Abstract: A sand vehicle has a main frame, an auxiliary frame disposed in the main frame, a rear shaft, a pair of connection bars, and a first and a second positioning seats disposed on the auxiliary frame, a pair of torsion-resistant elements, a pair of sleeves disposed on the first positioning seat to receive the torsion-resistant elements, a connection frame disposed on the main frame, a pair of positioning bars disposed on the main frame, the main frame having two rear distal bars, a pair of pivot shafts, a pair of torsion-resistant members, a pair of collars to receive the torsion-resistant members, a pair of connection rods connected to the collars and the pivot shafts, and two rear wheels connected to the rear shaft. Each rear distal bar of the main frame has a pivot aperture. Each positioning bar has a pivot hole. The torsion-resistant elements are disposed between the positioning bars. The collars are disposed in the second positioning seat. The pivot shafts are disposed on the rear distal bars.

Abstract: A sand buggy has a main frame. A pair of connection rods are disposed on the main frame. A positioning seat which is connected to the connection rods has two lower rotating shafts. A movable mount has two pairs of lug panels to receive the lower rotating shafts. Two front shock absorbers are connected to a-suspension arm and a positioning plate. A first and a second positioning mounts are disposed on the main frame. A first movable seat is inserted in the first positioning mount. A pair of first lug plates are disposed on the first suspension link. A second movable seat is inserted in the second positioning mount. A pair of second lug plates are disposed on the second suspension link. A first rear shock absorber is positioned by the first lug plates. A second rear shock absorber is positioned by the second lug plates. A main shaft is connected to the first and the second rear shock absorbers.

Abstract: A gearbox structure of a beach cycle includes a gearbox which may transmit a power of an engine to a power shaft and a propeller shaft. A clutch mounted between the change gears of the gearbox can be shifted by a gear shift device into a neutral position, a reverse gear position and a forward gear position. The gear shift device includes a gear lever which rotates a sector shaped gear which rotates a gear shift cam shaft which is formed with a slot for driving a gear shift drive fork which shifts the clutch to the neutral position, the reverse gear position, and the forward gear position. The gearbox is further provided with a force increase gear, and the propeller shaft is additionally provided with a drive gear which meshes with a helical gear of a distance calculator which has a connecting line externally connected to an odometer.

Abstract: A transmission assembly has a frame having a through hole, a transmission gear, a driven gear, and a transmission chain surrounding the transmission gear and the driven gear. A torsion spring has a first end and a second end. A swing arm has a round hole, a circular hole, and a through aperture. A shaft rod is inserted in the round hole of the swing arm. The shaft rod passes through the torsion spring and the through hole of the frame. An idle wheel engages with the transmission chain. A bearing is adjacent to the idle wheel. The pivot rod is inserted in the circular hole of the swing arm. The pivot rod passes through the ring and the idle wheel. The first end of the torsion spring is inserted in the through aperture of the swing arm. The second end of the torsion spring is hooked on the frame.

Abstract: A vehicle has a transmission shaft having an annular flange, a threaded end, a recess, and a cotter key inserted in the recess. A differential gearing device receives the transmission shaft. The differential gearing device has a bearing cover, a first one-way thrust bearing, a hollow bearing block, a second one-way thrust bearing, and a positioning disk. The hollow bearing block has a plate having four through holes. The first one-way thrust bearing and the second one-way thrust bearing are disposed in the hollow bearing block. Two screws fasten the bearing cover and the hollow bearing block together. A plurality of bolts fasten the plate and a driven element together. The transmission shaft passes through the bearing cover, the first one-way thrust bearing, the hollow bearing block, the second one-way thrust bearing, the positioning disk, and the driven element.

Abstract: An engine has a drive shaft fastening a first sprocket wheel. A transmission gear box is disposed on a vehicle frame. The transmission gear box has a driven shaft fastening a second sprocket wheel. A chain surrounds the first sprocket wheel and the second sprocket wheel. A hexagonal nut is disposed on the driven shaft. A milometer device is disposed on the driven shaft. The drive shaft is disposed on a transmission gear box. A bolt fastens the milometer device and the hexagonal nut together.

Abstract: A transmission mechanism has an outer casing. A hollow tube is connected to a bottom of the outer casing. A main frame has a panel having a round aperture. A shock absorbing assembly has a buffer device, a positioning seat disposed on the buffer device, and a screw rod fastening the positioning seat and the hollow tube together.