FIG. 1. [Figure 5] FIG. 5 is a longitudinal sectional view of FIG. [Figure 6] FIG. 5 is a plan view of FIG. [Figure 7] XX cross-sectional view of FIG. 2. [Figure 8] FIG. 3 is a cross-sectional view of FIG. 2 taken along the line Y-Y. [Figure 9]FIG. 6 is a vertical half-sectional perspective view of the moving block, the mounting block, and the shank shown in FIG. 5. [Figure 10] 1 is an exploded perspective view of a knurling device (first embodiment) according to the present invention. [Figure 11] FIG. 10 is a partially exploded perspective view of a second embodiment according to the present invention in which the knurling piece is cantilevered. [Figure 12] FIG. 12 is a cross-sectional view of the knurled piece portion of FIG. 11. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described with reference to the illustrated embodiments. The self-centering knurling device A of the present invention comprises a shank 10, a mounting block 20, a movable block 40, slide shafts 35 and 36, resilient members 47 and 48, knurling pieces 56 and 57, a fixing screw 60, and accessory parts. The self-centering knurling device A of the present invention is available in a first embodiment (knurling pieces supported on both sides) shown in FIGS. 1 to 10 and a second embodiment (knurling pieces supported on one side) shown in FIGS. 11 and 12. First, the first embodiment will be described, and then the second embodiment will be described mainly focusing on the differences from the first embodiment. For the same parts as the first embodiment, the description of the first embodiment will be applied to the second embodiment.

[0019] (First embodiment) The shank 10 is a component attached to the tool post M of the lathe and is composed of a prismatic shank body 10a with its underside machined into an inverted L shape, and shank-side arms 11 and 12 that protrude forward from the upper and lower ends of the tip face of the shank body 10a. The space between the shank-side arms 11 and 12 is an insertion groove 13 into which a plate portion 41 of a moving block 40, described below, fits. The underside of the shank body 10a, which is cut into an inverted L shape, is the mounting surface 10m that is attached to the tool post M, and serves as the reference surface for the self-aligning knurling device A of the present invention.When attached to the tool post M, its extension line coincides with the center of rotation of the workpiece W. The line that coincides with this mounting surface 10m, passes through the center of the shank body 10a in a plan view, and extends in the longitudinal direction of the shank 10 is the center line CL1 of the shank 10, which serves as the reference for reversing the knurling pieces 56 and 57 (Figures 1 and 2).

[0020] As shown in FIG. 2, a parallel line CL2 that is parallel to the center line CL1 of the shank 10 and passes through a midpoint O between the knurling pieces 56 and 57 in the thickness direction is set so as to deviate from this center line CL1 by a deviation width La in the width direction of the knurling pieces 56 and 57, and the knurling pieces 56 and 57 are held by the moving block 40 so as to be deviated from the center line CL1 by the deviation width La. During knurling, as shown in Figure 1, the knurling pieces 56 and 57 are held so that the extension of the mounting surface 10m including the center line CL1 passes through the midpoint O between the upper and lower knurling pieces 56 and 57 in a front view. In other words, during knurling, the midpoint O between the upper and lower knurling pieces 56 and 57 is automatically aligned so that it coincides with the center line CL1 in a front view.

[0021] Shank-side arms 11 and 12 are provided above and below center line CL1 of shank 10, straddling it, and have through holes 15 and 16 drilled in their sides, respectively. These through holes 15 and 16 are mounting portions for mounting block 20, which will be described later, and are provided symmetrically with respect to center line CL1 of shank 10, so that mounting block 20 can be mounted to shank 10 upside down around center line CL1.

[0022] The width of the shank side arms 11 and 12 is smaller than the width of the shank body 10a, and as shown in Figure 6, in a plan view, the distance L3 from the center line CL1 to the mounting surfaces 11a and 11b / 12a and 12b of the mounting block 20, which are the sides of the shank side arms 11 and 12, is equal, and the center line CL1 passes through the center of the shank side arms 11 and 12.

[0023] The mounting block 20 is attached to the shank-side arms 11 and 12 of the shank 10 so as to be upside down about the center line CL1 of the shank 10. A mounting groove 23 is formed in the shank-side back surface of the mounting block 20, extending from the top to the bottom, with mounting pieces 21 and 22 provided on either side of the mounting groove 23. The opening width of the mounting groove 23 is approximately equal to the width of the shank-side arms 11 and 12 of the shank body 10a, and is formed to be insertable and detachable.

[0024] The mounting side pieces 21 and 22 of the mounting block 20 are provided with mounting portions 25 and 26 for the shank side arms 11 and 12. In the illustrated embodiment, the bolt holes 25h and 26h and the screw holes 25n and 26n correspond to the mounting portions 25 and 26. That is, bolt holes 25h and 26h are drilled at the top and bottom of one mounting side piece 21 of the mounting block 20 at positions that correspond to the through holes 15 and 16 of the shank side arms 11 and 12, and screw holes 25n and 26n are drilled at the top and bottom of the other mounting side piece 22 at positions that similarly correspond to the through holes 15 and 16 of the shank side arms 11 and 12.

[0025] Between the bolt holes 25h and 26h and the screw holes 25n and 26n, there are provided large diameter holes 27 and screw holes 29, into which fixing screws 60 are inserted. In the illustrated embodiment, the large diameter holes 27 are provided at the midpoints of the bolt holes 25h and 26h, and the screw holes 29 are provided at the midpoints of the screw holes 25n and 26n.

[0026] 1, the large diameter hole 27 (fixing screw hole 29) is formed so that the center line CL1 of the shank 10 passes through the center point of the large diameter hole 27 (fixing screw hole 29) when viewed from the front. As will be described later, the moving block 40 can move up and down for alignment with the mounting block 20, and for this purpose, an elongated hole 49 is formed in the plate portion 41 of the moving block 40. Therefore, it is possible to form the large diameter hole 27 and the fixing screw hole 29 at positions deviated from the center line CL1 of the shank 10.

[0027] Large diameter hole 27 is drilled in one of the mounting pieces 21, and an O-ring receiving groove 27a is provided around its entire inner periphery. An O-ring 28 is fitted into O-ring receiving groove 27a. The inner periphery of O-ring 28 is exposed from O-ring receiving groove 27a to the inside of large diameter hole 27. Head 61 of fixing screw 60 is received in large diameter hole 27, and the inner diameter of O-ring 28 is smaller than the outer diameter of head 61 of fixing screw 60, so that the exposed portion engages with head 61 and prevents fixing screw 60 from coming loose. As described above, the other mounting piece 22 is provided with a fixing screw hole 29 into which the threaded portion of the fixing screw 60 is screwed.

[0028] A horizontal holding groove 33 is formed in the center of the front of mounting block 20, extending from one side surface to the other, and holding arms 31 and 32 protrude forward above and below the groove, straddling parallel line CL2 of mounting block 20. As will be described later, moving block 40 is held vertically by resilient members 47 and 48 and is inverted together with mounting block 20, so in the embodiment of Figure 1, holding arms 31 and 32 protrude symmetrically above and below parallel line CL2. As shown in Figure 1, it is preferable to hold the movable block 40 so that the distance Lb between the parallel line CL2 and the opposing surfaces of the holding arms 31 and 32 is equal while it is spring-balanced by the resilient members 47 and 48. However, since the movable block 40 is automatically centered by the resilient members 47 and 48, the holding arms 31 and 32 may be asymmetrical above and below about the parallel line CL2, unlike the embodiment shown in Figure 1.

[0029] The upper and lower holding arms 31 and 32 each have two holding holes 31h and 32h through which two slide shafts 35 and 36 are inserted in parallel. These slide shafts 35 and 36 are fixed to at least one of the holding arms 31 and 32. These slide shafts 35 and 36 are exposed within the holding grooves 33 between the holding arms 31 and 32. The parallel line CL2 of the mounting block 20 passes through one of the holding holes 31h and 32h in a plan view (Figure 2).

[0030] Furthermore, an insertion hole 38 is drilled in the center of the front surface of the mounting block 20, extending from the bottom of the front-side retaining groove 33 to the bottom of the rear-side mounting groove 23. This is indicated by a dashed line in FIG. 9. In FIG. 5, the bottom of the retaining groove 33 and the bottom of the mounting groove 23 are aligned, so the rectangular window enclosed by these grooves forms the insertion hole 38. Although not shown, if the bottoms of the retaining groove 33 and the mounting groove 23 are not aligned but separated, an insertion hole 38 extending from the retaining groove 33 to the mounting groove 23 would be drilled. The vertical dimension of this insertion hole 38 is larger than the vertical dimension of the plate portion 41, and as described below, the plate portion 41 of the moving block 40 is inserted into this insertion hole 38 so as to be movable up and down. In other words, the vertical inner dimension of the insertion hole 38 is large enough to allow the plate portion 41 to be inserted upside down and to move up and down with self-centering. The width of the insertion hole 38 is made approximately the same as the width of the plate portion 41 so that the plate portion 41 can be inserted and removed.

[0031] In the illustrated embodiment, since the plate portion 41 of the moving block 40 is inserted upside down into this insertion hole 38 as described above, this insertion hole 38 is drilled so that the parallel line CL2 of the mounting block 20 passes through the center of this insertion hole 38. In other words, the insertion hole 38 is drilled so that the parallel line CL2 of the mounting block 20 passes through the center of the insertion hole 38 in the up-down and lateral directions.

[0032] The moving block 40 is placed in front of the mounting block 20, and the plate portion 41 is inserted into the insertion hole 38 of the mounting block 20, with its tip held between the mounting side pieces 21 and 22. In this state, the elongated hole 49 of the plate portion 41 is aligned with the large diameter hole 27 (fixing screw hole 29).

[0033] The fixing screw 60 to be fitted into the large diameter hole 27 is a pan head screw with a hemispherical head 61. The diameter of the head 61 of the fixing screw 60 is smaller than the inner diameter of the large diameter hole 27 provided in one of the mounting pieces 21, so that when the fixing screw 60 is tightened, the head 61 comes into direct contact with the plate portion 41 of the moving block 40 via a washer 63, which is provided as needed. The leg portion 62 of the fixing screw 60 passes through the elongated hole 49 of the plate portion 41 and is threaded into the fixing screw hole 29 provided in the other mounting piece 22.

[0034] Bolts 70 and 71 are inserted through the bolt holes 25h and 26h in one mounting side piece 21 of the mounting block 20 and the through holes 15 and 16 in the shank 10, and are screwed into the screw holes 25n and 26n in the other mounting side piece 22 of the mounting block 20 to form an integrated unit.

[0035] The moving block 40 is attached to the front surface of the mounting block 20 on the slide shafts 35 and 36 of the mounting block 20 so as to be movable up and down. TIFF2025122418000002.tif52 A base 40k smaller than the inner dimensions between the top and bottom of the retaining groove 33 between the retaining arms 31 and 32 of the mounting block 20 is provided on the back side of the movable block 40, and further a plate portion 41 which can be inserted into the insertion hole 38 protrudes rearward from the back of the base 40k.

[0036] The base portion 40k is provided with slide holes 45 and 46 that coincide with the holding holes 31h and 32h, and the slide shafts 35 and 36 are inserted therethrough so as to be slidable in the vertical direction. The rear end of the plate portion 41 is provided with an elongated hole 49 that is parallel to the slide shafts 35 and 36 in the vertical direction. During assembly, the elongated hole 49 is provided at a position that coincides with the large diameter hole 27 (fixing screw hole 29) as described above.

[0037] The fixing screws 60 are loosely attached to the mounting block 20 in a state that allows the moving block 40 to move up and down as described above. If necessary, the fixing screws 60 can be tightened in cooperation with the bolts 70 and 71 to integrate the moving block 40 with the mounting block 20.

[0038] A groove-shaped piece-holding notch 44 is dug vertically through the tip of the moving block 40, and piece-holding wall surfaces 42 and 43 are provided on both sides of the notch. A parallel line CL2 passing through the midpoint of the link retaining notch 44 in the width direction (in other words, the midpoint O between the knurled pieces 56 and 57) is spaced a distance La from the center line CL1 of the shank in a plan view (FIG. 2). In other words, the link retaining notch 44 is formed so that the parallel line CL2, which is parallel to the center line CL1 and passes through the midpoint O between the knurled pieces 56 and 57 in the thickness direction, is offset from the center line CL1 in the width direction of the knurled pieces 56 and 57.

[0039] On either side of bridge-retaining cutout 44 are bridge-retaining walls 42 and 43, one of which is thinner than the other, and bridge-retaining walls 42 and 43. Bridge-retaining shafts 52 and 53 are inserted parallel to and through the top and bottom of bridge-retaining walls 42 and 43 from side surfaces 40a and 40b and secured in place with set screws. The vertical line connecting the centers of bridge-retaining shafts 52 and 53 coincides with a line perpendicular to parallel line CL2 that passes through the midpoint between bridge-retaining shafts 52 and 53 (in other words, the midpoint O of the knurled bridge) (Figure 1).

[0040] Knurled pieces 56 and 57 are rotatably inserted into the piece holding shafts 52 and 53, respectively, and these knurled pieces 56 and 57 are held close to one of the piece holding wall portions 42. In other words, the knurled pieces 56 and 57 are held so that the distances from the side surfaces 40a and 40b of the moving block 40 to the centers O of the knurled pieces 56 and 57 in the thickness direction are asymmetrical (FIG. 2).

[0041] The knurling pieces 56 and 57 are ring-shaped members of the same diameter made of high-speed steel or carbide material, with fine knurling grooves formed on their outer peripheries for forming the knurls. The thickness of the knurling pieces 56 and 57 is approximately the same as the opening width of the piece-retaining cutout 44, so the knurling pieces 56 and 57 do not wobble left and right within the piece-retaining cutout 44 during rotation.

[0042] Regarding the positional relationship between the slide shafts 35 and 36 attached to the mounting block 20 and the knurled pieces 56 and 57, one of the slide shafts 35 is located behind the midpoint O in the thickness direction of the knurled pieces 56 and 57, and the other shaft 36 is located at a position offset to the side from the rear of the midpoint O (Figure 2).

[0043] In the illustrated embodiment, the parallel line CL2 passing through the midpoint O is set to pass through the center of one of the slide shafts 35. Of course, the positional relationship between the two is not limited to this, and it is sufficient that one of the slide shafts 35 is located within a range where it can bear the reaction force F from the knurled pieces 56 and 57, that is, behind the knurled pieces 56 and 57. In other words, it is sufficient that the center of one of the slide shafts 35 is located within the range of the lateral width of the knurled pieces 56 and 57.

[0044] The slide hole 46 through which the other shaft 36 is inserted is located to the side of one slide hole 45, and above and below it are formed spring housing holes 46a and 46b whose diameter is larger than the inner diameter of the slide hole 46. These spring housing holes 46a and 46b house resilient members 47 and 48, which sandwich the base 40k of the moving block 40 from above and below, applying a resilient force to it. This allows the moving block 40 to be self-centered.

[0045] 7, the spring housing holes 46a and 46b are formed to the same depth and house elastic members 47 and 48 with the same elastic force (spring coefficient). As a result, the parallel line CL2 passing through the midpoint O between the knurled pieces 56 and 57 of the moving block 40 attached to the mounting block 20 substantially coincides with the center line CL1 of the shank before and after reversal. Note that although the spring housing holes 46a and 46b are formed on the base 40k side of the moving block 40, they may also be formed on the holding arms 31 and 32 sides.

[0046] In this embodiment, helical springs are used for the resilient members 47 and 48. Disc springs or rubber can also be used instead of helical springs. The resilient members 47 and 48 are housed in the spring housing holes 46a and 46b of the movable block 40 as described above, and abut against the opposing surfaces of the front-side retaining arms 31 and 32 on the mounting block 20 side, sandwiching the base 40k of the movable block 40 from above and below, applying elastic force to it. The movable block 40 is held to the mounting block 20 by the spring balance of the upper and lower resilient members 47 and 48. With the above-described configuration, before and after reversal, under spring balance, the parallel line CL2 passing through the midpoint O of the knurled pieces 56 and 57 approximately coincides with the center line CL1 of the shank when viewed from the front in FIG. 1.

[0047] The mounting of the mounting block 20 to the shank 10 will now be described. The mounting block 20 is attached to the shank-side arms 11 and 12 of the shank body 10a with bolts 70 and 71. That is, the bolts 70 and 71 are inserted through bolt holes 25h and 26h provided in one mounting side piece 21 of the mounting block 20 and through holes 15 and 16 in the shank-side arms 11 and 12 inserted between the left and right mounting side pieces 21 and 22, and are screwed into threaded holes 25n and 26n provided in the other mounting side piece 22 of the mounting block 20.

[0048] The fixing screw 60 is inserted into the large diameter hole 27 provided in one of the mounting side pieces 21 of the mounting block 20, and its leg 62 passes through the elongated hole 49 drilled in the plate portion 41 of the moving block 40 inserted into the mounting groove 23 between the shank side arms 11 and 12 of the shank 10 and the mounting side pieces 21 and 22 of the mounting block 20, and is screwed into the fixing screw hole 29 provided in the other mounting side piece 22 of the mounting block 20.

[0049] When the upper and lower bolts 70 and 71 are tightened, the mounting block 20 is fixed integrally to the shank 10, but when the fixing screw 60 is loosened, the plate portion 41 of the moving block 40 is not fixed to the mounting block 20, and the moving block 40 moves up and down along the slide shafts 35 and 36 under spring balance. In this state, the elastic force (spring coefficient) of the elastic members 47 and 48 is set so that the parallel line CL2 on the moving block 40 side is positioned almost close to the center line CL1, which serves as the reference on the shank 10 side.

[0050] The workpiece W may be a simple uniform round bar material, a round bar material with steps, etc. The parts that require knurling vary, such as part or the entire round bar material, the part near the chuck, or the corners of the steps.

[0051] Next, the operation of installing the self-centering knurling device A thus assembled on the tool rest M of the lathe and performing knurling will be described. When the mounting surface 10m of the shank 10 of the knurling device A of the present invention is placed on the tool post M, the parallel line CL2 on the moving block 40 side is positioned almost close to the center line CL1 of the shank 10 under spring balance. Next, in this state, the workpiece W is fixed between the chuck 80 of the lathe and the center 81 of the tailstock, and the workpiece W is rotated. The tool post M is brought close to the rotating workpiece W, and the knurling pieces 56 and 57 of the knurling device A are pressed against it.

[0052] If the parallel line CL2 passing through the midpoint O of the knurling pieces 56, 57 is slightly misaligned with the center of rotation of the workpiece W and one of the knurling pieces 56, 57 comes into partial contact with the workpiece W, the moving block 40 moves upward or downward against the resilient members 47, 48 as the knurling device A advances, and due to an automatic centering action, the parallel line CL2 passing through the center of rotation of the workpiece W and the midpoint O of the knurling pieces 56, 57 coincides with the center line CL1 of the shank 10, which is the reference line.

[0053] Here, the knurling device A can be used in two ways: with the fixing screws 60 loosened to perform knurling, or with the fixing screws 60 tightened to keep the moving block 40 fixed.

[0054] (When knurling with the fixing screw 60 loosened) In this state, the knurling device A is advanced and knurling is performed at the required locations. If it is required to perform knurling near one chuck 80 or up to the corner S of the stepped portion of the workpiece W, since the knurling pieces 56, 57 are held asymmetrically by the moving block 40 in this invention, the thinner piece-holding wall portion 42 is positioned on the chuck 80 side or the corner S side of the stepped portion, and knurling is performed thereon. If the knurling width is wider than the width of the knurling pieces 56 and 57, the knurling device A is moved parallel to the workpiece W. During this movement, the head 61 of the loosened fixing screw 60 engages with the O-ring 28 and will not fall out of the large-diameter hole 27.

[0055] Fine chips are generated during knurling, and if these chips get in between the knurling pieces 56, 57 and the workpiece W, they will cause misalignment and prevent a clean knurl. If there is a risk of this happening, tighten the fixing screws 60 once the centering of the knurling pieces 56, 57 is complete, and fix the moving block 40 to the mounting block 20 as a unit. This will eliminate the adverse effects of chips. When knurling a large number of workpieces W of the same diameter, since the moving block 40 is fixed to the mounting block 20, misalignment will be eliminated, and productivity can be increased.

[0056] If it is necessary to perform the knurling up to the corner S of the step on the opposite side, or if the wide piece-holding flat portion 43 is located on the chuck 80 side, it is necessary to turn the knurling pieces 56 and 57 upside down while the shank 10 remains attached to the tool post M. To do this, while the shank 10 remains attached to the tool post M, the fixing screw 60 and the upper and lower bolts 70 and 71 are removed, and the mounting block 20 is removed along with the movable block 40. Next, the mounting block 20 with the movable block 40 attached is turned upside down, and the mounting pieces 21 and 22 of the mounting block 20 are fixed to the shank-side arms 11 and 12 of the shank 10 with the bolts 70 and 71. Since the movable block 40 is turned over while still attached to the mounting block 20, the plate portion 41 of the movable block 40 is turned over while sandwiched between the mounting pieces 21 and 22 of the mounting block 20. In this turned over state, the elongated hole 49 is aligned with the large-diameter hole 27 and the fixing screw hole 29 of the mounting pieces 21 and 22. After that, the fixing screw 60 is inserted into the large-diameter hole 27, and the leg portion 62 is screwed into the fixing screw hole 29. The fixing screw 60 is left in its loosened state.

[0057] The through holes 15 and 16 of the shank-side arms 11 and 12 of the shank 10 are arranged symmetrically about the center line CL1 of the shank 10, and the mounting portions 25 and 26 (bolt holes 25h and 26h, screw holes 25n and 26n) and knurling pieces 56 and 57 provided on the mounting side pieces 21 and 22 of the mounting block 20 are arranged symmetrically in the up-down direction about a parallel line CL2 that substantially coincides with the center line CL1. Therefore, when the mounting block 20 is inverted, the knurling pieces 56 and 57 are inverted substantially about the center line CL1. As a result, the knurling pieces 56 and 57 are upside down with respect to the shank 10 attached to the tool post M, and the positions of the piece-holding wall portions 42 and 43 are inverted. By turning it over in this way and carrying out the knurling as described above, it is possible to carry out the knurling up to the vicinity of the chuck 80 or the corner S of the stepped portion on the opposite side. By tightening the fixing screw 60, the misalignment is corrected as described above.

[0058] In the above knurling process, a vertical reaction force F is applied to the knurling pieces 56 and 57 from the workpiece W in plan view (Fig. 2). This vertical reaction force F is applied to both slide shafts 35 and 36 via the moving block 40, but most of it is applied to one of the slide shafts 35, which is provided behind the knurling pieces 56 and 57. A small moment force centered on one of the slide shafts 35 is applied to the other slide shaft 36.

[0059] The resilient members 47 and 48 may be attached to either one or both of the slide shafts 35 and 36, but in the illustrated embodiment, the resilient members 47 and 48 are attached to the other slide shaft 36. If the resilient members 47 and 48 are attached to the other slide shaft 36, the contact area between the slide shaft 36 and the slide hole 46 becomes smaller than that between the slide shaft 35 and the slide hole 45. As a result, the side of the slide shaft 35 with the larger contact area can bear a larger reaction force F than the side of the slide shaft 36 with the smaller contact area. As a result, with this structure, most of the reaction force F is borne by the slide shaft 35 and slide hole 45, which have a large contact area and high strength, thereby improving durability.

[0060] The above example shows the case where the resilient members 47, 48 are provided on the other slide shaft 36, but if the strength of the other slide shaft 36 is sufficient, the resilient members 47, 48 can be provided on one slide shaft 35 and the other slide shaft 36 can be left without the resilient members 47, 48, or both can be provided with the resilient members 47, 48.

[0061] (Second embodiment) 11 and 12 show a second embodiment of the present invention, in which knurled pieces 56, 57 are attached to the moving block 40 in a cantilevered manner. A bridge holding notch 44 is formed in one side surface 40a of the moving block 40, and the knurled pieces 56, 57 are rotatably attached to bridge holding shafts 52, 53 that are disposed in this bridge holding notch 44 and attached above and below to this bridge holding notch 44. The bridge holding shafts 52, 53 are attached to the bridge holding notch 44 with bridge holding bolts 54, 55. A parallel line CL2 passing through the center O of the knurled pieces 56 and 57 in the thickness direction is held shifted from the center line CL1 of the shank 10 by a shift width La toward the side surface 40a of the moving block 40. If the mounting block 20 is inverted with the moving block 40 attached, knurling can be performed on the chuck 80 and the corners S of the stepped portion in the same manner as in the first embodiment. [Explanation of symbols]

[0062] A: Self-aligning knurling device, CL1: Center line of shank, CL2: Parallel line passing through mounting block (midpoint between knurls), F: Reaction force, La: Deviation between parallel line and center line, Lb: Distance between parallel line and opposing surface of holding arm, L3: Distance from center line to side of arm on shank side, M: Tool post, O: Midpoint of knurl, S: Corner of stepped portion, W: Workpiece 10: shank, 10a: shank body, 10m: mounting surface, 11 and 12: shank side arm, 11a and 11b / 12a and 12b mounting surface, 13: insertion groove, 15 and 16: through hole, 20: mounting block, 21 and 22: mounting side piece, 23: mounting groove, 25 and 26: mounting portion, 25h and 26h: bolt hole, 25n and 26n: screw hole, 27: large diameter hole, 27a: O-ring storage groove, 28: O-ring, 29: fixing screw hole, 31 and 32: holding arm, 31h and 32h: holding hole, 33: holding groove, 35 and 36: slide shaft, 38: insertion hole, 40: moving block, 40a and 40b: Side, 40k: Base, 41: Plate, 42, 43, 43a: Wall for retaining bridge, 44: Notch for retaining bridge, 45, 46: Slide hole, 46a, 46b: Spring storage hole, 47, 48: Elastic material, 49: Long hole, 52, 53: Bridge retaining shaft, 54, 55: Bridge retaining bolt, 56, 57: Knurled bridge, 60: Fixing screw, 61: Head, 62: Leg, 63: Washer, 70, 71: Bolt, 80: Chuck, 81: Center

Claims

1. a shank 10 attached to a tool rest M; a mounting block 20 that is mounted on the shank 10 so as to be upside down about a center line CL1 extending in the longitudinal direction of the shank 10 as a rotation center; slide shafts 35 and 36 arranged side by side on the mounting block 20 in the vertical direction; a moving block 40 attached to the slide shafts 35 and 36 so as to be movable in the up and down direction; In the self-centering knurling device A, which is composed of knurling pieces 56 and 57 held above and below at the tip of the moving block 40, Elastic members 47 and 48 that elastically bias the moving block 40 from above and below are attached to at least one of the slide shafts 35 and 36, the knurling pieces 56 and 57 are held by the moving block 40 so that a parallel line CL2 that is parallel to the center line CL1 and passes through a midpoint O between the knurling pieces 56 and 57 deviates from the center line CL1 in the width direction of the knurling pieces 56 and 57.

2. One of the slide shafts 35 is installed at a position behind the knurled pieces 56 and 57 where the parallel line CL2 passes.

2. The self-centering knurling device according to claim 1, wherein the other slide shaft (36) is installed at a position away from the back of the knurling pieces (56, 57), and the resilient members (47, 48) are installed on the other slide shaft (36).

3. A plate portion 41 is provided on the back surface of the moving block 40 so as to protrude rearward, and a long hole 49 is drilled in the plate portion 41 so as to be parallel to the slide shafts 35 and 36.

3. The self-aligning knurling device according to claim 1, wherein the mounting block is provided with a fixing screw that is inserted into the long hole and fixes the plate portion to the mounting block.

4. The shank 10 is composed of a shank body 10a and shank-side arms 11 and 12 provided on the front surface of the shank body 10a. The mounting block 20 is provided with mounting side pieces 21 and 22 that are attached to the shank side arms 11 and 12, The mounting surfaces 11a, 11b and 12a, 12b to which the mounting pieces 21, 22 of the shank-side arms 11, 12 are attached are provided symmetrically with respect to the center line CL1 of the shank 10, The self-aligning knurling device according to claim 1 or 2, characterized in that the attachment portions 25 and 26 of the attachment side pieces 21 and 22 to the shank side arms 11 and 12 pass through the midpoint O between the knurling pieces 56 and 57 and are arranged symmetrically in a front view with respect to a parallel line CL2 extending parallel to the center line CL1.

5. A piece-holding notch 44 is provided in the top end of the moving block 40 in a vertical direction in accordance with the parallel line CL2, and piece-holding wall surfaces 42 and 43 for holding the knurled pieces 56 and 57 are formed on both sides of the piece-holding notch 44.

3. The self-centering knurling device according to claim 1, wherein one of the piece-holding wall portions (42) is thinner in width than the other piece-holding wall portion (43).

6. 3. The self-aligning knurling device according to claim 1, wherein a piece-holding notch 44 is recessed in one of the side surfaces 40a (40b) of the tip of the moving block 40 in alignment with the parallel line CL2, and a piece-holding wall surface 43a that cantilevers the knurled pieces 56 and 57 is formed in the piece-holding notch 44.

Images