Abstract: A clutch device includes a clutch center holding output-side rotating plates alternately arranged with input-side rotating plates, and a pressure plate movable toward or away from the clutch center. The pressure plate includes pressure-side fitting teeth holding the output-side rotating plates. The clutch center includes center-side fitting teeth holding the output-side rotating plates. In a half-clutch state, a portion of one of the center-side fitting teeth overlap with a portion of one of the pressure-side fitting teeth when seen in the radial directions of an output shaft.

Abstract: A power transmission device has a pressure member 5, drive-side clutch plates, driven-side clutch plates, a clutch spring 10, a separate receiving member 11, and a back-torque limiting cam. A radially-outside restricting portion restricts radially-outward movement of the receiving member 11 relative to the pressure member 5. This maintains clearance t between a side surface 11d of the receiving member 11 and an inner peripheral wall 4e of a clutch member 4.

Abstract: A power transmission device has a pressure member (5) pressing drive-side clutch plates and driven-side clutch plates against each other or releasing a press-contact force. A clutch spring (10) urges the pressure member (5) in a direction so that the clutch plates are pressed against each other. A separate receiving member (11) is attached to the pressure member (5). A back-torque limiting cam reduces press-contact force between the clutch plates when the rotation speed of an output member exceeds the rotation speed of an input member. A rotation restricting portion (8a) restricting rotation, relative to the clutch member (4), of the pressure member (5) that has moved due to activation of the push rod (9). A clearance t is maintained between the pair of cam surfaces that constitute the back-torque limiting cam.

Abstract: A power transmission device has a pressure member (5) pressing drive-side clutch plates and driven-side clutch plates against each other or releasing a press-contact force. A clutch spring (10) urges the pressure member (5) in a direction so that the clutch plates are pressed against each other. A separate receiving member (11) is attached to the pressure member (5). A back-torque limiting cam reduces press-contact force between the clutch plates when the rotation speed of an output member exceeds the rotation speed of an input member. A rotation restricting portion (8a) restricting rotation, relative to the clutch member (4), of the pressure member (5) that has moved due to activation of the push rod (9). A clearance t is maintained between the pair of cam surfaces that constitute the back-torque limiting cam.

Abstract: A power transmission device has a pressure member 5, drive-side clutch plates, driven-side clutch plates, a clutch spring 10, a separate receiving member 11, and a back-torque limiting cam. A radially-outside restricting portion restricts radially-outward movement of the receiving member 11 relative to the pressure member 5. This maintains clearance t between a side surface 11d of the receiving member 11 and an inner peripheral wall 4e of a clutch member 4.

Abstract: A power transmitting apparatus inputs or cuts off rotational power of an input member (1) to an output member (3) by press-contacting a plurality of driving-side clutch discs (6) and a plurality of driven-side clutch discs (7) with each other or releases them. A clutch housing (2) includes the driving-side clutch discs (6). A clutch member is (4) connected to the output member (3). A pressure member (5) press-contacts the discs (6) and discs (7) with each other or releases the press-contacting force between them. Application of a resisting force, for resisting relative rotation between the clutch member (4) and the pressure member (5), can be attained. A magnitude of the resisting force is set larger than a sticking torque between the discs (6) and discs (7).

Abstract: A power transmitting apparatus inputs or cuts off rotational power of an input member (1) to an output member (3) by press-contacting a plurality of driving-side clutch discs (6) and a plurality of driven-side clutch discs (7) with each other or releases them. A clutch housing (2) includes the driving-side clutch discs (6). A clutch member is (4) connected to the output member (3). A pressure member (5) press-contacts the discs (6) and discs (7) with each other or releases the press-contacting force between them. Application of a resisting force, for resisting relative rotation between the clutch member (4) and the pressure member (5), can be attained. A magnitude of the resisting force is set larger than a sticking torque between the discs (6) and discs (7).

Abstract: A process for conveniently and efficiently preparing a 2,6-dihalogenopurine using an inexpensive starting material. A process for preparing a 2,6-dihalogenopurine, comprising treating a 2-amino-6-halogenopurine having a protective group at 7th position or 9th position with a diazotizating agent and a halogen source; and a process for preparing a 9-acyl-2-amino-6-halogenopurine, comprising treating a 2-amino-6-halogenopurine with an acylating agent in the presence of a base.

Abstract: A process for conveniently and efficiently preparing a 2,6-dihalogenopurine using an inexpensive starting material. A process for preparing a 2,6-dihalogenopurine, comprising treating a 2-amino-6-halogenopurine having a protective group at 7th position or 9th position with a diazotizating agent and a halogen source; and a process for preparing a 9-acyl-2-amino-6-halogenopurine, comprising treating a 2-amino-6-halogenopurine with an acylating agent in the presence of a base.

Abstract: A process for conveniently and efficiently preparing a 2,6-halogenopurine using an inexpensive starting material. A process for preparing a 2,6-dihalogenopurine, comprising treating a 2-amino-6-halogenopurine having a protective group at 7th position or 9th position with a diazotizating agent and a halogen source; and a process for preparing a 9-acyl-2-amino-6-halogenopurine, comprising treating a 2-amino-6-halogenopurine with an acylating agent in the presence of a base.

Abstract: A process for conveniently and efficiently preparing a 2,6-halogenopurine using an inexpensive starting material. A process for preparing a 2,6-dihalogenopurine, comprising treating a 2-amino-6-halogenopurine having a protective group at 7th position or 9th position with a diazotizating agent and a halogen source; and a process for preparing a 9-acyl-2-amino-6-halogenopurine, comprising treating a 2-amino-6-halogenopurine with an acylating agent in the presence of a base.

Abstract: A process for preparing 2,6-dichloropurine including chlorinating 2-amino-6-chloropurine with a chlorine source in the presence of a diazotizating agent.

Abstract: A process for preparing 2,6-dichloropurine including chlorinating 2-amino-6-chloropurine with a chlorine source in the presence of a diazotizating agent.

Abstract: A sensor housing pipe is secured to a back of a watch at a recess formed on an underside of the back. A sensor is housed in the sensor housing pipe. A sensor lid is provided for securing the sensor in the sensor housing pipe. The sensor lid has openings for communicating the sensor with the outside of the watch.

Abstract: A structure comprising a watch case; a pair of lugs each extending from the watch case and having an upper surface in a lower position than the upper surface of the watch case; a band; and a connector secured to the underside of the end portion of the band, the band being closely attached to the watch case by placing the end of the band on the upper surfaces of the lugs and tightening cone point screws into threaded holes provided near distal ends of the sides of the lugs so that the cone points of the screws hold firmly a pair of attachment openings provided in said connector against the watch case.

Abstract: A structure of a rotating mechanism for a watch case having a time display section, comprising a case body internally accommodating the time display section and having a lower opening, a back cover fitted into the lower opening of the case body, a retining ring secured to a lower portion of the case body, and a band attaching base engaging with the case body by being clamped between the retaining ring and the case body. The case body is adapted to rotate with respect to the band attaching base.