US2821670A - Electronic controls for cutting machines - Google Patents

Electronic controls for cutting machines Download PDF

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Publication number
US2821670A
US2821670A US48755355A US2821670A US 2821670 A US2821670 A US 2821670A US 48755355 A US48755355 A US 48755355A US 2821670 A US2821670 A US 2821670A
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US
United States
Prior art keywords
relay
platen
voltage
resistor
die
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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English (en)
Inventor
Robert W Bradley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
United Shoe Machinery Corp
Original Assignee
United Shoe Machinery Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB276855A priority Critical patent/GB764634A/en
Application filed by United Shoe Machinery Corp filed Critical United Shoe Machinery Corp
Priority to US48755355 priority patent/US2821670A/en
Priority to DEU3673A priority patent/DE1033763B/de
Priority to DK9356A priority patent/DK109608C/da
Priority to ES0226750A priority patent/ES226750A1/es
Application granted granted Critical
Publication of US2821670A publication Critical patent/US2821670A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D33/00—Accessories for shearing machines or shearing devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
    • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
    • B26D7/20—Cutting beds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
    • C—CHEMISTRY; METALLURGY
    • C14—SKINS; HIDES; PELTS; LEATHER
    • C14B—MECHANICAL TREATMENT OR PROCESSING OF SKINS, HIDES OR LEATHER IN GENERAL; PELT-SHEARING MACHINES; INTESTINE-SPLITTING MACHINES
    • C14B5/00—Clicking, perforating, or cutting leather
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F2210/00—Perforating, punching, cutting-out, stamping-out, severing by means other than cutting of specific products
    • B26F2210/12—Perforating, punching, cutting-out, stamping-out, severing by means other than cutting of specific products of fabrics
    • B26F2210/16—Perforating, punching, cutting-out, stamping-out, severing by means other than cutting of specific products of fabrics the cutting machine comprising a cutting die
    • C—CHEMISTRY; METALLURGY
    • C14—SKINS; HIDES; PELTS; LEATHER
    • C14B—MECHANICAL TREATMENT OR PROCESSING OF SKINS, HIDES OR LEATHER IN GENERAL; PELT-SHEARING MACHINES; INTESTINE-SPLITTING MACHINES
    • C14B2700/00—Mechanical treatment or processing of skins, hides or leather in general; Pelt-shearing machines; Making driving belts; Machines for splitting intestines
    • C14B2700/11—Machines or apparatus for cutting or milling leather or hides
    • C14B2700/113—Cutting presses
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8691—Unicyclic
    • Y10T83/8693—With adjustable stopping point or tool

Definitions

  • the cutting support usually comprises a block of wood or a pad of rubber or other material which is rigid enough to support the sheet material against pressure applied by the platen,
  • Patent No. 2,788,070 discloses an improved organization of a cuttingpress in which there is a work support and a platen each embodying a conductive member, the platen being arranged for movement toward and away from the support to engage a die and press it through a work piece on the support, power means for moving the platen, stroke initiating means operable to cause the power means to initiate movement of the platen toward the support, and stroke terminating control means responsive to the formation of an electrical conductance path from the platen member through the die to the support member, to cause said power means to terminate the movement of the platen toward the support.
  • the operation of the stroke terminating control of the organization depends upon direct connection of a power source to a relay switch through the aforesaid path so that the path must carry the relay current
  • the first contact of the die with the support may not suffice to close the relay, particularly if the conductive material of the support is conductive rubber.
  • the relay response may not be uniformly time related to such first contact but may occur at different stages of die penetration of the work or support, to the detriment of the organization performance.
  • an object of the present invention to provide for use in such an organization an improved stroke terminating control having a response which is uniformly time related to a reference condition of a cut, for example, to the first contact between the die and the support even if the resistance of the latter has an appreciable magnitude.
  • Yet another object of the present invention is to provide such a control having improved fail-safe features.
  • a two-stage safety stroke terminating control employing a relay circuit having a D. C. input stage comprising an electron tube preferably, and as illustrated, a grid-controlled gaseous discharge tube and a normally conducting grid-controlled full-wave A. C. rectifier output stage arranged to be cut 05 upon initiation of a discharge through an input tube to effect relay operation a predetermined time after such initiation.
  • This arrangement prevents initiation of the cutting stroke unless the emission of the output tubes is adequate.
  • the input tube is biased normally non-conductive while means, including connections to the platen and support member, are provided in the grid circuit to change the bias at first contact of the die to. fire the tube.
  • the initial cut-ofi bias is provided by a source of direct voltage including substantial efiective series resistance.
  • the source is connected across the input electrodes of the tube and across the conductive members of the work support and'platen so that the intermember resistance, which thus loads the source, forms with said series source resistance a voltage divider, where by the effective bias voltage is proportional to the intermember resistance and a reduction thereof below a predetermined value is effective to reduce the bias voltage to the critical level at which the tube becomes conductive, even though the resistance of the path, including the connections, from one member to the other,'has an appreciable magnitude.
  • Manually operable stroke initiating means for controlling the fiuid-operated motor to initiate a downward stroke of the platen 18 comprises a switchmechanism 42 having an operating handle-3'44 disposed at the front of the platen. in the illustrated position of a switch S2, downward movement of the handle 44 is effective to connect one line 46 of the A. C. supply lines 46, 43 to an intermediate conductor 50, while in the other position of the resistance between the connecting points of the members 7 under difierent die-engaging conditions.
  • a variable time constant circuit is connected in the output circuit ofsaid input stage,- so'that the outputof saidvariable time constant circuit, and consequently its delay function, is isolated by the D. C. input stage from variation with variation of the resistance between "the connections tothe-membe'rs.
  • the use of D. C. plate voltage in the inputstag'e further avoids introducing variations due to the cyclic condition of the alternating-current source.
  • Fig. 1 is a diagrammatic representationof apparatus embodying-the presentinvention.
  • Fig. 2 is a schematic of a modified embodiment of said invention.
  • the cutting press organization illustrated therein comprises a work support 10 including a conductive work-support'member 12, which may consist of conductive rubber, for supporting work pieces 14 of sheet material, such as leather, fabric or the like to be operated upon by "a freelymovable die 16 to produce blanks.
  • a platen or beam 18, including a metallic striking plate 19 providing a conductive platen member, is mounted upon a vertical post 29 at one side of the support 10 for swinging-movement across it, the platen being arranged for reciprocation toward and away from [the support to force the die 16 through the work piece.
  • the plate 19 is insulated from the rest of the platen as disclosed in United S tates Letters Patent No. 2,783,838, granted March 5, i957 inthe names-of Roy G. Ericson and Frank E. Stratton.
  • Power'm'ea'n's for reciprocatingvthe platen 18 are "preferably'fluid operated and'are'illustrated as comprising a piston 22 connected tothe lower end ofthe post and slidably mounted ina'cylinder 24, the cylinder and the piston providing a fluid-operated motor.
  • Control'of-the fluid-operated motor is provided by a valve 26-havingan axially movable valveelement 28.
  • a valve-element 28 When the valve-element 28 is in its upper position as shown, a lowerport 30 inthe cylinder '24 is connected-to a supply pipe 32 and-an upper port '34-is connected to an exhaust'pipe 36so that the piston 22 is urged upwardly.
  • the valveelement' 28 When the valveelement' 28 is in its lowermost position, the connections-to the ports are reversed so that the piston is urged downwardly.
  • switch S2 in order to accomplish this connection, not only must the handle 44 be moved downwardly but also a second button 51 on the side of the platen must be depressed, thus requiring both hands of the operator to be above the striking plate 19.when initiatinga cutting stroke.
  • a starting relay '52 has three normally open sets of contacts, one set,'52a being included in a self-holding circuit for the relay, a second set, 52b, being included in the energizing circuit for the solenoid 40, and the third set 52c, being included in the plate voltage supply circuit of an electronic stroke terminating control.
  • This control hereinafter described in detail, includes a relay 54 having two sets of normally closed contacts 54a and 54b in'series respectively with the contacts 52a and 52b.
  • An auxiliary relay 56 has three sets of contacts, a normallyopen set 56a'connected between the relay coil and the conductor 50, a normally closed set 56b series-connected in the energizing circuit for the solenoid 40, and a normally closed set 56c series connectedin the energizing circuit for the coil of the relay 52.
  • the coil of relay 56 i's' connected'forenergization upon actuation of a pressure switch 57 or,if a switch S1 is closed, of a limit switch 58, a's'ftirther'disclosed andclaimed in the aforesaid Stratton and MacKenzie application.
  • Energization of the conductor 50 as aforesaid is eifec- 'tive to energize the relay 52 through the set of contacts "56c; contact'set 52a closes to complete a holding circuit including contacts 560, set 52b closes to energize the solenoid 40 to initiate the cutting stroke, and set 52c closes to supply plate voltage to the stroke terminating control.
  • the stroke terminating control comprises two thyratrons:60,'62 connected in a two stage relay circuit.
  • the thyratron 60 has input electrodes comprising a control 'grid' 64 and acathode-66. Across the input electrodes is connected an input'circuit comprising a source of direct "currentbias voltage providing substantial effective series resistance, illustrated as a battery 68 in series with a resistor 70, and "a grid current limiting resistor 72.
  • the battery 68 and the resistor 70 are herein considered together as comprisinga source of D. C. bias including substantially effective series resistance although a source having 'equivalent'internal resistancemay be used without a separate resistor.
  • a smoothing condenser 74 is connected across the input electrodes.
  • the source of bias voltage' is connected across the conductive members 19 and'12-of'the platen and support by leads 73 and 75 respectively.
  • any conductance connected across thebias source as 'a load will operate with its internal resistance, that -is, with the resistor 70, as a voltage divider to redueethe bias voltage on thecontrol grid 64, and that the parameters' o'f the bias source may be adjusted to cause the thyratron 60 to fire at any givenvalue of the shunt conductance, which may conveniently be about 5003000ohms. Thisvalue is suflicient to insure prompt firing of-thethyratrontoreturn the platen should a portioxrof'the' operators hand be caught between the platen and the work support.
  • Firing of the thyra'tron' 60 produces a voltage across a cathode resistor 76 which voltage is 'applied through -aresistor 38 0f an RC 'timeconstant circuit to initiate the charging of avariable capacitance element 80, which as shown may comprise a bank of condensers and. a selector switch.
  • a variable capacitance element 80 which as shown may comprise a bank of condensers and. a selector switch.
  • the voltage at the control electrode 82 of the thyratron 62 rises sutficiently to overcome the negative bias provided in its input circuit by a resistor 84 (connected across the plate voltage supply in series with a resistor 86), thereby firing the thyratron 62.
  • the thyratron 62 has in its output circuit, in addition to the D. C. source, the coil of the relay 54 which upon energization operates through its upper contacts 54a to break the aforesaid holding circuit to the intermediate conductor 50 and through its lower contacts 54b to break the circuit to the solenoid 40. Accordingly, it will be seen that the solenoid 40 is then deenergized whether the switch 42 is open or closed so that the valve element 28 moves to its upper position to terminate the cutting stroke of the platen and to cause it to be moved upwardly to its rest position.
  • the relay 54 receives substantially the full plate voltage, a voltage which is preferably more than sufficient to bring in its armature.
  • the initial voltage on the relay may be made considerably higher than its normal operating voltage, to bring in the armature very rapidly without endangering the relay by the imposition of a sustained overcurrent.
  • such mechanical characteristics of the relay as starting friction and the like which may be variable through the life of the relay, will have minimum deleterious effect upon the timing provided by the control.
  • Component Description Tubes 60 and 62 2D2l. Resistor 70 6.8 M.
  • Resistor 78 3.9 M.
  • Resistor 86 1.8 K.
  • Resistor 84 5.6 K.
  • the striking plate 19 comes into contact with the die 16 and presses it through the Work piece.
  • the resistance of the conductance path from the lead 73 through the striking plate, the die 16 and the support member 12 to the lead 75 decreases rapidly, and when it drops below the value required to sustain a nonconductive bias on the thyratron 60, the latter will be fired.
  • substantially the entire B+ voltage will appear at the cathode of this thyratron and the capacitance element 80 will commence to charge through the resistor 78.
  • Fig. 2 illustrates an embodiment of the present invention in a two-stage relay circuit in which the input stage is similar to that disclosed in Fig. 1, thus comprising a thyratron having a control grid 102 connected to a source 104 of negative bias voltage comprising a resistor 106.
  • the bias source is connected across the striking plate 19 and the work support member 12' in the same manner as in Fig. 1.
  • the output stage of the control comprises two thyratrons and 112 arranged in a fullwave rectifier circuit in which current normally flows from the ends of the secondary 114 of a transformer 116 alternately through the thyratrons 110 and 112 to their interconnected cathodes and thence through the coil of a relay 118 to a center tap on the secondary 114.
  • the thyratrons 110 and 112 are normally conductive by reason of the connection of their control grids 120 and 122 to the cathodes through grid current limiting resistors 124 and 126 and a resistor 128 connected between the cathodes and the junction of the resistors 124 and 126.
  • the output circuit of the thyratron 100 may be traced from a source of plate voltage comprising a rectifier connected to one of the supply lines 46 through contacts 132a of a relay 132, through the tube 100 to its cathode, and through a cathode resistor 134 to a lead 136 and back to the supply line 48.
  • the cathode resistor 134 is connected to a time constant circuit comprising a resistor 138 and a variable condenser 140 in such a manner that, when the thyratron 100 is conducting, the voltage drop across the cathode resistor 134 is applied to charge the condenser 140 through the resistor 138 so that the upper plate of the condenser which is connected to the grids of the tubes 110 and 112 is charged negative with respect to the lower plate which is connected to the cathodes of the said tubes. Accordingly, it will be seen that firing of the thyratron 100 operates to cut ofi conduction by the tubes 110 and 112 after an interval determined by the setting of the condenser 140.
  • the cutting stroke is initiated by closure of a hand switch 42 to connect the coil of the relay 132 across the lines 46' and 48.
  • the resultant energization of the relay 132 closes the contacts 132a and 132b respectively to supply plate voltage to the anode of the thyratron 100 and to connect the cathodes of the thyratrons 110 and 112 to the relay 118. If the latter thyratrons are working properly, the relay 118 will then be energized to connect the solenoid 40' across the supply lines 46 and 48' and to complete a holding circuit for the relay 132 around the switch 42.
  • the latter circuits are subject to being broken by energization of an auxiliary relay 54 in response to the closure of a pressure switch 56 in the event of excessive fluid pressure forming in the fluid system.
  • the operator positions the work and die as before described and presses the starting switch 42' to initiate the cutting stroke.
  • the condenser 140 commences to charge until the grids 120, 122 are sufficiently negative with respect to the cathodes to prevent one of the thyratrons 110 and 112 from passing further current.
  • the inductance of the coil of the relay 118 tends to keep current flowing through the other (the last one of the thyratrons 110, 112 which was conducting).
  • Electrical timing apparatus comprising, in combination, a first gaseous ,dischargetube having an anode, a cathode and a control-electrode, an input vcircuit for said tube including'a source of DC. bias voltage effective to maintainsaid tube-normally nonconductive, said biassource including substantial effective series resistance whereby the, bias voltage "may be'reduced to thecritical value by a conductance path of moderate resistance shunted across the source, an output circuit for said tube comprising a D. C. source and a series resistor, a time constant circuit comprising a resistor element anda capacitance element connected in. series' .across'..said "resistor whereby said capacitance element is arrangedfor charging.
  • :tw-o' thyratrons connectedtin a fullwave rectifier .stage, the cathodes and the control grids of said. :thyratrons being connected for negative "biasing by the voltage across said? capacitance elemen't, .a trans former havinga center-tapped secondary, and a relay having :its'coil-connected in series between-the cathodes ofcsaid thyratrons in the center-tap of said secondary, saidprelay .beingthereby arranged normally to beenen gized and tube deenergizjed in response to the initiation of discharge through said discharge tube after an interval determinedbysaid timeconstanttcircuit.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Forests & Forestry (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Looms (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Punching Or Piercing (AREA)
US48755355 1955-01-13 1955-02-11 Electronic controls for cutting machines Expired - Lifetime US2821670A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB276855A GB764634A (en) 1955-02-11 1955-01-31 Improvements in or relating to presses suitable for use in performing cutting operations on sheet materials
US48755355 US2821670A (en) 1955-02-11 1955-02-11 Electronic controls for cutting machines
DEU3673A DE1033763B (de) 1955-02-11 1955-12-30 Selbsttaetige elektrische Steuerschaltung fuer Pressen, Stanzen od. dgl.
DK9356A DK109608C (da) 1955-01-13 1956-01-11 Stansemaskine, perforeringsmaskine eller lignende maskine.
ES0226750A ES226750A1 (es) 1955-02-11 1956-02-10 UNA MáQUINA PARA CORTAR, PERFORAR O EJECUTAR OPERACIONES ANáLOGAS

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US48755355 US2821670A (en) 1955-02-11 1955-02-11 Electronic controls for cutting machines

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Publication Number Publication Date
US2821670A true US2821670A (en) 1958-01-28

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US48755355 Expired - Lifetime US2821670A (en) 1955-01-13 1955-02-11 Electronic controls for cutting machines

Country Status (4)

Country Link
US (1) US2821670A (de)
DE (1) DE1033763B (de)
ES (1) ES226750A1 (de)
GB (1) GB764634A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011101A (en) * 1957-11-04 1961-11-28 Sr Francis Merritt Boyce Phototube control circuit
US3474695A (en) * 1967-06-13 1969-10-28 Usm Corp Control for cutting presses
US4534249A (en) * 1981-06-06 1985-08-13 Usm Corporation Stroke control for press

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1264679B (de) * 1959-01-15 1968-03-28 United Shoe Machinery Corp Schwenkarmstanze
DK119471B (da) * 1962-10-10 1971-01-11 Pedersen V As Stansemaskine med elektrisk styring af stansearmens nederste stilling.
CN111941505B (zh) * 2020-07-30 2022-08-02 苏州世沃电子科技有限公司 一种可去除刀印的绝缘片加工装置

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1901663A (en) * 1931-04-17 1933-03-14 Westinghouse Electric & Mfg Co Control system
US2052273A (en) * 1935-07-20 1936-08-25 Bell Telephone Labor Inc Remote control circuit
US2095742A (en) * 1934-08-15 1937-10-12 Westinghouse Electric & Mfg Co Constant voltage rectifier
US2203468A (en) * 1938-02-12 1940-06-04 Rca Corp Regulator for time delay circuits
US2409522A (en) * 1944-03-31 1946-10-15 Rca Corp Gas tube circuit
US2426287A (en) * 1945-09-08 1947-08-26 United Shoe Machinery Corp Dieing-out machine
US2442578A (en) * 1946-12-27 1948-06-01 Cutler Hammer Inc Timing system
US2462326A (en) * 1946-09-09 1949-02-22 Crompton & Knowles Loom Works Electric weft detector for looms
US2463318A (en) * 1944-08-05 1949-03-01 Gen Electric Electronic time delay circuit
US2550462A (en) * 1946-01-16 1951-04-24 Gen Electric Rectifier regulator

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1901663A (en) * 1931-04-17 1933-03-14 Westinghouse Electric & Mfg Co Control system
US2095742A (en) * 1934-08-15 1937-10-12 Westinghouse Electric & Mfg Co Constant voltage rectifier
US2052273A (en) * 1935-07-20 1936-08-25 Bell Telephone Labor Inc Remote control circuit
US2203468A (en) * 1938-02-12 1940-06-04 Rca Corp Regulator for time delay circuits
US2409522A (en) * 1944-03-31 1946-10-15 Rca Corp Gas tube circuit
US2463318A (en) * 1944-08-05 1949-03-01 Gen Electric Electronic time delay circuit
US2426287A (en) * 1945-09-08 1947-08-26 United Shoe Machinery Corp Dieing-out machine
US2550462A (en) * 1946-01-16 1951-04-24 Gen Electric Rectifier regulator
US2462326A (en) * 1946-09-09 1949-02-22 Crompton & Knowles Loom Works Electric weft detector for looms
US2442578A (en) * 1946-12-27 1948-06-01 Cutler Hammer Inc Timing system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011101A (en) * 1957-11-04 1961-11-28 Sr Francis Merritt Boyce Phototube control circuit
US3474695A (en) * 1967-06-13 1969-10-28 Usm Corp Control for cutting presses
US4534249A (en) * 1981-06-06 1985-08-13 Usm Corporation Stroke control for press

Also Published As

Publication number Publication date
GB764634A (en) 1956-12-28
ES226750A1 (es) 1956-04-16
DE1033763B (de) 1958-07-10

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