# US 4,393,709 A · Direction detection apparatus

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- Number: US 4,393,709 A
- Document ID: US4393709A
- Status: Granted
- Kind: A
- Application number: 06/320,519
- Filed: 1981-11-12
- Granted: 1983-07-19
- Earliest claimed: 1980-11-13
- Assignees: Alps Electric Co., Ltd.
- Inventors: Masatoshi Harumatsu; Makoto Tomoyori; Noboru Tsushima
- Web page: https://patentgrep.com/patent/US4393709A

## CPC

- G01C 21/10: by using measurements of speed or acceleration (G01C21/24, G01C21/26 take precedence)
- G01P 13/02: Indicating direction only, e.g. by weather vane
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})

## Abstract

A direction detection apparatus which detects the traveling direction of a moving object on the basis of the movement of a weight. It comprises a centrifugal force detector, a clock signal generator, and a velocity detector, and also a detection device which receives signals from the detectors and the generator to provide a directional angle.

## Claims

### Claim 1

A direction detection apparatus comprising a centrifugal force detector including a weight and a detecting means for detecting a movement of said weight and generating a centrifugal force signal, a clock signal generator generating a time signal, a velocity detector generating a velocity signal, and a computation means connected to said force detector, clock signal generator and velocity generator to compute a directional angle on the basis of said centrifugal force signal, said time signal and said velocity signal.

### Claim 2 (depends on 1)

A direction detection apparatus according to claim 1, wherein said detecting means of said centrifugal force detector is constructed of thread resistors which are expanded and contracted by the movement of said weight.

### Claim 3 (depends on 1)

A direction detection apparatus according to claim 1, wherein said detecting means of said centrifugal force detector is constructed of pressure-sensitive resistance elements whose resistances are changed by the movement of said weight.

### Claim 4 (depends on 1)

A direction detection apparatus according to claim 1, wherein said detecting means of said centrifugal force detector is constructed of a piezoelectric transducer in the form of a cantilever and said weight is mounted on said cantilever.

### Claim 5 (depends on 1)

A direction detection apparatus according to claim 1, wherein said detecting means of said centrifugal force detector is constructed of an electrostriction transducer on which said weight is mounted.

### Claim 6 (depends on 1)

A direction detection apparatus according to claim 1, wherein said detecting means of said centrifugal force detector is constructed of a diaphragm which allows a surface elastic wave to pass therethrough and on which said weight is mounted.