US3619531A - Contact assembly for an electronic musical instrument - Google Patents

Contact assembly for an electronic musical instrument Download PDF

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Publication number
US3619531A
US3619531A US3905A US3619531DA US3619531A US 3619531 A US3619531 A US 3619531A US 3905 A US3905 A US 3905A US 3619531D A US3619531D A US 3619531DA US 3619531 A US3619531 A US 3619531A
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US
United States
Prior art keywords
contact element
fixed
movable
movable contact
distance
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
US3905A
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English (en)
Inventor
Shin-Ichi Murakami
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.)
Nippon Gakki Co Ltd
Original Assignee
Nippon Gakki Co Ltd
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 Nippon Gakki Co Ltd filed Critical Nippon Gakki Co Ltd
Application granted granted Critical
Publication of US3619531A publication Critical patent/US3619531A/en
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Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H1/00—Details of electrophonic musical instruments
    • G10H1/32—Constructional details
    • G10H1/34—Switch arrangements, e.g. keyboards or mechanical switches specially adapted for electrophonic musical instruments
    • G10H1/344—Structural association with individual keys
    • 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
    • H01H1/18—Contacts characterised by the manner in which co-operating contacts engage by abutting with subsequent sliding
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H2220/00—Input/output interfacing specifically adapted for electrophonic musical tools or instruments
    • G10H2220/155—User input interfaces for electrophonic musical instruments
    • G10H2220/265—Key design details; Special characteristics of individual keys of a keyboard; Key-like musical input devices, e.g. finger sensors, pedals, potentiometers, selectors
    • G10H2220/275—Switching mechanism or sensor details of individual keys, e.g. details of key contacts, hall effect or piezoelectric sensors used for key position or movement sensing purposes; Mounting thereof

Definitions

  • the present invention relates generally to a contact assembly for an electronic musical instrument including a fixed contact element of electrically conductive rubber or like elastic material and a movable contact element of electrically conductive metallic material, and more particularly to a contact assembly so constructed as to minimize the noise which may be generated when the both elements contact with each other.
  • metallic contact elements have been commonly used in a contact assembly of a keyboard switch for an electronic musical instrument; But tones produced by the electronic musical instrument employing such metallic contact elements are not pleasing to the ear and musically undesirable because accompanying clicking sound due to the abrupt switching of the elements or due to the fact that they make no gradual contact with each other.
  • contact elements made of electrically conductive rubber or like elastic material (which will be hereinafter referred to as elastic contact element) have become used as fixed contact elements in a contact assembly.
  • the elastic contact element makes gradual contact with a movable metallic contact element during the operation of a key and effectively prevents the occurring of the clicking sound as may be generated by the abrupt switching of metallic contact elements.
  • the fixed elastic contact element has a certain disadvantage as described below.
  • this noise is mainly due to the sliding movement of the movable metallic element on the fixed elastic contact element of the contact assembly. That is, l have found that noise is likely to emanate from the rubbed elastic contact element because it has a physical property of elasticity and because its coefficient of friction is larger than that of the metallic contact element. Further, I have found that such noise can be reduced to a minimum by making the movable element slide on the fixed elastic element in reciprocal manner (i.e. the former slides on the latter in one direction and then turns back and slides in the opposite direction), with minimum sliding distance.
  • FIG. 1 is a side view showing a keyboard switch for an electronic musical instrument
  • FIG. 2 is a diagrammatic side view showing a contact assembly of the keyboard switch
  • FIG. 3 is a diagram showing relationship between stroke of actuator and contacting position of the movable and fixed contact elements on the movable element.
  • FIG. 4 is a diagram showing forms of sliding movement of the movable contact element.
  • the keyboard switch shown in FIG. 1 includes a fixed elastic contact element 1 made of electrically conductive rubber or other elastic material and a movable contact element 2 arranged at substantially right angles to said fixed contact element and made of gold-plated metallic wire.
  • the fixed contact element 2 is arranged in transverse direction in a frame 3 of the keyboard switch, while the movable contact element 2 is arranged in longitudinal direction therein.
  • the movable contact element 2 is fixed at its one end 4 on the frame 3 and is movable at its other end.
  • the movable element 2 includes a horizontal portion 5 extending along a horizontal base line thereof and an inclined portion 6 extending from the end of the horizontal portion 5 at an angle to said horizontal base line.
  • An actuator 7 slidably mounted in the vertical direction in the frame 3 engages with the inclined portion 6 of the movable contact element 2.
  • the actuator 7 When the actuator 7 is depressed by a key 8 of the electronic musical instrument, it acts to move the movable contact element downward into contact with the fixed contact element 1 (first stage of the stroke of the actuator) and then deform said movable contact element while producing sliding movement of the movable contact element on the fixed contact element (second stage of the stroke of the actuator).
  • FIG. 2 is a diagrammatic view showing the relationship between the fixed elastic contact element 1 and the movable metallic contact element 2.
  • the movable contact element 2 is shown in its free condition with no actuator assembled therewith, where the inclined portion 6 is arranged at an angle 0 with respect to a horizontal base line 9.
  • the element 2 is assembled with the actuator 7, it is lowered to the position shown by a broken line 2.
  • the element 2 is lowered to the position shown by a dot-and-dash line 2" the first stage of the stroke of the actuator 7) to make contact between the movable and fixed contact elements and then it is deformed to the position shown by a double dot-and-dash line 2" (the second stage of said stroke) while maintaining the contact between the movable and fixed contact elements.
  • the movable contact element 2 makes sliding movement on the surface of the fixed elastic element 1.
  • the sliding movement namely, a unidirectional sliding movement and a reciprocal sliding movement, depending on the shape of the movable contact element and the relative position of the movable and fixed contact elements.
  • the unidirectional sliding movement the movable contact element slides in push or pull direction on the fixed elastic contact element, and in the reciprocal sliding movement the movable contact element slides in the push direction and then turns back and slides in the pull direction.
  • the push direction means the direction in which the contacting position of the movable and fixed contact elements on the movable element moves towards the fixed end of the movable element as the key is depressed, while the pull direction means that in which said contacting position moves towards the free end portion of the movable element.
  • FIG. 3 shows the relationship between the stroke of the actuator and the contacting position of the movable and fixed contact elements on the movable element in the push and pull directions.
  • the curves C and C illustrate the unidirectional sliding movement in the pull direction.
  • the curves C and C illustrate the reciprocal sliding movement, wherein the curve C;, illustrates the case where the ratio of the sliding distance X in the push direction to the sliding distance X in the pull direction is 1:2 and the curve C illustrates the case where the ratio of the sliding distance Y in the push direction to the sliding distance Y in the pull direction is 1:1.
  • the curves C and C shown the unidirectional sliding movement in the push direction.
  • the form of the sliding movement depends on the distance A between the fixed contact element and the fixed end 4 of the movable contact element, the distance B between the actuator 7 and the fixed end 4 of the movable contact element, the stroke S of the actuator until the actuator reaches the most depressed position after the movable contact element has come into contact with the fixed contact element (namely, the above-mentioned second stage of the stroke of actuator), the length L of the horizontal portion 5 of the movable contact element, the angle 0 of the inclined portion 6 with respect to the horizontal base line 9 and the distance 1 between the fixed contact element and the horizontal base line 9.
  • the noise due to the sliding movement of the movable contact element on the fixed contact elements can be reduced to a minimum by so setting the above factors that the movable contact element makes a reciprocal sliding movement on the fixed elastic contact element and that the ratio of the sliding distance in the push direction to that in the pull direction is from about 1:1 to about 1:2.
  • the distance A, the distance B and the stroke S are substantially constant, depending on the size of the contact assembly. Consequently, the best result can be obtained by the setting of the length L, the angle and the length 1.
  • FIG. 4 the ordinate indicates the length L and the abscissa indicates the angle 0.
  • the movable element makes unidirectional movement in the pull direction in the area above the curve D,, unidirectional movement in the push direction in the area below the curve E, and reciprocal movement in the push and pull directions in the area between the curves D, and 12,.
  • the area indicated by U, above the group of the curves D,--D is a unidirectional sliding range wherein the movable contact element makes sliding movement in the pull direction, independently of the value of the distance I, while the area indicated by U below the group of the curves E,D is another unidirectional sliding range wherein the movable contact element makes sliding movement in the push direction, independently of the valve of the distance 1.
  • the area indicated by R between the groups of the curves D,-D and E,-E, is a reciprocal sliding range where the movable contact element makes sliding movement in the push direction and then in the pull direction.
  • the area T, enclosed by the upper group of the curves D,D and the area T, enclosed by the lower group of the curves E,-E are ranges where the movable contact element makes either unidirectional sliding movement or reciprocal sliding movement, depending on the value of the distance I provided that the 1 changes from 1 mm. to 5 mm.
  • L(mm.) %(mm./degree)6(degree):2.5(mm.) where l0 0 30.
  • a contact assembly for an electronic musical instrument including a fixed contact element made of electrically conductive elastic material, a movable contact element made of electrically conductive metallic material arranged at substantially right angle to said fixed contact element and fixed at its one end and means for actuating said movable contact element, said movable contact element having a horizontal portion extending along a horizontal base line thereof and an inclined portion extending from end of said horizontal portion at an angle to said horizontal base line; the improvement wherein a distance A between the fixed contact element and the fixed end of the movable contact element, a distance B between said actuating means and the fixed end of the movable contact element, a length of stroke of said actuating means between a position in which said actuating means moves said movable contact element into initial contact with said fixed contact element and the most depressed position of said actuating means, a length L of said horizontal portion of the movable contact element, an angle 0 of said inclined portion of the movable contact element with respect to the horizontal base line and a distance I between the fixed contact

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Push-Button Switches (AREA)
  • Contacts (AREA)
  • Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
  • Electrophonic Musical Instruments (AREA)
US3905A 1969-01-21 1970-01-19 Contact assembly for an electronic musical instrument Expired - Lifetime US3619531A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP383569A JPS542086B1 (de) 1969-01-21 1969-01-21

Publications (1)

Publication Number Publication Date
US3619531A true US3619531A (en) 1971-11-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US3905A Expired - Lifetime US3619531A (en) 1969-01-21 1970-01-19 Contact assembly for an electronic musical instrument

Country Status (2)

Country Link
US (1) US3619531A (de)
JP (1) JPS542086B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4090053A (en) * 1974-10-30 1978-05-16 Anton Schaumann Spring contact switch assembly

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068334A (en) * 1959-07-24 1962-12-11 Gibbs Mfg & Res Corp Keyboard for electrical instrument
US3098888A (en) * 1961-03-21 1963-07-23 Electro Voice Electrical musical instrument
US3317684A (en) * 1964-02-21 1967-05-02 Wurlitzer Co Stop tablet and filter assembly with improved separable resilient positioning means
US3480744A (en) * 1966-10-31 1969-11-25 Victor Company Of Japan Key switch for electronic keyed instruments

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068334A (en) * 1959-07-24 1962-12-11 Gibbs Mfg & Res Corp Keyboard for electrical instrument
US3098888A (en) * 1961-03-21 1963-07-23 Electro Voice Electrical musical instrument
US3317684A (en) * 1964-02-21 1967-05-02 Wurlitzer Co Stop tablet and filter assembly with improved separable resilient positioning means
US3480744A (en) * 1966-10-31 1969-11-25 Victor Company Of Japan Key switch for electronic keyed instruments

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4090053A (en) * 1974-10-30 1978-05-16 Anton Schaumann Spring contact switch assembly

Also Published As

Publication number Publication date
JPS542086B1 (de) 1979-02-02

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