Double shaft breaker

Abstract: A double shaft breaker for use in breaking plastic wastes and wastes of metal cans so that the materials can be used again. The double shaft breaker comprises: two driving shafts (13, 14) supported rotatably in parallel with each other in apparatus frames, a plurality of shredding large cutters (15, 16) fixed to each of said driving shafts with a prescribed interval between the shredding large cutters, said shredding large cutters on the right and left being opposed to each other or being apart from each other, the rotational angle of said shredding large cutters on the right being the same as that of said shredding large cutters on the left or said shredding large cutters on the right being meshed with said shredding large cutters on the left, or the sides of the shredding large cutters on the right being slidably engaged with the sides of said shredding large cutters on the left, a plurality of breaking small cutters (17, 18) fixed between the shredding large cutters with a prescribed interval between the shredding small cutters, stationary blades (19) located between the pair of the breaking small cutters, a pair of guide plates (20, 21) located between said shredding large cutters and the apparatus frame, drop preventive covers (22) located along the rotational radius of said pair of shredding large cutters, and a driving apparatus (25-29) for rotating the driving shafts in such directions that objects to be broken may be broken by the edges of said breaking small cutters and the edges of the stationary blades.

Description: Field of the invention The present invention relates to a breaker, and more particularly to a double shaft breaker for use in breaking plastic wastes and metal can wastes so that the materials can be used again. Description of Prior Art Generally, in order to reuse plastic wastes, it is well known to break the plastic wastes into pellets and to mix the pellets with virgin pellets. An example of such a conventional breaker for breaking plastic wastes into pellets is disclosed in Japanese Utility Model Gazette 61-3461 (1986) to the present inventor issued on February 3, 1986. The constitution of the breaker for plastic wastes disclosed therein is described with reference to Fig. 3. A driving shaft 2 is supported horizontally in an apparatus frame 1 and rough breaking blades 3 and fine breaking blades 4 are secured to the driving shaft 2, with the driving shaft 2 through the blades 3 and 4. One stationary comb blades is opposed to the rough breaking blades 3 and the fine breaking blades 4 at a position where resin molded articles will be broken, and a receiving plate 6 for scraping resin molded articles adhered to the blades is opposed to the rough breaking blades 3 and the fine breaking blades 4 in the symmetrical position in relation to the stationary comb blade 5. A receiver 7 for preventing broken pieces resulted from the rough breaking by the rough breaking blades 3 from dropping outside the apparatus frame is located in a position surrounding approximately the lower half of the rough breaking blades 3. In this prior art single-shaft-driven breaker, however, since the rough breaking blades 3 and the fine breaking blades 4 attached to the driving shaft 2 are opposed to the one stationary comb blade 5, there is only a difference in the relative speed upon the passage of the rough breaking blades 3 and the fine braking blades 4 through the stationary comb blade 5. Consequently, there is a defect that when objects are broken, the objects tumble about in the apparatus frame thereby resulting in failure of the breaking or that if broken pieces adhere to the stationary comb blade 5 and the adhered broken pieces take shapes corresponding to the shapes of the rough braking blades 3 and the fine breaking blade 4, the breaking power is no longer exhibited. Double shaft breakers are known per se. E.g. DE-C-72294 describes a meat mincing meachine comprising two parallel driving shafts each carrying a plurality of rotating large cutter blades intended to cutting the material and transporting and pressing it to Y-shaped stationary blades located below the space between the driving shafts. The minced meat drops down from the blades, comb strippers preventing that any material adheres to the rotating blades. The construction of this mince meat machine is not suitable for shredding hard materials such as plastic and metal sheet wastes. Summary of the Invention The object of the present invention is to provide a double shaft breaker for use in breaking plastic wastes and wastes of metal cans so that the materials can be used again. A double shaft breaker according to the present invention, comprising: two driving shafts supported rotatably in parallel with each other in apparatus frames; fixed to each of the driving shafts, a plurality of shredding large cutters at some axial distance from each other; stationary blades located in the area between the driving shafts; a pair of guide plates located between the shredding large cutters and the apparatus frame; and a driving apparats for rotating the driving shafts in such directions that objects in the breaker may be broken, partly by the edges of the stationary blades, is characterized in that in the axial intervals between the large shredding cutters, a plurality of breaking small cutters are fixed to each of the driving shafts with prescribed distances therebetween; that the stationary blades are located between the sets of breaking small cutters of the one and the other driving shaft so that the objects may be broken by the edges of the driven breaking small cutters and the edges of the stationary blades; and that below the shredding large cutters approximately along the rotational circumference thereof, drop preventing covers are located. In the thus constituted double shaft breaker, the opposing shredding large cutters and breaking small cutters of the driving shafts are rotated in opposite directions in relation to each other with the rotational speeds of the shredding large cutters and the breaking small cutters being the same of different. Out of objects to be broken which are charged into the apparatus frames, larger ones are dragged in and broken by the shredding large cutters. The thus broken objects are further broken by the opposing breaking small cutters in cooperation with the central stationary blades. Accordingly the present invention has an excellent breaking effect without defects associated with the prior art single shaft shredding large cutters and breaking small cutters, for example, defects that objects to be broken tumble about in the apparatus frame and are not broken when they are to be broken and that objects to be broken adhere to the stationary comb blade and take shapes corresponding to the shapes of the rough breaking blades and the fine breaking blades and therefore the breaking power is no longer exhibited. Brief Description of the Drawings Fig. 1 is a plan view of a double shaft breaker illustrating an embodiment according to the present invention. Fig. 2 is a cross-sectional view taken along line A-A of Fig. 1. Fig. 3 is a cross-sectional view illustrating a prior art breaker. Description of Preferred Embodiment An embodiment of the present invention is described with reference to Figs. 1 and 2. Two driving shafts 13 and 14 which are parallel to each other are rotatably supported in apparatus frames 11 and 12. A plurality of shredding large cutters 15 and 16 are fixed to the driving shafts 13 and 14. In this case, the shredding large cutters 15 and 16 are fixed to the driving shafts 13 and 14 with the shredding large cutters 15 opposed to the shredding large cutters 16 and with a prescribed interval between the shredding large cutters 15 (16). Alternatively, the shredding large cutters 15 and 16 may be fixed to the driving shafts 13 and 14 with the side of shredding large cutters 15 slidably engageable with the side of the shredding large cutters 16 or with the shredding large cutters 15 apart from the shredding large cutters 16. Herein, the rotational angle of the shredding large cutters 15 and the rotational angle of the shredding large cutters 16 are the same or are made such that the shredding large cutters 15 may mesh with the shredding large cutters 16. Breaking small cutters 17 (18) are fixed between the shredding large cutters 15 (16), with a prescribed interval between the breaking small cutters 17 (18). Stationary blades 19 are fixed to the apparatus frame 11 between the pair of the breaking small cutters 17 and 18 and a pair of guide plates 20 and 21 are placed between the shredding large cutters 15 and 16 and the apparatus frame 12. The apparatus frame 12 is provided with drop preventive covers 22 along the rotational radius of the shredding large cutters 15 and 16. The driving shafts 13 and 14 are rotated by a driving apparatus so that objects to be broken may be broken by the edges of said breaking small cutters 17 and 18 and the edges of the stationary blades. In this driving apparatus, gears 23 and 24 are fixed to one end of the driving shafts 13 and 14 and are meshed with each other. Herein, the number of teeth of the gear 24 and the number of the teeth of the gear 23 may be selected to the same or different. The other end of the driving shaft 13 is provided with a chain wheel 25 which is in turn through a chain 28 associated with a chain wheel 27 of a reduction gear-equipped motor 26 fixed to the apparatus frame 11. The chain 28 is made taut by a tensioner 29. When the driving shaft 13 and the chain gear 25 in association with the chain gear 27 through the chain 28 are rotated by driving the reduction gear-equipped motor 26, the gears 23 and 24 rotate the driving shaft 14 in the direction opposite to that of the rotation of the driving shaft 13. Therefore, the pair of the shredding large cutters 15 and 16 are rotated with their rotational frequencies being the same or different and with the rotational angles of them being the same or with them meshed with each other. Larger ones out of the objects to be broken such as plastic wastes and metal cans charged into the apparatus frame 12 are dragged and broken roughly by the shredding large cutters 15 and 16. The broken objects are moved back to the apparatus frame 12 by the dropping-preventive covers 22 arranged below the shred guide plates 20 and 21 and are broken by the breaking small cutters 17 and 18 arranged in line with the shredding large cutters 15 and 16. Since the drop preventive covers 22 are located below the shredding large cutters, 15 and 16, only the objects broken by the breaking small cutters 17 and 18 drop out of the apparatus frames 11 and 12; i.e., since the preventive covers 22 are located below each of the large cutters only, but the objects broken by the shredding small cutters 17 and 18 drop out of the apparatus frames 11 and 12 through the intervals between the preventive covers 22.

Claims: A double shaft breaker, comprising: two driving shafts (13,14) supported rotatably in parallel with each other in apparatus frames (11,12); fixed to each of the driving shafts (13,14), a plurality of shredding large cutters (15,16) at some axial distance from each other; stationary blades (19) located in the area between the driving shafts (13,14); a pair of guide plates (20,21) located between the shredding large cutters (15,16) and the apparatus frame (12); and a driving apparatus (25-29) for rotating the driving shafts (13,14) in such directions that objects in the breaker may be broken, partly by the edges of the stationary blades (19); characterized in that in the axial intervals between the large shredding cutters (15,16), a plurality of breaking small cutters (17,18) are fixed to each of the driving shafts (13,14) with prescribed distances therebetween; that the stationary blades (19) are located between the sets of breaking small cutters (17,18) of the one and the other driving shaft (13, 14) so that the objects may be broken by the edges of the driven breaking small cutters (17, 18) and the edges of the stationary blades (19); and that below the shredding large cutters (15,16) approximately along the rotational circumference thereof, drop preventing covers (22) are located. A double shaft breaker according to claim 1, characterized in that the plurality of shredding large cutters (15,16) are located at the driving shafts (13,14) so that on the right and left, they oppose each other. A double shaft breaker according to claim 1 or 2, characterized in that the plurality the shredding large cutters (15,16) are located at the driving shafts (13,14) so that those on the right are axially offset from those on the left. A double shaft breaker according to any of claims 1 to 3, characterized in that the rotational angle of the plurality of the shredding large cutters (15) on the right is the same as that of the plurality of the shredding large cutters (16) on the left. A double shaft breaker according to any of claims 1 to 4, characterized in that the rotational angles of the plurality of the shredding large cutters (15, 16) are such that the shredding large cutters on the right are meshed with the shredding large cutters on the left.

Inventors: NAKAGOMI SHOJI, NAKAGOMI, SHOJI
Applicants: NAKAGOMI SHOJI, NAKAGOMI, SHOJI
Application year: 1992
Main classification: B02C18
IPC codes: B02C18