GB2212706A - Distributor for feeding tobacco - Google Patents

Description

U 221270f 0 CIGARETTE MANUFACTURING MACHINE The present invention relates

to a cigarette manufacturing machine.

Cigarette manufacturing machines are known to feature a distributor designed to receive shredded tobacco from a supply device, and feed it through a carding unit and down-flow duct to a withdrawal unit by which the tobacco is withdrawn from and fed, in the form the bottom end of the down-flow duct of a relatively thin layer, on to a conveyor belt. Said tobacco layer is fed on the conveyor belt to the bottom end of an up-flow duct, up which the tobacco particles are sucked on to the underside of one or more suction type belts on a unit for forming a conti- nuous tobacco bead from which to form a continuous cigarette rod. The main requisite of a cigarette manufacturing machine is that the continuous cigarette rod so formed should be as homogeneous as possible. Generally speaking, this depends on the homogeneous nature of the tobacco layer form - 2 ed on the conveyor belt, which, in turn, depends on the consistency with which the tobacco is withdrawn by said withdrawal unit from the bottom end of the down-flow duct, and the manner in which the tobacco is fed along the same.

On known cigarette manufacturing machines, said down-flow duct usually presents a constant, substantially rectangular section, the longer side of which extends crosswise in relation to the travelling direction of the conveyor belt. Tests have shown that force of gravity alone is not enough for ensuring consistent flow along the down-flow duct, thus resulting in uneven distribution along the conveyor belt. One attempt to overcome this drawback consists in de fining the bottom portion of the duct by one or more walls moving horizontally and parallel with the longer sides of the duct, and providing said walls with a number of vertical ribs for separating the tobacco in the bottom portion of the duct. Such an arrangement, however, has failed to provide a satisfactory solution to the problem. The aim of the present invention is to provide a cigarette manufacturing machine featuring a distributor designed to form a more homogeneous tobacco layer on said conveyor belt than that achievable by known distributors. With this aim in view, according to the present invention, there is provided a cigarette manufacturing machine comprising a shredded tobacco distributor, in turn, comprising a tobacco down-flow duct, means for feeding said tobacco to the inlet of said duct, and means for withdrawing said tobacco from the outlet of said duct; characterised by the fact that said duct comprises at least one wall swinging substantially longitudinally in relation to the 1 1 1 1 travelling direction of the tobacco along said duct; said wall presenting, inside said duct, a number of ribs extending crosswise in relation to said duct. A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which Fig.1 shows a schematic vertical section of part of a cigarette manufacturing machine in accordance with the teach ings of the present invention; Fig.2 shows a larger-scale view of a detail on the Fig.1 machine. Number 1 in Fig.1 indicates a cigarette manufacturing ma-chine comprising a distributor 2 for forming a continuous, even stream of tobacco particles from a mass of shredded tobacco. The component parts of distributor 2 are housed in a vertical casing 3 defined at the top by a horizontal wall 4 and laterally by two vertical walls 5 and 6. On the two sides parallel with the Fig.1 plane, casing 3 is defined by a front wall 7 and a rear or end wall 8. Top wall 4 presents an opening for a rectangular-section input duct 9, beneath which are provided, inside casing 3, two powered rollers 10 and 11 having radial teeth 1.2. Rollers 10 and 11 are turned in opposite directions for pre- carding and feeding the tobacco into an underlying chamber 13. Duct 9 and rollers 10 and 11 combine to form a prefeed unit 14 over chamber 13, the bottom of which is defined by a conveyor belt 15 consisting of the top branch of a belt 16 looped about three direction rollers 17, 18, 19, at least 4 - one of which is powered, and a belt stretching roller 20. Two inclined, converging walls 21 and 22, both extending downwards from wall 4, feed the tobacco dropping down from prefeed unit 14 on to belt 15.

On the opposite side to wall 6, chamber 13 is defined by a toothed carding roller 23 forming part of a carding or main feed unit 24 at the downstream end of belt 15. Beneath roller 23, there is provided a cylindrical element 25 coaxial with roller 23 and one end of which is fitted 26 extending between roller 23 and belt 15. 23, unit 24 also comprises a so-call turning in the same direction as rol over and substantially tangent to the with a scraper elemeni the downstream end of In addition to roller ed metering roller 27 ler 23 and located same.

-By virtue of the above arrangement, the tobacco fed by pre feed unit 14 on to underlying belt 15 is fed by belt 15 through scraper element 26 on to carding roller 23. Carding roller 23 withdraws from chamber 13, and transfers downstream from the point of tangency with metering roller 27, a layer of tobacco substantially equal in thickness to the radial dimension of its teeth. Said tobacco layer is received off roller 23 by a toothed so-called hurling roller 28, and hurled, in the form of separate particles, into a feedbox 29 communicating with the inlet of a substantially vertical down-flow duct 30 defined by two walls 31 and 32. The bottom end of duct 30 presents an outlet facing a withdrawal unit 33 comprising a mobile conveying element facing said outlet and consist- ing of a toothed roller 34 designed to withdraw the tobac- co from duct 30 and turning about an axis parallel with that of carding roller 23. Unit 33 also comprises a toothed, so-called hurling roller 35 for receiving the tobacco off the teeth of roller 34 and hurling it, in the form of separate particles, into a chamber defined at the bottom by a so-called collecting belt 36 moving upwards and leftwards as shown in Fig.l. Belt 36 consists of the top branch of a belt 37 looped about three direction rollers 38, 39 and 40, at least one of which is powered, and held taut by a belt stretching roller 41. Roller 38 is located adjacent to the bottom end of an upflow duct 42, the top end of which (not shown) communicates with a continuous cigarette rod forming unit (not shown). On said rod forming unit, the tobacco particles cling to the underside of at least one suction type conveyor belt (not shown) so as to form, on the same, a continuous layer of tobacco (not shown).

As shown, particularly in Fig.2, duct 30 presents a substantially rectangular section, and comprises an upper inlet portion 43 connected to the outlet of feedbox 29, and a lower outlet portion 44 the bottom end of which communicates with a curved passage 45 extending about roller 34 and swept by the radial teeth on the same. Part of the surface of outlet portion 44 at the confluence of duct 30 and passage 45 is defined by a feed roller 46 mounted for rotation on a fixed support 47 located downstream from duct 30 in the travelling direction of the to- bacco along the same, and substantially tangent to roller 34. Roller 46 cooperates with roller 34 for withdrawing tobacco from the bottom end of duct 30, and presents a corrugated or knurled surface. Opposite roller 46, outlet portion 44 of duct 30 is defined by a movable wall 48 sloping in the direction of passage 45 and in relation to wall 32. Wall 48 substantially constitutes a lower continuation of wall 32, and presents, on the surface inside duct 30, a number of straight, parallel, horizontal ribs or projections 49 arranged one over the other, parallel with the axis of roller 46 and crosswise in relation to duct 30. Said ribs 49 are substantially serrated, with their tips facing roll er 34. Outside duct 30, wall 48 is supported on a perpendicular bracket 50 having a center portion pivoting via pin 51 on the end of arm 52 of a two-armed lever 53. Said two-armed lever 53 pivots on a bracket integral with wall 32 of duct 30, and has its free end connected via connecting rod 54 to an actuator 55 consisting, for example, of a cam (not shown) designed to swing wall 48 horizontally via connecting rod 54 and lever 53. The free end of bracket 50 is con nected via connecting rod 56 to an actuator 57 consisting, for example, of a cam (not shown) designed to swing bracket 50 about pin 51.

In actual use, combined operation of actuators 55 and 57 provides for swinging wall 48 substantially horizontally in relation to the travelling direction of the tobacco in duct 30. Wall 48 is preferably swung along a flat elliptical path, as shown by the dotted line in Fig.2, having its longer axis substantially parallel with the travelling di- 1 rection of the tobacco in duct 30, so as to provide, in conjunction with ribs 49 on wall 48, for improved downflow and compacting of the tobacco. Homogeneous filling of the spaces between adjacent teeth on roller 34, and the formation of a homogeneous tobacco layer on belt 36, are assisted by roller 46, which mainly provides for eliminating friction between the tobacco and the surface of outlet portion 44, and so preventing tobacco from accumulating at the confluence of duct 30 and passage 45. To those skilled in the art it will be clear that changes may be made to the cigarette manufacturing machine as described and illustrated herein without, however, departing from the scope of the present invention.

For example, wall 48 may be located higher up inside duct 30, or two walls 48 may be provided, one on either side of duct 30. Furthermore, wall 48 may be designed to swing back and forth in strictly reciprocating manner, substantially pa- rallel with the travelling direction of the tobacco inside duct 30.

Claims (2)

1. Clain A cigarette manufacturing machine comprising a shredded tobacco distributor. in turn, comprising a tobacco down-flow duct, means for feeding said tobacco to the inlet of said duct and means for withdrawing said tobacco from the outlet of said duct; characterised by the fact that said duct comprises at least one wall swinging substan- tially longitudinally in relation to the travelling di rection of the tobacco along said duct, said wall presenting, inside said duct a number of ribs extending crosswise in relation to said duct.
2. 2) A cigarette manufacturing machine as claimed in 1, characterised by the fact that said wall swings along a substantially elliptical path having its longer axis substantially parallel with the travelling direction of the tobacco in said duct 3) - A cigarette manufacturing machine as claimed in Claim 1, characterised by the fact that said wall swings along a straight path, substantially parallel with the travelling direction of the tobacco in said duct 4) - A cigarette manufacturing machine as claimed in any one of the foregoing Claims from 1 to 3, characterised by the fact that said ribs are substantially serrated.

   5) - A cigarette manufacturing machine as claimed in any one of the foregoing Claims, characterised by the fact that said wall moves back and forth at different speeds, the forward speed in the down-flow direction of the tobacco in said duct being greater than the re turn speed.

   I - 9 j, 6) - A cigarette manufacturing machine substantially as described and illustrated herein with reference to the accompanying drawings.

   Publi,shed 1989 at The Patent Office, State House, 6671 High Holborn, London WClR4TP.FuMher copies may be obtained from The Patent Offtce. Sales Branch, St Mary Cray, Orpington. Kent BR5 3RD- Printed by Multiplex techniques ltd. St Mary Cray. Kent, Con. 1187