JPS632443B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a surface runout detector that detects the amount of surface runout on the upper and lower surfaces of a tape reel housed in a videotape cassette or the like. It is also used as a digital display for digital display.

[Conventional technology]

Generally, the top and bottom surfaces of tape reels housed in video tape cassettes, etc. are required to be horizontal with a tolerance of less than 0.3 mm for the amount of surface runout from the standpoint of tape running and tape winding. Injection molded.

[Problem that the invention seeks to solve]

However, conventionally there has been no device that can quickly determine whether the amount of surface runout of a tape reel is within tolerance.

The present invention has been made in view of such problems, and an object of the present invention is to provide a surface runout detector that can accurately and quickly detect the amount of surface runout of a tape reel.

[Means and actions for solving problems]

The surface runout detector according to the present invention includes a rotary table on which a member to be measured is placed, a holder provided at one end with a probe that contacts the upper or lower surface of the member to be measured, and a A pedestal that supports the holder approximately in the center so as to swing according to unevenness, a guide bar installed along the holder, and a guide bar that moves the holder in the left and right directions allows the probe to move in the vertical direction. A weight that applies a biasing force to adjust the load on the measuring element to a constant pressure, and a converter located at the other end of the holder that detects the amount of swing of the holder and converts it into an electrical signal. and a means for detecting the amount of surface runout by converting the surface runout of the member to be measured into an electrical signal. Therefore, by continuously bringing the probe into contact with the surface of the rotating member to be measured, the amount of surface runout of the member to be measured is converted into the swinging motion of the holder, and this is detected and converted into an electrical signal. The amount of surface runout can be detected.

[Example] Hereinafter, a surface runout detector according to the present invention will be explained based on FIGS. 1 to 5.

Figure 1 is a front view of the surface runout measuring device, Figure 2 is a perspective view of the surface runout detector, Figures 3 and 4 are illustrations of the alignment of the weight in the detector shown in Figure 2, and Figure 5. 1 is a block diagram showing the circuit configuration of a digital display.

In FIG. 1, 50 is a surface runout detector that detects the amount of surface runout of the tape reel and converts it into an electrical signal;
11 is an analog voltmeter that displays the electrical signal;
13 is a digital display that displays the maximum value, the minimum value, and the difference between the maximum value and the minimum value of the amount of surface runout based on the electrical signal, and determines whether the amount of surface runout is within the tolerance, These constitute a surface runout measuring device.

First, the surface runout detector 50 will be explained with reference to FIG. 2. 1 is a main body of the detector; 2 is a rotary table on which a tape reel 3 as a member to be measured and a reference gauge (not shown) for the reel 3 are mounted and rotated by a motor M in the main body 1; 4 is a handle 5; The frame is configured to move up and down through the rotation of the frame. This pedestal 4 is used to adjust the vertical position of the probe, and in the illustrated example, the rotation of the handle 5 is controlled by a rack 4a formed on the shaft of the pedestal 4 via gears 5a, 5b, and 5c that mesh within the main body 1. It transmits the signal to move it up and down. Reference numeral 6 denotes a holder swingably supported by a support shaft 4b inserted through the pedestal 4, 6a a guide bar provided along the holder 6, and 6b a lower left end of the holder 6. Displacement parts 7a and 7b which are disposed and move up and down in response to the swinging of the holder 6 are conical probes provided on the upper and lower surfaces of the right end of the holder 6, and the upper probe 7a is the tape. The lower measuring element 7b contacts the lower surface 3b of the reel 3 and the upper surface 3a of the tape reel 3 to detect irregularities on the surface of the tape reel 3. 8 is a weight that slides along the guide bar 6a, and is connected to the support shaft 4b.
By sliding the holder in the left-right direction around the center, the holder is swung in the left-right rotational direction with respect to the support shaft 4b, and the measuring element 7a or 7b is attached to the lower surface 3b or upper surface 3a of the tape reel 3 as required, respectively. Bring it into contact with a biasing force. 8' is a fastening screw for fixing the weight 8 to the guide bar 6a, and 9 is a differential transformer as a conversion means in which the displacement part 6b is arranged so as to be vertically movable. This converts the amount of displacement according to the amount into an electrical signal. 10 is a lock lever for fixing the vertical position of the pedestal 4.

Next, the analog voltmeter 11 and digital display 13 will be explained in detail.

As shown in FIG. 1, the analog voltmeter 11 displays an electric signal sent from the detector main body 1 via a cord 12, that is, an electric signal representing the amount of surface runout converted by the differential transformer 9. The measurement range is such that, for example, a vertical movement of 0.1 mm of the probes 7a and 7b shows 1V, and it is possible to measure up to a maximum of ±6V and a minimum of 0.2V. Using this analog voltmeter 11, the amount of surface runout of the tape reel 3 can be checked one by one. On the other hand, the digital display 13 displays the maximum value of the electrical signals inputted from the detector body 1 via the code 12, the analog voltmeter 11, and the code 14.
3a, MIN display section 13b that displays the maximum value
and RANG that displays the difference between the maximum and minimum values.
It includes a display section 13c, a power switch 13d, a zero adjustment button 13e, a start button 13f, and the like.

FIG. 5 is a block diagram showing an example of the circuit configuration of the digital display 13, in which 15 is a pulse oscillation circuit for reading measured values at regular intervals;
6 and 17 are comparators, 18 and 19 are AND gates, 20 is an up counter, 21 is a down counter, 22 and 23 are D/A converters, 24
2 is an analog subtraction circuit, 25, 26, 27 are fine adjustment circuits, 28, 29, 30 are A/D converters, frame A indicates a maximum value holding circuit, and frame B indicates a minimum value holding circuit. In the maximum value holding circuit A, if the signal input to the input terminal IN is smaller than the maximum value held at that time, there is no output from the comparator 16, but if the input signal is larger than the maximum value, the signal from the comparator 16 is output. is input to the AND gate 18. In this state, when the pulse from the pulse oscillation circuit 15 is input to the AND gate, the signal is input to the up counter 20, and the signal from the up counter 20 is input to the D/A.
It is sent to the converter 22, but at this time the D/A
When the output of the converter 22 is smaller than the input signal, the above operations are performed continuously, and when the output of the D/A converter 22 becomes slightly larger than the input signal, the output of the comparator 16 is inverted and the new maximum value is maintained. be done. Incidentally, since the pulse oscillation circuit 15 is configured to emit, for example, 100,000 pulses per second, reading of the above-mentioned new maximum value is performed almost in real time. Since the operation of the minimum value holding circuit is almost the same, the explanation thereof will be omitted. The maximum value signal and minimum value signal obtained in this way are transmitted to each fine adjustment circuit 25, 27 and the A/D converter 28,
30 and displayed on the MAX display section 13a and the MIN display section 13b after a predetermined time from the start, and the difference therebetween is calculated by the subtraction circuit 24 and similarly displayed on the RANGE display section 13c. The circuit configuration described above is shown as an example, and any other circuit can be used as long as it can hold the maximum and minimum values during measurement and display the maximum and minimum values and their difference after a predetermined time from the start. It may be a composition.

Next, measurement of the surface runout of a tape reel using the above-mentioned surface runout detector 50 will be explained.

(a) In Figures 1 and 3, select a reference gauge (with a surface runout accuracy of 10 μM or less) for the tape reel to be measured, and place it on the rotary table 2. In this case, in order to make it easier to place the reference gauge on the rotary table 2, the weight 8 is slid to the right in advance to separate the probes 7a and 7b from the rotary table 2.

(b) After rotating the handle 5 so that the holder 6 is in a position parallel to the top surface of the reference gauge (corresponding to the top surface of the tape reel), lock it with the lock lever 10. This is done in consideration of the contact angle and contact pressure of the measuring probes 7a and 7b with respect to the upper surface of the reference gauge.

(c) Slide the weight 8 to the left of the support shaft 4b and align it with the center of the first index 6c (see Figure 3).
As a result, the holder 6 is tilted downward to the left about the support shaft 4b, and the probe 7b comes into contact with the upper surface of the reference gauge (corresponding to the upper surface of the tape reel). In this case, the contact pressure between the probes 7a and 7b is determined by the sliding amount of the weight 8, but in this measurement example, a load of about 3 to 10 grams is applied, taking into consideration the elasticity of the tape reel 3 and measurement accuracy. adjusted.

(d) To maintain this state, lock lever 10
and fastening screws 8'. This is to ensure that the tape reel 3 to be measured and the reference gauge have the same contact pressure.

(e) Zero adjustment button 13e of digital display 13
Press to set the contact position as the zero reference. Hereinafter, the surface runout of the tape reel 3 is measured by swinging the holder 6 based on this zero reference.

The zero reference adjustment is performed using "0,000" on the MAX display section 13a on which the output signal from the detector main body 1 is displayed as a guide.

(f) Push down the right side of the holder 6 with your hand and
b away from the top surface of the reference gauge and remove the reference gauge from the rotary table 2.

(g) Place the tape reel 3 to be measured on the rotary table 2 while pressing down the right side of the holder 6 as in (f) above. After that, the holding body 6 is released from being pressed down. As a result, the measuring element 7b automatically comes into contact with the upper surface 3a of the tape reel 3.

(h) A weight (not shown) on the tape reel 3
to stabilize the tape reel 3 and eliminate measurement errors.

(i) Start button 13f of digital display 13
Press to rotate the tape reel 3 on the rotary table 2. The rotation speed is about one rotation every 10 seconds. Due to this rotation, the measuring element 7b comes into contact along the peripheral edge of the upper surface 3a of the tape reel 3.

(j) The displacement portion 6b at the other end of the holder 6 is swung in response to the contact of the probe 7b, and the amount of surface runout is detected as an electric signal, and is displayed on each display section after about 12 seconds. For the same type of reel,
Measurements are performed one after another by a simple operation of replacing the reel and pressing the start button 13f, and the measured values are displayed on a digital display.

(k) When measuring the runout of the bottom surface of the reel,
As shown in FIG. 4, the adjustment is made by aligning the right end surface 8b of the weight 8 with the center of the second index 6d of the holder 6 and making the adjustment so that the measuring tip 7a is in contact with the lower surface of the reference gauge. This is almost the same as when measuring the surface runout of the upper surface.

Note that the left end surface 8a of the weight 8 and the first indicator 6c of the holder 6 are colored in one color, for example, red, and the right end surface 8b of the weight 8 and the second indicator 6d of the holder 6 are colored in one color, for example, red.
It is preferable to color each of them in another color, for example, black, as this will prevent misalignment from occurring.
Furthermore, if the digital display 13 is provided with an output terminal for a printer, the measured values can also be recorded using a printer.

As described above, according to this embodiment, the measurement of the surface runout of the tape reel, which was conventionally done manually, is automatically carried out, and the measured values are also displayed digitally, so that the measurements can be carried out quickly. Moreover, because of the digital display, there is an advantage that the measured value can be read instantly and accurately. Although the above description deals with measuring the surface runout of a reel, the present invention is applicable not only to reels but also to other disc-shaped members.

〔Effect of the invention〕

As described above, according to the surface runout detector according to the present invention, the amount of surface runout of a member to be measured such as a tape reel can be detected accurately and quickly.

[Brief explanation of the drawing]

FIG. 1 is a front view of the surface runout measuring device according to the present invention, FIG. 2 is a perspective view of the surface runout detector, FIGS. 3 and 4 are illustrations of positioning of weights in the surface runout detector, and FIG. FIG. 5 is a block diagram showing the circuit configuration of the digital display shown in FIG. 1. DESCRIPTION OF SYMBOLS 1... Detector main body, 2... Rotating table, 3... Tape reel as a member to be measured, 4... Mount, 5...
...handle, 6...holding body, 7a, 7b...measuring head, 8...weight, 9...differential transformer as electric signal conversion means, 10...lock lever, 11...
...Analog voltmeter, 12, 14...Code, 13
...Digital display, 15...Pulse oscillation circuit,
16, 17... Comparator, 18, 19... AND gate, 20... Amplifier counter, 21...
...Down counter, 22, 23...D/A converter, 24...Arithmetic circuit, 25, 26, 27...
...Fine adjustment circuit, 28, 29, 30...A/D converter.

Claims (1)

[Claims] 1. A rotary table on which a member to be measured is placed, a holder provided at one end with a probe that contacts the upper or lower surface of the member to be measured, and a holder that swings according to the unevenness of the upper or lower surface of the member to be measured. A pedestal supporting the holding body approximately at the center, a guide bar provided along the holding body, and a vertical biasing force applied to the measuring element by moving it in the left and right directions guided by the guide bar. a weight that adjusts the load of the measuring head on the member to be measured to a constant pressure by applying pressure to the member to be measured; and a conversion means that is disposed at the other end of the holding body and detects the amount of swing of the holding body and converts it into an electrical signal. A surface runout detector comprising: a surface runout detector that detects the amount of surface runout by converting the surface runout of the member to be measured into an electrical signal.