Abstract: Accordingly, it is an object of the present invention to provide an effective technique to improve ease of operation of the power impact tool. The representative power impact tool according to the present invention includes a tool body, a tool bit, a motor, first and second switches and a mode changing mechanism. The tool bit performs a striking movement. The motor is driven only when both of the switches are turned on. The first switch is urged from the on position side to the off position side and normally held in the off position. The second switch is turned between the on position and the off position and held in one of the on and off positions unless operated to be turned to the opposite position. The mode changing mechanism switches between hammer operation modes of the tool bit. According to the first hammer mode, the user is allowed to actuate the first switch while the second switch is locked in the on position.

Abstract: The present invention realizes effective recoil reduction and idling strike prevention with a minimum constitution. In a tool holder (6), a thermal-resistant O-ring (22) is arranged between two steel washers (21,23) near the joint to the barrel (5). The O-ring (22) has a cross-sectional diameter of approximately 7 mm. The inner diameter of the O-ring (22) is made slightly greater than the diameter of a cylindrical portion (19b) formed at the rear of an intermediate element (19) and slightly smaller than the diameter of a flange (19a) formed at the rear of the cylindrical portion (19b). Likewise, the inner diameter is made slightly greater than the diameter of a recess (18b) of a striking member (18) formed in front thereof and slightly smaller than the diameter of a flange (18a) formed in front of the recess (18b).

Abstract: An airflow regulation arrangement for regulating the impact of the strikes delivered from a striking member (6) to an intermediate member (10) and a bit, thus reducing the vibration, and also for regulating the impact of recoils of the striking member (6) is disclosed for use in an electrical hammer (1). The airflow regulation arrangement comprises an air inlet (14) provided in an air chamber (5) in a cylinder (3) of the electrical hammer (1), exhaust ports (15) provided in a second air chamber (9), and air passages (16) in communication with the air inlet (14) and the exhaust ports (15). The air passages (16) are connected to choke passages (17), the cross sectional area of which is one fifth to one sixth of that of the air passages (16).

Abstract: An easily testable integrated logic circuit utilizes a plurality of flip-flops to form a feedback shift register. In some embodiments, means are provided for selectively forming the flip-flops into a feedback shift register and for selectively supplying either the flip-flop contents or a random signal as partial inputs to the combinational logic circuit. In other embodiments, the feedback shift register is coupled to the AND logic array outputs of a combinational circuit which also includes and OR logic array.

Abstract: A sorting circuit for sorting three inputs representative of numerical values into first through third outputs representative of the values in the ascending order, checks three binary bits of input sequences supplied thereto at a time from the most significant bit. When only one of the three checked bits is found to be logic "0" and logic "1" for the first time, the sequence including the only one bit represents the minimum and the maximum, respectively. As soon as only one of two bits of the sequences except for the sequence representative of the minimum is subsequently found to be logic "1," the sequence including the only one subsequently found bit represents the maximum. In this manner, the circuit produces the outputs. It is possible to form an array of such three-input-output sorting circuits and conventional two-input-output sorting circuits for use in sorting a multiplicity of inputs.

Abstract: An easily testable integrated logic circuit utilizes a plurality of flip-flops to form a feedback shift register. In some embodiments, means are provided for selectively forming the flip-flops into a feedback shift register and for selectively supplying either the flip-flop contents or a random signal as partial inputs to the combinational logic circuit. In other embodiments, the feedback shift register is coupled to the AND logic array outputs of a combinational circuit which also includes an OR logic array.