Please select the most similar patent number from A, B, C and D. Which number is?
A bidirectional transmission device for a bicycle, which comprises a large sprocket, a frame, an extended circular chain, a small sprocket I, a small sprocket II, a guide wheel, a ratchet device I and a ratchet device II, wherein the large sprocket rotates around a shaft on the frame, a segment of the extended circular chain is connected to the large sprocket and the top of the small sprocket I, a segment thereof is connected to the bottom of the large sprocket and the top of the small sprocket II, bypasses the small sprocket I and the small sprocket II and then is connected to the guide wheel, respectively, when the large sprocket rotates clockwise, it drives the small sprocket I to rotate clockwise, and the small sprocket I drives a rear wheel shaft to rotate forward through the ratchet device I, at the moment, the small sprocket II rotates counterclockwise and the ratchet device II rotates idly, when the large sprocket rotates counterclockwise, it drives the small sprocket II to rotate clockwise, and the small sprocket II drives the rear wheel shaft to rotate clockwise through the ratchet device, at the moment, the small sprocket I rotates counterclockwise and the ratchet device rotates idly, so that the rear wheel shaft rotates in one direction all the time.
A: Disclosed is a rotary trash-cleaning machine having an electric motor not prone to damage. Annular tracks are arranged on two sides of a machine frame; an annular chain is arranged in each annular track; the top of each annular track is provided with an opening; a driving shaft is arranged at the opening; two gears are arranged on the driving shaft; collection shafts are arranged on the annular chain; and a drive assembly for driving the driving shaft to rotate is arranged at one end of the driving shaft. The drive assembly comprises a driven chain wheel located on the driving shaft, and an electric motor located on the machine frame, wherein a driving chain wheel is arranged on an output shaft of the electric motor; the driven chain wheel and the driving chain wheel are connected by means of a conveying chain; the output shaft of the electric motor and the driving chain wheel are connected by means of a connecting sleeve, and the connecting sleeve comprises a circular sleeve and a flange plate located at one end of the circular sleeve; and the driving chain wheel is connected to the flange plate by means of a shear pin. In the present utility model, a shear connection is added between the output shaft of the electric motor and the driving chain wheel, such that when the electric motor is overloaded, the shear pin cannot bear an output torque of the electric motor, the shear pin is broken, the driving chain wheel does not rotate any more, and the rotary trash-cleaning machine stops running.
B: Provided is a manual hoist (1), comprising: a manual chain wheel (2), a manual chain (3) borne on the manual chain wheel (2) and used for driving the manual chain wheel (2), and a gear shaft (4) driven by the manual chain wheel (2). The manual hoist (1) further comprises: a first load-lifting chain wheel (5) sheathed on the gear shaft (4) and rotating synchronously with the gear shaft (4); a gear set having a driving gear (6) and a driven gear (7), the driving gear (6) being sheathed on the gear shaft (4) and rotating synchronously with the gear shaft (4), and the driven gear (7) driving the rotation of a driving shaft (8); a second load-lifting chain wheel (9) sheathed on the driving shaft (8) and rotating synchronously with the driving shaft (8); an endless load-lifting chain (10) which passes around the first load-lifting chain wheel (5) in a clockwise or counter-clockwise winding direction with a buffer section (11) being left, and then passes around the second load-lifting chain wheel (9) in a winding direction opposite to the first load-lifting chain wheel (5) with a load-bearing section (12) being left, and then goes back to the first load-lifting chain wheel (5). The present manual hoist significantly increases the speed at which heavy goods are lifted, and is especially suitable for use with heavy goods requiring long-distance lifting, thereby improving load-lifting efficiency of the manual hoist.
C: Disclosed is a reverse clutch device for a bi-directionally driven bike, which device comprises a sprocket shift controller (1), an outer sprocket assembly (2) and an inner sprocket assembly (3). The sprocket shift controller comprises a four-linkage mechanism composed of a supporting frame (11), a pulling bar (12), a shifting plate (13) and a connecting plate (14) hinged successively to each other at the back of the bike tube, with the supporting frame mounted on the tube of the bike. The outer sprocket assembly is fixed on a middle shaft (4b), and a pin assembly (21) is provided on the outer sprocket assembly. The inner sprocket assembly is sheathed on the middle shaft, and is arranged parallel to the outer sprocket assembly, the inner sprocket assembly being provided with a shifting ring (7) connected to the shifting plate; a spring (5) is sheathed on the middle shaft and is located between the inner sprocket assembly and a five-way piece (4c) of the bike; the inner sprocket assembly is provided with a pin hole (31) at the position corresponding to the pin assembly; and the sides of the inner sprocket assembly and the outer sprocket assembly facing each other are respectively provided with a magnet block (6a) and an iron block (6b). By means of operating a handle (16) to move the pulling bar, the inner sprocket assembly moves along the middle shaft, inserting or disengaging the pin assembly into/from the pin hole.
D: Provided are a driving device (2) suitable for a hand strap (1) at the lower end of escalator and an escalator, wherein the driving device (2) comprises a transition sprocket (11), a minor sprocket (14) arranged on a step sprocket (15) and a drive sprocket (9) arranged on a rotating wheel (16) at the end of a handrail, the transition sprocket (11), the minor sprocket (14) and the drive sprocket (9) are positioned on the same side of the escalator, a first drive chain (10) is arranged between the transition sprocket (11) and the drive sprocket (9), a second drive chain (12) is arranged between the transition sprocket (11) and the minor sprocket (14). The structural design of the driving device (2) is reasonable, and does not require extra power source, the driving device (2) is powered by the rotating step sprocket (15), the hand strap (1) has good synchronism and low fault rate.
Answer: C