Reversing transmission

1. A reversing transmission comprising:

a shaft;

a holder sleeved on the shall with a plurality of spaced sliding notches throughout the wall of the holder and axially extending through an end of the wall;

a spacing collar mounted on an outer circumference surface of the holder at the middle portion;

a plurality of reversing members each comprising two spaced swing plates, wherein each of the swing plates is divided into two regions, one of the regions is formed with a group of spiral teeth, the groups of spiral teeth of the two swing plates are diagonally symmetrically arranged, the extending direction of teeth curves of the two groups of spiral teeth of each reversing member are consistent; and the reversing members are received in the corresponding sliding notches of the holder and the swing plates of each of the reversing members are distributed at opposite sides of the spacing collar;

two gears each being annular shaped and comprising a group of spiral teeth with consistent teeth curves formed on the inner side for engaging with the groups of spiral teeth of the reversing members and cogs formed on the outer surface for engaging with an external toothed member for transmission power; and

two covers mounted on two opposite ends of the holder to keep the reversing members in position;

wherein a switch between the gears is executed when rotation of the shaft is reversed, and during the switch, currently engaged ones of the swing plates gradually descend relative to the shaft to drive an engaged one of the gears apart from the spacing collar until the engaged swing plates disengage from the engaged gear, meanwhile, non-engaged ones of the swing plates gradually elevate relative to the shaft to engage with the spiral teeth of a non-engaged one of the gears via the groups of spiral teeth of the non-engaged swing plates.

2. The reversing transmission of claim 1 , wherein the shaft defines a plurality of uniformly spaced grooves on its outer surface along a direction parallel to the center axis thereof; and each of the reversing members comprises a semicircle cross-section roller interconnecting the two swing plates at two opposite ends and received in one of the grooves of the shaft.

3. The reversing transmission of claim 2 , wherein each of the grooves is semilunar shaped with a curve shaped bottom supporting the semicircle cross-section roller.

4. The reversing transmission of claim 2 , wherein the holder comprises an annular base, a plurality of camber plates, and a plurality of bars; the camber plates are evenly distributed on a lateral surface of the annular base; the sliding notches are defined between every pair of adjacent camber plates; the bars are evenly distributed on the lateral surface of the annular base and received in the sliding notches; and the bars and the camber plates are alternatively arranged.

5. The reversing transmission of claim 4 , wherein each of the swing plates is arciform shaped and comprises a concave surface fixed with the roller and a convex surface opposite to the concave surface; each of the bars comprises an arcuate inner surface and an opposite curved outer surface; and the convex surfaces of the swing plates resist on the arcuate inner surfaces of the bars.

6. The reversing transmission of claim 5 , wherein the lateral surfaces of each camber plate are designed as smoothly recessed shapes corresponding to the arcuate inner surfaces of the adjacent bars.

7. The reversing transmission of claim 5 , wherein the group of spiral teeth of each swing plate is formed on the convex surface beside the roller; and the two groups of spiral teeth of the two swing plates of each reversing member are arranged on two sides of the axis of the roller correspondingly.

8. The reversing transmission of claim 5 , wherein the group of spiral teeth of each swing plate is formed on the convex surface beside the roller; and the two groups of spiral teeth of the two swing plates of each reversing member are diagonally arranged.

9. The reversing transmission of claim 5 , wherein a plurality of gaps is defined between the bars and the adjacent camber plates; and the swing plates of each reversing member are accommodated in one of the sliding notches with the two groups of spiral teeth exposed from the gaps.

10. The reversing transmission of claim 5 , wherein each of the covers comprises a circle plate and a flange protruding from the annular periphery of the cover; the circle plate defines a shaft hole at the center for the shaft to pass through, and a plurality of threaded holes; and the threaded holes surround the shaft hole and correspond to the threaded holes defined on an end of the holder for allowing bolts to pass through to fix the cover to the retainer.

11. The reversing transmission of claim 10 , wherein a gap between the flange and the spacing collar is large enough for the corresponding gear to move therein without any interference.