GB2066649A

GB2066649A - Controlled tobacco cutter

Info

Publication number: GB2066649A
Application number: GB8037950A
Authority: GB
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1979-11-27
Filing date: 1980-11-26
Publication date: 1981-07-15
Also published as: GB2066649B; DE2947689A1

Abstract

A tobacco cutter comprises a cutting drum, a presser conveyor for compressing and feeding to the cutting drum at known rate tobacco removed from a storage container, and a means for detecting and indicating the cut width of the cut tobacco and making such process adjustments as are desired. <IMAGE>

Description

SPECIFICATION Tobacco cutter The invention relates to a tobacco cutter having a cutting drum and a presser conveyor for compres sing and feeding to the cutting drum the tobacco removed from a storage container.

Generally tobacco cutters consist of a storage containerforthe uncut tobacco, a pressure conveyor and a cutting drum the periphery of which is fitted with cutting blades extending in the direction of the axis. The presser conveyor consists of presser chains which supply the tobacco from the storage containertothe cutting drum and at the same time compress the tobacco to a tobacco cake. The drive of the tobacco cutter is so designed that the speed of rotation of the cutting drum and the feed speed of the presser conveyor are in a fixed mutual ratio by which the cutting width of the tobacco is also predetermined. In this case the adjustment of the cutting width is effected generally on the basis of empirically derived values by changing the speed of the presser conveyor relative to the speed of the cutting drum.It is impossible in this case to monitor the cut width, which is a disadvantage in particular when the cutting widths must be altered frequently.

The present invention has for its object the provision of a tobacco cutter in which permanent monitoring and rapid adjustment of the cut width of the cut tobacco is possible. For successive processing of dif ferenttypes of tobacco with different nominal cutting widths, reliable monitoring of the correct adjustment of the cutting widths associated with particulartobacco types is to be ensured.

This problem is solved in a tobacco cutter of the kind referred to above in accordance with the invention by a device for detecting and indicating the cut width of the cut tobacco. Thus the cut width of the cut tobacco may be read off and controlled at any time at the indicator provided for this purpose.

Because of this indicator an extremely accurate adjustment of the cut width of the tobacco is possible.

The tobacco cutter according to the invention comprises measuring means for detecting the feed speed v, of the presser conveyor, measuring means for detecting the rotary speed vr of the cutting drum, and an evaluation circuit. The evaluation circuit comprises an arrangement for forming a quantity Gp which is proportional to the feed speed vp, an arrangement for forming a quantity GT which is proportional to the drum speed VT, and an arrangement for forming the quotient GT/Gp. The evaluation circuit is connected to an arrangement for indicating the quotient GT/Gp which constitutes a measure for the cut width of the cut tobacco.

It is particularly advantageous to detect digitally the feed speed vp of the presser conveyor and the rotary speed VT of the cutting drum. For this purpose the presser conveyor is equipped with one or more initiators which produce pulses at time intervals corresponding to the feed speed vp, and the cutting drum is equipped with one or more initiators which produce pulses at time intervals corresponding to the rotary speed VT. These initiators are connected to counting modules which count the clock pulses delivered between two successive pulses of the initiators by a higher frequency clock pulse generator and deliver them as a measure for the length of the time intervals elapsed between the successive pulses of the initiators to a storage member connected therebeyond.At the output end the stores are connected to digital-analogue converters for forming quantities Gp proportional to the feed speed vp or quantities GT proportional to the rotary speed VT of the cutting drum, respectively. The output of the digital-analogue converters is connected to a divider module as arrangement for forming the quotient GT/Gp. The digitally detected measuring quantities are thus converted to analogue quantities and as such manipulated further to an indication.

In the first place inductive capacitative, electromechanical or electro-optical pulse transmitters come into consideration as initiators. According to the invention the arrangement for forming the quotient GT/Gp is constructed in the form of a divider module and the input thereof is connected to the outputs of the storage members.

At a very high operational speed of the tobacco cutter the time intervals elapsing between two pulses produced by the initiators at the presser conveyor become shorter so that the counting pulses of a first predetermined clock pulse frequency fl issued by the clock pulse generator are no longer suitable to determine with sufficient accuracy the time duration of these intervals. The voltage at the output of the subsequent digital-analogue converter depends upon the number of the run-up counting pulses and becomes too small. For this case it is provided that the evaluation circuit comprises a change-over switch by which the clock pulse generator is frequency switchable dependently upon the feed speed vp andlorthe speed of rotation VT.

Preferably a digital indicator is employed as indicating device for the quotient GT/Gp. In the first place a digital voltmeter is provided as such indicator.

A possibility for the automatic control of the cutting width of the tobacco cutter is provided by the invention by the fact that according to a further constructional form of the invention the indicated measuring value may be fed as actual value to a control arrangement for controlling the cutting width of the tobacco.

Since uninterrupted monitoring of the cut width of the tobacco does not appear to be necessary in every case, an embodiment of the invention provides that the evaluation circuit is designed for the connection and the selection of a plurality of tobacco cutters.

Thus the cutting width control for a plurality of tobacco cutters is effected by means of a single apparatus. In this case the evaluation circuit comprises change-over switches for adjusting the number of the cutters on each cutting drum. Advan tageouslythese change-over switches are connected to a multiplication amplifier connected beyond the arrangement for forming the quotient GT/Gp. The indication appearing in the indicator display therefore takes into account also the respective number of cutters arranged on the cutting drum of the respec tive tobacco cutter.

The particular advantage of the tobacco cutter proposed in accordance with the invention resides in that for the first time a direct control of the cut width of the cuttobacco is rendered possible. Thereby the conversion of the tobacco/cutter to the manipulation of varying sorts of tobacco is simplified in a mean ingful manner. Moreover the construction of the evaluation circuit in the manner proposed according to the invention permits the very rational employment of this evaluation circuit for indicating the cutting widths of a plurality of tobacco cutters which can be connected simultaneously to this evaluation circuit. All that is necessary forthis purpose is that the corresponding initiators are attached to the presser conveyors and the cutting drums of the respective tobacco cutters and connected to the evaluation circuit.The cutting widths of the individual tobacco cutters may then be read out twill.

The invention will now be further described by way of example only, with reference to the accompanying drawings, in which: Fig. lisa diagrammatic cross-section of one embodiment of a tobacco cutter according to the invention; Fig. 2 is a block diagram of a circuit for detecting and indicating the cutting width of the tobacco; and Fig. 3 is a block circuit diagram of a preferred constructional form of the evaluation circuit In Fig. 1 the tobacco cutter is generally denoted by 1. It is erected on a pedestal 2 which supports a casing 3 of the tobacco cutter. The storage container for the uncut tobacco is constructed as an accumulation shaft4to which the uncut tobacco is supplied at the top. The accumulation shaft 4 terminates downstream in the entry region of a presser conveyor 6 which is formed by a lower presser chain 7 and an upper presser chain 8.The presser chains 7 and 8 converge towards a mouthpiece 9 at which is positioned a cutting drum 11. The tobacco removed from the accumulation shaft 4 is compressed by the presser chains to form a tobacco cake during the conveyance to the mouthpiece or the cutting drum, respectively; the tobacco cake issues from the mouthpiece 9 towards the cutting drum 11 and is cut by cutters 12 arranged in the axial direction on the periphery of the cutting drum 11. The cut tobacco falls down and is conveyed away for further processing. The cutters are re-ground continuously by means of a honing device 13.

For driving the presser conveyor 6 a motor 14 is provided the torque of which is transmitted to the driving shafts of the presser conveyor 6 by means of an adjustable gear (PIV-) gear 16, chain drives 17 and 18, as well as a gearwheel drive 19. The motor 14 is so coupled to the drive (not illustrated for reasons of clarity) of the cutting drum 11 that the speed of rotation of the cutting drum and the feed speed of the presser conveyor 6 are always in a predetermined mutual ratio. This speed ratio of the speed of rotation of the cutting drum and the feed speed of the presser conveyor determines the cutting width of the cut tobacco.

Now, according to the invention it is provided that the tobacco cutter is equipped with a device for detecting and indicating the cut width of the cut tobacco. For this purpose the driving wheel of the upper presser chain 8 is provided in the illustrated case with an initiator 21 which delivers pulses to the evaluation circuit 22 in correspondence with the feud speed of the presser conveyor 6. The spacing of two successive pulses of the initator is proportional to the feed speed vp of the presser conveyor 6. For the purpose of detecting the speed of rotation VT ofthe cuttingdrumll the latter is equipped with an initiator 23 which is likewise connected to the evaluation circuit 22. The evaluation circuit 22 processes the pulses produced by the initiators 21 and 23 to form a cutting width indication which appears in the display 24.This display 24 is arranged on a control unit 26 which in the case illustrated is supported by a pivotal bracket 27 for facilitating operation. The control unit 26 is fitted with switches 28 for adjusting the cutting width.

The manner of operation of the tobacco cutter illustrated in Fig. 1 is as follows: The uncut tobacco travels from the accumulation shaft 4 into the entry region of the presser conveyor 6 and initially it is conveyed by the lower presser chain 7 towards the mouthpiece 9. During the further conveyance it is compressed between the lower presser chain 7 and the upper presser chain 8 and supplied to the mouthpiece 9. At the same time the feed speed of the presser conveyor 6 is detected by means of the initiator 21 arranged atthe driving wheel of the upper presser chain 8 and is supplied to the evaluation circuit 22 as a succession of pulses.

The tobacco cake issuing from the mouthpiece 9 is cut by means of the cutting drum 11, the speed of rotation of the cutting drum being detected by means of the initiator 23. The succession of pulses corresponding to this speed of rotation is also transmitted to the evaluation circuit 22 which converts the pulses from the initiator 23 and the pulses from the initiator 21 to a cutting width indication which appears in the display 24. Thus the display 24 always indicates the actual value of the cut width of the cut tobacco. If this cut width differs from the predetermined value, the speed of the presser conveyor 6 may be adjusted by adjusting the variable gear 16 by means of the operating elements 28 in such a manner that the desired value of the cut width appears in the display 24.

Fig. 2 is a circuit diagram illustrating the principle of the cut width indication proposed in accordance with the invention 1 again denotes the tobacco cutter of which only the component parts are illustrated which are of interest in the present context. The cut tingdrum T1 and the presser conveyor of which only the upper presser chain 8 is illustrated are driven here by a common motor 14, the upper presser chain 8being preceded by a variable gear 16.

The pulses 29 produced by the initiator 23 in the pulse transmitter 23' and the pulses 31 produced by the initiator 21 in the pulse transmitter 21' travel by way of the associated connections and the changeover switch 32 to the logic circuit 33 of the evaluation circuit 22. The latter processes the pulse sequence in the manner proposed according to the invention to form an indication 24 of the cut width of the cut tobacco.

- Fig. 2 illustrates an embodiment in which the evaluation circuit is designed for the connection of six tobacco cutters. For this purpose the evaluation 'circuit 22 is provided with a corresponding number of inputs 34 and 36 to which, in the case illustrated, the initiators of six tobacco cutters can be connected.

The respective desired tobacco cutter is coupled to the evaluation circuit 22 by means of the change over switch 32.

Since the cutting drums of the six tobacco cutters connected thereto may have a different number of cutters a change-over switch 37 is provided by means of which the appropriate number of cutters can be adjusted for each tobacco cutter. Correspond ing to the number of connections six contact groups 37 are provided of which, however, only two, the uppermost and lowermost contact group, are illus trated in Fig. 2. Since apart from the speed of rota tion of the cutting drum 11 the cut width of the tobacco depends also upon the cutters 12 present on the periphery of the said drum, the change-over switch 37 ensures that the number of cutters is taken into account, as required, for the determination of the cutting width.

In Fig. 3 which contains a block circuit diagram of the evaluation circuit, solely the upper presser chain 8 and the cutting drum 11 of the tobacco cutter 1 are illustrated. The evaluation circuit comprises two branches one of which is provided for processing the pulses 29 delivered by the cutting drum 11 and the other one of which is provided for processing the pulses 31 delivered by the upper presser chain 8. The first branch provided for processing the pulses 29 comprises a counter 38 the output of which is con nected to a divider module 42 by way of a store 39 and a digital-analogue converter 41. The second branch of the evaluation circuit which is provided for processing the pulses 31 contains likewise a counter 43 which is connected to the divider module 42 by way of a store 44 and a digital-analogue converter 46.Additionally the counters 38 and 43 are in con nection with a frequency divider 48 which is loaded by the clock pulse generator 47 and which is designed for delivering counting pulses of the lower frequency f1 and the higher frequency f2. The output of the divider module 42 is connected to the indi cator display 24 by way of an amplifier 49.

The output of the digital-analogue converter 46 is connected to a comparator 52 the output of which is connected to a switching device 53. This switching device 53 actuates a frequency change-over switch 56 by way of a connection 54. The terminals 57 are provided for the connection of an automatic control (not illustrated) of the cutting width of the tobacco cutter.

The mode of operation of the circuit illustrated in Fig. 3 is as follows: By the rotation of the cutting drum 11 pulses 29 are produced the time interval tT between which cor responds to the rotary speed of the cutting drum 11.

These pulses travel to the input of the counter 38 and to the store 39. Every pulse 29 arriving in the counter 38 sets this counter to zero and starts it. The counter 38 starts then to count the clock pulses delivered at a known constant frequency f1 by the frequency divider 48, until the next following pulse stops the counting process. The frequency f1 of the clock pulses is higher than that of the measuring pulses 29, so that a large number of clock pulses is counted in the counter 38 in the interval of time between two pulses 29. This number of clock pulses from the frequency divider 48 counted by the counter 38 is therefore a measure of the chronological spacing tT of two successive pulses 29. The next following pulse 29 cancels the store 39 and is effective at the same time as a transfer signal which effects the transfer of the content of the counter 38 to the store 39.Simultaneously the counter 38 is re-set to zero, so that a fresh count may start. The content of the store 39 is then converted to an analogue quantity GT in the digitalanalogue converter 41 which quantity is proportional to the speed of rotation VT of the cutting drum.

This quantity GT travels to the divider module 42.

The processing of the pulses 31 arriving from the upper presser chain 8 occurs in the same manner. In the time interval tp between two pulses 31 clock pulses from the frequency divider 48 are counted into the counter43 at the known constant frequency f1. Upon the arrival of the next following pulse 31 the counter content is transferred to the store 44 the content of which had previously been cancelled by the corresponding pulse 31. Simultaneously the counter 43 is re-set to zero and started afresh. The store content travels to the digital-analogue converter 46 where it is converted to a quantity Gp proportional to the feed speed,. This value travels likewise to the divider module 42.

The quotient GT/Gp is formed in the divider module 42 and guided by way of the multiplication amplifier 49 to the indicator display 24. In the amplifier 49 the value arriving from the divider module 42 is multiplied by a constant factorthe magnitude of which depends upon the number of cutter blades arranged on the cutting drum; the number of cutters can be adjusted at the change-over switch 37. The indicator 24 indicates then directly the cutting width of the tobacco cutter.

A rotary range of approximately 1:50 must be detected by sensing the feed speed of the upper presser chain 8. At higher rotary speeds, i.e. at a higher feed speed, the time interval tp between two pulses 31 becomes so short that an accurate measurement is no longer possible by means of the frequency f1 from the frequency divider 48, since the frequencyf1 is too low. In ordertocounterthis defect, the quantity Gyp which is produced in the digital-analogue converter 46 and which is proportional to the feed speed vp is compared with a threshold value in a comparator 52. If the quantity GP falls below a predetermined value a signal is produced which actuates the switching device 53.

Thereby the frequency change-over switch 56 is switched from the frequency f1 to a higher frequency f2 of the frequency divider 48, so that an accurate count of the time interval tp is rendered possible.

Thus the evaluation circuit may be rendered suitable even for large speed changes of the presser conveyor in an automatic manner.

A signal for automatically controlling the cutting width of the tobacco cutter may be taken off the ter minals 57.

Claims

1. Atobacco cutter comprising a cutting drum, a presser conveyor for compressing and feeding to the cutting drum tobacco removed from a storage container, and a means for detecting and indicating the cut width of the cut tobacco.

2. Atobacco cutter as claimed in claim 1, wherein the means for detecting and indicating the cut width of the cut tobacco comprises measuring means for detecting the feed speed vp of the presser conveyor, measuring means for detecting the rotary speed vet of the cutting drum, and an evaluation circuit including an arrangement for forming a quantity Gwhich is proportional to the feed speed vp, an arrangement for forming a quantity GT which is proportional to the drum speed VT, and an arrangement for forming the quotient GT/Gp, and connected with an arrangement for indicating the quotient GT/Gp as a measure for the cut width of the cut tobacco.

3. A tobacco cutter as claimed in claim 1 or 2, wherein the presser conveyor is equipped with one or more initiators which produce pulses at time intervals which correspond to the feed speed vp for digitally detecting the feed speed vp and the cutting drum is equipped with one or more initiators which produce pulses at time intervals which correspond to the rotary speed vet for digitally detecting the rot ary speed VT.

4. Atobacco cutter as claimed in claim 3, wherein the initiators are connected to counting modules which count the clock pulses delivered between two successive pulses of the initiators by a higherfre- quency clock pulse generator and deliver them, as a measure of the length of the time intervals elapsing between two successive pulses of the initiators, to a storage member connected therebeyond, the output ends of the storage members are connected to digital-analogue converters for forming respectively quantities Gyp which are proportional to the feed speed vp or quantities GT which are proportional to the rotary speed VT of the cutting drum, and the digital-analogue converters are connected to a divider module for forming the quotient GT/Gp.

5. Atobacco cutter as claimed in claim 3 or 4, wherein inductive, capacitative, electro-mechanical or electro-optical pulse transmitters are provided as initiators.

6. Atobacco cutter as claimed in any one of claims 1 to 5, wherein the arrangement for forming the quotient GYGp is constructed in the form of a divider module and its input end is connected to the storage members.

7. Atobacco cutter as claimed in any one of claims 1 to 6, wherein the evaluation circuit com prises a change-over switch for setting the number of the cutters on the cutting drum and the said switch is connected to a multiplication amplifier which is connected beyond the arrangement for forming the quotient GT/Gp.

8. Atobacco cutter as claimed in any one of the claims 1 to 7, wherein the clock pulse generator has a frequency switching facility for changing the clock pulse frequency dependently upon the feed speed Vp.

9. Atobacco cutter according to any one of - claims 1 to 8, wherein the clock pulse generator has a frequency switching facility for changing the clock pulse frequency dependently upon the rotary speed VT of the cutting drum.

10. Atobacco cutter according to any one of claims 1 to 9, wherein the evaluation circuit is designed for the connection and the selection of a plurality of tobacco cutters

11. Atobacco cutter according to any one of claims 1 to 10, wherein a digital indicator is used as indicating device forthe quotient GT/Gp.

12. Atobacco cutter as claimed in claim 11, wherein a digital voltmeter is employed as indicating device for the quotient GT/Gp.

13. Atobacco cutter as claimed in any one of claims 1 to 12, wherein the indicated measuring value is fed to a control arrangement for controlling the cutting width of the tobacco, as an actual value.

14. A tobacco cutter as claimed in any one of claims 1 to 13, further comprising an adjusting device for pre-setting a nominal value of the cutting width.

15. Atobacco cutter, substantially as herein described with reference to and as illustrated in the accompanying drawings.