Machine for wrapping cigarette packs, or the like, into sheets of a wrapping material

Abstract: A machine for wrapping cigarette packs (P) or the like into a wrapping material sheet (F) comprises a stepwise-operatable spoke wheel (1) formed with a plurality of outwardly open radial pockets (4) for receiving packs (P) with the relative wrapping material sheet (F) from a feeding station (A), each pocket (4) being provided at the trailing end of its mouth - relative to the direction of rotation of the spoke wheel (1), with radial teeth (214) for retaining in position the trailing flap (L1) of the wrapping material sheet flaps (L1, L2) which are folded on the respective pack by folder means (5, 6). The said folded flaps (L1, L2) are welded together by welding means (7, 8) which are imparted a radially directed reciprocating motion between the one and the successive step of the spoke wheel (1), so that any interference is avoided with the said retaining teeth (214). The said welding means (7, 8) are operated by driving means which consist of main driving means (10, 11) and an auxiliary driving means (18) that is timely set in action only when the operation of the main driving means is discontinued, whereby the function and the integrity of the machine is guaranteed.

Description: The invention relates to a machine for wrapping packs substantially having the shape of a rectangular parallelepiped, particularly for wrapping cigarette packs, individually into a generally transparent wrapping material sheet which is rather flexible and/or is liable to be affected by static electricity and which may be, for example, of polyethylene, or the like, according to the pre-characterizing part of Claim 1. A machine of this kind is known from the document EP-A-0374712. In order to prevent any interference between the teeth and the welding means, and since it is not possible to have suitable grooves provided for the welding means, which grooves would hinder the continuity of the welding lines, and so the tightness of the pack wrappers, in the said known machine there is proposed that each pack be shifted at the welding stations, radially within the pocket in which it is housed, with the respective welding means, which can be then left in a substantially stationary condition. However, the practical experience demonstrate that such a radial shifting of each pack within its respective pocket housing the same, may cause the wrapper thereof to become badly formed. In fact, owing to any frictional resistance between the contacting pack-and-wrapper surfaces, the wrapping material sheet may be caused to take, relative to its pack, a position other than its original position. In a machine for wrapping cigarette packs, known from the document FR-A-2277732, but different from the machine according to the pre-characterizing part of Claim 1, are disclosed auxiliary driving means being operatively associated with the main driving means which will be set in action for promoting, whenever the operation of the main driving means should be discontinued for any reason, at least the radial withdrawing from the relative pack of a welding means or of each of the welding means, so as to move the welding means into inactive position, before the spoke wheel having been nextly indexed by one step. The present invention aims to overcome the aforesaid drawback of the machine known from the document EP-A-0374712 and, to this end, its object is a machine according to the pre-characterizing part of Claim 1, wherein - while the retaining teeth are still used - the aforementioned radial movement of the packs can be given up, by providing for a welding means or for welding means to be imparted a reciprocating motion by means of a driving device which garantees that the welding means and the said teeth will not interfere with each other, and which is of a very simple construction and affords an automatic, extremely reliable operation. This problem is solved by the invention by the combination of features according to the characterizing part of Claim 1. The features of a preferred embodiment of a machine according to the invention and the advantages resulting therefrom will appear from the following description and the attached drawings, in which: Figure 1 is a front view, with parts broken away, of a cellophaning machine according to the invention, and Figure 2 is a corresponding top plan view of the said machine. Referring to Figure 1, a cellophaning machine, according to the invention, comprises a spoke wheel 1 consisting of a rotary drum 2 mounted on to a shaft 3. The drum 2 is provided with a plurality of angularly equispaced radial pockets 4 which are each formed by at least one pair of spaced apart radial arms 104, 204, respectively providing the leading and the trailing side of a pocket - relative to the direction of rotation of the spoke wheel 1, as shown by arrow F1. The spoke wheel 1 is stepwise rotated so as to have each pocket 4 moved into a feeding station A, where it will receive a cigarette pack P which is arranged therein with its major axis lying parallel to shaft 3, and with its radially outward side slightly projecting from the respective end edge of arms 104, 204. Before a pack being inserted into its pocket, a wrapping material sheet F is interposed between the pack and the pocket, and while this sheet is being inserted into its pocket, it is "U"-wrapped around the pack, with both of its flaps L1, L2 being left beyond the pocket mouth. At the feeding station A a reciprocating folder 5 is provided, and has the task of folding the trailing flap L1 of a wrapping material sheet F on a pack P, once the pack has been accomodated into its respective pocket 4. Downstream of the station A - relative to the direction of rotation F1 of wheel 1, an arcuate stationary folder 6 is arranged, and as the wheel is being nextly rotated by one step, this folder will fold the leading flap L2 of said wrapper over the previously folded flap L1. The trailing arm 204 of each pocket 4 is provided at the radially outward edge of its free end with a retaining tooth 214 which by preventing any backward movement of the already folded flap L1, helps to keep the sheet F tightly wrapped around a pack P. In order to avoid that the folders 5 and 6 may interfere with the teeth 214, these folders are provided respectively with an open slot 105 and a radial groove 106, which are formed in a matching relation with the said teeth. The overlapped flaps L1 and L2 of a wrapping material sheet F for each pack P, are welded together at two successive steps of the spoke wheel 1, by a pair of welding means 7 and 8 arranged downstream of station A. These welding means which are allowed to contact the relative pack through a respective opening 9 formed in the stationary folder 6, are imparted an alternate oscillatory motion, such that the welding means will be moved from an active flap-welding position against the pack wrappers, into an inactive position away from the packs, in which any interference between the welding means and the aforementioned retaining teeth 214 is prevented. The actuation of the welding means 7 and 8 synchronously with the indexed rotation of the spoke wheel 1, is normally derived from a stepwise-operated motor 10, through a pair of linkages 11 which connect the said welding means to the shaft 110 of the said motor (see also Figure 2). Preferably, each linkage 11 comprises a rod 12 which is adjustable in length, and one end of this rod is pivotally connected to the respective one of two diametrically opposite ears 113 formed in a head 13 keyed onto the shaft 110 of motor 10, while the opposite end of said rod is pivotally connected to a lever 14 which in turn carries a pivot pin 15 pivotably engaged in a supporting member 16. Secured to this pivot pin 15 is a small plate 17, and the body of the respective one of the welding means 7, 8, is mounted on to this plate. When the shaft 110 of motor 10 is rotated over a fraction of a turn, alternately in the one and the contrary direction, possibly with the aid of return spring means (not shown), the two welding means 7 and 8 will be moved, through the said drive transmission linkages 11, in the manner as described above. Typically, the invention provides for an auxiliary device 18 to be operatively associated with the stepwise-operated motor 10, having the task of actuating the welding means 7 and 8 whenever the motor 10 cannot, for any reason, perform its function. Thanks to the provision of such an auxiliary device, a continuous operation of the cellophaning machine is thus ensured, and particularly any interference between the welding means 7 and 8 and the retaining teeth 214 is in any case avoided, whereby the integrity of this machine is safeguarded. According to one preferred embodiment of the auxiliary driving device, for which reference should be made to both Figures, the said auxiliary driving device 18 comprises a rotary cam 19, with a roller 20 being engageable therewith and being mounted on a lever 21 in turn keyed onto the rear end of shaft 110 of motor 10, which is the shaft end lying opposite to the shaft end carrying the head 13. The rotary cam 19 is provided with such a profile that a reciprocating oscillatory motion, which is just like the reciprocating oscillatory motion as promoted by the stepwise-operated motor 10, will be imparted to the shaft 110 through the roller 20 and the lever 21, and so to the welding means 7, 8 through the linkages 11. However, the cam 19 is operated with a little delayed phase difference relative to the motor 10, so that in normal conditions, it is this motor that actually drives the welding means, while the cam is only allowed to ligthly touch the cooperating roller 20, with no force being transmitted from the cam to the roller, the said cam being however ready for engaging the said roller, in case the operation of the main motor 10 should fail. Of course, the delayed operation of the cam 19 must be so calculated that, whenever needed, this cam will be allowed to actuate the welding means, and particularly withdraw the welding means from the respective packs, before the spoke wheel 1 having been nextly indexed by one step. The cam 19 is imparted a continous rotary motion, and since it is provided with only one peripheral projection 119, the same must be caused to make one turn for every step of the spoke wheel 1. In the shown embodiment, the auxiliary driving device is of a very simple construction, and affords an automatic, extremely reliable operation, and such positive features mainly result from a continuously rotated cam being used as a control means, which is set in action only in those generally rare occasions in which the normal operation of the main driving device is discontinued.

Claims: A machine for wrapping packs (P)- substantially having the shape of a rectangular parallelepiped, particularly for wrapping cigarette packs, individually into a generally transparent wrapping material sheet (F) which is rather flexible, and/or is liable to be affected by static electricity, and which may be, for example, of polyethylene, or the like, the said machine comprising a spoke wheel (1) with a plurality of angularly equispaced radial pockets (4), which are radially outwardly open, and which by the indexed rotation of the spoke wheel (1), are successively moved into a feeding station (A) wherein each pocket (4) will receive a pack (P) and the relative wrapping material sheet (F) which on being inserted into the respective pocket (4), is "U"-bent around its pack (P), with its radially directed flaps (L1,L2) protruding from the mouth of its pocket (4), and of these flaps, the flap (L1) which is the trailing flap relative to the direction of rotation of the spoke wheel (1), is first folded on the respective, radially outward end side of a pack (P) by a reciprocating folder (5) arranged in the feeding station (A), and the leading flap (L2) is then folded over the first folded trailing flap (L1), as the spoke wheel (1) is being nextly rotated by one step, by a stationary folder (6) mounted downstream of the feeding station (A), the said pockets (4) being each provided at the trailing end edge of their radially outward mouth - still relative to the direction of rotation of the said wheel (1), with one or more retaining teeth (214) which slightly protrude radially from the outward side of a pack (P), once this pack has been fully accomodated into its pocket (4), and open slots (105) in the reciprocating folder (5) and grooves (106) in the stationary folder (6) being provided in a matching relation with the said teeth, for allowing the teeth to pass therethrough, and one or more welding means (7,8) being provided and arranged around the spoke wheel (1) downstream of the feeding station (A), which are for welding together the said overlapped flaps (L1,L2) of the wrapping material sheet (F) for each single pack (P), the said machine being characterized in that it comprises a main driving means (10,11) which is for actuating a welding means or each of the welding means (7,8), so as to move the welding means in a substantially radial direction, between the one and the successive step of the spoke wheel (1), reciprocatingly from an active flap-welding position, in which the welding means are each moved into contact with the radially outward end side of a pack (P), into an inactive position in which the same are each withdrawn from the respective pack (P), to a sufficient degree for preventing any interference with the said teeth (214) in pockets (4), on the spoke wheel (1) being nextly indexed by one step, and an auxiliary driving means (18) being operatively associated with the said main driving means (10,11), which will be set in action for promoting, whenever the operation of the main driving means should be discontinued for any reason, at least the radial withdrawing from the relative pack (P) of a welding means or of each of the welding means (7,8), so as to move the welding means into inactive position, before the spoke wheel (1) having been nextly indexed by one step, the said auxiliary driving means (18) is so provided that the same is continuously kept in motion, and is automatically connected with a welding means or each of the welding means (7,8) only when the operation of the main driving means (10,11) should be discontinued. The wrapping machine according to Claim 1, in which a welding means or each of the welding means is imparted a reciprocating oscillatory motion in a substantially radial direction. The wrapping machine according to Claim 2, in which the said main driving means (10,11) comprises a step-wise-operated motor (10) and at least one linkage (11) which connects the shaft (110) of the said stepwise-operated motor (10) to a welding means or to each of the welding means (7,8). The wrapping machine according to Claim 3, in which each linkage (11) comprises a rod (12) which is adjustable in length, and one end of this rod is pivotally connected to the respective one of two diametrically opposite ears (113) formed in a head (13) keyed onto the shaft (110) of the stepwise-operated motor 10, while the opposite end of said rod (12) is pivotally connected to a lever (14) carrying in turn a pivot pin (15) which is pivotably engaged in a supporting member (16), a small plate (17) being secured to the said pivot pin (15), with the body of a welding means or of the respective welding means 7,8 being mounted on to the said plate. The wrapping machine according to Claim 4, in which the auxiliary driving means (18) comprises a rotary cam (19), with a roller (20) being engageable therewith and being mounted on a lever (21) which in turn is keyed onto the shaft (110) of the stepwise-operated motor (10), the said rotary cam (19) being provided with such a profile that a reciprocating oscillatory motion, which is just like the reciprocating oscillatory motion as promoted by the said stepwise-operated motor (10), will be imparted to the shaft (110) of the stepwise-operated motor (10), and so to a welding means or to each of the welding means (7,8), the said cam (19) being operated with a little delayed phase difference relative to the stepwise-operated motor (10), so that in normal conditions, it is this motor that actually drives a welding means or the welding means (7,8), while the cam (19) is only allowed to lightly touch the cooperating roller (20), with no force being transmitted from the cam to the roller, the said cam being however ready for engaging the said roller - in case the operation of the stepwise-operated motor (10) should fail, whereby a welding means or the welding means will be suitably actuated before the spoke wheel (1) being nextly indexed by one step.

Inventors: CAVAZZA ROBERT, CAVAZZA, ROBERT
Applicants: SASIB SPA, SASIB S.P.A.
Application year: 1991
Main classification: B65B11
IPC codes: B65B19, B65B51, B65B11, B65B65