Abstract: A wiper blade wipes over a predetermined range of a front windshield in response to rotation of a wiper motor in a forward and reverse directions. The wiper blade operates in a wiping range between a predetermined upper reversing position and a predetermined lower reversing position. An upper pre-reversing position is defined inside of the upper reversing position, and a lower pre-reversing position is defined inside of the lower reversing position. A rotation sensor produces pulse signals in response to the rotation of the wiper motor. A CPU counts the pulse signals produced from the rotation sensor when a position detection sensor detects an arrival of the wiper blade at the pre-reversing position. The CPU produces a control signal to a drive circuit and reverses the direction of the drive current of the wiper motor to reverse the rotation of the wiper motor, when the pulse count value reaches a predetermined value.

Abstract: A motor device having a hollow casing in which a mechanism for converting continuous rotational motion of a rotating member into reversible rotational motion to transmit the converted motion to an output shaft. This motor device includes an oscillation member which oscillates around the output shaft. Further, it includes a driving force conversion member which is interposed between the oscillating member and the rotating member, and which converts the continuous rotational motion of the rotating member into reciprocating oscillatory motion of the oscillating member. This driving force conversion member includes a contacting portion which projects toward an inner wall of the hollow casing and which is formed integrally with the driving force conversion member. This contacting portion slides on the inner wall of the hollow casing over the range of displacement of the driving force conversion member, and moreover is formed from a material which is capable of absorbing sound generated by sliding motion.

Abstract: A windshield wiper device including a blade rubber, a backing holding the blade rubber in place, a support metal fixture including support claws for supporting the backing, an arm supporting the metal fixture, a spring loading the arm such that the blade rubber is forced against the windshield of a vehicle, and drive means connected to the arm for moving the arm, the metal fixture, the backing and the blade rubber in oscillating movement. The spacing interval between the adjacent two support claws is maximized at opposite end portions of the blade rubber and becomes smaller in going toward the center thereof, and a higher load is applied to the support claws near the central portion of the blade rubber than to the support claws near the opposite ends thereof, to thereby effectively avoid separation of the blade rubber from the surface of the windshield.

Abstract: This improved method comprises a first dry step of reacting concentrated sulfuric acid and potassium sulfate with potassium chloride at about 300.degree. C. in a slurried state to obtain a mixed slurried salts of K.sub.n H.sub.2-n SO.sub.4 (n being 1.3 to 1.4); a second wet step of dissolving said mixed salts and additional raw potassium chloride in water, the amount of water being limited to some extent, heating the solution to 60.degree. to 90.degree. C. in order to take place a wet reaction, and cooling the solution to 50.degree. to 20.degree. C. to deposit potassium sulfate crystals from the solution in order to obtain the final product and filtrate; and a third circulating step of evaporating the filtrate to obtain a cake of mixed salts of acid potassium sulfate and potassium chloride, and returning circulatingly the cake to the first stage as part of raw materials.