US3769990A

US3769990A - Apparatus for treating a fleece of fibrous material

Info

Publication number: US3769990A
Authority: US
Inventors: H Williams
Original assignee: Imperial Tobacco Group Ltd
Current assignee: Imperial Tobacco Group Ltd
Priority date: 1971-02-08
Filing date: 1972-01-17
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06
Also published as: ZA72291B; NL7201407A; DE2202513A1; AU3794572A; BE778686A; GB1347263A

Abstract

Apparatus for separating successive leading portions of tobacco rag from a fleece thereof on a horizontal imperforate conveyor wherein a separator device, which comprises two forks facing one another across the conveyor which are retractable together and are relatively separable in the direction of the conveyor to tear a leading portion away from the fleece, is arranged to operate above the conveyor and is movable around a circular path in a vertical plane, the forks being retracted together prior to their descending entry into the fleece.

Description

United States Patent 1191 Williams 1111 3,769,990 1 1 Nov. 6, 1973 1 APPARATUS FOR TREATING A FLEECE 0F FIBROUS MATERIAL [75] Inventor: Hugh Charles Williams, Bristol,

England [73] Assignee: imperial Tobacco Group Limited, I London, England [22] Filed: Jan. 17, 1972 [21] Appl. No.: 218,375

[30] Foreign Application Priority Data Feb. 8, 1971 Great Britain 4,141/71 521 u.s.c1 131/81, 131/108, 131/38, j, 131/40, 225/93, 209/1 51 int. A24c 1/02 581 Field of Search 225/93, 100; 198/34; 131/146, 108, 110, 38, 40, 41', 45, 21 c, 81;

[56] 9 References Cited UNITED STATES PATENTS 1,977,994 10/1934 Lindblad..- 131/81 R X 2,840,129 6/1958 Jovis 225/93 X 1,303,855 5/1919 131/81 R 2,775,969 l/1957 131/81 R X 2,747,580 5/1956 Neumair 131/81 R X Primary ExaminerAndrew R. .luhasz Assistant ExaminerJames F. Coan Att0rneyLarson, Taylor & Hinds [57] ABSTRACT Apparatus for separating successive leading portions of tobacco rag from a fleece thereof on a horizontal imperforate conveyor wherein a separator device, which comprises two forksfacing one another across the conveyor which are retractable together and are relatively separable in the direction of the conveyor to tear a leading portion away from the fleece, is arranged to op erate above the conveyor and is movable around a circular path in a vertical plane, the forks being retracted together prior to their descending entry into the fleece.

7 Claims, 5 Drawing Figures PATENTEDRUV ems SHEET 2 OF 3 This invention relates to apparatus for treating a FIG. 1 is a vertical longitudinal section through apparatus for treating a fleece of fibrous material on a 'belt conveyor,

FIG. 2 is, on a larger scale, an end view of the apparafleece or web of fibrous material and more particularly ms Showing a Separator device and P of a control to apparatus for separatingsuccessive leading portions of fibrous material from a continuous fleece of such material in order to measure out predetermined quanti ties of the fleece by volume.

It is known to separate successive leading portions of cut tobacco from a fleece thereof by passing the fleece on a conveyor beneath a separator knife which is arranged to descend and cut through the fleece at intervals but it has been found that a deposit of sticky matter builds up on the knife causing interference with a guide member for the knife. This deposit must therefore be removedby frequent cleaning operations, or alternatively the knife must be frequently replaced by a clean knife. The present invention avoids the use of a knife with its attendant disadvantages.

' It has already been proposed to form cigar bunch charges from a layer of tobacco leaves on a horizontal chain belt by means of two series of prongs which extend across the'belt and are movable into the layer of leaves in close proximity to one another and then given a relative separating movement away from each other to tear a leading portion from the remainder of the layer. In that proposal a bottom series of prongs ascended vertically and a top series of prongs descended vertically, the open structure of the chain belt permitting both series of prongs to pass through it and overlap one another. When the top series of prongs had completed its vertical descent into the moving chain belt, it was propelled forwards to tear, or complete the tear of, the leading portion of the tobacco leaves.

The present invention is designed to treat fibrous material which by reason of its small particle size cannot be supported on an open-structure conveyor but requires an imperforate or chased-structure conveyor. A typical example of such material is cut tobacco for cigarettes known as rag" which, in addition to being finely cut, may also include small pieces of cut rolled stems. Theinvention may of course be used to treat other fibrous material such as wool.

According to the invention, there is provided apparatus for separating successive leading portions of fibrous material from a fleece thereof and comprising a conveyor for conveying the fleece substantially horizontally, a separator device located and operable above the conveyor and comprising two forks having sets of prongs which extend across the conveyor,'the forks being retractable together to inter-digitate their sets of prongs first means for moving the forks into and out of a fleece on the conveyor, second means for driving one of the forks away from the other fork in the direction of travel of the fleece on the conveyor so as to separate a leading portion of the fibrous material from the remainder of the fleece, and means for retract the forks together before they enter the fleece, the first means being arranged to move the forks downwards through the fleece with a component of motion in the direction of travel of the fleece on the conveyor.

By way of example one form of the invention will now be described with reference to the accompanying drawings of which,

system for the device,

FIG. 3 is a diagram relating to the cycle of operations of the separator device,

FIG. 4 shows the separator device in an extended condition, and

FIG. 5 is a horizontal section through a portion of the separator device taken in the plane VV of FIG. 2.

Referring to FIGS. 1 and 2 a continuous fleece or bed of fibrous material 110, e.g., tobacco"rag, is supplied by an upper'conveyor in the form of an endless belt 1 1 to the top inlet of a vertical transfer pipe 12 in which it falls down under gravity to reach a lower conveyor in the form of an endless belt 113 which is provided with a pair of fixed side walls 14 and is substantially horizontal. To assist a steady delivery of tobacco on to the conveyor 13, the pipe 12 has an increasing cross-sectional area and is provided at its lower end with a driven horizontal roller 15 whose working surface is arranged to form the inner wall of a bend section connecting the vertical pipe to the conveyor 13. The pipe 12 has sufficient head of tobacco to ensure a tobacco delivery of substantially uniform density. The belt 113 is imperforate in order to retain the short tobacco fibres on it.

In order to separate successive leading portions 17, l8, 19, etc., from the remainder of the fleece 10 for subsequent loading into individual containers, a rotary separator device together with a control system for its operation is provided above the fleece on the conveyor 13. This device comprises a pair of

forks

20, 21 having parallel dependent sets of prongs which extend across the conveyor 13 and face one another. The forks are shownin a retracted relationship wherein their respective sets of prongs are interdigitated as indicated in FIG. 5 so as to lie in a common vertical plane which extends at right angles across the conveyor 13. The prongs which have flat faces are tapered at their lower ends to facilitate their entry into the fleece.

Referring also to FIG. 4, the

forks

20, 21 are secured by brackets 22 to the undersides of

carriers

23, 24 respectively. Carrier 23 for the fork 20 is pivotally mounted on a pair of pivot pins 25 pivotably supported by a lower pair of vertical rotatable discs 26 adjacent to their rims. The discs 26 are fixed on co-axial

rotatable shafts

27, 28 supported in a frame 29, the shaft 28 carrying a driving sprocket 3i) and a cam 31.

The carrier 23 supports a pair of parallel guide rods 32 for the carrier 24 which extend overhead along the conveyor 13 and are fitted at their downstream ends with a stop plate 33. The carrier 24 for the fork 21 is secured to the base of a movable cylinder 34 of a pneumatic ram unit whilst the ram itself is rigidly secured by a rod 35 to a bracket on the top of the carrier 23. Operation of the ram unit controls the slidable movement of the carrier 24 along the guide rods 32 and thus the retraction and extension of the fork 21 to and from the fixed fork 20. It will be appreciated that the two forks, their carriers, and the ram unit comprise a fork assembly which is mounted on the arm 25 and follows a circular orbital path about the horizontal axis of the

shafts

27, 28 whenever the latter are driven.

The following mechanism is provided to maintain the prongs of the two forks pointing downwards throughout the orbital path of the fork assembly. The frame 29 also supports an upper pair of vertical rotatable discs 38 mounted on co-axial shafts 39 which are arranged to be driven from the

lower shafts

27, 28 by means of sprocket wheel and chain drives 40. The discs 38 are connected to the carrier 23 by means of a U-form connector 41 whose upper ends are mounted on eccentric pivot pins 42 carried by the discs 38 and whose lower portion is bolted or otherwise secured to the top of the carrier 23. By this arrangement the orientation of the carrier 23 and the remainder of the fork assembly is maintained as shown and thus the downward orientation of the fork prongs is also maintained.

Referring to the pneumatic ram unit, the opposing ends of the ram cylinder 34 are connected by

flexible air pipes

44, 45 respectively via a flow control valve 46 to a main valve housing 47 which in turn is connected to a source of compressed air through an air supply pipe 48. The main valve in the housing 47 is operated through a spring-returnable plunger 49 controlled by a pivotable cam follower 50 which rides the cam 31 on the drive shaft 28. The arrangement is such that for every revolution of the cam each

pipe

44, 45 in turn is arranged to supply compressed air to the ram cylinder 34. The drive for the cam 31 and also for the two pairs of

discs

26, 38 comes via the sprocket 30 which is connected to a motor (not shown). The latter is arranged to drive the sprocket 30 alternately slowly and quickly during each revolution of the sprocket.

Referring to FIG. 3, the circular orbital path for the fork assembly above the conveyor 13 is indicated by the reference numeral 52, the top of the fleece being indicated by the line 53. The orbital path has two sectors, viz., a slow lower sector and a fast upper sector. The slow or lower sector extends from point 54 which represents the position of the

descending forks

20, 21 just before entry into the fleece 10 *as seen in chain dot lines in FIG. 4) to point 55 which represents the position of the rising forks just after leaving the fleece. The fast or upper sector extends from point 55 to point 54, passing through the uppermost point, and represents the return movement of the forks. In the slow sector, point 56 represents the commencement of the extension stroke of the fork 21 whilst point 57 which is the lowermost point represents the completion of the stroke, i.e., when the fork 21 is fully extended. It is necessary to ensure that the fork 21 is retracted before the two forks re-enter the fleece and this retraction can be carried out at any suitable time after the forks have passed point 57. Conveniently the retraction takes place or finishes just before point 54.

In this example the conveyor 13 is moving continuously at a steady speed and the ram unit must be operated to extend or drive the fork 21 in a downstream direction at a speed of separation which is faster than the linear speed of the conveyed fleece, preferably five or six times faster. For cut tobacco, a stroke length of 6 inches for the fork 21 has been found satisfactory.

The apparatus may be operated as follows to provide a rapid succession of portions of tobacco of substantially equal volume for subsequent loading into individual tins or other containers. Before commencing operation, the linear speeds of the conveyors 11, 13 and the rotational speed of the drive to the sprocket 30 are selected to determine the required volume of the portions. which are to be obtained from the fleece and also their rate of production. Then the two conveyors and the roller 15 are brought into operation to prime the pipe and when the fleece 10 has reached the zone beneath the fork assembly the sprocket motor is started up.

Referring for convenience to FIGS. 2 and 4, the rotation of the discs 26 causes the retracted

forks

20, 21 with their interdigitated prongs to descend relatively slowly along an arcuate path into the fleece 10 with a component of motion in the direction of travel of the fleece which avoids or minimizes obstruction to the movement of the fleece on the travelling conveyor 13. As the forks reach the position corresponding to point 56in FIG. 3, the combined operation of the cam 31, its follower 50 and the plunger 49 operates the main air valve to disconnect the air supply pipe from pipe 45 and connect to its pipe 44; whereupon the ram cylinder 34 is driven away from the carrier 23 taking the fork 21 with it, this extension stroke being completed as the fixed or rear fork 20 reaches the lowermost position corresponding to point 57 in FIG. 3. The effect of the separation of the forks is to tear free and separate the fibrous leading portion 19 from the tobacco fleece, as shown in FIG. 4. The forks do not cut the fibres and they doe not attract any sticky deposit. Their descent is so arranged that they do not reach and rub against the conveyor belt 13.

During the extension or separating stroke the discs 26 are still rotating and so the separated forks now rise clear of the tobacco. As they reach the position corresponding to point 55 in FIG. 3, the sprocket motor changes its drive from slow to fast and the still separated forks enter the fast sector of their return movement. As the forks approach the position corresponding to point 54, the continued rotation of the cam 31 frees the plunger 49 to rise under the action of its return spring and operate the main valve to disconnect the air supply pipe from pipe 44 and re-connect it to pipe 45; whereupon the ram cylinder 34 is driven back to the carrier 23, retracting the fork 21, and causing the forks to resume their interdigitated relationship. The timing is such that retraction is complete just before the forks re-enter the fleece. Meanwhile the sprocket motor changes its drive from fast to slow as the forks reach the position corresponding to point 54 and enter the slow sector of the orbital path for the fork assembly. The cycle is then repeated with each revolution of the

shafts

27, 28. The apparatus described provides fast automatic measuring out by volume.

In a modification to the appartus, mechanism may be provided for imparting an impulse or a short stroke to the fork 20 which takes place in the opposite direction to the stroke of the fork 21 but commences at the same time as that stroke. The modification may be used whether the conveyor 13 is moving during the separating stroke or is temporarily stopped during the stroke. This modification may be used for fibrous material which is difficult to separate but it may result in bunching of the fleece.

Any other continuously operable means may be used for lowering and raising both forks together and for extending and retracting the downstream fork.

In a further modification, the conveyor 13 is provided with a pressure member, e.g., an upper endless belt, which extends between the roller 15 and the rotary separator device and is arranged to compress the tobacco fleece below it to a predetermined density.

What we claim is:

1. Apparatus for separating successive leading portions of fibrous material from a fleece thereof and comprising a conveyor for conveying the fleece substantially horizontally, a separator device located and operable above the conveyor and comprising two forks having sets of prongs which extend across the conveyor, the forks being retractable together to interdigitate their sets of prongs, first means for moving the forks into and out of a fleece on the conveyor, second means for driving one of the forks away from the other fork in the .direction of travel of the fleece on the conveyor so as to separate a leading portion of the fibrous material from the remainder of the fleece, and means for retracting the forks together before they enter the fleece, said first means being arranged to move the forks downwards through the fleece with a component of motion in the direction of travel of the fleece on the conveyor.

2. Apparatus according to claim 1, wherein the sets of fork prongs do not reach the floor of the conveyor.

3. Apparatus according to claim 1, wherein the first means are arranged to move the forks in an orbital path in a vertical plane.

4. Apparatus according to claim 3, wherein the orbital path is circular.

5. Apparatus according to claim 1, wherein the first means are arranged to move the forks through alternate slow and fast sectors, the downward movement of the forks through the fleece taking place in a slow sector.

6. Apparatus according to claim 3, wherein the second means are arranged to commence driving the one fork away from the other fork just before the forks reach their lowermost position.

7. Apparatus according to claim 1, wherein the second means are also arranged to drive the other fork a short distance in the opposite direction to the travel of the fleece on the conveyor simultaneously with the commencement of the drive of said one fork away from said other fork.

Claims

1. Apparatus for separating successive leading portions of fibrous material from a fleece thereof and comprising a conveyor for conveying the fleece substantially horizontally, a separator device located and operable above the conveyor and comprising two forks having sets of prongs which extend across the conveyor, the forks being retractable together to interdigitate their sets of prongs, first means for moving the forks into and out of a fleece on the conveyor, second means for driving one of the forks away from the other fork in the direction of travel of the fleece on the conveyor so as to separate a leading portion of the fibrous material from the remainder of the fleece, and means for retracting the forks together before they enter the fleece, said first means being arranged to move the forks downwards through the fleece with a component of motion in the direction of travel of the fleece on the conveyoR.

4. Apparatus according to claim 3, wherein the orbital path is circular.