Makita Corporation

Honda Giken Kogyo Kabushiki Kaisha

Shin-ichi Nakane

Manabu Sugimoto

Shingo Umemura

Koki Hyodo

Kazuyoshi Horikawa

A rechargeable impact screwdriver ( ) includes a housing ( ) and a brush holder ( ). The brush holder ( ) in turn includes a circular main holder body ( ) and a bearing box ( ) which contains a ball bearing and is coaxially and integrally formed with the main holder body ( ). A pair of carbon brushes ( ) is inserted into the bearing box ( ) so as to come into pressing contact with a motor shaft ( ) which is supported by the ball bearing of the a bearing box ( ). The brush holder ( ) is elastically supported within the housing ( ) by four rubber pins ( ) which are mounted in the main holder body ( ) and in bosses ( ) of the housing ( ) on the opposite ends thereof.

Structure for accommodating a motor

A battery pack ( ) has two female terminals ( ) each including two pairs of elastic plates ( ). Each pair of elastic plates ( ) are arranged symmetrically about a base plate ( ). Each elastic plate ( ) includes a parallel portion ( ) oriented parallel to its counterpart of the paired elastic plate ( ). Also included in each plate ( ) is a contact pressure portion ( ) which is bent from one end the parallel portion ( ) so as to extend into contact with its counterpart of the paired elastic plate ( ). The contact pressure portion ( ) is bent back at the contact point such that a small gap is formed between the free ends of the paired pressure portions. A device to which the battery pack ( ) is attached, such as an electric power tool or a charger, includes male terminals ( ) to be coupled to the pack. By specifying the length of the male terminals ( ), an appropriate level of contact pressure can be selected for the terminals ( ).

Structure of electrical terminals for establishing electrical contact between a battery pack and an electrical device

A battery-charging system is provided that does not require removal of batteries from an impact screwdriver (1) for recharging. The battery-charging system includes the impact screwdriver and a charger (20). The impact screwdriver (1) has a nose (3a) to which a tool bit is attached. The impact screwdriver additionally includes a grip handle (4) containing a battery unit (5) whose terminals (10) for recharging are exposed in a surface of a protrusion (7) of the grip handle. The charger (20) includes a charger circuit encased in an enclosure having a base (21) covered with a housing (22). The housing of the charger is provided with a first receiving recess (29) which can receive the nose (3a) of the screwdriver and a second receiving recess (30) which can receive the protrusion (7) of the screwdriver. The system additionally includes a pair of charge terminals of the charger circuit that resiliently projects into the second receiving recess (30). The charger circuit terminals are brought into electrical contact with the corresponding terminals in the protrusion of the impact screwdriver when the screwdriver is set on the charger. While the battery unit is charged, the entire impact screwdriver (1), not the battery unit alone, is set on the charger (20) with the nose placed in the first receiving recess and the protrusion in the second receiving recess.

Growing community of inventors

Okazaki, Japan

Shin-ichi Nakane