1. Field of the Invention
The present invention relates to plastic pelletizing technology, and more particularly to a combination cutter and transmission shaft assembly used in a plastic pelletizing machine for making plastic pellets, which prevents perforated plate damage due to an overpressure.
2. Description of the Related Art
A plastic pelletizing machine for making plastic pellets is known using a motor to rotate a cutter over the surface of a perforated plate to cut off the extruded plastic material into plastic pellets. However, because the cutter is directly and rotatably abutted against the surface of the perforated plate without any buffer, the perforated plate will wear quickly with use.
The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a combination cutter and transmission shaft assembly for plastic pelletizing machine, which prevents an overpressure damage during operation, prolonging the lifespan of the machine.
To achieve this and other objects of the present invention, a combination cutter and transmission shaft assembly of the invention comprises a transmission shaft and a cutter unit. The transmission shaft comprises a tubular shaft body rotatable on the axis thereof and axially movable forward and backward, and a plurality of axial coupling teeth located at a front end of said tubular shaft body. The cutter unit is coupled to and rotatable by the transmission shaft, comprising a cutter holder that comprises an accommodation hole axially defined in one end thereof for receiving the tubular shaft body of the transmission shaft and a plurality of axial coupling grooves axially slidably coupled to the axial coupling teeth of the tubular shaft body, a spring member mounted in the accommodation hole and stopped between an inside wall of the cutter holder and one end of the tubular shaft body of the transmission shaft, and a plurality of cutter blades fastened to one end of the cutter holder remote from the accommodation hole.
Referring to
The transmission shaft 1 comprises a tubular shaft body 11 rotatable on the axis thereof and axially movable forward and backward, and a plurality of axial coupling teeth 12 equiangularly spaced around an outer perimeter of a front end of the tubular shaft body 11.
The cutter unit 2 comprises a cutter holder 21, a spring member 23, a locating member 25, and a plurality of cutter blades 26. The cutter holder 21 comprises an accommodation hole 22 axially disposed in one end thereof, a displacement hole 24 axially disposed in an opposite end thereof in communication with the accommodation hole 22, and a plurality of axial coupling grooves 211 equiangularly spaced around an inner perimeter thereof within the accommodation hole 22 and axially slidably coupled to the axial coupling teeth 12 of the tubular shaft body 11. The spring member 23 is mounted in the accommodation hole 22 and stopped with its one end against an inside wall of the cutter holder 21 between the accommodation hole 22 and the displacement hole 24 and its other end against the front end of the tubular shaft body 11. The locating member 25 is movably mounted in the displacement hole 24 and inserted through the spring member 23 into the tubular shaft body 11 of the transmission shaft 1 in the accommodation hole 22 and affixed to the tubular shaft body 11. The cutter blades 26 are affixed to one end of the locating member 25 outside the cutter holder 21 and rotatable and axially movable with the locating member 25.
The driving mechanism 3 comprises a main drive motor 31, a driving shaft 32, a bearing block 33, and a linear motor 34. The driving shaft 32 is coupled to and rotatable by the motor 31, and axially inserted through the tubular shaft body 11 of the transmission shaft 1. The bearing block 33 is affixed to one end of the tubular shaft body 11 of the transmission shaft 1 and mounted around and rotatable by the driving shaft 32. Thus, the driving shaft 32 can be driven by the main drive motor 31 to rotate the bearing block 33 and the tubular shaft body 11. The linear motor 34 is mounted at one side of the bearing block 33 and controllable to move the bearing block 33 and the tubular shaft body 11 axially forward and backward.
Referring to