US3196779A

US3196779A - Automatic strapping machine

Info

Publication number: US3196779A
Application number: US142040A
Authority: US
Inventors: Harold K Embree
Original assignee: Ovalstrapping Ltd
Current assignee: Ovalstrapping Ltd
Priority date: 1961-08-28
Filing date: 1961-10-02
Publication date: 1965-07-27
Anticipated expiration: 1982-07-27

Description

H. K. EMBREE AUTOMATIC STRAPPING MACHINE July 27, 1965 17 Sheets-Sheet 1 Filed Oct. 2, 1961 INVENTOR HAROLD K. EMBREE FW- K ATTORNEYS July 27, 1965 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, 1961 17 Sheets-Sheet 2 O 229- O O 2 v 1 INVENTOR HAROLD K. EMBREE BY-/XM W- ATTORNEYS July 27, 1965 H. K. EMBREE 3,196,77 9

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, 1961 17 Sheets-Sheet 3 INVENTOR HAROLD K. EMBREE BY- XM W' ATTORNEYS July 27, 1965 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, 1961 17 Sheets-Sheet 4 INVENTOR HAROLD K. EMBREE B Y- M ATTORNEYS 17 Sheets-Sheet 5 FIG. ll

INVENTOR HAROLD K. EMBREE M W,

ATTORNEYS July 27, 1965 H. K. EMBREE AUTOMATIC STRAPPING MACHINE Filed 001:. 2. 1961 July 27, 19,65 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, 1961 17 Sheets-Sheet 6 Q Q N n 2 .EL:

4 4 .L i 9 I N I 5 m Q I I g IH:

Inc

FIG. 7

use

INVENTOR HAROLD K. EMBREE.

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, E61 1'7 Sheets-Sheet 8 INVENTOR HAROLD K. EMBREE BY- M ATTORNEYS.

July 27, 1965 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE Filed Oct. 2. 1961 17 Sheets-Sheet 9 .FIG. 29

INVENTOR HAROLD K. EMBREE ATTORNEYS 17 Sheets-Sheet 10 Filed Oct 2, 1961 FIG/5 FIG. 28

INVENTOR HAROLD K. EMBREE MU TORNEYS July 27, 1965 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, 1961 17 Sheets-Sheet ll FIG/8 INVENTOR HAROLD K. EMBREE ATTORNEYS July 27, 1965 H. K. EMBREE 3,196,77

AUTOMATIC STRAPPING MACHINE Filed Oct. 2. 1961 17 Sheets-Sheet 12 Ll 3050 3050 607 g I 7911' 51/ pf r-\ -INVENTOR HAROLD K E MBREE July 27, 1965 Filed Oct. 2. 1961 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE 17 Sheets-Sheet l3 2O HAROLD K. EMBREE ATTORNEYS 17 Sheets-Sheet 16 H. K. EMBREE AUTOMATIC STRAPPING MACHINE sma' rEuly 27, 1965 Filed Oct. 2, 1961 a J F INVENTOR AROLD Kl W I) ,q a

July 27, 1965 H. K. EMBREE 3,196,779

AUTOMATIC STRAPPING MACHINE Filed Oct. 2, 1961 17 Sheets-Sheet l7 Map 1 Mg] XXW aoa aoz 80/ FIG. 24

INVENTYOR HAROLD K. EMBREE ATTORNEYS United States Patent HEAT:

3,196,779 AUTOMATIC STRAPPING MACHINE Hamid It. Emhree, I-Iamiiton, Gntario, Canada, assignor to Ovaistrapping Limited, Hamilton, Gutario, Canada I iied Oct. 2, 1961, Ser. No. 142,040 Claims priority, application Qanada, Aug. 23, 1961, 839,647, Patent 699,655 9 Claims. (Cl. Mitt-4) The present invention relates to automatic strapping machines of the type used for example for applying wire straps to bales of paper pulp.

The invention particularly relates to a fully automatic strapping machine which, when initiated, applies a strap in form of a loop to a package, tensions the strap about the package and knots the strap, all without the necessity of intervention by the operator.

In the past, wire tying machines have fallen into three general categories, firstly, the type where the strap is applied largely by the operator who manually operates hand tools to tension and knot the strap about the bale, secondly the type in which a loop is formed by a machine applied to the package and then tensioned and tied by the operator, and, thirdly the type in which a loop is formed by a machine and applied under tensions.

The devices of the prior art have suffered from several disadvantages not the least of which was a great waste of strapping material after the formation and severing of the strap. A disadvantage of the first two mentioned machines was that, owing to the bulk and clumsiness of the machines and the amount of manual exertion required by the operator in order to form the strap, operators were considerably fatigued after a working shift and production was relatively low for the length of man-hours involved in the operation, whilst a disadvantage of the further type of machine was that, owing to the strap being applied under tension the strapping curled. Thus when the strap was cut from the bale, it was often hazardous to the cutter because of the inherent uneven curl in the strap.

The present invention has to a very large extent overcome operator fatigue by providing a machine which is automatic and requires no effort on the part of the operator other than the pushing of a button to start the machine in order to cause the formation of straps about packages or bales.

Applicant has further overcome the disadvantages of the prior art by providing a machine in which substantially all of the strap applied about the package is used for the purpose of strap formation, thus eliminating waste of strapping material.

Still furthermore according to this invention, the strap is applied in an unstrained condition.

According to the present invention, an automatic strap applying machine for use with a reel of wire or the like comprises strap feeding means, loop forming means adapted to receive the wire from the feeding means and form a loop about the package when in place in the machine, strap tensioning means for tensioning the formed loop about said package and twisting means operable to form a knotting twist to overlapping ends of the loop, and cutter means operable to sever the knotted loop from the reel, all of which means are capable of being operated automatically and in a predetermined sequence.

A further feature of the present invention is to provide a conveyor means associated in a timed relationship with the strap applying machine in such a manner that a plurality of straps may be applied to a package in a predetermined sequence.

The following is a description by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a pictorial view of the strap applying device, certain parts having been removed for the purpose of illustration;

FIGURE 2 is a view of the console seen from the rear with the rear cover removed;

FIGURE 3 is a section through the feed and tensioning roll showing the details of the mountings of those rolls;

FIGURE 4 is a pictorial view of the loop-forming strapping guide mounted in its supporting frame;

FIGURE 5 is a schematic plan view 011 a distorted scale, of the loop-forming device indicating the manner in which the wire strap is caused to overlap for knotting;

FIGURE 6 is a detail of a corner of the loop-forming device;

FIGURE 7 and FIGURE 8 are front and side views, respectively, of the main frame and the linkage for moving the support frame and loop-forming guideway therewithin, part of the front panel of the main frame having been removed to illustrate parts of the guideway;

FIGURE 9 is a detail of a section taken on the line IX-IX in FIGURE 7;

FIGURES 10 and 11 are details of the stripping device taken on the section lines XX and XIXI of FIGURE 6 respectively;

FIGURE 12 is a front view of the gripper device;

FIGURE 13 is an end view of the same gripper device;

FIGURE 14 is a detail in lines XIVXIV of FIG- URE 13;

FIGURE 15 is an end view of the gripper from the end opposite that shown in FIGURE 13;

FIGURE 16 is a plan view of the gripper;

FIGURE 17 is a detail of the twister looking from the right as seen in FIGURE 1 and with the side plate removed;

FIGURE 18 is a plan view of the gripper and twister with the latter disengaged from the wire.

FIGURES 19 and 20 together form a schematic circuit diagram for the wire applying device;

FIGURES 21 and 22 are elevation and plan views of the conveyor device;

FIGURE 23 is a schematic illustration of the circuit diagram which can be roughly considered to continue beneath the diagram formed by FIGURES 19 and 20 but for the purposes of the description certain items in FIGURE 19 have been duplicated in FIGURE 23;

FIGURE 24 is a plan view of a wire arrester for the device as illustrated in FIGURE 1;

FIGURES 25, 26 are sections in the lines XXVXXV, XXVIXXVI respectively on FIGURE 24;

FIGURE 27 is a pictorial view of the links in the conveyor chain;

FIGURE 28 is a detail of the conveyor device;

FIGURE 29 is a detail of the cutter looking in the same direction as in FIGURE 7.

With the present embodiment of the invention a bale to be strapped is fed into strapping position within a rectangular loop forming frame. Wire strapping is automatically fed from a reel of wire into the loop forming frame. A loop is formed, is pulled out of the frame, which opens after the loop has been formed, the loop is tensioned about the bale, a knot is twisted in the strap and it is severed from the reel.

Turning now to FIGURE 1 it will be observed that a strap applying device according to the invention comprises basically a strap feeding and tensioning head 30, a loop forming guide member 32, a strap gripping head 34 and a strap twisting or knotting device 35.

Tension and feeding head A console panel 40 is located at one side of the loopforming guide member 32 and extending from the console panel is a motor-driven shaft 43 adapted to receive a a reel 44 of wire strapping 45. The drum is driven by a reversible motor 60 (see FIGURE 2) and the strapping 45 is adapted to be entrained over a guide roll 59 through a pair of ten-sioning rolls 51 to a pair of feeding rolls 55 by which it is fed into the loop-forming guide member 32.

The reversible motor 60 is coupled to the shaft 43 for the drum 44 through a gear box 61, gear wheel 62, chain drive 63 and gear wheel 64.

The tension and feeding head 30 on which are mounted the guide roll 50, the tensioning rolls 51 and the feed trolls 55 is slidably mounted in guideways on the front of the console 40 for reciprocation on the console 40 towards and away from loop forming guide member 32. A tension head pneumatic locking cylinder 65 engages a stop in the head at the front of the console and is operable to lock the head 30 in its outward position.

The lower tensioning and feeding rolls 51A and 55A are secured to the head 30 and move therewith. These rolls are driven by a motor 67 (FIGURE 2) through a belt drive 68, a sprocket 69 and a chain drive 79 through gears 71 and '72. The shaft 515 of the lower tensioning roll 51A is provided at its inner end with a sprag 638 (FIGURE 3) which permits of rotation of the roll 51A in one direction only. The shaft 518 is coupled to the sprag through the slip clutch 75 which is arranged to slip at a torque predetermined by a nut and washer arrangement 76 of known form. The shaft carries an arm 77 which is connected to a lever 78 (FIGURE 2) pivoted at 7-8P to the inside of the console front wall. The top of the lever 78 is arranged to contact a limit switch 320 when the head 30 moves towards the loop-forming guide member 32 due to the application of tension to the strapping sufiieient to cause the head 30 to walk along the strap and to overcome the bias of a compression spring (not shown). The purpose of the switch 320 and the movement of the head 30 to operate it will become apparent hereinafter.

The top rolls 51B and 55B are mounted on eccentric shafts (FIGURE 3) are driven through gears 51G, 51E and are rocked down into operative position with the rolls 51A and 55A by a pair of reciprocating

air motors

65 and 66 through levers 65C and 660 on actuation of the air motors.

Loop-forming guide The loop-forming guide member 32 (FIGURES 4, 5, 6, 7, 8) comprises a guideway 99 having a channel or groove 90C in its outer edge, which guideway 90 is securely mounted in a rigidi-fying frame 91 and arranged for bodily movement therewith within a main frame 92 towards and away from the front thereof. Guideway 90 comprises an entrance portion 95, a first upright portion 96, a top portion 97, a second upright portion 98 and a return portion 99. Reference to FIGURE will show that the entrance portion 95 and the return portion 99 are spaced apart from each other. The spacing is caused by the offset in the top portion 97 and this offset is exaggerated in FIGURE 5 for the sake of illustration. The dis tance D between the entrance portion 95 and the return portion 99 is in fact not much greater than the width of the strapping wire. This offset enables the return portion of the strap to be led behind the entrance portion of the strap and thus to provide at the centre of the bottom of the guideway a pair of parallel running strap sections which in the strap-ping operation are twisted to form a knot.

When the guideway 90 is in the forward or loading position the channel therein forms with the front panel 100 of the main frame a closed track for the strapping wire and the front panel 100 prohibits lateral movement of the strapping wire out of the channel.

The guideway 90 has rounded corners and at these corners recesses are cut into the outer surface of the guideway to receive the periphery of rollers 136 (see FIG- URES 6 and 11) mounted on the rigidifying frame 91. In this manner the strapping wire when being threaded into the channel 96C in the front face of the guideway i 99 has a relatively friction-free passage around the guideway since it runs on the rollers 136 at the corners.

The offset in the top portion 97 of the guide is compensated for by variation in thickness in the front plate 109A of the main frame 92 so that the front plate presents a flat and level configuration to an outside observer.

As best seen in FIGURE 7 (which shows the main frame with the left-hand lower side of the front panel 190 removed) a gap exists between the entrance portion 95 and the return portion 99 of the guideway and the entrance portion does not extend beyond the centre line of the guide member 32 in the direction of the feeding rolls. This gap is closed and the guideway 90 thus completed by a tiltable feeding track arm 105, biased downwardly by a spring 1055, and a gate 106 (see also FIGURE 9). The feeding track has a strapping-wire receiving-channel in its upper surface and it is into this channel that the strap is fed 'by the tension and feeding head 30 from the reel 44. The gate 106 has a lip in its inner surface to provide a complete loop-forming guideway for the strapping wire. The front run 45F of strapping wire, when it leaves the feeding track member 105, passes beneath a lip 106C of the gate 106 on top of an un er-guide 184- and is separated from the rear run of strapping wire 45B by a barrier or separator member 94.

The frame 91 is provided, as best seen in FIGURES 4, 6, 7 and 8 at each of its corners with outwardly extending stub shafts 116), 111, 112 and 113 which, when the frame 91 is in place on the main frame 92, extends through apertures in the side plates 1008 of the main frame (FIGURE 6).

The

stub shafts

110, 111, 112, 113 are connected externally of the main frame 92 to a linkage 115 comprising

links

116, 117, and 118. Links 116 and 117 are connected at their tops by a double crossbar 119 which through a shaft 119$ connects with a single crossbar 119A to the link 1 18.

Links

117 and 118 carry pivoted bell cranks 111B, 111C, 111D, 111E which engage

shafts

110, 111, 112, and 113. 'Link 116 is connected through bell crank lever 116C to an air motor 114. The frame '91 is mounted on rollers in the bottom of the main frame '92. One of the rollers 91R is seen in FIGURE 9. Op eration of the air motor 114 when a loop of strapping has been formed causes the link 116 through

crossheads

119 and 119A to move

links

117 and 118 which through bell crank levers 111B, 111C, 111D, 111E bodily displace the frame 91 with its guideway 90 com-prising its entrance portion 95, upright portion 96, top portion 97, second upright portion 98 and return portion 99, backwards on the rollers 91R within the main frame 92 away from the front plate 109A. At the same time, the frame 91 carries back with it a depending member 108 (FIGURE 9) which :pulls on the link 109 to rock the link 107 and thus the gate 106 is rocked back clear of the front run of strapping wire 45F and leaves this run resting on the guide 164.

Mounted around the periphery of the frame 91 are a plurality of stripping pins 120 for stripping the formed loop from the guideway 90. These pins are completely free to slide in slots 121 (see FIGURES 6 and 10) in housings 122 on the rigidifying frame 91 and in slots 123 in the guideway 90. The pins extend beyond the frame at front and rear so as to be constrained Within the main frame 92 by the front plate 100A and the rear plate 100B thereof. The pins 120 are undercut rearwardly at 125 and extend into the path of the guide channel 900 the undercutting providing for the loading of the straps into the channel 90C of the guide 90 when the frame 91 is in the forward position. It will be seen that when the frame 91 is rn oved rearwardly within the main frame 92 by the action of the air motor 114 the pins 120 cannot move since they abut against the rear plate 100B and thus the guide 90 moves relatively to the pins 120 and the notches 125 in the pins, which engage the strapping wire in the channel 900, strip the strapping from the channel 90C of the guide 98. It is in this manner that the strap formed into loop configuration is removed from the loop-forming device 32. This stripping action is assisted by the spring loaded corner rollers 139 (FIGURE 11) which are biased outwardly of the frame 91 by springs 131. When the frame 91 is in the forward position the rollers 13% are retracted in their housings 134 and offer a smooth periphery 135 to the wire 45 in the channel 98C so that they cooperate with the fixed rollers 136 in providing for a smooth corner passage for the strapping wire but when the frame 91 is moved rearwardly the flanges 137 on the rollers 130 assist the stripping pins to expel the strapping wire from the channel 90C and to allow the removal of the excess strapping formed in the loop so that it conforms to the sides of the package before the centre portion of the wire is released onto the bale.

In order to ensure that the strapping wire is free of the guideway 90 at all points before it is pulled, by the action of the tension rollers 51 onto a package, a retaining device 886 (FIGURES 1, 24, 25, 26) is provided to momentarily restrain the strap after stripping.

The retaining device Silt) comprises an endless tubular member 861 which provides a pair of closely arranged stops 892, 803 which extend across the front of the strapping device and encircle the upright sides thereof. A pair of perforated racks, one of which is shown in FIGURE 1 and indicated as 805, are provided, one on each side of the strap applying device and the height of the member 8811 of the device can be adjusted merely by removing the pins 866 and moving the member 801) up or down and replacing the pins 806 in selected holes. It is necessary to adjust the height of the retaining member 868 in order to accommodate different size of bales. When the wire has been stripped from the guide member it falls between the stops 802, 883 and is momentarily arrested by the action of the plunger 807 against the depending face 808 until the action of the tension rollers 51 pull the strap past the plunger 807 and onto the package.

The gripper The gripper head 34 (FIGURES 12 through 16) is located at the centre of the loop-forming guide member 32 on a base plate 150 having a front wall tlF and side walls 1508. The base plate 150 has vertical gibs 151 extending upwardly therefrom behind the front wall 1561 A supporting frame 152 is mounted for vertical reciprocation in the gibs 151. The supporting frame 152 is vertically reciprocated by the piston and cylinder air-motor 153. The extremity of the piston rod 153R is provided with a clevis 154 to which is attached a link 1155 connected to shaft 156. Mounted on the shaft 156 is a link 157 having a bifurcated end 158 which engages with a crank pin 159 on the supporting frame 152. Extension of the piston rod 153R in the cylinder 153 rocks the link 155, the shaft 156 and the link 157 to raise and lower the supporting frame 152 in the gibs 151.

Connected to the top of the supporting frame 152 is a transversely extending shaft 160. Mounted on the shaft 168 so that it may rock about the axis thereof relative to the supporting frame 152 is a gripper head assembly 161. The gripper head assembly 161 comprises: a fixed upper gripper jaw 162, having a stop face 162F; a tilting frame 163, to which the jaw 162 is firmly connected and a movable lower jaw 164. The jaw 164 is raised and lowered into closed and open position by a pneumatic cylinder and piston arrangement 165. The clevis 167 on the outer end of the piston rod of this arrangement is connected through a clevis pin 170 to a link 168 which is connected through an eccentric 169 to the jaw 164 (FIGURE 14). Actuation of the cylinder 165 causes the rocking of the arm 168 on the eccentric 169 about a pivot point 1681 providing for the raising and lowering of the gripper jaw 164.

Extending from the rear of the clevis pin 170 is a conical cam engaging surface 171 (FIGURES 13, 15 and 16) rigidly secured to the base plate is a projecting bracket 172 carrying a cam face 175.

The gripper assembly 161, in addition to being mounted for rocldng action about the shaft is also arranged for limited axial movement on the shaft against the bias of the spring 175. On the end of the shaft 160 remote from this spring 175 is provided a bracket 176 carrying a switch 395 which is actuated by a trip element 177 on the frame 163. Thus, relative movement of the frame 163 axially of the shaft 160 to the switch 395 (caused by the action of the leading end of the strapping wire being fed into the gripper assembly 161 to abut against the stop face 162F) causes the member 177 to engage and trip the switch 395.

Extending across the front of the supporting frame 152, and rigidly attached thereto, is a projecting member 180 to which is attached a bushing 180B carrying a goosenecked guide finger 181 mounted for rocking about the bar member 180 and spring biased by a torsion spring 1818 into a normally inward position. The goose-necked guide finger 181 is provided with a slot 185 which engages the front run 45F of the wire 45 in the guide member 32 through slot 1068 in the gate 106. Also attached to the frame 152 at the end remote from the guide finger 181 is a front lift finger 186 for the front run 45F of the strapping wire. Behind and pivotally attached to the finger 186 is a rear lift finger 187 (FIGURE 15) provided with a strapping wire engaging slot 188 and a bumper pad 189.

Mounted on the back of the tilting frame 163 is a switching arm 190 connected to the eccentric 169 and a switch 19].. Operation of the piston and cylinder anrangement 165 to rock the arm 168 to open the jaw 164 causes the switching arm 190 to engage with a trip the switch 191 for a purpose which will become apparent hereinafter.

Mounted on the base plate 150 at the rear thereof is a switching panel 193 carrying three

switches

328, 329, 397 operated by a cam bar 197 having three switch tripping cams 328e, 3290, 397a thereon. The cam bar 197 terminates in a bifurcated link 197L which is connected to the lower end of a bell crank lever 198. The bell crank lever 198 is pivoted at 198p to the the panel 193 and at its upper end is connected to the pin 199, and then through a crank lever 200 to the shaft 156. Thus, when cylinder 153 rocks the shaft 156, it, in turn, moves the cam bar 197 through the bell crank lever 198 to slide the cam bar 197 so that the

switches

328, 329, 397 are operated by their tripping cams.

Secured on the frame 163 adjacent the gripper jaw 162 is a hollow trunnion 205 (best seen in FIGURE 13) which carries a guide lever 206 pivotally mounted thereon. At the lower extremity of the guide lever 206 is a roller 2117. Midway on the lever is a slot 208 which engages with a stub shaft 209 which is fixed to the frame 163. Adjacent this point the lever is engaged by a spring pressed plunger 210 housed in a bracket 211 on the frame 163. The guide lever 206 functions to return the gripper head assembly to the upright position at the end of the strapping operation as will become apparent hereinafter.

The twister The twister assembly 35 (see FIGURES 1, 17 and 18) is mounted on a base in gibs 216 in the floor plate 210P (FIGURE 17) and is reciprocated in the gibs 216 by a pneumatic motor 217 (FIGURE 18) through a linkage 218 to move into and out of engagement with the front and rear strapping

wires

45F and 45B. An upstanding plate 211 is located centrally of the assembly 35 to carry on one side the motor 212 which during operation is normally running in one direction. A belt drive connection is made from the motor 212 with a shaft 213 through an electrical clutch 214 to drive the driving gear 221) (FIGURE 17). The driving gear 220 drives, through an idler 221, a large gear 222 which in its turn, through a pair of small idler gears 225, 226 drives the twisting pinion

Claims

2. AN AUTOMATIC WIRE STRAPPING MACHINE FOR USE WITH A WIRE DISPENSING REEL COMPRSING LOOP-FORMING MEANS, MEANS FOR FEEDING THE WIRE FROM SAID DISPENSING REEL TO SAID LOOP-FORMING MEANS BY THREADING A FREE END OF THE WIRE FROM THE DISPENSING MEANS INTO GUIDEWAYS IN SAID LOOP-FORMING MEANS, STOP MEANS INCLUDING A GRIPPER ELEMENT ADAPTED TO ENGAGE AND GRIP SAID FREE END, SWITCH MEANS OPERATED BY MOVEMENT OF THE STOP MEANS ON ENGAGEMENT WITH SAID FREE END TO CAUSE A CESSATION OF THE THREADING OF THE WIRE, SWITCH MEANS OPERABLE TO CAUSE THE STRIPPING OF THE FORMED LOOP FROM THE LOOP-FORMING MEANS, SWITCH MEANS OPERABLE BY MOVEMENT OF THE LOOPFORMING MEANS TO INITIATE MEANS TO APPLY TENSION OF THE WIRE TO DRAW TAUT ABOUT A PACKAGE, TWISTER MEANS AND SWITCH MEANS OPERABLE TO CAUSE THE TWISTER MEANS TO ENGAGE THE WIRE AND KNOT IT, AND MEANS TO SEVER THE WIRE FROM THE WIRE DISPENSING REEL AND RELEASE THE LOOP FROM THE GRIPPER ELEMENT.