JP7574063B2 - Impact tools - Google Patents

Description

The present invention relates to an impact tool used to drive drift pins into wood joints, etc.

In wooden construction, a method is known in which a metal fitting is attached to one piece of wood, and a drift pin is driven into the other piece of wood, penetrating the metal fitting, to join the pieces of wood. The drift pins are driven by a worker using a hammer, but if there are a large number of drift pins, it takes time and places a heavy burden on the worker. Therefore, Patent Document 1 discloses an invention of a driving machine in which an adapter equipped with a tip structure for driving drift pins is attached to an air hammer. This adapter includes a snap (shaft) that is attached to the air hammer, a guide (sleeve) that is attached to the snap and can move relatively by a predetermined stroke, and a spring (coil spring) that is attached to the snap and the guide and biases the guide to a forward position.
When the air hammer is driven with the rear end of the drift pin inserted into the tip of the guide protruding from the snap, the snap is repeatedly struck by the piston of the air hammer, driving the drift pin into the wood. When the snap moves forward by the stroke, its front end surface becomes flush with the front end surface of the guide, allowing the drift pin to be driven completely into the wood.

JP 2008-161908 A

The conventional driving machines described above use an air hammer, so in addition to the air hammer, a compressor and a hose must also be prepared. This makes installation and removal cumbersome, and since it is connected to a hose, it is difficult to handle, which may reduce the efficiency of the driving work.

Therefore, the present invention aims to provide an impact tool that is easy to handle and can improve the efficiency of driving work.

In order to achieve the above object, the present invention provides an impact tool, comprising: a housing that houses a motor and has a handle portion;
a battery detachable from the housing;
An impact mechanism that is driven by the motor;
a drift pin driving mechanism including: a shaft disposed in front of the impact mechanism and to which impact is transmitted by the impact mechanism; a sleeve mounted on the shaft so as to be movable relative to the shaft in the forward and backward directions by a predetermined stroke, the sleeve having a front end into which a rear end of a drift pin can be inserted; and a coil spring that biases the sleeve toward a forward position which is the front end of the stroke ;
The housing has a drive side housing which includes the impact mechanism and the drift pin driving mechanism, and a handle side housing which is connected to the drive side housing so as to be able to move relatively over a predetermined forward and backward stroke and which includes the handle portion, and is characterized in that an elastic means is provided between the drive side housing and the handle side housing for urging the handle side housing to a retracted position which is the rear end of the forward and backward stroke .
Another aspect of the present invention is characterized in that, in the above configuration, at least a portion of the handle portion is located on the axis of the shaft behind the striking mechanism.
Another aspect of the present invention is characterized in that, in the above configuration, it further comprises driving end detection means for detecting completion of driving of the drift pin into the workpiece.
Another aspect of the present invention is characterized in that, in the above configuration, the driving end detection means includes a sensor that non-contact measures the distance between the driven material and the housing which advances as the drift pin is driven in.
Another aspect of the present invention is characterized in that, in the above configuration, when the driving end detection means detects the completion of driving of the drift pin, the driving of the motor is stopped.
Another aspect of the present invention is characterized in that, in the above configuration, when driving in the drift pins begins, the rotation speed of the motor starts from a low state and gradually increases.
Another aspect of the present invention, in the above configuration, is characterized in that the motor is driven at a rotation speed including a plurality of constant rotation states that are gradually increased.
Another aspect of the present invention is characterized in that, in the above configuration, a speed change mechanism is provided that can arbitrarily change the rotation speed of the motor.
Another aspect of the present invention is characterized in that, in the above configuration, the drift pin driving mechanism is a detachable adapter.
Another aspect of the present invention is characterized in that, in the above-mentioned configuration, the shaft is elastically supported in the radial direction within the sleeve.

According to the present invention, by using a battery as the drive unit, it is possible to improve the ease of handling and the efficiency of the driving work.
According to another aspect, in which at least a portion of the handle portion is located on the axis of the shaft behind the striking mechanism, the drift pin can be easily pushed in, and the pressing force from the handle portion can be efficiently transmitted to the drift pin.
In particular, the housing has a drive side housing which includes the impact mechanism and drift pin driving mechanism, and a handle side housing which is connected to the drive side housing so that it can move relative to it over a predetermined forward and backward stroke and which includes a handle portion, and an elastic means is provided between the drive side housing and the handle side housing for urging the handle side housing to a retracted position which is the rear end of the forward and backward stroke, so that vibrations generated by the impact mechanism and drift pin driving mechanism are less likely to be transmitted to the handle portion, resulting in a good feel when working.
According to another embodiment including a driving end detection means for detecting the completion of driving the drift pin into the workpiece, it is possible to quickly take measures such as stopping the drive of the motor when driving is completed.
In another embodiment, the end-of-driving detection means includes a sensor that non-contact measures the distance between the material being driven and the housing that advances as the drift pin is driven in, so that the end-of-driving detection means does not interfere with work.
According to another embodiment in which the driving of the motor is stopped when the driving end detection means detects the completion of driving of the drift pin, no impact is applied after the driving is completed, which leads to the protection of the material being driven.
According to another embodiment in which the motor speed is controlled so as to gradually increase from a low speed at the start of driving in the drift pins, the impact at the start of driving in the drift pins is reduced.
According to another embodiment having a speed change mechanism that can arbitrarily change the rotation speed of the motor, the number of strikes that is most convenient for work can be selected, improving ease of use.
According to another aspect in which the drift pin driving mechanism is a detachable adapter, maintenance and replacement of the adapter can be easily performed.
According to another aspect in which the shaft is elastically supported in the radial direction within the sleeve, the shaft is less likely to come into contact with the sleeve, and the noise generated when the drift pin is driven in can be reduced.

FIG. 1 is a central vertical cross-sectional view of an electric hammer equipped with a drift pin driving adapter of the first embodiment. FIG. 13 is an enlarged view of the drift pin driving adapter portion. FIG. 13 is an explanatory diagram showing the completed state of driving in the drift pins. 1A and 1B are explanatory diagrams of a modified example that employs a drift pin holding mechanism (magnet); FIG. 1A shows a cross section of the magnet portion, and FIG. 1B shows a central longitudinal section. FIG. 13 is an explanatory diagram of a modified example in which a drift pin retention mechanism (O-ring) is adopted. 13 is an explanatory diagram of a modified example in which a sound absorbing mechanism is adopted. FIG. 13 is an explanatory diagram of a modified example in which a protective portion is provided on the sleeve. FIG. 13A and 13B are explanatory diagrams showing a modified example of the stopper mechanism. 11A and 11B are explanatory diagrams showing a modified example of the stopper mechanism, in which (A) shows a cross section of the anti-rotation pin portion and (B) shows a side view. 13 is an explanatory diagram showing a state in which the driving of the drift pin is completed in the modified example of the stopper mechanism. FIG. FIG. 13 is a central vertical cross-sectional view (initial position) of a drift pin driving machine of the second embodiment. FIG. 13 is an enlarged view of the driving mechanism (initial position). FIG. 13 is an enlarged view of the striking mechanism (striking position). FIG. 13 is an enlarged view of the driving mechanism (driving completed state).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Form 1]
Fig. 1 is a central vertical cross-sectional view showing an example of a drift pin driving adapter (hereinafter referred to as "adapter") 1 and an electric hammer 50, which is an example of an impact tool equipped with the adapter 1. Fig. 2 is an enlarged view of a portion of the adapter 1. Here, the left side will be described as the front.

(Description of the drift pin insertion adapter)
The adapter 1 includes a shaft 2 , a sleeve 3 , and a coil spring 4 .
The shaft 2 is made of metal and has a circular cross section, and includes a front portion 5, an intermediate portion 6, and a rear portion 7. The front portion 5 and the rear portion 7 have the same diameter, and the intermediate portion 6 is formed to have a larger diameter than the front portion 5 and the rear portion 7. The front end surface 5a of the front portion 5 is a spherical surface that bulges forward. A flange 8 having a larger diameter than the intermediate portion 6 is formed between the front portion 5 and the intermediate portion 6. A rotation prevention pin 9 is driven in the radial direction into the intermediate portion 6. A disk-shaped stopper 10 having a larger diameter than the flange 8 is mounted on the rear portion 7. The stopper 10 is fixed in the axial direction by a circlip 11 that engages with the rear portion 7 at a position where it abuts against the rear end of the intermediate portion 6. A pair of grooves 12, 12 extending forward from the rear end surface and a pair of recesses 13, 13 extending in the front-rear direction are formed on the outer periphery of the rear end of the rear portion 7 at point symmetric positions centered on the axis L of the shaft 2, with a phase difference of 90 degrees from each other.

The sleeve 3 is a metallic cylinder into which the shaft 2 is loosely inserted, and has a small diameter hole 15 at its front part and a large diameter hole 16 at its rear part, which are coaxially formed. A ring-shaped throttle section 17 is formed in the middle of the small diameter hole 15, into which the front part 5 of the shaft 2 is loosely inserted. The part of the small diameter hole 15 in front of the throttle section 17 forms a tapered hole section 18 whose diameter increases as it extends forward.
The large diameter hole 16 has a diameter that allows the flange 8 of the shaft 2 to be loosely inserted. A metallic inner sleeve 19 is press-fitted from the rear into the large diameter hole 16 behind the flange 8 to prevent the flange 8 from coming off. The inner sleeve 19 has a flange portion 20 at its rear end that abuts against the rear surface of the sleeve 3 in a press-fitted state. An engagement groove 21 that engages with the anti-rotation pin 9 provided in the intermediate portion 6 is formed on the inner circumference of the inner sleeve 19 over the entire axial length. The engagement between the anti-rotation pin 9 and the engagement groove 21 restricts the rotation of the shaft 2 and the sleeve 3 relative to each other. The sleeve 3 is movable back and forth relative to the shaft 2 with a stroke between an advanced position where the inner sleeve 19 abuts against the flange 8 and a retreated position where a step portion 22 formed between the small diameter hole 15 and the large diameter hole 16 abuts against the flange 8.

The coil spring 4 is mounted on the front portion 5 inside the sleeve 3. The front end of the coil spring 4 abuts against the narrowed portion 17, and the rear end of the coil spring 4 abuts against the flange 8.
Therefore, the sleeve 3 is normally biased by the coil spring 4 to a forward position where the inner sleeve 19 abuts against the flange 8. In this forward position, the front end surface 5a of the front portion 5 of the shaft 2 is located forward of the narrowed portion 17 and protrudes into the tapered hole portion 18.
2, the axial distance D1 between the front end face of the stopper 10 and the rear end face of the inner sleeve 19 is equal to the axial distance D2 between the front end face 5a of the shaft 2 and the front end face of the sleeve 3. In addition, the distance D1 is also equal to the axial distance D3 between the step portion 22 and the front end face of the flange 8.

(Explanation of the electric hammer)
The electric hammer 50 includes a housing 50a, which is made up of a main body housing 51 and a motor housing 52. The main body housing 51 houses an impact mechanism 53 and extends in the front-rear direction, which is the direction of the impact axis. The motor housing 52 is integrally joined to the lower side of the main body housing 51 and houses a brushless motor 54 with an output shaft 55 facing upward. The output shaft 55 protrudes into the main body housing 51.
The electric hammer 50 further includes, as the housing 50a, an outer housing 56 and a handle housing 57. The outer housing 56 extends in the front-rear direction and covers the outside of the main housing 51. The handle housing 57 is integrally connected to the rear side of the outer housing 56 and is provided from the rear of the outer housing 56 to below the motor housing 52.

The handle housing 57 includes a handle section 58, a battery mounting section 59, and a controller storage section 60. The handle section 58 extends in the vertical direction and includes a connecting section 61 on the front side that is connected to the rear end of the outer housing 56 and covers the rear of the main body housing 51 from the rear. The handle section 58 includes a switch 62 and a switch lever 63. The battery mounting section 59 is formed at the lower end of the handle section 58. The controller storage section 60 is continuous with the front side of the battery mounting section 59 and is formed by wrapping around to the lower side of the motor housing 52. A locking section 64 is formed at the upper end of the front surface of the controller storage section 60 facing backward. A locking recess 65 that locks the locking section 64 from the front is formed at the lower end of the front surface of the motor housing 52.
A battery pack 66 serving as a power source can be slidably mounted from the rear into the battery mounting section 59. The battery mounting section 59 is provided with a terminal block 67 to which the battery pack 66 is electrically connected.
A controller 68 having a control circuit board is housed in the controller housing 60 in an inclined position with its front portion lower than its rear portion.

The impact mechanism 53 includes a cylindrical tool holder 70 and a cylinder 71. The tool holder 70 is held on the front side of the main housing 51 and extends in the front-rear direction. The cylinder 71 is held on the rear side of the main housing 51 and extends coaxially with the tool holder 70 in the front-rear direction.
A crankshaft 72 is supported in the vertical direction behind the cylinder 71 within the main housing 51. An eccentric pin 73 is provided facing upward at the top of the crankshaft 72, and a gear 74 is provided at the bottom of the crankshaft 72. The gear 74 meshes with a pinion 75 provided at the upper end of the output shaft 55.
A piston 76 is accommodated in the cylinder 71 so as to be movable back and forth. The piston 76 is connected to the eccentric pin 73 via a connecting rod 77. A striker 79 is accommodated in the cylinder 71 in front of the piston 76 via an air chamber 78 so as to be movable back and forth. An impact bolt 80 is provided in front of the striker 79 and in the tool holder 70. A pair of balls 81, 81 that engage with recesses 13, 13 provided in the rear part 7 of the adapter 1 are provided at the front end of the tool holder 70. An operating sleeve 82 that is biased forward to maintain the engagement state of the balls 81, 81 with the recesses 13, 13 is provided at the front end of the tool holder 70.

The outer housing 56 and the handle housing 57 are provided so as to be movable forward and backward relative to the main body housing 51 and the motor housing 52 .
A first coil spring 83 is provided in the front-rear direction between the main body housing 51 and the handle portion 58. The first coil spring 83 is fitted at both ends inside the connecting portion 61 and straddles a front boss 84 and a rear boss 85 provided on the rear surface of the main body housing 51 and the front surface of the handle portion 58, respectively. There may be one first coil spring 83, or multiple first coil springs 83 may be arranged side by side in the left-right direction.
A second coil spring 86 is also provided between the motor housing 52 and the controller accommodating portion 60. A protruding piece 87 that protrudes downward into the controller accommodating portion 60 is provided on the underside of the motor housing 52. A receiving rib 88 is provided inside the controller accommodating portion 60, standing behind the protruding piece 87. The second coil spring 86 is held in the front-rear direction between the protruding piece 87 and the receiving rib 88.
In the normal state, the outer housing 56 and the handle housing 57 are elastically biased by the first and second coil springs 83, 86 to the retracted position shown in FIG. 1 in which the locking portion 64 of the controller accommodating portion 60 abuts against the locking recess 65 of the motor housing 52.

A speed change dial 89 is provided on the lower part of the motor housing 52 behind the motor 54. The controller 68 drives the motor 54 at a rotation speed (number of strikes) selected by rotating the speed change dial 89.
A sensor 90 is provided facing forward on the upper part of the motor housing 52 in front of the motor 54. The sensor 90 irradiates a laser beam forward and receives the reflected light to measure the distance to an object. A measurement signal is input to the controller 68.
A light 91 that illuminates the area in front of the tool holder 70 is provided below the motor housing 52 and on the front surface of the controller accommodating portion 60 .

(Drift pin insertion)
In the adapter 1 and the electric hammer 50 configured as described above, the operation sleeve 82 is retracted at the front end of the tool holder 70 to release the pressure on the balls 81, 81. In this state, the rear part 7 of the shaft 2 of the adapter 1 is inserted into the front end of the tool holder 70 instead of the bit. At this time, if a pair of protrusions (not shown) is formed on the inner peripheral surface of the tool holder 70, the grooves 12, 12 of the rear part 7 are inserted in alignment with the phase of the protrusions. Then, the recesses 13, 13 are positioned inside the balls 81, 81, respectively, and when the operation sleeve 82 is released from retraction and advanced, the operation sleeve 82 presses the balls 81, 81 toward the axial center of the tool holder 70. Thus, the balls 81, 81 are fitted into the recesses 13, 13, and the shaft 2 is attached in a state where it is prevented from coming off and from rotating. However, the shaft 2 can move back and forth with the stroke of the balls 81, 81 moving relatively within the recesses 13, 13.

If there is no ridge on the inner peripheral surface of the tool holder 70, the balls 81, 81 and the recesses 13, 13 may not be in phase with each other even if the rear part 7 of the shaft 2 is inserted into the tool holder 70 and the operating sleeve 82 is advanced. In this case, by rotating the adapter 1, the pressed balls 81, 81 will engage with the recesses 13, 13. Here, since the shaft 2 is integrated with the sleeve 3 in the rotation direction via the anti-rotation pin 9 and the inner sleeve 19, if the sleeve 3 is grasped and rotated, the shaft 2 will rotate accordingly. Therefore, even if the shaft 2 is not grasped directly, the shaft 2 can be easily rotated by operating the sleeve 3 to engage the balls 81, 81 with the recesses 13, 13.

The handle portion 58 of the electric hammer 50 with the adapter 1 attached to the tool holder 70 is thus grasped, and the tapered hole portion 18 of the sleeve 3 is placed over the rear end 101 of the drift pin 100, the front end of which is shallowly inserted into the driving position of the workpiece W, as shown in Figures 1 and 2. Then, the rear end 101 of the drift pin 100 is accommodated in the tapered hole portion 18 and abuts against the front end surface 5a of the shaft 2, and the shaft 2 is aligned in a substantially straight line with the drift pin 100. Now, when the electric hammer 50 is pushed forward with the hand grasping the handle portion 58, the shaft 2 moves relatively backward within the tool holder 70, engaging the balls 81, 81 with the front ends of the recesses 13, 13, and the rear portion 7 abuts against the impact bolt 80. Next, the outer housing 56 and the handle housing 57 move forward against the biasing forces of the first and second coil springs 83, 86.

When the switch lever 63 is pressed to turn the switch 62 ON, the controller 68 drives the motor 54. However, the controller 68 does not drive the motor 54 at the rotation speed set by the speed change dial 89 from the time of startup, but executes a soft start in which the rotation speed is gradually increased from a low rotation speed for a predetermined period of time during startup, and then drives the motor 54 at the set rotation speed.
A lock-on button 92 that holds the switch lever 63 in the pressed position is provided on the upper part of the handle portion 58. Therefore, if the lock-on button 92 is pressed while the switch lever 63 is pressed, the motor 54 continues to drive even if the switch lever 63 is not kept pressed.

When the output shaft 55 of the motor 54 rotates, the crankshaft 72 rotates via the pinion 75 and the gear 74. Thus, the piston 76 moves back and forth via the connecting rod 77. This causes the striker 79 to move back and forth in tandem via the air chamber 78. The striker 79 moves back and forth to strike the impact bolt 80, and indirectly strikes the shaft 2. Thus, the drift pin 100 is driven into the workpiece W. At this time, the spherical front end surface 5a of the shaft 2 abuts against the rear end 101 of the drift pin 100, so that the impact is always transmitted to the axis of the drift pin 100. Furthermore, even if the adapter 1 vibrates, the deviation from the drift pin 100 can be absorbed within the tapered hole portion 18, so that the impact to the drift pin 100 is transmitted efficiently.
When driving, the hand gripping the handle portion 58 is positioned rearward on the axis L of the shaft 2 (axis L of the tool holder 70). Therefore, the forward pressing force by the operator is transmitted to the shaft 2 without loss. Also, the outer housing 56 and the handle housing 57 move forward against the biasing forces of the first and second coil springs 83, 86 and do not come into contact with the main body housing 51 and the motor housing 52. Therefore, vibrations transmitted to the outer housing 56 and the handle housing 57 during driving are suppressed, and vibrations transmitted to the hand gripping the handle portion 58 are reduced.

As the driving proceeds, the electric hammer 50 and the adapter 1 move forward, and the front end of the sleeve 3 comes into contact with the surface of the material W to be driven. Then, the sleeve 3 remains in place and the shaft 2 moves forward while continuing the driving. Thus, as shown in Figure 3, the stopper 10 comes into contact with the flange portion 20 of the inner sleeve 19. At this time, the flange 8 also comes into contact with the step portion 22, and the front end surface 5a is in the same front-to-back position as the front end surface of the sleeve 3. In this way, the rear end surface of the drift pin 100 becomes flush with the surface of the material W to be driven, and the drift pin is completely driven into the material W to be driven.
The worker visually checks that the stopper 10 has come into contact with the flange portion 20 of the inner sleeve 19 and releases the electric hammer 50, completing the driving operation.
However, instead of visual inspection using the stopper 10, the controller 68 may monitor the measurement signal from the sensor 90, and when the measurement signal determines that the distance from the workpiece W has reached the driving completion distance of the drift pin 100, the controller 68 may determine that driving is complete and stop driving the motor 54.
During the driving operation, the worker can support the adapter 1 with the other hand, but since the coil spring 4 is inside the sleeve 3 and the entire sleeve 3 is exposed, the worker can easily support it by grasping the sleeve 3. In addition, there is less risk of foreign matter such as wood chips generated from the material W being driven in getting inside.

(Effects of the invention relating to the adapter and the electric hammer equipped with the adapter)
The adapter 1 and electric hammer 50 of the above-mentioned embodiment 1 include a shaft 2 capable of striking a drift pin 100, a sleeve 3 that is mounted on the shaft 2 so as to be movable in the front-rear direction relative to the shaft 2 by a predetermined stroke and into whose front end the rear end 101 of the drift pin 100 can be inserted, and a coil spring 4 that biases the sleeve 3 to a forward position that is the front end of the stroke. The coil spring 4 is disposed inside the sleeve 3.
This configuration maintains good operability and durability without foreign matter getting caught and interfering with the relative movement of the sleeve 3, or without external impact damaging the coil spring 4. In addition, since the sleeve 3 can be securely gripped, the device is easy to use.

The adapter 1 is provided with a rotation-stop pin 9 and an engagement groove 21 (rotation-stop mechanism) that restrict the relative rotation between the shaft 2 and the sleeve 3. Therefore, when attaching or detaching the adapter 1 to or from the electric hammer 50, the shaft 2 can be rotated while holding the sleeve 3, and phase alignment can be easily performed.
The front end of the sleeve 3, into which the rear end 101 of the drift pin 100 is inserted, is formed with a tapered hole 18 having a tapered shape that increases in diameter toward the front. This allows for tolerance of vibration of the adapter 1 during driving, and allows the rear end 101 of the drift pin 100 to be smoothly guided into the sleeve 3.
The stopper 10 and the inner sleeve 19 (stopper mechanism) that restrict the forward movement of the shaft 2 when the driving of the drift pin 100 into the workpiece W is completed are provided so as to be visible. Therefore, the worker can easily confirm the completion of the driving of the drift pin 100.

In the invention relating to the adapter and the electric hammer equipped with the adapter, the anti-rotation mechanism between the shaft and the sleeve may be formed between the shaft and the sleeve without the inner sleeve. For example, it is conceivable to form a key on one of the shaft and the sleeve and a key groove on the other, or to connect them by splines.
The stopper mechanism can also be modified as appropriate. Not only can the shape of the stopper itself be modified, but the position of the stopper can also be changed in the axial direction of the shaft.
In addition, the orientation and arrangement of the motor, the type of motor, the position of the controller, the position and number of the battery packs, etc. may be changed. The impact tool is not limited to a DC tool powered by a battery pack, but may be an AC tool powered by a commercial power source or an air tool. A hammer drill may also be used instead of an electric hammer.

(Effects of the invention relating to an electric hammer using a battery pack)
The electric hammer 50 of the above-mentioned embodiment 1 includes a housing 50a that houses a motor 54 and has a handle portion 58, a battery pack 66 (battery) that is detachable from the housing 50a, and an impact mechanism 53 that is operated by driving the motor 54. The electric hammer 50 also includes an adapter 1 (drift pin driving mechanism) that includes a shaft 2 that is disposed in front of the impact mechanism 53 and to which impact is transmitted by the impact mechanism 53, a sleeve 3 that is exteriorly mounted so as to be movable relatively in the forward and backward directions with respect to the shaft 2 by a predetermined stroke, and into whose front end a rear end 101 of a drift pin 100 can be inserted, and a coil spring 4 that biases the sleeve 3 toward a forward position that is the front end of the stroke.
By using the battery pack 66 as the drive unit in this manner, it is possible to improve the ease of handling and the efficiency of the driving work.

Since the upper part of the handle portion 58 is located on the axis L of the shaft 2 behind the impact mechanism 53, it is easy to press the drift pin 100 and the pressing force from the handle portion 58 can be efficiently transmitted to the drift pin 100.
The system is provided with a sensor 90 and a controller 68 (driving end detection means) for detecting the completion of driving the drift pin 100 into the workpiece W. Therefore, when driving is completed, measures such as stopping the driving of the motor 54 can be quickly taken.
The driving end detection means includes a sensor 90 that measures, in a non-contact manner, the distance between the workpiece W and the housing 50a that advances as the drift pin 100 is driven in. Therefore, even if the driving end detection means is provided, it does not interfere with the work.
When the driving end detection means detects the completion of driving of the drift pin 100, the driving of the motor 54 is stopped. Therefore, after the driving is completed, no impact is applied, which leads to the protection of the workpiece W to be driven.

The housing 50a has a main housing 51 and a motor housing 52 (driving side housing) which include the impact mechanism 53 and the adapter 1, and an outer housing 56 and a handle housing 57 (handle side housing) which are connected to the main housing 51 and the motor housing 52 so as to be movable relatively over a predetermined forward and backward stroke and which include a handle portion 58. First and second coil springs 83, 86 (elastic means) are provided between the main housing 51 and the motor housing 52 and the outer housing 56 and the handle housing 57 for biasing the outer housing 56 and the handle housing 57 to a retracted position which is the rear end of the forward and backward stroke.
Therefore, vibrations generated by the impact mechanism 53 and the adapter 1 are less likely to be transmitted to the handle portion 58, resulting in a comfortable feel when using the tool.

When starting to drive the drift pins 100, the rotation speed of the motor 54 is controlled so as to gradually increase from a low speed at the start of driving. This reduces the impact at the start of driving.
The speed dial 89 and the controller 68 (speed change mechanism) are provided to arbitrarily change the rotation speed of the motor 54. Therefore, the number of strikes that is easy to work with can be selected, and the usability is improved.
The drift pin driving mechanism is a detachable adapter 1. Therefore, maintenance and replacement of the adapter 1 can be easily performed.

In the invention relating to the electric hammer using a battery pack, the end-of-strike detection means is not limited to a non-contact sensor, but may also be a contact type. For example, if a stopper pole that protrudes forward is attached to the housing, the driving is completed when the stopper pole abuts against the surface of the workpiece. It is preferable that the amount of forward protrusion of the stopper pole can be changed.
When the driving is completed, the control is not limited to stopping the driving of the motor, but the rotation speed of the motor may be reduced.
The control of the motor from the start of striking is not limited to a soft start, but may be constant from the beginning, or may be driven at a number of constant speeds that gradually increase in number. The number of rotations may also be increased according to the load on the motor and the vibrations caused by striking.
The control of these motors may be set as driving modes in the controller, and the operator may select the modes via an operation panel or the like.

The speed change mechanism is not limited to one that uses a speed change dial, and may be one that changes speed based on the amount of depression of a switch lever.
The position of the handle portion on the axis of the shaft does not have to be at the upper part of the handle portion.
In addition, the direction and arrangement of the motor, the type of motor, the position of the controller, the position and number of the battery packs, etc. may be changed as appropriate. A hammer drill may be used as the impact tool instead of an electric hammer.

(Explanation of adapter modification examples)
Next, a modified example of the adapter common to each invention will be described.
4 shows a magnet 25 exposed inside the small diameter hole 15 provided at the front end of the sleeve 3 as a holding mechanism for holding the rear end 101 of the drift pin 100. The rear end 101 of the drift pin 100 inserted into the small diameter hole 15 is attracted to the magnet 25, thereby holding the rear end 101.
In this way, by providing the magnet 25 capable of holding the rear end 101 of the inserted drift pin 100 at the front end of the sleeve 3, the drift pin 100 is less likely to fall off the sleeve 3, improving workability.
The shape of the magnet is not limited to this, and may be other shapes such as a ring shape or a C shape, or multiple magnets may be arranged. Also, although the front end of the small diameter hole is not tapered here, it may be tapered as long as it is possible to attract the drift pin.
5 shows the same holding mechanism in which an O-ring 26 is held on the inner circumference of the tip of the small diameter hole 15. This O-ring 26 holds the rear end 101 of the drift pin 100 inserted into the small diameter hole 15. This makes it difficult for the drift pin 100 to fall out of the sleeve 3, improving workability.
The number of O-rings is not limited to one, and multiple O-rings may be arranged in the axial direction. Elastic rings other than O-rings may also be used. A combination with a magnet is also possible.

6, a ring groove 27 is formed on the inner peripheral surface of the tapered portion 17 of the sleeve 3 to hold an O-ring 28 that slides against the front portion 5. Also, a ring groove 29 is formed on the outer peripheral surface of the flange 8 to hold an O-ring 30 that slides against the large diameter hole 16.
The O-rings 28, 30 elastically support the shaft 2 in the radial direction within the sleeve 3. This makes it difficult for the shaft 2 to come into contact with the sleeve 3, thereby reducing the noise generated when the drift pin 100 is driven in.
The number of O-rings is not limited to one, and a plurality of O-rings may be arranged in the axial direction. Elastic rings other than O-rings may also be used.
6, the sleeve 3 is made of resin and the outer periphery of the sleeve 3 is covered with a sound absorbing sponge 31. Therefore, even if the shaft 2 comes into contact with the sleeve 3, the generated sound is reduced, and the generated sound is absorbed and reduced by the sound absorbing sponge 31.

By providing such a sound-deadening mechanism, the sound generated during driving can be effectively reduced. However, it is not necessary to use all of the elastic support of the shaft, the resin molding of the sleeve, and the sound-absorbing sponge at the same time; only one or two of them may be used. Other sound-deadening mechanisms can also be used.

7 shows an example in which a protective portion 32 made of resin or rubber is provided on the front end surface of the sleeve 3. This protective portion 32 can protect the surface of the workpiece W when the sleeve 3 comes into contact with it.
The shape of the protective portion can be changed as appropriate, and may be formed by laminating materials of different types or physical properties in the front-rear direction. Even when the entire sleeve 3 is made of resin as shown in Figure 6, the front end surface serves as the protective portion.

8 and 9 show an example in which the stopper 10A is cylindrical and made up of a rear tube 33 and a front tube 34 that opens forward from the rear tube 33. The rear tube 33 is connected to the rear portion 7 of the shaft 2 by a pin 35. The front tube 34 is fitted from the rear to the rear end of the sleeve 3. A stopper portion 36 is provided on the outer circumferential surface of the sleeve 3, against which the front tube 34 abuts when it advances a distance D1.
The inner sleeve 19 does not have a flange portion, and is entirely press-fitted into the sleeve 3, and both ends of a rotation-prevention pin 37 that penetrates the intermediate portion 6 of the shaft 2 are engaged with a pair of engagement grooves 21, 21. Thus, the rotation of the shaft 2 and the sleeve 3 relative to each other is restricted.
In this case, when the driving of the drift pin 100 is completed, the front tube 34 of the stopper 10A covers the rear end of the sleeve 3 from the outside and abuts against the stopper portion 36, as shown in Figure 10. Therefore, the worker can visually confirm the completion of the driving. At this time, the rear end face of the sleeve 3 abuts against the front face of the rear tube 33 inside the front tube 34.
In this way, the stopper mechanism is a stopper 10A (stopper member) that is attached integrally to the shaft 2 so as to be movable back and forth and that abuts against the rear end of the sleeve 3 when driving is complete, and the stopper 10A is cylindrical so as to cover the outer periphery of the rear end of the sleeve 3 and overlap in the radial direction when driving is complete. This closes the gap between the sleeve 3 and the stopper 10A, reducing the risk of foreign matter such as wood chips entering the adapter 1.

[Form 2]
In the above embodiment, a separate adapter 1 is attached to an existing electric hammer 50, but it can also be an impact tool dedicated to drift pins, with the adapter function integrated into the tip as a driving mechanism. An example of such an impact tool, a drift pin driving machine (hereinafter referred to as a "driving machine"), will be described below. However, the same components as the adapter 1 and electric hammer 50 of embodiment 1 are given the same reference numerals, and duplicated descriptions will be omitted.
(Explanation of the hammering machine)
A driving mechanism 1A is provided at the tip of the driving tool 50A shown in FIG. 11. In the driving mechanism 1A, a shaft 2A is loosely inserted in a front end 95 of a tool holder 70 that is extended forward, as shown in FIG. 12, so as to be movable back and forth. The shaft 2A has a front portion 5 whose front end surface 5a is spherical, and a rear portion 7 having recesses 13. The front end 95 is provided with a pair of engagement pins 96, 96 that are loosely inserted from the outside in the radial direction and whose tips engage with the recesses 13, 13. The outer diameter of the front end 95 gradually increases from the tip to the rear, from a small diameter portion 97 to a medium diameter portion 98 to a large diameter portion 99. The engagement pins 96, 96 are arranged in the medium diameter portion 98.

A sleeve 3A is fitted around the front end 95. The sleeve 3A is provided with a front small diameter hole 40 fitted around the small diameter portion 97 and a rear large diameter hole 41 fitted around the medium diameter portion 98, which are coaxial with each other. A tapered hole portion 18 is formed in front of the small diameter hole 40, the diameter of which increases rearward, and the rear end of the tapered hole portion 18 forms a front stopper 42 having a diameter smaller than that of the small diameter hole 40.
A pair of slits 43, 43 in the front-rear direction that communicate with the large diameter hole 41 are formed in the rear part of the sleeve 3A, and engagement pins 96, 96 are loosely inserted into the slits 43, 43 so as to be relatively movable. An outer sleeve 44 is fitted to the rear part of the sleeve 3A outside the slits 43, 43. The outer sleeve 44 is positioned in the front-rear direction between a flange portion 45 formed at the rear end of the sleeve 3A and a locking ring 46 that is locked to the sleeve 3A. The outer sleeve 44 prevents the engagement pins 96, 96 from falling out radially outward. A ring-shaped rear stopper 47 is formed on the outer circumferential surface of the outer sleeve 44.

The coil spring 4 is fitted around the small diameter portion 97 inside the sleeve 3A, with its front end abutting against the step 48 between the small diameter hole 40 and the large diameter hole 41, and its rear end abutting against the front surface of the medium diameter portion 98. The coil spring 4 biases the sleeve 3A to an advanced position where the engagement pins 96, 96 are located at the rear ends of the slits 43, 43.
The front end of the main body housing 51 of the driving tool 50A is a cylindrical portion 93 that fits over the flange portion 45 when the sleeve 3A is in the forward position.
When the sleeve 3A is in the advanced position, the axial distance D1 between the front end face of the cylindrical portion 93 and the rear end face of the rear stopper 47 of the outer sleeve 44 is equal to the axial distance D2 between the front end face of the small diameter portion 97 and the rear end face of the front stopper 42. Distance D1 is also equal to the axial distance D3 between the front end face of the large diameter portion 99 and the rear end face of the flange portion 45 of the sleeve 3A.

(Drift pin insertion)
In the driving tool 50A configured as described above, the handle portion 58 is gripped, and the tapered hole portion 18 of the sleeve 3A is placed over the rear end 101 of the drift pin 100, the front end of which is shallowly inserted into the driving position of the workpiece W, as shown in Figures 11 and 12. Then, the rear end 101 of the drift pin 100 is accommodated in the tapered hole portion 18 and abuts against the front end surface 5a of the shaft 2A, and the shaft 2A is aligned in a substantially straight line with the drift pin 100. When the driving tool 50A is pushed forward with the hand gripping the handle portion 58, the shaft 2A moves relatively backward within the tool holder 70, as shown in Figure 13, and the engaging pins 96, 96 are engaged with the front ends of the recesses 13, 13, and the rear portion 7 abuts against the impact bolt 80. Next, the outer housing 56 and the handle housing 57 move forward against the urging forces of the first and second coil springs 83, 86.
When the switch lever 63 is pressed to turn the switch 62 ON, the controller 68 drives the motor 54. Again, the controller 68 executes a soft start and then drives the motor 54 at the set rotation speed.

When the output shaft 55 of the motor 54 rotates, the crankshaft 72 rotates via the pinion 75 and the gear 74. Thus, the piston 76 moves back and forth via the connecting rod 77. This causes the striker 79 to move back and forth in tandem via the air chamber 78. The striker 79 indirectly strikes the shaft 2A via the impact bolt 80, so that the drift pin 100 is driven into the workpiece W. At this time, the spherical front end surface 5a of the shaft 2A abuts against the rear end 101 of the drift pin 100, so that the strike is always transmitted to the axis of the drift pin 100. In addition, the hand holding the handle portion 58 is located rearward on the axis L of the shaft 2A (axis L of the tool holder 70), so that the forward pressing force by the operator is transmitted to the shaft 2 without loss.
During operation, the outer housing 56 and the handle housing 57 advance against the biasing forces of the first and second coil springs 83, 86 and are not in contact with the main housing 51 and the motor housing 52. This suppresses vibrations transmitted to the first and outer housings 56 and the handle housing 57 during driving, and reduces vibrations transmitted to the hand holding the handle portion 58.

As the driving proceeds, the driving machine 50A advances and the front end of the sleeve 3A abuts against the surface of the material W to be driven. Then, the sleeve 3A remains as it is and the shaft 2A advances while continuing the driving. Therefore, as shown in FIG. 14, the cylindrical portion 93 abuts against the rear stopper 47 of the outer sleeve 44 and the large diameter portion 99 abuts against the flange portion 45. At this time, the small diameter portion 97 also abuts against the front stopper 42, and the front end surface 5a is in the same front-to-rear position as the front end surface of the sleeve 3A. In this way, the rear end surface of the drift pin 100 becomes flush with the surface of the material W to be driven, and the drift pin 100 is completely driven into the material W to be driven. Therefore, if the operator visually confirms that the cylindrical portion 93 abuts against the rear stopper 47 of the outer sleeve 44 and releases the driving machine 50A, the driving operation is completed. The controller 68 monitors the measurement signal from the sensor 90, and when it determines that the distance to the workpiece W reaches the driving completion distance of the drift pin 100, it stops driving the motor 54.
During the driving operation, the worker supports the sleeve 3A with the other hand, but since the coil spring 4 is inside the sleeve 3A and the sleeve 3A is almost entirely exposed, the worker can easily grasp and support the sleeve 3A. In addition, there is less risk of foreign matter such as wood chips generated from the material W being driven in getting inside.

(Effects of the invention relating to the driving machine)
The driving machine 50A of the above-mentioned second embodiment includes a shaft 2A capable of striking the drift pin 100, a sleeve 3A that is mounted on the shaft 2A so as to be movable in the front-rear direction relative to the shaft 2A by a predetermined stroke and into whose front end the rear end 101 of the drift pin 100 can be inserted, and a coil spring 4 that biases the sleeve 3A to a forward position that is the front end of the stroke, and the coil spring 4 has at its tip a driving mechanism 1A (drift pin driving mechanism) that is disposed inside the sleeve 3A. The driving machine 50A also includes a striking mechanism 53 capable of striking the rear end of the shaft 2A, and a motor 54 (drive unit) that operates the striking mechanism 53.
This configuration maintains good operability and durability without foreign matter getting caught and interfering with the relative movement of the sleeve 3A, or without external impact damaging the coil spring 4. In addition, since the sleeve 3A can be securely gripped, the device is easy to use.

The driving machine 50A further comprises a housing 50a which houses the motor 54 and has a handle portion 58, a battery pack 66 (battery) which is detachable from the housing 50a, and an impact mechanism 53 which is actuated by the driving of the motor 54. The driving machine 50A further comprises a driving mechanism 1A (drift pin driving mechanism) which includes a shaft 2A which is disposed in front of the impact mechanism 53 and to which impact is transmitted by the impact mechanism 53, a sleeve 3A which is exterior-mounted so as to be movable relatively in the front-rear direction by a predetermined stroke relative to the shaft 2A and into whose front end the rear end 101 of the drift pin 100 can be inserted, and a coil spring 4 which biases the sleeve 3A to an advanced position which is the front end of the stroke.
By using the battery pack 66 as the drive unit in this manner, it is possible to improve the ease of handling and the efficiency of the driving work.

The cylindrical portion 93 and the rear stopper 47 (stopper mechanism) that restrict the forward movement of the shaft 2A when the driving of the drift pin 100 is completed are provided so as to be visible, so that the worker can easily confirm that the driving of the drift pin 100 is completed.
The stopper mechanism is a main housing 51 (stopper member) that is attached integrally to the shaft 2A so as to be movable back and forth and that abuts against the outer sleeve 44 of the sleeve 3A when driving is completed, and the front end of the main housing 51 is a cylindrical portion 93 that radially overlaps with the rear end of the sleeve 3A. This blocks the space between the sleeve 3A and the cylindrical portion 93, reducing the risk of foreign matter such as wood chips entering the driving mechanism 1A.
In addition, the same effects can be obtained in the second embodiment with respect to the same components as in the first embodiment.

In the second embodiment, a mechanism for holding the drift pin may be formed by providing a magnet, an O-ring, or the like at the front end of the sleeve, as in the first embodiment. The shaft may be elastically supported in the radial direction within the sleeve.
As a sound-deadening mechanism, the sleeve can be made of resin, and the outer periphery can be covered with sound-absorbing sponge. It is also possible to provide a protective part at the front end of the sleeve to protect the surface of the material being driven.
In addition, the structure of the driving machine other than the driving mechanism may be modified in the same manner as the electric hammer of form 1. The orientation and arrangement of the motor, the type of motor, the position of the controller, the position and number of battery packs, etc. may also be modified.

1: Drift pin driving adapter, 1A: Driving mechanism, 2, 2A: Shaft, 3, 3A: Sleeve, 4: Coil spring, 5: Front part, 5a: Front end face, 6: Middle part, 7: Rear part, 8: Flange, 9, 37: Anti-rotation pin, 10: Stopper, 13: Recess, 14: Small diameter hole, 15: Large diameter hole, 18: Tapered hole part, 19: Inner sleeve, 20, 45: Flange part, 21: Engagement groove, 25: Magnet, 26, 28, 30: O-ring, 31: Sound absorbing sponge, 32: Protective part, 33: Rear cylinder, 34: Front cylinder, 36: Stopper part, 40: Small diameter hole, 41: Large diameter hole, 42: Front stopper, 4 3: Slit, 44: Outer sleeve, 47: Rear stopper, 50: Electric hammer, 50a: Housing, 50A: Drift pin driver, 51: Main body housing, 52: Motor housing, 53: Impact mechanism, 54: Motor, 55: Output shaft, 56: Outer housing, 57: Handle housing, 58: Handle, 62: Switch, 63: Switch lever, 68: Controller, 70: Tool holder, 83: First coil spring, 86: Second coil spring, 89: Speed change dial, 90: Sensor, 95: Front end, 100: Drift pin, 101: Rear end, L: Shaft axis.

Claims (10)

a housing that houses a motor and has a handle portion;
a battery detachable from the housing;
An impact mechanism that is driven by the motor;
a drift pin driving mechanism including: a shaft disposed in front of the impact mechanism and to which impact is transmitted by the impact mechanism; a sleeve mounted on the shaft so as to be movable relative to the shaft in the forward and backward directions by a predetermined stroke, the sleeve having a front end into which a rear end of a drift pin can be inserted; and a coil spring that biases the sleeve toward a forward position which is the front end of the stroke;
Equipped with
The housing has a drive side housing which includes the impact mechanism and the drift pin driving mechanism, and a handle side housing which is connected to the drive side housing so as to be able to move relatively over a predetermined forward and backward stroke and which includes the handle portion, and an elastic means is provided between the drive side housing and the handle side housing for urging the handle side housing to a retracted position which is the rear end of the forward and backward stroke . The impact tool according to claim 1, characterized in that at least a portion of the handle portion is located on the axis of the shaft behind the impact mechanism. The impact tool according to claim 1 or 2, characterized in that it is provided with a driving end detection means for detecting the completion of driving the drift pin into the workpiece. The impact tool according to claim 3, characterized in that the driving end detection means includes a sensor that non-contact measures the distance between the driven material and the housing that advances as the drift pin is driven in. The impact tool according to claim 3 or 4, characterized in that the motor stops driving when the driving end detection means detects that the driving of the drift pin has been completed. 6. The impact tool according to claim 1 , wherein when driving in the drift pin is started, the rotation speed of the motor starts from a low state and gradually increases. 6. The impact tool according to claim 1 , wherein the motor is driven at a rotational speed including a plurality of constant rotational speed states which are gradually increased. 8. The impact tool according to claim 1, further comprising a speed change mechanism capable of arbitrarily changing a rotation speed of the motor. 9. The impact tool according to claim 1, wherein the drift pin driving mechanism is a detachable adapter. 10. The impact tool according to claim 1 , wherein the shaft is elastically supported in the radial direction within the sleeve .

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