JPS62248175A - Position detecting device for pickup - Google Patents

Abstract

PURPOSE:To accurately detect the position of a pickup by forming a method to grasp the moving of the pickup as a sliding distance generated by extending the said moving through gear device. CONSTITUTION:The pickup 1 moves in a straight and reciprocating movement, and its position is detected by the distance of the movement. As the first rack gear 4 mounted with the pickup 1 moves, the first wheel gear 5 rotates, and a second wheel gear 6 mounted coaxially with the gear 5 are rotated to move the second rack gear 8 engaged with the gear 6. Since the diameter of the gear 6 is made longer than that of the gear 5, the length of the moving of the pickup 1 is represented by the length of the moving of the gear 8 which is the former length extended by the tooth-number ratio between the gears 6 and 5. The sliding length on an electrical resistor 3 of a brush 2 fixed on the gear 8 is longer than the sliding length identical to the distance of the moving of the gear 4. As a result, a detection error due to the ununiformity of a sliding plane and the resistor 3 can be made less.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting the position of a pickup of a player such as a laser disc or a compact disc.

[Summary of the Invention] The present invention expands the movement of a pickup, which reciprocates on a straight line, of a player such as a laser disc or a compact disc, through two sets of transmission mechanisms consisting of a rack gear and a wheel gear. A brush in contact with an electrical resistor is slid, and the position of the pickup can be determined with high accuracy based on the change in electrical resistance between one end of the electrical resistor and the brush.

[Prior Art] As a device for electrically determining the position of a linearly moving pickup, there have conventionally been devices shown in FIGS. 3 and 4.

In the figure, 51 is a pickup that moves left and right;
Reference numeral 2 denotes a brush attached to the lower surface of the pickup 51, and the brush 52 slides together with the pickup 51 on an immovable electrical resistor 53 (hereinafter simply referred to as resistance).

This device can determine the position of the pickup 51 from the change in resistance value between the brush 52 and one end (for example, the left end) of the resistor 53.

[Problems to be Solved by the Invention] However, with the above-mentioned device, the position of the detected pickup 51 may be affected due to the condition of the sliding surfaces of the brush 52 or the resistor 53, or the non-uniformity of the resistance value of each part of the resistor 53. , a slight error will occur.

[Means for Solving the Problems] The present invention aims to solve the above-mentioned problems by expanding the movement of the pickup via a deceleration mechanism consisting of a rack gear, a wheel gear, etc. and causing the brush to slide. It is something that

[Operation] According to the present invention, the brush, which moves significantly more than the amount of movement of the pickup, slides on a resistance using a speed reduction mechanism including a rack gear, a wheel gear, etc., and detects the position of the pickup with high accuracy.

[Embodiment of the invention] Figures 1 and 2 show an embodiment of the present invention.
and 2 are the same pickup and brush as 51 and 52 above, respectively, and 3 is a resistor corresponding to 53 above.

A first rack gear 4 facing in the left-right direction is fixedly installed on the lower surface of the pickup 1, and a small-diameter first wheel gear 5 meshes with a row of teeth provided on the lower surface of the first rack gear 4.

On the side of the first wheel gear 5, there is a coaxial large-diameter second wheel gear.
Wheel gear 6 is fixed, and both wheel gears 5 and 6 are
It is pivotally installed on the immovable member 7.

The second wheel gear 6 meshes with a row of teeth on the upper surface of a second rack gear 8 which is parallel to the first rack gear 4.

The brush 2 is attached to the lower surface of the second rack gear 8 and slides on the resistor 3.

In the above-mentioned device, when the first rack gear 4 on which the pickup 1 is mounted moves, for example, in the direction of the arrow, the first rack gear 4 moves in the direction of the arrow. Both second wheel gears 5 and 6 rotate, and the second rack gear 8 moves in the direction of the arrow along with the brush 2.

Let the amount of movement of the first rack gear 4 be Q, the amount of movement of the second rack gear 8 be Q, the number of teeth of the first wheel gear 5 be N, and the number of teeth of the second wheel gear 6 be n. As is well known, the following relationship exists.

Q: LX- That is, by increasing the ratio of the number of teeth between the second wheel gear 6 and the first wheel gear 5, the amount of movement of the brush 2 can be significantly expanded compared to the amount of movement of the pickup 1.

At this time, the length of the resistor 3 also needs to be increased in accordance with the amount of movement of the brush 2.

[Effects of the Invention] As described above, according to the present invention, the amount of movement of the pickup is significantly expanded by the reduction mechanism including the rack gear and the wheel gear, and the substantial length of the resistance is also increased. Even if the play in the moving device, the condition of the sliding surface of the brush or resistor, or the uniformity of the resistance value of each part of the resistor is the same as that of the conventional one, the negative effects are reduced and the detected pickup Position accuracy is significantly improved.

Note that the speed reduction mechanism is not limited to that of the above embodiment, and various types of resistors may be used, and detection methods using optical sensors and magnetism may also be used. Can be applied.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a side view of a conventional device. FIG. 4 is also a front view. 1...Pickup, 2...Brush. 3... Resistance, 4... First rack gear, 5... First wheel gear, 6... Second wheel gear, 8... Second rack gear.

Claims (1)

[Claims] In a device that changes the resistance value of a resistor according to the amount of movement of the pickup and detects the position of the pickup from the resistance value, a deceleration mechanism is provided between the pickup and the resistor to expand the amount of movement of the pickup. A pickup position detection device characterized in that the pickup position detection device is configured to transmit information to a resistor.