US2297468A - Sharpening device for the rotating sickle knife of cigarette rod machines - Google Patents

Description

Sept. 29, 1942. P, U E 2,297,468

- SHARPENING DEVICE FOR THE ROTATING SICKLE KNIFE OF CIGARETTE ROD MACHINES Filed May 28, 1940 2 Sheets-Sheet 1 I71 yen for Pa u 2 Louis Gr'zu an cr Sept. 2%, 1942. A P. L. GRAUPNER SHARPENING DEVICE FOR THE ROTATING SICKLE KNIFE OF CIGARETTE ROD MACHINES 2 Sheets-Sheet 2 Filed May 28, 1940 Inventor-z PauZ Loud: GPaUpnCr W Patented Sept. 29, 1942 SHARPENING DEVICE FOR THE vROTATING SICKLE KNIFE OF CIGARETTE ROD MA- CHINES Paul Louis Graupner, Dresden-Radebeul, Germany; vested in the Alien Property Custodian Application May 28, 1940, Serial No. 337,710 In Germany June 3, 1939 4 Claims. (01. 51-247) t This invention relates to a sharpening device for the rotating sickle-shaped knife of cigarette rod machines.

Sharpening devices for the mentioned purpose are known provided with a carrier for the-grinding disc rotating in the same direction as the sickle knife itself, the rotating axis of said carrier being parallel or approximately parallel to the rotating axis of the knife and the grinding disc engaging the cutting edge of the rotating sickle knife during the execution of each rotation. These grinding devices have been satisfactory, however there is still the disadvantage that the so-called face, i. e., the bevelled cutting edge of the generally relatively broad knife does not engage the eounterface of the grinding disc without varying pressure. If the sickle knife which, as known, consists of a thin metal sheet is pressed relatively hard against the grinding disc so that all portions of its face over the whole length of the cutting edge engage the grinding disc, it then necessarily follows that the cutting edge is weakened irregularly by the grinding tool, i. e., one portion of the cutting edge is weakened in a higher degree than another portion so that finally the cutting edge loses its sickle shape and is no longer capable of constantly executing an exact cut. As however the cigarette rod machine operates at an extremely high velocity an exact cut is of the highest importance.

The invention deals with the problem to attain an equal and regular engaging of the cutting edge with the grinding too] even if the knife is extremely broad and engages a corresponding broad face of the grinding tool, and to control the engagement in such a way that the same pressure exists and the wear on the face is equal on all parts of the cutting edge. Further the sickle shape of the knife is maintained.

When solving this problem it is to be considered that the knife is mounted on a carrier rotating about an axis and is arranged obliquely on its carrier in such a manner that the points of the cutting edge following one another during the cut move with the guiding tube of the cigarette rod and execute a screw-like movement to follow the motion of the rod and also of the guiding tube.

In consideration of this circumstance the invention consists therein that a grinding disc having a fiat side face to engage the cutting edge of the sickle knife, is carried by the shaft of a planet-wheel rotating around a stationary sunwheel, the rotating axis of said grinding disc being obliquely adjusted with respect to the axis of the sun-wheel the said axis of the sun wheel being itself obliquely adjusted with respect to the rotating axis of the knife carrier.

In this way the advantage is attained in that the grinding tool executes such a rotating movement and during each rotation the grinding tool engages one time. the cutting edge of the also rotating sickle knife. However due to the mentioned movement of the said both means, the cutting face of thesickle knife is evenly stropped during its passage along the face of the grinding disc without any stronger pressure arising at one portion of the cutting edge than at another.

To attain the greatest possible adjustability it is sufficient to rotatably mount the axis of the sun-wheel around the driving shaft of a bevel gear driving the shaft of the planet-wheel and to arrange. the axis of the sun-wheel obliquely to said driving shaft.

The annexed drawings show one embodiment of the invention by way of example, but many alterations may be made without departing from thespirit of the invention.

Fig. 1 of the drawings is a plan view of a part of a cigarette rod machine showing the drive of the knife and the. grinding device and Fig. 2Jis a side view thereof.

The shaft l of the sickle knife 32 is journalled in two bearings! and 3 fixed to or integral with a block or frame 40 forming a portion of the machine frame. This shaft is obliquely arranged with respect to the guiding tube 4 of the cigarette rod 4!, said guiding tube being fixed to rods 42 which are slidably guided in the machine frame and are reciprocated in a known manner by means of a crank-like device by the main shaft 43 journalled in the block 40.

The block 40 isprovided with a box or bearing 5 carrying a shaft 6. and having a reduced portion 1 around which a shell 8 is provided. This shell may be fixed in any desired position on the reduced portion 1 by means of a screw 9. The shell 8 is provided with a curved projection 10 carrying a bearing l3 in which a shaft I 4 is rotatably mounted. To the one end of the shaft M the bifurcated end l5 of an arm 44 may be clamped in any desired position by means of a screw IS, the opposite end of which arm being provided with a bearing 20 in which a shaft 2| is journalled. Th shaft 2| carries a fiat grinding disc 23 revolving in the direction of the arrow 22.

The drive of the knife and the grinding disc is derived from the main shaft 43 to which the bevel 4 the sun-wheel 30 is arranged, but this sun-M wheel is not fixed to the shaft l4, but to the bearing l3 and is stationary. It is shaped as a spurwheel and meshes with a gear 3| being the planet-wheel fixed to the shaft 2| and provided with oblique teeth.

The axis of the shaft 2| is obliquely arranged with respect to the axis M of the sun-wheel, as shown in Fig. 2 of the drawings. The obliquity of said axis must be so chosen that the resulting movement of the grinding disc 23 corresponds to the movement of the knife in the desired manner, i. e., so that the grinding pressure is constant over the whole length of the cutting edge. The correct obliquity can be easily determined by tests.

When the bevel gear 29 rotates the shaft l4 and the arm 44 with the bearing 26 also rotate. Hereby the planet-wheel 3| runs around the stationary sun-wheel 36 and, rotates with its shaft 2|, the grinding disc 23. The grinding disc in consequence thereof executes a planetary movement around the sun-wheel and at the same time rotates around its axis.

The path of the grinding disc 23 may be adapted to the movement of the sickle knife 32 in consequence of the adjustability provided for.

The movement of the sickle knife 32 with respect to the guiding tube 4 is produced by arranging the axis of the sickle knife obliquely to the axis of the guiding tube 4. Further the carrier 31 of the knife 32 may be obliquely adjusted in a known manner on the block 35 by means of the set screws 34, the block 35 being fastened to the shaft I.

It is to be understood that the face 36 of the knife must be maintained in its regular and correct form when engaging the grinding disc 23. For this purpose the fiat grinding disc 23 must engage the sickle knife always with the same pressure.

When rotating around the axis all points of the cutting edge 36 lie on a face of rotation with respect to the axis Therefore, in consequence of the arrangement and adjustability of the parts, the rotation of the grinding disc 23 may be controlled in such a manner that said grinding disc always engages the cutting edge 36 of the sickle knife 32 with the same pressure during the time in which it contacts with the knife 32.

Therefore the cutting edge is equally groun The knife 32 may be adjusted radially to the axis within its carrier 31, if it is worn out so that the cutting dge 36 may always be retained in its proper position.

I claim:

1. A sharpening device for the revolving sickle knife of cigarette rod machines, comprising, in combination, a revolving carrier, a sickle knife obliquely mounted on said carrier, a second carrier revolving in the same direction of rotation .as the first mentioned carrier, a sharpening tool rotatably mounted on said second carrier and having a flat grinding face adapted to engage the cutting edge of said sickle knife during each revolution of said knife, a shaft rotatably arranged on said second carrier by which said sharpening tool is driven, a planet wheel for said tool, and a stationary sun wheel arranged coaxially with the rotating axis of the said second carrier and engaging said planet wheel, the said shaft being obliquely arranged with respect to the axis of the sun wheel.

2. A sharpening device as claimed in claim 1 in combination with a second shaft mounted at right angles to the rotating axis of the first mentioned carrier, means for driving said second shaft, a third shaft carrying said second carrier, being arranged obliquely with respect to the said second shaft and coaxially with said sun wheel and a bevel gearing connection between said second and third shaft.

3. A sharpening device for the revolving sickle knife of cigarette rod machines, comprising, in combination, a revolving carrier, a sickle knife obliquely mounted on said carrier, a second carrier revolving in the same direction of rotation as the first mentioned carrier, a sharpening tool rotatably mounted on said second carrier and having a fiat grinding face adapted to engage the cutting edge of said sickle knife during each revolution of the knife, a shaft rotatably arranged on said second carrier by Which said sharpening tool is driven, a planet Wheel for the tool, a further shaft on which said second carrier is adjustably mounted, and a stationary sun wheel arranged coaxially with said further shaft and meshing with said planet wheel, the first mentioned shaft being obliquely arranged with respect to the axis of the sun'wheel.

4. A sharpening device as claimed in claim 1 in combination with a second shaft mounted at right angles to the rotating axis of the first mentioned carrier, means for driving said second shaft, a third shaft carrying said second carrier, being arranged obliquely with respect to the said second shaft and coaxially with said sun wheel, a bearing for said third shaft arranged adjustably with respect to the axis of the said second shaft and a bevel gearing connection between said second and third shaft.

PAUL LOUIS GRAUPNER.

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