JPH04285808A - Detecting device for rotational angle of gear - Google Patents

Abstract

PURPOSE:To make it possible to reduce circuit systems for providing a waiting time only to the one which corresponds only to the case when a first light- sensing element senses light. CONSTITUTION:A detecting device 201 of a rotational angle of a gear is so designed that a plurality of detecting holes 202a, 202b, 202c and 202d formed in a drive gear 13b are detected by a photodetector 203 for which phototransistors 204a and 204b being first and second light-sensing elements and light-emitting diodes 205a and 205b being light-emitting elements are used. The end face on the circumferential-direction detection position (b) side of the through hole 202a out of the through holes 202a and 202b juxtaposed toward the center of the drive gear 13b is formed nearer onto the detection position (b) side than the through hole 202b so that the through hole 202a is detected earlier by the phototransistor 204a on the occasion when the drive gear 13b rotates from the detection position (b) to a detection position (a). According to this constitution, only a circuit system for providing a waiting time which corresponds to the case when the phototransistor 204a senses light, is provided.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear rotation angle detection device for detecting the rotation angle of a gear used in electrical equipment such as a cassette loading device of a tape recorder or a disk loading device of an optical information recording/reproducing device.

0003

[Prior Art] Conventionally, a video tape recorder (VTR)
In a recording/playback device such as a digital audio tape recorder (DAT), a tape cassette is stored in a cassette holder through a cassette insertion slot, and when the detection means detects that the tape cassette is stored in the cassette holder, the device The cassette is conveyed horizontally toward the inside, and then conveyed vertically downward, and the cassette is placed on a predetermined reel stand to complete cassette loading. On the other hand, when discharging a loaded cassette, the cassette is conveyed vertically upward from a predetermined reel stand, then horizontally conveyed toward the cassette insertion slot, and when the cassette holder comes to the cassette discharge position, The cassette is pushed out from the cassette holder by the cassette pushing member and ejected from the cassette insertion port. Furthermore, in this device, in order to transport the cassette holder, both sides of the cassette holder are held by levers, and power from a drive motor is applied to the levers via a plurality of relay shafts. In a cassette loading device that performs such an operation, a plurality of detection holes are provided in the drive gear to which the lever is attached, and the rotation angle of the drive gear is detected by detecting the detection holes with a photodetector.
The position of the cassette holder was being detected.

FIG. 8 is a side view showing a gear rotation angle detection device for detecting the rotation angle of such a drive gear.

In FIG. 8, a gear rotation angle detection device 71
are a plurality of detection holes 72a, 7 formed in the drive gear 72.
2b, 72c, 72d are phototransistors 74a, 74
b and a photodetector 73 using a light emitting diode.

The photodetector 73 has a casing made of plastic or the like to sandwich the plate surface of the driving gear 72, and phototransistors 74a and 74b are installed in the casing on the front side of the driving gear, respectively. They are arranged side by side towards the center of the gear. In addition, the phototransistor 74a
, 74b are individually provided with light emitting diodes (not shown) on the back side of the drive gear of the housing.

At a detection position a for detecting the cassette ejection position (cassette holder standby position) of the drive gear 72, fan-shaped through holes 72a and 72b are formed at positions corresponding to phototransistors 74a and 74b. At a detection position b for detecting storage of the tape cassette in the cassette holder, a fan-shaped through hole 72c is formed at a position corresponding to the phototransistor 74b. At the detection position c where the loading completion position is detected, the phototransistor 7
A fan-shaped through hole 72d is formed at a position 72a corresponding to 4a. The phototransistor 74a receives light from the light emitting diode passing through the through hole 72a at a detection position a, and receives light from the light emitting diode passing through the through hole 72d at a detection position c. Phototransistor 74
b receives the light from the light emitting diode passing through the through hole 72b at the detection position a, and receives the light from the light emitting diode passing through the through hole 72c at the detection position b. The phototransistors 74a and 74b are connected to a drive circuit that drives the cassette loading device, and the drive circuit determines that the detection position is a when the phototransistors 74a and 74b simultaneously receive light, and the phototransistor 74
When only phototransistor 74a receives light, it is determined to be detection position b, and when only phototransistor 74a receives light, it is determined to be detection position c. Here, the through holes 72a and 72b have circumferential end surfaces at the same angle so that light is simultaneously detected by the phototransistors 74a and 74b when the drive gear 72 rotates from the detection position b to the detection position a. It is formed so that

However, in such a method, the through holes 72a and 72b are not always detected at the same time due to mounting errors of the photodetector 71, mounting errors of the drive gear 72, and the like. For this reason, if the phototransistor 74a receives light first, a circuit-wise appropriate waiting time is provided after the phototransistor 74a receives the light, and if the phototransistor 74b receives light within this waiting time, it is set as the detection position a, and the If the phototransistor does not receive light within the waiting time, it operates as the detection position c. On the other hand, if the phototransistor 74b receives the light first, an appropriate wait time is set in the circuit after the phototransistor 74b receives the light, and if the phototransistor 74a receives the light within this waiting time, the detection position is set to a, and the If the phototransistor 74a does not receive light within the time, it operates as the detection position b.

[0009]

[Problem to be Solved by the Invention] In such a conventional gear rotation angle detection device, in response to the case where the through holes are not detected at the same time, the circuit is properly adjusted after one phototransistor receives light. It is necessary to provide two circuit systems: one that provides a waiting time for the other phototransistor and one that provides an appropriate waiting time from the time the other phototransistor receives light, which makes the drive circuit complicated and requires a smaller drive circuit. This made it difficult to simplify the design and design.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a gear rotation angle detection device that can reduce the number of circuit systems that provide waiting time.

[Configuration of the invention]

0012

[Means for Solving the Problems] The present invention provides first and second light receiving elements that are arranged on one side of a gear at different distances from the center of the gear, and First and second light emitting elements are provided at positions on the other side of the gear corresponding to the light receiving elements, respectively, and the first and second light emitting elements are provided at positions corresponding to the first and second light receiving elements at the first detection position, respectively. First and second through holes through which light from the first and second light emitting elements pass are formed in the plate surface of the gear, and at a second detection position, the first and second through holes are formed at a position corresponding to the second light receiving element. A third through hole through which light from the second light emitting element passes is formed in the plate surface, and at a third detection position, the light from the first light emitting element is transmitted at a position corresponding to the first light receiving element. A fourth through hole is formed in the plate surface of the gear to allow the light to pass through, a predetermined waiting time is provided after one of the first and second light receiving elements receives light, and the first and second light receiving elements When both of the light-receiving elements receive light, it is determined to be the first detection position, and when only the second light-receiving element receives light, it is determined to be the second detection position, and only the first light-receiving element In the gear detection device that detects the rotation angle of the gear by determining the third detection position when light is received, when the gear rotates toward the first detection position, the rotation angle of the gear is determined to be the third detection position. The end face of the first through hole is preferably formed at a position where the light receiving element always receives light before the second light receiving element.

[0013]

[Operation] According to such a configuration, when the gear rotates toward the first detection position, the first light receiving element is always at a position where it receives light before the second light receiving element. Since the end face of the first through hole is formed, the circuit system that provides the waiting time only needs to be adapted to the case where the first light receiving element receives light.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 7 show an embodiment in which a gear rotation angle detection device according to the present invention is applied to a cassette loading device. FIG. 1 is a side view of the gear rotation angle detection device, and FIG. 2 is a side view of the gear rotation angle detection device. 3 is an exploded perspective view of the cassette loading device, FIG. 4 is a perspective view of the assembled cassette loading device, FIG. 5 is a front view of the cassette loading device, and FIG. 6 is a cassette loading device. A side view of the device, FIG. 7 is a plan view of the cassette loading device.

In FIG. 1, a gear rotation angle detection device 20
1 is a plurality of detection holes 202 formed in the drive gear 13b.
a, 202b, 202c, and 202d are detected by a photodetector 203 using phototransistors 204a, 204b as light receiving elements and light emitting diodes 205a, 205b (see FIG. 2) as light emitting elements. ing. In this embodiment, when the drive gear 13b rotates from the detection position b to the detection position a, the through-holes 202a and 202b are aligned toward the center of the drive gear 13b, and the through-hole 202a is first detected by the phototransistor 204a. The end face of the through hole 202a on the detection position b side in the circumferential direction is formed closer to the detection position b side than the through hole 202b so that the detection position b can be detected.

To explain the gear rotation angle detection device 201 in more detail, as shown in FIG. 2, the photodetector 203 includes a light emitting section 206 to which light emitting diodes 205a and 205b are attached, and a phototransistor 204a and 204b to which the phototransistor 204a and 204b are attached. and a light receiving section 207. The light emitting section 206 and the light receiving section 207 are assembled with the drive gear 13b sandwiched therebetween. Holes 206a and 206b are formed side by side toward the center of the drive gear 13b on the surface of the housing of the light emitting unit 206 that faces the drive gear 13b.
Light emitting diodes 205a, 205b at the bottom of a, 206b
is installed. In addition, holes 207a and 207b are formed in a side-by-side manner toward the center of the drive gear 13b on the surface of the housing of the light receiving section 207 that opposes the drive gear 13b.
Phototransistors 204a, 20 at the bottom of 7a, 207b
4b is attached. Light emitting section 206 and light receiving section 207
Mounting portions 206c and 207c are provided at positions protruding from the outer periphery of the drive gear 13b, respectively. The mounting portions 206c and 207c have through holes 206d and 207.
d is formed. Then, the light emitting section 206 and the light receiving section 2
07 with the drive gear 13b in between, insert the screws 208 into the through holes 206d and 207d,
By screwing this screw into the through hole 209 of the gas side frame 3b of the set loading device, the photodetector 2
03 is attached to the side frame 3b.

As shown in FIG. 1, the drive gear 202, at a detection position a for detecting the cassette ejection position (cassette holder standby position), uses phototransistors 204a and 204b.
Fan-shaped through-holes 202a and 202b are formed at positions corresponding to . Here, the end surface of the through hole 202a on the circumferential direction detection position b side is formed closer to the detection position b by an angle of 309 than the through hole 202b. At detection position b for detecting storage of the tape cassette in the cassette holder, 20
A fan-shaped through hole 202c is formed at a position corresponding to 4b. At the detection position c for detecting the loading completion position, a fan-shaped through hole 202d is formed at a position 202a corresponding to the phototransistor. The phototransistor 204a receives the light from the light emitting diode 205a that passes through the through hole 202a in an area A1 in which the through hole 202a is formed and includes the detection position a, and also receives the light from the light emitting diode 205a that passes through the through hole 202a.
The area C in which the through hole 202d including the through hole 202d is formed receives the light from the light emitting diode 205a that passes through the through hole 202a. The phototransistor 204b is connected to the through hole 2 in an area A2 in which the through hole 202b including the detection position a is formed.
02b, and also receives the light of the light emitting diode 205b that passes through the through hole 202c in a range B where the through hole 202c is formed and includes the detection position b. Phototransistor 204
a, 204b are connected to a drive circuit that drives the cassette loading device, and if the phototransistor 204a receives the light first, the drive circuit sets an appropriate wait time in terms of the circuit after the phototransistor 204a receives the light. When the phototransistor 204b receives light within this waiting time, it operates as a detection position a, and when the phototransistor 204b does not receive light within the waiting time, it operates as a detection position c. When the phototransistor 204c receives light, the detection position b is determined without providing a waiting time.

The overall structure of the cassette loading device will be explained with reference to FIGS. 3 to 7. In FIG. 3, a cassette loading device 1 loads a cassette holder 2 containing a tape cassette into left and right side frames 3a, 3b.
It is designed so that it can be pulled in, discharged, and moved up and down by supporting it. The left side of the cassette holder 2 is held by the first and second levers 4a and 5a on the left, and the right side is held by the first and second levers 4b and 5b on the right. 5b, the power of the drive motor 6 is transferred to the worm 7, worm wheel 8, gears 9, 10, 11, 12.
, through the drive gear 13b, and the gear 14b, the relay shaft 15, and the gear 14a are applied to the left levers 4a and 5a.
, the rotational force of the drive gear 13b is applied via the drive gear 13a. As shown in FIG. 4, the drive gear 13b has a plurality of detection holes 202a, 202b, 20 on the plate surface.
2c and 202d, and the light emitting section 206 of the photodetector 203 and the light receiving section 207 of the photodetector 203 constitute the gear rotation angle detection device 201.

The cassette holder 2, as shown in FIG.
It has a box shape that penetrates behind the cassette insertion slot of a cabinet (not shown). Extending portions 21a and 21b are formed at the rear of the left and right sides of the cassette holder 2, respectively, with steps directed outward. A cassette pushing member (not shown) is provided inside the left and right extending portions 21a, 21b.

To explain the cassette loading device 1 in more detail, the cassette holder 2 has pins 25 and 26 projecting from the front and rear sides of the cassette holder 2, as shown in FIG.
These pins 25, 26 are attached to the side frames 3a, 3b.
It is adapted to be engaged with L-shaped grooves 33 and 34 provided in the. As a result, the cassette holder 2 moves horizontally (retracted) when moving from the loading start position to the loading completion position when inserting a cassette, and moves vertically when moving from the loading completion position to the loading start position when ejecting the cassette. Move horizontally from

On the other hand, as shown in FIG. 5, the pins 25 and 26 project outward from the L-shaped grooves 33 and 34 in the assembled state.

As shown in FIG. 3, one end of the levers 4a, 4b is connected to a pin 2 protruding from the L-shaped groove 33, respectively.
5, 26, and is rotatably attached to the levers 4a, 26.
The other ends of the levers 4b are rotatably attached to one end of the levers 5a and 5b, respectively. A hole 5c is formed at the other end of the left and right levers 5a, 5b,
In this hole 5c, L of the side frames 3a and 3b are respectively inserted.
By inserting a pin 35 protruding from the lower side of the groove 33, the levers 5a, 5b are rotatably attached to the side frames 3a, 3b.

The drive gears 13a, 13b have a hole 13 in the center.
1 is formed, and this hole 131 allows levers 5a, 5
It can be rotatably attached to a pin 35 inserted through the hole 131 of b. Further, the lever 5a and the drive gear 13a are connected by means such as screwing,
Thereby, the drive gear 13a rotates (or reverses) the lever 5a. Similarly, the lever 5b and the drive gear 13b are also connected.

Light emitting section 206 and light receiving section 2 of photodetector 203
07 is assembled by sandwiching the drive gear 13b between them, as shown in FIG. Through holes 206 formed in the mounting portions 206c and 207c of the photodetector 203
The photodetector 203 is attached to the side frame 3b as shown in FIG. 6 by inserting the screw 208 into the holes d and 207d and screwing this screw 208 into the through hole 209 of the side frame 3b.

As shown in FIG. 3, the gear 12 interlocks with the drive gear 13b and is fixedly attached to the gear 11 with its axis aligned with the shaft center, so that the moment of the force applied to the gear 11 is applied to the gear 12. It is now possible to join directly. Holes 111 and 121 are formed in the centers of the gears 11 and 12, respectively, and by inserting a pin 36 protruding from the rear side of the L-shaped groove 33 of the side frame 3b into these holes 111 and 121, Gears 11 and 12 are on the side frame 3
It is rotatably attached to b.

The gear 10 interlocks with the gear 11 and has a hole 101 formed in the center, and the side frame 3
The gear 10 is rotatably attached to the side frame 3b by inserting a pin 37 protruding from the rear side of the pin 36 of b.

[0028] The gear 9 engages with the gear 10, and
It is fixedly attached to the worm wheel 8 with its axes aligned, and the moment of force applied to the gear 9 is directly transmitted to the worm wheel 8. gear 9,
The worm wheel 8 has holes 91, 8 at the center of each.
1 is formed, and by inserting a pin 38 protruding from the rear side of the pin 37 of the side frame 3b into these holes 91, 81, the gear 9 and the worm wheel 8 are rotated to the side frame 3b. It can be installed freely.

The drive motor 6 is attached to the motor attachment plate 41 by screws. A bent portion 41a is provided above the motor mounting plate 41, and by fixing this bent portion 41a to the side frame 3b with screws 42, the motor mounting plate 41 is attached to the side frame 3b. mounted on.

A driving motor 6 attached to a motor mounting plate 41 is mounted on the rear side of the pin 37 of the side frame 3b.
A through hole 39 is formed into which the right half (see FIG. 7) is inserted.

The front of the motor mounting plate 41 is bent outward to form a bent portion 41b. Bending part 4
1b is formed with a through hole 411 into which the rotating shaft 61 of the drive motor 6 is inserted, so that the rotating shaft 61 protrudes from the outer surface of the through hole 411 when attached to the motor mounting plate 41. It has become. A worm 7 is fixed to this rotating shaft 61.

In front of the pin 35 of the side frames 3a, 3b, through holes 30, 30 are formed into which the relay shaft 15 is inserted. The gears 14a and 14b have through holes 141a and 14 into which the relay shaft 15 is fitted at one end and the other end, respectively.
1b is formed. These through holes 141a, 141b
Accordingly, the gears 14a and 14b are attached to the left and right ends of the relay shaft 15 protruding from the left and right through holes 30 and 30, respectively. With the gears 14a and 14b attached to the relay shaft 15 in this way, the gears 13a and 13b are connected to the relay shaft 15, respectively.
bite into.

The operation of the above-mentioned cassette loading device 1 will be explained.

When the cassette holder 2 is in the cassette ejection position (standby position), the photodetector 203 has two through holes 202 depending on the photodiodes 204a and 204b.
a, 202b are detected. The tape cassette 51 is inserted into the cassette holder 2 through a cassette insertion port (not shown). First, in this state, the cassette holder 2 slides a predetermined distance toward the back, and the tape cassette 51
is held in the cassette hold position. As a result, the photodetector 203 detects the through hole 202c with the photodiode 204b, and when a detection device (not shown) detects that the tape cassette 51 is held at the cassette hold position, the drive circuit activates the drive motor. 6 rotates the cassette in the loading direction, and this rotational force is applied to the lever 4b on the right side through the worm 7 → worm wheel 8 → gear 9 → gear 10 → gear 11 → gear 12 → drive gear 13b shown in FIG. , 5b, and the gears 14b, 5b are transmitted to the left drive gear 13a.
Right drive gear 13b via relay shaft 15 and gear 14a
The rotational force of is transmitted. As a result, the rotational force of the drive motor 6 in the loading direction is applied to the left and right drive levers 5a and 5b, and the force of the left and right levers 5 pulls the cassette holder 2 toward the back from the left and right via the lever 4, causing the L The cassette holder 2 is moved horizontally by the guides of the grooves 33 and 34. When the horizontal movement is further completed, the lever 5a,
The force of 5b is applied to the cassette holder 2 via levers 4a and 4b.
14 by pulling the cassette holder 2 downward and vertically moving the cassette holder 2 downward by the guides of the L-shaped grooves 33 and 34.
Set it to the loading completion position shown in . When the photodetector 203 reaches this position, the photodiode 204a detects the through hole 202d, and the drive circuit stops the rotation of the drive motor 6.

When ejecting the tape cassette, the rotating shaft 61 of the drive motor 6 rotates in the direction of ejecting the cassette, and this rotational force is transmitted to the left and right levers 5a and 5b through the same path as above. As the drive gears 13a and 13b rotate, they are held. The cassette holder 2 at the loading position is pushed upward by the levers 4a and 4b, and the cassette holder 2 is vertically moved upward. As a result, the photodetector 203 no longer detects the through hole 202d. In this case, when the vertical movement ends, the levers 4a and 4b push the cassette holder 2 toward the front, horizontally moving the cassette holder 2, and the tape holder 2 comes to the cassette holding position. In this case, the photodetector 203 is connected to the through hole 2 by the photodiode 204b.
02c is detected. Thereafter, the cassette holder 2 is moved horizontally, and the photodetector 203 no longer detects the through hole 202c. After this, the photodetector 203
04a to detect the through hole 202a, then the photodiode 204b to detect the through hole 202b,
The cassette holder 2 comes to the cassette ejection position. Due to this. While the tape cassette 51 is pushed out by the cassette pushing member, the drive circuit confirms that the cassette holder 2 has come to the cassette ejection position, and the drive circuit stops the rotation of the drive motor 6.

According to such an embodiment, the drive gear 13
When b rotates from the detection position b to the detection position a, the through holes 202a,
The through hole 202a of the phototransistor 202b
04a, the through hole 202a
Since the end face of the phototransistor 7 on the detection position b side in the circumferential direction is formed closer to the detection position b than the through hole 202b, the phototransistor 7
If 4b receives light first, there is no need to provide a waiting time. For this reason, the circuit system that provides a waiting time is designed to handle only the case where the phototransistor 74a receives light first.
Since only one system is required, the drive circuit is simpler than the conventional two-system system, making it easier to downsize and simplify the design of the drive circuit.

In the embodiment shown in FIG. 1, the phototransistors 74a and 74b and the corresponding light emitting diodes 74a and 74b are arranged side by side toward the center of the drive gear 13b.
If the distances from the center of the phototransistors 74a and 74b are different from the center, the phototransistors 74a and 74b may be arranged without being lined up toward the center of the drive gear 13b. In this case, the through hole 202
a shows that when the drive gear 13b rotates from the detection position b to the detection position a, the through hole 202a is connected to the phototransistor 20.
The end face of the through hole 202a on the circumferential direction detection position b side may be formed at a position where the through hole 202a is detected earlier than the through hole 202b.

Although a light emitting diode and a phototransistor were used as a combination of a light emitting element and a light receiving element,
Other combinations may be used, such as a light valve and photodiode combination.

[0039]

As described above, according to the present invention, the circuit system that provides the waiting time only needs to be adapted to the case where the first light-receiving element receives light. The circuit becomes simpler, making it easier to downsize the drive circuit and simplify its design.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of a gear rotation angle detection device according to the present invention.

FIG. 2 is a sectional view of the gear rotation angle detection device shown in FIG. 1;

FIG. 3 is an exploded perspective view of a cassette loading device to which the gear rotation angle detection device of FIG. 1 is applied.

FIG. 4 is a perspective view of the cassette loading device of FIG. 3 in an assembled state.

FIG. 5 is a front view of the cassette loading device of FIG. 3.

FIG. 6 is a side view of the cassette loading device of FIG. 3;

FIG. 7 is a plan view of the cassette loading device of FIG. 3;

FIG. 8 is a side view showing a conventional gear rotation angle detection device.

[Explanation of symbols]

1 Cassette loading device 2 Cassette holder 3a, 3b Side frame 201 Pre-opener 202 Pre-opener push-down plate 203
lid opener

Claims (1)

[Claims] 1. First and second light-receiving elements are arranged at different distances from the center of the gear at positions on one side of the gear, and the gears correspond to the first and second light-receiving elements, respectively. First and second light emitting elements are provided at positions on the other side, and from the first and second light emitting elements are provided at positions corresponding to the first and second light receiving elements at the first detection position, respectively. first and second through holes are formed in the plate surface of the gear to allow the light to pass through, and at a second detection position, the light from the second light emitting element is transmitted to a position corresponding to the second light receiving element. A third through-hole is formed in the plate surface, and the third through-hole is formed in the plate surface.
At the detection position, a fourth through hole through which light from the first light emitting element passes is formed in the plate surface of the gear at a position corresponding to the first light receiving element, and the first and second light receiving elements A predetermined waiting time is provided after one of the elements receives light, and when both the first and second light receiving elements receive light, the first detection position is determined, and the second light receiving element Detecting a gear by determining the second detection position when only the first light receiving element receives light, and determining the third detection position when only the first light receiving element receives light, thereby detecting the rotation angle of the gear. In the apparatus, when the gear rotates toward the first detection position, the end face of the first through hole is located at a position where the first light receiving element always receives light before the second light receiving element. A gear rotation angle detection device characterized in that a gear rotation angle detection device is formed.