Apparatus for grinding the knives in tobacco cutting machines
First Claim
1. In a machine for cutting tobacco and like fibrous materials, a rotary knife holder;
- at least one knife having a cutting edge and being mounted on said holder;
first drive means for rotating said holder about a first axis whereby said cutting edge orbits along a circular first path;
a mobile support;
guide means defining for said support a second path for movement in parallelism with said axis;
a grinding wheel mounted on said support for rotation about a second axis, said wheel having a grinding surface with annular undulations concentrically surrounding said second axis and said surface being adjacent to said first path during movement of said support along said second path;
second drive means for reciprocating said support along said second path in first and second directions between first and second end positions and for moving said support at a speed which is a function of the rotational speed of said holder, at least while said support moves in said first direction, said support assuming said second end position upon completion of movement in said first direction;
first displacing means for shifting the grinding wheel away from said holder when the support reaches or approaches said second end position so that the grinding wheel is out of contact with the cutting edge during movement of the support from the second to the first end position; and
second displacing means for shifting the grinding wheel toward the holder when the support reaches or approaches said second end position so as to move said grinding surface closer to said circular path.
2 Assignments
0 Petitions
Accused Products
Abstract
A tobacco shredding machine wherein the cutting edges of orbiting shredding knives are sharpened by the undulate annular surface of a grinding wheel which is reciprocated forwardly and backwards in parallelism with the axis of the holder for the knives and is retracted from the circular path of the cutting edges during each return stroke of its support. The speed of forward movement of the support while the grinding wheel sharpens the cutting edges is such that the support covers during each revolution of the holder a distance which equals or is a whole multiple of the width of an undulation on the grinding surface. The axes of the grinding wheel and of the holder for the knives are located in a common plane.
18 Citations
20 Claims
-
1. In a machine for cutting tobacco and like fibrous materials, a rotary knife holder;
- at least one knife having a cutting edge and being mounted on said holder;
first drive means for rotating said holder about a first axis whereby said cutting edge orbits along a circular first path;
a mobile support;
guide means defining for said support a second path for movement in parallelism with said axis;
a grinding wheel mounted on said support for rotation about a second axis, said wheel having a grinding surface with annular undulations concentrically surrounding said second axis and said surface being adjacent to said first path during movement of said support along said second path;
second drive means for reciprocating said support along said second path in first and second directions between first and second end positions and for moving said support at a speed which is a function of the rotational speed of said holder, at least while said support moves in said first direction, said support assuming said second end position upon completion of movement in said first direction;
first displacing means for shifting the grinding wheel away from said holder when the support reaches or approaches said second end position so that the grinding wheel is out of contact with the cutting edge during movement of the support from the second to the first end position; and
second displacing means for shifting the grinding wheel toward the holder when the support reaches or approaches said second end position so as to move said grinding surface closer to said circular path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- at least one knife having a cutting edge and being mounted on said holder;
-
17. In a machine for cutting tobacco and like fibrous materials, a rotary knife holder;
- at least one knife having a cutting edge and being mounted on said holder;
first drive means for rotating said holder about a first axis whereby said cutting edge orbits along a circular first path;
a mobile support;
guide means defining for said support a second path for movement in parallelism with said axis;
a carriage;
means for moving said carriage with reference to said support at an angle to said first axis, including a feed screw mounted in said support and a nut movable with said carriage relative to said support and mating with said feed screw;
displacing means for said carriage including cam means adjacent said second path and follower means fixed to said nut and arranged to change the angular position of said nut and hence the position of said carriage relative to said support in response to engagement with said cam means;
a grinding wheel mounted on said carriage for rotation about a second axis, said wheel having a grinding surface with annular undulations concentrically surrounding said second axis and said surface being adjacent to said first path during movement of said support along said second path; and
second drive means for reciprocating said support along said second path in first and second directions and for moving said support at a speed which is a function of the rotational speed of said holder, at least while said support moves in said first direction.
- at least one knife having a cutting edge and being mounted on said holder;
-
18. In a machine for cutting tobacco and like fibrous materials, a rotary knife holder;
- at least one knife having a cutting edge and being mounted on said holder;
first drive means for rotating said holder about a first axis whereby said cutting edge orbits along a circular first path;
a mobile support;
guide means defining for said support a second path for movement in parallelism with said axis;
a carriage;
means for moving said carriage with reference to said support at an angle to said first axis, including a feed screw mounted in said support and a nut movable with said carriage relative to said support and a mating with said feed screw;
displacing means for said carriage including cam means adjacent said second path and follower means turnable with said feed screw relative to said support and said nut to move said carriage relative to said support in response to engagement with said cam means;
a grinding wheel mounted on said carriage for rotation about a second axis, said wheel having a grinding surface with annular undulations concentrically surrounding said second axis and said surface being adjacent to said first path during movement of said support along said second path; and
second drive means for reciprocating said support along said second path in first and second directions and for moving said support at a speed which is a function of the rotational speed of said holder, at least while said support moves in said first direction. - View Dependent Claims (19)
- at least one knife having a cutting edge and being mounted on said holder;
-
20. In a machine for cutting tobacco or like fibrous materials, a rotary knife holder;
- at least one knife having a cutting edge and being mounted on said holder;
first drive means for rotating said holder about a first axis whereby said cutting edge orbits along a circular first path;
a mobile support;
guide means defining for said support a second path for movement in parallelism with said axis;
a grinding wheel mounted on said support for rotation about a second axis which is inclined with reference to said first axis, said wheel having a grinding surface with annular undulations concentrically surrounding said second axis and said surface being adjacent to said first path during movement of said support along said second path, said grinding wheel including a tubular portion having a substantially conical end face which constitutes said grinding surface, said cutting edge being elongated and said grinding surface being in substantially linear contact with said cutting edge once during each revolution of said holder, the region of such linear contact being disposed substantially radially of said grinding surface and that portion of said grinding surface which is in contact with the cutting edge having a component of movement which is substantially tangential to said first path;
second drive means for reciprocating said support along said second path in first and second directions and for moving said support at a speed which is a function of the rotational speed of said holder, at least while said support moves in said first direction, said second drive means being arranged to reciprocate said support along said second path between first and second end positions and said support assuming said second end position upon completion of a movement in said first direction;
first displacing means for shifting the grinding wheel away from said holder when the support reaches or approaches said second end position so that the grinding wheel is out of contact with the cutting edge during movement of the support from the second to the first end position; and
second displacing means for shifting the grinding wheel toward the holder when the support reaches or approaches said first end position so as to move said grinding surface closer to said circular path.
- at least one knife having a cutting edge and being mounted on said holder;
Specification