JP2000326126A - Core drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a core body with single operation by arranging a locking means having a locking claw on a substrate and locking the locking claw to a locking recessed part provided in the top edge of the core body in a state where an engaging projection is at an engagement final position of an engaging groove. SOLUTION: In the process in which a core body-mounting portion 5 is inserted into the upper end portion of a core body 7, a locking claw 15 is pressed up against a compression string 13 and goes out of the core body-mounting portion 5, and the top edge of the core body abuts to a shoulder portion 4. Subsequently, a substrate 1 and the core body 7 are rotated relatively, and thereby, an engaging projection 8 moves to an engagement final position through a transverse groove portion 6b. At this time, one engaging projection 8 elastically does beyond a tubular spring pin 20 projecting to the transverse groove portion 6b and reaches the engagement final position. When the engaging projection 8 reaches the engagement final position, an engagement recessed part 10 faces just under the locking claw 15, a stopper member 14 is machined under energizing of the compression spring 13, the locking claw 15 projects to the core body-mounting portion 5 to lock to the engagement recessed part 10, and the core body 7 is locked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core drill in which a center hole is advanced by a center drill, and a large diameter hole concentric with the center drill is formed by a core body integrated with the center drill. More specifically, the present invention relates to a core drill which is capable of separating a base and a core body constituting a core drill, and which is suitable for drilling in concrete, stone, or the like while reliably maintaining a connection relationship between the base and the core body.

[0002]

2. Description of the Related Art Conventionally, various kinds of drills for drilling large-diameter holes have been developed and marketed. In order to smoothly carry out the drilling work of large diameter holes, together with the center drill,
2. Description of the Related Art A core drill is widely used in which a cylindrical core body having a drilling blade provided at a lower end edge is combined, and a center drill is used to precede a center hole, and thereafter, a large-diameter hole is formed by the core body.

As a core drill of this type, a mounting plate is provided at the lower end of a base having a shank, and a core body mounting portion having a shoulder portion stepped on an upper portion is formed around the mounting plate.
At a plurality of locations on the peripheral surface of the mounting portion of the core body, hook-shaped engagement grooves comprising a vertical groove portion and a horizontal groove portion are recessed, and the engagement groove is formed on an inner surface of an upper end portion of the core body having a perforated blade at a lower edge. An engaging projection is provided in a protruding manner in correspondence with the above, and the base and the core body are joined by inserting the core body mounting portion of the attachment plate into the upper end of the core body and engaging the engaging projection with the engaging groove. In order to maintain this coupling relationship, the mounting plate is provided with a blocking ball which is urged by a spring and protrudes into the lateral groove portion of the engagement groove to hold the engagement projection at the engagement end point. There is. As a prior art of this kind of core drill, there is one disclosed in Japanese Utility Model Publication No. 7-39527, for example.

[0004] In the core drill having such a configuration, the connection and separation of the base and the core body can be easily performed in a one-touch manner. Therefore, when drilling a concrete material or a stone material using an electric drill, after drilling, both of them are required. This is convenient because it is easy to extract a cutting lump remaining in the core after being separated.

[0005]

However, as described above, in the case of a core drill having a configuration in which the base and the core body can be connected and separated, when drilling a drilled object with only a constant rotational force, Although it is excellent in stability without changing the connection relationship during drilling work, in drilling concrete or stone using an electric drill, especially a rotary hammer drill, both vibrational impact force and rotation Since the drilling is performed simultaneously with the action, a shocking pressure acts on the core body during the drilling operation, causing the core body to rattle. This becomes a factor that makes the bonding relationship between the base and the core body unstable.

[0006] In recent years, electric drills equipped with brakes having a structure for rapidly stopping rotation have been marketed.
In the case of this type of electric drill, if a sudden brake is applied during rotation, the core body may come off due to the inertial force during rotation, which is unstable.

[0007]

Therefore, in order to solve the above-mentioned problems, in the core drill of the present invention, an attaching plate is provided at the lower end of the base, and a peripheral surface of the core body attaching portion formed around the attaching plate is provided. A plurality of engagement grooves are recessed, and an engagement projection is provided on an inner surface of an upper end portion of a cylindrical core body having a perforated blade at a lower edge, and a core body attachment portion is inserted into an upper end portion of the core body. In a core drill for connecting a base and a core body by engaging an engagement protrusion with an engagement groove, a lock means having a locking claw is provided on the base, and the engagement protrusion is provided at an engagement end point of the engagement groove. In a certain state, the locking claw is locked in a locking recess provided in the upper edge of the core body to lock the core body.

As described above, according to the core drill of the present invention, the core body is securely locked to the base body by the locking means when the base body and the core body are connected, so that the core drill can be used for a rotary hammer drill or the like. The connection between the substrate and the core body does not change during the drilling operation, and the stability is excellent.

In addition, when the engagement protrusion reaches the engagement end point of the engagement groove, the locking claw projects from the surface of the core body mounting portion and locks into the locking recess, so that the core body is securely fixed. Locking allows the core to be attached in a one-touch fashion. At the same time, the core body is automatically locked, so that workability can be improved.

The locking means comprises a stopper member fitted to the base member and moved in the axial direction of the base member under the bias of the elastic member, and a plurality of locking claws provided downward at the lower end of the stopper member. can do.

With this configuration, in a state where the core member is connected to the base member, the stopper member descends with respect to the base member under the bias of the elastic member so as to take a locked position, and the locked state of the core member is maintained. When the stopper member at the lock position is pulled up against the elastic expansion / contraction member, the locking claw is retreated from the core body attaching portion, the lock of the core body is released, and the engagement protrusion is free to move in the engagement groove. Therefore, the substrate and the core body can be separated.

The stopper member fitted to the base is always
It is urged downward by the elastic elastic member. Therefore, a compression spring can be used as the elastic member. In this case, the compression spring forms a spring accommodating space between the cylindrical main body of the stopper member slidably fitted to the base and the base, and accommodates the compression spring in the spring accommodating space so that the lower end of the spring is formed inside the cylindrical main body. It is preferable that the spring is supported by a receiving step provided on the peripheral wall surface and the upper end of the spring is supported by a retaining ring fitted to the base.

With this configuration, when the base and the core body are separated from each other, the elastic main body, that is, the cylindrical main body of the stopper member covering the compression spring is gripped with a fingertip, and the stopper member is lifted to unlock. Because you can operate
Operability is improved. Further, the compression spring does not come into contact with an external object during the drilling operation. Further, since the compression spring needs only to be a single spring that surrounds the base, the construction and processing of the components constituting the locking means related thereto are simplified. Further, when the retaining ring supporting one end of the compression spring is removed from the base, the elastic expansion member and the stopper member are pulled out above the base, so that the disassembling and assembling work of the parts can be simplified.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded front view of a core drill partially showing a cross section of an embodiment of the present invention.

In FIG. 1, a base 1 has a shank 2 at the center of the upper surface thereof, which is supported by a chuck of a drive shaft.
An attachment plate 3 is provided at the lower end of the base, and a core body attachment portion 5 is formed around the attachment plate 3 with a shoulder 4 stepped up at the top.

Engagement grooves 6 are equally distributed at three places on the peripheral surface of the core body mounting portion 5. The engagement groove 6 includes a vertical groove 6a formed in the generatrix direction from the lower end of the core body mounting portion 5, and a horizontal groove 6 formed in a hook shape in the circumferential direction following the vertical groove 6a.
b.

The core body 7 connected to the base 1 has a cylindrical shape, and the inner surface of the upper end of the core body 7 into which the core body mounting part 5 is inserted by coupling with the base 1 is connected to the surface of the core body mounting part 5. Groove 6
The core body 7 is provided with a drilling blade 9 made of a carbide tip at the lower end edge of the core body 7. In addition, a locking concave portion 10 is provided in the upper end edge portion of the core body 7 in a cut shape corresponding to a locking claw 15 described later.

A center drill 11 is attached to the center of the base 1 in the core body 7. This center drill 11
Is fitted in a drill mounting hole 1a (see FIG. 2) provided in the center of the lower surface of the base 1, and is detachably fixed by a hit screw or the like (not shown) screwed from the side of the base. . The base 1, the core body 7, and the center drill 11
Is the same as a well-known core drill.

In the present invention, the core body 7 is
Is provided. The locking means 12 includes a stopper member 14 which is fitted to the base 1 and moves in the axial direction of the base under the bias of a compression spring 13 (elastic expansion / contraction member). In the embodiment, the groove 1 extends from the periphery of the attachment plate 3, that is, from the shoulder 4 to the surface of the core body mounting portion 5, corresponding to the locking claw 15.
6, the locking claw 15 is moved to the concave groove portion 16 so as to protrude and retract from the surface of the core body attaching portion 5, and is engaged with and disengaged from the locking concave portion 10 of the core body 7. Further, in the embodiment, three locking claws 15 are provided equidistantly from the engaging groove 6 recessed in the peripheral surface of the core body mounting portion 5, and these locking claws 15 are attached to the core body 7. The outer surface of the locking claw 15 matches the outer peripheral surface of the upper end portion of the core body 7 in a state where the locking claw 15 is locked in the locking recess 10.

The compression spring 13 for urging the stopper member 14 downward forms a spring accommodating space 17 between the cylindrical main body 14a of the stopper member 14 slidably fitted to the base 1 and the base 1, and the spring accommodating space 17 One compression spring 13 surrounding the base 1 is housed therein, and the lower end of the spring is attached to the cylindrical main body 1.
The upper end of the spring is supported by a retaining ring 19 fitted to the base 1.

Further, in the embodiment, one of the engagement grooves 6 is provided with a tubular spring pin 20 (see FIG. 2) which is resiliently variable in diameter so as to cross the lateral groove 6b. The tubular spring pin 20 is fitted in a receiving hole 21 provided in parallel with the base axis from below the plate in the vicinity of the peripheral edge of the mounting plate 3 and the peripheral surface thereof is formed into a lateral groove 6 b of the engaging groove 6.
The engaging projections 8 of the core body 7
When moving through the lateral groove 6b, the tubular spring pin 20 elastically rides over the tubular spring pin 20 to reach the engagement end point. In this state, the tubular spring pin 20 exerts its elasticity and presses against the engaging projection 8 surface of the core body 7. Thus, the engagement protrusion 8 is settled at the engagement end point.

With reference to FIGS. 3 and 4, the manner in which the base 1 and the core 7 are joined in the above configuration will be described.

The vertical groove 6a of the engaging groove 6 having the shank 2
When the base 1 is pressed against the core body 7 as shown in FIG. 3, when the core body mounting portion 5 is fitted into the upper end of the core body 7, the locking claw 15 13, the core body is withdrawn from the core body mounting portion 5 and comes into contact with the shoulder 4 at the upper edge of the core body. Subsequently, when the base 1 and the core body 7 are relatively rotated, the engaging projections 8
To reach the engagement end point. At this time, one engagement projection 8 elastically rides over the tubular spring pin 20 projecting into the lateral groove 6b and reaches the engagement end point (see FIG. 2).

At the same time as the engagement projection 8 reaches the engagement end point,
As shown in FIG. 4, the locking recess 10 faces directly below the locking claw 15, the stopper member 14 descends under the bias of the compression spring 13, and the locking claw 15 projects to the core body mounting portion 5 and locks. The core body 7 is locked by being locked in the recess 10. These operations are continuous, and the mounting of the core body 7 can be performed in a one-touch manner, and at the same time, the core body 7 is automatically locked.

In order to separate the base 1 and the core body 7 from each other, the stopper 1 is pulled up against the compression spring 13 to unlock the core body 7. The rotation is performed relatively.

[0027]

The present invention is embodied in the form as described above. According to the present invention, the mounting of the core body can be performed in a one-touch manner, and the core body is automatically locked at the same time.
Workability can be improved. Also, unless the lock release operation for raising the stopper member against the elastic elastic member (compression spring) is performed artificially, the connection relationship between the base and the core body is kept unchanged. Also realizes stable and reliable drilling. Further, since the stopper member and the elastic expansion / contraction member constituting the locking means are outside the base and rationally assembled to the base, the structure and processing are simplified, and the assembling work is also simplified.

[Brief description of the drawings]

FIG. 1 is an exploded front view of a core drill partially showing a cross section of an embodiment of the present invention.

FIG. 2 is a transverse sectional view taken along the line AA of FIG. 1;

FIG. 3 is an explanatory view of a connection procedure of a base and a core body.

FIG. 4 is an explanatory view of a connection procedure of a base and a core body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Shank 3 Attachment plate 4 Shoulder part 5 Core body attachment part 6 Engagement groove 6a Vertical groove part 6b Lateral groove part 7 Core body 8 Engagement projection 9 Drilling blade part 10 Locking concave part 11 Center drill 12 Lock means 13 Elasticity Telescopic member 14 Stopper member 14a Cylindrical main body 15 Engagement claw 16 Depressed groove 17 Housing space 18 Receiving step 19 Stop ring 20 Tubular spring pin 21 Housing hole

Claims (4)

[Claims] 1. A cylindrical core having a mounting plate provided at a lower end of a base, engaging grooves formed at a plurality of positions on a peripheral surface of a core body mounting portion formed around the mounting plate, and a perforation blade at a lower end edge. In a core drill, an engagement protrusion is protruded from an inner surface of an upper end portion of a body, and a core body attachment portion is inserted into an upper end portion of the core body, the engagement protrusion is engaged with the engagement groove, and the base and the core body are joined. A locking means having a locking claw is provided on the base, and the locking claw is locked in a locking recess provided in an upper end edge of the core body in a state where the engagement protrusion is at an engagement end point of the engagement groove. A core drill characterized by locking the core body. 2. When the base body and the core body are connected, the engaging claw projects to the engagement end surface of the core body at the same time as the engaging projection reaches the engagement end point of the engaging groove, and is engaged with the locking recess. The core drill according to claim 1, wherein the core drill is locked. 3. A locking means, comprising: a stopper member fitted to the base and moved in the axial direction of the base under the bias of the elastic member; and a plurality of locking claws provided downward at the lower end of the stopper member. The core drill according to claim 1, wherein the core drill is formed. 4. An elastic expansion and contraction member is formed of a compression spring, and a spring accommodating space is formed between the cylindrical main body of the stopper member and the base.
A compression spring is accommodated in the spring accommodating space, and a lower end of the spring is supported by a receiving step provided on an inner peripheral wall surface of the cylindrical main body, and an upper end of the spring is supported by a retaining ring fitted to the base. The core drill according to claim 1.