Abstract: A wing door opening/closing apparatus including a link mechanism and a spring for swinging up a wing door 1. This wing door opening/closing apparatus is made up by plural wing door opening/closing devices A and B. The disparity of the moments generated by one wing door opening/closing device A in the plural wing door opening/closing devices A and B is compensated by a moment generated by the other wing door opening/closing device B.

Abstract: An apparatus for opening and closing a wing door 1 of a truck, which is hinged to a vehicle body of a truck is accommodated in a space defined by a frame 2 when the wing door 1 is closed. The apparatus comprises a first arm 4 pivotally mounted on the vehicle body so as to pivotally move in association with the opening and closing of the wing door; a second arm 6 swingably linked between one end of the first arm 4 and the wing door 1; a spring 16 having one end supported relative to the vehicle body for generating a biasing force to lift up the wing door 1; a spring rod 11 connected to the other end of the spring 16 so as to move in association with the extension and retraction of the spring 16; a third arm 9 swingably linked between the other end of the first arm 4 and the spring rod 11; and a guide 13 for guiding the spring rod 11 or a link point 10 between the third arm 9 and the spring rod 11 for moving the spring rod in a direction substantially parallel with the axis of the spring 16.

Abstract: A springing up apparatus for the door (especially the rear door of a cargo box) of a van-type truck is constructed by pivotally attaching the second end of an arm A having a first end pivotally attached to a cargo box body and a second end of an arm B having a first end pivotally attached to the door of the cargo box, and loading a tension spring between a prescribed point on the arm B and a prescribed point on the cargo box body or on the door of the cargo box. This makes it easy to open and close the door of the cargo box by human power. Further, use is made of a compression spring, which is provided on the roof of the cargo box, and there are additionally provided a spring cover mounting structure, which is capable of rotating about a horizontal shaft fixed to the roof, as well as a door-opening adjustment mechanism, which comprises a bracket and an adjustment disk, for adjusting initial amount of compression of the compression spring. This makes it easy to bring the door to rest at a desired position.

Abstract: A vibration damper for a vibrational mechanical body, such as a chain saw or motorcycle, which is a source of vibration, comprises a support, such as an arm of the vibrational body for manipulation, a cylindrical grip mounted on the support, and a vibration-damping means consisting of a pair of coiled springs having a row of small and large coiled portions and disposed between the support and the rigid grip, with each of the small coiled portions being engaged with and supported by the support and each large coiled portion by the inner surface of the grip, whereby the vibration transmitted from the vibrational body to the support is absorbed by the vibration-damping coiled spring to control or lessen the vibration transmission to the grip.

Abstract: A vibration-damped power transmission device adapted to transmit power from a prime mover such as motor, internal combustion engine and the like, which causes a vibratory motion, to a driven body, said power transmission device being supported on a support frame which is to be prevented from vibration, characterized in that at least two vibration dampers are disposed between the housing of said power transmission device and said support frame, said vibration damper comprises a mandrel, a mass member having a cylindrical inner surface enclosing said mandrel, and at least one damping coil spring inserted between said mandrel and said cylindrical inner surface, each of said springs consisting of at least one small coiled portion engaged with or fixed to said mandrel, at least one large coiled portion engaged with or fixed to said cylindrical inner surface and at least one conically and spirally coiled portions integrally connecting said small coiled portion and said large coiled portion.