US3179038A - Wire tying machine - Google Patents

Description

April 20, 1965 INVENTOR THOMAS B. MACKENZIE ATTORNEYS April 20, 1965 T. B. M KE NZIE WIRE TYING MACHINE A TTORNEYS 5 Sheets-Sheet 2 INVENTOR THOMAS B. MACKENZIE jmvx 3'79" mm mm mmkm mm m VN\ Filed Nov. 20, 1962 T. B. M KENZIE WIRE TYING MACHINE April 20, 1965 5 Sheets-Sheet 3 Filed NOV. 20, 1962 m GI INVENTOR THOMAS B. MACKENZIE ATTORNEYS A ril 20, 1965 T. B. M KENzlE WIRE TYING MACHINE Filed NOV. 20, 1962 5 Sheets-Sheet 5 ATTORNEYS.

United States Patent 3,179,038 WIRE TYING MACHINE Thomas B. MacKenzie, Hamilton, Ontario, Canada, assignor to Gerrard Company Ltd, Hamilton, Ontario, Canada Filed Nov. 20, 1962, Ser. No. 238,948 6 Claims. (Cl. 100-26) This invention relates to automatic Wire tying machines of the type in which a length of wire from a supply is looped around a bale or bundle, then drawn tightly onto the bundle, a knot is formed where the loop closes and finally the loop is severed from the wire supply.

There are several automatic wire tying machines of the above type in use at the present time but they are of complex structure with many moving parts and this, of course, is undesirable, if it can possibly be avoided without sacrificing efficiency, since a greater number of moving parts invariably means a greater chance of frequent breakdown with consequent loss of working time and greater maintenance costs.

It is accordingly a primary object of the present invention to provide an automatic Wire tying machine of simplified construction, less liable to breakdown and easier to maintain than hitherto known machines of this type.

An important feature of the invention is the knotter mechanism, which comprises a vertically reciprocable wire lifting device, a horizontally reciprocable wire holding device adapted to hold the overlapping portions of the wire loop releasably, the wire holding device being mounted within the wire lifting device, and a twister unit reciprocable to lift the lifting device, displace the holding device, pick up the overlapping wire portions in a wire twister pinion, twist said overlapping portions together to form a knot and retract to release the knot and allow the wire holding and lifting devices to return to their initial positions. The twister unit can also serve to grip the free end of the wire against a suitable abutment, which may be provided on the wire lifting device, thus eliminating the need for separate gripping mechanism. Preferably also, the twister unit bends the free end of the wire over the wire portion which it overlaps so that the free end will be tucked tightly against the underside of the tied bundle when the knot is released from the twister unit.

Another important feature of the invention is the wire drive mechanism, which comprises a first constantly driven separable pair of rollers for feeding the wire in and a second constantly driven separable pair of rollers for initially withdrawing the wire to start the tightening of the loop onto the bundle, this in contradistinction to hitherto known machines which used only one pair of rollers driven first in one direction to feed the wire in, then stopped and driven in the opposite direction for initial withdrawal of the wire. A final tensioning device is provided to take over and complete the tightening of the wire loop onto the bundle and, in a preferred embodiment of the invention, this final tensioning device is brought into action when a guide arm, which forms the entry portion of a loop-forming frame and is pivotally mounted at its exit end, is raised to contact an electrical switch by the initial tension placed on the wire in the arm by said second pair of rollers.

A specific and presently preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of a wire tying machine;

FIGURE 2 is a sectional plan view taken on the line II-II of FIGURE 1;

FIGURE 3 is a sectional front elevation of the machine;

FIGURE 4 is a sectional side view of the wire holding device;

ICC

FIGURE 5 is a plan view of the final tensioning device gripper;

FIGURE 6 is a sectional side elevation taken on the line VIVI of FIGURE 2 and showing the wire lifting and holding devices in their normal position and the twister unit retracted;

FIGURE 7 is a view similar to FIGURE 6 but showing the twister unit advanced, the wire lifting device raised and the wire holding device pushed back from its normal position;

FIGURE 8 is a view showing the drive to the wire feed and tensioning rollers;

FIGURE 9 is a detail view showing the means for gripping and tucking the free end of the wire;

FIGURE 10 is a side elevation of the gear train for driving the wire feeding and initial loop tensioning device.

The machine illustrated has a wire feed and initial retraction unit 23, a loop-forming track 24 in a frame 25, a final tensioning or retraction unit 22, and knotter mechanism comprising a wire lifting device 26 and a twister unit 27, the Whole being mounted on a base 20 having legs 21. A bundle to be tied is carried to a position within the frame 2-5 by conveyor rolls 28, 29 on either side of and fore and aft of the knotter mechanism 26, 27, respectively.

A more detailed description follows. The free end of the binding wire from a supply reel, not shown, is threaded through a bell-mouth guide 30 which is mounted at the top of the left hand wall 31 of a base member 32. The wire passes through the final tensioning means which includes a gripper member 33 secured upon the upper surface of a reciprocating carriage 34. The gripper member comprises a base 35 (see FIGURE 5) upon which is super-imposed an anvil 36 and a spacer plate 37 which also acts as a limiting stop for a dog 38. The dog 38 is provided with a bore adapted to receive a pivot screw 39 threadedly engaged in base 35. The dog is provided with wire contacting face 49 and an abutment surface 41 which cooperates with a stud 42. The stud is threadedly mounted in a block 43 secured to surface 44 of base 32. The dog 38 is also provided with a tail portion 45 that contacts wall 46 of spacer plate 37 to limit opening movement of the dog. The dog is biased to a closed, wire gripping position by a compression spring 47 which seats in blind bores 48 and 49 in the dog and in plate 37, respectively. In the wire feeding position, when the carriage 33 is in the position shown in FIGURE 5, the stud 42 maintains the dog 38 in an open position against the action of spring 47 and the friction of the wire. The stud also serves to force the dog away from the wire after it has been operated in a tensioning cycle and has become to some extent wedged against the wire under the tensioning strain. Intermediate the spacer plate 37 and anvil 36 there is formed a slot 50 to permit free passage of the wire and also to direct the wire between the dog 38 and anvil 36. The gripper member is provided with a cover plate 51 which maintains the wire within the slot and precludes the entry of foreign matter therein.

Theend of the wire passed through the slot 50 goes through an aligned bore formed in a guide block 52 fixed on the upper surface 44 of base 32. The bored block 52 maintains the wire intermediate the final tensioning means 22 and the feed and initial tensioning means 23 free of kinks and also ensures the proper alignment of the wire. The wire now enters a slot 53 (FIGURE 3) formed in a wire guide 54 that is secured to a bracket 55. The bracket 55 is mounted upon the frame 25 of loop-forming track 24. The wire now enters between wire tensioning or feed- out rollers 56 and 56 of feed and initial tensioning device 23 which consists of upper and lower assemblies 57 and 58, respectively. The assemblies 57, 58 are substantially identical in construction.

The upper assembly 57 comprises spaced bearing plates 59 and 60 (FIGURE '2) between which is rotatably mounted a shaft 61. The shaft d1 protrudes through bearing plate 59 and terminates in a bearing secured to bracket 55. The opposite end of the shaft protrudes through a bearing mounted upon hearing plate 6t and a bearing secured to bracket55'. Between bearing plates 59 .and 60, tensioning roll 56 is keyed to shaft 61 in driving relation. The end of shaft 61 protruding through bracket 55' is provided with a sprocket 62 (see FIGURE 8) the function of which will be more fully explained below. Keyedito shaft 61, intermediate bearing plate 6% and bracket 55, is a spur gear 67 (see FIGURE The spur gear meshes with and drives idler spur gears 68 and 69. The spur gear 6? coacts with a spur gear 74) which is keyed to a shaft 71. The shaft 71 extends between and is rotatably mounted in bearings secured to bearing plates 59 and (it) respectively. The portion of shaft 71 intermediate bearing plates 5% and 60 has keyed thereto a wire feed roller 72. upon it a lug 73 (FIGURE 3) which is provided with a bore. Attached to lug 73 by pin 74 and clevis 75 is piston rod 76 of fluid motor 77.

The lower assembly 53 of wire feeding and tensioning member 23 is identical to assembly 57 but is mounted in a converse manner to assembly 57. The shaft 61, upon which the bearing plates 59 and 60' are journalled, is rotatably mounted in bearings secured to brackets 55 and 55' respectively. The shaft 61 protrudes through the bearing mounted upon bracket 55' and has mounted upon it, in driving relation, a sprocket 78. The sprocket 78 is driven from sprocket 62 by sprocket chain 63 whilst another sprocket 7% on shaft 61 is driven by motor 80 through reduction gearing 31 and sprocket chain 82.

Shaft 61' has keyed thereto a wire feed roller 72, rollers 72 and 72' grasping the wire between them when in operative position as will hereinafter be more fully described. Shaft 71' is mounted for rotation, in a similar manner to shaft 71, in suitable bearings secured to hearing plates 59' and 6t). Secured by a key to shaft '71, intermediate bearing plates 58' and 60', is tensioning roller 56'. The shaft 71' and its associated tensioning roller 56 are rotated by spur gear 70' which is driven by idler gears 68' and 69. The idler gear 68' is driven by spur gear 67 keyed to shaft 61'. The bearing plate 59' has formed thereon lug 73' which is provided with a bore. A clevis 84 attached to piston rod 85 of fluid motor 86 is secured to lug 73 by a pin 83.

The assembly 53 is also provided with a wire guiding member 87. The wire guiding member is secured to bearing plate 60 intermediate the rollers 56' and 72. The wire guiding member has formed therein a groove 88 the longitudinal centre line of which coincides with the longitudinal centre line of the wire and also the circumferential centre of the grooves formed in the wire feeding and tensioning rollers. The wire guiding member 87 as shown in FIGURE 3 is of truncated diamond shape. The triangular shaped portion within which the groove is formed projects upwardly between the rollers 55 and 72 to ensure, when the assemblies 57 and 53 are manipulated, that the wire is maintained in centered'position.

The wire emerging from between the Wire feeding and tensioning rollers enters bell mouth 89 and passes through conduit 92 of arm 99 that is pivoted at 91 on wire iifting device 26. From conduit 92 the wire enters channel 93 (FIGURE 4) of wire holding device 94 adapted to be horizontally reciprocated within wire-lifting device 26. From the exit end of channel 93 the wire enters channel 95 (FIGURE 3) formed in loop-forming track 24-. The track, of the type shown in United States Patent 2,908,215 and also shown in FIGURE 1, is mounted within an inverted U-shaped frame which positions the loop forming track substantially on the longitudinal centre line of base 20. The channel Q5 of loop forming track 24 is formed in the shape of a right hand helix. The wire The bearing plate 59 has formed emerging from channel @6 (FIGURE 2) of loop forming track 24 enters channel 97 of wire holding device 9 V The end of the wire emerging from the exit end of channel'97 strikes a switch 93, actuation of which ener gizes fluid motors 77 and 1%. Motor 77 separates wire feed rollers 72 and 72' to stop the wire feed. The motor Hit) forces wire twisting head 27 in towards wire lifting device 25. Cam track 1E1 (FIGURE 6) rigidly mounted on wire twisting head 27 contacts rollers I612. The rollers 1492 are secured to slide 103 of wire lifting device 26. V

The wire-lifting device comprises upright ways Hi4 (FIG- URE 2) which are secured upon base 26 in predetermined spaced relation. The slide 193 is of inverted U shape and reciprocates in a vertical direction in ways 1%. A transverse bar 1% is secured between the arms of the slide adjacent their top-most edges immediately be low the cover res. Slidably mounted in hushed bores formed in bar 195 are carriage shafts 107. The shafts 107 are joined at their outer ends by a cross-piece Hi7 which is urged toward bar M5 by a spring 197" secured at one end to the cross-piece and at its other end to the bar. The inner ends of the shafts 167 are secured to head member 1438 (see FIGURE 4) which is provided with an upper leaf member 109. The leaf member 199 is rockably secured to head 10% by a bolt 11% and a boltencircling compression spring Iii. The Wire receiving channels 93 and 97, hereinbefore mentioned, are formed in leaf 109. As the wire twisting head 27 advances and forces the wire holding device E4 fully back the portions of the wire housed in channels $3 and 97 spring out of the channels and through wire receiving recess 112 into slot 113 of wire twisting pinion 114. The free end of the wire is gripped between the twister head 27 and an abutment 115 which is described hereinafter in detail in connection with FIGURE 9. When the twister head moves it strikes a switch 13.6 which energizes fluid motor 86 to bring together the initial tension rolls 5'6 and 5'6 whenever another switch 116a, which projects above the conveyor rolls 28, 29 is actuated by a bundle fed by the conveyor rolls into position to be tied. Actuation of switch 115a stops the conveyor rolls 28, 29 as well as completing the circuit to switch 116. The rollers 56 and 56' pull the wire back, stripping it from the loop forming track and tensioning it about the bundle to be tied.

The upward movement of the wire lifting device elevates the pivot point 91 of swinging arm 9t? and as the wire tensioning rolls 56 and 56' pull the wire taut the free end of arm 96 is raised by the wire and strikes a switch 117 to energize fluid motors $6 and 119 (FIGURE 3). Motor 36 separates rollers 55 and 56' so that they stop pulling the wire. Attached to piston rod 120 of motor 119 is the final tensioning carriage 34. The movement of the carriage away from stud 4-2 permits wire gripping member 33 to grasp the Wire and exert a pull thereon and tension the wire to a predetermined tautness. When piston 120 has reached the end of its stroke a switch 121. (FIGURE 2) is tripped by a cam 122 on a shaft 123 which has one end secured to the carriage 34 and its free end slidably mounted in a fixed bracket 124. The trip ping of switch 121 energizes fluid motor 125 (FIGURES 6 and 7) which actuates piston rod 126 and rack I27 attached thereto to travel in the direction of arrow 128. The rack 127 is in mesh with and rotates spur gear 129. Rotation of spur gear 129 (see FIGURE 7) imparts rotation to spur gear 130, spur gear 131 and twister pinion 114 which unites the ends of the wire by a twisted joint or knot. In a well-known manner the wire about the bundle is severed from the wire in conduit 92 by cutter 132 which is actuated by cam 133 attached to shaft 134 of spur gear 131.

As rack 127 completes its stroke it strikes switch 135 (FIGURE 2) which closes a circuit to energize fluid motor 1% to retract the twister unit 27, thus allowing the knot to escape from the twister pinion T1 5 and spring up against the underside of the bundle being tied. Wire lifting dea vice 26 returns to its normal position by gravity and wire holding device 94 is returned to its normal position by spring 107".

As twister unit 27 retracts it actuates switch 136 to start the drive to conveyor rolls 28, 29 and to energize fluid motors 119, 77 and 125 which, respectively, return final tensioning unit 22 to its initial position, bring wire feedin rollers 72, 72 together and return rack 127 to its initial position. The feed-in rollers, of course, feed the wire around the loop-forming track 24 until the free end strikes switch 98 whereupon the feed-in rollers are separated and the wire twister unit moves in to grip the free end of the wire, pick up the wire portions to be knotted and actuate switch 116 so that the machine is now ready to work on the next bundle as soon as it trips switch 116a. As before, when switch 116a is tripped, the conveyor rolls 28, 29 are stopped and tensioning rollers 56, 56' are brought together to start pulling the wire back out of track 24. This continues until arm 90 trips switch 117 to separate the tensioning rollers and bring the final tensioning means into operation. The latter, in turn, trips switch 121 to advance the rack 127 and tie the knot. The advancing rack trips switch 135 again to retract twister unit 27 and finally unit 27 trips switch 136 to ready the machine for another bundle. It can be seen, therefore, that the machine is fully automatic and will continuously repeat the above sequence of operations, once initiated, until the feed of bundles to the machine is stopped or until the machine is switched off.

An appealing feature of the machine according to the invention is its slim design, which enables two machines to be placed side by side so that two straps can be applied to a bundle simultaneously.

Another appealing feature of the machine is that it can tie a strap around a bundle in approximately 7 seconds.

As stated above, the need for separate gripping mechanism, to grip the free end of the wire in the machine and hold same while the wire is being tensioned, is eliminated in the machine according to the invention. Thus, the twister unit 27 and abutment 115 co-operate to grip the free end of the wire. As shown in FIGURES 6 and 9, the abutment 115 is formed by an upright finger 137 pivotally mounted intermediate its ends on wire lifting device 26. That portion of the wire parallel to the free end lies in a slotted guide 138 also mounted on the wire lifting device withits slot 139 opening towards and adapted to be closed by the finger 137, the latter being urged into slot-closing position by spring 140. The wire is held in the slot 139 until, after final tensioning of the wire, the device 26 is lowered again and the tension in the wire causes it to strip from the slot and snap against the underside of the tied bundle, pushing the finger away from the end of the slot in so doing. The finger, of course, is returned to slot-closing position by spring 140 as soon as the wire has escaped. The Wire is free to move laterally and longitudinally in slot 139 so that it is not gripped by the finger 137. Thus, when tension is placed on the wire it can be pulled freely through the slot. However, the free end of the wire is gripped between the surface 141 of the finger and the recessed surface 142 (FIGURE 9) of the twister unit 27.

Another attractive feature of the invention is the tucking in of the free end of the wire against the tied bundle. This is achieved by a projection 143 on the twister unit adjacent said recessed surface 142. As the twister unit moves in, the projection 143 engages the free end of the wire and bends it around finger 137 to lie over the wire portion on the exit side of slot 139. Thus, when the wire springs up against the underside of the bundle, the free end will be tucked securely against the bundle by the Wire portion which it overlaps.

What I claim as my invention is:

1. An automatic wire-tying machine comprising vertical wire-loop-forming track means having two track sections at the bottom thereof in side-by-side relationship,

one being an entry section and the other an exit section, displaceable wire-holding means having openable wireholding passages therein normally in alignment with said two track sections at the exit ends of said sections, wire feed means for feeding wire through said track means and said holding means, a horizontally reciprocable wire-twisting unit, means for moving said wire-twisting unit in to displace said wire-holding means and pick up wire portions held thereby, initial tensioning means for placing initial tension on the wire in said track means, final tensioning means operable subsequent to said initial tensioning means for placing a final tension on the wire, a twister pinion in said wire-twisting unit, means for driving said twister pinion to twist said wire portions together and form a tied loop, means for cutting the formed loop from the wire remaining in the entry section of said track means,

means for returning said wire-twisting unit and said wireholding means to their original positions after the wire twisting operation, conveyor means for conveying a bundle into position to be tied, drive means for driving said conveyor means, a first switch located in the path of the free end of the wire as it leaves said wire holding means for the second time and adapted, when actuated by the free end of the wire, to cause inward movement of the wire twister unit and to render ineffective the wire feed means, a second switch actuable by the Wire twisting unit as it moves in, a third switch in series with said second switch and actuable by a bundle conveyed into position to be tied, actuation of said second and third switches causing said initial tensioning means to be brought into operation and interruption of the drive to said conveyor means, a fourth switch actuable by the entry section of said track means swinging upward about its exit end in response to the initial 1 tensioning of the wire and, when actuated, causing said final tensioning means to be brought into operation and rendering ineffective said initial tensioning means, a fifth switch actuable by said final tensioning means for causing said means for driving the twister pinion to be brought into operation, a sixth switch actuable by said means for driving the twister pinion and adapted, when actuated, to cause return of said wire twisting unit to its initial position, and a seventh switch actuable by said twisting unit when returned to its initial position to cause the wire feed means to be brought into operation again, re-establish the drive to the conveyor means, and re-set the final tensioning means and the means for driving the twister pinion.

2. An automatic Wire tying machine as claimed in claim 1, including a projection on said wire twisting unit, which projection engages the free end of a wire in the machine as the wire twisting unit is moved in and bends said free end over a parallel wire portion so that the free end will be tucked against the underside of a tied bundle.

3. An automatic wire tying machine comprising vertical wire-loop-forming track means having two track sections at the bottom thereof in side-by-side relationship, a wire lifting device, a wire holding device slidably mounted horizontally in said wire lifting device and having two normally closed but openable wire guide passages therein in side-by-side relationship, resilient means urging said wire holding device into a normal position wherein said passages are aligned with said two track sections, a wire twister unit, means for advancing said wire twister unit from an inoperative position to an operative position in which it displaces said wire holder device and for returning it to said inoperative position, interengageable means on said wire lifting device and said wire twister unit to raise said wire lifting device in response to advancing movement of said wire twister unit, a slotted wire twister pinion in said wire twister unit, a face on said Wire twister unit for contacting said wire holding device, the wire twister unit having a recess extending from said face to allow the wire portions that are to be twisted to pass into the slot in the wire twister pinion, the passages in said Wire holder device when the latter is raised as aforesaid being on a level with said recess.

4. An automatic wire tying machine as claimed in claim 3 wherein an abutment is provided to cc-operate with the wire twister unit to clamp the free end of a loop of wire in the machine.

, 5. An automatic wire tying machine as claimed inclaim V 3, wherein the wire twister unit has a projection which,

as the twister unit advances, engages the free end of the loop of wire and bends it over the wire portion which it overlaps so that the free end will be tucked against the underside of a tied bundle. i

I 6. An automatic wiretying machine comprising vertical wire-loop-forming track means having two track sections at the bottornrthereof in side-by-side relationship, one of said sections being an entry section and the other being an exitsection, a first pair of rollers for feeding wire into,

around and out of said track means,'means for separating and bringing'together the rollers of said first pair, a second pair of rollers for initial pulling of wire from said track means, means for separating and bringing together the rollers of said second pair, drive means driving at least one roller of each said pair constantly when the machine is in operation, final tensioning means adapted to act, as the rollers of said second pair are separated, to exert a final pull on the wire-and tighten same around a bundle being tied in the machine, said entry section being pivotally mounted at its exit end on a horizontal pivot and a switch being provided above the entry end of said entry section. V

Reierences Cited by the Examiner UNITED STATES PATENTS 1/56 'Cheeseman. 3,057,289 10/62 Luthi 10,o 26 3,060,841 10/62 Van DeBilt -100 31 WALTER A. SCHEEL, Primary Examiner.

Claims (1)

1. 3. AN AUTOMATIC WIRE TYING MACHINE COMPRISING VERTICAL WIRE-LOOP-FORMING TRACK MEANS HAVING TWO TRACK SECTIONS AT THE BOTTOM THEREOF IN SIDE-BY-SIDE RELATIONSHIP, A WIRE LIFTING DEVICE, A WIRE HOLDING DEVICE SLIDABLY MOUNTED HORIZONTALLY IN SAID WIRE LIFING DEVICE AND HAVING TWO NORMALLY CLOSED BUT OPENABLE WIRE GUIDE PASSAGES THEREIN IN SAID-BY-SIDE RELATIONSHIP, RESILIENT MEANS URGING SAID WIRE HOLDING DEVICE INTO A NORMAL POSITION WHEREIN SAID PASSAGES ARE ALIGNED WITH SAID TWO TRACK SECTIONS, A WIRE TWISTER UNIT, MEANS FOR ADVANCING SAID WIRE TWISTER UNIT FROM AN INOPERATIVE POSITION TO AN OPERATIVE POSITION IN WHICH IT DISPLACES SAID WIRE HOLDER DEVICE AND FOR RETURNING IT TO SAID INOPERATIVE POSITION, INTERENGAGEABLE MEANS ON SAID WIRE LIFTING DEVICE AND SAID WIRE TWISTER UNIT TO RAISE SAID WIRE LIFTING DEVICE IN RESPONSE TO ADVANCING MOVEMENT OF SAID WIRE TWISTER UNIT, A SLOTTED WIRE TWISTER PINION IN SAID WIRE TWISTER UNIT, A FACE ON SAID WIRE TWISTER UNIT FOR CONTACTING SAID WIRE HOLDING DEVICE, THE WIRE TWISTER UNIT HAVING A RECESS EXTENDING FROM SAID FACE TO ALLOW THE WIRE PORTIONS THAT ARE TO BE TWISTED TO PASS INTO THE SLOT IN THE WIRE TWISTER PINION, THE PASSAGES IN SAID WIRE HOLDER DEVICE WHEN THE LATTER IS RAISED AS AFORESAID BEING ON A LEVEL WITH SAID RECESS.

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