ELECTRIC TOOL

Abstract

A power tool (1) is capable of automatically returning. The power tool (1) comprises an oil tank (4), a hydraulic pump (6), a motor (7), a flow channel section (5), a trigger lever (21), a first connecting piece (11) connecting the trigger lever (21) to an activation switch (2b), a second connecting piece (12) connecting the trigger lever (21) to a return switch (22), and a spring (23) biasing the trigger lever (21) in a return direction of the trigger lever (21). The flow channel section (5) includes a pressure-increasing flow channel (5a) connected to the cylinder section (3), a return flow channel (5b) connected to the oil tank (4), a check valve (25) that opens and closes the return flow channel (5b), and a return pin (24) that pushes the check valve (25) to open the return flow channel (5b).

Description

Technical FieldThe present invention relates to a hydraulic power tool.Prior ArtIn the related art, a hydraulic cutting tool has been proposed in which hydraulic oil is supplied by bringing one end of a start switch lever (equivalent to a release lever) into contact with a power switch (equivalent to an activation switch) and bringing the other end of the activation switch lever into contact with an operation lever of a check valve (equivalent to a check valve) (PTL 1: JP 2001-009630 A). Furthermore, a hydraulic crimping tool has been proposed in which a slide relief button for operating a relief valve (synonym: check valve) is provided via a lever in a vicinity of a power switch having a switch handle (synonym: release lever). While an operation of the shift lever is controlled, a hydraulic oil is supplied and released by operating the shift lever (PTL 2: JP 2000-343448 A and PTL 3: JP 2000-343452 A). A compression or cutting tool has been proposed that includes a feedback device having a control substrate that delays opening of a check valve (synonym: check valve), a servo motor, a cam, and a lever that engages with a closure of a check valve (synonym: check valve). The compression or cutting tool includes a switch that controls the servo motor to bring the lever to a position in which the check valve is kept open when an activation switch is released and the lever is brought to a position in which the check valve is closed when the activation switch is operated (PTL 4: JP 2017-213671 A).List of Citer ListsPatent LiteraturePTL 1: JP 2001-009630 APTL 2: JP 2000-343448 APTL 3: JP 2000-343452 APTL 4: JP 2017-213671 ASummary of the InventionTechnical ProblemThe power tools disclosed in PTL 1 to PTL 3 are necessarily limited to a gun-type main body due to a structure in which the trigger lever and the activation switch are close to each other and the trigger lever and the actuation lever of the check valve are close to each other, and cannot be applied to straight-type main bodies. The power tool disclosed in PTL 4 has a complicated structure in which only the servomotor for closing the check valve is provided. As a result, the power tool requires a large-sized configuration, requires additional component costs, and is less easily downsized.Solution of the ProblemThe present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a power tool capable of automatically returning and having a small configuration and excellent workability.The present invention is realized using the solutions disclosed below.According to the present invention, there is provided an electric tool including: a main body in which a cylinder portion is disposed; and a work attachment connected to the main body and operated by a hydraulic pressure of the cylinder portion. The main body includes an oil tank, a hydraulic pump for supplying hydraulic oil in the oil tank to the cylinder portion, a motor for driving the hydraulic pump, a rechargeable battery for supplying the motor with electric power, a flow channel portion through which the hydraulic oil flows, a trip lever, a first link connecting the trip lever to an activation switch, a second link connecting the trip lever to a return switch, and a spring biasing the trip lever in a return direction of the trip lever. The flow passage portion includes a pressure increasing flow passage connected to the cylinder portion of the oil tank to supply the hydraulic oil, a return flow passage connected to the oil tank of the cylinder portion to return the hydraulic oil, a check valve opening and closing the return flow passage, and a return pin pressing the check valve to open the return flow passage. The trigger lever is disposed on a side opposite to a side on which the return switch is disposed with respect to an axis passing through the cylinder portion.According to this configuration, the activation switch and the release lever are connected by the first link, and the return switch and the release lever are connected by the second link. Accordingly, with a simple configuration, while a straight type main body can be adopted, it can be achieved. A series of operations from a pressure increasing operation to a returning operation can be performed by operating the trigger lever in a combination of the activation switch, the first link, the trigger lever, and the second link. Accordingly, an automatic return type electric tool having a compact structure and excellent workability can be produced.It is preferable that the first connector includes: a first contact portion that is in contact with the activation switch, a rod-shaped portion that is disposed along the axis, and a second contact portion that is in contact with the trigger lever, and that the second connector includes: a third contact portion that is connected to the return switch, an annular portion that is disposed in a direction intersecting the axis, and a support portion that is supported by the trigger lever. According to this configuration, both the first link and the second link can be operated simply by operating the trigger lever, and a configuration suitable for the straight type main body can be used.As an example, the main body has a configuration including a controller for controlling the motor and a selector switch for limiting an operation range of the trigger lever. The motor, the activation switch and the control device are arranged one behind the other along the axis. The selector switch is disposed close to the trigger lever. According to this configuration, since the selection switch is provided, a configuration in which safety is further improved can be selected. If necessary, the work can be performed simply by switching between an automatic return operation and a hold operation.As an example, the flow passage portion includes a configuration having a pressure regulating valve that regulates a pressure to a high pressure side. The pressure regulating valve is disposed closer to the cylinder portion than the check valve. According to this configuration, the pressure regulating valve can be connected to the cylinder portion close position of the recirculation flow passage, and interference with the second joint can be avoided. Thus, a reasonable flow channel configuration can be achieved.As an example, a configuration has a pressure increasing mode in which the trigger lever is pressed to turn on the activation switch and supply the hydraulic oil to the cylinder portion, a holding mode in which the trigger lever is returned to an intermediate position to turn off the activation switch in a state in which the check valve is closed to hold the hydraulic oil supplied to the cylinder portion, and a returning mode in which the trigger lever is returned to a home position to open the check valve and return the hydraulic oil to the oil tank. According to this configuration, the automatic returning operation and the holding operation can be switched only by operating the release lever.Advantageous Effects of the InventionAccording to the present invention, by a simple configuration using a first connector and a second connector, a straight electric tool having automatic recovery, small configuration, and excellent workability can be realized.Brief Description of the DrawingsFIG. 1 is a schematic perspective view showing an example of a power tool according to an embodiment of the present invention. FIG. 2A is a schematic front view of the power tool shown in FIG. 1, FIG. 2B is a schematic right side view of the power tool shown in FIG. 1, FIG. 2C is a schematic rear view of the power tool shown in FIG. 1, and FIG. 2D is a schematic left side view of the power tool shown in FIG. 1. FIG. 3A is a schematic diagram of the internal structure when a main body is viewed from a back side in a pressure increasing mode, and FIG. 3B is a schematic longitudinal sectional view of FIG. 3A. FIG. 4A is a schematic diagram of the internal structure when the main body is viewed from the rear side in a holding mode, and FIG. 4B is a schematic longitudinal sectional view of FIG. 4A. FIG. 5A is a schematic diagram of the internal structure when the main body is viewed from the rear side in a returning mode, and FIG. 5B is a schematic longitudinal sectional view of FIG. 5A. FIG. 6 is a schematic longitudinal sectional view when the main body is viewed from a left side. FIG. 7 is a sectional view taken along a line VII-VII in FIG. 6, and is a schematic cross-sectional view. FIG. 8A is a schematic perspective view of a first connector according to the present embodiment, FIG. 8B is a schematic front view of FIG. 8A, FIG. 8C is a schematic plan view of FIG. 8A, and FIG. 8D is a schematic bottom view of FIG. 8A. FIG. 9A is a schematic front view of a second connector according to the present embodiment, FIG. 9B is a schematic plan view of FIG. 9A, FIG. 9C is a schematic bottom view of FIG. 9A, and FIG. 9D is a schematic side view of FIG. 9A. FIG. 10A is a schematic perspective view showing a state in which the second link according to the present embodiment is mounted on a trigger lever, and FIG. 10B is a schematic side view of FIG. 10A. FIG. 11A is a schematic perspective view of a selector switch according to the present embodiment, FIG. 11B is a schematic structural diagram illustrating a spatial relationship between the selector switch and the trigger lever in the returning mode according to the present embodiment, and FIG. 11C is a schematic structural diagram illustrating a spatial relationship between the selector switch and the trigger lever in the holding mode according to the present embodiment.DESCRIPTION OF EMBODIMENTSHereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present embodiment is a power tool 1 including an electric crimping machine, an electric compressor, and an electric cutter. In all the drawings for describing the embodiment, the elements having the same functions are assigned the same reference numerals, and repeated description of elements assigned the same reference numerals may be omitted in some cases.FIGS. 1 to 7 are schematic structural diagrams showing an example of the electric tool 1 according to the present embodiment. The electric tool 1 includes a main body 2 in which a cylinder portion 3 is disposed, and a working cap 31 connected to the main body 2 and operated by a hydraulic pressure of the cylinder portion 3. In this example, a tool 31a in the work attachment 31 is fixed to a piston 3a of the cylinder portion 3. In the present embodiment, a wireless tool used by a worker who holds the tool on a construction site with one hand is provided, and the tool is the multifunctional electric tool 1 in which the work attachment 31 is replaced. The working head 31 in FIG. 1 is an example used as an electric crimping machine, and the tool 31 ais a die. In order to facilitate the description of a spatial relationship of the individual parts of the electric tool 1, the directions are indicated by arrows X, Y and Z in the drawings. The power tool 1 is normally operated in any direction.FIG. 2A is a schematic front view of the power tool 1, FIG. 2B is a right side view of FIG. 2A, FIG. 2C is a rear view of FIG. 2A, and FIG. 2D is a left side view of FIG. 2A. The main body 2 includes a trigger lever 21, a return switch 22, and a selection switch 28. The selection switch 28 is disposed on a side on which the trigger lever 21 is disposed with respect to the axis P 1 passing through the main body 2 in the longitudinal direction. The main body 2 includes an adapter 8 to which a rechargeable battery 9 as a battery pack is connected.FIG. 3A is a schematic diagram of the internal structure when the main body 2 is viewed from a rear side in a pressure increasing mode, and FIG. 3B is a schematic longitudinal sectional view of FIG. 3A. When the trigger lever 21 is pressed to turn on the activation switch 2 b, the pressure increasing mode for supplying a hydraulic oil 4 ato the cylinder portion 3 is set. When the main body 2 is in the pressure increasing mode, it is used for compressing or crimping a compression terminal, for example.FIG. 4A is a schematic diagram of the internal structure when the main body 2 is viewed from the rear side in a holding mode, and FIG. 4B is a schematic longitudinal sectional view of FIG. 4A. After the compression or crimping work, the release lever 21 is reset to an intermediate position, an activation switch 2 bis turned off with the check valve 25 closed, and a holding mode for holding the hydraulic oil 4 asupplied to the cylinder portion 3 is set. For example, since the main body 2 is in the holding mode, the crimping or compression work can be repeatedly performed in a short time, and by holding the compression terminal or the crimp barrel in a gripped state, an operator can adjust the connection position with an electric wire.FIG. 5A is a schematic diagram of the internal structure when the main body 2 is viewed from the back side in a return mode. FIG. 5B is a schematic longitudinal sectional view of FIG. 5A. After a series of compression or crimping operations, the release lever 21 is returned to an initial position and the check valve 25 is opened to set the return mode for returning the hydraulic oil 4 ato an oil tank 4. Since the main body 2 is in the returning mode, the power tool 1 is in an initial state. Further, when necessary, a worker may press the return switch 22 to operate a return pin 24, press the check valve 25 to open a return flow passage 5 b, and in some cases return the hydraulic oil 4 ato the oil tank 4.FIG. 6 is a schematic longitudinal sectional view when the main body 2 is viewed from a left side. FIG. 7 is a sectional view taken along a line VII-VII in FIG. 6, and is a schematic cross-sectional view. The power tool 1 includes a swash plate cam 6 athat is rotated by being connected to a drive shaft 7 aof a motor 7, and a plurality of pistons 6 bthat are arranged about an axis P 1 passing through the drive shaft 7 ain the cylinder portion 3 and reciprocates while being in contact with the swash plate cam 6 a. The oil tank 4 is located at a position connecting the cylinder portion 3 and a hydraulic pump 6. The oil tank 4 is connected to the hydraulic pump 6 via a suction check valve 6 d. Further, the oil tank 4 is connected to the cylinder portion 3 via a drain check valve 6 c.The main body 2 includes the oil tank 4, the hydraulic pump 6 that supplies the hydraulic oil 4 ain the oil tank 4 to the cylinder portion 3, the motor 7 that drives the hydraulic pump 6, the rechargeable battery 9 that supplies the motor 7 with electric power, a flow passage portion 5 through which the hydraulic oil 4 apasses, and the trigger lever 21 that operates the work attachment 31. Further, in a housing 2 aof the main body 2, a first connector 11 connecting the trigger lever 21 and the activation switch 2 b, a second connector 12 connecting the trigger lever 21 and the return switch 22, and a helical spring 23 biasing the trigger lever 21 in a return direction of the trigger lever 21 are disposed.In the cylinder portion 3, the piston 3 ais disposed in a piston chamber 3 b, and a coil spring 3 cis disposed along an outer periphery of the piston 3 aso as to coincide with an axis of the piston 3 a. The hydraulic pump 6 supplies the hydraulic oil 4 astored in the oil tank 4 to the cylinder portion 3. Further, the main body 2 includes the motor 7 connected to the hydraulic pump 6 for driving the hydraulic pump 6, and a controller 27 for controlling the drive of the motor 7.The flow passage portion 5 includes a pressure increasing flow passage 5 athat is connected from the oil tank 4 to the cylinder portion 3 and supplies the hydraulic oil 4 a, and the return flow passage 5 bthat is connected from the cylinder portion 3 to the oil tank 4 and returns the hydraulic oil 4 a. The check valve 25 is disposed in the path of the recirculation flow passage 5 b, and the recirculation pin 24 is disposed to press the check valve 25 so as to open the recirculation flow passage 5 b. Further, in the flow passage portion 5, a pressure control valve 26 that controls a pressure on a high pressure side is connected to the path of the recirculation flow passage 5 b, the pressure control valve 26 being disposed closer to the cylinder portion 3 than the check valve 25.The adapter 8 is disposed in the main body 2, and the rechargeable battery 9 that supplies the motor 7 and the controller 27 with electric power is detachably connected to the adapter 8 as a battery pack. As an example, the rechargeable battery 9 is a lithium ion battery, a nickel-hydrogen battery, or another known rechargeable battery. According to this configuration, the electric tool 1 is excellent in portability. For example, the hydraulic pump 6, the motor 7, the activation switch 2 b, the adapter 8, and the rechargeable battery 9 are sequentially arranged along the axis P 1. The activation switch 2 bfor energizing the motor 7 is disposed between the motor 7 and the controller 27. According to this configuration, a reasonable configuration in which the arrangement of the electronic system components and the arrangement of the hydraulic system components are separated can be achieved.FIG. 8A is a schematic perspective view of the first connector 11, FIG. 8B is a schematic front view of FIG. 8A, FIG. 8C is a schematic plan view of FIG. 8A, and FIG. 8D is a schematic bottom view of FIG. 8A. The first joint 11 includes a first contact portion 11 athat is in contact with the activation switch 2 b, a rod-shaped part 11 bdisposed along the axis P 1, and a second contact portion 11 cin contact with the release lever 21.FIG. 9A is a schematic front view of the second connector 12, FIG. 9B is a schematic plan view of FIG. 9A, FIG. 9C is a schematic bottom view of FIG. 9A, and FIG. 9D is a schematic side view of FIG. 9A. The second link 12 includes a third contact portion 12 athat engages with the return switch 22, an annular part 12 bdisposed in a direction intersecting the axis P 1, and a support portion 12 cthat is supported by the trigger lever 21. As an example, the second joint 12 is formed by compression working of a cemented carbide plate.FIG. 10A is a schematic perspective view showing a state in which the second link 12 is mounted on the trigger lever 21, and FIG. 10B is a schematic side view of FIG. 10A. A fourth contact portion 21 a, which is in contact with the second contact portion 11 cof the first connector 11, is formed on one end side in the longitudinal direction of the trigger lever 21. The spring 23 is disposed near the center in the longitudinal direction of the trigger lever 21, and a convex-shaped receiving portion 21 bis provided on an opposite side to the fourth contact portion 21 awith respect to the spring 23. A through hole of the support portion 12 cof the second link 12 is pivotally attached to the receiving portion 21 bof the trigger lever 21.FIG. 11A is a schematic perspective view of the selector switch 28. FIG. 11B is a schematic structural diagram showing a spatial relationship between the selector switch 28 and the trigger lever 21 in the returning mode. FIG. 11C is a schematic structural diagram showing a spatial relationship between the selection switch 28 and the release lever 21 in the holding mode. The release lever 21 is pivotally supported by a support pin 29 attached to the housing 2a of the main body 2. The selector switch 28 is a plate-shaped body having an elliptical cross section and is fixed to the housing 2 ain the direction intersecting the axis P 1. In the selection switch 28, on one end side in the short direction, a second limiting surface 28 ais formed, which is in contact with a first limiting surface 21 cof the trigger lever 21. Further, in the selection switch 28, a fourth limiting surface 28 bcontacting a third limiting surface 21 dof the trigger lever 21 is formed above one end side in the short direction.The selection switch 28 is disposed in the vicinity of the release lever 21 and limits an operation range of the release lever 21, and as shown in FIG. 11B, when the selection switch 28 is pressed, the release lever 21 is brought into a non-contact state in which it does not come into contact with the selection switch 28, and the operation range of the release lever 21 is not limited. Therefore, automatic return is possible. As shown in FIG. 11C, when the selector switch 28 is pulled out, the trigger lever 21 is returned to the intermediate position, and the trigger lever 21 is brought into a state of being in contact with the selector switch 28 in the holding mode. In this state, the operating range of the trigger lever 21 is limited. Therefore, the holding mode is maintained. At this time, when the selector switch 28 is pushed to an intermediate position, it can limit the operating range of the trigger lever 21 so that the trigger lever 21 does not move from the initial position. Since the selection switch 28 is provided, a configuration with further improved reliability can be achieved. If necessary, it is possible to easily operate by switching between an automatic returning operation and a holding operation.In the above-described example, the push type dial 28 is described, but the configuration is not limited to this example. For example, instead of the push type selection switch, a slide type selection switch or a selection type selection switch may be provided. In the example described above, the configuration in which the second joint 12 includes the annular part 12 bis described, but the configuration is not limited to this example. For example, instead of the annular portion 12 b, the second joint may include an arcuate portion.In the above-described example, the power tool 1 is described with the straight type main body, but the configuration is not limited to this example. The present configuration can also be applied to a portable power tool. The present invention is not limited to the above-described embodiment, and various modifications may be made within the scope that does not depart from the present invention.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2001-009630 A

[0002] JP 2000-343448 A

[0002] JP 2000-343452 A

[0002] JP 2017-213671 A

[0002]

Claims

An electric tool comprising: a main body in which a cylinder portion is disposed; and a work attachment connected to the main body and operated by a hydraulic pressure of the cylinder portion, the main body comprising: an oil tank; a hydraulic pump for supplying a hydraulic oil in the oil tank to the cylinder portion; a motor for driving the hydraulic pump; a rechargeable battery for supplying electric power to the motor; a flow channel portion through which the hydraulic oil flows; a trip lever; a first connector connecting the trip lever to an activation switch; a second connector connecting the trip lever to a return switch; and a spring biasing the trip lever in a return direction of the trip lever, the flow channel portion comprising: a pressure increase flow channel, which is connected to the cylinder portion of the oil tank to supply the hydraulic oil, a return flow passage connected to the oil tank of the cylinder portion to return the hydraulic oil, a check valve that opens and closes the return flow passage, and a return pin that presses the check valve to open the return flow passage, and the trip lever is disposed on a side opposite to a side on which the return switch is disposed with respect to an axis passing through the cylinder portion.The power tool according to claim 1, wherein the first connector includes: a first contact portion that is in contact with the activation switch, a rod-shaped portion that is disposed along the axis, and a second contact portion that is in contact with the trigger lever, and the second connector includes: a third contact portion that is connected to the return switch, an annular portion that is disposed in a direction intersecting the axis, and a support portion supported by the trigger lever.The power tool according to claim 1, wherein the main body comprises: a controller for controlling the motor; and a selection switch for limiting an operation range of the trigger lever, the motor, the activation switch, and the controller are arranged one behind the other along the axis, and the selection switch is arranged close to the trigger lever.The power tool according to claim 2, wherein the main body comprises: a controller for controlling the motor; and a selection switch for limiting an operation range of the trigger lever, the motor, the activation switch, and the controller are arranged one behind the other along the axis, and the selection switch is arranged close to the trigger lever.The electric tool according to claim 1, wherein the flow passage portion includes a pressure regulating valve that regulates a pressure to a high pressure side, and the pressure regulating valve is disposed closer to the cylinder portion than the check valve.The electric tool according to claim 2, wherein the flow passage portion includes a pressure regulating valve that regulates a pressure to a high pressure side, and the pressure regulating valve is disposed closer to the cylinder portion than the check valve.The power tool according to claim 1, wherein the power tool has: a pressure increasing mode in which the trigger lever is pressed to turn on the activation switch and supply the hydraulic oil to the cylinder portion; a holding mode in which the trigger lever is returned to an intermediate position to turn off the activation switch in a state in which the check valve is closed to hold the hydraulic oil supplied to the cylinder portion; and a returning mode in which the trigger lever is returned to a home position to open the check valve and return the hydraulic oil to the oil tank.The power tool according to claim 2, wherein the power tool has: a pressure increasing mode in which the trigger lever is pressed to turn on the activation switch and supply the hydraulic oil to the cylinder portion; a holding mode in which the trigger lever is returned to an intermediate position to turn off the activation switch in a state in which the check valve is closed to hold the hydraulic oil supplied to the cylinder portion; and a returning mode in which the trigger lever is returned to a home position to open the check valve and return the hydraulic oil to the oil tank.

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