Hitachi Koki Co., Ltd.

Takahiro Ookubo

Masato Sakai

Masanori Okada

Takeshi Taniguchi

Hitoshi Tsuzuki

Kazutaka Iwata

Tsukasa Suzuura

Hideki Yamada

Satoshi Abe

An impact tool which transmits an impact force to a tool bit supported by a casing includes: a cylinder which is attached to the casing and has an opening on one end side thereof to which the tool bit is inserted; an intermediate element which is provided in an inside of the cylinder so as to be able to move straight, has a projection projecting in a radial direction so as to regulate a range of the straight movement, and transmits the impact force to the tool bit; and passages and which communicate a space in an inside of the cylinder at a position nearer to the tool bit than the projection with the outside of the cylinder and penetrate through the cylinder in the radial direction.

Impact tool

An impact tool includes a casing () supporting a tip tool (), a piston () provided in the casing (), an electric motor () provided in the casing (), a motion converting mechanism () provided in the casing (), and a vibration reducing mechanism () provided in the casing (). The vibration reducing mechanism () has a supporting member, which is swingable with using a fixing position (J) as a supporting point and a weight () attached to a free end side of the supporting member. In a plane including a center line (C), the gravity center (H) of the weight () and the gravity center (G) of the casing () are disposed at mutually different locations, and the fixing position (J) is disposed on the side of the gravity center (G) relative to the center line (C).

An electric boring tool comprises an electric motor, a switch trigger, a tip tool driven by driving force of the electric motor, a power transmission mechanism for transmitting the driving force of the electric motor to the tip tool as rotational force and/or hammer force, and a motor control unit for controlling speed of the electric motor in response to an extent of pulling of the switch trigger. The motor control unit subjects the electric motor to low speed control after the electric motor is started up, and controls the speed of the electric motor in response to the extent of pulling of the switch trigger when the load current of the electric motor is set value or greater during the low speed control.

Electric boring tool

An electrical power tool includes a motor, a casing, a casing, a piston, an intermediate shaft, a motion conversion mechanism, and a plurality of types of anti-vibration mechanism. The motor has a drive shaft. The casing accommodates at least the motor. The piston is driven by a rotary motion of the drive shaft. The intermediate shaft extends parallel to the drive shaft and is driven to rotate by the rotary motion of the drive shaft, the intermediate shaft defining an axial direction. The motion conversion mechanism is disposed on the intermediate shaft and is capable of moving in association with the intermediate shaft for converting the rotary motion of the drive shaft to a reciprocating motion. The motion conversion mechanism includes a first motion conversion mechanism that is connected to the piston and moves the piston in a reciprocating motion in directions substantially parallel to the axial direction of the intermediate shaft. The plurality of types of anti-vibration mechanism is accommodated in the casing.

Electrical power tool with anti-vibration mechanisms of different types

A power tool suppressing expansion of the air in a chamber and preventing lubricant encapsulated in the chamber from being leaked outside of the chamber. A communication portion communicates a speed reduction chamber with a motor housing communicating with an atmosphere. A communication passage forming component made from an elastic material is fittingly inserted into the communication portion which forms a communication passage including a plurality of impediment portions. When the air containing lubrication component is passed through the communication passage, the air collides against the impediment portions, allowing grease component to be adhered to the impediment portions.

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Hitachinaka, Japan

Takahiro Ookubo