JPH0434301A - Length measuring apparatus - Google Patents

Abstract

PURPOSE:To prevent infiltration of dust, water drops, steam oil mist and the like into a housing by covering a gap generated by raking a seal member to cut the inside of the housing off the outside thereof. CONSTITUTION:Air is discharged from a discharge port 29 of an air feed pipe 25 to form an air curtain outside a seal member 5 at an opening 9 of a housing 4. In this manner, an air type closing function of an air type closing means works to shield dust, water drops, steam and oil mist light relatively to be kept from moving into the housing 4. In addition, dust, water drops, steam, oil mist and the like that are so heavy to pass the air curtain are so large in volume accordingly that they will find no chance to pass through gaps generated at a tip block 14 of the seal member 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a length measuring device that measures the distance traveled by relative movement of a main scale installed in a housing and a detection head. In particular, the present invention relates to an improvement in a length measuring device equipped with a dust-proof and liquid-proof seal member to prevent dust, water droplets, water vapor, oil mist, etc. from entering the housing through an opening formed in the housing.

[Prior Art] As shown in FIG. 5, a conventional length measuring device 1b has a connecting member 7b inserted through an opening 9b of a housing 4b, and a connecting member 7b inserted through an opening 9b of a housing 4b.
A sealing member 5b was disposed near the opening 9b to close the opening 9b.

[Problems to be Solved by the Invention] In the conventional length measuring device 1b, the clearance of the connecting member 7b is
When the seal member 5b is scraped by the seal member 9b, a scraping gap (not shown) is generated at the distal end portion 14b of the seal member 5b.

For this reason, dust, water droplets, water vapor, oil mist, etc. can enter the housing 4b through the clearance gap, and as a result, the length measurement detection value may be affected, or the main scale 2
There was a problem in that the length measurement detection means such as the detection head 3b and the detection head 3b were damaged.

This invention was made in view of the above circumstances,
A sealing member for closing the opening of the housing is provided, and even if a gap is created between the abutting tips of the sealing member by the connecting member, the gap is substantially closed to provide higher dust-proof and liquid-proof effects, Therefore, it is an object of the present invention to provide a length measuring device which is less affected by measurement detection results and whose length measurement detecting means is less likely to be damaged.

[Means for Solving the Problems] The present invention provides that when the connecting member that connects the detection head to the object to be measured scrapes the seal member, a clearance gap is created at the abutting tips of the seal member. This length measuring device is provided with a pneumatic closing means that substantially closes the gap between the members by covering it with an air curtain.

Its detailed configuration includes a main scale and a detection head that detect the distance of movement by moving relative to each other, and a main scale and a detection head that are installed inside the main scale and a detection head that detects the distance of movement by moving relative to each other. A housing having an opening, a connecting member inserted through the opening of the housing, and having one end connected to the main scale or detection head and the other end connected to the object to be measured, and a flexible material. a sealing member formed from a plurality of metallurgical units, the distal ends of which are disposed abutting each other to close the opening of the housing, and a calculation device that indicates the amount of relative movement between the main scale and the detection head based on a signal from the detection head. In addition, air is caused to flow at a position on the outside of the sealing member relative to the housing, thereby forming an air curtain to prevent the protrusion of the sealing member when the connecting member passes through the sealing member. This length measuring device is provided with a pneumatic closing means that substantially closes the gap created at the mating tip.

Here, "substantially closing the raking gap" means to prevent dust, water droplets, water vapor, oil mist, etc. from entering the housing through the raking gap.

Further, as specific means thereof, there may be a structure including a blower pipe attached to the connecting member to form the air curtain, or a blower pipe arranged along the opening of the housing. There are many things that can be mentioned.

[Function] The gap created by the connecting member between the seal members is
It is substantially occluded by a pneumatic occluder.

[Example] This invention will be explained in detail with reference to the example shown in FIGS. 1 to 4. However, the invention is not limited to this example.

As shown in FIGS. 1 and 2, the length measuring device 1 includes a main scale 2, a detection head 3, a housing 4, and a seal member 5.
, a calculation display means 6 , a connecting member 7 , and a pneumatic closing means 8 .

The main scale 2 is arranged and fixed inside the housing 4.

The housing 4 has a substantially box shape, and has an opening 9 at the bottom that extends along the fixed main scale 2.

The detection head 3 is movably disposed within the housing 4. The detection head 3 includes an index scale 10, a light emitting element 11, a light receiving element 12, a preamplifier (not shown),
and a holder 13 that holds them. The detection head 3 is movable in the longitudinal direction of the main scale 2 (in the six directions of arrows), and when moving relative to the main scale 2, it cooperates with the main scale 2 to detect the moving distance.

The seal member 5 is made of flexible synthetic resin and has a substantially box-shaped cross section. The sealing member 5 is fitted and fixed in a groove 15 provided along the inner edge of the opening 9 so that the distal end portions 14 are brought into a butt state and close the opening 9 of the housing 4 .

The calculation display means 6 receives the signal from the detection head 3 and calculates and displays the amount of relative movement between the main scale 2 and the detection head 3. The calculation display means 6 is connected to the detection head 3 by a cable 16. Calculation display means 6
The front side is an operation/display panel 17. Further, the calculation display means 6 is also configured to operate the pneumatic closing means 8.

The connecting member 7 is inserted into an opening 9 formed in the housing 3 . The connecting member 7 has one end connected to the holder 13 of the detection head 3 and the other end connected to the object to be measured (not shown), thereby controlling the movement of the object to be measured relative to the housing 4 of the detection head 3. It is something that can be conveyed to people.

Reference numeral 18 denotes a connecting part that connects with the object to be measured, and 19 denotes a neck member that pushes the seal member 5, and both parts 18 and 1
9 is integrated.

The neck portion 19 has a cylindrical shape with a substantially elliptical cross section. A through hole (not shown) is formed in the neck portion 19 for leading a lead wire (not shown) from the detection head 3 to the outside of the housing 4 and connecting it to the cable 16.

As described above, the length measuring device 1 is provided with the pneumatic closing means 8. The pneumatic blocking means 8 includes a suction filter 20
, an air blowing means consisting of an electric air compressor 21, an air tank 22, a safety valve 23, etc., and a connecting portion 31 opened at the side of the housing 4, for introducing air from the air blowing means into the housing 4. an opening (not shown), a through hole 24 provided at the bottom of the housing 4 through which air inside the housing 4 can flow to the outside of the housing 4; The air becomes an air curtain at a position outside the seal member 5 with respect to the housing 4 and covers the seal member 5, and the space between the connecting member 7 is caused by the neck portion 19 of the seal member 5.
It is composed of an air blowing pipe 25 that closes a gap formed at the tip of the housing 4 with the outside of the housing 4.

The air pipe 25 includes a rectifier plate 26 and a rectifier plate 26 for adjusting the phase of the flow of air that has passed through the through hole 24 of the housing 4.
A wind direction plate 27 is provided therein for making the air passing through the vicinity of the air curtain 6 into the air curtain state after being discharged.

Note that 28 is an air intake port, and 29 is an air discharge port. Moreover, 30 is a part from the air tank 22 to the housing 4.
It is a vibrator for sending air to the housing 4, and is connected to the housing 4 through a connecting portion 31.

The submaster device 1 is configured as described above.

Therefore, when the length measuring device 1 is used in a room where there is dust, water droplets, water vapor, oil mist such as cutting oil, etc. due to cutting and polishing, such as a processing plant, the length measuring device 1 is naturally They will be exposed to air containing water droplets, water vapor, oil mist, etc. Therefore, dust, water droplets, water vapor, oil mist, etc. may enter the housing 4 through the opening 9.

However, outside the sealing member 5 in the opening 9, air is discharged from the outlet 29 of the blast pipe 25, forming an air curtain, and the pneumatic closing function of the pneumatic closing means 8 acts, and the weight is relatively low. Even if light dust, water droplets, water vapor, oil mist, etc. try to move toward the interior of the housing 4 through the opening 9 of the housing 4, they are blocked by the air curtain and cannot advance toward the interior of the housing 4 through the air curtain. Therefore, even if there is a gap between the butt tip 14 of the seal member 5 due to the neck 19, the connection member 7 can pass through the gap to remove the relatively light dust, water droplets, etc.
Water vapor, oil mist, etc. do not enter the inside of the housing 4.

On the other hand, relatively heavy dust, water droplets, water vapor, oil mist, etc., which are extremely heavy, pass through the air curtain formed by the pneumatic closing means 8 and proceed to the inside of the housing 4 rather than the air curtain. There are cases. In this case, dust, water droplets, water vapor, oil mist, etc. that are heavy enough to pass through the air curtain have a correspondingly large volume and can pass through the gap formed at the tip 14 of the sealing member 5 at all. It doesn't happen often. Furthermore, air from the pneumatic closing means 8 is sent into the inside of the housing 4 and is in a pressurized state, making it even more difficult for dust, water droplets, water vapor, oil mist, etc. to enter the inside of the housing 4. Hard to happen. Therefore, even if dust, water droplets, water vapor, oil mist, etc. pass through the air curtain, it is highly unlikely that they will be blocked by the seal member 5 and enter the inside of the housing 4.

Therefore, even if the length measuring device 1 is exposed to air containing dust, water droplets, water vapor, oil mist, etc., the dust, water droplets, water vapor, oil mist, etc.
Water droplets, water vapor, oil mist, etc. do not get into the housing 3, and the main scale 2, index scale 10. The length measurement detection means such as the light emitting element 11, the passive element 12, and the preamplifier are not damaged, and the length measurement detection results are hardly affected at all.

A length measuring device 1a, which is a second embodiment of the present invention, will be described with reference to FIGS. 3 and 4. In the length measuring device 1a, the pneumatic closing means 8a includes a circulating air blowing means (not shown) and a connecting member 7.
The opening a is fixed to the neck portion 19a, takes in the air from the circulating air blowing means, forms an air curtain, and discharges air so as to cover the gap created at the butt tip 14a of the sealing member 5a. , an air discharger 32a which is a blowing pipe, and a scraper fixed to the neck part 19a opposite to the air discharger 32a, for sucking air from the air discharger 32a and sending it to the circulation type blowing means. It mainly consists of a wind collector 33a. Incidentally, inside the air discharge device 32a, there are fins 34a erected to regulate the flow direction of the air from the ventilation pipe 30a so as to form the above-mentioned air curtain. Furthermore, fins 35a are provided inside the air collector 33a to facilitate sending the collected air to the ventilation pipe 30a.

The ventilation pipe 30a is stopped at a connecting portion 18a of the connecting member 7a in the middle, and is further connected to a circulating air blowing means.

The length measuring device 1a is provided with two sets of seal members 5a, and the tip portions 14a are fitted and fixed in grooves 15a so as to be butted against each other in an interlocking state.

When the length measuring device 1a is used in an environment where the air contains dust, water droplets, water vapor, oil mist, etc., the clearance at the tip of the sealing member 5 caused by the neck 19a is removed by the air closing means 8a. Since the housing 4 is covered with a curtain, the dust, water droplets, water vapor, oil mist, etc. do not enter into the interior of the housing 4 through the gap between the seal members 5a.

Therefore, in the length measuring device 1a, the length measurement detection means may be damaged or
It does not occur that the length measurement detection result is affected.

feeding the pneumatic closing means 8 and 8a of the length measuring devices 1 and 1a;
The wind ability is based on the dust, water droplets, etc. contained in the air at the site of use.
Particle size and amount of water vapor, oil mist, etc., seal members 5 and 5a
It is desirable to select the appropriate one depending on the blocking ability of the material. The shape of the blast pipe 25, the shape and size of the rectifying plate 26, the direction of the wind direction plate 27, and the size of the air discharge device 32a and the size of the fins 34a of the length measuring device 1a are determined by the size of the blowing air. It is desirable to determine the amount appropriately depending on the particle size and amount of dust, water droplets, water vapor, oil mist, etc.

The air blowing means of the length measuring device 1 may use air from an air pipe installed in a factory or the like where the length measurement is performed.

Although the length measuring devices 1 and 1a use an optical detection method, they may also use a magnetic detection method.

The length measuring devices 1 and 1a have main scales 2 and 2a fixed to housings 4 and 4a, respectively. However, the detection heads 3 and 3a may be fixed to the housings 4 and 4a, respectively, and the main scales 2 and 2a may be on the movable side.

[Effects of the Invention] The present invention uses a sealing member to close the opening of the housing, and a pneumatic closing means covers the gap created by pushing the sealing member aside, thereby blocking the inside and outside of the housing. This prevents dust, water droplets, water vapor, oil mist, etc. from getting inside the housing.
Therefore, this length measuring device can prevent damage to the length measuring means and prevent any influence on the length measuring results.

25...Blow pipe, 32a... air discharge port, 29...Discharge port, 33a...Air collector.

Claims (1)

[Claims] 1. A main scale and a detection head that detect the distance of movement by moving relative to each other, and an opening is provided along the longitudinal direction of the main scale and the main scale and the detection head are installed inside the main scale and the detection head. a housing formed of a flexible material, a connecting member inserted through an opening of the housing and connected to the main scale or detection head at one end and to the object to be measured at the other end, a sealing member whose distal ends abut each other to close the opening of the housing; and a calculation display means for calculating and displaying the amount of relative movement between the main scale and the detection head based on the signal from the detection head. In addition, an air curtain is formed by flowing air at a position on the outside of the seal member relative to the housing, and air is generated at the abutting tip of the seal member when the connecting member moves through the seal member. A length measuring device provided with a pneumatic closing means for substantially closing a clearance gap.