Solid material comminution or disintegration – Processes – Miscellaneous
Reexamination Certificate
2001-05-03
2003-10-21
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Processes
Miscellaneous
C241S037000, C241S101200, C241S223000, C241S242000, C083S174000, C451S072000
Reexamination Certificate
active
06634579
ABSTRACT:
CROSS-REFERENCE TO RELATED CASES
This application claims the priority of the commonly owned copending German patent application Serial No. 100 21 614.5 filed May 4, 2000. The disclosure of such German patent application, as well as that of each US and/or foreign patent and patent application identified in the specification of the present application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The invention relates to improvements in methods of and in apparatus for sharpening one or more knives which is or are mounted on a rotary knife holder. More particularly, the invention relates to improvements in methods and apparatus which can be resorted to with advantage for automatic adjustment and sharpening of orbiting knives of the type employed in the tobacco processing industry to convert a continuous body (often called cake) of compacted fragments of tobacco leaves into a flow of shreds which are assembled into a so-called filler, namely into a continuous rod-shaped body which is ready to be draped into a continuous cigarette paper web or the like.
Certain presently known apparatus which are utilized to shred compacted fragments of tobacco leaves into shapes ready to be fed into a cigarette rod making machine (e.g., a machine known as PROTOS) are distributed by the assignee of the present application); such apparatus include those which are known all over the world as KT 2 cutters (also distributed by the assignee of the present application). The apparatus and the method of the present invention can be put to use by resorting to and in KT 2 cutters.
German patent No. 29 21 665 discloses a tobacco cutter (shredder) wherein a rotary holder carries at least one adjustable knife which orbits about a fixed axis and the cutting edge of which is sharpened by a grinding tool. The knife or knives are adjustable relative to the holder in order to compensate for wear attributable to repeated severing of a mass of compacted tobacco particles as well as to removal of knife material by the grinding implement.
The patented cutter employs a step-down transmission which serves to couple the drive for the knife holder with the knife adjusting system. The arrangement is such that the rate at which the knife or knives is or are shifted relative to the holder is determined by the step-down transmission. In order to change the speed of knife feed, one must manually adjust the operative connection between the step-down transmission and the knife or knives.
OBJECTS OF THE INVENTION
An object of the instant invention is to provide a novel and improved method of automatically compensating for wear upon one or more knives which are orbited by a rotary knife holder and undergo wear as a result of (a) repeated engagement with the commodity (such as the leader of a continuous cake or flow or mass of compacted fragments of tobacco leaves) and (b) repeated or continuous removal of knife material by one or more grinding and/or other knife sharpening implements.
Another object of the invention is to provide a method which can be practiced in connection with existing cutters, such as the aforementioned KT 2 cutter.
A further object of this invention is to provide a method which ensures that the rate of material removal from and the rate of adjustment of the knife or knives are selected in dependency upon all, or upon all important or relevant, parameters which influence the wear upon the knife or knives, e.g., in a tobacco shredding machine.
An additional object of the invention is to provide a novel and improved cutter or the type wherein a rotary holder carries one or more knives which orbit about the axis of the holder and undergo wear as a result of repeated contact with the material being severed (such as compacted tobacco leaves which must be shredded prior to admission into a cigarette making machine) and as a result of repeated sharpening by one or more grinding, honing and/or other material removing instrumentalities.
Still another object of the invention is to provide the above outlined cutter with novel and improved means for rendering the removal of material from and the feeding of the knife or knives dependent upon one or more important parameters which are disregarded in presently known cutters.
A further object of the invention is to provide a novel and improved automatic control system for the parts which influence the wear-dependent adjustments of the knife or knives in a tobacco shredding machine.
Another object of the invention is to provide a novel and improved method of evaluating and utilizing signals which are indicative of variable parameters of the material to be comminuted and/or of the comminuting machine.
An additional object of the invention is to provide a tobacco shredding machine wherein the knife or knives is or are sharpened only when a sharpening is necessary or advisable and only to the extent to restore the quality of the knife or knives to a desired or optimum value.
A further object of the present invention is to provide a novel and improved tobacco shredding apparatus which can carry out all of the above-enumerated novel functions and operations even though it can employ readily available standard monitoring, driving, motion transmitting and other components.
SUMMARY OF THE INVENTION
One feature of the present invention resides in the provision of a method of sharpening at least one knife which orbits along an endless path about a predetermined axis and the sharpening of which necessitates an adjustment relative to at least one sharpening tool (such as a grinding wheel) which is adjacent the path of orbital movement of the at least one knife. The improved method comprises the steps of monitoring the magnitude of torque which is required to orbit the at least one knife about the predetermined axis at a predetermined (desired or prescribed) speed, and adjusting the at least one knife relative to the at least one sharpening tool in response to departures of the magnitude of monitored torque from a predetermined range of acceptable magnitudes (this range can embrace a single acceptable magnitude or a plurality of such magnitudes).
The method can further comprise the steps of monitoring at least one of a plurality of additional parameters (i.e., parameters other than the aforediscussed torque) which influence the sharpness of the at least one knife, comparing the at least one additional parameter with a range of acceptable additional parameters, and adjusting the at least one knife relative to the at least one sharpening tool when the monitored at least one additional parameter is outside of the range of acceptable additional parameters. This method can be resorted to for automatically sharpening at least one knife which is utilized to repeatedly sever the leader of an advancing mass of compacted tobacco particles. The additional parameters can include the cross-sectional area of the leader of the advancing mass (i.e., the quantity of tobacco per unit length of the mass), the moisture content of the mass, the storage time of tobacco particles in the mass (this might exert some influence upon the moisture content of tobacco), the nature of treatment or treatments of tobacco particles prior to severing, the quantity of tobacco in the leader of the mass (this can depend upon the degree or extent of compacting of tobacco forming the mass), the homogeneousness (or lack of homogeneousness) of the mass, the percentage of comminuted tobacco leaves in the mass (as compared with the percentage of comminuted tobacco ribs, artificial tobacco or substitute tobacco), the brand or brands of tobacco in the mass, the temperature of the mass, the percentage and/or the size and/or the composition of foreign matter in the mass, the speed of advancement of the mass, and the extent of contaminatin of the at least one knife.
The monitoring step can include continuously monitoring the magnitude of torque which is required to orbit the at least one knife.
The method can further include the step of comparing the magnitude of monitored torque with the aforementioned range of acceptab
Anderson Chad C.
Hauni Maschinenbau AG
Kinberg Robert
Rosenbaum Mark
Venable LLP
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