US3037535A - Knotter mechanism for automatic wire-tying machine - Google Patents

Description

June 5, 1962 J. J. LINEHAN ETAL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRETYING MACHINE Filed Feb. 10. 1960 14 Sheets-Sheet l UVVE/VTORS JOHN J L l/VEHA/V and EDWARD n. SCHULTZ Attorney June 5, 1962 J. J. LINEHAN ET AL 3, 3 3

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 TTE=E F 1 14 Sheets-Sheet 2 I l I //V VE/VTORS JOHN J Ll/VEHAN and EDWARD W. SCHULTZ 7 Attorney June 5, 1962 J. J. LINEHAN ET AL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 14 Sheets-Sheet 3 Attorney June 5, 1962 J. J. LINEHAN ET AL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 14 Sheets-Sheet. 4

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10. 1960 June 5, 1962 J. J. LINEHAN ETAL 14 Sheets-Sheet 5 22221- F WIT 19- I Attorney June 5, 1962 J. J. LINEHAN ETAL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 14 Sheets-Sheet 6 F247 ETETE llVl/E/VTORS JOHN J. Ll/VEHA/V and ED WARD W. SCHUL 7'2 Attorney June 5, 1962 J. J. LINEHAN ET AL 3, 3

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960- 14 Sheets-Sheet 7 m i? s v k V *1- g a O O 8 g v m o g M N Q N m G g Q N a I l I r m x Q a, I m I & M

()o o K Q, H '3 g Y i), H 3 q; v 1 I 0 F Q) k 0 I O INVENTORS JOHN J. L/NEHA/V and EDWARD M. SCHULTZ TZLEEEI Attorney June 1962 J. J. LINEHAN ET AL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 14 Sheets-Sheet 8 INVENTORS JOHN J L/NEHA/V and EDWARD W. SCHULTZ A from ey June 5, 1962 J. J. LINEHAN ETAL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10. 1960 14 Sheets-Sheet 9 bvi i vmlF F -TYING MACHINE June 5, 1962 J. J. LINEHAN ETAL KNOTTER MECHANISM FOR AUTOMATIC WIRE Filed Feb. 10, 1960 14 Sheets-Sheet 1O flw Attorney June 5, 1962 .1. J. LINEHAN ETAL 3,037,535

'KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 l4Sheets-Sheet 11 //V VE/VTORS JOHN J. L/IVEHA/V and EDWARD H. SCHULTZ A fforpey June 5, 1962 J. J. LINEHAN ET AL 3,037,535

KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE l4 Sheets-Sheet l2 FiledFeb. 10. 1960 FIE-2'25 I /2 IN l/E N TORS JOHN J. L INEHA/V and EDWARD W. SCHULTZ Br Mfl 9125;,

Attorney June 5, 1962 J. J. LINEHAN ETAL KNO'ITER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10, 1960 14 Sheets-Sheet l3 hrs-=25 /.9 1 w )rTiEeES E L k INVENTORS JOHN J. L/IVEHA/V and EDWARD W. SCHULTZ June 5, 1962 J. J. LlNEHAN ETAL KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE Filed Feb. 10. 1960 14 SheetsSheet 14 Flt-E E7 INVENTORS JOHN J. L/IVEHA/V arm EDWARD W. SCHULTZ r waflwu orney United States Patent Ofiice 3,037,535 Patented June 5, 1962 3,037,535 KNOTTER MECHANISM FOR AUTOMATIC WIRE-TYING MACHINE John J. Linehan, Flossmoor, and Edward W. Schultz,

Homewood, Ill., assignors to United States Steel Corporation, a corporation of New Jersey Filed Feb. 10, 196i), Ser. No. 7,833 14 Claims. (Cl. 140115) This invention relates generally to automatic machines for applying a Wire tie or strapping around a package. One example of this type of machine is shown in Vining et al. Patent No. 2,416,859. In the operation of such machine, a supply wire, from which a tie is to be made, is fed around a guide track in the form of a loop, with the ends of the tie overlapped in the slot of a twister pinion. Then when a tie is to be applied to a package, the package is placed within the guide track and the wire is retracted to draw the tie taut around the package. The overlapped ends are then twisted together by the pinion and the tie is cut free from the supply wire and ejected from the slot.

The present invention relates more particularly to the knotter mechanism or means for forming the knot in the tie and specifically to a knotter mechanism movable from and to the tying position so that ejection of the twisted knot is unnecessary.

The knotter of our invention, as herein described and claimed, may be employed in any known automatic tying machine of the same general type as the Vining et a1. machine. Details of parts other than the knotter are not included herein.

It is, accordingly, an object of our invention to provide an improved knotter mechanism adapted to be incorporated in an automatic wire-tying machine for twisting into a knot the overlapped ends of a wire tie looped around a package after the wire has been drawn taut around the package, including means for cutting and ejecting the completed tie after the knot has been formed.

It is a further object of the invention to provide a knotter mechanism including a movably mounted slotted twister pinion and means for moving it away from the tie wire after the knot has been formed.

It is another object of the invention to provide a knotter mechanism wherein the twister pinion and its driving means are mounted in a pivotally supported housing with cam means for pivoting the housing toward and away from the tie Wire in proper sequence during the wire tying or strapping cycle.

It is another object of the invention to provide a knotter mechanism which includes a gripper for seizing the leading end of a loop of tie wire as it is drawn taut around the package and while the knot is being formed.

Another object of the invention is to provide electrical control means whereby the various operations of the knotter mechanism are performed automatically in proper sequence.

These and other objects will become more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is an elevational view showing the general arrangement of the principal elements of an automatic wire-tying machine having the knotter mechanism of the invention incorporated therein;

FIGURE 2 is a front elevational view of the knotter of the invention;

FIGURE 3 is a plan view of the knotter;

FIGURE 4 is a sectional view taken on the plane of line IVIV of FIGURE 3;

FIGURE 5'is a sectional view taken along the line V-V of FIGURE 3;

FIGURE 6 is a sectional view taken along the line VIVI of FIGURE 5;

FIGURE 7 is a sectional view taken along the line VIIVII of FIGURE 6;

FIGURE 8 is a sectional view taken along the line VIIIVIII of FIGURE 6;

FIGURE 9 is a sectional view with parts broken away taken along the plane of line IXIX of FIGURE 2 showing elements of the knotter in position during the twisting cycle of the operation of the machine;

FIGURE 10 is a view similar to FIGURE 9 but showing the elements of the knotter in position during the wirefeed cycle;

FIGURE 11 is a sectional view taken along line XI- XI of FIGURE 5 showing elements of the knotter in position during the wire-feed cycle;

FIGURE 12 is a view similar to FIGURE 11 showing elements of the knotter in position during the twisting cycle;

FIGURE 13 is a sectional view taken along the line XIII-XIII of FIGUREIII;

FIGURE 14 is a partial sectional view taken along the line XIV-XIV of FIGURE 13;

FIGURE 15 is an elevational view taken along the line XVXV of FIGURE 14;

FIGURE 16 is a perspective view showing the gripper assembly of the knotter;

FIGURE 17 is a partial sectional view taken along the line XVIIXVII of FIGURE 3;

FIGURE 18 is a sectional view taken along the line XVIIIXVIII of FIGURE 17;

FIGURE 19 is a sectional view taken along the line XIX--XIX of FIGURE 17;

FIGURE 20 is a perspective view showing the gear and pinion assembly and its relation with the wire guiding and ejecting means;

FIGURE 21 is a perspective view of the wire cover which fits on the structure of FIGURE 20;

FIGURE 22 is a view with parts omitted taken along the line XXII-XXII of FIGURE 23 showing the vertical lever of the knotter;

FIGURE 23 is a sectional view taken along the line XXIIIXXIII of FIGURE 22 with some associated parts added;

FIGURE 24 is a perspective view showing what we designate as the load-and-fire actuator with associated parts;

FIGURE 25 is an end view of the guide track loadand-fire actuator with parts broken away;

FIGURE 26 is a side elevational view of the guide track load-and-fire actuator with parts broken away;

FIGURE 27 is a sectional view taken along the line XXVII-XXVII of FIGURE 5 showing the means for severing the tie wire from the supply coil; and

FIGURE 28 is a sectional view taken along the line XXVIIIXXVIII of FIGURE 27.

Referring more particularly to the drawings a main base 2 of an automatic wire-tying machine 3 has the knotter mechanism of the invention incorporated there n.

The base 2 is provided with a raised platform 4 at one end and an upstanding frame 6 adjacent the platform.

A wire feed mechanism 8 (more fully described and claimed in copending application Serial No. 19,737, filed April 4, 1960, of Linehan et a1.) is located on the platform 4 and the knotter mechanism indicated at 10 is or platform F extends through the guide track and has a slot 19 in line with the lower transom thereof. A brief description of the general operation of machine 3 is interposed at this point to aid in an understand ng of the detailed description of the knotter of the invention which follows.

Prior to initiation of a wire-tying cycle, the leading end of a tie wire W (FIGURE 1) is fed into the machine by the wire-feed mechanism 8 from a supply coil or other source (not shown). Any known feed mechanism may be employed such as that shown in Patent No. 2,912,099. As the wire is fed in, the leading end thereof is pushed from left to right, along the lower portion of the guide track 12, through the knotter mechanism 10, around the upper portion of the guide track, and then along the lower transom of the guide track and then through the knotter mechanism a second time. The leading end of the wire thereupon enters and is seized by a gripper element (to be described in more detail later) forming part of the knotter mechanism.

For the purposes of explanation, the leading end of the tie wire W which travels the full circuit of the guide track 12 and enters the knotter mechanism a second time will be designated W while the portion of the wire W which travels along the lower transom of the track and enters the knotter mechanism only once will be designated W The overlapping portions W and W of wire W are disposed in two separate grooves in the bottom portion of the guide track 12 and in the knotter mechanism 10 after being fed into the machine (FIGURES 10 and 11) which is then ready to be operated for applying the tie wire around a package P. Packages P are moved sequentially along the platform F through the window formed by the guide track 12, by means of roller conveyors (not shown) and are stopped one or more times therein for the application of a tie. As each package moves into tying position, the leading end of wire W is held by the gripper element in the knotter mech anism 10 and the wire-feed mechanism 8 is operated in reverse direction to pull the wire W and portion W thereof from right to left, as viewed in FIGURE 1. Upon retraction, the surplus wire is pushed into the escapement 16. As the wire is retracted, the loop thereof originally retained in the upper portion of the guide track 12 is pulled out therefrom and drawn taut around the package P. The knotter mechanism 10 is then actuated to cause a portion of the bottom of the guide track 12, which forms part of the knotter mechanism, to be lowered away from the overlapped wires W and W The twister pinion of the knotter mechanism is then moved into engagement with the overlapped wires and driven to twist them together and form a knot K on the bottom side of the package. A cutter (described later) is then operated to sever the tie from the wire source and wire for the next tie is fed into the track preparatory to a repetition of the strapping operation.

Of the parts of the machine thus far discussed, only the knotter mechanism 10 constitutes the present invention. The remaining parts are not claimed herein but have been shown and will be described hereinafter only to the extent necessary for a clear understanding of the knotter mechanism, the details of which will now be described. The knotter mechanism 10 consists essentially of a twister powered by a reversible hydraulic motor 22 through a power transmission 24 (FIGURES 1 and 2). For greater clarity and ease of understanding the following description and explanation are subdivided under the following headings: Twister, Power Transmission, and Operation.

Twister The twister 20 is mounted on a support plate 26 which extends at right angles to the front face of the machine 3 below the support frame 6 (FIGURES 1, 2, 3 and 4) and is secured to the base 2 by means of screws 28. A pair of spaced bosses 30 project upwardly from the end of the plate 26 below the frame 6 and in approximate vertical alignment with the guide track 12 (FIG- URE 4). A shaft 34 is journaled in the bosses 30 and pivotally supports a vertically extending lever 32. An arm 36 having a roller 38 journaled in the end thereof projects from the inner face of lever 32 and a pair of spaced fingers 49 and 42 project inwardly from the top thereof. The fingers 40 and 42 are attached to the lever by means of screws 40 and 42, respectively. Ears 43 and 45 (FIGURES 4 and 22) are spaced below the fingers 40 and 42, respectively, on lever 32. Pins 43' and 45' project laterally from the ears 43 and 45, respectively (FIGURES 2, 3, 4 and 5). Lever 32 extends upwardly in front of the frame 6 and terminates adjacent the outer side of the guide track 12, the fingers 40 and 42 extending toward the guide track.

A twister-gear housing 44 has a leg 46 depending angularly therefrom by Which it is pivotally mounted on the shaft 34. The housing 44 is normally positioned adjacent the side of the lower portion of guide track 12 opposite the lever 32 (FIGURES 3, 4, 5, 9 and 10). An ear 47 projects from the leg 46 and has a roller 49 journaled in the end thereof for a purpose which will shortly become apparent. The housing 44 contains in suitable recesses a twister gear 48, a twister pinion 52 and an intermediate gear meshing therewith. A detachably mounted cover plate 54 forms one side of the housing 44 and serves to retain the gears 48 and 50 and twister pinion 52 therein (FIGURES l7, l8 and 19). Pinion 52 is provided with a longitudinal slot 56 which extends inwardly from its periphery. A slot 58 extends across the face of the housing 44 and the edge of cover 54, in alignment with the slot 56, for a purpose which will become apparent (FIGURES 17 and 18).

The twister gear 48 is formed with a hub 60 which projects outwardly of the side of the housing 44 remote from the cover plate 54. The intermediate gear 50 has no journals but is rotatably confined in housing 44 (FIG- URES l7 and 19). The projecting hub 60 of the gear 48 is provided with a diametrically extending slot 62 in its outer face as well as a notch 64 in its periphery. A pawl 66 is pivoted to the housing 44 adjacent hub 60 and is pulled thereagainst by a tension spring 63. Pawl 66 limits the rotation of the hub 60 and gear 48 in counterclockwise direction, as viewed in FIGURE 17, and also serves to position the gear 48 after a twist has been made, as will be more fully explained later.

As best seen in FIGURES 9, 10 and 20, a vertically extending way 70 is formed on the face of the housing 44- by a slot in block 72 attached thereto by screws 74. A boss 76 projects outwardly and upwardly from block 72 (FIGURE 20) and has journaled therein a yokeshaped bell crank 78 one arm of which is a flat plate. The bifurcated arms 82 thereof carry adjustable stop screws 84 (FIGURE 21). A T-slide S6 reciprocable in way 79 has in its top two parallel grooves 88 and 90 adapted to form part of the guide track 12, as will be more fully explained hereinafter (FIGURES 10, 11 and 20).

The bottom of lever 32 projects below support plate 26 and is constantly urged outwardly by a spring-pressed push rod 92, pivotally connected to the lever and having thereon a coil compression spring 94. The inner end of the rod 92 fits slidably and loosely in a socket 96 of a lug 98 which depends from the underside of the support plate 26. The effect of spring 94 is to urge the upper portion of lever 32 towards the guide track 12 so that fingers 40 and 42 extend over the bottom portion thereof. A toggle linkage 100 has one end pivoted to the bottom of lever 32 adjacent the rod 92 and its other end to an ear 102 depending from the underside of support plate 26. An adjustable stop screw 104 (FIGURE 4) is threaded through support plate 26 and normally bears against the link 100. The purpose of the toggle linkage and stop screw 104 is to limit the angular movement of lever 32 (FIGURES 2, 3, 4, 5 and 23).

A rod 106 (FIGURE 4) has one end pivotally connected to the leg 46 of housing 44. The other end of the rod fits loosely in a hole in a boss 188 on plate 26. Rod 106 by virtue of a coil compression spring 110 thereon, constantly urges gear housing 44 toward the guide track 12. A toggle linkage 112 is connected by one end to the leg 46 at a point intermediate the rod 106 and the pivot shaft 34, and by the other end to an upstanding car 116 on plate 26. An adjustable stop screw 114 is threaded through the ear and bears against the linkage 112 to limit the pivotal movement of housing 44.

A block 118 (FIGURE 9) is mounted on frame 6 and projects outwardly therefrom through the lever 32. The block 118 carries a lever 120 pivoted thereon so that one end extends through a slot 122 at the lower end of T-slide 86 (FIGURES 9 and 10). Helical compression springs 12.6 seated in recesses in block 72 engage the head of T-slide 86 to constantly urge it upwardly (FIG- URE 20). A piston 124 is reciprocable in a bore cylinder in the block 118 and engages the outer end of the lever 1 20 to force the T-slide downwardly against the pressure of springs 126, as will be more fully explained later (FIGURES 9, 10, 13 and 20). A pair of spaced stop members 128 are carried by and project upwardly from the block 118 to limit the movement of gear housing 44 during certain stages in the operation of the knotter mechanism, as will be more fully explained, by engaging lugs 130 which project from opposite sides of the T-slide 86.

The gripper element mentioned above includes a housing 132 (FIGURES 13, 14 and 16) mounted on support 6 and projecting under the guide track 12 adjacent the end of groove 90, and under the finger 42 of lever 32. A continuation of the groove 88 extends through the housing 132 as at 134. The finger 42 serves as the fixed upper jaw of the gripper assembly. A lower jaw 136 is slidably mounted in the housing 132 for movement toward the finger 42 by a piston 138 slidable in a bore in the housing 132 and urged in releasing direction by a spring 140. A load-and-fire actuator 142 is mounted on gripper housing 132 for operating a switch 144 through an arm 146 pivotally mounted on frame 6 (FIGURE 15). The trigger of the actuator 142 is in the form of an L-shape pivotally mounted lug 148 which projects into a pocket 150 in the lower jaw 136 so as to be engageable by a wire-end entering therein.

A second load-and-fire actuator, designated generally by reference numeral 152 (FIGURES 24-26), is mounted on frame 6 adjacent the ear 43 of lever 32 for operating a switch 154 through a pivotally mounted arm 156. The trigger of the actuator 152 is in the form of a pivotal L- shape finger 15 8 which extends over the bottom portion of the guide track 12 so as to be engageable by a wire being stripped from the guide track, as will be more fully explained hereinafter.

Power Transmission The power transmission 24 includes a housing 168 (FIGURE 3) which is mounted on frame 6 by screws 162 and contains three sets of bearings 164, 166 and 168 (FIGURE 6) in vertically spaced relation. A coupling 172 connects motor 22 with a shaft which is journaled in bearings 164 and carries a sector gear 174 keyed thereon intermediate its ends. Rotation of the shaft 170 and the sector gear is limited by a pair of adjustable stops 176 and 176 (FIGURE 5) which are mounted on the base 2 on either side of the shaft 170 and are engageable by the sector gear 174. The stops 176 and 176' are pivotally mounted on brackets 178 and 178' respectively, and are adjustable to vary the limits of rotation of shaft 178 by means of a pair of screws 180 threaded into the base 2. A switch 182, is actuatable by 6 stop 176 on engagement therewith of the sector gear 174 when it reaches the right end of its path of travel and a switch 184, is similarly actuatable by the sector gear when it reaches the opposite end of its path of travel, through stop 176.

A shaft 186 is journaled in bearings 166 with one end 188 (FIGURE 6) projecting beyond the bearings. Three cams 190, 192 and 194 are spaced axially along the projecting end 188 which is journaled in a bearing 196 mounted on frame 6. A lever 189 (FIGURES 6 and 8) is pivotally mounted by one end on the housing 160 and is adapted to engage a notch formed in the periphery of shaft end 188. The lever is urged into engagement with the shaft by a tension spring 191 and thereby permits continuous rotation of shaft end 188 only in a clockwise direction as viewed in FIGURE 8.

A pinion 198 and a gear 200 integral therewith are rotatable on shaft 186. A pawl 282 (FIGURE 7) is pivotally mounted in a slot in the gear 200 and is constantly urged into engagement with a notch formed in the periphery of the shaft 186 by a spring-loaded pin 204. The pawl 282 is arranged to drive the shaft 186 only in the clockwise direction as viewed in FIGURE 7 upon rotation of gear 206 in the clockwise direction as will be more fully described.

Gear 198 meshes with sector gear 174. Gear 200 meshes with a gear 206 rotatable on a shaft 208 (FIG- URES 5-7). Shaft 208 is journaled in the bearings 168. A pawl 210 is pivotally mounted in a slot in the gear 206 and is constantly urged into engagement with a notch formed in the shaft 208 by a spring-loaded pin 212. The pawl 210 is arranged to drive the shaft 268 only in the clockwise direction (FIGURE 7). 208 projects beyond the bearings 168 and has a key 214 formed on the projecting end. The key 214 is adapted to fit in the slot 62 in the hub 60 of the twister gear 48 to provide a slidable driving connection between the shaft 208 and the gear 48.

A cutter assembly FIGURES 27 and 28) is provided in the bottom portion of the guide track 12 to the left of the finger 40, as viewed in FIGURE 3. The cutter assembly includes a grooved cutter bar 216 (FIGURES 5, 24, 25, 27 and 28) pivotally mounted by one end in and forming a removable portion of the guide track 12. The cutter bar 216 is urged constantly into a position aligning with guide track 12 by a tension spring 218. A thrust rod 220 is slidable in a bore in frame 6 to move the bar 216 upwardly at its free end to cut wire W at the proper time in the knotting operation, as will be more fully explained hereinafter. A lever 222 is pivotally mounted by one end on a boss 160' on the housing 160 subjacent the rod 220. A cam roller 224 is journaled in the lever 222' intermediate its ends for cooperation with the cam mounted on the projecting shaft end 188 (FIG- URE 6).

Cam 192 is arranged to cooperate with the cam roller 38 journaled in the end of the arm 36 (FIGURE 23), and cam 194 cooperates with the cam roller 49 journaled in the car 47 (FIGURE 4).

Operation As stated above, prior to an operation of the knotter of the invention, wire W has been fed into the machine and pushed around guide track 12 by wire-feed mechanism 8'. The leading end of the wire W is thereby inserted in the pocket 150 (FIGURES 1113, 15 and 16) of the gripper housing 132 and gripped between jaw 136 and finger 42, in a manner to be explained shortly. When a package P has been moved part way through the guide track 12, on platform F, a tying cycle may be initiated by operation of any convenient switch.

As the first step in the wire-tying operation, the wirefeed mechanism 8 is operated in the reverse direction so as to retract the wire W, strip it from the guide track 12 and draw it tightly around the package P. As the One end of shaft wire is stripped from the guide track and is pushed into the escapement 16, it actuates switch 154 through the actuator 152 (FIGURES 2 and 24-26). Switch 154 opcrates an electromagnetic valve which causes actuation of piston 124 and moves it upwardly to pivot arm 120 which, in turn, moves the T-slide 86 downwardly (FIG- URES 9 and 10). As the T-slide moves downwardly, the grooves 88 and 90 are lowered from the tensioned wires W and W and the lugs 130 are lowered from engagement with the stop members 128 (FIGURES 9, l and 20). Disengagement of the lugs 138 and stop members 128 permits the twister gear housing 44 to pivot on the pin 34 and move toward the tensioned wires under the force of spring 110 (FIGURE 4). The toggle linkage 112 and the stop 114 prevent the housing 44 from moving beyond wireengaging position.

As the housing 44 moves into wire-engaging position, the twister pinion 52 journaled in the housing engages the tensioned wires in its slot 56 and the leg 46 operates a switch 226 mounted on the frame 6. Operation of the switch 226 starts the motor 22 to rotate shaft 170 and sector gear 174 in clockwise direction as viewed in FIG- DRE 5. Clockwise rotation of the sector gear causes rotation of gear 198 in the counterclockwise direction. Gear 200 rotates with gear 198 (FIGURE 6) thus causes gear 206 to rotate in clockwise direction. Rotation of gear 296 in clockwise direction causes the pawl 210 (FIGURE 7) to engage the peripheral notch in the shaft 208 and rotate the latter in clockwise direction.

During the counterclockwise rotation of gear 200 the pawl 202 and the gear 200 exert a frictional drag on the shaft 186 which has a tendency to rotate the shaft. However, lever 189 (FIGURE 8) engages the peripheral notch on the end 188 of shaft 186 and prevents it from rotating in counterclockwise direction. Rotation of shaft 208 is imparted to the twister gear 48 through the driving coupling formed by engagement of the key 214 in the slot 62 of the hub of the gear 48. This engagement is effected in a manner which will be made clear later. The sector gear 174, gears 198, 200 and 206 are so dimensioned as to bring about a complete revolution plus a small fraction of a revolution of the shaft 208 upon movement of the sector gear from one stop 176 to the other stop 176' (FIGURE The twister gear 48 rotates through the same cycle as the shaft 208.

Rotation of the twister gear 48 drives the twister pinion 52 through the intermediate gear 50 to twist the lapped wires W and W to form the knot K (FIGURES 9 and 12). Gear 48 and pinion 52 are so dimensioned as to cause pinion 52 to rotate a predetermined number of complete revolutions plus a fraction of a revolution upon the one-plus revolution of the gear 48. The number of twists desired in the complete knot to be formed determines the number of revolutions of the pinion 52. The relative dimensions of the gears involved may be. varied to obtain the number of twists desired.

When the sector gear 174 reaches the end of its path of travel and contacts the stop 176, it operates switch 182 which reverses motor 22. Also, when the switch 182 is actuated it operates an electromagnetic valve controlling piston 138, to cause the gripper 136 to be released by spring 140. Switch 182 also operates a valve to permit retraction of piston 124. This permits springs 126 to raise the T-slide 86 as permitted by engagement of lugs 1 30 with the undersurfaces of stops 128. Reverse operation of motor 22 also causes rotation of shaft 170 in counterclockwise direction as viewed in FIGURE 5. As the shaft 170 rotates in counterclockwise direction, the sector gear 174 moves to the left until it reaches stop 176. This movement of the sector gear causes gears 198 and 200 to rotate in clockwise direction and gear 206 to rotate in counterclockwise direction, as viewed in FIG- URES 5 and 7.

As the gear 200 thus rotates in clockwise direction, the pawl 202 engages the peripheral notch in the shaft 186 and rotates the latter in clockwise direction as viewed in FIGURE 7. The cam shaft 186 which was idle on forward movement of sector gear 174 is then driven on the return swing of the sector gear. At the same time, the pawl 210 in gear 206 rides along the periphery of shaft 208 so that the shaft and gear 48 are not driven, permitting the twister pinion to remain stationary. However, the pawl 66 under the force of spring 68 serves to position the hub 60 by engagement with the notch 64 causing gear 48 to revolve slightly in counterclockwise direction as viewed in FIGURE 17. This partial rotation of gear 48 brought about by the pawl 66 causes the twister pinion 52 to assume a position where the side opening of slot 56 is in alignment with the slot 58 in the face of the housing 44 so that the pinion can be withdrawn from the completed knot. The positioning of gear 48 by pawl 66 also lines up slot 62 with key 214, permitting sliding disengagement of the driving connection.

Rotation of cam shaft 186 in clockwise direction turns cams 190, 192 and 194. Rotation of cam 190 effects tilting of lever 222 (FIGURES 27 and 28) to shift rod 220 and lift the right end of bar 216 out of alignment with the guide track 12. As the bar 216 thus moves out of alignment it cooperates with finger 40 to sever the wire W leading back to the wire-feed mechanism 8 so that the completed wire tie and knot K are freed from the supply wire.

Upon clockwise rotation, cam 194 engages the cam roller 49 and pivots leg 46 and housing 44 about pivot pin 34 to retract the pinion 52 from the completed knot K (FIGURE 10). As the housing 44 moves away from the completed knot, the T-slide 86 moves upwardly under the urging of springs 126 and raises the grooves 88 and 90 back into alignment with the guide track 12. As the T-slide moves upwardly it pivots the crank arm 78 back into track covering position (FIGURE 10). The pivotal movement of the crank arm is limited by the screws 84 contacting the cover block 72. The T-slide 86 does not complete its upward movement until the lugs clear stop members 128 as the housing is pivoted to its extreme retracted position as shown in FIGURE 10. As the T-slide moves upwardly it also causes the arm 120 to pivot and move the piston 124 into retracted position.

During its clockwise rotation cam 192 engages the cam roller 38 on arm 36 to pivot lever 32 about pivot pin 34 away from the housing 44. As the lever 32 thus pivots, the spring 94 is compressed (FIGURE 4) and the fingers 4t and 42 move clear of the guide track 12 to allow the completed knot K to be released toward the package P. When the cam 192 disengages from the cam roller 38, the spring 94 pivots the lever 32 back toward the guide track 12 to position fingers 40 and 42 thereover in proper position for the feeding of wire through the guide track preparatory to a subsequent strapping or wire-tying operation.

The cams 190, 192 and 194 must obviously be so related angularly on the projecting shaft end 188, or timed as to bring about the above described camcontrolled actions in the proper sequence, thereby causing each step of the knotting cycle to take place at the proper instant.

When the sector gear 174 reaches the left end of its path of travel, as viewed in FIGURE 5, it contacts stop 176 and actuate-s switch 184. Actuation of the switch 184 stops motor 22 and causes operation of the wire-feed mechanism 8 to feed wire around the guide track 12 preparatory to a subsequent strapping cycle. When the wire is thus fed around the guide track its leading end enters pocket and actuates switch 144 through actuator 142. Switch 144 stops the wire-feed mechanism and causes operation of an electromagnetic valve admitting fluid pressure behind piston 138 so that the wire end is clamped against finger 42 in the gripper assembly by jaw 136.

While one embodiment of our invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

We claim:

1. A knotter mechanism for wire-tying machines of the type having a platform adapted to support an article to be tied, and a guide track extending around the platform with a lower transom just below the platform, said platform having a slot therethrough in line with said lower transom in which said knotter mechanism comprises a slotted twister pinion, means mounting said pinion for movement between a first position in which said pinion is in line with said transom and a second position offset laterally therefrom, a movable grooved member disposed in said lower transom and adapted to replace said pinion, means effective to move said member downwardly from a position in line with said transom to make way for said pinion as it is moved into said first position, and means effective to move said member upwardly in line with said transom to replace said pinion when the pinion is moved to its said second position.

2. Apparatus as defined by claim 1 characterized by said member being slidably mounted on said knotter mechanism.

3. Apparatus as defined by claim 1 including spring means constantly urging said member upwardly.

4. Apparatus as defined by claim 1 including a cover plate pivoted on said knotter mechanism and extending over said member.

5. Apparatus as defined by claim 1 including fixed stop means engageable by a portion of said member until downward movement thereof causes said last mentioned portion to clear the stop means.

6. Apparatus as defined by claim 1 including a frame below said platform, and said means effective to move said member downwardly including power means mounted on said frame.

7. Apparatus as defined by claim 1 including a cutter bar pivotally disposed in said lower transom, said cutter bar having a longitudinal groove with one end adjacent said pinion when said pinion is in said first position, said bar being pivoted about its other end for uptilting movement, and a movable finger overlying said transom adjacent said one end whereby a wire in said groove is sheared between said finger and said cutter on uptilting of the bar.

8. Apparatus as defined by claim 7 including a frame below said platform, a cam shaft journaled therein, and means actuated by a cam on said shaft causing uptilting of said bar.

9. Apparatus as defined by claim 7 including a frame below said platform, a vertically extending lever pivoted on said frame, said finger being mounted on the upper end of said lever, and power means for tilting said lever to retract said finger.

10. Apparatus as defined by claim 9 including means for limiting the tilting movement of said lever.

11. Apparatus as defined by claim 9 characterized by a cam shaft journaled in said frame, and said power means including said last mentioned cam shaft and a cam thereon engaging said lever.

12. Apparatus as defined by claim 1 including a frame below said platform, a vertically extending lever pivoted on said frame and having a finger on its upper end overlying said transom, and a gripper jaw movable in said frame adapted to grip one end of a wire tie against said finger.

13. Apparatus as defined by claim 12 including power means for actuating said movable jaw.

14. Apparatus as defined by claim 12 including a cam shaft journaled in said frame, and a cam on said shaft effective to pivot said lever and retract said finger.

References Cited in the file of this patent UNITED STATES PATENTS 717,551 Depew Jan. 6, 1903 1,009,006 Young Nov. 14, 191-1 1,867,128 Wunderlich July 12, 1932 2,129,845 King et al Sept. 13, 1938 2,654,403 Roe Oct. 6, 1953 2,922,359 Brouse et al. J an. 26, 1960

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