Abstract: A double piston and belt type continuously variable transmission comprises a primary pulley provided with a primary piston chamber and a primary clamp chamber; a secondary pulley provided with a secondary piston chamber and a secondary clamp chamber; and an endless belt operatively put around the primary and secondary pulleys. A switching circuit is arranged to connect both the primary and secondary clamp chambers to either one of the primary and secondary piston chambers, which shows a higher hydraulic pressure than the other.

Abstract: A gear change control system of a belt-type continuously variable transmission includes: a movable pulley piston chamber for causing a thrust force to a movable pulley varying a groove width of primary pulley and secondary pulley. The movable pulley piston chamber has double-piston constitution including: a primary clamp chamber and a secondary clamp chamber, for causing a clamp force of clamping the belt, and a cylinder chamber including a primary pulley cylinder chamber and a secondary pulley cylinder chamber, for causing a differential thrust force at a gear change. A clamp chamber oil pressure setting section sets up a clamp chamber oil pressure by the following calculation: dividing the one of the primary thrust force and the secondary thrust force by addition of: applied pressure area of one of the primary clamp chamber and the secondary clamp chamber, and applied pressure area of the cylinder chamber on a selected side.

Abstract: A double piston and belt type continuously variable transmission comprises a primary pulley provided with a primary piston chamber and a primary clamp chamber; a secondary pulley provided with a secondary piston chamber and a secondary clamp chamber; and an endless belt operatively put around the primary and secondary pulleys. A switching circuit is arranged to connect both the primary and secondary clamp chambers to either one of the primary and secondary piston chambers, which shows a higher hydraulic pressure than the other.

Abstract: A centrifugal hydraulic pressure cancel chamber is provided between a fixed wall and a piston. The fixed wall is formed adjacent to a piston chamber. The piston chamber exerts a centrifugal hydraulic pressure to move a movable pulley portion. The piston directly presses the movable pulley portion with the centrifugal hydraulic pressure exerted from the piston chamber. The centrifugal hydraulic pressure cancel chamber exerts a centrifugal hydraulic pressure with a supplied centrifugal hydraulic pressure cancel fluid to cancel the centrifugal hydraulic pressure exerted from the piston chamber. A supply passage is provided in a shaft supporting the movable pulley portion, and supplies the centrifugal hydraulic pressure cancel fluid to the centrifugal hydraulic pressure cancel chamber. The centrifugal hydraulic pressure cancel fluid flows between the centrifugal hydraulic pressure cancel chamber and the supply passage liquid-tightly.

Abstract: A gear change control system of a belt-type continuously variable transmission includes: a movable pulley piston chamber for causing a thrust force to a movable pulley varying a groove width of primary pulley and secondary pulley. The movable pulley piston chamber has double-piston constitution including: a primary clamp chamber and a secondary clamp chamber, for causing a clamp force of clamping the belt, and a cylinder chamber including a primary pulley cylinder chamber and a secondary pulley cylinder chamber, for causing a differential thrust force at a gear change. A clamp chamber oil pressure setting section sets up a clamp chamber oil pressure by the following calculation: dividing the one of the primary thrust force and the secondary thrust force by addition of: applied pressure area of one of the primary clamp chamber and the secondary clamp chamber, and applied pressure area of the cylinder chamber on a selected side.

Abstract: A method for working a die for use with a Fresnel lens, the method being intended to work in an original die plate having a Fresnel molding groove with wall surfaces corresponding to a lens surface and a non-lens surface of the Fresnel lens. A cutting tool having one piece of edge line continuing to a blade end is constructed as a cutting edge. The blade end has formed therein a notched portion which connects the one piece of edge line and another piece of edge line. Thereby, while a relative rotating movement around a center line of the die is made between the cutting tool and the original die plate, the cutting tool is fed into the original die plate with the cutting edge being used as the leading blade.

Abstract: Disclosed is a working method of a die which can prevent the decrease in the service life of a cutting tool due to the chip-off of a tip thereof and add an additional value to the Fresnel lens. The working method is the one for working a die for use for a Fresnel lens, the method being intended to work in an original die plate a Fresnel molding groove having wall surfaces corresponding to a lens surface and a non-lens surface of the Fresnel lens, wherein there is used a cutting tool wherein one piece of edge line continuing to a blade end is constructed as a cutting edge; and the blade end has formed therein a notched portion which connects the one piece of edge line and another piece of edge line.

Abstract: A framed structure includes a plurality of base units each formed of three elongate compression members disposed so as to cross one another. Tension members are arranged to be interconnected with respective compression members forming a triangular planar units. The triangular planar units being arranged to form a self-supporting structure or base unit. A plurality of base units being interconnected in a continuous fashion such that one of the compression members in one of the base units serves as one of the compression members in an adjacent base unit.