Abstract:
Apparatus for transporting rod-shaped tobacco smoke filters which contain and/or carry particles of charcoal and/or other solid particulate tobacco smoke filtering and/or flavoring material. A sender directs a series of successive filters lengthwise into a pneumatic conduit wherein the filters advance toward a receiving station. A section of the conduit has an arcuate shape and advances successive filters from a lower level to a higher level. The underside of the section has an elongated arcuate opening which is overlapped by a cover in such a way that any solid particles which became separated from the filters can be expelled into a neighboring chamber due to fluid pressure in the section as well as under the action of gravity and/or centrifugal force. Such particles are evacuated by way of an outlet at the lower end of the chamber, either by manually operated valves which control the admission of particles from the chamber into a compartment and from the compartment, or by automatically operated valves which open at close at predetermined intervals.

Description:
CROSS-REFERENCE TO RELATED CASES 
     This application claims the priority of German patent application Serial No. 199 13 427.7 filed Mar. 25, 1999. The disclosure of the above-referenced German patent application, as well as that of each U.S. and foreign patent and patent application mentioned in the specification of the present application, is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to improvements in apparatus for manipulating sections of rod-like filters for tobacco smoke, and more particularly to improvements in apparatus for transferring sections of rod-like filters which contain pulverulent, granular and analogous solid ingredients, such as charcoal. 
     It is often necessary to transport rod-like filters for tobacco smoke (hereinafter called filters for short) between two spaced-apart locations, particularly between a sender (such as a filter rod maker) which is set up to deliver successive filters of a short or long series of filters lengthwise into a pneumatic conveyor for transport to a receiving station, e.g., to the magazine of a filter tipping machine. Such apparatus are often equipped with arrangements which are designed to intercept, collect and dispose of solid particles which become separated from the rod-like filler (such as a filler consisting of crepe or acetate fibers). In the absence of any undertakings to the contrary, stray particles of charcoal or the like which become separated from filters in the pneumatic conveyor are likely or bound to contaminate the conveyor and/or the receiving station to an extent which necessitates temporary stoppages of the apparatus in order to carry out a cleaning operation or to permit a restarting of the apparatus. 
     Moreover, loose particles of charcoal or the like tend to adhere to the external surfaces and to thus contaminate the tubular wrappers of the filters. 
     Attempts to gather stray particles of charcoal or the like in apparatus which are designed to transport rod-like filters for tobacco smoke are disclosed, for example, in commonly owned British patent specification No. 1 410 473 (published Oct. 15, 1975) and in the U.S. Pat. No. 5,556,236 granted Sep. 17, 1996. The aforementioned patents share the feature that an arcuate section of the pneumatic conveyor is provided with an opening for the evacuation of solid particles which escape from the rod-like fillers of the filters and/or become separated from the external surfaces of the tubular envelopes for the fillers. The solid particles can be selected to enhance the tobacco smoke filtering action and/or to enhance the flavor of tobacco smoke furnished by a lighted filter cigarette, cigar or cigarillo. 
     Certain presently known filter lines which are capable of introducing particles of charcoal or the like into the fillers of acetate fibers or the like are known as AC 2 and AC 3 (both distributed by the assignee of the present application). The operation of each of these AC machines is based on the principle that charcoal is fed into a collector where it stays until a demand signal from a reservoir initiates a feed operation. Each AC machine cooperates with a filter rod making machine (e.g., a machine known as KDF and distributed by the assignee of the present application), and each filter rod making machine can be equipped with means for aspirating stray granules off the so-called garniture of the filter rod making machine by resorting to a so-called extraction hood which returns the aspirated granules to the source by way of a pipeline or the like. 
     OBJECTS OF THE INVENTION 
     An object of the present invention is to provide an apparatus which can transport rod-like filters for tobacco smoke in such a way that all or nearly all loose solid particles (such as charcoal granules) advancing with the filters from a sender to a receiving station can be intercepted, collected and disposed of (e.g., reused) with a higher degree of reliability than in heretofore known apparatus. 
     Another object of the invention is to provide a novel and improved pneumatic conveyor for use in the above outlined apparatus. 
     A further object of the invention is to provide an apparatus which prevents pronounced and/or long-lasting frictional engagement between the external surfaces of tubular wrappers of rod-like filters for tobacco smoke and stray particles of charcoal and the like. 
     An additional object of the invention is to provide a novel and improved module which can be utilized to convert a conventional filter manipulating apparatus into a superior apparatus capable of intercepting and gathering much higher percentages of loose solid particles of charcoal and the like. 
     Still another object of the invention is to provide a novel and improved method of intercepting, gathering and evacuating loose particles of charcoal or the like from apparatus for transporting and/or otherwise manipulating rod-like filters for tobacco smoke. 
     A further object of the invention is to provide a rod-like filter for tobacco smoke which is produced in the above outlined novel apparatus and/or in accordance with the above-outlined method. 
     SUMMARY OF THE INVENTION 
     One feature of the present invention resides in the provision of an apparatus for transporting tobacco smoke filtering rods, which carry solid particles (such as charcoal granules), along an elongated path extending from a sender (such as a filter rod maker) to a receiving station (e.g., into the magazine of a filter tipping machine). 
     The improved apparatus comprises a pneumatic conveyor defining an elongated path for lengthwise advancement of successive filtering rods of a file of filtering rods by means of a pressurized pneumatic fluid (such as compressed air) in a direction from the sender to the receiving station. The conveyor comprises a section which is located downstream of the sender, which extends along an arc of less than 180° (for example, along an arc which equals or approximates 90°), and which is arranged to advance successive filtering rods from a lower level to a higher level. The conveyor section has an at least substantially sealed arcuate upper side and an at least partially open arcuate underside, and the improved apparatus further comprises a cover which overlies the underside of the conveyor section and is arranged to permit expulsion of loose solid particles from the elongated path into a chamber of a collecting device but to interfere with appreciable flow of pressurized gaseous fluid from the conveyor section into the chamber of the collecting device. 
     The conveyor section is or can be adjacent (e.g., closely or very closely adjacent) the sender. 
     The internal surface of the conveyor (such as an elongated conduit) has an internal surface which can include a convex portion at the upper side and a concave portion at the underside of the conveyor section. 
     The cover is or can be elongated and can include a first end portion and a second end portion at a level above the first end portion; one of these end portions (preferably the upper end portion) is or can be provided with a lug, flap or an analogous deflector for gaseous fluid. 
     The cover can have a concavo-convex shape, and its concave side can confront the underside of the conveyor section. For example, the cover can be made (at least in part) of metallic sheet material and can be precurved at the locus of manufacture. 
     An upper end portion of the aforementioned collecting device can be installed downstream of the lower end portion (as seen in the direction of advancement of filtering rods from the sender to the receiving station), and the lower end portion can be provided with at least one outlet for collected solid particles. 
     The at least one outlet can define at least one compartment having a particle receiving portion and a particle discharging portion. A first open-and-shut valve can be employed and actuated to connect the receiving portion of the compartment with the chamber of the collecting device, and a second open-and-shut valve can be provided and actuated to permit and interrupt evacuation of solid particles from the discharging portion of the compartment. Alternatively, the at least one outlet can include automatically operable valve means serving to establish and to interrupt communication between the chamber of the collecting device and the at least one compartment of the outlet. For example, the automatically operable valve means can include means for permitting and interrupting evacuation of solid particles from the at least one compartment. Such valve means can be arranged to regulate the admission of solid particles into and the evacuation of solid particles from the at least one compartment as a function of time. 
     The aforementioned conveyor section can form part of a prefabricated module, preferably a mobile module. The conveyor section which forms part of such mobile module can be detached from and separably connected to additional sections of the conveyor. 
     The receiving station can include a magazine or other suitable means for temporarily storing at least one supply of filtering rods. 
     The sender can include means for pneumatically propelling filtering rods into an inlet of the pneumatic conveyor upstream of the aforementioned conveyor section (as seen in the direction of advancement of filtering rods toward the receiving station). Furthermore, the sender can include means for advancing filtering rods in several directions, for example, first (e.g., downwardly) along an at least substantially vertical path and thereupon along a substantially horizontal path. 
     The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling and operating the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of numerous presently preferred specific embodiments with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partly schematic elevational view of an apparatus which embodies one form of the invention, portions of the sender being shown in a vertical sectional view; 
     FIG. 2 is an enlarged elevational view of a mobile module including a conveyor section constructed and configurated in accordance with one presently preferred embodiment of the invention; 
     FIG. 3 is an enlarged view of a detail of the structure shown in FIG. 2; 
     FIG. 4 is an enlarged schematic transverse sectional view substantially as seen in the direction of arrows from the line A—A in FIG. 3; and 
     FIG. 5 is a similar sectional view of a modification of the structure shown in FIG.  4 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows an apparatus which is constructed and assembled to transport filter rod sections (hereinafter filters)  7  of unit or multiple unit length, e.g., double unit or quadruple unit length. The apparatus comprises a sender  1 , a receiving station  3  (e.g., a station accommodating a machine known as FILTROMAT which is distributed by the assignee of the present application), and a pneumatic conveyor  2  which defines an elongated path extending from the sender  1  to the receiving station  3  and serving to guide successive filters  7  lengthwise in the direction indicated by the arrows  33 . FILTROMAT is a machine which is designed to supply or convey filters to consuming or processing machines, e.g., to filter tipping machines wherein tobacco smoke filters of selected lengths are united with plain cigarettes, cigars or cigarillos to form therewith filter cigarettes, cigars or cigarillos of desired length. 
     The sender  1  comprises a horizontal rotary drum-shaped conveyor  4  (hereinafter drum) having axially parallel peripheral flutes  6  separated from each other by elongated ridges or ribs  9  and communicating with suction ports  8  in certain angular positions to attract and transport discrete filters  7  sideways from a source  12  toward positions of alignment with the inlet of the pneumatic conveyor  2  (hereinafter conduit for short). 
     The drum  4  can receive torque from a horizontal shaft  11  which is rotatable relative to two spaced-apart sleeve-like bearing members  14 ,  16  and is driven by a suitable prime mover (e.g., an electric motor), not shown. Successive ridges  9  of the drum  4  can cooperate with a mobile sealing member  13  to ensure predictable optimum axial propulsion of successive filters  7  arriving to positions for abrupt advancement into the inlet of the conduit  2 . 
     The illustrated source  12  is an upright chute or duct which receives filters from one or more makers and admits successive filters sideways into oncoming flutes  6  at a location B. The location of axial transfer of filters  7  is from their flutes  6  into the inlet of the conduit  2  is shown at C. The conduit  2  of FIGS. 1 to  4  includes a first stationary section which is connected with the sender  1  in the region of the bearing member  14 , a second stationary section having a discharge end located at the receiving station  3 , and a mobile intermediate section  36  between the two stationary sections and rather closely adjacent the sender  1 . As indicated by the left-hand arrow  33  of FIG. 1, the mounting and the operation of the conduit  2  are such that successive filters  7  arriving from the source  12  are propelled upwardly, at least in the section  36 . 
     The aforementioned sealing member  13  is movable between the illustrated raised (sealing) position, which it assumes during propulsion of a filter  7  from its flute  6  into the conduit  2 , and a lowered or retracted position in which the parts  4 ,  13  define an arcuate clearance  17 . The upper side of the sealing member  13  constitutes a concave surface having a radius of curvature complementary to that of the periphery of the drum  4 . The concave surface of the sealing member  13  can abut the adjacent convex surfaces of the bearing members  14 ,  16  in such a way that the elongated surfaces (top lands) at the radially outermost portions of the ridges  9  occupying the location C do not actually contact the sealing member  13 . 
     The drive shaft  11  for the drum  4  extends axially beyond at least one of the bearing members  14 ,  16  and is journalled, without radial play, in stationary walls (not shown). 
     The reference characters  18  denote tensioning crossheads which fixedly connect the bearing members  14 ,  16  with a preferably plate-like support, not shown. Such support further serves to guide a carrier  15  for the sealing member  13  as well as to mount two compressed-air pistons  19  which are utilized to move the sealing member  13  and its carrier  15  up and down between their operative and retracted positions. The illustrated mounting of the sealing member  13  for vertical movement renders it possible to highly reliably establish a clearance  17  of predetermined (optimum) width; such clearance is established at an end face and serves to ensure evacuation of air (at the location C) between the drum  4  and the adjacent surface of the bearing member  14 . 
     The sender  1  is further provided with means for supplying into the flutes  6  a pressurized gaseous fluid (normally compressed air) which serves to expel the filter  7  at the location C lengthwise into the inlet of the conduit  2 . To this end, the drum  4  comprises a flangelike control member  22  which is provided with elongated air passages  23 , one for each of the flutes  6 . Furthermore, the carrier  15  is provided with a transverse bore  24  which is arranged to communicate with a transverse bore  27  of the sealing member  13 . The bore  27  is located between two sealing rings  26  installed between the sealing member  13  and the carrier  15 . 
     The end portions of the pistons  19  are provided with or constitute heads  28  which extend through the carrier  15 . The end faces of the heads  28  bear midway upon the sealing member  13 , and these heads are located within the carrier  15  and are coupled thereto with a predetermined radial play. 
     The bearing member  14  is adjacent the location C and has a sealing surface  31  (this surface contacts the sealing member  13 ) as well as an axially parallel discharge opening  32  which registers with the inlet of the conduit  2  and serves to direct successive filters  7  into such inlet. In order to ensure that successive filters  7  will readily advance along and beyond the edges of the sealing surface  31 , there is provided a ramp  34  which slopes upwardly toward the sealing surface  31  (as seen in the direction, indicated by the right-hand arrow  33 , of propulsion of filters  7  into the conduit  2 ); such ramp is machined into the adjacent supporting and sealing surface of the sealing member  13 . 
     The section  36  of the conduit  2  is adjacent the latter&#39;s inlet, and its details are shown in FIGS. 2 and 3. This section extends from a lower level to an upper level along an arc of less than 180° (the illustrated arc matches or approximates 90°) and forms part of the mobile module  38 . The latter further includes an arcuate part  37  which is or which can be designed and mounted to prevent the section  36  of the conduit  2  from changing its curvature so that such section can be repeatedly connected to and disconnected from the adjacent (straight or substantially straight) additional sections of the conduit  2  by any suitable fastener means. The section  36  can be integrated into the adjacent. Sections of the conduit  2  without departing from the spirit of the invention. 
     The convex underside of the section  36  is provided with an arcuate guide  39  which is located beneath the arcuate part  37  and defines a concave surface for lengthwise advancement of successive filters  7  upwardly and toward the receiving station  3 . The guide  39  is flanked by arcuate openings (such as slots) serving to establish communication between the interior of the section  36  and an adjacent chamber  41  which gathers loose solid particles being expelled from the path for the filters  7 . Such expulsion can take place in part under the action of pressurized gaseous fluid which is used to propel filters  7  toward the receiving station  3 , and in part under the action of centrifugal force. 
     The lower portion of the convex underside of the section  36  is overlapped by a cover  43  which prevents pressurized fluid from flowing full blast into the chamber  41 . At least the major portion ( 42 ) of the cover  43  is or can be made of a suitable resilient metallic sheet material, and the upper end portion  44  of the cover constitutes a suitably bent deflector or lug which serves to establish an optimum flow of gaseous fluid between the adjacent portions of the chamber  41  and the portion of the path defined by the section  36 . The sheet metal part  42  of the cover  43  is preferably precurved (preshaped) in the manufacturing plant so that its underside (which faces the chamber  41 ) exhibits a convex shape. 
     The lower part of the section  36  is provided with an outlet  46  for intermittent or more or less continuous evacuation of intercepted and gathered solid particles from the chamber  41 . FIG. 2 shows one embodiment of the outlet  46 ; the latter defines an upright compartment  47  with a first manually operable valve  48  at the upper end and a second manually operable valve  49  at the lower end. 
     In the embodiment of FIG. 5, the valves  48 ,  49  are opened automatically (when necessary or at preselected intervals), e.g., as a function of time. To this end, the outlet  46  of FIG. 5 employs two fluid-operated cylinder-and-piston units  50 ,  51 , one for each of the respective (automated) valves  48 ,  49 . 
     The exact construction of the parts constituting the sender  1  forms no part of the present invention. As a rule, the operation of this sender is fully automated because it is expected to furnish several thousand filters per minute. 
     The mode of operation of the improved apparatus, and particularly of the parts shown in detail in FIGS. 2-4 and  5 , is as follows: 
     In order to propel a filter  7  into the conduit  2  upstream of the section  36 , the mobile sealing member  13  is lifted from its lower end position to the illustrated raised or operative position (for example, the sealing member can be moved to its lower end position, at fixed or arbitrary intervals, for the purpose of inspection and/or cleaning) When the sealing member  13  reaches the raised position of FIG. 1, the extent of movability of the heads  28  of the pistons  19  relative to the carrier  15  (i.e., the play of the aforediscussed loose connection between the carrier  15  and the heads  28 ) is such that the sealing ring(s)  26  is(are) stressed between the sealing member  13  and the carrier. Consequently, the crossheads  18  are in the process of taking up the compressive and bending stresses being applied to the bearing members  14  and  16 . The corresponding system of the sender  1  shown in FIG. 1 is then under requisite stress. However, and since the diameter of the drum  4  is relatively small, there is established the aforediscussed predetermined clearance between the periphery of the drum and the sealing member  13 ; this allows for the friction-and hence wear-free operation of the sender  1 . 
     When the prime mover for the drive shaft  11  is on, successive flutes  6  of the continuously rotating drum  4  accept discrete filters  7  from the source  12  at the location B and deliver discrete filters at the location C. The drum  4  is or can be driven at a constant speed, also during those stages of operation of the sender  1  when the filters  7  are in the process of being actually propelled from their flutes  6  axially and into the inlet of the conduit  2 . Actual propulsion takes place when a flute  6  registers with the bore  32  of the bearing member  14 ; a blast of pressurized pneumatic fluid is then free to flow from the transverse bore  24  of the carrier  15 , into the transverse bore  27  of the sealing member  13 , thence into the air passage  23  then disposed at the location C, and ultimately into the aligned or registering flute  6 . The thus admitted blast or jet of pressurized gaseous fluid expels the filter  7  from its flute  6  in the direction of the right-hand arrow  33  shown in FIG.  1  and into the inlet of the conduit  2 . The ramp  34  is effective to further ensure entry of an axially advancing filter  7  from its flute  6  into the conduit  2 . 
     Solid particles (such as charcoal granules) which are normally confined in the tubular envelope of a filter  7  (such granules can be distributed in the rod-like filler of the filter) are likely to escape from their envelopes (such envelopes can be made, for example, of cigarette paper) due to repated changes of direction (from sideways to lengthwise and/or vice versa), stoppages, acceleration and/or deceleration of a filter on its way into and through the source  12  and thence toward and into the inlet of the conduit  2 . The thus obtained stray particles tend to clog the conduit  2  and/or to adhere to (and to thus cause coloration and/or other types of contamination of) the external surfaces of the filters  7 . Therefore, there exists an urgent need for predictable, reliable, timely, simple and reproducible evacuation of loose solid particles from the path between the sender  1  and the receiving station  3 . Such evacuation takes place in the region of the arcuate part  37  where the stray solid particles are acted upon by centrifugal force along an arc of 90° and are thus propelled into the chamber  41 . 
     The cover  43  prevents solid particles from migrating out of the chamber  41  and back into the section  36  of the conduit  2 . The deflector  44  establishes a fluid flow which actually draws loose solid particles from the interior of the section  36  into the chamber  41 , namely a downwardly oriented fluid flow. 
     Solid particles which gather in the lower portion of the chamber  41  can be caused to descend into the compartment  47  in response to manual opening of the valve  48  shown in FIG.  2 . Once the valve  48  is closed again, the person in charge opens the valve  49  to permit the accumulated solid particles to descend from the compartment  47  into a collecting receptacle (not shown) or onto or into a suitable conveyor, or to be caused to advance to another destination, e.g., back into the respective magazine of the machine which is utilized for the making of filters containing particles of charcoal and/or other material(s). 
     The outlet  46  should be put to use as frequently as is necessary to ensure that the pressure of conveying fluid in the conduit  2  cannot drop below a minimum acceptable (lower threshold) value. 
     The automatic arrangement  50 ,  51  of FIG. 5 which can be utilized in lieu of manually operated valves  48 ,  49  shown in FIG. 2 can be set up to open the valves  48 ,  49  of FIG. 5 sequentially at preselected intervals or in response to monitoring of the accumulations of solid particles in the compartment  47 . 
     The mobile module  38  Of FIG. 2 can be replaced with a piece of arcuate pipe when the conduit extending from the sender  1  toward the receiving station  3  is set up to deliver a file of filters which are devoid of solid particles. Such module thus contributes to versatility of the improved apparatus. 
     An important advantage of the improved apparatus is that stray solid particles can be evacuated from an upstream section ( 36 ) of the conduit  2 , i.e., in a region where the pressure of the pneumatic fluid is still very high. Such evacuation is possible because loose solid particles advancing toward and into the arcuate section  36  are still being acted upon by a pronounced centrifugal force. 
     Another advantage of the improved apparatus is that evacuation of loose solid particles from the section  36  of the conduit  2  into the collecting chamber  41  does not entail a pronounced drop of pressure of the fluid flow which is utilized to propel successive filters lengthwise from the sender  1  (or an equivalent sender) into the receiving station  3 . 
     A further advantage of the improved apparatus is that the evacuation of collected solid particles (including dust) from the chamber  41  (via outlet  46 ) constitutes a simple and time-saving procedure which can be carried out while the conduit  2  continues to deliver filters to the station  3 . 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of the above outlined contribution to the art of transporting filter rods and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.