US3908817A

US3908817A - Dispensing of particulate material

Info

Publication number: US3908817A
Application number: US420126A
Authority: US
Inventors: Richard Ernest Gartsid Neville; Frank Baxter Bardsley
Original assignee: AMF Inc
Current assignee: AMF Inc
Priority date: 1972-12-07
Filing date: 1973-11-29
Publication date: 1975-09-30
Anticipated expiration: 1992-09-30
Also published as: DE2360416A1; GB1418016A; FR2209519B1; CA987563A; DE2360416C2; FR2209519A1

Abstract

A tobacco feeding device comprising a passage formed by a series of sections consecutively decreasing in cross-sectional area with means at each section for advancing the tobacco along the passage towards the low cross-sectional area end thereof.

Description

United States Patent Neville et a1.

[4 1 Sept. 30, 1975 DISPENSING OF PARTICULATE MATERIAL lnventors: Richard Ernest Gartside Neville,

Salisbury; Frank Baxter Bardsley, Newton Toney, near Salisbury, all

of England Assignee: AMF Incorporated, White Plains,

Filed: Nov. 29, 1973 Appl. No.: 420,126

Foreign Application Priority Data Dec. 7, 1972 United Kingdom 56623/72 US. Cl 198/76; 198/223 Int. Cl. 365g 37/00 Field of Search 222/190; 198/76, 212, 218, 198/221, 223, 224, 210

[56] References Cited UNITED STATES PATENTS 2,305,904 12/1942 Selvig 198/76 2,454.831 11/1948 Nordquist 198/210 Primary Etanziner-Robert B. Reeves Assistant E.\'anzinerHadd Lane Attorney, Agent, or F irmGeorge W. Price; Charles .1. Worth 57 ABSTRACT A tobacco feeding device comprising a passage formed by a series of sections consecutively decreasing in cross-sectional area with means at each section for advancing the tobacco along the passage towards the low cross-sectional area end thereof.

17 Claims, 9 Drawing Figures US. Patent Sept. 30,1975 Sheet 1 of8 3,908,817

US. Patent Sept. 30,1975 shw 2 of8 3,908,817

US. Patent Sept. 30,1975 Sheet 3 of8 3,908,817

US. Patent Sept. 30,1975 Sheet4 0f8 3,908,817

Sheet 5 0f 8 3,908,817

US. Patent Sept. 30,1975

Sheet 6 of 8 US. Patent Sept. 30,1975 Sheet 7 of 8 3,908,817

DISPENSING OF PARTICULATE MATERIAL This invention concerns a machine for automatically dispensing small constant-weight portions of hand rolling or pipe tobacco for subsequent packing. In particular, the narrow stream feeder for preparing the tobacco in a form from which the initial portion can be dispensed with accuracy.

In known apparatus initial portions are dispensed by methods depending on volume, pressure and weight.

In one method a constant volume is dispensed by cutting a stream at regular intervals or filling a constant volume and then cutting or parting the stream. The portion is then weighed and make-up material added to correct the weight. In a refinement of this method a constant volume device is filled to a fixed pressure and the stream then cut.

In another method the portions are dispensed by feeding a small cross-section stream of material onto a weighing conveyor or pan and parting or cutting the stream when the desired under-weight has been achieved.

In all methods the initial portion is aimed at a smaller weight than that finally required and a correction is carried out by adding smaller pieces or fines previously separated from the tobacco bulk. This follows from the matted nature of the material which makes it easier to add rather than deduct small corrections and also accounts for the need to cut or part the stream to produce the portions.

The efficiency of the dispenser is measured by the closeness of the initial portion to the final weight required and hence the smallness of the correction to be made.

The efficiency of the dispenser, whichever method is used is dependent on the uniformity of the narrow cross-section stream fed to the dispenser.

The efficiency of the narrow stream feeder, in fact the success of the whole machine, ismeasured by'the uniformity of the stream it produces and especially by the extent to which it does not degrade or disintegrate the tobacco in the process of producing the uniform narrow stream.

A particular problem arises with tobacco due to the non-grandular or non-fluid nature of the material coupled with the small amount to be separated, typically 0.5 to 2.0 ounces.

The tobacco used for hand rolling consists of fine shreds cut from tobacco leaf typically at 100 cuts per inch. These shreds are of variable length but generally several inches long and form individual cohesive masses or cobs of entwined and matted shreds which do not easily separate, mixed with a minority of successive gradations of smaller particles or fines which will separate. The moisture content is typically 25 per cent and the un-compressed bulk density typically 8 lbs/ft for small depths rising to 16 lbs/ft for depths of 2 ft. The cobs are of variable size but typically around 0.1

ft weighing llb.

It is the object of the invention to enable the tobacco to be separated into very much smaller portions of acor fleece of l to 4 ins cross-section and 1 /2 to 6 02. weight per foot length is convenient.

Hand rolling tobacco with the matted shred form described above will, by its nature, only form a uniform stream of very much larger cross-sections.

One method of achieving the narrow stream is to divide the mass of cut tobacco into its individual shreds by means of successive carding drums and then reforming a stream or fleece to the size required. This is the method used in a cigarette making machine for forming the cigarette rod.

However, in cigarette tobacco the shreds are coarser, typically 50 cuts/inch and shorter typically 0.75 inch long so the amount of breaking -or shortening of the strands termed degradation is less than with the hand rolling tobacco and acceptable. I

With hand rolling tobacco the customer handles the tobacco himself and the length of the strands is a standard of quality which determines how readily the hand rolled cigarette holds together. It is, therefore, desirable to maintain the length of the strands in hand rolling tobacco and the amount of degradation resulting from the above method is unacceptable.

Another method of producing a small cross-section stream or fleece of tobacco is to reform a much larger stream by drawing it out to the smaller crosssection. This method most nearly matches the manual method used at present in which an operating position is fed with a large cross-section stream of tobacco in a-- A further object of the present invention is to providea machine to achieve this second method in which a readily formed large cross-section slow moving stream of finely cut tobacco is drawn out and accelerated into a small cross-section faster moving stream of the same density.

According to the invention we provide a tobacco feeding device comprising a passage forme'd'by a series of sections decreasing consecutively in cross-sectional area and means at each section for advancing the tobacco along said passage towards the low crosssectional area end thereof, said means having projections which enter the tobacco during advance and which effect a drawing out of the tobacco in the direc tion of advance at each section. In this manner the tobacco is substantially noncompressed as it passes through the passage.

The invention will be further described by way of example with reference to the accompanying diagram-' matic drawings, wherein:

FIGS. 1, 2 and 3 are respectively a front elevation, side elevation and plan of a machine made in accordance with the invention,

FIG. 4 is a section on the plane IV-IV on FIG. 1,

FIGS. 5 and 6 are an elevational view and plan of one of the feeding units,

FIGS. 7 and 8 are an elevational view'and plan of one of an alternative form of feeding unit, and

FIG. 9 is a section on the line IX'IX of FIG. 7.

Referring to FIGS. 1, 2 and 3, the machine comprises a vertical converging passage defined by a feed tube 10,

a number of feeding unit assemblies 11, 11' and a discharge conveyor tube 13. The passage finally converges to a cross-section of for example 1.25 X 1.25 inch which can be more or less if desired.

In the embodiment shown, feeding unit assemblies are arranged at six levels or stations (I-VI), the units of each level being offset by 90 relative to the units of each adjacent level. More or less levels may be provided.

Each

feeding unit assembly

11, 11 consists of one or more feeding units 12 each of which comprises a pair of parallel side plates 14 separated from each other by spacers 16 and a front plate 17 which faces the interior of the converging passage. (See FIGS. and 6). The front plate 17 houses a pair of rockers or guide

members

19, 20 mounted for oscillation about a common spindle 22 and having arcuate surfaces facing the passage. Rocker 19 has a pin 24 passing therethrough which pin is carried at one end of a pin plunger arm 25. The other end of the pin plunger arm 25 is mounted on a crank pin 27 of a gear wheel 28. Similarly, the rocker 20 has a pin 30 passing therethrough, the pin plunger arm 31 of which is mounted on a crank pin 33 of another gear wheel 34. Each

pin plunger arm

25, 31 is mounted on the respective crank

27, 33 by way of a bearing 36, 37.

A drive shaft 40, common to the assembly, enters the unit 12 through one side plate 14 and carries a pair of drive pinions 41, 42 which respectively engage

gear wheels

28, 34.

Each station or level includes an approximately square or rectangular throat. Two sides of the throat are formed by the pairs of oscillating

rockers

19, 20 and the other two sides are formed by retaining plates 43 which provide continuity with the next station and with the discharge conveyor tube 13.

The pins are arranged in pairs which are spaced apart from each other and pairs of pins in the succeeding station are located between the planes of the preceding pairs.

It can be seen that the pin plunger arm 25 is considerably shorter than the arm 31 and that the

driving gear wheels

28 and 34 have their centres offset from one another. Furthermore, the crank pins 27, 33 are angularly offset from each other by approximately 45.

The feeding unit 12 operates as follows:

Rotation of the drive shaft results in the rotation of

gear wheels

28, 34 which carry the

pin plunger arms

25, 31. As the

gear wheels

28, 34 are rotated, the pin plunger arms advance the pins successively and by reason of the pivoting rockers are caused to carry out a downward swing. As each pin ends its advancing movement, it withdraws into its rocker and remains retracted while the rocker effects a return movement whereupon with the commencement of the downward movement of the rocker, the pin emerges therefrom. The action is the same for each pin except that due to the difference in length of the pin plunger arms and the relative position of the

gear wheels

28, 34, the stroke and extent of penetration differ.

Therefore, the pairs of cooperating oscillating pins have the same frequency but differing amplitudes, i.e. strokes and penetrations. The longer stroke pin 24 has a shorter penetration than the short stroke pin 30 and leads it by approximately phase angle. Both pins progress the tobacco down the convergent passage but with the differential pin action the long stroke pin 24 tries to progress it more than the short stroke pin with the result that the matted tobacco is drawn out in the axial direction of the passage by the long stroke pin 24 whilst being partially held back by the short stroke pin 30. The tobacco is therefore not compressed at any one station but is drawn out at the same time as being re duced in cross sectional area.

The tips of the

pins

24, 30 thus move over paths such as those shown in FIG. 4, the tips of the pins sweeping in close proximity to the arcuate surfaces of the opposed rockers at the lower levels. As shown in FIG. 4, at each level of the converging passage feeding units are arranged in pairs on opposite sides of the channel. At level I, four pairs of feeding units 12 are provided, while at levels II, III, IV, V and VI respectively three, three, two, two, and one pair of units are provided. The pins may also be progressively shorter, of smaller diameter and have less stroke.

The crank wheels may be arranged to operate the pins of any one level so that they follow each other in desired succession. The pins of level I for example enter the tobacco and as these commence retracting the pins of level II are still advancing followed in succession by the pins of levels III, IV, V and VI, each group being a sixth of a cycle out of phase with the preceding group. Hence a more or less continuous drive is imparted to the tobacco.

The pins at each level move in a plane at right angles to the pins of adjacent levels.

The driving speed of the pins at successive levels is increased approximately in inverse proportion to the reduction in crosssectional area of the channel so that a constant tobacco density is maintained. At the lower levels however the pins move even faster. The throat sizes of the six levels of the example shown are respectively 37, 25, 12, 6, 3 and L5 square inches. The speed of rotation of the successive groups of pins are typically 1, 3, 7, 22, and 200 rpm respectively.

It will be evident from FIG. 4 that the

rockers

19, 20 at a given level constitute a converging zone X at that level, and between the converging zone there are regions Y where the walls of the channel are substantially parallel. In these regions or cushioning zones, the pulses set up in the tobacco by the pins are smoothed out and low frequency pulses from upper levels are prevented from passing to lower levels. To avoid any side friction within each cushioning zone Y the parallel side walls thereof are stepped out M inch all round from the point of maximum convergence directly above the zone. Although the whole aim of each level of feeding is to converge the tobacco by about 2:1 without compressing it, in practice there is some slight temporary compression of the tobacco, which would result in side friction and jamming if not allowed room to re-expand.

The shafts 40 of the first, second, third, fourth, fifth and sixth stations are all driven from a motor 47., through a variable gearbox 48, various chains 49 and sprockets 50 and right angle gearboxes 51. The right angle gearboxes 51 may be replaced by a flexible drive if desired. Dog clutches 52 finally connect the drive to the shafts 40.

The motor 47 and gearbox 48 are mounted on a main frame 53 (FIG. 3) to which are pivoted two subframes, 54, 54 which carry the feeding unit assemblies 11' while the feeding unit assemblies 11 are secured to the main frame 53. Drive to the assemblies 11' includes universal joints 56, which enable the units 11 to be swung away from the converging channel tofas slist cleaning etc. All the assemblies 11 "ofs'tations'l', lll and V are mounted on a common subframe 54 while assemblies ll of stations II, [V and VI are also mounted on a common sub-frame The main frame'53 and;

sub-frames

54,54 are not's'hown in FIGS. and 2for the aid of simplicity. Y

The sixth station may be followed by a short two band conveyor as shown in FIGS 1 and'2. This conveyor is formed by a pair of plates 55 disposed parallel to each other and secured to belt guides56, also parallel to each other, said plates and guides forining an" tnsioning means i maintain a constant density of tobacco feed to a volume dispensing device. If required, a reduction or in-" crease in density can be achieved by altering the speeds disproportionately. This method is used to control the density of the stream fed to the constant volume or constant volume and pressure type dispenser. The machine may feed via a constant volume dispenser followed by a weigher or a constant volume and pressure dispenser with a cutter followed by a weigher or to a weighing conveyor or pan with a cutter. The tobacco then feeds to a weight correction point receiving fines from the fines separator, check weigher, rejection and acceptance unit to supply the final product.

It has been found in practice that the stroke of the short stroke pin in the direction of the axis of the passage is preferably very short compared with the long stroke pin whilst the penetration of the pin into the tobacco in a direction at right angles to the axis is the same for both pins.

To achieve this short stroke but deep penetration with the simple crank mechanism shown in FIGS. 5 and 6 requires the gear wheel 34 to be moved further away from gear wheel 28 and the pin plunger arm 31 to be extended. This results in a pin unit of cumbersome dimensions, but the embodiment shown in FIGS. 7, 8 and 9 has been found to overcome this.

Referring to the embodiment shown in FIGS. 7, 8 and 9 in which like reference numerals relate to thelike features in relation to the above described embodiment, a feeding unit 12 comprises a pair of side plates .14 separated from each other by spacers l6 and a front :plate 17 which faces the interior of the converging passage. The front plate 17 houses a pair of rockers or guide

members

19, 20 mounted for oscillation about a common spindle 22 and having arcuate surfaces facing the passage. Rocker 19 has a pin 24 passing therethrough which pin is carried at one end of a pin plunger arm 25. The other end of the pin plunger arm 25 is mounted on a crank pin 27 of a gear wheel 28. How- .ever, the pin plunger arm 31 of the pin 30 which passes through the rocker 20 is differently mounted. The pin plunger arm 31 is carried on a crank pin 60 of a planet gear 61 which in turn is carried on a crank pin .62 of gear wheel 63. The planet gear 61 engages with a ring gear 64 having exactly double the number of teeth as the planet gear 61.

40; enters the J unit 112 through one side plate and, carries a drive pinion .65 which engagesboth gear wheels63 and 28. Thus,-the prank 6 0 carrying the pinj plunger arm 31] is .driven'in an elliptic all ste d of circular path,

thereby reducing the stroke of pin 30. 7

It is found, ,using the above described device-that a hopper of Q0, lbpercub ic. foot results in an output having a density of 12 lb per cubic foot. That is, the density remains. substantially; unaltered considering that the cross sectional area is reduced 24 fold (37 squareinches to l.5 square inches).

A particular. advantageof the oscillating pins com pared withpaddles or pin drums is that the pinsare selfcleaningas they are withdrawn and that there are no slots or,holes in the totally enclosed convergent passage to collect tobacco and :cause -.jamming.' 4

We claim: 1. A. cut tobacco-feeding device,comprising,a passage formed bya series of sections decreasing consecutively in cross-sectional area and means at ,each section for,

advancing the tobacco along said passage towards the low cross-sectional area end thereof; each of said means having forward and. rearward oscillating projections which enter the tobacco during advance with said forward projection moving faster and having a longer stroke than said rearward projection to effect a drawing out of the tobacco in the direction of advance at each section.

2. A tobacco feeding device as claimed in claim 1, wherein said means comprise pins arranged in closely adjacent pairs, and drive means for moving each pin in such a manner that the free end thereof enters the passage during movement thereof in the advance direction and withdraws in the opposite direction of movement, the relative distance between the two free ends of the pair of pins increasing during movement in the advance direction.

3. A tobacco feeding device as claimed in claim 2, wherein the free ends of the two pins 'are caused to move along paths of different lengths at the same frequency, one pin moving faster than the other in the advance direction portion of the pathsf 4. A tobacco feeding device as claimed in claim 3, wherein one of said pins of each pair enters the passage in advance of the other pin of said pair.

5. A tobacco feeding device as claimed in claim 4, wherein the leading pin is the faster moving pin.

6. A tobacco feeding device as claimed in claim 2, in which each pair of pins extending into the passage is opposed by another pair of pins extending into the passage from the opposite side thereof.

7. A tobacco feeding device as claimed in claim 2, further comprisinga drive unit for each pair of pins, said drive unit comprising for each pin, a wheel, means for rotating said wheel, a crank pin on said wheel secured to said pin or a member attached thereto, and a guide member free to oscillate about a fixed point and through which said pin passes.

8. A tobacco feeding device as claimed in claim 2, further comprising a drive unit for each pair of pins, said drive unit for one pin comprising a wheel, means for rotating said wheel, a crank pin on said wheel secured to said pin'or a member attached thereto and a guide member free to oscillate about a fixed point and through which said one pin passes, while for the other pin said drive unit further comprises a wheel, means for rotating said wheel, a crank pin on said wheel carrying a planet gear, a gear ring engaging said planet gear and having twice as many teeth as said planet gear, a crank pin on said planet gear secured to said other pin or a member attached thereto, and a guide member free to oscillate about said fixed point-and through which said other pin passes.

9. A tobacco feeding device as claimed in claim 7, in which the two wheels of each drive unit are driven from a common drive shaft.

10. A tobacco feeding device as claimed in claim 1, in which the passage comprises a plurality of converging zones in which the walls of the passage converge and in each of which said projections comprise pins which extend into said passage, said converging zones being separated from one another by a plurality of cushioning zones in which the walls of the passage do not converge and in which no-pins extend into said passage.

11. A tobacco feeding device as claimed in claim 10, in which the pins of one converging zone extend into the passage at right angles to the pins of each adjacent converging zone.

12. A tobacco feeding device as claimed in claim 11, in which the cross-sectional area of each cushioning zone is slightly greater than the minimum crosssectional area of the immediately preceding converging zone.

13. A tobacco feeding device as claimed in claim 12,

r in which said frequency of movement of the free ends of the pins of each converging zone is greater than the corresponding frequency in the immediately preceding converging zone.

14. A tobacco feeding device as claimed in claim 13, in which the number of pairs of pins of each converging zone is equal to or less than the number of pairs of pins of the immediately preceding converging zone.

15. A tobacco feeding device as claimed in claim 14, in which at the large cross-sectional end of the passage, means are provided for feeding tobacco to the passage.

16. A tobacco feeding device as claimed in claim 15, in which at the low cross-sectional end of the passage, means are provided for discharging tobacco therefrom.

17. A tobacco feeding device as claimed in claim 16, in which the discharge means comprise a pair of conveyor belts on opposite sides of the passage and means for driving said belts in a direction to cause tobacco in the passage to be discharged therefrom.

Claims

1. A cut tobacco feeding device comprising a passage formed by a series of sections decreasing consecutively in cross-sectional area and means at each section for advancing the tobacco along said passage towards the low cross-sectional area end thereof, each of said means having forward and rearward oscillating projections which enter the tobacco during advance with said forward projection moving faster and having a longer stroke than said rearward projection to effect a drawing out of the tobacco in the direction of advance at each section.

3. A tobacco feeding device as claimed in clAim 2, wherein the free ends of the two pins are caused to move along paths of different lengths at the same frequency, one pin moving faster than the other in the advance direction portion of the paths.

4. A tobacco feeding device as claimed in claim 3, wherein one of said pins of each pair enters the passage in advance of the other pin of said pair.

7. A tobacco feeding device as claimed in claim 2, further comprising a drive unit for each pair of pins, said drive unit comprising for each pin, a wheel, means for rotating said wheel, a crank pin on said wheel secured to said pin or a member attached thereto, and a guide member free to oscillate about a fixed point and through which said pin passes.

8. A tobacco feeding device as claimed in claim 2, further comprising a drive unit for each pair of pins, said drive unit for one pin comprising a wheel, means for rotating said wheel, a crank pin on said wheel secured to said pin or a member attached thereto and a guide member free to oscillate about a fixed point and through which said one pin passes, while for the other pin said drive unit further comprises a wheel, means for rotating said wheel, a crank pin on said wheel carrying a planet gear, a gear ring engaging said planet gear and having twice as many teeth as said planet gear, a crank pin on said planet gear secured to said other pin or a member attached thereto, and a guide member free to oscillate about said fixed point and through which said other pin passes.

10. A tobacco feeding device as claimed in claim 1, in which the passage comprises a plurality of converging zones in which the walls of the passage converge and in each of which said projections comprise pins which extend into said passage, said converging zones being separated from one another by a plurality of cushioning zones in which the walls of the passage do not converge and in which no pins extend into said passage.

12. A tobacco feeding device as claimed in claim 11, in which the cross-sectional area of each cushioning zone is slightly greater than the minimum cross-sectional area of the immediately preceding converging zone.

13. A tobacco feeding device as claimed in claim 12, in which said frequency of movement of the free ends of the pins of each converging zone is greater than the corresponding frequency in the immediately preceding converging zone.