HK1130729B - Shank attaching device - Google Patents

Description

Handle fixing device

Technical Field

The present invention relates to a shank fastening device for detachably fastening a drill including a core drill (core drill) to a rotating portion of a drill device, and capable of transmitting a relatively large torque of the drill device to the drill.

Background

As an example of a conventional shank attaching device, there is a device shown in fig. 9 (patent document 1). The shank holder 61 shown in the drawing is a device for fixing a core drill 62 to a rotating part of a drill unit (not shown), and includes a spindle 63 and a shank 64. The fixed shaft 63a formed on the spindle 63 is detachably attached to the rotating portion of the drill unit, the spindle 63 and the shank 64 are detachably attached to each other, and the shank 64 and the core drill 62 are joined together. The shank 64 is fixed to the spindle 63, and an engagement steel ball 65 provided on the spindle 63 is engaged with an engagement recess 66 formed in the shank 64. By the engagement of the engagement steel ball 65 and the engagement recess 66, the axial movement of the shank 64 out of the spindle 63 can be prevented, and the torque of the spindle 63 can be transmitted to the shank 64 and the core drill 62.

In the conventional shank attachment device 61 shown in fig. 9, a center bit attachment hole is formed in the spindle 63, and the base end portion of the center bit 67 is inserted into the center bit attachment hole. The base end portion of the center drill 67 is fixed to the spindle 63 by a fixing screw 68, and the fixing screw 68 is screwed into a fixing screw hole formed in the spindle 63.

Patent document 1: japanese patent application laid-open No. 2002-192412.

Disclosure of Invention

However, in the conventional shank fixing device 61 shown in fig. 9, if it is desired to design a shank fixing device 61 that can sufficiently withstand a torque acting on, for example, such an engagement steel ball 65 and an engagement concave portion 66, the volume of the shank fixing device 61 may increase, and the boring work efficiency may decrease. This is because the engagement between the engagement steel ball 65 and the engagement recess 66 has a function of transmitting the torque of the spindle 63 to the shank 64 and the hollow drill 62 and a function of preventing the shank 64 from moving in the direction away from the spindle 63, and therefore, when it is desired to transmit a large torque, it is necessary to have a structure capable of combining the axial coupling force of the shank 64 and the spindle 63, and the space for selecting a structure for downsizing is reduced.

As shown in fig. 9, when the core drill 62 and the center drill 67 are fixed to each other and the shank fixing device 61 is used, there is a possibility that the fixing screw 68 for fixing the center drill 67 to the mandrel 63 may be loosened and detached due to vibration during the boring operation.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a shank attachment device that can transmit a relatively large torque and can be made relatively small.

The shank fixing device of the present invention is a device for fixing a drill to a rotating portion of a drill device, and includes a spindle detachably attached to the rotating portion, and a shank detachably attached to each other, wherein an engaging member provided on the spindle engages with an engaging groove formed on a side surface of the shank in a state where the shank is fixed to the spindle, thereby preventing the shank from moving in an axial direction away from the spindle, and a 1 st engaging portion provided on the spindle engages with a 1 st engaged portion provided on the shank, thereby transmitting torque of the spindle to the shank, and the shank comes into contact with the spindle, thereby preventing the shank from moving in an axial direction in which the spindle approaches.

When the piercing operation is performed using the shank fixing device of the present invention, for example, the shank is first fixed to the mandrel, and then the drill is fixed to the shank. Then, the mandrel to which the shank and the drill bit are fixed is fixed to the rotating portion of the drill bit device. The drill bit assembly may then be actuated to drill a hole in the workpiece with the drill bit. Further, since the engagement member provided on the spindle is engaged with the engagement groove formed in the shank in a state where the shank is fixed to the spindle, the shank can be prevented from moving in the axial direction away from the spindle, and the shank cannot be removed from the spindle. In this state, the 1 st engaging portion provided on the spindle is engaged with the 1 st engaged portion provided on the shank, so that the torque of the spindle can be transmitted to the shank. In this state, the shank is in contact with the mandrel, and the shank is prevented from moving in the axial direction toward the mandrel, so that the mandrel can receive an axial impact generated during the punching operation through the contacted portion. Therefore, the punching operation can be performed efficiently. Further, since the drill can be detachably fixed to the shank, if the drill as a consumable part is worn, the shank can be used by simply replacing the drill.

In the shank fixing device according to the present invention, the 2 nd engaging portion provided in the shank may be engaged with the 2 nd engaged portion provided in the drill in a state where the drill is fixed to the shank, so that the torque of the shank can be transmitted to the drill. By doing so, a relatively large torque of the shank can be transmitted to the drill such as a core drill through the 2 nd engaging portion and the 2 nd engaged portion which are engaged with each other, and a hole having a relatively large diameter can be drilled.

In the shank fixing device of the present invention, the 1 st engaging part may be a concave part or a convex part, the 1 st engaged part may be a convex part or a concave part, the 2 nd engaging part may be a concave part or a convex part, and the 2 nd engaged part may be a convex part or a concave part. With this configuration, a relatively large torque of the spindle can be transmitted to the shank with a relatively simple configuration, and a relatively large torque of the shank can be transmitted to the drill.

In the shank fixing device of the present invention, the 1 st engagement receiving portion and the 2 nd engagement receiving portion may be formed in a torque transmission annular member, and the torque transmission annular member and the drill may be fixed to the shank with screws in a state where both are engaged with each other. In this way, when the 1 st engaged portion and the 2 nd engaged portion are formed in the torque transmission annular member, a relatively large torque can be transmitted by increasing the diameter of the torque transmission annular member and increasing the distances from the rotation center of the 1 st engaging portion, the 1 st engaged portion, the 2 nd engaging portion, and the 2 nd engaged portion. Further, since the torque transmission annular member can be manufactured separately from the spindle and the shank, the torque transmission annular member can be manufactured relatively easily as compared with a case where the spindle and the shank are integrally manufactured.

The shank attaching device of the present invention may be configured such that the mandrel has a fixed shaft fixed to a rotating portion of the drill device, a diameter-enlarged portion is provided at a distal end portion of the fixed shaft, the diameter-enlarged portion is detachably screwed to a base of the mandrel by a screw, the shank is detachably attached to a shank attaching hole formed in the mandrel, a central drill attaching hole communicating with the shank attaching hole is provided in the base of the mandrel, a fixing screw hole having a female screw formed on an inner peripheral surface thereof is provided from an outer peripheral surface of the base toward a center of the central drill attaching hole so as to be perpendicular to the central drill attaching hole, a fixing screw is screwed into the fixing screw hole, a distal end of the fixing screw is allowed to protrude into the central drill attaching hole, and at least a part of the fixing screw screwed into the fixing screw hole is covered with the diameter-enlarged portion from an outer side, thereby preventing the fixing screw from falling off to the outside of the substrate.

In this way, the spindle can be divided into the fixed shaft side portion and the base side portion in a detachable manner, and thus, when the fixed shaft is damaged, the damaged fixed shaft side portion can be replaced with another fixed shaft side portion, and there is no need to replace the base side portion, which is economical. And the center bit may be fixed to the base body of the spindle with a fixing screw in a state of being inserted into the center bit fixing hole. The fixing screw may be loosened by vibration when the drill and the center drill are used for drilling, but since the diameter-enlarged portion of the mandrel covers at least a part of the fixing screw screwed into the fixing screw hole from the outside, the fixing screw can be prevented from falling off the base body.

The stem fixing device according to the present invention is configured to detachably fix the stem to a stem fixing hole formed in the spindle, and includes a support member that restricts the engagement member from protruding into the stem fixing hole when the stem is not fixed to the stem fixing hole, the support member being formed by a tip end of a coil spring disposed in the stem fixing hole, a base end portion of the coil spring being engaged with an engagement groove portion, and the engagement groove portion being in contact with an inner peripheral surface of an inner portion of the stem fixing hole.

The support member for restricting the projection of the engaging member into the shank securing hole in this manner is formed by the tip end of the coil spring disposed in the shank securing hole, and the number of parts can be reduced in accordance with the reduction in the number of support members.

In order to design a shank attachment device of the present invention to sufficiently withstand the torque applied by the impact, the strength in the direction in which the torque is applied may be increased for the 1 st engaging part provided on the spindle and the 1 st engaged part provided on the shank. Therefore, the engagement strength between the engagement member for preventing the movement of the shank in the axial direction away from the mandrel and the engagement groove does not need to be increased, and therefore the shank fixing device can be made relatively small. Further, since the axial impact generated during the punching operation can be received by the portion where the shank and the mandrel are in contact, it is not necessary to consider the strength against the axial impact for the 1 st engaging portion, the 1 st engaged portion, the engaging member, and the engaging groove, and therefore the shank fixing device can be downsized.

Drawings

Fig. 1 is a partially sectional front view showing an exploded state (a state where a stem is removed from a mandrel) of a stem fixing device according to embodiment 1 of the present invention.

Fig. 2 is a partially sectional front view showing an assembled state (a state in which a shank is fixed to a mandrel) of the shank fixing device shown in fig. 1.

Fig. 3 is an enlarged front view, partially in section, showing an exploded state of a mandrel of the shank fixture shown in fig. 1.

FIG. 4 is an IV-IV view of FIG. 1 showing the 1 st engaging part of the shank attachment device shown in FIG. 1.

FIG. 5 is a view in the V-V direction of FIG. 1 showing the 1 st engaging part of the shank attachment device shown in FIG. 1.

Fig. 6 is a partially sectional front view showing an assembled state (a state in which a shank is fixed to a mandrel) of the shank fixing device according to embodiment 2 of the present invention.

Fig. 7(a) is a plan view showing the stem of fig. 6, and fig. 7(b) is a partial sectional front view showing an exploded state of the stem of fig. 6.

FIG. 8(a) is a partially sectional front view showing a state where a core drill is fixed to the shank of FIG. 6,

fig. 8(b) is a plan view of the core drill mounted on the shank of fig. 8 (a).

Fig. 9 is a partially sectional front view showing a conventional shank attachment device.

Description of the symbols

A. B handle fixing device

D drill bit device

Rotating part of D1 drill bit device

1 mandrel

2. 3 handle

4 handle body

11A fixed shaft

11B diameter expanding part

11a female screw hole

11b plane

11e engaging groove

12 base body

12A handle fixing hole

12D center drill fixing hole

12E fixing screw hole

12G the 1 st engaging part

12a recess

12b male screw part

12c engaging member receiving hole

12f engaging groove part

12p plane

13 operating sleeve

13a, 13c operating the expanded diameter portion of the sleeve

13b reduced diameter portion of operating sleeve

13d expanded diameter section of operating sleeve

14. 30 helical spring

15. 20 jaw-like part

16 brake ring

17 engaging member

20G the 1 st engaged part

20a convex part

21 insertion part

21A engaging groove

22 drill bit fixing part

25 male screw

Base end of 30a coil spring

30b coil spring front end portion

40 center drill bit

41 set screw

50. 51 hollow drill (drill)

50a female screw

51a core drill 2 nd engaged part

52 annular member for torque transmission

52a 2 nd engaging part

52c, 51b center hole

53 nut

54 drill bit fixing part

54a 1 st engagement circumferential surface

54b the 2 nd engaging peripheral surface

54c male screw part

60 drill bit (bit) fixing hole

Detailed Description

The stem fastening device according to embodiment 1 of the present invention will be described with reference to fig. 1 to 5. A shank attachment device a shown in fig. 1 and 2 is a device for attaching a core drill 50 to a rotating portion D1 of a drill device D such as an electric drill, and includes a spindle 1 and a shank 2.

As shown in fig. 1 to 3, the spindle 1 has a fixed shaft 11A having a hexagonal cross section at its base end. The fixed shaft 11A is provided with a small-diameter engaging groove 11e around its axis. As shown in fig. 1, the engagement groove 11e is a groove for preventing the handle fixing device a from coming off the rotating portion D1 when the handle fixing device a is fixed to the rotating portion D1. An enlarged diameter portion 11B is integrally formed on the distal end side of the fixed shaft 11A.

As shown in fig. 3, the enlarged diameter portion 11B has a bottomed female screw hole 11a opened at the front end, and a flat surface 11B for engaging a wrench or the like is formed on the outer peripheral surface of the enlarged diameter portion 11B. The flat surfaces 11B are formed at two positions 180 ° apart in the circumferential direction on the outer peripheral surface of the enlarged diameter portion 11B, for example.

As shown in fig. 3, the mandrel 1 includes a base 12 that is screwed to the enlarged diameter portion 11B, and has a structure in which a male screw portion 12B that is screwed to a female screw hole 11A of the enlarged diameter portion 11B is provided at a base end portion of the base 12, and the fixed shaft 11A that is joined to the enlarged diameter portion 11B can be fixed to the base 12 by screwing the male screw portion 12B to the female screw hole 11A. The fixed shaft 11A can be removed from the base 12 by releasing the screw-on state.

As shown in fig. 3, the base 12 is formed with a shank fixing hole 12A that opens toward the tip end side in a portion from the tip end portion to the center portion. Then, an engaging member accommodating hole 12c penetrating in the radial direction is formed in the base 12 at a portion slightly closer to the base end side from the tip end of the shank fixing hole 12A. As shown in fig. 3, an operation sleeve 13 is disposed at the distal end of the base 12 so as to cover the outer periphery thereof.

As shown in fig. 3, the operation sleeve 13 is formed in a substantially short cylindrical shape, and the outside of the engagement member accommodating hole 12c is slidably provided in the axial direction (vertical direction in fig. 3) of the spindle 1. As shown in the figure, a cam surface for projecting and retracting the engaging member 17 (e.g., a steel ball) into the shank fixing hole 12 is formed on the inner peripheral surface of the operating sleeve 13.

The cam surface includes a portion 13a in which the inner peripheral surface of the distal end portion of the operating sleeve 13 is slightly expanded in diameter and a portion 13b in which the diameter is slightly reduced on the base end side thereof, and the two portions 13a and 13b are formed with stepped portions having a rectangular cross section. A portion 13c having an inner peripheral surface with a larger diameter is formed on the base end side of the reduced diameter portion 13b of the operation sleeve 13. An expanded diameter portion 13d having an expanded diameter on both the outer peripheral surface and the inner peripheral surface is formed on the base end portion of the operation sleeve 13. A step is formed at the boundary between the diameter-enlarged portion 13d and the diameter-enlarged portion 13 c.

As shown in fig. 2, the coil spring 14 is fixed to the inside of the operation sleeve 13, and is acted on by the elastic force of the coil spring 14 toward the front end side (downward) of the base 12. However, the operation sleeve 13 is restricted from further moving toward the distal end side by the contact with the collar portion 15. Further, the operation sleeve 13 is in contact with the proximal end side stopper ring 16, and thereby the operation sleeve 13 is restricted from further moving toward the proximal end side.

Thus, the operation sleeve 13 can slide only a predetermined distance in the vertical direction of fig. 2. That is, as shown in fig. 2, in a state where the operation sleeve 13 is moved to the lowered position by the elastic force of the coil spring 14, the stopper member 17 can be pressed by the reduced diameter portion 13b to protrude into the shank fixing hole 12A.

As shown in fig. 3, when the handle 2 is removed from the spindle 1, that is, when the operating sleeve 13 is moved to the raised position against the elastic force of the coil spring 14, the diameter-enlarged portion 13a accommodates the engaging member 17, so that the engaging member 17 can be retracted from the inside of the handle fixing hole 12A into the engaging member accommodating hole 12c, and the engaging member 17 can be prevented from protruding into the handle fixing hole 12A.

In the present embodiment, the inside diameter of the engagement member housing hole 12c on the shank fixing hole 12A side is slightly reduced, and the engagement member 17 does not fall into the shank fixing hole 12A.

As shown in fig. 3, a coil spring 30 having an outer diameter slightly smaller than an inner diameter of the shank attachment hole is attached to the shank attachment hole 12A. The coil spring 30 has a pushing-out function of pushing out the stem 2 toward the distal end side and a function as a support member of restricting the movement (or falling-out) of the engagement member 17 protruding into the stem fixing hole 12A.

As shown in fig. 3, the coil spring 30 is formed such that the pitch of each turn of two base end portions 30a and three tip end portions (support members) 30b is substantially equal to the size of the wire of the coil spring 30. The proximal end portion 30a is engaged with an engagement groove portion 12f having an annular groove shape provided around the proximal end of the shank fixation hole 12A. The tip end portion (support member) 30b of the coil spring 30 is formed to extend so as not to insert the stem 2 into the stem fixing hole 12A, and extends to a position covering the opening portion of the engagement member housing hole 12c on the stem fixing hole 12A side from the inside, and in this state, the tip end portion 30b applies a force in the outward direction to the engagement member 17, and a state is formed in which the engagement member 17 does not protrude into the stem fixing hole 12A.

As shown in fig. 2, a center drill fixing hole 12D is formed in the base 12. The center bit fixing hole 12D has an inner diameter into which the center bit 40 can be inserted, and is provided at a position where the center bit 40 can be fixed to the rotation center of the base 12. The center bit fixing hole 12D communicates with the base end side of the fixing hole 12A, and has a diameter smaller than that of the shank fixing hole 12A.

As shown in fig. 2, a fixing screw hole 12E having a female screw on the inner peripheral surface is formed in the base 12 so as to be perpendicular to the center bit fixing hole 12D from the outer peripheral surface of the base 12 toward the center of the center bit fixing hole 12D. Then, a fixing screw 41 having a hexagonal wrench hole is screwed into the fixing screw hole 12E. That is, the proximal end portion of the center bit 40 can be fixed to the center bit fixing hole 12D by the fixing screw 41. The fixing screw 41 is configured such that the base end (outer end) of the fixing screw 41 is positioned near the outer opening edge of the fixing screw hole 12E in a state where the fixing screw is screwed into the fixing screw hole 12E and the center drill 40 is fixed, and in this state, at least a part of the base end of the fixing screw 41 is covered with the tip end of the female screw hole 11a of the enlarged diameter portion 11B. The fixing screw 41 is formed longer than the dimension between the inner diameter of the center bit fixing hole 12D and the inner diameter of the female screw hole 11a of the enlarged diameter portion 11B.

Further, a flat surface 12p for locking a wrench or the like is formed on the outer surface of the base 12. The flat surface 12p is formed in the vicinity of the enlarged diameter portion 11B screwed to the base 12. And the flat surface 12p is formed at two places on the outer peripheral surface with an interval of 180 °.

As shown in fig. 1, a 1 st engaging portion 12G is formed on the lower surface of the flange portion 15 of the base 12. The 1 st engaging portion 12G is capable of engaging with a 1 st engaged portion 20G formed on the upper surface of the flange portion 20 of the shank 2 in the rotational direction.

The shaft 2 will be explained below. As shown in fig. 1, the shank 2 has an insertion portion 21 formed at a proximal end portion and a bit fixing portion 22 formed at a distal end portion. The insertion portion 21 is a portion to be inserted into the shank fixing hole 12A, and the drill fixing portion 22 is a portion to which a drill (a hollow drill in the present embodiment) 50 is fixed.

The insertion portion 21 is formed in a substantially short cylindrical shape having a small diameter slightly smaller than the shank fixation hole 12A, as shown in fig. 1. An engaging groove 21A for engaging with the engaging member 17 of the spindle 1 is formed on the outer periphery of the insertion portion 21.

As shown in fig. 1, the drill fixing portion 22 is formed in a substantially short cylindrical shape, and a male screw 25 is formed on an outer peripheral surface thereof. The male screw 25 is screwed with a female screw 50a formed on the inner peripheral surface of the core drill 50. Accordingly, the hollow drill 50 can be fixed to the shank 2 by screwing the female screw 50a of the hollow drill 50 to the male screw 25 formed on the shank 2 side.

However, in the case of the shank attachment device a shown in fig. 1, the shank 2 capable of attaching the core drill 50 may be used, but the following alternative means may be used. In the case where the drill to be fixed is a drill other than the core drill 50, for example, a drill having a cylindrical outer shape such as the center drill 40 shown in fig. 1, which is cut by a cutting edge at the tip end and has a spiral chip discharge groove on the outer peripheral surface, a shank having a screw fixing structure such as the fixing screw 41 shown in fig. 1 provided at the drill fixing portion may be used instead of the shank 2 shown in fig. 1. Alternatively, a shank provided with a chucking mechanism using a chuck structure for chucking a drill on a rotary shaft, which is conventionally known, may be used.

As shown in fig. 1, a collar portion 20 is formed between the insertion portion 21 and the bit fixing portion 22, and the 1 st engagement receiving portion 20G is formed on the upper surface of the collar portion 20. The 1 st engaged portion 20G is formed to be engageable with the 1 st engaging portion 12G formed on the lower surface of the spindle 1. With this, the torque of the spindle 1 can be transmitted to the shank 2 through the 1 st engaging portion 12G and the 1 st engaged portion 20G that are engaged with each other.

As shown in fig. 5, the 1 st engaging part 20G has projections 20a formed at intervals of 120 ° in the circumferential direction 3. As shown in fig. 4, the 1 st engaging portion 12G has recesses 12a formed at 60 ° intervals in the circumferential direction 6 so as to be engageable with the projections 20a of the 1 st engaged portion 20G. Therefore, when the shank 2 is fixed to the mandrel 1, the convex portion 20a can be engaged with the concave portion 12a if the shank 2 is rotated by 60 ° in the circumferential direction, for example.

The following describes a procedure of performing a punching operation on a workpiece or the like using the shank fixing device a configured as described above, and the operation and effect of the shank fixing device a. First, as shown in fig. 1, for example, a hollow drill 50 is fixed to a shank 2. When the hollow drill 50 is fixed to the shank 2, the female screw 50a of the hollow drill 50 may be screwed and fixed to the male screw 25 of the shank 2.

Then, the shank 2 to which the core drill 50 is fixed to the mandrel 1 as shown in fig. 2. That is, the insertion portion 21 of the shank 2 is inserted into the shank fixing hole 12A of the spindle 1. During this insertion, when the tip end of the stem 2 is pushed up to the extent that the tip end portion 30b of the coil spring 30 is pushed into the stem fixing hole 12A and the engaging member 17 can move into the stem fixing hole 12A, the engaging member 17 comes into contact with the outer peripheral surface of the insertion portion 21 and the lower surface of the collar-like portion 15 comes into contact with the upper surface of the collar-like portion 20. Next, the shank 2 is rotated by an appropriate angle (at least 60 degrees or less) with respect to the spindle 1 as necessary, and the shank and the spindle are engaged with each other so that the concave portion 12a of the 1 st engaging portion 12G and the convex portion 20a of the 1 st engaged portion 20G are engaged with each other. When the insertion portion 21 of the shank 2 is further inserted into the shank fixing hole 12A from this state, the engagement member 17 is engaged with the detent groove 21A of the insertion portion 21, whereby the shank 2 can be fixed to the spindle 1 as shown in fig. 2.

As shown in fig. 2, when the handle 2 is fixed to the spindle 1, the operating sleeve 13, which is subjected to the spring force of the coil spring, moves downward, and the operating sleeve 13 comes into contact with the collar portion 15, the reduced diameter portion 13b presses the engaging member 17 against the detent groove 21A.

Then, after or before the shank 2 is fixed to the spindle 1, as shown in fig. 2, the base end portion of the center bit 40 is inserted into the center bit fixing hole 12D of the spindle 1 to be fixed. At this time, the fixing screw 41 is fastened to the fixing screw hole 12E, and the center drill 40 is fixed to the base body 12 of the spindle 1.

Next, as shown in fig. 1, the fixed shaft 11A of the spindle 1 is fixed to a bit (bit) fixing hole 60 of a drill device D such as an electric drill, and the drill device D is operated. With this, a desired hole can be drilled using the core drill 50 and the center drill 40.

As shown in fig. 2, in a state where the shank 2 is fixed to the spindle 1, the engagement member 17 provided in the spindle 1 is engaged with the detent groove 21A formed in the shank 2, so that the shank 2 can prevent the axial movement away from the spindle 1, and the shank 2 does not fall off from the spindle 1. In this state, the 1 st engaging portion 12G provided on the spindle 1 is engaged with the 1 st engaged portion 20G provided on the shank 2, so that a large torque or an impulsive torque from the spindle 1 can be transmitted to the shaft 2.

In this state, the jaw-like portion 20 of the shank 2 comes into contact with the jaw-like portion 15 of the spindle 1, and axial movement of the shank 2 toward the spindle 1 is reliably prevented, so that the spindle 1 can receive an axial impact generated during a punching operation through the jaw-like portions 15, 20. With this, the punching can be performed efficiently.

Further, since the core drill 50 is detachably fixed to the shank 2, if the core drill 50, which is a consumable part, is damaged, the shank 2 can be used as it is by simply replacing the core drill 50.

Instead of the core drill 50 shown in fig. 1, a core drill having a different outer diameter from that of the core drill may be fixed to the shank 2. That is, by configuring the female screw 50a of the core drill 50 to be screwed to the male screw 25 of the drill fixing portion 22, core drills having different sizes can be fixed to the shank 2.

In addition, if the shank fixing device a of the present embodiment is designed to be able to sufficiently withstand the torque applied by the impact, the strength in the torque application direction of the 1 st engaging portion 12G provided in the spindle 1 and the 1 st engaged portion 20G provided in the shank 2 may be designed to be sufficiently large. Accordingly, the strength of the engagement between the engaging member 17 and the engaging groove 21A for preventing the axial movement of the stem 2 protruding from the arbor 1 is not required to be large, and therefore the stem fixing device a can be made relatively small, and the 1 st engaging portion 12G, the 1 st engaged portion 20G, the engaging member 17, and the engaging groove 21A can receive the axial impact generated at the time of the punching operation because the flange portions 15 and 20, which are the contact portions of the stem 2 and the arbor 1, do not need to be considered to have the strength of receiving the axial impact, and therefore the stem fixing device a can be made compact.

As shown in fig. 3, the spindle 1 is divided into a part on the fixed shaft 11A side and a part on the base 12 side, and is detachably connected to the male screw part 12b and the female screw part 11A, so that when the fixed shaft 11A is damaged, the damaged part on the fixed shaft 11A side can be replaced with another part on the fixed shaft 11A side, and the part on the base 12 side is unnecessary, and therefore, it is economically preferable.

As shown in fig. 2, the center drill 40 can be fixed to the base 12 of the mandrel 1 by the fixing screw 41 in a state inserted into the center drill fixing hole 12D, but the fixing screw 41 may be loosened by vibration when drilling is performed using the core drill 50 and the center drill 40, but since the enlarged diameter portion 11B of the mandrel 1 covers at least a part of the fixing screw 41 screwed into the fixing screw hole 12E from the outside, the fixing screw 41 can be prevented from coming off the base 12.

As shown in fig. 1, the shank attachment device a includes a support member (distal end 30b) configured to limit the engagement member 17 from protruding into the shank attachment hole 12 when the shank 2 is not attached to the shank attachment hole 12A, and the support member is configured to be formed by the distal end 30b of the coil spring 30 disposed in the shank attachment hole 12A. The support member that regulates the projection of the engaging member 17 into the shank fixing hole 12A in this way is formed by the tip 30b of the coil spring 30 disposed in the shank fixing hole 12A, whereby the number of parts can be reduced in accordance with the reduction in the number of support members.

In the shank fixing device a shown in fig. 2, since the shank 2 can be removed from the mandrel 1 by moving the operation sleeve 13 upward in the axial direction, even if an inertial force in the rotational direction acts on the shank fixing device a in a state of being fixed to the drill bit device D and used, the engagement member 17 retreats from the shank fixing hole 12A due to the inertial force, and the shank 2 does not fall off from the mandrel 1.

When the handle 2 is removed from the mandrel 1, the worker may move the operation sleeve 13 toward the proximal end side (upward) from the state shown in fig. 2. With this, the engaging member 17 is moved outward, and the stem 2 is pushed out from the stem fixing hole 12A of the spindle 1 to the distal end side by the elastic force of the coil spring 30.

Next, a stem fastening device B according to embodiment 2 of the present invention will be described with reference to fig. 6 to 8. The shank attachment device B of embodiment 2 shown in fig. 6 differs from the shank attachment device a of embodiment 1 shown in fig. 2 in the structure in which the hollow drills 51, 50 are fixed to the shanks 2, 3. Otherwise, the same components as those of the shank attachment device a of embodiment 1 shown in fig. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the shank attachment device B according to embodiment 2, as shown in fig. 6, a core drill 51 having a relatively large outer diameter can be attached, and a hole having a relatively large diameter can be drilled using the core drill 51.

Fig. 7(a) is a plan view showing a state where the stem 3 is assembled, and fig. 7(b) is a partial sectional front view showing a state where the stem 3 is disassembled. As shown in fig. 7(b), the shank 3 includes a shank body 4, a torque transmission annular member 52, and a nut 53. The shank body 4 includes an insertion portion 21 and a bit fixing portion 54. However, the insertion portion 21 is similar to the insertion portion 21 of embodiment 1 shown in fig. 1, as shown in fig. 8 (a).

As shown in fig. 8(a), the bit fixing portion 54 is formed in a substantially short cylindrical shape, and includes a 1 st engaging circumferential surface 54a on the outer circumferential surface of which the torque transmission annular member 52 is fixed, a 2 nd engaging circumferential surface 54b on which the top plate of the core drill 51 is attached, and a male screw portion 54c to which the nut 53 is screwed. The outer diameter of the 1 st engagement circumferential surface 54a is maximized, the 2 nd engagement circumferential surface 54b is made smaller, and the male screw portion 54c is minimized.

As shown in fig. 7 and 8, the torque transmission ring member 52 has a substantially annular plate shape, and has a 1 st engaged portion 20G formed on an upper surface thereof and a 2 nd engaging portion 52a formed on a lower surface thereof. The 1 st engaging part 20G includes three convex parts 20a similar to those of the 1 st embodiment, and 6 concave parts 12a are formed on the lower surface of the flange-like part 15 of the spindle 1 shown in fig. 6 so that the three convex parts 20a can be engaged with each other. The 6 recesses 12a are the 1 st engaging portion 12G, and are the same members as those of embodiment 1.

The 2 nd engaging portion 52a is configured to be engageable with a 2 nd engaged portion 51a formed on the top plate of the hollow drill 51. With this, the torque of the shank 3 can be transmitted to the hollow drill 51 through the 2 nd engaging portion 52a and the 2 nd engaged portion 51a that are engaged with each other.

As shown in fig. 7(a) and (b), the 2 nd engaging portion 51a is a convex portion, and two portions are formed at an interval of 180 ° in the circumferential direction. As shown in fig. 8(a) and (b), the 2 nd engaging portion 51a is a recess (small hole) capable of engaging with the projection as the 2 nd engaging portion 52a, and is formed in two positions at 180 ° intervals in the circumferential direction.

When the torque transmission annular member 52 and the hollow drill 51 are fixed to the shank body 4 configured as described above, as shown in fig. 8(a), first, the respective center holes 52c and 51b of the torque transmission annular member 52 and the hollow drill 51 are sequentially attached to the drill fixing portion 54, the 2 nd engaging portion 52a of the torque transmission annular member 52 and the 2 nd engaged portion 51a of the hollow drill 51 are engaged with each other, and then, the nut 53 is screwed onto the male screw portion 54c of the shank 3 to fasten them. Then, as in embodiment 1, as shown in fig. 6, the shank 3 to which the core drill 51 is attached is fixed to the mandrel 1.

Then, as in embodiment 1, as shown in fig. 6, the base end portion of the center bit 40 is inserted into the center bit fixing hole 12D of the spindle 1, and the center bit 40 is fixed to the spindle 1 by the fixing screw 41.

Next, as shown in fig. 1, the fixed shaft 11A of the spindle 1 is fixed to, for example, a drill (bit) fixing hole 60 of the drill device D of the charging chamber, and then the drill device D is operated. With this, a desired hole can be drilled using the hollow drill 51 and the center drill 40.

In the case of the shank attachment device B having the above-described configuration, as shown in fig. 6, when the core drill 51 is attached to the shank 3 and the shank 3 is attached to the mandrel 1, the torque of the mandrel 1 can be transmitted to the core drill 51 through the torque transmission annular member 52. Further, since the 2 nd engaging portion 52a provided in the torque transmission annular member 52 is engaged with the 2 nd engaged portion 51a provided in the hollow drill 51, a relatively large torque of the shank 3 can be transmitted to the hollow drill 51, and a hole having a relatively large diameter can be drilled.

Further, as shown in fig. 1, 6, and 7, if the 1 st engaging portion 12G is a recess 12a (or a convex portion) and the 1 st engaged portion 20G is a convex portion 20a (or a concave portion), or if the 2 nd engaging portion 52a is a recess (or a convex portion) and the 2 nd engaged portion 51a is a convex portion (a concave portion), it is possible to transmit a relatively large torque of the spindle 1 to the shank 3 and a relatively large torque of the shank 3 to the hollow drill 51 with a relatively simple configuration.

As shown in fig. 6, since the first engaged portion 20G and the second engaged portion 52a are formed in the torque transmission annular member 52 and the hollow drill 51 are fastened to the shank 3 by the nut 53 in a state where they are engaged with each other, it is possible to increase the distance between the first engaged portion 12G, the first engaged portion 20G, the second engaged portion 52a, and the second engaged portion 51a and the rotation center while increasing the diameter of the torque transmission annular member 52, and to transmit a relatively large torque by such a configuration. Further, since the torque transmission annular member 52 can be manufactured separately from the spindle 1 and the shank 3, the manufacturing can be made relatively simple as compared with a case where the spindle 1 and the shank 3 are integrally manufactured. Otherwise, the operation is the same as that of embodiment 1, and therefore, the description thereof is omitted.

However, in embodiment 2 shown in fig. 6, the shank main body and the torque transmission annular member 52 are separate members, but a structure in which both are integrally formed may be adopted.

Industrial applicability

Thus, the shank attachment device according to the present invention has an excellent effect of being able to transmit a relatively large torque and being able to be relatively miniaturized. Use in such a shank fixation device is suitable.

Claims (5)

1. A shank fixing device for fixing a drill to a rotating portion of a drill device, the shank fixing device including a spindle and a shank, the spindle being detachably attached to the rotating portion, the spindle and the shank being detachably attached to each other, and the shank being detachably attached to the drill, wherein the shank fixing device is configured such that the spindle and the shank are detachably attached to each other, and the shank is detachably attached to the drill

Wherein, in a state where the shank is fixed to the mandrel, an engaging member provided on the mandrel engages with an engaging groove formed on a side surface of the shank to prevent the shank from moving in an axial direction away from the mandrel, and a 1 st engaging portion provided on the mandrel engages with a 1 st engaged portion provided on the shank to transmit torque of the mandrel to the shank, the shank being in contact with the mandrel to prevent the shank from moving in an axial direction toward the mandrel,

the mandrel is provided with a fixed shaft fixed on a rotating part of the drill bit device, the front end part of the fixed shaft is provided with an expanding part, the expanding part is detachably screwed on a base body of the mandrel by a screw,

the shank is detachably fixed in a shank fixing hole formed in the mandrel,

a central bit fixing hole communicating with the shank fixing hole is provided on a base body of the mandrel,

a fixing screw hole having an inner peripheral surface formed with a female screw is provided from an outer peripheral surface of the base body toward a center of the central drill fixing hole perpendicularly to the central drill fixing hole,

a fixing screw is screwed into the fixing screw hole, and the front end of the fixing screw can protrude into the central drill fixing hole,

the diameter-enlarged portion covers at least a part of the fixing screw screwed into the fixing screw hole from the outside, thereby preventing the fixing screw from dropping out of the base body.

2. The shank attachment device according to claim 1, wherein a 2 nd engaging portion provided on the shank is engaged with a 2 nd engaged portion provided on the drill in a state where the drill is fixed to the shank, so that a torque of the shank can be transmitted to the drill.

3. The shank fixation device of claim 2,

the 1 st engaging part is a concave part or a convex part, the 1 st engaged part is a convex part or a concave part,

the 2 nd engaging part is a concave part or a convex part, and the 2 nd engaged part is a convex part or a concave part.

4. The shank fixture according to claim 2 or 3, wherein the 1 st engagement receiving portion and the 2 nd engagement receiving portion are formed in a torque transmission annular member, and the torque transmission annular member and the drill are screwed to the shank in a state in which the torque transmission annular member and the drill are engaged with each other.

5. A shank fixture according to any one of claims 1 to 3,

a structure capable of detachably fixing the shank to a shank fixing hole formed in the mandrel,

a support member for limiting the projection of the engaging member into the shank fixing hole when the shank is not fixed to the shank fixing hole,

the support member is formed by the front end of a coil spring disposed in the shank fixing hole,

the base end portion of the coil spring is engaged with an engagement groove portion, and the engagement groove portion is in contact with an inner peripheral surface of the inner portion of the shank fixing hole.