Phonograph
AssigneeBang & Olufsen A/S
InventorN. Krebs Sorensen
Life of this patent
Estimating the term…
Abstract
A detecting arrangement for a phonograph for non-mechanically detecting a tone arm reaching the outlet groove of a record. The detecting arrangement includes a first detector in the form of an elongated member movable in accordance with the movement of the tone arm and a second detector responsive to at least an increased movement of the member for generating pulse signals above a predetermined level to a detector unit which controls an operation of the phonograph.
Claims26
A phonograph provided with means for detecting the tone arm reaching the outlet groove of a record and for effecting operation control in response to this detection, said detecting means being adapted so as to respond to an increased speed of the tone arm motion relatively to the normal playing speed thereof, characterized in that said detecting means comprise a first detector element arranged so as to be movable with said tone arm and a second detector element arranged in a stationary manner relative to the chassis of the phonograph so as to be passed by said first detector element by the movement of the tone arm at least through the path corresponding to the tone arm moving in the outlet groove of a record, one of said first or second detector elements being constituted by an elongated member extending in the direction of a relative movement between said first and second detector elements, the other of said first or second detector elements comprising a light source for illuminating a narrow area of said elongated element and photoelectric sensing means arranged so as to be operable to detect light from said light source as light reflected by said elongated member or as light admitted through transparent portions thereof, said elongated member having a row of member portions of alternating light reflectability or of alternating light transparence so as to cause said sensing means to receive a pulsating light signal in response to a relative movement between said detector elements, said sensing means being operatively connected to a detector unit including means for producing a control signal for effecting said operation control in response to the pulse frequency of said pulsating light signal increasing above a predetermined value, said elongated member being extended so as to pass along or be passed by said other detector element by the movement of the tone arm through the entire path corresponding to playing of a record of standard size, said elongated member having at least one localizer portion situated so as to be located for cooperation with said other detector element when the tone arm assumes a position corresponding to start playing of said record, said at least one localizer portion being prepared so as to cause the light signal received by said sensing means to change its character in response to the localizer portion being moved into operative engagement with said sensing means, said sensing means being additionally connected with a second detector unit operable to detect said change of light signal character and to produce an output signal in response thereto, said output signal being fed to a control circuit for a tone arm lowering arrangement so as to condition lowering of the tone arm at the correct place to start playing of the record.
A phonograph record detector for use with a phonograph having a chassis and a tone arm, and for detecting the type of record to be played and the outlet groove of the record being played, comprising:
- a first detector element adapted to be movable with the tone arm and comprising an elongated member extending in the direction of the movement of said first detector element;
- a second detector element arranged in a stationary manner relative to the chassis of the phonograph so as to be passed by said elongated member during the movement of the tone arm at least through the path corresponding to the tone arm moving in the outlet groove of a record, said second detector element comprising a light source for illuminating a narrow area of said elongated member and photoelectric sensing means adapted so as to be operable to detect light which may be transmitted through said elongated member;
- alternating areas of light transparency on said elongated member positioned to receive illumination from said light source only when the tone arm is in the proximity of the outlet groove for causing said sensing means to receive a pulsating light signal in response to the relative movement between said first and second detector elements;
- a detector unit responsive to said sensing means for producing a control signal for effecting end of record operation control in response to the pulse frequency of said pulsating light signal increasing above a predetermined value;
- at least one localizer portion positioned on said elongated member for cooperating with said second detector element when the tone arm assumes a position corresponding to the start of a record, said localizer portion being adapted so as to cause the light signal received by said sensing means to change its character in response to the localizer portion being moved into operative proximity with at least one of said light source and said sensing means;
- a second detector unit responsive to said sensing means to detect said change of light character caused by said localizer portion for producing an output signal in response to said change;
- and
- a control circuit responsive to said output signal for lowering the tone arm at the correct place to start play of the record.
In combination with a phonograph having a chassis and a tone arm, the improvement comprising:
- a first detector element adapted to be movable along with the tone arm at least through the path corresponding to the tone arm moving in the proximity of the beginning edges of records of standard sizes;
- a second detector element arranged in a stationary manner relative to the chassis of the phonograph so as to be passed by said first detector element during the movement of the tone arm when the tone arm is in the proximity of the areas corresponding to the outer edges of records of standard sizes;
- one of the first and second detector elements comprising an elongated member, the other of said first and second detector elements comprising a light source for illuminating a narrow area of said elongated member and photoelectric sensing means arranged so as to be operable to detect light which may be transmitted through said elongated member;
- at least one localizer portion on said elongated member positioned so as to be located for cooperation with said light source and said sensing means when the tone arm assumes a position corresponding to the start of a record, said localizer portion being adapted so as to cause the light signal received by said sensing means to change its character in response to the localizer portion being in operative proximity with at least one of said light source and said sensing means;
- a detector unit responsive to said sensing means to detect said change of light signal character caused by said localizer portion for producing an output signal in response to said change;
- and
- a control circuit responsive to said output signal for lowering the tone arm at the correct place to start play of the record.
In combination with a phonograph having a chassis and a tone arm, the improvement comprising:
- a first detector element adapted to be movable along with the tone arm at least through the path corresponding to the tone arm moving in the proximity of the beginning edges of records of standard sizes, said first detector element comprising an elongated member extending in the direction of movement of said member;
- a second detector element arranged in a stationary manner relative to the chassis of the phonograph so as to be passed by said elongated member during the movement of the tone arm when the tone arm is in the proximity of the areas corresponding to the outer edges of records of standard sizes, said second detector element comprising a light source for illuminating a narrow area of said elongated member and photoelectric sensing means arranged so as to be operable to detect light which may be transmitted through said elongated member,
- at least one localizer portion on said elongated member positioned so as to be located for cooperation with said second detector element when the tone arm assumes a position corresponding to the start of a record, said localizer portion being adapted so as to cause the light signal received by said sensing means to change its character in response to the localizer portion being moved into operative proximity with at least one of said light source and said sensing means;
- a detector unit responsive to said sensing means to detect said change of light signal character caused by said localizer portion for producing an output signal in response to said change;
- and
- a control circuit responsive to said output signal for lowering the tone arm at the correct place to start play of the record.
Dependencies are inferred from the claim text.