US3590270A - Sensing switch - Google Patents

Sensing switch Download PDF

Info

Publication number
US3590270A
US3590270A US3590270DA US3590270A US 3590270 A US3590270 A US 3590270A US 3590270D A US3590270D A US 3590270DA US 3590270 A US3590270 A US 3590270A
Authority
US
United States
Prior art keywords
feedplate
strip
paper
ball
sensing switch
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
Other languages
English (en)
Inventor
Guy Weber
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.)
Cellophane SA France
Original Assignee
Cellophane SA France
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
Application filed by Cellophane SA France filed Critical Cellophane SA France
Application granted granted Critical
Publication of US3590270A publication Critical patent/US3590270A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/16—Contacts characterised by the manner in which co-operating contacts engage by abutting by rolling; by wrapping; Roller or ball contacts

Definitions

  • roller element journaled in a spring arm and biased against a contact plate by the action of the spring arm.
  • the spring arm and contact plate are in the loop of an electrical circuit which actuates further switching operations.
  • the electrical circuitry includes a transistor and when the switch is open, current is caused to flow from the base to the emitter of the transistor thus causing current to flow from the collector to the emitter of the transistor which operates to switch a large load in the circuitry ofthe transistor.
  • FIG 5 E I Guy WERE R SENSING SWITCH BACKGROUND OF THE INVENTION
  • Known sensing switches generally operate abruptly, that is to say, a slight mechanical pressure immediately causes the change in equilibrium of a strip or spring, causing the desired making or breaking of current.
  • these devices of which the contact pressure is relatively low, have to serve to control relatively large currents, it is generally necessary to use a relay as an intermediate device.
  • sensing switches used in duplicating machines must be disengaged by an extremely gentle contact. These devices must be particularly sensitive while remaining insensitive to vibrations which can affect the machine. They must also function reliably while being substantial enough to switch high potentials.
  • the present invention relates to sensing switches, that is to say, switches which, acting on mechanical information, have the effect of automatically making or breaking the current in an electrical circuit and thereby causing decisive effects, such as the stopping or starting of electrical motors, a change in their running, the operation ofsafety devices, etc.
  • a sensing switch comprising a first contact in the form of a ball or other roller element mounted, preferably but not necessarily, for rotation, on a resilient, conducting strip and a second contact in the form of a conducting surface against which said ball or roller is resiliently urged by said strip.
  • the second contact may be either flat, or convex to assume and emphasize the point contact between the two elements.
  • the sensing switch is used to control relays by the intermediates of a transistor amplifier acting as a binary switch with the potential of the current established by the contact of the ball with its support in the order of a few millivolts. This very low control potential avoids the spark erosion of the contacts, which seriously affects the sensitivity and precision of conventional sensing switches.
  • the contact between the ball or roller and the surface which is strictly a point or line contact, is very precise and its sensitivity is only a function of the elasticity and resistance of the pieces of metal of which it consists. It can thus be as high as one wishes.
  • the ball or roller is arranged at the end of a metallic strip through which the current reaches it.
  • the metallic strip is chosen to be as resilient as possible, strips of foil being perfectly suitable for this purpose. Their resilience, which can be made to increase progressively by using superimposed staggered strips, also makes it possible to control the contact pressure of the ball or roller on the surface of the second contact.
  • the sensing switch may be arranged as a shunt on one arm of a bridge which provides the base potential of a transistor acting as an amplifier.
  • the transistor functions as a switching device.
  • the making or breaking of the current of the bridge in the shunt circuit which is controlled by the sensing switch changes the base potential of the transistor and allows it to operate in the blocked state or conducting state and vice versa.
  • the shunt is broken and the transistor base is at the operating potential.
  • the transistor conducts and effectively makes a high power circuit.
  • the base is retuned, to earth potential and the transistor is blocked.
  • the present invention gives ball contacts a switching efficiency not previously available.
  • the ball contact is required to break only a low potential current while its combination with the transistor amplifier permits the switching of heavy loads.
  • the resulting efficiency of the ball contacts as employed in the present invention is unparalleled. Spark erosion of the ball contact is avoided while instantaneous response is achieved.
  • the device is extremely sensitive yet rugged and capable of withstanding long hours of constant use.
  • Still another object of this invention is to provide a sensing switch assembly having a ball contact actuated by thin sheet material which can switch heavy loads without spark erosion of the contact.
  • Another specific object of the invention is to provide a laminated metallic strip for carrying the ball contact and an adjustable pressure mounting for the ball contact.
  • Yet another object of the invention is to provide a sensing switch including a ball contact and a plate arranged to be actuated by sheet material with the switch of the ball and plate arranged as a shunt on one arm of a bridge which provides the base potential of the transistor acting as an amplifier.
  • Still another specific object of this invention is to provide a switch for controlling a copy machine wherein the power to the controlled load is supplied through a circuit including a transistor and the base potential of the transistor is controlled by a switch having ball and plate contacts.
  • FIG. 1 is a schematic side elevation, in section, of one embodiment of sensing switch according to the invention.
  • FIG. 1 there is illustrated a sensing switch including a ball 1 rotatably fixed for example, by crimping, at one end of a strip of foil 2.
  • the strip is shown of laminated construction including a long strip 2a which actually carries the ball, 7 and shorter strips 2b, 20, etc., the strips being clamped by screws 9 to a contact 4.
  • the ball is urged by the resilience of the strip into contact with the upper surface of a conducting plate 3, which is mounted in an insulating table 5.
  • the force with which the ball is urged against the plate 3 may be adjusted by rotating the contact 4 about the insulated mounting pivot 8, the contact 4 being locked by means of the screw in any desired position.
  • a guide 7 is spaced from the table 5 and feeds sheets of papers 6 or other insulating material to be detected, between the ball 1 and the plate 3. Electrical leads from the plate 3 and the terminal 4 are placed across the points E and B in one of the circuits illustratedin FIGS. 2 to 5, in each of which the transistor 11 has a potential divided AEB, the base being connnected to the center point E of the divider.
  • resistors R and R are bias resistors which operate to control the transistor 11.
  • resistors R-2 and R4 When the switch across EB is open, current is caused to flow through resistors R-2 and R4 since the transistor will be biasedto a conducting state.
  • resistors R-2 and R4 When the transistor 11 is in the conducting state, a high current is caused to flow through R4, the current controlling the load of the copy machine for which the sensing switch is provided.
  • FIGS. 2 to 5 show different connecting switch.
  • relay R is placed in the emitter circuit of the transistor and the contacts of this relay serve to operate the load C.
  • the microswitch of this invention can thus be used to effect instantaneous control of large currents. This control is effective even though the actual switch current broken by the contact of the ball and plate is small.
  • Devices constructed in ac cordance with the present invention are particularly effective to control electro magnetic clutches and brakes in a duplicating machine in response to the movement of a thin sheet of material, as the material arrives at a particular location in the machine, etc'.
  • Iclaim 1.
  • a sensing switch for detecting the presence or absence of a sheet of paper on said feedplate and having a normally closed state in the absence of a sheet of paper on said feedplate, and an open state when a sheet of paper is present on said feedplate;
  • said sensing switch including said feedplate as a first electrically conductive contact, an electrically conductive ball as a second contact, an elongated, resilient metallic strip having a first end supporting said ball to be freely rotating and a second end, and means for securing said second end of said strip to a standard affixed to the copying machine, -the resilience of said strip being sufficient to absorb vibrations of the copying machine;
  • said ball being supported adjacent said feedplate and normally biased toward said feedplate by said strip such that said ball and saidfeedplate are continuously in electrical contact in the absence of a sheet of paper on said feedplate to place said sensing switch in said closed state and said ball is moved away from said feedplate in response to the presence of a sheet of paper on said feedplate to place said sensing switch in said open state;
  • a control circuit connected with said sensing switch including a transistor coupled with a load for operating feed roller means for the copying machine, said transistor having a conductive state to energize said load when said sensing switch is in said open state in response to the presence of a sheet of paper on said feedplate and having a nonconductive state to deenergize said load when said sensing switch is in said closed state in response to the absence of a sheet of paper on said feedplate.
  • strip is constructed of a plurality of strips of metallic foil, each of said strips of foil having a different length.

Landscapes

  • Mechanisms For Operating Contacts (AREA)
  • Controlling Sheets Or Webs (AREA)
  • Sheets, Magazines, And Separation Thereof (AREA)
US3590270D 1968-04-12 1969-04-11 Sensing switch Expired - Lifetime US3590270A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR147896 1968-04-12

Publications (1)

Publication Number Publication Date
US3590270A true US3590270A (en) 1971-06-29

Family

ID=8648905

Family Applications (1)

Application Number Title Priority Date Filing Date
US3590270D Expired - Lifetime US3590270A (en) 1968-04-12 1969-04-11 Sensing switch

Country Status (6)

Country Link
US (1) US3590270A (xx)
BE (1) BE731351A (xx)
DE (1) DE1918742A1 (xx)
FR (1) FR1581508A (xx)
GB (1) GB1222293A (xx)
NL (1) NL6905542A (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10497521B1 (en) * 2018-10-29 2019-12-03 Xerox Corporation Roller electric contact

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9115690D0 (en) * 1991-07-19 1991-09-04 Strix Ltd Electrical contacts
FR2725831B1 (fr) * 1994-10-18 1997-01-24 Soc D Mecanique Et De Plastiqu Balai de contact electrique destine a se deplacer sur une piste conjuguee

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3006450A (en) * 1961-10-31 Sheet detector for use with printing press
US3024334A (en) * 1958-09-12 1962-03-06 Hurletron Inc Ball contacting device
US3274368A (en) * 1964-12-29 1966-09-20 Teletype Corp Laminated distributor brush
US3278715A (en) * 1965-02-03 1966-10-11 Martin S Arbonies Frictionless device for making electrical contact between moving members
US3333111A (en) * 1964-07-06 1967-07-25 Smith Corp A O Pulse switching system
US3336448A (en) * 1965-09-02 1967-08-15 Electronix Ten Inc Non-sparking switching apparatus
US3389301A (en) * 1965-10-21 1968-06-18 Fenwal Inc Arc suppressing circuit

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3006450A (en) * 1961-10-31 Sheet detector for use with printing press
US3024334A (en) * 1958-09-12 1962-03-06 Hurletron Inc Ball contacting device
US3333111A (en) * 1964-07-06 1967-07-25 Smith Corp A O Pulse switching system
US3274368A (en) * 1964-12-29 1966-09-20 Teletype Corp Laminated distributor brush
US3278715A (en) * 1965-02-03 1966-10-11 Martin S Arbonies Frictionless device for making electrical contact between moving members
US3336448A (en) * 1965-09-02 1967-08-15 Electronix Ten Inc Non-sparking switching apparatus
US3389301A (en) * 1965-10-21 1968-06-18 Fenwal Inc Arc suppressing circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10497521B1 (en) * 2018-10-29 2019-12-03 Xerox Corporation Roller electric contact

Also Published As

Publication number Publication date
NL6905542A (xx) 1969-10-14
DE1918742A1 (de) 1969-11-13
BE731351A (xx) 1969-09-15
FR1581508A (xx) 1969-09-19
GB1222293A (en) 1971-02-10

Similar Documents

Publication Publication Date Title
US2659533A (en) Touch-responsive keyboard
US3305805A (en) Proximity switch
US1894025A (en) Gauging apparatus
US3611068A (en) Contactless pressure sensitive semiconductor switch
US3668698A (en) Capacitive transducer
ES8405205A1 (es) Dispositivo detector de desgaste de escobilla para maquinas dinamoelectricas.
US3590270A (en) Sensing switch
US2401396A (en) Photoelectric control
US2523184A (en) Seam detector
GB1260027A (en) Low throw touch operable electric switches
US2881275A (en) Device for detecting workpieces such as card blanks for packets
US2116842A (en) Butt contact rotary switch
US3250955A (en) Magnetically operated switch for ignition system
US3020995A (en) Typewriter key cap switch for additional signals
US970169A (en) Electrical protective apparatus.
US3052773A (en) Combined sensing and switch device
US4758698A (en) Microswitch
US3246089A (en) Roller contact structure resiliently supported on flexible arm for measuring fin angular displacement
US3250885A (en) Flat contact piece
US4742191A (en) Keyboard proximity switch
US3536923A (en) Network for detecting resistance changes
US3204070A (en) Momentary switch using resilient leaf spring actuator
US2575957A (en) Electric switch device
US2884496A (en) Centrifugal governor switch
US3172976A (en) Magnetic proximity switch