JPS628486Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a length measuring device that digitally measures the amount of movement of a workpiece in a machine tool or the like.

2. Description of the Related Art A length measuring device is a device for positioning a workpiece during machining in a machine tool or the like.

This length measuring device, for example, has a reference scale attached to the movable table side of a machine tool, and a reference scale attached to the fixed bed side.
An encoder is provided that optically, electrically, or magnetically detects the amount of movement of the reference scale, converts it into an electrical pulse signal, and outputs it, and counts the number of pulse signals output from the encoder. , by discriminating its phase,
The amount and direction of movement of the workpiece are measured.

By the way, this type of length measuring device detects the amount of relative movement between the reference scale and the encoder. For example, each time the reference scale moves relative to the encoder by a unit length, one This is a so-called incremental length measuring device that outputs pulses and measures the amount of movement of the reference scale by counting these pulse signals.

Therefore, this type of length measuring device has the great advantage of being able to set a reference point for processing positioning, that is, a processing origin, at an arbitrary position. for example,
Since the machining operation can be performed by detecting the machining reference plane of the workpiece and positioning the workpiece using this reference plane as the machining origin, the positioning operation becomes easy and is extremely effective in improving work efficiency.

Furthermore, if each machining position of the workpiece is given as a distance between each machining point, the length measuring device is reset when the machining operation at one machining position is completed, and then The next machining position can be obtained by moving by a given distance, so there is no need for any calculation means, and accurate positioning can be performed extremely easily.

However, as mentioned above, this type of incremental length measuring device does not have an absolute mechanical origin, so if a reset operation is performed in the middle of machining, the reset position becomes the new origin. The original origin disappears. Therefore, it is difficult to confirm the original position of the origin, and the task of returning the workpiece to the original origin becomes very complicated, for example.

Therefore, the present invention was devised to solve the above-mentioned problems, and includes two counter sections that count the pulse signals output from the scale section, and a reset circuit attached to each counter section. For example, one reset circuit is activated only when a so-called absolute origin is set, which is the absolute reference point for positioning the machining operation, at the start of a machining operation. By making it possible to operate arbitrarily as needed during machining and reading the counts of the two counters as appropriate, the amount of movement from the absolute origin and the machining origin arbitrarily set during machining can be adjusted. The object of the present invention is to provide a length measuring device that can read both the amount of movement of the object and the amount of movement of the object.

An embodiment of the length measuring device according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a scale unit that outputs a number of pulses according to the amount of movement of the workpiece. The encoder includes an encoder that optically, electrically, or magnetically detects the amount of movement of the scale and outputs a number of, for example, two-phase pulse signals corresponding to the amount of movement.

Reference numeral 2 denotes a direction determination circuit that determines the moving direction of the reference scale of the scale section 1 from the phase of the two-phase pulse signal output from the scale section 1; This is a first counter that adds or subtracts the pulse signal output from the scale section 1 in response to a count command or a down-count command. 4 is a first reset circuit that gives a reset command to the first counter 3;
This first reset circuit 4 is activated, for example, only at the start of a machining operation, and resets the counted contents of the first counter 3 when the workpiece is located at the absolute origin, which is the absolute reference position of one machining operation. After the reset circuit is reset, the reset circuit is not activated until at least one machining process is completed.

Further, 5 is similar to the first counter 3,
A second counter 6 that adds or subtracts pulse signals output from the scale section 1 in response to an up-count command or a down-count command output from the direction discrimination circuit 2 is used when the workpiece is being machined. This is a second reset circuit which is operated arbitrarily as necessary in order to reset the counting contents of the second counter 5.

7 is a display unit that digitally displays the counts of the first and second counters 3 and 5;
is a switching unit that switches and introduces the count values of the first and second counters to the display unit 7.

Therefore, in the above-described configuration, first, at the start of a machining operation, an absolute origin for one machining operation is set.

This absolute origin can be set arbitrarily depending on the size and shape of the workpiece or the type of machining work.For example, the end face of the workpiece is used as a reference plane, and the workpiece is moved to meet the reference plane. By detecting the plane and activating the reset circuit 4, the count content of the first counter 3 is reset at this absolute origin position, and the display value of the first counter 3 on the display section 7 is set to 0.

Next, as shown in FIG. 2, with the absolute origin set as a reference position and the switching section 8 switched to the first counter 3 side, while monitoring the display section 7, the first counter given in advance is displayed. The workpiece is moved by a distance l ₁ to the machining point, and machining is performed.

Therefore, the position of the second machining point to be machined next to the first machining point is a distance l ₂ from the first machining point.
When the machining operation at the first machining point is completed, the switching section 8 is switched to the second counter 5 side, the second reset circuit 6 is activated, and the second The count value of the counter 5 is reset, that is, the displayed value of the second counter 5 is set to 0. In this state, by moving the workpiece by a distance l ₂ while monitoring the display section 7, the second processing point can be easily positioned without using calculation means or the like. It is what it is.

In this case as well, the pulse signal output from the scale section 1 is introduced into the first counter 3, and the counting operation starting from the absolute origin is continued.

Therefore, even if the count value of the second counter 5 is reset by the second reset circuit 6, the distance L ₂ from the absolute origin to the second origin of the workpiece measured, or the second origin The distance L ₃ to the third origin where processing is performed after is the first counter 3
For example, when it is necessary to return the workpiece to the absolute origin after finishing work at the second processing point, the switching section 8 is switched to the first counter 3 side. By moving the workpiece while monitoring the display unit 7 until the displayed value becomes 0, the workpiece can be accurately returned to its original absolute origin position.

In this way, no matter how the position of each machining point is given, the optimal origin position for positioning the next machining point can be found during machining without losing the distance from the absolute origin set at the start of machining. Since it can be set arbitrarily, there is no need to use calculation methods, etc.
This makes it possible to position the processing point extremely quickly and easily.

By the way, in the embodiment described above, by switching one display section 7 by the switching section 8,
Although the count values of the first counter 3 and the second counter 5 are selectively displayed, each of the counters 3 and 5 is provided with an independent display section, and the count values of the counters 3 and 5 are displayed. If configured to display both at the same time, there is no need for a switching operation in the switching unit 8, and work efficiency is further improved.

Further, the absolute origin in one machining operation is generally often taken at the reference plane of the workpiece. Therefore, for example, if the first reset circuit 4 is activated by the output signal of a reference surface detection device that detects the contact between the tool (touch sensor) and the reference surface of the workpiece and sets the reference surface. , it becomes possible to perform the resetting operation of the first counter 3 reliably, accurately, and easily.

Furthermore, for example, when cutting a workpiece whose total length L to be cut is known, the second counter 5 counts the cutting amount, and the first counter 3 counts the remaining amount. It is also possible to switch between the cutting amount and the remaining amount.

That is, as shown in Fig. 3, if the workpiece moves from the right to the left in the figure during machining, first the right end of the workpiece is brought into contact with the cutting tool and this point is set as the absolute origin. After the first reset circuit 4 is activated and the count value of the first counter 3 is set to 0, the workpiece is moved to the right, the left end of the workpiece is positioned at the cutting tool position, and the second reset circuit 4 is activated. The circuit 6 is activated and the count value of the second counter 5 is set to zero. When the cutting operation is performed after that, the value displayed on the second counter 5 becomes the cutting amount _L4 , and the absolute value of the value displayed on the first counter 3 becomes the remaining amount _L5 .

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

As mentioned above, the length measuring device according to the present invention is
a direction determining circuit that detects the phase of the pulse signal output from the scale section to determine the moving direction of the reference scale; and first and second circuits that individually count the pulse signals according to the output signal of the direction determining circuit. 2
a counter, a reference surface detection device that detects contact between the sensor and the reference surface of the workpiece and outputs a detection signal; a first reset circuit that resets the first counter in response to the detection signal; The device comprises a second reset circuit for resetting the second counter at any time, and a display section for displaying the contents of the first and second counters.

Therefore, one counter can be set to the reference plane of the workpiece as the absolute origin, and the other counter can be used to perform length measurement operations from the machining origin, which can be set arbitrarily depending on the machining circumstances. Therefore, it is possible to know the amount of movement from the absolute origin as needed during machining, and it is also possible to accurately return to the absolute origin position no matter where the machining origin is set, making machining work extremely easy. In addition, since no calculation means are required, processing and positioning work can be performed quickly, and the effect of improving work efficiency is extremely large. Further, since the absolute origin is set by detecting the contact between the processing reference surface of the workpiece and the sensor using the reference surface detection device, the absolute origin can be easily set.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of a length measuring device according to the present invention, and FIGS. 2 and 3 are diagrams for explaining measurement operations according to the embodiment. 1...Scale section, 2...Direction discrimination circuit, 3...
...first counter, 4...first reset circuit,
5...Second counter, 6...Second reset circuit, 7...Display section.

Claims (1)

[Scope of utility model registration request] Equipped with a scale section that optically or magnetically reads the amount of movement of a reference scale mounted on the movable member side using an encoder mounted on the fixed member side,
In a length measuring device that measures the movement direction and movement amount of the reference scale based on the phase and number of pulse signals output from the scale section, the movement direction of the reference scale is determined by detecting the phase of the pulse signal. a direction discrimination circuit for discriminating; first and second counters for individually counting the pulse signals according to the output signal of the direction discrimination circuit; and detecting contact between the reference surface of the workpiece and the sensor to generate a detection signal. a first reset circuit that resets the first counter in response to the detection signal; a second reset circuit that resets the second counter at any time; 1. A length measuring device comprising a display section that displays the contents of a second counter.