A slotting tool

Abstract: This slotting tool 1 continuously slots a work W by moving the work W disposed between a punch 3 and a die 7. The punch 3 comprises a shear angle α formed at an end of the punch 3 and a toe portion 3A for shear the work. The die 7 comprises a starting blade 9A under the toe portion 3A and a scrap cutting blade 15 below the toe portion 3A. When the punch 3 descends, the toe portion 3A and the starting blade 9A shear the work W for starting the slotting operation. The punch 3 further descents and slot the work W. After the punch 3 ascend and the work W is moved, the slotted scrap is inserted into a scrap path 17, and the slotted scrap is cut off by means of the toe portion 3A of the punch 3 and the scrap cutting blade 15.

Description: Field of the Invention The present invention relates to a slotting tool for use in slotting a work as defined in the preamble of claim 1. Such a slotting tool is known from EP-A-0 639 413. Another cutting device is known from US-A-5,400,682. This cutting device, however, does not have a scrap cutting blade for cutting scrap to length when a work is continuously and repeatedly fed by a predetermined pitch. Accordingly, the residue will still be connected to the work and will contacting parts of the die thus impeding the slotting of the work. Description of the Related Art A slotting tool of the related art is constructed in a manner such that a toe of a punch does not cooperate with die to preliminarily punch out a work. The slotting tool slots the work by means of a slotting portion of the punch and the die, and punch out for cutting off the slotted scrap from the work by means of a heel portion of the punch and the die. Therefore, the slotting tool does not work on a slotting starting position in the work. In this connection, prior to slot the work by the slotting tool of the related art, it is required to prepare an auxiliary and extra hole which locates in an extension line of the slotted hole(slit) required and overlaps with the slotted hole required. On the other hand, in another type of slotting tool, a repeated slotting operation is required up to a hole preliminarily and previously punched for slotting because incomplete slotting scrap is left on a work on a final stage of the continuous slotting operation, notwithstanding the slotting tool does not require to prepare the auxiliary and extra hole. Therefore, in the type of slotting tool, the auxiliary and extra hole which locates in an extension line of the slotted hole required and overlaps with the slotted hole required must be punched at a final and terminating slotting position, prior to slot the work by the slotting tool. Therefore, the slotting operations are augmented and complicated so that the cost of the slotting operations are grown up. Furthermore, when a micro-joint portion on a work which remains and is formed on the work by a slotted hole and another slotted hole near to the former slotted hole is required, the micro-joint portion does not remain and is not formed on the work because of the auxiliary and extra hole. In addition, an unevenness occurs in the slotted hole which is preliminarily punched and is slotted, thereby the accuracy of the hole is lowered. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and provide a slotting tool which is able to start the slotting operation from any position without a preliminarily punched hole prior to the slotting operation. It is another object of the invention to provide a slotting tool which is able to terminate the slotting operation at any position without a auxiliary hole prior to the slotting operation. It is still another object of the invention to provide a slotting tool which is able to allow selecting slotting lengths freely. It is further object of the invention to provide a slotting tool in which the scrap cutting blade is able to avoid to be worn by the tip of the slotted scrap. To achieve the above object, the present invention provides a slotting tool as defined in claim 1. Preferred embodiments are defined in the dependent claims. The slotting tool further comprising an ejector vertically movable disposed below the toe portion for cooperating with the toe portion to push the slotted scrap and for ejecting the slotted scrap and a backup plate fixed to the die for supporting the scrap cutting blade and the ejector. It is desirable that the scrap cutting blade has rounded portions on the bottom end portion thereof and an inclined face to be inclined when the slotted scrap push the scrap cutting blade and that the scrap cutting blade is biased downwardly by a bias means located between the backup plate and the die. Thus, when a work is placed on the die, a position of the work in which slotting is to be started is made to coincide with the toe portion and the slotting potion of the punch and then the punch is descent to start the slotting. At this time, the punch is descent at such a stroke that the punch does not wholly bite the work. After the punch ascend, the work is fed by a distance less than a predetermined slotting length. Then the slotted scrap is inserted into the scrap path located under the starting blade. Next, the punch is further descent only slightly such that the slotting scrap in the scrap path is cut off by the toe portion of the punch and the scrap cutting blade. The above operation is repeated such that the work is moved and then is punched each time. As the press stroke for the final cutting is set to be larger than the previous ones, in a final slotting operation, the heel portion of the punch is descent so that the slotted scrap is wholly cut off by the heel portion of the punch and the terminating blade, thereby the slotting operation is completed. As a result, a preliminary and previous hole in the starting and terminating points becomes unnecessary so that an occurrence of an unevenness on a slotting surface can be avoided. Further the slotting length can be selected as desired. During the punch is ascending upwardly after the toe portion has cooperated to cut off the slotted scrap, the scrap cutting blade is swung and inclined so that the scrap cutting blade is able to avoid to be jammed with the tip of the slotted scrap. As the result, the scrap cutting blade is able to avoid to be worn by the tip of the slotted scrap, thereby the life cycle of the slotting tool is elongated. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view of a slotting tool according to the present invention. Fig. 2 is a sectional view of the slotting tool, taken along the line II-II in Fig. 1. Fig. 3 is a partial front view of the slotting tool for explaining a slotting operation on a work by a toe portion of a punch. Fig. 4 is a partial front view of the slotting tool for explaining a slotting operation on a work by a slotting portion of a punch. Fig. 5 is a partial front view of the slotting tool for explaining the slotted scrap is inserted to a scrap path. Fig. 6 is a partial front view of the slotting tool for explaining the slotted scrap is cut off by a scrap cutting blade. Fig. 7 is a partial front view of the slotting tool for explaining the slotted scrap is inserted to the scrap path. Fig. 8 is a partial front view of the slotting tool for explaining the slotted scrap is completely punched out by a heel portion of the punch. Fig. 9 is a partial front view of the slotting tool for explaining the completely punched out scrap is dropped downwardly. Fig. 10 is a plan view of a work processed by the slotting operation of the present invention. Fig. 11 is an enlarged view of a micro-joint portion shown in Fig. 10. Fig. 12 is an enlarged view of a micro-joint portion shown in Fig. 10. Fig. 13 is an enlarged front view of a scrap cutting blade shown as a second embodiment of the present invention. Fig. 14 is an enlarged side view of a scrap cutting blade shown in Fig. 13. Fig. 15 is a partial front view of the slotting tool for explaining the slotted scrap is cut off by the scrap cutting blade of the second embodiment. Fig. 16 is a partial front view of the slotting tool for explaining the scrap cutting blade is inclined from an original attitude to avoid the jamming with the slotted scrap when the slotted scrap is pushed upwardly by an ejector. Fig. 17 is a partial front view of the slotting tool for explaining the scrap cutting blade is in the original attitude. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in details with reference to the accompanying drawings. Referring to Figs. 1 and 2, a slotting tool 1 comprises a punch 3 vertically movable and a die unit 5. The punch 3 is so constructed that its stroke can be set freely by means of a well known hydraulic cylinder or the like. The punch 3 has a shear angle α at its bottom end portion so that the heel portion 3B of the punch 3 does not bite completely into the work to be slotted when the bottom stroke of the punch 3 is controlledly vertically driven. The die unit 5 comprises a die 7 which has a blade 9 on a top surface thereof, the blade 9 including a starting blade 9A, side blades 9C and a terminating blade 9B. The starting blade 9A cooperates with a toe portion 3A of the punch 3 to shear the work to be slotted as a starting stage of the slotting operation. The side blades 9C cooperate with a slotting portion 3C of the punch 3 to slot the work continuously as a middle stage of the slotting operation. The terminating blade 9B cooperates with a heel portion 3B of the punch 3 to punch out the work to be slotted as a final and terminating stage of the slotting operation so that the slotted scrap is removed and dropped from the work. A backup plate 7A is provided on a bottom of the die 7. A hole 7B is formed almost in the center of the backup plate 7A. In this hole 7B, an ejector 11 is provided so as to be movable vertically and further urged upward by springs 13. The ejector 11 may be so constructed as to be moved vertically by air cylinders or the like. In this case, the ejector 11 is moved vertically in synchronism with motions of the punch 3. A scrap cutting blade 15 is disposed such that it is in contact with the ejector 11 with a slightly narrow shearing gap therebetween. The backup plate 7A supports the ejector 11 and the scrap cutting blade 15. The construction described above is not restricted to the embodiment but it can be constructed in such a manner that each of the ejector 11 and the scrap cutting blade 15 is supported by a working table of a punching press or by a turret of a turret punching press. Fig. 2 is a sectional view of Fig. 1 taken along the line II-II, showing that a work W is placed on the die 7. The side blades 9C of the die 7 are disposed on the right and left sides so as to oppose each other, so that the punch 3 and the side blades 9C cooperate with each other to slot continuously the work when the punch (not shown) descends. A scrap path 17 is formed below the starting blade9A to receive the slotted scrap. As shown in Fig. 2, the scrap cutting blade 15 is located in the scrap path 17 of the die 7. The scrap cutting blade 15 cuts a slotting scrap to a predetermined length and discharges it in cooperation with the toe portion 3A of the punch 3 when the punch 3 descends deeply to the lower bottom point. In slotting operation, a stripper plate 19 and a punch guide 21 are forced by a flange 23 so that they descend. Then, the stripper plate 19 makes contact with the die 7 through the work W. After that, the stripper plate 19 is urged downward by means of a lifter spring 25 such that the work W is firmly grasped. After that, only the punch 3 continues to descend through the punch guide 21 and further descends against an urging force of a stripper spring 27 so as to cut the work W in cooperation with the die 7. Referring now to Figs. 3, 4, 5, 6, 7, 8 and 9, the operation of the slotting on the work W is explained more detail. The work W is placed on a top surface of the die 7. In this stage, the punch 3, the stripper plate 19 and the punch guide 21 are ascended so that they are not in contact with the work W. Next, as shown in Fig. 4, the punch guide 21 and the stripper plate 19 descend and grasp the work W in cooperation with the die 7. Successively, the toe portion 3A of the punch 3 descends to shear the work W in cooperation with the starting blade 9A ,and the slotting portion 3C of the punch 3 descends to slot the work W in cooperation with the side blades 9C (not shown here because they are hidden by the punch 3). As shown in Fig. 4, the punching of slitting can be started from any position in the work W. Therefore, a preliminary hole as a auxiliary and extra hole to be punched out in a previous stage is not required. At this time, the slotted scrap of the work W is bent downwardly at an angle almost equal to the shear angle α of the punch 3. As shown in Fig. 4, the punch 3 is made to descend with small strokes such that the work W is punched through by cooperation with the punch 3, the starting blade 9A of the die 7 and the side blades 9C thereof (not shown because they are hidden by the punch 3). At this time, the heel portion 3B of the punch 3 remains above the terminating blade 9B such that it does not incise the work W. After the punch 3, punch guide 21 and the stripper plate 19 ascend as shown in Fig.5, the work W is fed at a smaller distance than a predetermined cutting length in a direction of the arrow B-B or to the left in Fig. 5. A tip portion of the slotted scrap enters the scrap path 17. As shown in Fig. 6, the punch 3 grasps the work W in cooperation with the ejector 11 and further descends, so that the toe portion 3A of the punch 3 cuts off the tip portion WA of the slotted scrap in cooperation with the scrap cutting blade 15. The tip portion WA of the slotted scrap is dropped downwardly through the scrap path 17. At the same time, the work W is slotted further by means of the slotting portion 3C and the slide blades 9C. As shown in Fig. 7, after the punch 3, punch guide 21 and the stripper plate 19 ascend, the work W is fed further by only the cutting length in the direction of the arrow B-B or to the left in Fig. 7. The next tip portion of the slotted scrap enters the scrap path 17. At the same time, a portion to be ripped newly of the work W advances below the slitting portion 3C of the punch 3. As shown in Fig. 6, the punch 3 descends again slightly deep and slots the work W, so that the slotted portion of the work W is elongated. Then the slitting operations as shown in Fig. 5, 6, and 7, are continuously repeated. Referring to Figs. 8, 9, when the work W is ripped at a final end thereof, the punch 3 is made to descend to the bottommost such that the heel portion 3B of the punch 3 cooperates with the terminating blade 9B to cut off the. The slotting scrap is also cut off by means of the toe portion 3A and the scrap cutting blade 15 and separated as the scrap WA and a scrap WB. The scrap WB is dropped downwardly through the hole 7B of the die 7. Then, the slotting operation is terminated. As described above, by the operations shown in Figs. 3 to 9, as the first stage of the slotting operation, the work W is sheared by the starting blade 9A and the tip portion of the slotted scrap to be cut off enters the scrap path 17. Thus, there does not occur such a case in which the slotting scrap and protective vinyl covering the work surface jump out upward to interrupt the continuous slotting operation as in the related art. Further, air blow for removing the scattered slotting scrap WA and the vinyl becomes unnecessary. Still further, it is not necessary to preliminarily make a starting hole. At the final punching stage after slitting operation is repeated up to the predetermined cutting length, the final end portion is cut and separated in cooperation with the terminating blade 9B and the punch 3 with the press stroke set to a larger one as shown in Figs. 8, 9. Thus, it is not necessary to preliminarily make a auxiliary and extra hole in the final end portion of the slotted hole. Fig. 10 shows a plan view of the work W processed by means of the slotting tool according to the present invention. A portion A indicates the micro-joint portion. Fig. 11 is an enlarged view of the micro-joint portion of Fig. 10. Fig. 12 shows part of Fig. 11 indicating that slotting operation can be started from a cross-hatched part in the vicinity of the micro-joint A because a pretreatment is not necessary, so that there occurs no unevenness on its slotting surface. As understood by the description of the embodiments, the slotting tool according to the present invention has eliminated a necessity of the auxiliary holes in the starting position and terminating position on a preceding stage and a possibility of scattering of slotted scraps. Thus, interruptions of slotting work for cleaning or the like are eliminated and further grinding work on post stage has become unnecessary because there is not an unevenness on the slotting surface. Consequently, the slotting process is simplified and further an accuracy in finished products can be improved tremendously. Still further it is possible to determine the slotting length as desired. Referring now to Figs. 13 to 17, the second embodiment is explained hereinafter. In the embodiment, the scrap cutting blade is improved as shown in Fig. 13. The scrap cutting blade 15 is formed with rounded portions 15A on the bottom end portion. Furthermore, the scrap cutting blade 15 is formed with a inclined face 15B of angle β as shown in Fig. 13. The scrap cutting blade 15 is biased downwardly by means of elastic members 29 as springs which are mounted in the die 7. In this connection, when the punch 3 ascend upwardly after the toe portion 3A has cooperated to cut off the slotted scrap(Fig.15), the tip portion of the slotted scrap is slightly extended and push the scrap cutting blade 15. Then the scrap cutting blade 15 is swung and inclined in counter-clockwise in Fig. 16. The attitude of the scrap cutting blade 15 inclined is shown by a dotted line in Fig. 13. The inclination angle is β which equals to the inclination angle of the inclined face 15B. Furthermore, the scrap cutting blade 15 is swung and inclined around the center of the curvature of the rounded portion 15A nearer the inclined face 15B. The slotted scrap is moved upwardly by means of the ejector 11 without jamming with the scrap cutting blade 15. Therefore, the scrap cutting blade 15 is able to avoid to be worn by the tip of the slotted scrap, thereby the life cycle of the slotting tool is elongated. As the result of use of the improved slotting tool, tipping of the scrap cutting blade 15 does not occur under the condition that the work W is stainless steel with 1.5 and 2.0 mm thickness, the scrap cutting blade 15 is made of alloy tool steel for hot dies (SKD-11) with Rockwell hardness 56 , and testing amounts (hits) are 10,000 times. The present invention is not restricted to the above described embodiments but can be embodied in other forms by appropriate modification, within the scope of the appended claims.

Claims: A slotting tool for slotting a work (W), comprising: a punch (3) having a toe portion (3A) and a heel portion (3B) at lower portion thereof, the heel portion (3B) locates higher than the toe portion (3A), said punch (3) defining a slotting portion; a die (7) having side blades (9C) for cooperation with the slotting portion to slot the work (W) and a determinating blade (9B) for cooperating with the heel portion (3B) to cut off the slotted scrap and a scrap cutting blade for cooperating with the toe portion (3A) to cut off a tip portion of the slotted scrap; characterized in that said die (7) furthermore has a starting blade (9A) for cooperating with the toe portion (3A) to shear the work (W) and that said scrap cutting blade (15) is disposed below said starting blade (9A) defining between the scrap cutting blade (15) and the starting blade (9A) a scrap path (17) for receiving the tip portion of the slotted scrap. A slotting tool as claimed in claim 1, further comprising: an ejector (11) vertically movable disposed below the toe portion (3A) for cooperating with the toe portion (3A) to push the slotted scrap and for ejecting the slotted scrap. A slotting tool as claimed in claim 2, further comprising: a backup plate (7A) fixed to the die (7) for supporting to the scrap cutting blade (15) and the ejector (11). A slotting tool as claimed in claims 1 or 2, wherein the scrap cutting blade (15) has rounded portions on the bottom end portion thereof and an inclined face so that the scrap cutting blade (15) is inclined when the slotted scrap pushes the scrap cutting blade (15). A slotting tool as claimed in claim 4, further comprising: a bias means located between a backup plate (7A) and the die (7).

Inventors: SEKI MASAYUKI, SEKI, MASAYUKI
Applicants: AMADA CO LTD, AMADA COMPANY, LIMITED
Application year: 1997
Main classification: B21D28
IPC codes: B21D28, B23D31, B23D27