FI92957C - Procedure for manufacturing a drill bit - Google Patents

Description

92957

Method for making a drill bit

The invention relates to a method of manufacturing a drill bit comprising a body such as a metal tube, a rod of material or the like, the first end of which has fastening means for forcefully attaching the blade to an attachment point in the drill, such as a seat, mating surface or the like, and a substantially planar blade portion - a blade part made of a blank, such as a sheet metal, with two surface members, wherein a blade piece with a cutting edge is placed in connection with both surface members, the blade part blanks 20 connecting members to a center of rotation substantially in the base plane of the blade member such that the drill blade has a longitudinal direction of the body perpendicular to the base plane of the blade member blank; insert the blade pieces into the surface members.

25

The blade according to the invention is particularly suitable for use in an ice drill, in connection with which very many types of blades are currently used. U.S. Pat. No. 3,760,890 discloses a very general blade construction. The blade disclosed in the publication comprises a body part which is fastened at its first end, e.g. by a screw connection or correspondingly to the hollow body of the drill. The body part is attached at one end to a blade part with two curved cutting edges. 35 The blade part is fixed by welding to the body part so that the basic plane of the blade part, i.e. the plane of the plate blank from which the cutting edges are bent, substantially coincides with the longitudinal direction of the body part.

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A construction of the type shown is not preferable because, due to the method of manufacture, a continuous face is formed in the center of the blade. In order to obtain the correct shape 5 of the cutting edges, they need to be bent over a long area, which is why the manufacture of the blade requires great precision. Due to the long and steep bends, the arcuate surfaces formed on the blade also contribute to the unfavorable end faces. In this case, it is not possible to maintain the optimal position of the cutting edges relative to each other within the cutting edges 10. For this reason, after a few sharpenings, the drilling power of the blade is significantly reduced. In order to increase the service life of this type of blade, it is possible to use 15 loose blade pieces with certain reservations, but this does not eliminate the unfavorable end faces due to the way the blade part is made, which substantially reduces the maximum drilling power achievable with the blade.

U.S. Pat. No. 242,012 discloses a blade construction different from that described above, which consists of a body part and a blade part, respectively. In this solution, the body part comprises an angle-bent rod which is eccentrically welded at one end to the blade part 25 and whose first end coincides with the axis of rotation of the blade. The blade part is made of a substantially circular blade part blank, in which one cutting edge blank is formed by removing the central part and the part of the edge part of the blade part blank. The cutting edge of the cut-30 is then formed by bending the cutting edge blanks in a direction deviating from the basic plane of the blade part blank into a helical construction.

The solution presented in this publication has been able to reduce the end faces 35 acting against the drilling event.

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However, due to the asymmetrical attachment of the body part and the blade part, it is not possible to advantageously provide more than one cutting edge in connection with such a blade. Thus, the drilling power of such a blade naturally does not correspond to a blade with two cutting edges. In addition, the angled body portion, as well as its attachment point in the blade portion, are under high stress, which is why the body portion and the blade portion should be dimensioned relatively massively to provide sufficient rigidity. Em. for this reason, it is also not advantageous to use loose blade pieces, in which case the blade part as a whole has to be made of the material of the cutting edge, which in turn increases the manufacturing cost of the blade.

Finnish patent publication 20570 comprises an ice drill formed mainly by a circular steel plate disc. The disc is made of steel plate and is made approximately circular in shape and split in the middle, with one edge forming a blade. Since there is only one cutting edge, the drilling performance of such a blade remains inferior to that of a drill with two cutting edges. In addition, the blade is not provided with the possibility of using loose blade pieces, so that when the blade becomes bored, the entire blade part must be replaced with a new one.

Finnish patent publication 30284 comprises an ice drill with a round steel plate attached to the lower end of the shaft, in which blades are formed by bending cuts and cutting parts. Some of the blades are on the edges of the plate and some are inside the plate. Complicated tools are required to make the blade holes, which increases the manufacturing cost of the blade. In addition, the drill shank 35 is fork-shaped in construction, making it also more expensive to manufacture than a shank formed of a straight tube.

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If the drill bits become dull, the entire drill bit must be replaced, as it is not possible to use detachable blades.

The object of the method according to the present invention is to provide a decisive improvement over the above-mentioned drawbacks and thus to substantially increase the state of the art in the art. To achieve this purpose, the method according to the invention is mainly characterized in that triangular pieces are removed from the opposite edges of the blade part blank before bending in order to obtain surface member blanks.

The main advantages of the method according to the invention are the simplicity and accuracy of manufacture, since the blade-forming body and the blade part are attached to each other simply by fitting one end of the body to the center of the blade part and then to the blade part by welding. The method makes it possible to manufacture the blade in such a way that the ideal mutual position of the cutting edges can be maintained for a long time both when using loose blade pieces and by forming the cutting edges directly on the protruding surface members of the blade part 25.

In the following description, the invention will be illustrated in detail with reference to the accompanying drawings, in which Figure 1 shows a side view of a preferred V drill bit according to the invention, Figure 2 shows a perspective view of a 35 preferred steel according to the invention, and • ♦

II

5 92957 Figure 3 shows an end view seen from the cutting edge end of the blade.

The drill bit shown in preferred embodiments in Figures 1-3 comprises a body 1, such as a metal tube, a rod of material or the like, and a blade part 2 having at least one projecting surface member 2a, 2b in connection with which at least a cutting edge s can be arranged. 1a for transmitting the blade to a force-transmitting point in the drill, such as a seat, abutment or the like, the body 1 being force-connected at one end to the blade part 2. The blade part 2 15 is made of a substantially planar, circular-shaped blade part blank, such as a metal plate or plate. Protruding surface members 2a, 2b are formed from the surface member blanks preformed into the blade part blank by bending them in a direction different from the basic plane t of the blade part blank 20. The blade comprises a body 1 continuous in one longitudinal direction x, such as a straight metal tube, a rod of material or the like, connected at its other end by connecting members 3, such as a mating surface arrangement or the like fixedly, such as by welding or substantially to the center of rotation of the blade part 2, the blade 1, 2, 3 the longitudinal direction x of the body 1 perpendicular to the reference plane t.

In the embodiments shown in Figures 1-3, the mating surface arrangements of the connecting members 3 are formed by a shaft-sleeve arrangement, the other end of the body 1 acting as a shaft part being fixedly connected to the sleeve part 3a in the blade part 2 by two welded joints 3b on each side of the sleeve part 3a. The sleeve part 3a is formed by molding the blade part blank against the base plane t in a perpendicular direction.

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Further, according to Figs. 2 and 3, the body 1 is formed of a tube, the body 1 and the blade part 2 having a longitudinal x open in the center w of the blade 1, 2, 3 connected by the connecting members 3 and open to the opposite sides 5 of the blade. In this case, the proportion of the straight end face in the steel that hinders drilling is minimized.

A further preferred embodiment in the embodiment according to Fig. 1 is a guide member 5 10 arranged in the blade for guiding the drilled material, in particular from the steel in the ice drill 6. In this case, when viewed in the transverse direction, the helical guide plate 5, which partly fits into the circular shape of the blade part 2 and protrudes longitudinally from the base plane t to the body 1, is fixed by welding at one end to the rear surface of the surface member 2a 6 ends on the rear surface of the surface member 2a as a supporting structure.

20

The method according to the invention, e.g. for manufacturing steel applications of the type described above, is thus based on connecting a straight body 1 at one end with connecting members 25 3 to the center of rotation w of the blade part 2, the manufactured blade 1, 2, 3 having a body longitudinal direction x perpendicular to the base plane t . In this way, at its simplest, an ideal substantially rotationally symmetrical blade is obtained.

30

Furthermore, when the method is preferably applied, in the pre-preparation step of the blade, the connecting members 3 are first formed in the center of rotation w of the blade part blank. Thereafter, two substantially opposite surface member blanks 35 are made by removing the triangular pieces from opposite edge portions of the blade section blank. Thereafter, in the bending step, the surface members 2a, 2b of the blade part 2 • t are formed by bending the surface member blanks il 92927 into their final shape, after which in the finishing step the body 1 is fixedly connected at one end to the blade part 2 by a mating surface arrangement 3.

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In a further preferred embodiment, the connecting members 3 are formed by means of a pin-hole, shaft-sleeve arrangement or the like, the second end of the body 1, which is preferably tubular, with a welded joint 3b on each side of the second part 3a of the arrangement.

As a further preferred embodiment, the sleeve-like second part 3a of the abutment surface arrangement fixed in the blade part 2 is formed from the blade part blank. In this case, in the pre-preparation step 20, a hole is drilled in the rotary center w of the blade part blank, from which a sleeve part 3a is formed in the direction perpendicular to the base plane t by shaping, shaping or the like.

Furthermore, when using detachable blade pieces in connection with the blade, holes are preferably made in the surface members 2a, 2b in the blade preparation step for the fastening arrangement 4a of the separate blade piece 4, preferably for the rivet connection.

30

When manufacturing the blade according to Fig. 1 with a guide member 5 for guiding the drilled material, in particular from the steel in the ice drill 6, a helical guide plate 5 is preferably fitted to the blade 1, 2, 3 in the finishing step. Attached by welding at one end to the rear surface 2a and from one side to the body 1.

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It is clear that the invention is not limited to the applications presented above, but can be considerably modified within the framework of the basic idea. Naturally, the blade can be manufactured in such a way that the cutting edges 5 are formed directly on the surface members, in which case no separate blade pieces are required, because the blade according to the invention has considerably more sharpening space than the blades currently in use. Of course, the blade may comprise only one cutting edge, in which case, however, the ideal symmetry or drilling power for the cutting operation is not achieved. There may be more than two cutting edges, but in this case the effect of increasing the cutting efficiency may be questionable. Accordingly, the manufacturing method described above is advantageous because, by carrying out the work steps in the order shown therein, the desired blade shapes are ideally formed so as to avoid fractures caused during machining. Of course, by using suitable materials, a wide variety of manufacturing techniques, such as cold working or the like, can be applied. The method of the type described above is particularly suitable for heat treatment. Of course, it is also possible to use the blade for purposes other than the ice drilling described above.

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Claims (2)

A method of manufacturing a drill bit, the blade comprising a body (1) having fastening members (1a) at the first end for force-attaching the blade to a point of attachment in the drill, and at the other end a substantially planar blade part-blank 10 such as a sheet metal blade part ( 2) with two surface members (2a, 2b), wherein a blade piece (4) with a cutting edge (S) is placed in connection with both surface members (2a, 2b), whereby during the manufacture of the blade, 15. the surface member blanks of the blade part blank are bent substantially from the base plane ( t) to provide aberrant surface members (2a, 2b) and their end faces, and to connect the body (1) at one end fixedly with connecting members (3) to a center of rotation (w) substantially in the base plane (t) of the blade part (2) so that the drill bit (1) 2, 3) is the longitudinal direction (x) of the body (1) perpendicular to the base plane (t) of the blade part blank against, and 25. attaching the blade pieces (4) to the surface members (2a, 2b), characterized in that triangular pieces are removed from the opposite edges of the blade part blank before bending to obtain the surface member blanks. 30 10 92957 1. For the purposes of the application of the Community rules (1), in which case 5 of the provisions of this Regulation (1), for the purposes of the application of the Community rules (1), the finns en skärdel (2) tillverkad 10 av ett väsentligen planformigt skärdelämne, säsom en metalplät, som skärdelen (2) har tvä ytorgan (2a, 2b), varvid i samband med bäda ytorgan (2a, 2b) är placerad en med en skäregg (S) a cross-section, the colors of which are connected to the ground plane (s) for the ground plan (s) of the ground plane (2a, 2b) and the ground panel (2) with 20 means of disengagement (3) of the clearing element (2) of the point (w) of the end of the ground plan (s) of the drift (1, 2, 3) and of the stem (1, 2, 3) of the crossing (1) of the headings (x) grundplan (t), och 25 - fästas skärdelarna (4) account on the other side (2a, 2b), kännetecknad därav, att före bockningen avlägsnas triangulära bitar frän skärdelämnets motsatta kanter för att ästadkomma ytorganämnena. ti • «