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Contents
1. Primary Examiner David Martin 567 568 1 569 626 445 449 450 466 470 Artomey Agent Firm Crutsinger amp Booth 362 364 365 57 ABSTRACT 56 References Cited A bag neck tying device for tying a ribbon dispensed from U S PATENT DOCUMENTS a spool about a gathered neck A pulley and proximity switch 3 059 670 10 1962 Burford et al are mounted to prevent the completion of a tying cycle if a 3 138 904 6 1964 Burfod bag neck is not properly gathered and ready to be tied 3 583 131 6 1971 Gaudlitz eere 3 648 432 3 1972 Zellmer et al 11 Claims 13 Drawing Sheets 19 5 708 339 Sheet 1 of 13 Jan 13 1998 U S Patent U S Patent Jan 13 1998 Sheet 2 of 13 5 708 339 88 lij eee ow 5 0 6 9 2 2 gt ete 2 5 708 339 Sheet 3 of 13 Jan 13 1998 U S Patent t DIH 5 708 339 Sheet 4 of 13 Jan 13 1998 U S Patent FIG 4 U S Patent Jan 13 1998 Sheet 5 of 13 5 708 339 FIG 5 5 708 339 Sheet 6 of 13 Jan 13 1998 U S Patent 97014 vs 11 U S Patent Jan 13 1998 Sheet 7 of 13 5 708 339 U S Patent Jan 13 1998 Sheet 8 of 13 5 708 339 BVDC 470 2W 34VDC 2 0 34VDC FIG 8 Tl YEL 117VAC 24VAC WHT BLK2. A U S Patent Jan 13 1998 Sheet 9 of 13 5 708 339 MOTOR 2 OUTPUT lt E 5 lt ce zu oc OL lt Ed 2 S3 8 10K 2 5 als ae oo ON 4 CHI 9 U S Patent Jan 13 1998 Sheet 10 of 13 5 708 339 FIG 10 91 MJ11033 HMLP1700 34VDC OE I X 9 U S Patent Jan 13 1998 Sheet 11 of 13 5 708 339 1400 1600 z m n J tri 1 eee TT NUN NE T 0 02 04 06 08 10 12 14 16 18 20 22 24 26 28 0 SECONDS FIG 11 U S Patent Jan 13 1998 Sheet 12 of 13 5 708 339 U S Patent Jan 13 1998 Sheet 13 of 13 5 708 339 c 75a 66 5 708 339 1 BAG NECK GATHERING STOP This is a division of application Ser 08 129 284 filed Sep 30 1993 now U S Pat No 5 483 134 TECHNICAL FIELD The invention relates to apparatus for wrapping a ribbon around the gathered neck of a bag and twisting the ribbon for closing and sealing the neck of a flexible bag BACKGROUND OF INVENTION US Pat No 3 138 904 to Earl E Burford entitled METHOD AND APPARATUS FOR TYING PACKAGES AND WRAPPING MATERIALS U S Pat No 3 059 670 to Charles E Burford and Leonard W Burford entitled WIRE TWISTING TOOL U S Pat No 3 919 829 to Leonard W Burford and Charles C Burford entitled APPA RATUS FOR TYIN
3. i l US005708339A United States Patent 11 Patent Number 5 708 339 Frazier et al 4 Date of Patent Jan 13 1998 54 BAG NECK GATHERING STOP 3 721 061 3 1973 3 825 039 7 1974 75 Inventors Jimmy R Frazier Norman John D 3 919 829 5 CREE 4531905 91985 Hoyland 53 131 j ovlalid Norman Okla 4 586412 5 1986 Johnson 01 4 730 434 3 1988 Knudsen e 53 67 73 Assignee Burford Corporation Maysville Okla 4 856258 8 1989 Burford et al 53 138 A 4 868 759 9 1989 Ross et al eere 53 51 21 Appl No 583 567 5 121 682 6 1992 Parker et al 53 138 8 5 138 815 8 1992 Groschen Jr 5 22 Filed Jan 5 1996 5 194 793 3 1993 Niimi 318 568 15 p 5 347 791 9 1994 Ginzl et al e 53 450 Related U S Application Data 5 483 134 1 1996 Frazier et al 318 468 62 Division of Ser No 129284 Sep 30 1993 Pat No OTHER PUBLICATIONS 5414 Motorola 3 068332 SIM User s Manual Motorola Inc SIF Int CES SRS aa 6058 5 00 1989 52 10 8 aa 318 468 318 626 318 364 Hewlett Packard 56mm Diameter Two and Three Channel 53 138 8 53 583 Incremental Optical Encoder Kit HEDS 6000 Series pp 58 Field of Search 53 138 1 138 3 1 8 Pub No 5954 8420 Mar 1987 53 138 6 138 8 139 4 203 583 318 560 1
4. feedback concept for operation and the output PWM signals are forced to a pre assigned function of the reference input of the microcontroller of the central processing unit The microcontroller 96 sends control PWM signals determined by the programmed movements stored in RAM memory in a pre assigned order as a function of time after switch arm 88 returns to its home position illustrated in FIG 3 The contro PWM signals are delivered to the control circuit Each encoder 1 4 connected to the shaft of motors 1 send quadrature signals to the decoders D1 D4 that indicate the position of the shaft of each motor The control PWM signals delivered to each control circuit 1 4 are delivered to motor drivers 91 94 The quadrature signals from decoders 51 54 are read to adjust the control PWM signals Drivers 92 93 and 94 which control the delivery of power to motors M2 M3 and M4 respectively for control ling the needle assembly 40 twister hook assembly 50 and holder shear mechanism 60 are substantially identical One side of the winding of each of the motors M2 M3 and M4 is connected to ground Drivers 92 93 and 94 deliver either positive or negative power to the other side of the motor winding for driving motors M2 and in opposite directions For example when positive 34 volt direct current is delivered to the winding of motor M2 its shaft is driven in a clockwise direction If negative 34 volt direct current is d
5. parallel light An emitter end plate contains two or three similar light sources one for each channel The code wheel is a metal disc that has N equally spaced slits around its circumference An aperture with a matching pattern is positioned on a stationary phase plate The light beam is transmitted only when the slits in the code wheel and the aperture line up therefore during a complete shaft revolution there will be N alternating light and dark periods 15 25 45 55 65 8 A molded lens beneath the phase plate aperture collects the modulated light into a silicon detector The encoder body contains the phase plate and the detec tion elements for two or three channels Each channel consists of an integrated circuit with two photo diodes and amplifiers comparator and output circuitry not shown The apertures for the two photo diodes are positioned so that a light period on one detector corresponds to a dark period on the other The photo diode signals are amplified and fed to a comparator whose output changes state when the difference of the two photo currents changes sign The second channel has a similar configuration but the location of its aperture pair provides an output which is in quadrature to the first channel phase difference of 90 Direction of rotation is determined by observing which of the channels is the leading waveform The outputs are TTL logic level signals The motion sensing application and enco
6. explained one of the pulleys 41 41a or 41b is preferably equipped with a sensor device which is capable of calculating the amount of ribbon 15 dispensed from spool 41c The sensor apparatus deter mines whether or not a bag neck is present As needle 41 moves from the full outline position illustrated in FIG 2 to the dashed outline position if a bag neck is not positioned in the path of the ribbon the cycle of operation will be interrupted so that the holder shear assembly 60 will not be actuated and the twister hook assembly 50 will not rotate This prevents actuation of the holder shear assembly which would have resulted in the ribbon being dropped or released if a bag neck was not present The frame of the bag tying device may assume many configurations In the illustrated embodiment upper and lower face plates 16 and 17 are supported on forward edges of vertically extending end plates 18 and 19 having slots formed therein to permit passage of a bag neck A horizontal mounting plate 19 extends between lower portions of end plates 18 and 19 and a vertical mounting plate 16a extends outwardly from end plate 18 A motor M1 having an encoder E1 mounted the rear end of motor M1 is mounted on an upper portion of the vertical mounting plate 16a for driving the gathering assembly 20 A motor M2 having an encoder E2 mounted the rear end and a gear box 46 mounted on the front end of motor M2 is mounted on an upper portion of the rear surface
7. so that the invention may be better and more fully understood in which FIG 1 is a perspective view illustrating the front of the bag neck tying device FIG 2 is a diagrammatic front elevational view FIG 3 is a diagrammatic rear elevational view FIG 4 is an end view looking generally in the direction of the arrows along line 4 4 in FIG 2 FIG 5 is a diagrammatic end view illustrating the dis charge end of the bag neck tying device looking in the direction of the arrows along line 5 5 in FIG 2 FIG 6 is a top plan view looking in the direction of the arrows along line 6 6 in FIG 2 parts being broken away to more clearly illustrate the details of construction FIG 7 is a wiring diagram of the closed loop microcom puter controlled control system FIG 8 is a schematic diagram of the full wave rectified 8 and 34 volt power supply FIG 9 is a schematic diagram of a bi directional DC motor controller FIG 10 is a schematic diagram of a single direction DC motor controller FIG 11 is a graphic representation of the sequence of operation of the needle hook and shear assemblies during a complete cycle of operation FIG 12 is a diagramatic front elevational view of the tying device with belt guards and covers in position illus trating a spool of ribbon FIG 13 is a diagramatic perspective view of a pulley and proximity switch and FIG 14 is a perspective view of a holder shear assembly Numeral references a
8. with the addition of a biasing mecha nism connected between said shaft and said frame to resil iently urge said bag stop toward a predetermined home position 6 Bag neck tying apparatus comprising a frame having a slot defining a path a source of ribbon for dispensing a strand of ribbon having a free end and a central portion a holder shear assembly on said frame for cutting the ribbon and holding the free end of said ribbon 5 708 339 13 a needle assembly movably secured to said frame for engaging and positioning said central portion of said ribbon adjacent said holder shear assembly atwister assembly movably secured relative to said frame having a hook adjacent said holder shear assembly a bag stop lever mounted on said frame biasing means mounted between said frame and said bag stop lever for resiliently urging said bag stop lever toward a home position extending across said path an electric brake for locking said bag stop lever in said home position such that a bag neck moves into engage ment with said bag stop lever for gathering material a timer for energizing said electric brake to momentarily lock said bag stop in said home position and to de energize said electric brake at the expiration of a predetermined time period a plurality of electric motors said electric motors having drive shafts connected to each of said holder shear assemblies needle assembly and twister assembly encoders connected to each
9. 3 of the drawing roller 41 has a plurality of index points 41x In the illustrated embodiment the index points are formed by steel dowel pins circumferentially spaced around the axis about which roller 41 rotates A proximity switch 41s is positioned near index pointers 41x for mailing an electrical circuit when the presence of an indexing pin 41x is sensed The proximity switch 41s is of conventional design and is connected through a suitable power supply and amplifier to the CPU 96 Thus the CPU monitors the proximity output and counts the pulses produced by index pins 41x in roller 41 The CPU 96 calculates the amount of ribbon dispensed to determine 10 15 35 45 55 65 6 whether or not a bag neck is present as needle 42 moves from the full outline position illustrated in FIG 2 of the drawing toward the dashed outline position illustrated in FIG 2 of the drawing If needle 42 did not wrap ribbon around a bag neck the CPU will terminate a portion of the remainder of the cycle of operation so that holder shear 65 will not be actuated to prevent releasing the end of ribbon 15 which is gripped between gripper finger 64 and anvil 68 or 69 Referring to FIGS 1 2 and 3 of the drawing a bag stop lever 80 is mounted on shaft 85 for rotary movement about a horizontal axis Shaft 85 extends through an electric brake 82 and has a crank arm 85a secured thereto which is resiliently urged in a clockwise direction as viewed i
10. 332 MCU The CPU Reference Manual describes the operation programming and instruc tion set of the CPU32 processor used in the MC68332 The Time Processing Unit Reference Manual describes the autonomous timer system used in the MC68332 The MC68332 microcontroller 96 contains intelligent peripheral modules such as the time processor unit CYPU which provides 16 microcoded channels for performing time related activities for simple input capture or output capture to complicated motor control or pulse width modu lation High speed serial communications are provided by the queued ser al module QSM with synchronous and asynchronous protocols available Two kilobytes of fully static standby RAM allow fast two cycle access for system and data stacks and variable storage with provision for battery backup Twelve chip selects enhance system inte gration for fast external memory or peripheral access These modules are connected on chip via an intermodule bus IMB The Mc68332 microcontroller 96 is a 132 pin plastic quad flat pack that operates at a frequency of 16 78 MHz with a 5 volt supply and is software programmable It has 16 independent programmable channels and pins Any channel can perform any time function including input capture output compare or pulse width modulation PWM The detailed logical procedures or algorithms processed by the microcomputer are proportional integral derivative PID type control mode signals The PID control m
11. 5 of the gathered neck After the gathered neck passes lever 80 the lever 80 moves back to the illustrated position extending across path 12 Aneedle assembly 40 best illustrated in FIGS 1 4 and 7 is positioned for wrapping a strand 15 of ribbon material around a gathered neck of a bag The needle assembly 40 comprises a needle 42 carrying idler rollers 44 44a and 445 The needle 42 is mounted on the output shaft 45 of a gear box 46 driven by motor M2 Needle 42 is shown in its home position in FIGS 1 and 2 of the drawing Motor M2 moves needle 42 from the full outline position to the dashed outline position illustrated in FIG 2 of the drawing and then reverses for moving the needle 42 back to the position illustrated in full outline in FIG 2 Referring to FIGS 1 3 and 7 of the drawing a twister hook assembly 50 comprises a twister shaft 52 rotatably mounted in a bearing 53 having a hook 54 on one end thereof and a pulley 55 on the other end A drive pulley 56 is mounted on the drive shaft of motor M3 and drives pulley 55 through a belt 58 As best illustrated in FIGS 1 2 5 7 and 14 of the drawing a ribbon holder shear assembly generally desig nated by the numeral 60 comprises a holder and shear assembly of the type disclosed in U S Design Pat No 307 281 to Charles E Burford and U S Pat No 4 856 258 entitled WIRE TYING DEVICE which issued Aug 15 1989 to Charles E Burford and Jimmy R Frazier The holder shear a
12. C for interfacing to Motorola and Intel microprocessors can be found at page 1 61 through page 1 76 of Hewlett Packard Publication for HCTL 2000 HCTL 2016 HCTL 2020 Decoders D1 D4 have pins for a channel and channel B Schmitt trigger inputs which accept the outputs from quadrature encoders 51 54 The two channels are prefer ably 90 out of phase Controller The system is controlled by a computer 95 illustrated in FIG 6 which receives and stores a set of instructions and then acts upon the instructions in a predetermined and predictable fashion A microprocessor 96 is attached to a printed circuit board into which a thin layer of metal has been applied and then etched away to form traces The electronic components of the central processing unit are attached to the board with solder so that they can change electronic signals through the etched traces on the board 5 708 339 9 A suitable 32 bit integrated microcontroller 96 is the MC68332 which is commercially available from Motorola Inc of Schaumburg as a product referred to as MC68332 SIM System Integrated Module A complete documentation package of the MC68332 consists of the SIM 32UM AD MC68332 System Integration Module User s Manual the CPU32RM AD CPU32 Reference Manual and the TPU32RM AD Time Processing Unit Reference Manual The MC68332 System Integration Mod ule User s Manual describes the capabilities register and operation of the MC68
13. G PACKAGES AND WRAPPING MATERIALS and U S Pat No 4 856 258 which issued Aug 15 1989 to Charles E Burford and Jimmy R Frazier entitled WIRE TYING DEVICE disclose apparatus used for closing a plastic bag by attaching and twisting a wire like ribbon about the neck of the bag Bag tying devices of the type disclosed in the aforemen tioned patents are commercially available from Burford Corporation of Maysville Okla The tying devices are generally constructed to receive packages such as loaves of bread at speeds of for example one hundred 100 packages per minute The design of the bag tying devices requires careful consideration of the mass acceleration deceleration and momentum of the moving parts of the tying device Further precise synchronization of paris in subassemblies of the tying devices must be maintained throughout a tying cycle if the device is to operate effectively SUMMARY OF INVENTION The bag neck tying device disclosed herein incorporates a bag neck gathering mechanism comprising motor driven gathering belts for moving a bag neck along a path in a plane into engagement with a bag stop controlled by an electric brake positioned adjacent a ribbon holder shear assembly which holds the free end of a ribbon of He material A motor driven needle wraps the strand of tie material around the gathered neck of the bag and a motor driven twister hook assembly engages the free end and the running end of the ribbon adja
14. aid stop lever for momentarily locking said stop lever in a home 35 14 position such that material is gathered adjacent said lever when said brake is energized a timer connected to said switch and said brake for de energizing said brake after expiration of a predeter mined period of time and a proximity switch adjacent said ribbon in an electrical circuit connected to said electrically driven holder shear assembly to prevent actuation of said holder shear assembly if said needle assembly fails to pull ribbon from said source of ribbon to wrap ribbon around gathered material adjacent said twister assem bly 9 Bag neck tying apparatus according to claim 8 said holder shear assembly comprising a mounting plate a gripper arm a gripper finger on one end of said gripper arm means for rotatably securing said gripper arm to said mounting plate a pair of anvils on said mounting plate each of said anvils being associated with shear surfaces to grip and cut a strand of ribbon positioned between one of said anvils and said gripper finger and an electric motor drivingly connected to said gripper arm for moving said gripper finger to cut and grip said ribbon 10 Bag neck tying apparatus according to claim 8 said needle assembly comprising a needle an idler roller on said needle an electric motor having an output shaft and a gearbox drivingly connecting said needle to said motor output shaft 11 Bag neck
15. cent the gathered neck for twisting the ribbon Independently controlled bi directional brush type ser vomotors are mounted in the separate subassemblies of the tying device Each of the servomotors is controlled by a solid state DC motor controller in a closed loop feedback system under the control of a multi channel microcontroller which precisely starts controls and stops each of the ser vomotors in a pre assigned sequence for each cycle of the tying apparatus The weight and number of moving parts in the tying device have been significantly reduced More particularly the software driven motor controllers isolate the movement of the various components of the tying device to reduce stress and shock loading of parts of mechanical drive trains A preferred embodiment of the apparatus for securing material includes improvements in apparatus for gathering material such as plastic bag material or a variety of other materials such as coils of electrical cord water hose tubing yarn and bundles of cable rods or carrots and in apparatus for fastening the gathered material It is contemplated that 10 15 35 45 55 2 the disclosed closed loop control circuit may be used to control electric motors to drive apparatus for fastening gathered materials in addition to the specific disclosed embodiment of the bag neck tying device DESCRIPTION OF THE DRAWINGS Drawings of a preferred embodiment of the invention are annexed hereto
16. circuit C4 which will energize motor M4 for rotating cam 70 to move the gripper finger 64 to release the free end of the ribbon and shear a segment from the end of the strand of ribbon At a time controlled by the software a signal will be delivered to motor M2 for moving needle 42 from the position shown in dashed outline in FIG 3 back to its home position A signal will be delivered to motor M3 for rotating twister hook 54 two revolutions in the reverse direction for slinging the tie which has been twisted around the neck of a bag out of the twister hook 54 for completing a tying cycle It should be readily apparent that when the neck of a bag moves between gathering belts 22 and 32 switch arm 88 will be moved downwardly from the position illustrated in FIG 3 which will energize electric brake 82 so that belts 22 5 708 339 11 and 32 will move the neck of the bag into engagement with bag stop 8 causing the neck to be gathered As the trailing edge of the neck of the bag passes over the end of switch arm 88 switch arm 88 will move back to the position illustrated in FIG 3 causing switch 86 to send a signal to the micro controller for starting a new tying cycle A schematic diagram of a motor controller 92 is illustrated in FIG 9 of the drawing The optic coupler C6 delivers a PWM signal to the positive terminal CH1 from driver circuit C2 with reference to the negative terminal CH1 The positive terminal CH1 is connected through r
17. der interface circuitry will determine the need for relating the index pulse to the main data tracks A unique shaft position is identified by using the index pulse output only or by logically relating the index pulse A and B data channels The index pulse can be uniquely related to the A and B data tracks in a variety of ways Statewidth pulse width or edge transitions can be used The two square wave signals in quadrature of channels A and and a 5 volt supply input are delivered through a 10 pin connector to a corresponding decoder D1 D2 D3 or D4 mounted on an auxiliary board as illustrated in FIG 7 of the drawing Tines connecting encoders E2 to a decoder D2 are illustrated Encoders E3 and E4 are similarly con nected to decoders D3 and D4 Decoders Quadrature decoders D1 D4 are CMOS complimentary metal oxide semiconductor integrated circuits that perform the quadrature decoder counter and bus interface functions HTCL 2000 commercially available from Hewlett Packard quadrature decoder counter interface IC decoder interfaces an encoder to a microprocessor and is designed for use in digital closed loop motion control system and digital data input system The decoder includes a 4X quadrature decoder a binary up down state counter and a 16 bit bus interface A Schmitt triggered CMOS input and input noise filters are incorpo rated in the device Further information regarding the quadrature decoder counter interface I
18. e tied As best illustrated in FIGS 3 and 5 of the drawing driven shaft 25 having driven pulley 24 mounted on one end has a pulley 23 mounted on its opposite end Driven shaft 35 having driven pulley 34 mounted on one end has a pulley 33 mounted on its opposite end A pulley 30 mounted on the drive shaft of motor M1 drives pulleys 23 and 33 through a belt 31 such that driven pulley 24 rotates in a clockwise direction while driven pulley 34 rotates in a counter clockwise direction as viewed in FIG 2 of the drawing Belt guards 16a and 16b and 17a preferably extend between the gathering belts and products on the conveyor as illustrated in FIG 12 The bag neck is moved into a slot in the belt guard by brushes not shown and the product in the bag engages the belt guards when the neck of the bag is drawn by gathering belts 22 and 32 around a bag stop lever 80 It should be appreciated that other and further gathering struc tures may be used to form a gathered neck on a bag Terms such as left right clockwise counter clockwise horizontal vertical up and down when used in reference to the drawings generally refer to orientation of the parts in the illustrated embodiment and not necessarily during use These terms used herein arc meant only to refer to relative positions and or orientations for convenience and are not to be understood to be in any manner otherwise limiting As illustrated in FIGS 7 and 10 of the d
19. ed that other motors and motors of other sizes may be provided to facilitate driving the various assemblies For example it is contemplated that smaller motors would be used in a counter top model used for gathering and fastening materials such as coils of electrical cord water hose tubing or yarn and bundles of cable rods or carrots and other produce One side of the armature winding of each motor M1 M2 M3 and M4 is connected to ground such that reverting the polarity of current through the armature winding reverses the direction of rotation of the motor Each of the motors M1 M2 M3 and M4 has an encoder E1 E2 E3 or Ed mounted on its drive shaft which delivers an electrical signal to a decoder D1 D2 D3 or D4 which is representative of the position of the motor shaft Motor Controller Referring to FIGS 7 and 8 of the drawing the numeral 90 generally designates a power supply for delivering electric current to motor controller 91 and to motor M1 in the bag neck gathering mechanism 20 motor controller 92 and motor M2 in the needle assembly 40 motor controller 93 and motor M3 in the twister assembly 50 and motor controller 94 and motor M4 in the holder shear assembly 60 Referring to FIG 8 of the drawing the power supply 90 5 708 339 7 comprises a pair of single phase doughnut transformers T1 connected in parallel The supply or primary circuits of transformers T1 are connectable to any suitable source of electricit
20. elivered to the winding of motor M2 its shaft will be driven in a counter clockwise direction The driver 91 for motor M1 connected to the bag gath ering assembly 20 is similar to drivers 92 93 and 94 except that drier 91 is not provided with the capability of delivering negative direct current because it is not necessary for motor M1 to be driven in reverse Software is stored in FEEPROM memory on the CPU board for controlling the acceleration speed and position of the shaft of each motor 1 34 4 FIG 11 is a graphic representation of the sequence of operation of the needle hook and shear assemblies during a complete cycle of operation The microcontroller 96 is initially programmed by a computer through a serial port RS for storing a program which will initiate movement of needle 42 from its home position illustrated in FIG 3 and the speed of movement toward the dashed outline position illustrated in FIG 3 controlled by signals delivered through control circuit C2 to motor M2 While needle 42 is moving from the position illustrated in full outline toward the position illustrated in dashed outline the program causes a signal to be sent from control circuit C3 to motor M3 to begin rotating twister hook 54 and continue rotation of twister 54 a predetermined number of revolutions controlled by the motion profile in RAM memory Similarly when needle 42 and twister hook 54 are in predetermined positions a signal will be sent from driver
21. esistor R14 resistor R15 and diode D11 to the base terminal of high rail MPS651 transistor Q7 The negative terminal CH1 is connected through resistor R18 to the base of 2N2222A transistor 11 and through a 750 ohm resistor R92 to a negative 8 volt terminal and to the emitter of transistor 11 A 56 ohm resistor R22 forms a shunt between the base and emitter of transistor The collector of transistor is connected between resistors R14 and R15 The 1 ohm resistor R15 is connected through HMLP1700 diode D13 to the base of low rail MPS751 transistor Q9 Transistor Q11 turns off and on to turn transistors Q7 and Q9 off and on which in turn turn the high rail MJ11033 power transistor Q5 and the low rail MJ11032 power tran sistor Q13 off and on The collector of high rail transistor Q7 is connected through a 300 ohm 5 watt resistor R11 to the base of high rail power transistor Q5 The emitter of high rail transistor QS is connected to a 34 volt DC terminal while the collector of power transistor Q5 is connected through an MR822 diode D9 to a line connected to one side of the winding of motor M2 The collector of low rail transistor Q9 is connected through a 300 ohm 5 watt resistor R20 to the base of low rail power transistor Q13 The emitter of low rail power tran sistor Q13 is connected to a 34 volt DC terminal while its collector is connected through MR822 diode D16 to the line connected to one side of the winding of motor M2 Whe
22. f the wire like material about the gathered neck of the bag and twister hook 50 is actuated for twisting a portion of the wire like material about the neck of the bag 125 It should be noted that the ribbon of material 15 may be constructed of wire enclosed in paper or plastic or it may comprise a ribbon of plastic or any other material The strand of ribbon 15 extends around one or more pulleys 41 41 and 415 mounted on shafts 41a from a spool 41c of tie material as best illustrated in FIG 12 The mounting for spool 41c is similar to that disclosed in U S Pat No 3 919 829 entitled APPARATUS FOR TYING PACKAGES AND WRAPPING MATERIALS the disclosure of which is incorporated herein by reference in its entirety for all purposes However it will be noted that spool 416 of tie material is mounted on a shaft and tie material 15 is fed from spool 14c and is routed around wilers 41b 41 and 41 around needle roller 44 and the end of the ribbon 15 is gripped in the holder shear assembly 60 as best illustrated in FIGS 1 and 14 of the drawing Spool 41c is mounted on a shaft engaged by a brake not shown As needle 42 forms a loop of tie material around the gathered neck of a bag the force of inertia and force exerted by the brake cause the spool 41c to remain stationary momentarily as a crank arm on which roller 41a is mounted is rotated in a clockwise direction as illustrated in FIG 12 of the drawing As will be hereinafter more fully
23. lectric brake being connected to momentarily lock said stop lever in a position extending across said path such that material moving along said slot is gathered adjacent said stop lever 2 Apparatus for securing a bundle of gathered material according to claim 1 with the addition of a source of ribbon a holder shear assembly for cutting the ribbon and grip ping the free end of said ribbon a pulley engaging said ribbon between said source of ribbon and said holder shear assembly a proximity switch adjacent said pulley and a needle engaging said ribbon between said pulley and said holder shear assembly said needle being config ured for wrapping the ribbon around material gathered adjacent said lever said proximity switch being mounted in a circuit configured to indicate when the ribbon has been wrapped around gathered material adjacent said lever 3 Apparatus for securing a bundle of gathered material according to claim 1 said shaft extending through said electric brake such that movement of said stop lever is restrained when said electric brake is energized 4 Apparatus for securing a bundle of gathered material according to claim 3 said timer being electrically connected between said electric brake and said switch for de energizing said electric brake at the expiration of a predetermined period of time after said electric brake has been energized 5 Apparatus for securing a bundle of gathered material according to claim 3
24. n FIG 3 by a spring 83 A switch 86 is actuated by switch arm 88 which actuates a timer for energizing electric brake 82 which momentarily locks bag stop 80 in a fixed position for a predetermined period of time for example 0 25 seconds for restraining the leading edge of a bag neck such that gathering belts 22 and 32 will gather the neck adjacent bag stop 80 At the expiration of the predetermined period of time electric brake 82 will be de energized so that linear movement of the bag neck will rotate bag stop 80 upwardly to release the bag so that it will be moved away by the conveyor Bag stop 80 is biased toward the position illustrated in FIG 3 of the drawing by a spring 83 It should be readily apparent that the spring 83 may be replaced by a counter weight air cylinder or other suitable biasing mechanism to resiliently urge bag stop 80 toward its home position Motors M1 M2 M3 and Md are bi directional perma nent magnet DC brush type servomotors having outputs proportional to the voltage applied across the armatures Such motors are commercially available from Groschopp Inc of Sioux Center Iowa as a Power Master 8304 24 volt DC continuous power motor At 1500 rpm the motor gen erates 16 oz in torque and has an output of 0 090 horsepower at 4 2 amps At 2450 rpm the torque is 47 oz in and the output is 0 113 horsepower at 5 amps At 5400 rpm the torque is 37 oz in and the output is 0 197 horsepower at 8 2 amps It is not
25. n the PWM signal delivered to the terminals marked is not conducting current high rail transistor Q7 and high rail power transistor Q5 are turned on for delivering a positive 34 volt direct current to the motor winding causing motor M2 to tend to move in a clockwise direction When the PWM signal delivered to the terminals marked CH1 are conducting current low rail transistor Q9 and low rail power transistor Q13 are mined on for delivering a negative 34 volt direct current to the motor winding causing motor M2 to tend to move in a counter clockwise direction The ratio of time in which the PWM signal is in either state determines the direction and speed of the motor To protect high rail power transistor Q5 and low rail power transistor Q13 from being conducting at the same time due to differences in manufactured component switch ing times high rail inhibit transistor Q17 disables high rail transistor Q7 from turning on as long as low rail power transistor Q13 is turned on Likewise low rail inhibit transistor Q1 inhibits low rail transistor Q9 from turning on if there is a positive voltage at the collector of high rail power transistor 05 sufficient to forward bias low rail inhibit transistor Q1 The high rail inhibit circuit IH is connected from the collector of the low rail power transistor through diodes D18 and D21 and resistor R29 to the base of high rail inhibit transistor Q17 The emitter of high rail inhibit transistor Q17 i
26. ode combines the best action of proportional control integral control and derivative control in a closed loop control system In addition to the microcontroller chip 96 on the CPU board random access memory RAM integrated circuits 97 are used for storing values in distinct locations which can be recalled or altered for storing the software which controls the system Since the values which are in RAM memory are lost when the power of the computer is turned off a battery backup is provided The microcontroller 96 processes digital signals such as the presence or absence of voltages to represent values The CPU board is connected to an auxiliary board 98 through a connector header which carries data signals and address signals Driver circuits C1 C4 which generate pulse width modulated PWM signals are mounted on the aux iliary board along with the decodes 01 04 The pulse width modulated signals from driver circuits 1 are sent to the motor driven 91 94 selectively delivering positive or nega tive DC power to control the operation of moron 1 Closed Loop The circuits carrying input signals from the encoders RI EA to decoders D1 D4 the circuit carrying pulse width modulated signals from driver circuits C1 C4 to motor driven 91 94 and the circuits carrying per from the motor drivers 91 94 to motors M1 M4 form a closed loop control system The closed loop control system depends upon the 15 35 45 55 10
27. of face plate 16 for driving the needle assembly 40 A motor M3 having an encoder E3 mounted the rear end of motor M3 is mounted vertically on horizontally extending mounting plate 19a for driving the twister hook assembly 50 A motor having an encoder E4 mounted the rear end of motor M4 is mounted on a lower portion of end plate 18 and in the illustrated embodiment extends below motor M2 for driving the holder shear assembly 60 Referring to FIGS 1 5 of the drawing bag neck gather ing apparatus 20 comprises in a preferred embodiment of 10 25 35 45 55 65 4 the invention an upper gathering belt 22 routed around a driven pulley 24 and idler pulleys 26 27 and 28 The bag neck gathering mechanism 20 further comprises a lower gathering belt 32 routed around a driven pulley 34 and idler pulleys 36 37 and 38 As best illustrated in FIG 1 of the drawing the portion 29 of the upper gathering belt 22 extending between idler pulleys 27 and 28 is substantially parallel and closely spaced relative to the portion 39 of the lower gathering belt 32 which extends between driven pulley 34 and idler pulley 36 In the illustrated embodiment gathering belts 22 gand 32 move a bag neck along path 12 in a plane P as illustrated in FIG 2 A pressure pad 21 resiliently urged upwardly by springs 21a and 21b acting through bell cranks maintains belts 22 and 32 in frictional engagement with the neck of a bag or other material to b
28. rawing motor M1 is driven by a solid state DC motor controller 91 which is capable of varying the speed of motor M1 to substantially synchronize movement of upper gathering belt 22 and lowering gathering belt 33 with the speed of a conveyor 300 moving packages 125 adjacent the bag gathering mechanism 20 For example if the tier 10 is to gather and tie the necks of 100 bags per minute the conveyer 300 would preferably bring bags to and through the tier at a speed of approxi mately 300 fect per minute and the gathering belts 22 and 32 would preferably be driven at a speed of for example 305 feet per minute so that the neck of the bag would be accelerated for gathering the neck stopped momentarily while it is being tied with a ribbon and then discharged in a substantially continuous operation As will hereinafter be more fully explained the gathering assembly 26 also includes a bag stop lever 80 illustrated in FIGS 2 and 3 mounted on shaft 85 for rotary movement about a horizontal axis in the illustrated embodiment Shaft 85 extends through an electric brake 82 which momentarily locks lever 80 in a lowered position extending across path 12 such that gathering belts 22 and 32 move the bag neck into engagement with lever 80 After the bag neck has been gathered and tied the electric brake 82 is released and the gathered neck carried between belts 22 and 32 urges lever 80 upwardly such that it does not obstruct movement 5 708 339
29. re employed to designate like parts throughout the various Figures of the drawing DESCRIPTION OF A PREFERRED EMBODIMENT The wire tying device generally designated by the numeral 10 in FIGS 1 and 2 of the drawing is mounted adjacent the side of a conveyor 300 of the type disclosed in Burford U S Pat No 3 138 904 and Burford U S Pat No 3 919 829 the disclosures of which are incorporated herein by reference in their entirety for all purposes Conveyor 300 carries for example loaves 125 of bread to through and out of wire tying device 10 in rapid succession Conveyor 300 is well known to persons skilled in the art and further description thereof is not deemed necessary except in con nection with the drive mechanism as will be hereinafter more fully explained It should be appreciated that other and further structures may form the conveyor Referring to FIG 1 of the drawing the numeral 20 generally designates a bag gathering apparatus for moving a bag 125 along a path 12 to a position adjacent a needle assembly 40 a twister hook assembly 50 and a holder shear assembly 60 As will be hereinafter more fully explained the free end of a ribbon of wire like material 15 is gripped in holder shear assembly 60 The neck of the bag moves 5 708 339 3 through a slot 122 between upper face plate 16 and lower face plate 17 for drawing the bag 125 to a controlled tension about the contents thereof Needle assembly 40 wraps the ribbon 15 o
30. s connected to the base of high rail transistor Q7 The low rail inhibit circuit IL is connected from the collector high rail power transistor Q5 through diodes D7 and D5 and resistor 10 25 35 55 65 12 R3 to the base of low rail inhibit transistor Q1 The emitter of low rail inhibit transistor Q1 is connected to the base of low rail transistor Q9 The low rail and high rail inhibit circuits and IL assure that the control output voltage be zero before switching occurs The inhibit circuits protect the power transistors Q5 and Q13 It is to be understood that while detailed descriptions of a preferred embodiment has been illustrated and described the invention is not to be limited to the specific arrangement of parts and specific features herein described and illustrated in the drawing Rather the descriptions are merely of an exemplary embodiment of the invention which may be embodied in various forms Having described the invention we claim 1 Apparatus for securing a bundle of gathered material comprising a frame having a slot defining a path a shaft secured to said frame a stop lever mounted on said shaft for rotary movement about an axis an electric brake mounted between said stop lever and said frame an electric circuit having a timer connected to said electric brake and a switch in said electric circuit said switch having an arm positioned to extend across said path said switch timer and e
31. said electric motor for gen erating electrical signals related to the position of each said drive shaft a closed loop control circuit connected to said motor and to said encoder and a controller connected to said closed loop control circuit for controlling each of said electric motors to synchro nize movement of each of said assemblies relative to each of the other assemblies 7 Bag neck tying apparatus according to claim 6 with the addition of a proximity switch associated with said source of ribbon and said controller to prevent movement of said holder shear assembly if said needle assembly has failed to wrap the ribbon around a bag neck 8 Bag neck tying apparatus comprising a frame a source of ribbon for dispensing a strand of ribbon having a free end and a central portion electrically driven holder shear assembly for cutting the ribbon and holding the free end of said ribbon a needle assembly for engaging and positioning said central portion of said ribbon adjacent said holder shear assembly a material gathering assembly for gathering material said gathering assembly being positioned adjacent said holder shear assembly atwister assembly movably secured relative to said frame having a hook adjacent said holder shear assembly a switch having an arm positioned to be engaged by material moved by said material gathering assembly a stop lever mounted on said frame an electric brake connected to said switch and to s
32. ssembly 60 comprises a gripper arm 62 having a gripper finger 64 on one end thereof rotatably secured to a mounting plate 66 by bolt 65 A pair of anvils 68 and 69 are formed on the end of mounting plate 66 each being associated with shear surfaces 68a and 69a to grip and cut a strand ribbon as will be hereinafter more fully explained Referring to FIGS 5 and 7 of the drawing cam 70 is mounted on the shaft of motor M4 and is configured to engage cam followers 72 and 74 on spaced am 71 and 73 secured to and actuating rod 75 mounted for reciprocating movement in bearings 76 A link 75a secures the end of gripper arm 62 to actuating rod 75 It should be readily apparent when the shaft of motor M4 rotates one half revolution cam 70 will exert force through cam followers 72 and 74 for moving actuating rod 75 for pivoting the actuating arm 62 about bolt 65 The free end of the ribbon is gripped between the end of gripper finger 64 and anvil 68 or 69 depending on which direction the gripper finger 64 is shifted As will be hereinafter more fully explained when needle 42 wraps the intermediate section of the ribbon 15 around the gathered neck of a bag the ribbon will be positioned between gripper finger 64 and the other anvil 68 or 69 When gripper finger 64 is shifted to its opposite position the ribbon will be cut and the free end of the strand of ribbon will be gripped between gripper finger 64 and anvil 68 or 69 Referring to FIGS 12 and 1
33. tor M1 M2 and respectively The encoders 51 54 are high resolution incremental optical devices which include an encoder body a metal code wheel and emitter end plate An LED source and lenses transmit collimated light from the emitter diode through a precision metal code wheel and phase plate into a bifurcated detector lens not shown The light is focused onto pairs of closely spaced inte grated detectors which output two square wave signals in quadrature and an optional index pulse HEDS 6000 series two and three channel incremental optical encoder kits are available from Hewlett Packard of Palo Alto Calif A standard selection of shaft sizes and resolutions between 192 and 1024 cycles per shaft revolu tion are available The part number for a standard two channel encoder is HDS 6000 while that for the three channel device with index pulse is HEDS 6010 The encoder devices are typically used for printers plotters tape drives positioning tables automatic handlers robots and other servo loop applications Specific details of construc tion of the incremental optical encoder can be found in Hewlett Packard Publication No 5954 8420 3 87 which is incorporated herein by reference The incremental shaft encoder operates by translating the rotation of a shaft into interruptions of a light beam which are then output as electrical pulses The light source is a light emitting diode collimated by a molded lens into a beam of
34. tying apparatus according to claim 8 said source of ribbon comprising ribbon on a spool routed around at least one pulley such that said pulley rotates if ribbon is pulled from said spool a plurality of index pointers on said pulley a proximity switch positioned near said pulley for making an electrical circuit to output pulses when the presence of an indexing pointer is sensed and a CPU connected to said proximity switch to monitor the proximity switch output and count pulses produced by said index pointers said CPU calculating the amount of ribbon dispensed to determine whether or not a bag neck is present as said needle assembly moves toward said holder shear assembly X X UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO 5 708 339 DATED January 13 1998 INVENTOR S Jimmy R Frazier John D Richardson amp Greg P Coxsey It is certified that error appears in the above identified patent and that said Letters Patent is hereby corrected as shown below Column 1 line 18 change Charles C Burford to read Charles E Burford Column 5 line 38 change secured to and to read secured to an Signed and Sealed this Tenth Day of November 1998 Anest on him BRUCE LEHMAN Attesting Officer Commissioner of Patents and Trademarks
35. y such as 115 volt 60 cycle single phase electric ity The energy receiving or secondary circuits of transform ers T1 are connected through one or more rectifier bridge circuits B1 and B2 and capacitors C6 and C7 to a pair of controlled voltage power terminals one of which forms a source of direct current maintained at positive 34 volts and the other a source of direct current at negative 34 volts An eight volt direct current power supply is illustrated in FIG 8 of the drawing The eight volt power supply com prises a pair of terminals connectable to the positive and negative 34 volt terminals of power supply 90 through resistors R13 and R24 to positive and negative 8 volt terminals A pair of diodes Zenier 015 and D20 are provided in the 8 volt power supply between resistors R13 and R24 and a ground terminal The rectifiers in bridge circuits B1 and B2 are conven tional MB 352 rectifiers Capacitors C6 and C7 are for example 33 000 UF capacitors Resistors R13 and R24 are 470 ohm 2 watt resistors The 34 volt and 8 volt power supplies illustrated in FIGS 7 and 8 are of conventional design and form no part of the present invention except in combination with the other elements of the control circuit It should be appreciated that many other DC power supplies may be used in lieu of those illustrated in the drawing Encoders Conventional multichannel incremental optical encoders E1 E2 and E4 are mounted on the shaft of each mo
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