US3636543A - Safety limit feeler for contactless control - Google Patents

Safety limit feeler for contactless control Download PDF

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Publication number
US3636543A
US3636543A US862897A US3636543DA US3636543A US 3636543 A US3636543 A US 3636543A US 862897 A US862897 A US 862897A US 3636543D A US3636543D A US 3636543DA US 3636543 A US3636543 A US 3636543A
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United States
Prior art keywords
control
slot
arrangement according
magnetic
amplifier
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
Application number
US862897A
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English (en)
Inventor
Kurt Maecker
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Individual
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Individual
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Publication of US3636543A publication Critical patent/US3636543A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/95—Proximity switches using a magnetic detector
    • H03K17/952—Proximity switches using a magnetic detector using inductive coils
    • H03K17/9537—Proximity switches using a magnetic detector using inductive coils in a resonant circuit
    • H03K17/9542—Proximity switches using a magnetic detector using inductive coils in a resonant circuit forming part of an oscillator
    • H03K17/9547—Proximity switches using a magnetic detector using inductive coils in a resonant circuit forming part of an oscillator with variable amplitude
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/95—Proximity switches using a magnetic detector
    • H03K17/9502—Measures for increasing reliability
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/95—Proximity switches using a magnetic detector
    • H03K17/9505—Constructional details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/95—Proximity switches using a magnetic detector
    • H03K17/9517—Proximity switches using a magnetic detector using galvanomagnetic devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/965—Switches controlled by moving an element forming part of the switch
    • H03K17/97—Switches controlled by moving an element forming part of the switch using a magnetic movable element

Definitions

  • the present invention relates to a safety limit feeler which is actuated without being contacted.
  • Limit feelers of this type are known, and two groups of limit feelers are to be differentiated in this connection.
  • the devices are actuated by a permanent magnet or cam which is passed by the device.
  • the magnetic effect may, inductively, through the intervention of a coil or by varying the resistance of a semiconductor (Hall generator, field plates); initiate a circuit or switching operation.
  • a Reed contact may also be affected magnetically.
  • the second group of contactless actuated devices operates with electronic oscillating circuits (initiators) while in view of the damping of the outwardly extending lines of flux, a change in the resistance is effected through some metal part whereby a circuit or a switching operation is initiated.
  • the release part such as a cam may in this instance consist of ordinary metal so that no metal dust will collect and be held
  • these switches are, in contrast to the first group, particularly well suitable in general machine construction and especially for machine tool controls. This is the case all the more inasmuch as they may simultaneously have very narrow tolerances as to repeat performance depending on the design and spacing up to 0.01 millimeters.
  • Both groups have, however, the drawback that in particular with fully electronic circuit they do not permit any outward control concerning their functions.
  • a transistor effects a control operation or brings about a switching operation which means that without outer entrance signal, an output signal is released which acts upon the device or apparatus as if it has been deliberately actuated.
  • the oscillating circuit is actuated by any foreign metal part or, on its own, also without outer influence, changes its characteristic.
  • FIG. 1 diagrammatically illustrates a top view of an ordinary limit switch for a machine tool for which the arrangement according to the present invention may be used.
  • FIG. 2 shows a view of the head of the switch according to FIG. 1 into which head the safety device according to the invention has been built.
  • FIG. 3 is an electric diagram of the arrangement according to the invention.
  • FIG. 4 illustrates a modified circuit according to the invention.
  • FIG. 5 illustrates a particular design of the safety system according to the invention in the limit switch of a machine tool.
  • FIG. 6 illustrates another embodiment of the safety system in the limit switch of a machine tool as seen from the side.
  • FIG. 7 is an end view of the switch according to FIG. 6.
  • FIG. 8 is a top view of the switch according to FIG. 6.
  • the above object has been realized according to the present invention by having two control systems which, through an amplifier, for instance in the form of a transistor, thyristor-amplifier or the like, act upon a relay or a corresponding device which so controls the arrangement and are so arranged and adjusted that both have to be actuated within a predetermined set time, or if this does not occur, and alarm signal is given off through the intervention of a further amplifier.
  • an amplifier for instance in the form of a transistor, thyristor-amplifier or the like
  • the entrance circuits will, to the exit transistors, convey a further input of the two control systems to the disturbance transistor through the intervention of an and and or" as well as through the reversal and through time elements.
  • the entrance control circuits of the control system may be formed by oscillating circuits or magnetic field dependent semiconductors or by resistors or also magnetically influenced Reed contacts.
  • the cam i.e., the initiating element
  • the cam will cooperate with a coulisse which is built up on the head 2 of the switch.
  • the cam would cooperate with the coulisse in such a way and may be so designed that when being actuated the cam will move itself between the coulisse and the control surface whereby the control surface is actuated and, as the case may be, is simultaneously covered.
  • the coulisse arranged at the head of the switch may be so designed that it forms a coulisse chamber in which the control surface is arranged.
  • the cam or the initiating part may form a U-shaped yoke one arm of which moves itself through an opening in the coulisse while actuating the control surface, whereas the other arm is connected to the movable initiating part.
  • the coulisse chamber is so narrow that the chips and the dust in cooperation with the passage of the initiating part will not remain deposited in a disturbing manner.
  • FIG. I shows a limit switch for a machine tool which is provided with a control head 2.
  • the said control head has built thereinto the control systems according to the invention, in this particular instance, two oscillating circuits 3.1 and 3.2. These two oscillating circuits are, by means of the metallic part 4.1, controlled in one and/or 4.2 in the other direction.
  • the control system is more clearly shown in FIGS. 3 and 4.
  • two electronic oscillating circuits 3.1 and 3.2 are provided which act upon the transistor amplifier 6.1 which then in its turn through a relay or a corresponding element effects the control.
  • the two oscillating circuits are furthermore provided with a trouble amplifier 13 which emanates the trouble or alarm signals.
  • FIG. 3 shows the condition in which the oscillating circuits are not dampened.
  • Both oscillating circuits 3.1 and 3.2 convey their outputs A.1 and A.3 directly to the entrance of the transistor amplifier 6.1.
  • the two other outputs A2 and A.4 are through the intervention of an or" member 5' conveyed to the second entrance E2 of the transistor or tyristor-amplifier 6.1.
  • the outputs A2 and AA are furthermore simultaneously through the reversing members 7 and 9 conveyed to the and" members 8 and 10.
  • the fand members 8 and 10 at their entrance are in the position 0.l. Thus, they cannot effect a further control movement.
  • the oscillating circuit 3.1 would be dampened, in other words, if A.2 would change the value of its resistance for instance from a high value output A.2O to a low value output A.2-L, the output A.2 would shift to L. In such an instance, at 7 the reversal from L to would be effected, the and member 8 would have 0 and O at its entrance sides and would not exert a further control action. A.2 will also directly convey to the and member 10. And" member 10 would now have two inputs L and would therefore shift its output likewise to L and through the or member 11 and time member t would control the amplifier 13 which produces a trouble or alarm signal.
  • the second oscillating circuit 3.2 were likewise dampened, also the output AA would come to the position L.
  • the and member 10 would have the inputs 0 and L.
  • the and" member 10 would thus not exert a control action.
  • the and" member 8 will at the entrance show 0 and L. This practically means that also with the very low strokes, for instance, at 6 millimeters per minute 0.06 millimeters per second, and with possible tolerances in the spacial arrangement of the two oscillating circuits, no trouble or alarm signal would be given.
  • the time relay has to be adjusted for this distance and the lowest answering speed.
  • FIG. 4 shows the same arrangement as FIG. 3 but according to FIG. 4 there is additionally checked the control of the transistor 6.]. If none of the two oscillating circuits is controlled, but nevertheless due to an interior trouble, for instance caused by the network voltage, the exit transistor 6.1 is controlled or connected through, in view of the and member 14 which at both reversing members 7 and 9 receives the entrance L, also the third entrance from exit 0.1 of the amplifier 6.1 would get an L and thus would likewise make the amplifier 13 effective. The entrance circuits of the two control systems will be bypassed.
  • slot-initiators 5.1 and 5.2 may be employed which must be actuated by a specifically shaped metallic member 6 which in the particular instance shown has the shape of a structural T-member.
  • the limit feeler comprises a housing 1 with the conductor inlet 20.
  • the housing 1 has a head 2 with built-in electric oscillating circuit.
  • the said head 2 is provided with the control surface or active surface 21 which is located in a coulisse chamber 22 formed by the coulisse 25/24.
  • the coulisse chamber 22 has an opening 22a through which the initiating member 25 extends into the coulisse chamber 22.
  • the member 25 is mounted on the movable cam 26 which is clamped into a groove of the groove field 27.
  • FIG. 7 shows the control surface 21 as seen from the front and how it is located on the head 2.
  • FIG. 8 illustrates the control device of FIG. 6 as seen from the top while, for instance, the groove field moves horizontally on a milling machine table. According to FIG. 6, the groove field may also move perpendicularly with regard to the plane of the drawing.
  • a double safety of the function of the device is assured because the control of one input circuit suffices to effect an operational control through the transistor 6.1.
  • the safety consists in that the nonfunctioning of an input circuit, regardless for what reason, will energize a special trouble circuit which will draw the attention of the operator to the fact that somewhere some trouble occurred.
  • the trouble circuit according to the invention may also be used directly for stopping the machine. Additionally, the checking of the operation of the amplifier 6.1 is assured.
  • a relay energizable to effect a control function
  • a first amplifier having output terminal means connected to said relay to supply energy thereto, said first amplifier having input terminal means sensitive to a signal for causing said output tenninal means to supply energy to said relay
  • a pair of control elements having output terminals and sensitive to the movement of an actuating member in the region thereof for developing signals at said output terminals
  • an OR gate connecting said output terminals to said input terminal means of said amplifier, whereby a signal at the output terminal of either of said control elements will cause said first amplifier to supply energy to said relay
  • an alarm circuit including a second amplifier having input terminal means and operable to actuate said alann circuit upon the supply of a signal to said input terminal means thereof, and means connecting the output terminals of said control elements to the input terminal means of said second amplifier and operable in the absence of a signal from the output terminals of one of said control elements and the presence of a signal from the output terminal of the other of said control elements for supplying a signal to the
  • each control element is in the form of an oscillating circuit having a magnetic control portion, a body housing said control elements, said portions being located in side-by-side relation in an end part of said body, said actuating member comprising a magnetic member adapted for influencing both of said magnetic control portions simultaneously when brought into proximity thereto from either direction.
  • a control arrangement in which said one end of said body is formed with a -shaped slot and said magnetic member is T"-shaped and is moveable in said slot.
  • a control arrangement in which said one end of said body comprises an arm arranged in with a machine part.

Landscapes

  • Auxiliary Devices For Machine Tools (AREA)
  • Electronic Switches (AREA)
  • Numerical Control (AREA)
US862897A 1968-11-15 1969-10-01 Safety limit feeler for contactless control Expired - Lifetime US3636543A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681809100 DE1809100B2 (de) 1968-11-15 1968-11-15 Sicherheitgrenztaster fuer beruehrungsloses schalten

Publications (1)

Publication Number Publication Date
US3636543A true US3636543A (en) 1972-01-18

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Application Number Title Priority Date Filing Date
US862897A Expired - Lifetime US3636543A (en) 1968-11-15 1969-10-01 Safety limit feeler for contactless control

Country Status (4)

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US (1) US3636543A (de)
CH (1) CH532833A (de)
DE (1) DE1809100B2 (de)
GB (1) GB1282038A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0027049A1 (de) * 1979-10-08 1981-04-15 Duraplug Electricals Limited Elektrische Schalter
US4339749A (en) * 1979-07-03 1982-07-13 Toyo Tokushu Kiki Co., Ltd. Abnormal condition sensing monitor system for use with machine tools
EP0219017A1 (de) * 1985-10-07 1987-04-22 Maschinenfabrik Rieter Ag Positioniersysteme
US4977984A (en) * 1988-08-23 1990-12-18 Inventio Apparatus and method for detecting elevator car position in a door zone
EP0374962A3 (de) * 1988-12-22 1991-01-09 Kci-Kone Cranes International Oy Druckknopfgehäuse
EP0360263A3 (de) * 1988-09-22 1991-05-02 Omron Tateisi Electronics Co. Sich selbst prüfender Näherungsschalter
EP0758708A1 (de) * 1995-08-11 1997-02-19 Grupo Antolin-Ingenieria, S.A. Einklemmschutz
US6114690A (en) * 1998-01-23 2000-09-05 Penn Engineering & Manufacturing Corp. Light-controlled safety switch for a punch press

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3220111C1 (de) * 1982-05-28 1983-06-09 Honeywell Gmbh, 6050 Offenbach Überwachungseinrichtung für Näherungsschalter
CH668872A5 (de) * 1985-07-05 1989-01-31 Baumer Electric Ag Naeherungsschalter.
AU5420790A (en) * 1989-04-14 1990-11-16 Eja Engineering Company Limited Safety switch assembly

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4339749A (en) * 1979-07-03 1982-07-13 Toyo Tokushu Kiki Co., Ltd. Abnormal condition sensing monitor system for use with machine tools
EP0027049A1 (de) * 1979-10-08 1981-04-15 Duraplug Electricals Limited Elektrische Schalter
EP0219017A1 (de) * 1985-10-07 1987-04-22 Maschinenfabrik Rieter Ag Positioniersysteme
EP0522598A3 (en) * 1985-10-07 1993-03-10 Maschinenfabrik Rieter Ag Locating systems
US4977984A (en) * 1988-08-23 1990-12-18 Inventio Apparatus and method for detecting elevator car position in a door zone
EP0360263A3 (de) * 1988-09-22 1991-05-02 Omron Tateisi Electronics Co. Sich selbst prüfender Näherungsschalter
EP0374962A3 (de) * 1988-12-22 1991-01-09 Kci-Kone Cranes International Oy Druckknopfgehäuse
EP0758708A1 (de) * 1995-08-11 1997-02-19 Grupo Antolin-Ingenieria, S.A. Einklemmschutz
ES2124144A1 (es) * 1995-08-11 1999-01-16 Irausa Ing Sa Dispositivo antipinzamiento.
US6114690A (en) * 1998-01-23 2000-09-05 Penn Engineering & Manufacturing Corp. Light-controlled safety switch for a punch press

Also Published As

Publication number Publication date
CH532833A (de) 1973-01-15
DE1809100A1 (de) 1970-07-23
DE1809100B2 (de) 1971-09-02
GB1282038A (en) 1972-07-19

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