MXPA96005201A - Perfor - Google Patents

Abstract

A replacement of the cylindrical blades is facilitated. Even when there is a slight displacement in the guide surfaces of a slide, the displacement is not detrimentally affected with respect to the displacement of a tip end of each cylindrical blade in order to do without a pad, perforating the paper with a lower blade and the tip end of the cylindrical blade. A blade holder (28) in which the cylindrical blades (14) are inserted through the through holes (25) and (26) formed in an upper horizontal portion (22) and a lower horizontal portion (23). Therefore, it is possible to replace the cylindrical blades (14) by simple steps to insert and attract the blade holder (28). Also, since the upward and downward movement of the cylindrical blade (14) is guided independently of the guide portion of the slide (10) by the through hole (25) formed in the upper horizontal portion (22), it is allows movement in the guide portion of the slide (10). Then, since an oscillating movement of the cylindrical blade (14) and the lowering position of the tip end of the blade is prevented, it is accurately determined it is possible to cut and perforate the paper between the tip end of the blade (14). cylindrical and the lower blade (27) to do without a cushion

Description

"DRILL" BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to an improvement in a drilling machine. 2. DESCRIPTION OF THE RELATED TECHNIQUE An example of a conventional punch will now be described with reference to Figures 20 and 21 in Figure 21, a head member 1 is fixed to a base 2. A guide member 3 is placed on the head member 1 and fixed at the same intermediate bolts 4. A proximal end of a support member 5 is rotatably mounted within the guide member 3 by a pin 6. A proximal end of an arm 8 is rotatably mounted on the other end of the support member 5 by means of the pin 7. A guide projection 301 is provided in the guide member 3. A guide space 9 is formed between the guide projection 301 and a front face 101 of the head member 1. A guide slot 11 of a slide 10 engages with the guide projection 301. A guide flange 12 is engaged with the guide space 9 so that the slide 10 can be movable in the vertical direction. The slide 10 is connected to the arm 8 by a pin 13. The arm 8 is rotated about a pin 7 in directions indicated by a double-headed arrow. As a result, the slide 10 moves up and down in the vertical direction. A cylindrical blade 14 is detachably provided at a lower end of the slider 10. A pad 16 is provided on a paper-laying surface 15, against which the tip end of the cylindrical blade 14 will abut. As shown in Figure 20, the assembly operation of the cylindrical blade 14 is achieved by fixing the cylindrical blade 14 in the slider 10 by inserting a head portion in the cylindrical blade 14 into an insertion hole 19, without any displacement, screwing a stop screw 17 and snapping the tip end of the stop screw 17 into a concave slot 18. Also, essentially the same technology is disclosed in the Japanese Utility Model Publication Number Sho-39040. The conventional drilling machine described above suffers from the following defects, since the cylindrical blade attachment depends on the manner of retaining the fit between the insertion hole and the head portion of the cylindrical blade, and the guide portion of the slide. inserting the head portion of the cylindrical blade into the insertion hole, without any displacement so that the cylindrical blade does not move when the paper is perforated. When the cutting operation of the cylindrical blade is degraded or it is desired to change a size of the hole to be formed through the paper, it is necessary to exchange the cylindrical blades. During the exchange of the blades, it is necessary to remove or remove the stop screw and subsequently attract the cylindrical blade from the insertion hole, then insert the cylindrical blade back into the insertion hole and then fix the cylindrical blade by the stop screw . The exchange of the cylindrical cuchilas is annoying. Also, when inserting a new cylindrical blade into the insertion hole, there is no displacement in the coupling between the cylindrical blade and the insertion hole, and it is impossible to carry out the insertion while observing the insertion hole. Accordingly, it is difficult to insert the head portion of the cylindrical blade into the insertion hole. Also, in the case where a large number of holes must be formed in the paper, the number of the cylindrical blades is increased. Therefore, it is annoying to replace the cylindrical blades. This point should be improved for use as an office instrument. Also, since the cylindrical blade is essentially supported by the slide this structure has the points that must be improved in the following manner. The case where a large stack of paper should be punched, the arm must be pressed down by a considerably large force. This downward pressure is applied directly to the slide. Accordingly, if there is any displacement in the guide portion of the slide, in the part where the slide is pressed down, the slide must be made to oscillate. The oscillation movement is transmitted to the cylindrical blade. In the worst circumstances, the cylindrical blade would be damaged. Therefore in order to eliminate the displacement of the slide, it is necessary to carry out a high precision machining for the guide portion of the slide. The manufacturing cost for this would be increased disadvantageously. Likewise, the displacement of the slide and the curvature of the cylindrical blade causes the displacement of the drop position of the cylindrical blade tip. Therefore, it is difficult to insert the tip of the cylindrical blade towards the lower blade to carry out the cutting operation between the lower blade and the tip. It is almost impossible also to adopt a system in which a lower blade is provided. Accordingly, a pad is provided in the downward position of the tip, and the tip of the cylindrical blade is pressed against the pad. Even when the tip position is shifted to a certain degree, the paper can be punched well. Since the pad is new, the cut can be done well. However, when the pad is subjected to defects, even if the tip of the cylindrical blade does not wear out but is sharp, the pads should be replaced. Due to this reason, the pads should be replaced frequently and this would be annoying. This must be improved for a routine operation of the office instrument COMPENDIUM OF THE INVENTION An object of the present invention is to provide a drilling machine in which the replacement of the cylindrical blades is simplified, even when there is a slight displacement in the guide surfaces of a slide, the displacement does not detrimentally affect a displacement of the tip end of each one. Cylindrical blade, and the drilling is performed by a lower blade tip end to thus do without a pad. According to a first aspect of the invention, a drilling machine is provided in which a head portion of a blade is detachably retained in a slide that moves up and down in a vertical direction, characterized in that a blade holder having a space for the insertion of the paper, the space is in the form of a "U" in lateral elevation defined by an upper horizontal portion, a lower horizontal portion and a vertical portion through the holes that are formed in the upper horizontal portion and the portion lower horizontal so that the cylindrical blade traverses the space, the blade holder into which the cylindrical blade has been inserted into the through holes is inserted and is attracted below the slide, and the head portion of the blade projecting in the upper horizontal portion it is retained by the slide. According to a second aspect of the invention, a length of the through hole formed in the upper horizontal portion of the blade holder is elongated, namely, larger than a length of the diameter of the through hole so that the cylindrical blade is not oscillated, and the lower blade is formed in the through hole formed in the lower horizontal portion. According to a third aspect of the invention, a recessed groove is formed in a circumferential surface of the head portion of the cylindrical blade, and a convex surface coupled with the recessed groove is formed in a retention portion of the slide for the cylindrical blade. According to a fourth aspect of the invention, a convex flange portion is formed on a circumferential surface of the head portion of the cylindrical blade and a concave surface coupled with the beveled convex portion is formed in a retention portion of the slider for the cylindrical blade. According to a fifth aspect of the invention, a recessed groove is formed in the circumferential portion of the cylindrical blade, an insertion hole into which a head portion of the cylindrical blade is provided in a slider retention position for the cylindrical blade, and a screw hole is provided so that a tip end of a screw is engaged with the recessed slot of the inserted head portion within the insertion hole.

An explanation was provided of the manner in which the tasks are solved by the structure described above. First, in accordance with the first aspect of the invention, by the simple steps in which the space defined by the upper horizontal portion, the lower horizontal portion and the vertical portion to form the "U" shaped lateral elevation for the insertion of the paper, is crossed by the cylindrical blade and the blade holder that has the through holes formed in the upper horizontal portion and the lower horizontal portion through which the cylindrical blade passes, is inserted and is attracted below the slide and is possible to replace the cylindrical blades. Also, the head portion of the blade projecting towards the upper horizontal portion of the blade holder is retained in the slide and the up and down movement of the cylindrical blade is guided by the through hole formed in the upper horizontal portion of the blade holder. , regardless of the guide portions of the slide. The oscillation of the cylindrical blade is avoided and the lowering position of the blade tip is accurately determined. In accordance with a second aspect of the invention, the length of the through hole formed in the upper horizontal portion of the blade holder is lengthened, namely, it becomes greater than a length of the diameter of the through hole so that no oscillatory movement of the cylindrical blade is generated, the guide for movement Up and down of the cylindrical blade is more positive, the oscillating movement of the cylindrical blade is more effectively removed to keep the downward position of the tip end of the blade constant, the lower blade provides in the hole formed in the lower horizontal portion, and the tip end of the cylindrical blade that is lowered to an exact position is inserted into the lower blade with high precision to cut and puncture the paper between the lower blade and the tip end of the lower blade. the cylindrical blade. According to the third aspect of the invention, since the prevention of the oscillatory movement of the cylindrical blade does not depend on the guide portions of the slide, simply forming the recess groove in the circumferential surface of the head portion of the blade cylindrical, forming the convex surface, that is, to be coupled by the recess slot, in the retention portion of the slide for the cylindrical blade and inserting and attracting the blade holder below the slider in engagement between the recess slot and the convex surface, it is possible to retain the head portion of the cylindrical blade in the slide. According to the fourth aspect of the invention, since the prevention of the oscillatory movement of the cylindrical blade does not depend on the guide portions of the slide, simply forming the flanged projection on the circumferential surface of the head portion of the cylindrical blade , forming the concave surface, that is, the coupling with the flanged projection, in the retention portion of the slide for the cylindrical blade, inserting and drawing the blade holder under the slide in the coupling between the recess slots and the recess. convex surface, it is possible to retain the head portion of the cylindrical blade in the slide. According to the fifth aspect of the invention, the insertion hole into which the head portion of the cylindrical blade is provided in the retention portion of the slider for the cylindrical blade, a screw hole with which is coupled the tip end of the screw, is provided in the recess formed in the head portion of the cylindrical blade that is inserted into the insertion hole, the holder having the through hole into which the cylindrical blade is inserted, is placed below of the slide, the head portion of the cylindrical blade is inserted into the insertion hole by lowering the arm, the tip end of the screw fits into the recessed slot of the head portion and the head portion of the cylindrical blade is retained in the slide. The embodiment of the invention defined in the first aspect of the invention is as follows: According to the first aspect of the invention, in Figure 1 there is provided a drilling machine in which a head portion of a blade 14 is retained detachably in a slide 10 that moves up and down in a vertical direction. A blade holder 28 having a space for inserting the paper. The space is U-shaped in lateral elevation defined with an upper horizontal portion 22, a lower horizontal portion 23 and a vertical portion 24. The through holes 25 and 26 are formed in the upper horizontal portion 22 and the lower horizontal portion 23 so that a cylindrical blade 14 traverses the space. The blade holder 28 in which the blade 14 is inserted into the through holes 25 and 26 is inserted and is attracted below the slide 10 and a head portion of the cylindrical blade 14 projecting into the horizontal portion 22 The upper part of the knife holder 28 is retained by the slide 10. The embodiment of the invention is defined by the second aspect of the invention is as follows: In Figure 4, a length H2 of the through hole 25 formed in the upper horizontal portion 22 of the blade holder 28 is lengthened to be greater than the diameter diameter of the through hole, and a lower blade 27 is formed in the through hole 26 formed in the horizontal portion 23 lower. The embodiment of the invention, defined by the third aspect of the invention is the following: In Figure 1, a recessed slot 20 is formed in a circumferential surface of the head portion of the cylindrical blade 14, and a convex surface 21 coupled with the recessed slot 20 formed in a retention portion of the slider 10 for the cylindrical blade 14, as shown in Figures 10 and 12. The embodiment of the invention defined by the fourth aspect of the invention is as follows: beaded convex portion is formed on a circumferential surface of the head portion of the cylindrical blade 14 instead of the recessed slot 20, and a concave surface is formed in a retention portion of the slider 10 for the cylindrical blade 14 instead of the convex surface 21. In this case as well, it is possible to retain the cylindrical blade 14 at the lower end of the slider 10. The embodiment of the invention defined by the fifth aspect of the invention is the following: In Figure 2, a recess 20 is formed which is recessed in FIG. a circumferential portion of the cylindrical blade 14, an insertion hole 32 within which a head portion of the cylindrical blade 14 is provided in a retention portion of the slider 10 for the cylindrical blade 14, and a hole 33 of screw so that the tip end of the screw 31 is engaged with the slot 20 recessed from the head portion inserted in the insertion hole BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: Figure 1 is a longitudinal sectional view in side elevation showing a main part of a punch that is provided with a blade holder in accordance with an embodiment of the invention; Figure 2 is a longitudinal sectional view in side elevation showing a main part of a drill that is provided with a slider according to another embodiment of the invention; Figure 3 is a plan view showing a blade holder shown in Figures 1 and 2; Figure 4 is a longitudinal sectional view taken along line X-X of Figure 3; Figure 5 is a front view as seen from the right side of Figure 4; Figure 6 is a bottom view of Figure 3; Figures 7A, 7B and 7C are views showing the order of the steps to replace the cylindrical blades in Figure 1; Figure 8 is a view showing an operating condition of the punch shown in Figure 1; Figure 9 is a plan view showing the slide shown in Figures 1 and 2; Figure 10 is a side elevation view showing the slide shown in Figures 1 and 2; Figure 11 is a longitudinal sectional view of the slide shown in Figure 1, taken along the line Y - Y of Figure 9; Figure 12 is a rear view showing the slide shown in Figures 1 and 2; Figure 13 is a front view of Figure 11; Figure 14 is a partially fragmentary plan view of Figures 1 and 2; Figure 15 is a longitudinal sectional view of the slide shown in Figure 2 which is taken along the line Y - Y of Figure 9; Figure 16 is a front view of Figure 15; Figure 17 is a plan view showing the guide member shown in Figures 1 and 2; Figure 18 is a side elevation view of Figure 17; Figure 19 is a perspective view showing the entire drill shown in Figure 2; Figure 20 is a longitudinal sectional view showing a main part of a conventional drill; and Figure 21 is a partially fragmentary longitudinal sectional view showing the entire state of the conventional drill.

DESCRIPTION OF THE PREFERRED MODALITIES The present invention will now be described by way of example with reference to the accompanying drawings. A contour of a punch will now be described with reference to Figure 19. Each head member 1 is mounted on a base 2. An arm 8 is rotatably mounted on a support member 5 (Figures 1 and 2) incorporated in member 1 of head A blade holder 28 is provided retractable / projectingly in a "U" shaped portion of the head member 1. The knife holder 28 is fixed under the condition that the lower horizontal portion 23 (Figures 1 and 2) is inserted into a recessed portion 151 formed in a surface 15 for loading paper. In this mode, for example, three perforated holes are shown. The number of pierced needles can be two, four or any other number. Each component will now be described in detail in order. The knife holder 28 will now be described. In Figure 4, the blade holder 28 is U-shaped in lateral elevation. The knife holder 28 is composed of an upper horizontal portion 22, a portion. 23 horizontal bottom and a vertical portion 24. The through holes 25 and 26 are formed in the upper horizontal portion 22 and the lower horizontal portion 23, respectively, for insertion of the cylindrical blades 14. A diameter of each through hole 25 is selected so that a static engagement is achieved without any displacement between the through hole 25 and the blade 14 to be inserted into the through hole 25. The vertical movement of the cylindrical blade 14 can be well guided. An extension 30 is provided to extend a length H2 of the through hole 25. The length H2 is selected so that the vertical movement of the cylindrical blade 14 is positively carried out in the cylindrical blade 14 does not vibrate against the cutting resistance of the paper. Thus, the position of the tip of the cylindrical blade 14 does not move. In this embodiment, the length H2 is approximately twice as large as the diameter of the through hole 25. It is preferred to select the length H2, at least longer than the diameter of the through hole. A lower blade 27 is formed around a edge portion of the through hole 26. The lower blade 27 is removed with a cylindrical blade 14 with high precision to cut the paper. Figure 3 is a plan view showing the blade holder 28. Ribs 29 are provided in the blade holder 28. A dimension Wl between the outer walls of the ribs 29 is essentially equal to the dimension W2 internal to the head member 1, so that the ribs 29 function as a guide mimebra when the ribs 29 engage the head member 1. As shown in Figures 3, 4 and 5, positioning surfaces 241 are provided in the vertical portion 24. The positioning surfaces 241 are placed in contact with the lower portion 102 of the U-shaped cutting portion of the head member 1, and an axis of the through hole 25 is made to coincide with an axis of the insertion hole 32 (FIG. Figure 2) by a guide action of the ribs 29. As shown in Figures 3 and 5, the guide surface 221 is provided in the upper horizontal portion 22. When the guide surface 221 is in sliding contact with the upper horizontal portion 103 of the "U" shaped cutting portion of the head member 1, it is in this way to restrict the upward movement of the knife holder 28. Therefore, , the blade holder 28 is placed retractably and projectingly relative to the head member 1 by the ribs 29, the positioning surfaces 241 and the guide surfaces 221. Also, as shown in Figure 4, in the knife holder 28, the paper insertion portion having a "U" shape in lateral elevation and the height Hl is formed by the upper horizontal portion 22, the lower horizontal portion 23 and the vertical portion 24. The knife holder 28 is reinforced by the ribs 29 so that the upper horizontal portion 22 and the lower horizontal portion 23 are integral to have stiffness. As shown in Figures 4 and 6, the through hole 26 is formed in the lower horizontal portion 23. The lower blade 27 is formed on the edge of the through hole 26. The lower blade 27 and the tip of the cylindrical blade 14 are coupled with high precision and the paper is cut between the lower blade 27 and the tip to form a hole in the paper. The slide 10 will now be described. Figure 9 is a plan view of the slider 10. The guide slots 11 and the guide tabs 12 are provided in the slider 10. A slit 34 is formed in the central portion of the slider 10 for the insertion of the arm 8 A width of the guide flange 12 is greater than a width W5 between the guide surfaces 36 and the stepped portion of W6 is shaped so that a guide member 3 (Figures 1 and 2) to be described later can be coupled. . A width W7 between the guide surfaces 37 of the support member is smaller than a width W5 of the guide surfaces 36 so that the support member 3 does not interfere with the guide surfaces 36 by the stepped portions W8.

As shown in Figure 10, a pin hole 35 through which the pin 13 shown in Figures 1 and 2 is inserted is formed to pass between the guide surfaces 36. Also, a portion 38 of the slide guide 10. Namely provided, as shown in Figures 11 and 12, the cut chips of the paper by blade 14 cylindrical (Figures 1 and 2) causes pass through the interior of the cylindrical blade 14 and discharged from the chip discharge hole 40 cut as indicated by the arrow to be unloaded along the cut knife guide surface 39. When the chips are discharged, the chips are guided by the cut knife guide portion 38 so that the chips are dispersed outwardly. Also, in the embodiment shown, as shown in Figures 11 and 13, a convex surface 21 is provided in the retention portion of the cylindrical blade 14 to project toward the surface of the open "U" shaped portion in its front face so that the recessed slot 20 formed in the head portion of the cylindrical blade 14 shown in Figure 1 fits into the convex surface 21. Also, the convex surface 21 may be concave and the recessed portion 20 formed in the head portion of the cylindrical blade 14 may be convex so that the concave portion and the convex portion may be coupled with one another. Figures 15 and 16 show another embodiment of the invention. An insertion hole 32 is formed in the retention portion of the cylindrical blade 14. A diameter of the insertion hole 32 is greater than a diameter of the head portion of the cylindrical blade 14. In this case, a slight displacement can be allowed between the insertion hole 32 and the head portion to be inserted into the insertion hole 32. A screw hole 33 is provided to pass through the insertion hole 32. The other structure is the same as that shown in Figures 9 to 12. The same reference numbers have been used to indicate the same member. Therefore, duplicating the explanation of the common parts will be omitted. The guide member 3 will now be described. In Figure 17, the plan view of the guide member 3 is "U" shaped. The open portion is provided with projections 301 guide to engage with the grooves 11 guide (Figure 9) of the slider 10. Also, a width W9 bottom is graded so that the member 3 guide can be coupled with the portion it has the width W5 between the guide surfaces 36 shown in Figure 9. An outer width W10 is graduated so that the guide member 3 can be coupled with the portion having the internal width W2 of the head member 1 shown in FIG. Figure 3. As shown in Figure 18, the holes 41 of bolt through which the bolts 4 shown in Figures 1 and 2 pass holes 43 and pin through which passes the pin 6 to hold rotatively the support member 5, are formed in the side walls of the guide member 3. Also, oblong holes 42 are formed so that the pin 7 shown in Figures 1 and 2 can move. Figure 14 shows an assembled state. The guide member 3 is placed inside the head member 1. The guide flaps 12 of the slide 10 are adjusted between the guide positions 301 and the front faces 101 of the head member 1. The guide projections 301 fit into the guide slots 11. In addition, the guide surfaces 36 are in sliding contact with the inner walls of the guide member 3 so that the slide 10 can move up and down in the vertical direction. Also, the proximal end of the arm 8 is held by the supporting member 5 by the pin 7. Both ends of the pin 7 are placed inside the holes 42 formed in the elongate member 3 so that the guide pin 7 can move from in accordance with the rotation of the support member 5.

The operation of the modalities described above will now be described. The operation of the replacement of the cylindrical blades 14 will first be described. Under the condition that the cylindrical blade 14 is inserted into the through holes 25 and 26 of the blade holder 28 as shown in Figure 7, the blade holder 28 moves in the direction indicated by arrow A and is placed under the slide. 10 so that the head portion of the cylindrical blade 14 which projects from the blade holder 28 can be retained by the slider 10. By retaining the head portion of the cylindrical blade 14 in the slider 10 previously described, the slot 20 recessed in the head portion of the cylindrical blade 14 and is provided as in Figure 1, and the convex surface 21 engaging the recessed slot 20 is formed in the retention portion of the slider 10, as shown in Figures 11 and 13. As a result, the blade holder 28 simply moves in the direction indicated by the arrow A as shown in Figure 7A, while the arm 8 is lowered to lower the slide 10. and coupling the convex surface 21 with the recess 20, so that the head portion of the cylindrical blade 14 can be retained in the slider 10.

Also, the portion corresponding to the recessed slot 20 described above can be formed in a flanged portion having the convex surface and the portion corresponding to the concave portion 21 described above can be formed into a portion having the convex surface. Only by moving the knife holder 28 in the direction indicated by the arrow A while coupling the convex and concave portion, one with respect to the other, as shown in FIG. 7A, it will be possible to retain the head portion of the knife 14. cylindrical in the slide 10 in the same way. Also, the insertion hole 32 is provided in the retention portion of the cylindrical blade 14 of the slider 10, as shown in Figure 15. The arm 8 is raised to lift the slider 10 so that the cylindrical blade 14 Insert through the through holes 25 and 26 of the knife holder 28. Under this condition, the knife holder 28 moves in the direction indicated by the arrow in Figure 7A so that the knife holder 28 is placed under the slide 10. Then, the arm 8 is lowered to lower the slide 10 so that the head portion of the cylindrical blade 14 projecting from the blade holder 28 can fit within the insertion hole 32. Then, the screw 31 is bolted to the screw hole 33 so that the tip end of the screw 31 is engaged with the recessed slot 20 formed in the head portion of the cylindrical blade 14. As a result it is possible to retain the head portion of the cylindrical blade 14 in the slider 10. When inserting the head portion into the insertion hole 32, moving the blade holder 28 in the direction indicated by arrow A in Figure 7A, while that the arm 8 is lowered with low power and the head portion of the cylindrical blade 14 projecting from the head holder 18 in sliding engagement with the lower surface of the slide 10 is placed, it is possible to easily insert the head portion of the cylindrical blade 13 inside the insertion hole 32 without observing the operation. Also, the ribs 29 are formed in the holder 28 and the positioning surfaces 241 are formed in the vertical portions 24. The knife holder 28 is inserted until the positioning surfaces 241 come into contact with the lower portion 102 of the "U" recessed portion of the head member 1, under the guidance of the ribs 29. As a result it is possible to make coinciding the axis of the cylindrical blade 14 which is inserted through the through holes 25 and 26 of the blade holder 28, with the axis of the insertion hole 32. Under this condition, without any further operation, it is possible to easily insert the head portion of the cylindrical blade 14 into the insertion hole 32 without observing the insertion hole 32. The order of the replacement of the cylindrical blades 14 will now be described. First, the recessed slot 20 formed in the head portion of the cylindrical blade 14 is removed with a convex surface 21 formed in the slider 10. The case where the cylindrical blade 14 is retained in the slider 10 will be explained. Figure 7A, the paper loading surface 15 moves in the direction indicated by the arrow B. The attachment of the knife holder 28 by the recess portion 151 (see Figure 19) is released. The knife holder 28 is attracted in the direction opposite to the direction A. Then, a new cylindrical blade 14 is inserted into the through holes 25 and 26 of the knife holder 28. The arm 8 is lowered to the lowest position. As a result, the heights of the recessed groove 20 and convex surface 21 are identified with each other. If the knife holder 28 moves in the direction A. as shown in FIG. 7B, the recessed slot 20 and the convex surface 21 are adjusted with respect to each other. The knife holder 28 is placed in the position under the slide, and the cylindrical knife 14 is retained in the slide 10. Then, the paper loading surface 15 moves in a direction indicated by the arrow C so that the knife holder 28 is fixed by means of the recess portion 151 as shown in Figure 7C. In the embodiment shown in Figure 2, in the case where the head portion of the cylindrical blade 14 is inserted into the insertion hole 32, and the tip end of the screw 31 fits into the slot 20 wound so that the cylindrical blade 14 is retained in the slide 10, the order of replacement of the cylindrical blades 14 will now be described. First, the screw 31 loosens until the tip end of the screw 31 dgages from the recess 20. Then, the arm 8 is ra to a position where the lower end of the slide 10 does not interfere with the head portion of the cylindrical blade 14. As a result, since the coupling between the insertion hole 32 and the head portion of the cylindrical blade 14 includes displacement, the cylindrical blade 14 is not lifted by the slider 10. only the slider 10 is ra under the condition that the cylindrical blade 14 is left in the holder 28.

Subsequently, as shown in Figure 7a, the paper loading surface 15 moves in the direction B, and the attachment of the knife holder 28 by the recess portion 151 is released. The knife holder 28 is attracted in the opposite direction in the direction A. When the knife holder 28 is attracted, since it is possible to increase a space to any desired length between the lower end of the slide 10 and the head portion of the cylindrical blade 14 , the cut chips do not clog the space and the knife holder 28 can be attracted uniformly. Next, a new cylindrical blade 14 is inserted into the through holes 25 and 26 of the blade holder 28. The blade holder 28 is inserted in the direction A in FIG. 7A. The head portion of the cylindrical blade 14 is inserted into the insertion hole 32. The tip end of the screw 31 is coupled with the recess 20. Then, the paper loading surface 15 moves in the C direction as shown in Figure 7B. The knife holder 28 is fixed by the recess portion 151, as shown in Figure 7C. The guide of the cylindrical blade 14 by means of the blade holder 28 will now be described. In Figure 8, arm 8 moves up and down between positions 8A, 8B and 8C. The slide 10 moves up and down in the vertical direction between the position 10A, 10B and 10C, under the guidance of the guide flanges 12, the guide grooves 11 and the guide surfaces 36. By up and down movement of the slide 10, the cylindrical blade 14 retained in the lower end portion of the slide 10, also moves up and down between the positions 14A, 14B and 14C. Then, the upward and downward movement of the cylindrical blade 14 is guided by the through hole 25 of the blade holder 28. Accordingly, even when there is a slight displacement in the guide portions of the guide flanges 12, the slots 11 of guide and the guide surfaces 36 between the recessed slot 20 and the convex surface 21, the cylindrical blade 14 is guided by the through hole 25 and moves up and down in the vertical direction. Also, by increasing the height H2 of the through hole 25 (Figure 4), it is possible to more positively restrict the escape of the tip end of the cylindrical blade 14 during the piercing operation. With respect to the guide of the cylindrical blade 14 through the through hole 25, it is possible to enjoy the same effect in the case where the head portion of the cylindrical blade 14 is inserted into the insertion hole 32, as shown in FIG. Figure 2 In this way, even when there is a slight displacement in the coupling between the recessed slot 20 and the convex surface 21 (the coupling between the insertion hole 32 and the head portion of the cylindrical blade 14) and the guide portions of the guide tabs 12, guide grooves 11 and guide surfaces 36, the cylindrical blade 14 is guided by through holes 25. Since there is no upward and downward displacement of the tip end of the cylindrical blade 14, it is possible to form the lower blade 27 in the lower horizontal portion 23 of the blade holder 28, as shown in Figure 4 and to carry out the coupling high precision of the tip end of the cylindrical blade 14 and the lower blade 27, to cut and puncture the paper. As described in detail above, in accordance with a first aspect of the invention that will be understood from the detailed description thereof, by simple steps wherein the space defined by the horizontal to upper portion, the lower horizontal portion and the vertical portion to form the "U" shaped side elevation for the insertion of the paper is traversed by the cylindrical blade and the blade holder has the through holes formed in the upper horizontal portion and the lower horizontal portion through which the blade passes through. Cylindrical blade that is inserted and is attracted below the slide, it is possible to replace the cylindrical blades. Accordingly, the replacement of the cylindrical blades can be facilitated. Therefore, it is possible to improve the management property of the office instrument. Also, the head portion of the blade projecting towards the upper horizontal portion of the blade holder is retained in the slider and the upward and downward movement of the cylindrical blade is guided by the through hole formed in the upper horizontal portion of the blade. blade holder, regardless of the guide portions of the slide. Consequently, high-precision machining of the guide portions of the slide is dispensed with to reduce manufacturing cost. Then, the oscillation of the cylindrical blade is prevented and the drop position of the blade tip is determined exactly. It is possible to cut the paper between the tip end of the cylindrical blade and the lower blade and dispense with the pad. The handling property is improved as the office instrument dispensing with the replenishment of the pad. Also, it is possible to maintain a prolonged service life of the blades. It is possible to improve the function as an office instrument. According to a second aspect of the invention which is comprised of the detailed description thereof, the length of the through hole formed in the upper horizontal portion of the blade holder is lengthened to be greater than the length of the diameter of the through hole, the guide for the up and down movement of the cylindrical blade is more positive, the oscillating movement of the cylindrical blade is more effectively removed to keep the position of the tip end of the blade constant, the lower blade is provided in the through hole formed in the lower horizontal portion, and the tip end of the cylindrical blade is lowered to an exact position and inserted into the lower blade with high precision to cut and puncture the paper between the lower blade and the tip end of the blade cylindrical Accordingly, it is possible to dispense with the pad to improve the handling property as an office tool and to maintain a prolonged service life of the blades in order to improve the function of the office instrument. According to the third aspect of the invention which will be understood from the detailed description thereof, since the prevention of the oscillatory movement of the cylindrical blade does not depend on the guide portions of the slide, simply forming the recessed slot in the circumferential surface of the head portion of the cylindrical blade, which forms the convex surface to be coupled with the recessed slot in the retention portion of the slide for the cylindrical blade, inserting and attracting the blade holder below the slide in coupling between the recessed groove and the convex surface, it is possible to retain the head portion of the cylindrical blade in the slide. Accordingly, the replacement of the cylindrical blades is extremely simplified to improve the handling property as an office instrument. According to a fourth aspect of the invention that will be understood from the detailed description thereof, since the prevention of the oscillatory movement of the cylindrical blade does not depend on the guide portions of the slide, simply forming the flanged projection on the surface circumferentially of the head portion of the cylindrical blade, forming the concave surface, i.e., to be coupled with the flanged projection on the retention portion of the slide for the cylindrical blade, inserting and attracting the blade holder below the slide in coupling between the recessed groove and the convex surface, it is possible to retain the head portion of the cylindrical blade in the slide. Therefore, the replacement of the cylindrical blades is extremely simplified to improve the handling property as an office instrument. According to a fifth aspect of the invention which will be understood from the detailed description thereof, the insertion hole into which the head portion of the cylindrical blade is provided in the retention portion of the slide for the cylindrical blade, a screw hole with which the tip end of the screw engages is provided in the recessed slot formed in the head portion of the cylindrical blade which is inserted into the insertion hole, the holder having the through hole in which it is inserted. insert the cylindrical blade that is placed under the slide, the head portion of the cylindrical blade is inserted into the insertion hole by lowering the arm, the tip end of the screw fits into the recessed slot of the head portion and the head portion of the cylindrical blade is retained in the slide. It is possible to insert the head portion of the cylindrical blade into the insertion hole without observing the insertion hole in order to thereby extremely simplify the replacement of the cylindrical blades in order to improve the function as an office instrument.

Claims (5)

R E I V I N D I C A C I O N E S;

1. A punch in which a head portion of a blade is detachably detached towards a slide that moves up and down in a vertical direction, characterized in that a blade holder having a space for inserting paper, the space is in the form of "U" in lateral elevation defined by an upper horizontal portion, a lower horizontal portion and a vertical portion, through holes are formed in the upper horizontal portion and the lower horizontal portion so that the cylindrical blade passes through the space, the blade holder in the which cylindrical blade has been inserted into the through holes is inserted and is attracted below the slide, and a head portion of the blade projecting into the upper horizontal portion is retained by the slide.

The drilling machine according to claim 1, wherein a length of the through hole formed in the upper horizontal portion of the blade holder is greater than a length of the diameter of the through hole and a lower blade is formed in the through hole formed in the portion lower horizontal.

3. The drilling machine according to claim 1 or 2, wherein a recessed groove is formed in a circumferential surface of the head portion of the cylindrical blade, and a convex surface coupled with the recessed groove is formed in a retention portion of the sliding for the cylindrical blade. The drilling machine according to claim 1 or 2, wherein a convex flange portion is formed on a circumferential surface of the head portion of the cylindrical blade, and a concave surface coupled with the convex flange portion is formed in a portion of retention of the slide for the cylindrical blade. The drilling machine according to claim 1 or 2, wherein a recessed groove is formed in a circumferential portion of the cylindrical blade, an insertion hole within which a portion of the cylindrical blade is provided in the retention portion of the cylindrical blade. the slider for the cylindrical blade, and a screw hole is provided so that the tip end of a screw is engaged with the recessed slot of the inserted head portion within the insertion hole.