JPH0518062Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is a hammer drill for performing drilling operations by transmitting striking motion and rotational motion to the bit, and a hammer drill for removably inserting the bit. This invention relates to a bit insertion device.

(Prior art) As a conventional technology, there is, for example, Japanese Patent Application Laid-open No. 4373/1983.

(Problems to be Solved by the Invention) Conventional hammer drills have a problem in that the mechanism for locking and unlocking the inserted state of the bit is complex and prone to malfunction.

The object of the present invention is to provide a bit insertion device for a hammer drill that has a simple mechanism and operates accurately.

(Means for Solving the Problems) The bit insertion device of the present invention has a keyhole inserted through a barrel having a bit hole into which a bit is inserted/removed. A key to be engaged and disengaged is inserted into the key groove of the bit, and an engaging portion that is open on both sides is recessed on the outer end surface of the key, and the key is fitted onto the barrel and extends in the axial direction of the barrel, facing the key. The inner circumferential surface of the movable ring is installed so that the movable ring can be moved forward and backward, and when the movable ring is retracted, the movable ring is disposed so as to be able to fit into the engaging portion, and when the movable ring is advanced, the movable ring is in circumferential contact with a part of the key. A projecting edge is formed on the inner peripheral surface of the movable ring to restrict the movement of the key outward from the keyway, and when the movable ring is retracted, a part of the key is received and the keyway is closed. A relief groove is formed adjacent to the protruding edge to allow the key to move outward.

(Function) When the movable ring, which is installed so that it can move forward and backward in the axial direction of the barrel in opposition to the key that engages and disengages from the keyway of the bit, and which is fitted externally to the barrel, moves, the inner circumferential surface of the movable ring A projecting edge formed on a portion of the key circumscribes a portion of the key to restrict movement of the key outward from the keyway, and the key is held in a state engaged with the keyway. The movable ring is moved to a position where the projecting edge faces an engaging portion recessed in the outer end surface of the key, and a portion of the key faces a relief groove formed on the inner peripheral surface of the movable ring. Then, the key can be moved outward from the keyway, and the key can be removed from the keyway.

(Example) Next, an example of the present invention will be described with reference to the drawings.

A motor 2 that is rotatably driven to transmit rotational motion and striking motion to the bit B is housed horizontally in the motor housing 1, and a fan 3 is fitted onto the motor shaft 2a, and a pinion 4 is mounted on the motor shaft 2a. is formed.

The gear housing 5 is connected to the front of the motor housing 1, and a barrel 6 having a bit hole 6a for removably inserting a bit B is rotatably supported in the front part thereof, and a barrel 6 is rotatably supported in the rear part thereof. The crank housings 7 are arranged in parallel.

The crankshaft 8 is rotatably mounted horizontally in the lower part of the gear housing 5, and a pinion 8a is mounted at the front and rear of the crankshaft 8.
and a gear 8b meshed with the pinion 4 of the motor shaft 2a, and a crank pin 9 is eccentrically protruded from the rear end surface of the gear 8b.

Pistons 10 are tightly fitted into cylinders 11 arranged in parallel in the crank housing 7 so as to be able to slide in the axial direction, and are formed in the shape of a hollow cylinder with an open front, and a connecting hole 12 is formed through each cylinder at the rear end. A pair of left and right connecting pieces 10a, 10a protrude in parallel.

The crank lever 13 is connected to a pin 1 in the crank housing 7 in order to convert the rotational movement of the crankshaft 8 into a reciprocating movement and transmit it to the piston 10.
4, the base 1
A sliding surface 16 is formed at the tip of the base portion 13a in a concave arc shape for horizontally slidingly fitting a semi-cylindrical crank joint 15 loosely fitted onto the crank pin 9, while the base end of the base portion 13a A round bar-shaped connecting rod 13b is provided in a substantially perpendicular manner to protrude from the crankshaft in order to slidably insert the cylindrical piston joint 17 loosely inserted into the connecting hole 12 of both connecting pieces 10a of the piston 10. The eccentric rotation of the pin 9 causes the crank lever 13 to swing back and forth, and the piston 10 is repeatedly moved forward and backward in the axial direction.

The rear striker 18 is tightly fitted into the front part of the piston 10 so as to be able to slide in the axial direction, and when the piston 10 moves forward, the air chamber 10b is pressurized and moves forward, and when the piston 10 moves backward, the air chamber 10b is closed. The pressure inside 10b is reduced and it retreats.

The front striker 19, which is interposed between the bit B and the rear striker 18 in order to transmit the striking action of the rear striker 18 to the bit B, is inserted into a slide hole 6b that is continuously bored behind the bit hole 6a of the barrel 6. They are fitted so that they can slide in the axial direction, and each time the rear striker 18 moves forward, the bit B moves to the front striker 19.
gets hit repeatedly.

In order to transmit the rotation of the crankshaft 8 to the barrel 6, a gear 20 is fitted to the rear end of the barrel 6 so as to be slidable in the axial direction. The clutch surface 29 formed on the front surface of the flange 6c at the rear end of the barrel 6 is releasably engaged with the clutch surface 29 formed on the front surface of the flange 6c at the rear end of the barrel 6.
A clutch surface 20a is formed to transmit a rotational motion of 0 to the barrel 6, and when an excessive rotational load is transmitted to the barrel 6 via the bit B, the clutch surface 20a is
The clutch surface 20a of the barrel 6 is the clutch surface 20a of the barrel 6.
9 is repeatedly engaged and engaged, and the gear 20 is idled while moving forward and backward.

In order to transmit the rotation of the barrel 6 to the bit B, the bit B is releasably engaged in both key grooves B1 and B1, and is engaged and disengaged from the key groove B1 by moving the barrel 6 in the radial direction. A pair of upper and lower keys 2
Numerals 1 and 21 are inserted into a pair of upper and lower key holes 22 which are respectively penetrated near the tip of the barrel 6, and which are immovable in the axial direction of the barrel 6, but movable in the radial direction of the barrel 6, and are inserted into the bit hole 6a. are fitted and inserted so as to prevent them from coming off, and a locking piece 21a, 21a is provided rotationally symmetrically protruding from one side of each outer end, while an engaging portion 21 is provided on each outer end surface 21c.
b, 21b are recessed in a box-like shape with both sides open, and when the key 21 is engaged with the keyway B1, the outer end surface 21c of the key 21 is substantially aligned with the outer circumferential surface of the barrel 6.

A movable ring 23 formed in a substantially cylindrical shape is located near the front end of the barrel 6 in order to restrict and allow the movement of both keys 21 outward from the keyway B1 by moving the barrel 6 forward and backward in the axial direction. The spring 24 is fitted externally so as to be slidable in the axial direction and is always fitted with a spring 24.
A relief groove 23a is circumferentially recessed near the center of the inner circumferential surface, and a front protruding edge 23 is provided near the front and rear ends of the inner circumferential surface.
b and a rear protruding edge 23c are respectively formed to protrude, and when the key 21 is engaged with the key groove B1, the relief groove 23a is opposed to the engaging part 21b of the key 21, and the front and rear protruding edges 23b, 23c are formed to protrude from the key 21. The keyway B is in contact with the front end and the rear end of the outer peripheral surface of the
While the movement of the key 21 to the outside of 1 is restricted,
When the movable ring 23 is pushed backward against the spring 24, the front protruding edge 23b is opposed to the engaging portion 21b of the key 21, allowing the key 21 to move outward of the keyway B1, and the bit B can be inserted into the bit hole 6a of the barrel 6 and pulled out from the bit hole 6a.

The change ring 25, which is fitted onto the outside of the movable ring 23 so that it can rotate and move together in order to move the movable ring 23 in the axial direction, has a protrusion 23d that protrudes from the outer peripheral surface of the rear end of the movable ring 23, and , the spring 2 is locked to the upper edge of the front end of the movable ring 23.
4, and its front edge is locked by a protrusion 26a of a rubber cap 26 fitted onto the front end of the barrel 6, and is movable by releasing and pushing the change ring 25. By controlling the movement of the ring 23 in the axial direction, the engagement between both keys 21 and both key grooves B1 of the bit B can be locked or released.

Next, the operation and effects of the embodiment having the above configuration will be explained.

In this example, a key hole 22 is provided through the barrel 6, which has a bit hole 6a into which the bit B is inserted and removed, and a key that engages and disengages from the keyway B1 of the bit B by moving the barrel 6 in the radial direction. 21 is inserted into the key 21, and an engaging portion 21b which is open on both sides is recessed on the outer end surface of the key 21, and the key 21 is fitted onto the outside of the barrel 6 and is opposed to the key 21 so that the barrel 6 can be moved forward and backward in the axial direction. The inner peripheral surface of the installed movable ring 23 is opposed so that it can fit into the engaging portion 21b of the key 21 when the movable ring 23 is retracted, and is in circumferential contact with a part of the key 21 when the movable ring 23 is advanced. A front protruding edge 23b is formed to restrict movement of the key 21 outward of the groove B1, and a movable ring 23 is formed on the inner peripheral surface of the movable ring 23.
When the key 21 is retracted, a part of the key 21 is received and the key groove B
Relief groove 2 that allows the key 21 to move outward from 1
3a is formed adjacent to the front protrusion 23b.

Therefore, by moving the movable ring 23 in the axial direction, the engagement between both keys 21 and both key grooves B1 can be easily and accurately locked and unlocked, and the operation of attaching and detaching bit B to and from the barrel 6 can be performed easily and accurately. In addition to simplifying the bit B insertion mechanism, the present invention has the effect of reliably preventing the risk of the key 21 being loose and detached from the keyway B1 during operation, and the bit B being accidentally removed. be.

In addition, the protrusion 23b of the movable ring 23 is attached to the key 21.
Since the engaging portion 21b for engaging and removing the bit is recessed, the movement stroke of the movable ring 23 can be shortened and the inserted state of the bit can be accurately locked and unlocked.

(Effects of the invention) Since the present invention is constructed as described above, movement of the key outward from the keyway of the bit can be controlled or permitted by moving the movable ring forward or backward. It is possible to accurately switch the bit with a single touch to prevent the bit from coming off, or to release the state where the bit is prevented from coming off.

In addition, instead of moving the movable ring to a position where it is removed from the key, you can simply move the movable ring from a position where its flange circumscribes a part of the key to a position where the flange faces the engaging part of the key. It is possible to release the movement restriction state for the key, reduce the moving distance when moving the movable ring, and speed up the switching operation between the movement restriction state and the movement restriction release state for the key.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a side sectional view of the main part, FIG. FIG. 4 is a cross-sectional view taken along the line Y--Y in FIG. 2, and FIG. 5 is an exploded perspective view of the crank mechanism. 6... Barrel, 6a... Bit hole, 21... Key, 21b... Engaging portion, 23... Movable ring, B
... Bit, B1... Keyway.

Claims (1)

[Scope of utility model registration request] A key is inserted into a key hole that is inserted through a barrel having a bit hole into which a bit is inserted and removed, and which is engaged with and removed from the key groove of the bit by moving the barrel in the radial direction. is provided with an engaging portion that is open on both sides, and a movable ring that is fitted onto the barrel and is installed opposite to the key so as to be able to move the barrel forward and backward in the axial direction. a protrusion that is arranged so as to be able to fit into the engaging portion when the movable ring is retracted, and that circumscribes a portion of the key when the movable ring is advanced to restrict movement of the key outward from the keyway; and a relief groove is formed on the inner circumferential surface of the movable ring to receive a part of the key when the movable ring is retracted, and to allow the key to move outward from the keyway. A bit insertion device for a hammer drill, characterized in that the bit insertion device is formed adjacent to.