Patent Grant
10513022
The present invention relates to an impact tool for performing an operation on a workpiece.
WO2007/039356 discloses an electric machine tool in which a housing shell half with a handgrip to be held by user and a housing shell half having a striking mechanism housed therein are separately arranged from each other. The two housing shell halves form an outer shell of the electric machine tool and are connected to each other via a compression spring, so that the shell halves can move with respect to each other.
Patent Document 1: WO2007/039356
The above-described electric machine tool is capable of absorbing vibration of the housing having the striking mechanism housed therein, so that transmission of vibration to a user's hand is reduced. However, the striking mechanism itself is not vibration-proof, so that the striking output may be adversely affected by vibration caused from the striking mechanism. Therefore, it is desired to provide a vibration-proofing structure to reduce or minimize transmission of vibration from the striking mechanism to the user and to reduce influence on the striking output.
Accordingly, it is an object of the present invention to provide a technique for reducing or minimizing transmission of vibration caused by hammering operation to a user while enhancing striking output efficiency.
In order to solve the above-described problem, according to the present invention, an impact tool is configured to perform a hammering operation on a workpiece by driving a tool accessory in a prescribed longitudinal direction. The impact tool has a body and a striking mechanism that drives the tool accessory in the longitudinal direction. The longitudinal direction in which the tool accessory is driven coincides with an axial direction of the tool accessory when the tool accessory is attached to the impact tool. The striking mechanism does not include all mechanisms required for driving the tool accessory in the longitudinal direction, but it is sufficient to include only some of the mechanisms.
The body has a first body element and a second body element. The striking mechanism is provided on the first body element, and the first body element is configured to be movable with respect to the second body element. In this case, for example, a driving motor and a handgrip to be held by a user may be provided on the second body element.
Further, the first body element and the second body element are connected via a cushioning mechanism, and a vibration reducing mechanism is provided on the first body element.
In the impact tool according to this aspect of the present invention, vibration caused by the striking mechanism is efficiently reduced by the first body element. Therefore, adverse effect of vibration caused by impact driving on the striking force is reduced.
Further, with the structure in which the first body element having the striking mechanism mounted thereto and the second body element are connected via the cushioning mechanism, vibration caused by impact driving is not easily transmitted to the second body element. In this case, for example, in a structure in which a handgrip as described below is provided on the second body element, transmission of vibration to a user's hand is reduced.
According to a further aspect of the impact tool of the present invention, the vibration reducing mechanism may be a counter weight. In this case, the counter weight may include a weight part provided on the first body element.
According to a further aspect of the impact tool of the present invention, the vibration reducing mechanism may be a dynamic vibration reducer. In this case, the dynamic vibration reducer includes an elastic member having a first elastic member disposed on the first body element side and a second elastic member disposed on the second body element side, and a weight part disposed between the first elastic member and the second elastic member.
In the impact tool according to this aspect, vibration caused by impact driving is efficiently reduced by reciprocating movement of the weight part between the first elastic member and the second elastic member.
According to a further aspect of the impact tool of the present invention, the impact tool may have a driving motor that is provided on the second body element and drives the striking mechanism. In this case, transmission of vibration from the striking mechanism to the driving motor is reduced.
According to a further aspect of the impact tool of the present invention, the impact tool may have a handgrip designed to be held by a user and having an extending axis that extends in a direction crossing a central axis of the tool accessory extending in the longitudinal direction. An operation part such as a trigger may be arranged on the handgrip and operated by a user to energize the driving motor. In such a structure, the center of gravity of the weight part may be located on a plane defined by the central axis and the extending axis.
In the impact tool according to this aspect, the vibration reducing mechanism stably reduces vibration caused by driving of the striking mechanism.
Further, in the impact tool according to this aspect, the impact tool may be configured to have its center of gravity on the above-described central plane. In this case, the center of gravity of the impact tool and the center of gravity of the weight part are located on the same plane. Therefore, the user can hold the impact tool with stability,
According to a further aspect of the impact tool of the present invention, the weight part may include a plurality of weight elements. Specifically, the number of the weight elements may be freely determined in consideration of requirements for the impact tool to be designed.
According to a further aspect of the impact tool of the present invention, the first body element and the second body element may be connected via a guide part. In this case, the weight part and the elastic member may be arranged coaxially with the guide part and configured to reciprocatingly slide with respect to the guide part.
In the impact tool according to this aspect, the weight part smoothly slides on the guide part, so that the vibration reducing effect of the vibration reducing mechanism is enhanced.
Further, in the impact tool according to this aspect, the extending direction of the guide part may be parallel to the longitudinal direction. In this case, the weight part reciprocates in the longitudinal direction, so that the vibration reducing mechanism can achieve more efficient vibration reduction.
According to the present invention, an impact tool is provided that reduces or minimizes transmission of vibration caused by hammering operation to a user while enhancing striking output efficiency.
An impact tool according to the present invention is now summarized with reference to
The body 101 has a first body element 101a and a second body element 101b. The striking mechanism 140 is provided on the first body element 101a, and the first body element 101a is configured to be movable with respect to the second body element 101b. When the impact tool 100 is not pressed against a workpiece by a user (in a non-pressed state), the first body element 101a and the striking mechanism 140 are biased to the tip side (forward). When the user holds the handgrip 109 and presses the tip of the tool accessory 119 against the workpiece, the tool accessory 119 is moved in a direction of an arrow 119d. By movement of the tool accessory 119 in the direction of the arrow 119d, the first body element 101a and the striking mechanism 140 are moved in a direction of an arrow 101ad. The directions of the arrows 119d, 101ad are opposite to a direction toward the tip side (forward direction) and thus referred to as an opposite (rearward) direction. In this sense, the tool accessory 119, the striking mechanism 140 and the first body element 101a are integrated together and can move together with respect to the second body element 101b.
The first body element 101a is configured to be movable with respect to the second body element 101b. In other words, the first body element 101a and the second body element 101b can move with respect to each other. The second body element 101b refers to a prescribed region of the body 101 which can move with respect to the first body element 101a. In this case, for example, a part connected to the first body element 101a may form the second body element 101b. When the second body element 101b is configured as the prescribed region of the body 101, the electric motor 110 may be mounted to the second body element 101b and the handgrip 109 may be provided on the second body element 101b. In this sense, it can be said that the first body element 101a and the electric motor 110 can move with respect to each other, and that the first body element 101a and the handgrip 109 can move with respect to each other.
Further, the body 101 of the impact tool 100 may be configured, for example, such that a region having the electric motor 110 and a region having the handgrip 109 are separated from each other and a prescribed region of the body 101 having the electric motor 110 and a prescribed region of the body 101 having the handgrip 109 can move with respect to each other. In this case, the two prescribed regions of the body 101 may be connected via a vibration proofing mechanism such as a dynamic vibration reducer.
In this case, a plurality of such second body elements 101b which can move with respect to the first body element 101a may be provided, and the present invention also includes such configuration.
The first body element 101a and the second body element 101b are connected via a cushioning mechanism 300. The cushioning mechanism 300 may include an elastic element such as a coil spring and rubber. The cushioning mechanism 300 biases the first body element 101a forward.
A vibration reducing mechanism 200 is further provided on the first body element 101a. In
Each of the vibration reducing mechanism 200 and the cushioning mechanism 300 has an extending axis. The striking mechanism 140 has an extending axis extending in the axial direction of the tool accessory 119. It is preferred that the extending axis of the vibration reducing mechanism 200 is arranged closer to the extending axis of the striking mechanism 140 than to the extending axis of the cushioning mechanism 300. Further, it is preferred that the extending axis of the vibration reducing mechanism 200 extends in parallel to the extending axis of the striking mechanism 140. It is further preferred that the extending axes of the vibration reducing mechanism 200, the striking mechanism 140 and the cushioning mechanism 300 are parallel to each other.
In the impact tool 100 having such a structure, the vibration reducing mechanism 200 reduces vibration caused by driving of the striking mechanism 140. As a result, the striking mechanism 140 is driven with stability. Further, the vibration reduced by the vibration reducing mechanism 200 is transmitted to the second body element 101b via the cushioning mechanism 300. Therefore, transmission of vibration to the user is reduced. At this time, the electric motor 110, which is provided in the second body element 101b, is less adversely affected by the vibration.
A first embodiment of the present invention is now explained with reference to
(Basic Structure Relating to the Outer Appearance)
Referring to an external view shown in
As shown in
The axial direction in which the hammer drill 100 drives the hammer bit 119 defines the longitudinal direction of the hammer drill 100. The longitudinal direction coincides with the axial direction of the hammer bit 119 when the hammer bit 119 is attached to the hammer drill 100. The hammer bit 119 is attached to a front end region of a tool holder 159, which will be described below in further detail with reference to
As shown in
The central axis 100a, the extending axis 100b and the central plane 100c are example embodiments that correspond to the “central axis”, the “extending axis” and the “prescribed plane”, respectively, according to the present invention.
The hammer drill 100 has prescribed drive modes, i.e. a hammer mode of causing the hammer bit 119 to perform hammering motion in the axial direction of the hammer bit 119, a drill mode of causing the hammer bit 119 to perform rotating motion around the axis of the hammer bit 119, and a hammer drill mode of causing the hammer bit 119 to perform hammering motion in the axial direction and rotating motion around the axis. The drive modes can be switched with a changeover dial 165. In the following description, for the convenience sake, a structure of biasing the hammer bit 109 toward a prescribed position and a structure of switching the drive mode with the changeover dial 165 may be omitted except for a structure pertaining to the present invention.
(Structure of the Body Housing)
As shown in
The body housing 101 mainly includes a motor housing 103 and a gear housing 105. The motor housing 103 is arranged in a rear region of the body housing 101, and the gear housing 105 is arranged in a front region of the body housing 101. Further, the handgrip 109 is arranged on the lower side of the motor housing 103. The motor housing 103 and the gear housing 105 are fixedly connected to each other by a fastening means such as screws so as not to move with respect to each other. Thus, the single body housing 101 is formed. Specifically, the motor housing 103 and the gear housing 105 are formed as separate housings in which respective internal mechanisms are mounted, and integrally connected together by the fastening means to form the single body housing 101.
(Structure of the Motor Housing) As shown in
Specifically, the electric motor 110 is mounted to the motor housing 103 via a baffle plate 103b by fastening means such as screws 103a. The electric motor 110 is housed in the motor housing 103 such that an extending axis of an output shaft 111 of the electric motor 110 extends in parallel to the axis of the hammer bit 119. The output shaft 111 protrudes forward through the baffle plate 103b, and a motor cooling fan 112 is mounted to a front end region of the output shaft 111 and rotates together with the output shaft 111. A pinion gear 113 is provided in front of the fan 112 on the output shaft 111. A front bearing 114 is provided between the pinion gear 113 and the fan 112, and a rear bearing 115 is provided on a rear end of the output shaft 111. With such a structure, the output shaft 111 is rotatably supported by the bearings 114, 115. Further, the front bearing 114 is held by a bearing support part 107 which forms part of the gear housing 105, and the rear bearing 115 is held by the motor housing 103. Therefore, the electric motor 110 is held such that the pinion gear 113 protrudes into the gear housing 105. Further, the pinion gear 113 is typically formed as a helical gear. The electric motor 110 is an example embodiment that corresponds to the “driving motor” according to the present invention.
The bearing support part 107 is fixed to the motor housing 103 and the gear housing 105, so that the bearing support part 107 cannot move with respect to the motor housing 103 and the gear housing 105.
A holding member 130 to which the striking mechanism 140 is mounted is movably connected to the bearing support part 107 as described below. The holding member 130 and the bearing support part 107 are example embodiments that correspond to the “first body element (first body element 101a according to
(Structure of the Gear Housing)
As shown in
The bearing support part 107 and the guide support part 108 are fixedly mounted to an inner peripheral surface of the housing part 106. The bearing support part 107 supports the bearing 114 for holding the output shaft 111 of the electric motor 110 and a bearing 118b for holding an intermediate shaft 116. The guide support part 108 is disposed substantially in a middle region of the gear housing 105 in the longitudinal direction of the hammer drill 100 and supports front end parts of a first guide shaft 170a and a second guide shaft 170b (see
As shown in
The intermediate shaft 116 is mounted in the gear housing 105 and rotationally driven by the electric motor 110. The intermediate shaft 116 is rotatably supported with respect to the gear housing 105 via a front bearing 118a mounted to the gear housing 105 and a rear bearing 118b mounted to the bearing support part 107. Further, the intermediate shaft 116 cannot move in an axial direction of the intermediate shaft 116 (the longitudinal direction of the hammer drill 100) with respect to the gear housing 105. The clutch mechanism 180 is provided on a rear end part of the intermediate shaft 116. A driven gear 117 which engages with the pinion gear 113 of the electric motor 110 is fitted on the clutch mechanism 180. Like the pinion gear 113, the driven gear 117 is also formed as a helical gear. With such a structure, the intermediate shaft 116 is rotationally driven by the output shaft 111 of the electric motor 110. By forming the driven gear 117 and the pinion gear 113 as helical gears, noise caused in rotation transmission between the pinion gear 113 and the driven gear 117 is suppressed.
(Structure of the Striking Mechanism Part]
As shown in
As shown in
As shown in
As shown in
As shown in
Further, the “striking mechanism” according to the present invention is described above as the “striking mechanism 140” according to this embodiment, but it may be a structure having the rotary body 123, the swinging shaft 125, the joint pin 126, the connecting element 126a and the piston 127 in addition to the striking mechanism 140.
As shown in
When the piston 127 is moved in the back-and-forth direction by swinging movement of the swinging shaft 125, air pressure of the air chamber 127a fluctuates, so that the striker 143 slides in the longitudinal direction of the hammer drill 100 within the piston 127 by the action of the air spring. When the striker 143 is moved forward, the striker 143 collides with the impact bolt 145 and the impact bolt 145 collides with the hammer bit 119 held by the tool holder 159. As a result, the hammer bit 119 is moved forward and performs a hammering operation on the workpiece.
As shown in
(Relationship between the Striking Mechanism Part, the Vibration Reducing Mechanism and the Cushioning Mechanism)
The relationship between the striking mechanism part, the vibration reducing mechanism 200 and the cushioning mechanism 300 are explained with reference to
The above-described striking mechanism assembly is movably held in the longitudinal direction of the hammer drill 100 (the axial direction of the hammer bit 119) with respect to the gear housing 105. Specifically, as shown in
As shown in
Further, the first guide shaft 170a is inserted through a guide insert hole 132a formed in the cylinder holding part 132 of the holding member 130. The vibration reducing mechanism 200 is disposed between the cylinder holding part 132 and the bearing support part 107.
The vibration reducing mechanism 200 of the hammer drill 100 according to the first embodiment is configured as a dynamic vibration reducer having a weight part 220 and an elastic member 210. The elastic member 210 includes a first elastic member 210a disposed on the cylinder holding part 132 side and a second elastic member 210b disposed on the bearing support part 107 side. The weight part 220 is disposed between the first elastic member 210a and the second elastic member 210b. Specifically, the elastic member 210 (the first elastic member 210a, the second elastic member 210b) and the weight part 220 are arranged coaxially with the first guide shaft 170a and configured to reciprocatingly slide with respect to the first guide shaft 170a. The vibration reducing mechanism 200, the first guide shaft 170a, the first elastic member 210a, the second elastic member 210b and the weight part 220 are example embodiments that correspond to the “vibration reducing mechanism”, the “guide part”, the “first elastic member”, the “second elastic member” and the “weight part”, respectively, according to the present invention.
A weight element having a prescribed weight and shape forms the weight part 220. In the vibration reducing mechanism 200 according to the first embodiment, the weight element is arranged on each of a pair of the first guide shafts 170a. Specifically, the weight part 220 is formed by providing two weight elements. The number of the weight elements is determined by the structure of the hammer drill 100 to be obtained. Specifically, one or more weight elements may be provided. Particularly, a plurality of weight elements may be provided on a single first guide shaft 170a. Further, two or more first guide shafts 170a may be provided, and the weight element and the elastic member 210 may be provided on each of the first guide shafts 170a.
When the hammer drill 100 is viewed from the front with respect to the central plane 100c, the extending axis of the striking mechanism 140 and the extending axis of the vibration reducing mechanism 200 have regions overlapping each other. Here, the hammer drill 100 viewed from the front with respect to the central plane 100c represents the hammer drill 100 viewed from a direction perpendicular to the longitudinal direction of the hammer drill 100, for example, as shown in
Further, the hammer drill 100 may be configured to have its center of gravity on the central plane 100c. In this case, the center of gravity of the hammer drill 100 and the center of gravity of the weight part 220 are located on the same plane. Therefore, the user can hold the hammer drill 100 with stability, resulting in that the vibration reducing mechanism 200 can achieve a further higher vibration reducing effect.
As shown in
Further, the second guide shaft 170b is supported through the rotary body holding part 131. Specifically, the rotary body holding part 131 has a front part 131a, a rear part 131c and an intermediate part 131b extending between the front part 131a and the rear part 131c. In the front part 131a, the second guide shaft 170b is inserted through a guide insert hole 131a1 via a bearing 170b1. In the rear part 131b, the second guide shaft 170b is inserted through a guide insert hole 131c1 via a bearing 170b2.
A second cushioning elastic member 302 is disposed coaxially with the second guide shaft 170b between the rear part 131c and the bearing support part 107. A first cushioning elastic member 301 is disposed between the connecting element 126a fixed to the piston 127 and the bearing support part 107. The first and second cushioning elastic members 301, 302 are coil springs and form the cushioning mechanism 300 described above with reference to
The holding member 130 and the striking mechanism part (the motion converting mechanism 120, the striking mechanism 140 and the tool holder 159) are biased forward by the cushioning mechanism 300. At this time, as shown in
(Structure of the Clutch Mechanism)
The above-described striking mechanism part is driven by the electric motor 110 via the clutch mechanism 180. The clutch mechanism 180 is configured to be switched between a power transmission state and a power non-transmission state. Therefore, when the clutch mechanism 180 is in the power transmission state, the motion converting mechanism 120 is driven and the striking mechanism 140 strikes the hammer bit 119, so that hammering operation is performed. The clutch mechanism 180 is not further elaborated here for convenience of explanation of the present invention.
(Structure of the Rotation Transmitting Mechanism)
As shown in
As shown in
The second gear 153 is configured to move in the axial direction of the first gear 151 with respect to the first gear 151 when the cylinder 129 (the tool holder 159) moves in the back-and-forth direction, while being always held in engagement with the first gear 151.
When the first gear 151 is rotationally driven, the second gear 153 engaged with the first gear 151 is rotated. Thus, the tool holder 159 connected to the cylinder 129 is rotationally driven and the hammer bit 119 held by the tool holder 159 is rotationally driven around its axis, so that the hammer bit 119 performs a drilling operation on the workpiece.
(Operation of the Hammer Drill)
By user's operation of the changeover dial 165 shown in
Specifically, the changeover dial 165 can be switched to select a state in which the first gear 151 is placed in the rear position and the holding member 130 is allowed to move rearward. In this case, hammer drill mode is selected as the drive mode, and the rotation transmitting mechanism 150 and the striking mechanism part can be driven.
Further, the changeover dial 165 can also be switched to select a state in which the first gear 151 is placed in the front position and the holding member 130 is allowed to move rearward. In this case, hammer mode is selected as the drive mode, and the striking mechanism part can be driven while the rotation transmitting mechanism 150 is not driven.
Furthermore, the changeover dial 165 can also be switched to select a state in which the first gear 151 is placed in the rear position and the holding member 130 is prevented from moving rearward. In this case, drill mode is selected as the drive mode, and the rotation transmitting mechanism 150 can be driven while the striking mechanism part is not driven.
The state in the hammer drill mode or the hammer mode is described with reference to
When a user presses the hammer bit 119 against a workpiece, the motion converting mechanism 120, the striking mechanism 140 and the tool holder 159 (the striking mechanism assembly) which are integrally connected together via the holding member 130 are moved rearward against biasing forces of the first and second cushioning elastic members 301, 302 of the cushioning mechanism 300. In this state, when the user operates the trigger 109a, the hammer bit 119 is impact driven.
In this state, vibration caused by the striking mechanism 140 is absorbed by the vibration reducing mechanism 200 and the cushioning mechanism 300. Particularly, the vibration reducing mechanism 200 in the form of the dynamic vibration reducer efficiently reduces vibration caused by driving of the striking mechanism 140 by reciprocating movement of the weight part 220 between the first elastic member 210a and the second elastic member 210b. As a result, vibration received by the striking mechanism 140 is reduced, so that reduction of the striking force of the striking mechanism 140 is suppressed. Further, transmission of vibration to the handgrip 109 via the bearing support part 107 is also reduced by the vibration reducing mechanism 200 and the cushioning mechanism 300. Therefore, transmission of vibration to the user is reduced.
A hammer drill 100 according to a second embodiment of the present invention is now explained with reference to
In the hammer drill 100 according to the second embodiment, the weight part 220 consisting of a single weight element can be more easily mounted to the first guide shafts 170a.
In the above-described embodiments, the handgrip 109 is formed in a cantilever form extending downward from the motor housing 103, but the form of the handgrip 109 should not be construed in a limiting sense. For example, the handgrip 109 may be formed in a loop shape such that the distal end of the handgrip 109 is further connected to the motor housing 103.
In the above-described embodiments, the output shaft 111 of the electric motor 110 is arranged to extend in parallel to the axis of the hammer bit 119, but the arrangement of the output shaft 111 should not be construed in a limiting sense. For example, the output shaft 111 of the electric motor 110 may be arranged to cross the axis of the hammer bit 119. In this case, it is preferred that the output shaft 111 and the intermediate shaft 116 are engaged with each other via a bevel gear. Further, it is preferred that the output shaft 111 is arranged perpendicularly to the axis of the hammer bit 119.
In the above-described embodiments, the pinion gear 113 and the driven gear 117 are formed as a helical gear, but the gear should not be construed in a limiting sense. For example, a gear such as a spur gear and a bevel gear may be used.
In view of the nature of the above-described invention, the impact tool according to this invention can be provided with the following features. Each of the features can be used separately or in combination with the other, or in combination with the claimed invention.
(Aspect 1)
An extending axis of the vibration reducing mechanism is arranged closer to an extending axis of the striking mechanism than to an extending axis of the cushioning mechanism.
(Aspect 2)
The extending axis of the vibration reducing mechanism extends in parallel to the extending axis of the striking mechanism.
An impact tool according to a third embodiment of the present invention is now summarized with reference to
In the longitudinal direction, the front side of the tool holder 159 is defined as a front side and the opposite side is defined as a rear side. In this definition, the left and right sides in
The tool holder 159 has a cylindrical hollow structure having a front open end 1591, a rear open end 1592 and an inner peripheral part 1593. The tool accessory 119 can be removably coupled to the inner peripheral part 1593 through the front open end 1591.
The tool holder 159 is press-fitted into the housing cylinder 129 from the rear open end 1292 toward the front open end 1291 up to a prescribed position in the housing cylinder 129. At this time, the tool holder 159 inserted into the housing cylinder 129 from the rear open end 1292 can be press-fitted to the prescribed position in the housing cylinder 129 simply by moving the tool holder 159 toward the front open end 1291 of the housing cylinder 129. As a result, the tool holder 159 and the housing cylinder 129 are integrated together. This means that the positional relation between the tool holder 159 and the housing cylinder 129 is fixed even during hammering operation of the impact tool 100 so as not to cause any trouble in the hammering operation. Even if the positional relation between the tool holder 159 and the housing cylinder 129 varies within a range that causes no trouble in the hammering operation, the tool holder 159 and the housing cylinder 129 are construed as being “integrated together” according to this invention.
In regions of an inner peripheral surface of the housing cylinder 129 and an outer peripheral surface of the tool holder 159 which come in contact with each other by press fitting, any other structure which may become resistance to the press fitting operation is not formed. Specifically, in these regions, a structure protruding from the inner peripheral surface of the housing cylinder 129 or a structure protruding from the outer peripheral surface of the tool holder 159 is not formed. In this sense, it can be said that these regions of the inner peripheral surface of the housing cylinder 129 and the outer peripheral surface of the tool holder 159 form a smooth region, and further the smooth region can also be referred to as an obstacle-free region.
Further, a structure which does not become resistance to the press fitting operation may be formed in the smooth region (obstacle-free region). For example, a recess may be formed in the inner peripheral surface of the housing cylinder 129 or the outer peripheral surface of the tool holder 159. Further, any other structure may be formed in such a recess. In this case, the “other structure” needs to be configured not to become substantial resistance to the press fitting operation
A preventing mechanism 400 is provided to prevent the tool holder 159 from further moving forward when the tool holder 159 and the housing cylinder 129 are integrated together.
The preventing mechanism 400 includes a restriction part 410 on the tool holder 159 and a stop part 420 on the housing cylinder 129. When the tool holder 159 and the housing cylinder 129 are integrated together, the restriction part 410 comes in contact with the stop part 420 and prevents further movement of the tool holder 159. Specifically, when the tool holder 159 is press-fitted into the housing cylinder 129, the preventing mechanism 400 stops further movement of the tool holder 159. In this sense, the preventing mechanism 400 can be an index part for indicating that the tool holder 159 is press-fitted in up to the prescribed position of the housing cylinder 129.
Further, it may also be configured such that the restriction part 410 is not held in contact with the stop part 420 at the prescribed position if the tool holder 159 and the housing cylinder 129 are held “integrated together”.
In the impact tool 100 having the above-described structure, the tool holder 159 and the housing cylinder 129 are held integrated together during hammering operation, so that the operation can be smoothly performed.
In order to separate the tool holder 159 and the housing cylinder 129, for example, for repair when necessary, the press-fitted state of the tool holder 159 to the housing cylinder 129 can be released. Specifically, the tool holder 159 can be moved toward the rear open end 1292 of the housing cylinder 129 by application of a prescribed pressure to the front of the tool holder 159 in a direction from the front open end 1291 toward the rear open end 1292 of the housing cylinder 129. By further moving the tool holder 159 in this manner, the tool holder 159 can be removed through the rear open end 1292 of the housing cylinder 129. The housing cylinder 129 and the tool holder 159 separated from each other can be reused. Specifically, the housing cylinder 129 and the tool holder 159 can be integrated together again.
A hammer drill 100 according to a fourth embodiment of the present invention is now explained with reference to
Specifically, the stop part 420 of the cylinder 129 is a ring spring 1297. A circumferential groove is formed in the inner peripheral region of the cylinder 129 close to the front open end 1291, and the ring spring 1297 is fitted in the circumferential groove. The ring spring 1297 which forms the preventing mechanism 400 is a separate part from the cylinder 129 and the tool holder 159. Therefore, the ring spring 1297 can be referred to as a fixed member 420a in the preventing mechanism 400. The fixed member 420a is an example embodiment that corresponds to the “fixed member” according to the present invention. Further, the restriction part 410 of the tool holder 159 is formed by forming a wall surface 1598 on a small-diameter part 1594.
As described above, the restriction part 410 can be formed by extending part of the tool holder 159. Specifically, the tool holder 159 can have a prescribed first region 410b in its outer periphery and a second region 410c protruding from the first region 410b in a direction crossing the longitudinal direction of the hammer drill. In such a structure, the second region 410c can form the restriction part 410. In the hammer drill of the fourth embodiment, the small-diameter part 1594 has the first region 410b and the second region 410c having a larger outer diameter than that of the first region 410b. Further, the wall surface 1598 is part of the second region 410c which is formed at the boundary between the first region 410b and the second region 410c and configured as the restriction part 410. The first region 410b and the second region 410c are example embodiments that correspond to the “first region” and the “second region”, respectively, according to the present invention.
When the tool holder 159 is press-fitted into the cylinder 129, the wall surface 1598 (the restriction part 410) comes in contact with the ring spring 1297 (the stop part 420). As a result, the tool holder 159 and the cylinder 129 are integrated together, and the tool holder 159 is prevented from further moving forward.
Like in the hammer drill 100 of the third embodiment, in the hammer drill 100 of the fourth embodiment, the tool holder 159 and the cylinder 129 can be separated from each other by moving the tool holder 159 rearward.
A hammer drill 100 according to a fifth embodiment of the present invention is now explained with reference to
Specifically, the restriction part 410 of the tool holder 159 is a flange 1599 formed on the periphery of a large-diameter part 1595. Thus, in the large-diameter part 1595, a region having the flange 1599 forms the second region 410c and a region not having the flange 1599a forms the first region 410b.
Further, the stop part 420 of the cylinder 129 is a wall surface 1298. The wall surface 1298 is provided by forming regions having different diameters in the inner periphery of a small-diameter part 1294. Specifically, the wall surface 1298 is formed by a step at the boundary between the regions having different diameters. The front one of the regions having different diameters in the small-diameter part 1294 has a smaller diameter than the rear region.
When the tool holder 159 is press-fitted into the cylinder 129, the flange 1599 comes into contact with the wall surface 1298. As a result, the tool holder 159 and the housing cylinder 129 are integrated together, and the tool holder 159 is prevented from further moving forward.
Like in the hammer drill 100 of the third embodiment, in the hammer drill 100 of the fifth embodiment, the tool holder 159 and the cylinder 129 can be separated from each other by moving the tool holder 159 rearward.
A hammer drill 100 according to a sixth embodiment of the present invention is now explained with reference to
Specifically, the restriction part 410 of the tool holder 159 is a wall surface 15910. The wall surface 15910 is formed by forming regions having different diameters in the outer periphery of a small-diameter part 1594. Thus, the small-diameter part 1594 has the first region 410b in its front region and the second region 410c in its rear region. The second region 410c protrudes from the first region 410b at the boundary between the first region 410b and the second region 410c and forms the wall surface 15910. Further, the stop part 420 of the cylinder 129 is a projection 1299. The projection 1299 is formed by protruding a peripheral edge of the front open end 1291 inward.
When the tool holder 159 is press-fitted into the cylinder 129, the wall surface 15910 comes into contact with the projection 1299. As a result, the tool holder 159 and the cylinder 129 are integrated together, and the tool holder 159 is prevented from further moving forward.
Like in the hammer drill 100 of the third embodiment, in the hammer drill 100 of the sixth embodiment, the tool holder 159 and the cylinder 129 can be separated from each other by moving the tool holder 159 rearward.
In the above-described embodiments, the handgrip 109 is formed in a cantilever form extending downward from the motor housing 103, but the form of the handgrip 109 should not be construed in a limiting sense. For example, the handgrip 109 may be formed in a loop shape such that the distal end of the handgrip 109 is further connected to the motor housing 103.
In the above-described embodiments, the output shaft 111 of the electric motor 110 is arranged to extend in parallel to the axis of the hammer bit 119, but the arrangement of the output shaft 111 should not be construed in a limiting sense. For example, the output shaft 111 of the electric motor 110 may be arranged to cross the axis of the hammer bit 119. In this case, it is preferred that the output shaft 111 and the intermediate shaft 116 are engaged with each other via a bevel gear. Further, it is preferred that the output shaft 111 is arranged perpendicularly to the axis of the hammer bit 119.
In the above-described embodiments, the pinion gear 113 and the driven gear 117 are formed as a helical gear, but the gear should not be construed in a limiting sense. For example, a gear such as a spur gear and a bevel gear may be used.
In view of the above, the impact tool according to this invention can be further provided with the following features. Each of the features can be used separately or in combination with the other, or in combination with the claimed invention.
(Further Aspect 1)
An impact tool, which is configured to perform a hammering operation on a workpiece by driving a tool accessory in a prescribed longitudinal direction, comprising:
a tool holder that holds the tool accessory such that the tool accessory protrudes from a front end of the tool holder, and a striking mechanism part that drives the tool accessory in the longitudinal direction, wherein:
a side of the front end of the tool holder in the longitudinal direction of the impact tool is defined as a front side, and a side opposite to the front side is defined as a rear side,
the striking mechanism part includes a housing cylinder, a piston that is housed in the housing cylinder and caused to reciprocate in the longitudinal direction between the front side and the rear side, a striking element, and an air chamber that is defined between the piston and the striking element, the striking mechanism part being configured such that the striking element is driven by pressure fluctuations which are caused within the air chamber by the reciprocating movement of the piston and the tool accessory is driven in the longitudinal direction via a striking force of the striking element,
the housing cylinder has a front open end on the front side and a rear open end on the rear side,
the tool holder and the housing cylinder are integrated together when the tool holder is press-fitted into the housing cylinder up to a prescribed position from the rear open end toward the front open end, and
further comprising a preventing mechanism,
the preventing mechanism being configured to prevent the tool holder from further moving to the front side when the tool holder and the housing cylinder are integrated together.
(Further Aspect 2)
The impact tool as defined in further aspect 1, wherein the preventing mechanism comprises a fixed member separate from the tool holder and the housing cylinder.
(Further Aspect 3)
The impact tool as defined in further aspect 2, wherein the fixed member is arranged on an outer periphery of the tool holder.
(Further Aspect 4)
The impact tool as defined in further aspect 1, wherein:
the outer periphery of the tool holder has a first region and a second region protruding from the first region in a direction crossing the longitudinal direction, and
the preventing mechanism comprises the second region.
(Further Aspect 5)
The impact tool as defined in any one of further aspects 1 to 4, wherein:
the tool holder and the housing cylinder which are integrated together are configured to be rotationally driven around the longitudinal direction, and
the impact tool is capable of performing operation on the workpiece by rotation.
(Further Aspect 6)
The impact tool as defined in any one of further aspects 1 to 5, wherein:
the striking element is configured to reciprocatingly slide in the longitudinal direction between the front side and the rear side within the tool holder, and
the tool holder has a sliding guide part that guides reciprocating slide of the striking element.
The above-described embodiments are representative examples for embodying the present invention, and the present invention is not limited to the constructions that have been described as the representative embodiments. Correspondences between the features of the embodiments and the features of the invention are as follow:
The hammer drill 100 is an example embodiment that corresponds to the “impact tool” according to the present invention. The hammer bit 119 is an example embodiment that corresponds to the “tool accessory” according to the present invention. The body housing 101 is an example embodiment that corresponds to the “body” according to the present invention. The central axis 100a, the extending axis 100b and the central plane 100c are example embodiments that correspond to the “central axis”, the “extending axis” and the “prescribed plane”, respectively, according to the present invention. The electric motor 110 is an example embodiment that corresponds to the “driving motor” according to the present invention. The first body element 101a and the holding member 130 are example embodiments that correspond to the “first body element”, and the second body element 101b and the bearing support part 107 are example embodiments that correspond to the “second body element” according to the present invention. The striking mechanism 140 is an example embodiment that corresponds to the “striking mechanism” according to the present invention. The vibration reducing mechanism 200, the first guide shaft 170a, the first elastic member 210a, the second elastic member 210b and the weight part 220 are example embodiments that correspond to the “vibration reducing mechanism”, the “guide part”, the “first elastic member”, the “second elastic member” and the “weight part”, respectively, according to the present invention. The cushioning mechanism 300 is an example embodiment that corresponds to the “cushioning mechanism” according to the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-229930 | Nov 2014 | JP | national |
| 2014-229931 | Nov 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/081796 | 11/11/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/076377 | 5/19/2016 | WO | A |
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| 20170320206 A1 | Nov 2017 | US |
