DEVICE FOR FEEDING CIGARETTES TO THE WRAPPING LINE OF A PACKETING MACHINE

Abstract: A device for feeding cigarettes (2) to a packeting machine, comprising a hopper (1), the lower part of which contains the cigarettes (2) placed in stacks mobile stepwise along respective outgoing channels (6) from the hopper, a device (14) for checking the cigarettes (2) descending stepwise along the channels (6), and a device (19) for ejecting faulty cigarettes (2) which is controlled by the checking device (14) and comprises, for each channel, a pneumatic extractor (20) connectable to a suction source and comprising a withdrawal element (21) able to gain access to the respective channel (6) to extract the faulty cigarettes (2) from the interior of the hopper (1).

Description: This invention relates to a device for feeding cigarettes to the wrapping line of a packeting machine. The known practice is for the cigarettes to enter a packeting machine usually via a hopper which is supplied with the cigarettes in appropriate containers or from a belt conveyor, which conveys them in the form of a continuous layer. When leaving the hopper the cigarettes are grouped into batches, each of which is made up of a number of cigarettes equal to the number in one finished packet. A check is then made on the characteristics of the cigarettes of each batch, and those batches which contain even a single faulty cigarette are rejected. In order to reduce the number of batches of cigarettes ejected and thereby obtain a considerable financial saving, a device has been proposed by the present applicant, Messrs. G. D. S.p.A., in GB-A-2 150 807 which is able to verify the soundness of the cigarettes while these are still in the hopper, and to reject them before they reach the batching station. In this device the cigarettes are ejected from the hopper by a combination of pneumatic means and mechanical means. More specifically, when commanded by the means which check the cigarette soundness, a nozzle directs an air blast against the end of each faulty cigarette. Under the force of this blast the cigarette begins to emerge from the hopper through an appropriate aperture, so that its opposite end is pierced by a sharp element or needle. This latter, driven with reciprocating movement, withdraws from the hopper to thus complete the removal of the faulty cigarettes. A device of this type is not however free of problems, which derive both from the pneumatic means and from the mechanical means. The air blast directed against the end of the cigarettes tends to expel tobacco particles, which can fall onto the underlying members and hinder correct operation of the machine. A more serious problem arising in such a device derives from the use of said needles, or sharp element in general, which can constitute a danger to the operator if they break. In fig. 3 of GB-A-2150807 (=US-A-4592470), the faulty cigarette is expelled by suction action on the front face of said faulty cigarette, while in the present application a suction acts on the side of the filter, i.e. on that portion of the faulty cigarette offering greater impermeability. This important function is permitted due to the fact that the withdrawal element is in the form of a "curved plate" and enters into a seat or recess sideways of the filter. The object of the present invention is to provide a device of the above forementioned type in which the described problems of the know art do not arise. According to the invention, a device for feeding cigarettes to the wrapping line of a packeting machine is provided which devices is of the type comprising: a hopper for supplying cigarettes to said machine, the lower part of the hopper being divided by dividing walls into outgoing channels each having a width substantially equal to the diameter of a cigarette and through which the cigarettes, placed in stack, descend stepwise; sensor means associated with said channel for checking cigarettes in succession; a faulty cigarette pneumatic ejecting device, controlled by said sensor means for removing the faulty cigarettes from said hopper, comprising a withdrawal element for each said channel such and a suction source connected with said withdrawal element, said withdrawal element being arranged to engage and retain one cigarette and being mobile, parallel to the cigarette axes, between a withdrawal position, defined by an access communicating with the interior of the respective channel, and a disengagement position, in which said withdrawal element is spaced from said hopper by a distance at least equal to one lenght of one cigarette, and is characterized in that said withdrawal element has an end in the form of an elongated curved plate with its longitudinal axis parallel to the axes of the cigarettes, the concave surface of said curved plate being arranged to cooperate with the lateral surface of a cigarette and being provided with apertures communicating with said suction source. The present invention is described hereinafter with reference to the accompanying drawings, which illustrate a non-limiting embodiment thereof and in which: Figures 1 and 2 are sectional side views of the device according to the present invention in two different operating positions; Figure 3 is a front view of a detail of Figures 1 and 2; Figure 4 is a section through a detail of the device according to the invention; Figure 5 represents a control circuit, in the form of a block diagram, for the device according to the invention; and Figures 1 and 2 show an intake hopper 1, of known type, for feeding cigarettes 2, comprising a filter 3, to a cigarette packeting machine (not shown). The hopper is defined by a left-hand wall 4, facing the filters 3, and a right-hand wall 5, which are vertical and parallel to each other and define a compartment having a width approximate to but slightly greater than the length of one cigarette 2. This compartment is divided into a plurality of elementary channels 6 (of which only one is shown) by baffles or dividing walls 7 positioned at a distance apart approximate to but slightly greater than the diameter of the cigarettes 2 (see Figure 3). The elementary channels 6 are bounded at their bottom by a horizontal wall which supports the columns of cigarettes 2 contained in the channels 6. Said cigarettes 2 are engaged in batches at the end comprising the filter 3 by a pusher element 9 mobile with reciprocating motion perpendicular to the walls 4 and 5 through horizontal slits 10 and 11 provided in the walls 4 and 5 in a position adjacent to the wall 8 and of a height at least equal to the diameter of the cigarettes 2. The pusher element is movable from a non-active position outside the hopper 1 to an operative position inside the hopper 1 for pushing the cigarettes 2 from the channels 6 into containers 12 (of which only one is shown) carried by a conveyor belt 13 provided with intermittent motion, for transferring the batches of cigarettes 2 to a packeting unit, not shown. To understand better the structure of the hopper 1, the channels 6, the pusher element 9 and the conveyor belt 13, reference should be made to the description and drawings of U.K. Patent Nos. 1,298,785 and 2,023,994 in the name of the present applicant, Messrs. G.D. S.p.A. Along each channel 6, externally to the wall 5, there is provided a sensor means or device for checking the soundness of the individual cigarettes 2, and indicated overall by 14. Said checking device 14 is shown schematically in the figures as a sensor (of optical, or mechanical, or pneumatic type) able to detect defects in the extremity of each individual cigarette 2 via a horizontal hole 15 provided through the wall 5. Externally to the hopper 1 in proximity to the wall 4 facing the filters 3, there is provided a device 16 for axially adjusting the cigarettes 2. Said adjustment device 16 consists, for each channel 6, of an arm 17 pivoted on a horizontal pin 18 perpendicular to the axes of the cigarettes 2. Actuator means, not shown, impress on the device 16 a rocking movement of a frequency such as to cause the free end of the arm 17 to make contact, during each halt period of the stack, with the filter 3 of each cigarette 2 and exert a sufficient pressure to move those extremities to be checked into line with the wall 5. At a lower level than the checking device 14 there is provided a device for ejecting the faulty cigarettes 2, which is indicated overall by 19. Said device comprises, for each channel 6, a pneumatic extractor 20 provided with a withdrawal element 21 mounted on a block 22 supported by the pusher 9 via a bracket 23. Said withdrawal element 21, the level of which is lower than that of the respective sensor 14 by a distance equal to or a multiple of the diameter of one cigarette 2, has one end in the form of a curved plate with its axis parallel to the axes of the cigarettes 2 and its concave surface, indicated by 24, facing the interior of the respective channel 6. By means of the described connection, each extractor 20 is mobile together with the pusher 9 with axial reciprocating motion relative to the wall 4 of the hopper 1. More specifically, when the pusher 9 is located in its end-of-travel position below the hopper 1, each pneumatic extractor 20 occupies a position, indicated by 25 and defined as the withdrawal position, in which an access into the respective channel 6 is provided for the withdrawal element 21. This access consists of an aperture or hole 26′ formed in the wall 4 and, aligned with it, a seat or recess 26 formed in one of the two baffles 7 defining said channel 6 (see also Figure 3). In contrast, when the pusher 9 is in its non-active position outside the hopper 1, the withdrawal element 21 occupies a position of disengagement from the channel 6 outside the hopper 1 at a distance from this latter which is at least equal to the length of one cigarette 2. Above the device 19 there is provided a fixed horizontal plate 27, in contact with which the blocks 22 of each extractor 20 slide in an air-tight manner along their entire path. In the inward and outward end-of-travel positions occupied by each block 22, said plate 27 is provided with vertical holes indicated respectively by 28 and 29, the former being connected by a pipe 30 to a suction source and the latter being connected by a pipe 31 to a compressed air source, which are indicated schematically by the blocks 32 and 33 respectively. When each extractor 20 is in one of its end-of-travel positions the holes 28 and 29 in the plate 27 are aligned with a hole 34 communicating with a duct 35 extending inside the block 22 and withdrawal element 21 and connected to the outside via apertures in the form of holes 36 provided in the concave surface 24 of the withdrawal element 21. With reference to the block diagram of Figure 5, which represents a control circuit relative to each channel 6, the checking device is shown schematically as a normally open contact which closes when a cigarette 2 which is too short or not sufficiently full of tobacco at its extremity is detected. Connected to the output of the checking device 14 there is provided a memory device 37, which controls valve means comprising a first valve 39 connected into the pipe 30 and a second valve 40 connected into the pipe 31. When in use, during the halt stage of each machine cycle and therefore when the stacks of cigarettes 2 are at rest within the channels 6, each sensor 14 via its individual hole 15 checks a respective cigarette 2, which has previously been brought into contact with the wall 5 by the axial adjustment device 16. When a cigarette 2 is found to be faulty, the checking device 14 provides for its rejection by way of said memory device 37 and the valve means 38. More specifically, after a determined delay which depends on the level difference, evaluated in terms of machine cycles, between the checking device 14 and the extractor device 20, the normally closed valves 39 and 40 receive an opening command with the result that the two holes 28 and 29 become connected to the suction source 32 and to the compressed air source 33 by the respective pipes 30 and 31. As a result of this, when the faulty cigarette 2 travelling down the channel 6 reaches that halt position in which the extractor 20 operates, the withdrawal element 21, which is in its end-of-travel position within the seat 26 provided in the respective baffle 7, communicates with the suction source 32 via the connection means consisting of the hole 34 and the duct 35. The filter 3 of said cigarette 2 therefore adheres tightly to the concave surface 24 provided with the holes 36 deriving from the block 22, which on moving away from the wall 4 withdraws the faulty cigarette 2 from the stack. By virtue of the air-tight contact between the block 22 and plate 27, the suction force of the withdrawal element acting on the cigarette 2 does not cease after interruption of communication between the duct 35 and hole 28 as the block 22 slides towards its outer end-of-travel position. When the block 22 reaches its outer end-of-travel position on retraction of the pusher 9, means, of which the compressed air source 33 forms part, for separating the cigarettes 2 from the extractor 20 come into operation. In this respect, as the hole 29 in the plate 27 coincides with the hole 34, the compressed air source 33 is directly connected to the withdrawal element 21 so that air jets flowing through the holes 36 cause the faulty cigarette 2 to separate and fall into a collection vessel, not shown. It can be seen that the device according to the present invention is able to obviate all the described drawbacks of the known art. In this respect, those air blasts directed axially against the extremities of the cigarettes 2 are no longer present, such air blasts as stated resulting in dust and the escape of tobacco particles, nor are the needles which can constitute a danger to the machine operators, particularly on breakage. Within the principles of the inventive idea numerous modifications can be made to the said device without leaving the scope of the present invention. The sensor means could be located on both the walls 4 and 5 of the hopper 1 to check both extremities of the cigarettes 2. It should be noted that in the case heretofore described, in which only one extremity of the cigarettes 2 is checked, the withdrawal element 21 and the checking device 14 could be positioned mutually aligned, so as to effect the checking operation and the ejection of the possibly faulty cigarette 2 during the same machine cycle. With regard to the axial adjustment device 16, this instead of being mechanical could be of pneumatic type, for example consist of a nozzle connected to a compressed air source, not shown. In contrast, the means for separating the faulty cigarettes 2 from the extractor 20 could be of mechanical instead of pneumatic type, and consist for example of a bar 42 which when the extractor 20 is in its outer end-of-travel position strike the cigarette 2 transversely to its axis.

Claims: 1. A device for feeding cigarettes to the wrapping line of a packeting machine comprising: a hopper (1) for supplying cigarettes (2) to said machine, the lower part of said hopper being divided by dividing walls (7) into outgoing channels (6) each having a width substantially equal to the diameter of one cigarette and through which the cigarettes, placed in stack, descend stepwise; sensor means (14) associated with said channels for checking cigarettes in succession; a faulty cigarette pneumatic ejecting device (19), controlled by said sensor means for removing the faulty cigarettes from said hooper, comprising a withdrawal element (21) for each said channel and a suction source (32) connected with said withdrawal element, said withdrawal element being arranged to engage and retain one cigarette and being mobile, parallel to the cigarette axes, between a withdrawal position, defined by an access (26) communicating with the interior of the respective channel, and a disengagement position, in which said withdrawal element is spaced from said hopper by a distance at least equal to one length of one cigarette, characterized in that said withdrawal element (21) has an end in the form of an elongated curved plate with its longitudinal axis parallel to the axes of the cigarettes, the concave surface (24) of said curved plate being arranged to cooperate with the lateral surface of a cigarette (2) and being provided with apertures (36) communicating with said suction source (32). 2. A device according to claim 1, characterized in that at least in correspondence with said withdrawal position, valve means are provided for connecting said withdrawal element (21) to said suction source (32).

Inventors: GAMBERINI, ANTONIO, GHINI, MARCO
Applicants: G.D. SOCIETA PER AZIONI
Application year: 1989
Main classification: B65B19
IPC codes: B65B19, B65B57, A24C5