Automatic tying apparatus

Claim 2

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, and bundle clamping means mounted on said support means proximate said tying station, said clamping means comprising a normally open pair of opposed clamping jaws located generally on opposite sides of the path of travel of said bundles, and cyclically operable jaw drive means connected to at least one of said jaws for closing said jaws into clamping engagement against said opposite sides of each bundle when the bundle is at the tying station and opening the jaws as said bundle leaves the tying Station and the next bundle enters the tying station, said jaws being movable in the direction and at substantially the speed of movement of each bundle while the jaws are in clamping engagement therewith.

Claim 3

Bundle tying apparatus as defined in claim 1, wherein said tying mechanism is supported on carriage means mounted for reciprocal sliding movement in the longitudinal direction of said conveyor means, and carriage drive means connected to said carriage means and synchronized with said conveyor means for applying said reciprocal sliding movement to said carriage means, said carriage drive means moving said carriage means in the same direction as the movement of said conveyor means proximate the time said knotting is effected, at least one of said jaws being supported on said carriage means for reciprocal movement therewith in the longitudinal direction.

Claim 4

Bundle tying apparatus as defined in claim 2, wherein said driven jaw is supported on said carriage means.

Claim 5

Bundle tying apparatus as defined in claim 3, wherein the other jaw is supported on said support means independent of said carriage means and comprises a chain synchronized with said conveyor means.

Claim 6

Bundle tying apparatus as defined in claim 3, wherein both of said jaws are supported on said carriage means.

Claim 7

Bundle tying apparatus as defined in claim 3, wherein said driven jaw comprises a longitudinally arranged support bar and an elongated jaw body longitudinally slidably mounted thereon, said body being rearwardly biased on said bar, and being forwardly slidable on the bar against said biasing to accommodate lost motion between the carriage means and the bundle.

Claim 8

Bundle tying apparatus as defined in claim 1, wherein said tying mechanism includes pneumatically operable drive means, said jaw drive means also being pneumatically operable and being coupled to said tying mechanism drive means for synchronization therewith.

Claim 9

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, and energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said tying mechanism including pneumatically operable drive means having a rotatable drive shaft coupled to the tying mechanism, and pneumatic cylinder means operatively connected to said drive shaft through clutch means, said pneumatic cylinder means being operable in response to said energizing means to apply limited rotational movement to said drive shaft so as to drive the tying mechanism through a single cycle of operation.

Claim 10

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, and energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said tying mechanism including pneumatically operable drive means having a rotatable drive shaft coupled to the tying mechanism, and pneumatic cylinder means operatively connected to said drive shaft through clutch means, said pneumatic cylinder means being operable in response to said energizing means to apply limited rotational movement to said drive shaft so as to drive the tying mechanism through a single cycle of operation.

Claim 11

Bundle tying apparatus as defined in claim 8, wherein the operative connection between said pneumatic cylinder means and said drive shaft includes a pull chain connected to the pneumatic cylinder means, a sprocket coaxial with said drive shaft and over which said pull chain is engaged, and an overrunning clutch connection between said sprocket and said drive shaft.

Claim 12

Bundle tying apparatus as defined in claim 8, which includes a cam wheel having a recess therein mounted on said drive shaft, and cam follower means spring-biased into engagement with said cam wheel, engagement of said can follower means in said cam wheel recess stopping movement of said drive shaft and hence of said tying mechanism at the end of a tying cycle.

Claim 13

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said tying mechanism being supported on carriage means mounted for reciprocal sliding movement in the longitudinal direction of said conveyor means, and carriage drive means connected to said carriage means and synchronized with said conveyor means for applying said reciprocal sliding movement to said carriage means, said carriage drive means moving said carriage means in the same direction as the movement of said conveyor means proximate the time said knotting is effected.

Claim 14

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said tying mechanism being supported on carriage means mounted for reciprocal sliding movement in the longitudinal direction of said conveyor means, and carriage drive means connected to said carriage means and synchronized with said conveyor means for applying said reciprocal sliding movement to said carriage means, said carriage drive means moving said carriage means in the same direction as the movement of said conveyor means proximate the time said knotting is effected.

Claim 15

Bundle tying apparatus as defined in claim 11, wherein said carriage drive means comprises cam means on said support means driven from the same power source as said conveyor means and cam follower means on said carriage means.

Claim 16

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will know said string portions together proximate said trailing of the bundle as the bundle passes said station, said tying mechanism including electrically operable drive means, and said energizing means including electrical switch means operatively connected to said drive means and disposed partly in said path of travel so as to be directly actuated by the respective bundles, said switch means including microswitch means directly actuated by the respective bundles, and cycling relay means energized by said microswitch means, said cycling relay means controlling both the initiation and the completion of said cycle of operation of the tying mechanism.

Claim 17

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will know said string portions together proximate said trailing of the bundle as the bundle passes said station, said tying mechanism including electrically operable drive means, and said energizing means including electrical switch means operatively connected to said drive means and disposed partly in said path of travel so as to be directly actuated by the respective bundles, said switch means including microswitch means directly actuated by the respective bundles, and cycling relay means energized by said microswitch means, said cycling relay means controlling both the initiation and the completion of said cycle of operation of the tying mechanism.

Claim 18

Bundle tying apparatus as defined in claim 13, wherein said drive means includes a continuously running electric motor, a normally disengaged magnetic clutch and a normally engaged solenoid-operated brake, said cycling relay means, upon energization thereof, energizing said brake solenoid to release said brake and energizing and thereby engaging said magnetic clutch.

Claim 19

Bundle tying apparatus as defined in claim 13, whErein said cycling relay includes a holding circuit that is closed upon energization of said cycling relay to hold the cycling relay in its energized state through said cycle of operation of the tying mechanism and normally closed cam-operated switch means in said holding circuit which is opened by a cam in said drive means to define completion of said cycle of operation of the tying mechanism.

Claim 20

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, and energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said first tying element comprising a knotter and said second tying element comprising a tying arm having said string fed from the free end thereof, said tying arm being mounted for reciprocal swinging movement during a cycle of operation of the tying mechanism, the free end thereof swinging from an inoperative position spaced from said path forwardly in the path immediately behind a bundle to an operative knotting position engaged with said knotter, and then swinging back out of the path to said inoperative position, said knotter including a bobbin that is quickly movable to effect tying of a knot upon engagement of said free end of said tying arm with said knotter, and limiting bar means on the knotter engageable by said tying arm to limit the extent of penetration of the tying arm into the knotter and thereby prevent the tying arm from impacting against the bobbin.

Claim 21

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, and energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said first tying element comprising a knotter and said second tying element comprising a tying arm having said string fed from the free end thereof, said tying arm being mounted for reciprocal swinging movement during a cycle of operation of the tying mechanism, the free end thereof swinging from an inoperative position spaced from said path forwardly in the path immediately behind a bundle to an operative knotting position engaged with said knotter, and then swinging back out of the path to said inoperative position, said knotter including a bobbin that is quickly movable to effect tying of a knot upon engagement of said free end of said tying arm with said knotter, and limiting bar means on the knotter engageable by said tying arm to limit the extent of penetration of the tying arm into the knotter and thereby prevent the tying arm from impacting against the bobbin.

Claim 22

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanisms being cyclically operable to knot said string portions together and energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said first tying element comprising a knotter and said second tying element comprising a tying arm having said string fed from the free end thereof, said tying arm being mounted for reciprocal swinging movement during a cycle of operation of the tying mechanism, the free end thereof swinging from an inoperative position spaced from said path forwardly into the path immediately behind a bundle to an operative knotting position engaged with said knotter, and then swinging back out of the path to said inoperative position, said support means including an elongated, generally horizontaL surface defining said path of travel at least in part, said conveyor means including a series of pusher members adapted to push said bundles sequentially along, said surface, said knotter being located generally below said surface with said surface apertured proximate the knotter to receive the tying arm, and said tying arm being pivotally mounted above said surface with the free end thereof swingable downwardly and forwardly behind each bundle into engagement with the knotter, said conveyor means including a continuous chain loop disposed principally below said surface and having an upper section thereof disposed adjacent and generally parallel to said surface, said surface having a longitudinally extending slot therein, and said pusher members comprising pusher posts projecting outwardly from said chain loop so that the posts on said upper section of the chain, project upwardly through said slot and above said surface, said conveyor means also including a continuous belt loop having an upper section that is generally parallel to said upper section of the chain loop but is offset downstream therefrom so that part of said belt section is side-by-side with a downstream end portion of said chain section, said belt having a materially greater lineal speed than said chain, whereby bundles which have been tied at said tying station and are being moved by said pusher posts near the downstream end of said chain section are engaged by said belt section and moved downstream away from their respective chain pusher posts to provide clearance for said posts to turn downwardly through said slot at the downstream end of said chain section.

Claim 23

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanisms being cyclically operable to knot said string portions together and energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said first tying element comprising a knotter and said second tying element comprising a tying arm having said string fed from the free end thereof, said tying arm being mounted for reciprocal swinging movement during a cycle of operation of the tying mechanism, the free end thereof swinging from an inoperative position spaced from said path forwardly into the path immediately behind a bundle to an operative knotting position engaged with said knotter, and then swinging back out of the path to said inoperative position, said support means including an elongated, generally horizontaL surface defining said path of travel at least in part, said conveyor means including a series of pusher members adapted to push said bundles sequentially along, said surface, said knotter being located generally below said surface with said surface apertured proximate the knotter to receive the tying arm, and said tying arm being pivotally mounted above said surface with the free end thereof swingable downwardly and forwardly behind each bundle into engagement with the knotter, said conveyor means including a continuous chain loop disposed principally below said surface and having an upper section thereof disposed adjacent and generally parallel to said surface, said surface having a longitudinally extending slot therein, and said pusher members comprising pusher posts projecting outwardly from said chain loop so that the posts on said upper section of the chain, project upwardly through said slot and above said surface, said conveyor means also including a continuous belt loop having an upper section that is generally parallel to said upper section of the chain loop but is offset downstream therefrom so that part of said belt section is side-by-side with a downstream end portion of said chain section, said belt having a materially greater lineal speed than said chain, whereby bundles which have been tied at said tying station and are being moved by said pusher posts near the downstream end of said chain section are engaged by said belt section and moved downstream away from their respective chain pusher posts to provide clearance for said posts to turn downwardly through said slot at the downstream end of said chain section.

Claim 24

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by bundle first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said first tying element comprising a knotter and said second tying element comprising a tying arm having said string fed from the free end thereof, said tying arm being mounted for reciprocal swinging movement during a cycle of operation of the tying mechanism, the free end thereof swinging from an inoperative position spaced from said path forwardly into the path immediately behind a bundle to an operative knotting position engaged with said knotter, and then swinging back out of the path to said inoperative position said support means including an elongated, generally horizontal surface defining said path of travel at least in part, said conveyor means including a series of pusher members adapted to push said bundles sequentially along said surface, said knotter being located generally below said surface with said surface apertured proximate the knotter to receive the tying arm, said tying arm being pivotally mounted above said surface with the free end thereof swingable downwardly and forwardly behind each bundle into engagement with the knotter, a pair of spaced, longitudinally arranged guide rails extending upwardly from said surface so as to further define said path of travel, and a pair of anticurling ears mounted proximate said tying station adjacent the respective guide rails spacEd upwardly from said surface, said ears being biased toward operative positions wherein they project generally horizontally inwardly from said guide rails over said surface to hold bundles thin enough to fit under the ears down generally flat against said surface during tying, said ears having respective cam surfaces thereon engageable by side portions of bundles too thick to pass under the ears for camming said ears out of the way of such bundles.

Claim 25

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by bundle first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together, energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, said first tying element comprising a knotter and said second tying element comprising a tying arm having said string fed from the free end thereof, said tying arm being mounted for reciprocal swinging movement during a cycle of operation of the tying mechanism, the free end thereof swinging from an inoperative position spaced from said path forwardly into the path immediately behind a bundle to an operative knotting position engaged with said knotter, and then swinging back out of the path to said inoperative position said support means including an elongated, generally horizontal surface defining said path of travel at least in part, said conveyor means including a series of pusher members adapted to push said bundles sequentially along said surface, said knotter being located generally below said surface with said surface apertured proximate the knotter to receive the tying arm, said tying arm being pivotally mounted above said surface with the free end thereof swingable downwardly and forwardly behind each bundle into engagement with the knotter, a pair of spaced, longitudinally arranged guide rails extending upwardly from said surface so as to further define said path of travel, and a pair of anticurling ears mounted proximate said tying station adjacent the respective guide rails spacEd upwardly from said surface, said ears being biased toward operative positions wherein they project generally horizontally inwardly from said guide rails over said surface to hold bundles thin enough to fit under the ears down generally flat against said surface during tying, said ears having respective cam surfaces thereon engageable by side portions of bundles too thick to pass under the ears for camming said ears out of the way of such bundles.

Claim 26

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, second conveyor means on said support means oriented generally normal to said first mentioned conveyor means, said second conveyor means being located with respect to said first mentioned conveyor means so that once-tied bundles are delivered from the downstream end of said first mentioned conveyor means onto said second conveyor means from one side thereof whereby said once-tied bundles are moved sequentially by said second conveyor means with the string tie on each bundle disposed generally normal to the direction of movement, a second tying station on said support means adjacent to said second conveyor means and past which said once-tied bundles are moved by said second conveyor means, second tying mechanism proximate said second station comprising a pair of tying elements located generally on opposite sides of the path of travel of said bundles as they are moved by said second conveyor means, second tying mechanism proximate said second station comprising a pair of tying elements located generally on opposite sides of the path of travel of said bundles as they are moved by said second conveyor means, a second source of supply of string fed through one of said pair of elements and retained by the other of said pair to extend across said last mentioned path in front of each bundle whereby the leading edge of each bundle engages said second string and movement of the bundle causes portions of said second string to be doubled back along respective opposite sides of the bundle, generally at right angles to said first and second portions of said first mentioned string, to the trailing edge of the bundle, said second tying mechanism being cyclically operable to knot said second string portions together, second energizing means for initiating a cycle of operation of said second tying mechanism according to bundle position in said last mentioned path so that said second tying mechanism will knot said second string portions together proximate said trailing edge of the bundle as the bundle passes said second station, and a cover plate adapted to extend over a portion of said second conveyor means generally in line with said first mentioned conveyor means, said cover plate being movable between a covering position over said portion of the second conveyor means when a bundle is being delivered thereto from said first mentioned conveyor means wherein said cover plate prevents entanglement of the bundle with said second conveyor means as the bundle moves onto said second convEyor means, and an uncovering position wherein the plate permits engagement of the bundle by said second conveyor means.

Claim 27

Bundle tying apparatus which comprises support means having a tying station thereon, conveyor means on said support means arranged to move a series of bundles sequentially past said tying station, tying mechanism proximate said station comprising first and second tying elements located generally on opposite sides of the path of travel of said bundles, a source of supply of string fed through said second element and retained by said first element to extend across said path in front of each bundle whereby the leading edge of the bundle engages the string and movement of the bundle causes first and second portions of the string to be doubled back along respective opposite sides of the bundle to the trailing edge thereof, said tying mechanism being cyclically operable to knot said string portions together energizing means for initiating a cycle of operation of said tying mechanism according to bundle position in said path so that said tying mechanism will knot said string portions together proximate said trailing edge of the bundle as the bundle passes said station, second conveyor means on said support means oriented generally normal to said first mentioned conveyor means, said second conveyor means being located with respect to said first mentioned conveyor means so that once-tied bundles are delivered from the downstream end of said first mentioned conveyor means onto said second conveyor means from one side thereof whereby said once-tied bundles are moved sequentially by said second conveyor means with the string tie on each bundle disposed generally normal to the direction of movement, a second tying station on said support means adjacent to said second conveyor means and past which said once-tied bundles are moved by said second conveyor means, second tying mechanism proximate said second station comprising a pair of tying elements located generally on opposite sides of the path of travel of said bundles as they are moved by said second conveyor means, second tying mechanism proximate said second station comprising a pair of tying elements located generally on opposite sides of the path of travel of said bundles as they are moved by said second conveyor means, a second source of supply of string fed through one of said pair of elements and retained by the other of said pair to extend across said last mentioned path in front of each bundle whereby the leading edge of each bundle engages said second string and movement of the bundle causes portions of said second string to be doubled back along respective opposite sides of the bundle, generally at right angles to said first and second portions of said first mentioned string, to the trailing edge of the bundle, said second tying mechanism being cyclically operable to knot said second string portions together, second energizing means for initiating a cycle of operation of said second tying mechanism according to bundle position in said last mentioned path so that said second tying mechanism will knot said second string portions together proximate said trailing edge of the bundle as the bundle passes said second station, and a cover plate adapted to extend over a portion of said second conveyor means generally in line with said first mentioned conveyor means, said cover plate being movable between a covering position over said portion of the second conveyor means when a bundle is being delivered thereto from said first mentioned conveyor means wherein said cover plate prevents entanglement of the bundle with said second conveyor means as the bundle moves onto said second convEyor means, and an uncovering position wherein the plate permits engagement of the bundle by said second conveyor means.