Turret bagger
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to automatic bagging machines. 
     2. Prior Art 
     U.S. Pat. No. 3,789,573 issued to Jasper R. Crabb discloses an automatic bagging machine including one set of bag-holding and spreading arms which set is reciprocated between a station where bags are picked up and filled and a station where bags are tied. The problems with that bagging machine are: only one set of reciprocating arms is provided so that the pickup and filling station remains idle while a picked-up and filled bag is being moved to the tying station, while such bag is being tied at the tying station and while the arms are being moved back to the pickup and filling station; no auxiliary mechanism is provided to guide articles into a bag which has been spread at the pickup and filling station; and no mechanism is provided for steadying a filled bag as it is moved from the pickup and filling station to the tying station. Consequently, the bagging machine of U.S. Pat. No. 3,789,573 is slow in that: both stations are not active at the same time; rapid insertion of articles into a spread bag is not possible; and a filled bag must be moved slowly from the pickup and filling station to the tying station to deter violent swaying. 
      SUMMARY OF THE INVENTION 
     It is the principal object of the present invention to provide an automatic bagging machine which sequentially picks up, fills and ties bags rapidly. 
     Further to this object, it is an object to provide such a machine in which a plurality of stations for picking up, filling and tying bags perform their respective functions substantially simultaneously. 
     Further to the principal object, it is an object to provide auxiliary mechanism to spread bags at a bag-filling station and to guide articles into spread bags so that such bags may be filled rapidly. 
     Further to the principal object, it is an object to provide drive mechanism to shift bags quickly from one bagging machine station to another bagging machine station. 
     Further to the principal object, it is an object to provide mechanism for steadying a filled bag as it is moved from a bag-filling station to a bag-tying station. 
     Further to the principal object, it is an object to provide mechanism for decelerating holding and spreading arms as they approach a bagging machine station. 
     The foregoing objects can be accomplished by providing an automatic bagging machine including a bag-pickup station, a bag-filling station and a bag-tying station spaced from one another circumferentially around an orbit. Drive mechanism incrementally shifts each of several sets of bag-holding and spreading arms sequentially from the pickup station to the filling station, then to the tying station and back to the pickup station. Auxiliary spreading mechanism spreads bags at the filling station and guides articles into the spread bags. Steadying mechanism reciprocates between the filling station and the tying station and braking mechanism decelerates the holding and spreading arms as they approach each of the bagging machine stations. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan of an automatic bagging machine in accordance with the present invention. 
     FIG. 2 is a detail of the drive mechanism of the bagging machine shown in FIG. 1, some parts being broken away, and FIG. 3 is a section taken on line 3--3 of FIG. 2 with some parts broken away. 
     FIG. 4 is a detail elevation of an automatic bagging machine in accordance with the present invention including decelerating mechanism, some parts being shown in section and some parts being broken away. 
     FIG. 5 is a plan of the bagging machine of FIG. 4, some parts being shown in section and some parts being broken away. 
     FIG. 6 is a detail elevation of the filling station of the bagging machine shown in FIG. 1 with some parts broken away and some parts shown in section, and FIG. 7 is a corresponding detail showing parts in different positions. 
     FIG. 8 is a side elevation of the pickup station of the bagging machine of FIG. 1, some parts being broken away; FIG. 9 is an end elevation of such pickup station, some parts being broken away; and FIG. 10 is an enlarged detail end elevation of such pickup station showing parts in different positions. 
    
    
     DETAILED DESCRIPTION 
     As shown in FIG. 1, an automatic bagging machine in accordance with the present invention includes a bag-pickup station P, a bag-filling station F, and a bag-tying station T spaced equidistant from one another circumferentially around an orbit. A central vertical shaft 1 carries a turret including several sets of radial bag-holding and spreading arms 2 spaced angularly to locate one set of such arms over each of the bagging machine stations. The construction of the pickup station is substantially identical to the construction of the &#34;bag feeding mechanism&#34; disclosed in U.S. Pat. No. 3,789,573. Further, the construction of each set of holding and spreading arms 2 is similar to the construction of the &#34;bag holding mechanism&#34; described in that patent in that each set includes rocking mechanism for vertical swinging about a horizontal axis. Bag-engaging spades carried by the swinging ends of such arms are lowered into the upper end of a bag partially opened by the bag feeding mechanism. Spreading mechanism performs spreading and closing operations, respectively, prior to and following the filling of a bag. Clamping mechanism includes leading and trailing clamping devices mounted on the bag-engaging spades for holding a bag. Each of the above features operates substantially as disclosed in U.S. Pat. No. 3,789,573. The construction of the tying station T may be substantially identical to the tying device disclosed in U.S. Pat. No. 3,789,573, but any other suitable tying device may be used. Further, the construction of filling station F does not constitute part of the present invention except for the auxiliary spreading and guiding mechanism which is further described below. 
     In accordance with the present invention, a set of bag-holding and spreading arms 2 picks up and spreads a bag at pickup station P. Central shaft 1 is rotated to shift such set of arms from the pickup station to filling station F. Auxiliary spreading mechanism 3 further spreads the picked-up bag and guides articles into such bag. For example, such articles may be supplied by a chute 4. The auxiliary spreading mechanism releases the bag, whereupon central shaft 1 is again rotated to shift the filled bag to tying station T where the bag is tied and dropped onto a discharge conveyor 5. Central shaft 1 is again rotated to shift the holding and spreading arms back to the pickup station. Since several sets of arms are provided, the bagging machine stations perform their respective functions substantially simultaneously, that is, while a bag is being picked up at station P, a bag which has already been picked up is being filled at station F and a bag which has been filled is being tied at station T. 
     Drive mechanism for incrementally rotating central shaft 1 to rotate the turret and shift each set of holding and spreading arms from one station to the next station is shown in FIGS. 2 and 3. Suitable support structure 6 carries a pneumatic cylinder 7 which includes a reciprocating plunger 8. The plunger is attached to a chain 9 which connects central and outer sprockets 10 and 11, respectively. Conventional clutch mechanism 12 is provided to convert the reciprocating motion of central sprocket 10 into the unidirectional incremental turning of central shaft 1. Each time plunger 8 is extended from the dotted line position of FIG. 2 to the solid line position of that figure, the central shaft is rotated through an angle sufficient to shift each set of holding and spreading arms from one of the bagging machine stations to the next station. Each set of holding and spreading arms remains substantially stationary over one of the bagging machine stations as plunger 8 reciprocates back to its retracted position. 
     As seen in FIGS. 4 and 5, to decelerate the holding and spreading arms as they approach the various stations of the bagging machine, and to hold such arms stationary over the stations as plunger 8 is retracted, two caliper brakes 13 and 14 may be provided. Each brake is operable to grip a brake disk 15 carried by and rotated conjointly with central shaft 1 above clutch 12. Brake 14 is stationary because it is mounted on the bagging machine support structure. Brake 13 is mounted for swinging movement relative to the central shaft and the support structure by a collar 16 receiving the central shaft above brake disk 15, and a support arm 17 which extends radially outward from the collar. The degree of movement of brake 13 is limited by a resilient member, such as a spring 18 extending between the stationary bagging machine support structure and the outer end of support arm 17. Such movement is also limited by a shock absorber 19 connected between the bagging machine support structure and another arm 20 which extends radially outward from collar 16. 
     As each set of holding and spreading arms 2 nears a bagging machine station, brake 13 is actuatd to grip brake disk 15 firmly. Spring 18 and shock absorber 19 cooperate to decelerate the brake disk, the central shaft and the holding and spreading arms carried by the central shaft. When the holding and spreading arms are in position over the bagging machine station, brake 14 is actuated to hold the central shaft against rotation while plunger 8 is reciprocated back to its retracted position and while the picking up, filling and tying operations are being performed at the bagging machine stations. 
     As best seen in FIGS. 6 and 7, auxiliary spreading mechanism 3 is located at filling station F opposite article chute 4. Such mechanism is mounted on the bagging machine support structure 6 and includes a vertically extending support plate 21 located in a radial plane of the turret. The radially inner end of a pneumatic cylinder 22 is attached to the support plate by a horizontal pivot 23. Air in such cylinder drives a plunger 24 which is pivotally attached to one point of a bell crank 25. The other two points of the bell crank are pivotally attached, respectively, to the support plate and to a spreading and guiding member 26 which includes a generally vertical spreading and guiding face 27. A tension spring 28 is connected between spreading and guiding member 26 and a pin 29 extending from support plate 21. Such pin is received in a generally horizontal slot 30 in the radially inner end of the spreading and guiding member. The force of spring 28 on member 26 holds the slot against the pin to prevent clattering. 
     When plunger 24 is extended, as shown in dotted lines in FIG. 6, spreading and guiding member 26 is swung upward and inward out of the way of holding and spreading arms 2 which are advanced toward the filling station. When such arms are in position adjacent to the article chute, plunger 24 is retracted to swing the spreading and guiding member downward to hook the bag held by arms 2 and to draw the inner lip of the bag radially inward. Articles a may be rapidly discharged from chute 4 because the guiding face 27 of member 26 acts as a backstop to guide such articles into the spread bag. When the bag is full, plunger 24 is extended to swing spreading and guiding member 26 upward to release the bag and inward to the dotted line position of FIG. 6. 
     As described above, once the auxiliary spreading mechanism releases a filled bag, the holding and spreading arms are shifted to tying station T carrying the filled bag with them. Since it is desirable to shift the filled bag quickly, steadying mechanism, best seen in FIGS. 1 and 3, is provided. An upper support arm 31 extends radially of the turret outward from the central drive sprocket 10. A lower support arm 32 extends radially outward from the upright shaft carrying the drive sprocket. The outer end portions of the support arms carry a steadying hand 33 which is engageable with the filled bag. As drive mechanism plunger 8 is extended to shift a filled bag from the bag-filling station to the bag-tying station, the steadying hand follows the filled bag. As plunger 8 is retracted such hand is swung back behind the filling station to a position for following the next filled bag as it is shifted from the filling station to the tying station by extension of the plunger. Consequently, filled bags can be shifted quickly withut violent swinging. 
     Once a filled bag has been shifted to the tying station and tied, it is dropped onto discharge conveyor 5 and the holding and spreading arms are shifted to the pickup station. However, as best seen in FIGS. 8, 9 and 10, such arms must be lifted to clear the mechanism holding a pack of bags b. Suitable control mechanism, such as that described in U.S. Pat. No. 3,789,573, lowers the bag spreading arms into a partially opened bag, as shown in FIG. 10, and such bag is ready for spreading and shifting to the filling station. 
     A bagging machine in accordance with the present invention will pick up, fill and tie bags more rapidly than known machines because separate pickup, filling and tying stations are provided, and all of the stations perform their respective functions at the same time. Further, the bagholding and spreading arms may be swung quickly because the braking mechanism decelerates the arms as they approach a bagging machine station and because filled bags are steadied as they are shifted from the filling station to the tying station. In addition, the filling operation can be accomplished almost as quickly as the pickup or tying operation because auxiliary spreading and guiding mechanism is provided.