roller arrangement 314 is assembled between the outer ring 308 and the inner ring 316 for transferring one way rotation the d o w c 302 utilizes a fluid filled piston cylinder 320 which has a mounting end 322 and an interior chamber 324 the mounting end 322 of the fluid filled piston cylinder 320 is connected to the elongated arm 310 of the outer ring 308 an elongated piston rod 330 is assembled with the fluid filled piston cylinder 320 and has a mounting end 332 and a piston 334 at the opposite end the mounting end 332 is connected to the elongated arm 306 of the driving ring 304 the piston 334 is disposed in the interior chamber 324 and biased by a spring 336 and separates the interior chamber 324 into a first fluid chamber 326 and a second fluid chamber 328 a body of fluid 338 is filled into the first and second fluid chambers 326 and 328 again the body of fluid 338 may be a fluid such as water or any other suitable fluid the clearance 19 between the piston 334 and the interior sidewall of the piston cylinder 320 is made deliberately large furthermore a one way valve 346 is built.