US 4,634,126 AGranted

Device for converting the amount of a mechanical displacement into electrical signal

AssigneeKabushiki Kaisha Universal

InventorYutaka Kimura

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Abstract

A transducer converts the amount of mechanical displacement of a member into an electrical signal by magnetic induction. Two fixed coils different in winding direction from each other are spaced apart from each other by a suitable distance and connected in series. Inside the fixed coils, a movable coil is disposed which moves in cooperative association with the member whose amount of movement is to be detected. With the movable coil supplied with an a.c. current, the fixed coils produce an induction current whose amplitude varies with the relative position of the movable coil. A signal processing circuit generates a pulse having a duty ratio corresponding to the amplitude of the induction current. This pulse is converted into a d.c. current in a smoothing circuit to obtain a d.c. voltage corresponding to the amount of mechanical displacement. In a pinball machine, the amount of this voltage regulates the force with which the plunger of a solenoid strikes a ball, thereby to correlate the amount of movement of a handle manipulated by the player with the trajectory of the ball on a playing field.

Claims6

Dependent claims

A transducer for converting the amount of mechanical displacement of a member (1) into an electrical signal, comprising:

first coil means (9) driven by an a.c. signal (L1);
second means (11, 12) disposed adjacent to said first coil means (9) for generating an induction current (L3) that varies as the change of a magnetic field produced by said first coil means (9), said second means comprising two coils (11, 12) opposite in winding direction to each other, said two coils (11, 12) being connected in series and spaced apart from each other by a predetermined distance;
a movable member (8) moved by said member (1) for changing the spatial relations between said first coil means (9) and said second coil means (11, 12) by making said first and second coil means move relative to each other;
means (23, 24, 25, 26) for converting the amplitude of said induction current (L3) into the duty ratio of a pulse (L6), said means comprising:
a first comparator (25) for comparing said a.c. signal (L1) with a reference potential;
a delay circuit (23) for delaying said a.c. signal (L1) by a predetermined angle in phase;
a second comparator (24) for comparing an output signal (L2) from said delay circuit (23) with said induction current (L3);
and an exclusive OR gate (26) for inputting the output signals from both comparators (25, 24);
and
means (27) for smoothing and converting said pulse (L6) into a d.c. current.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/716,192Filed 26 Mar 1985
Priority: JP 59-41832[U]26 Mar 1984
Granted: 6 Jan 1987
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

A63F 7/26
Devices controlled by the player to project or roll-off the playing bodies: electric or magnetic
G01D 5/2073
By influencing the mutual induction between two or more coils: by movement of a single coil with respect to two or more coils
G01D 5/246
Influencing characteristics of pulses or pulse trains; generating pulses or pulse trains: by varying the duration of individual pulses
H03K 7/08
Modulating pulses with a continuously-variable modulating signal: duration or width modulation ; Duty cycle modulation