JP4667088B2 - Bubble tube and manufacturing method thereof - Google Patents

Description

  The present invention relates to a bubble tube incorporated in a level and a manufacturing method thereof.

  The bubble tube built into the level is made up of a cylinder filled with liquid and sealed with bubbles, and an indicator line is formed on the cylinder to determine the state of the level by the bubbles. Normally, the index line is usually drawn on the outer surface of the cylinder by screen printing or hot stamping.

  By the way, in this type of bubble tube, as shown in FIG. 1, there is a difference between the position where the bubble a is present and the position where the index line L is drawn by the thickness of the cylinder. As a result, the position of the bubble could not be read accurately, and there was a problem that the measurement accuracy was lacking.

As a bubble tube for reducing parallax as described above, a narrow groove is provided on the inner side of the cylinder, and a C-shaped ring is inserted into the narrow groove to form an index line. Alternatively, a ring-shaped tube is formed on the inner side of the cylinder. There is also known a bubble tube in which a member is insert-molded to leave only a portion serving as an index line, and the index member is cut by cutting (see, for example, Patent Document 1).
US Pat. No. 5,651,186

  By the way, the bubble tube which inserts a C-shaped ring and uses this as an index line has a gap between the ring r and the groove wall m depending on the accuracy of the groove m into which the ring r is inserted, as shown in FIG. It is often unavoidable that there is a step between the inner wall surface of the cylinder and the ring, and it is often observed that the bubbles do not move smoothly. Since the ring r is inevitably rotated in the groove m due to vibration during welding work for sealing, leveling vibration during measurement work, etc., the cuts of the ring r are uneven and the appearance is poor. There was a limit in improving quality.

On the other hand, what insert-molds a ring-shaped member inside a cylinder and performs a cutting process had the following malfunctions.
a. As shown in FIG. 3, the index ring r is held by a molding die pin P having a step as shown in FIG. 3, and insert molding is performed. However, the diameter of the base portion of the pin P becomes thicker, and the cylindrical body is later cut. A round (R) cannot be attached to the inner surface of the.
b. As shown in FIG. 4, when the insert is formed, the ring r may be displaced due to the resin flow, and the pitch between the rings may be changed or the ring itself may be bent (the ring can be prevented from being bent by increasing the thickness of the ring). However, there are restrictions when you want to make the index line thinner).
c. As the number of rings r increases, the number of pins increases, which necessitates the necessary processing and increases the number of man-hours. Also, the diameter at the base of the pin increases, making it difficult to reduce the size of the bubble tube.
d. Since the rings are inserted into the pins manually one by one, as the number of rings increases, the number of parts to insert increases, which takes time during molding.
e. To change the number of rings, the pins must be changed, but this is not suitable for high-mix low-volume production that requires frequent replacement of the pins.

  An object of the present invention is to propose a novel bubble tube capable of solving the above-described conventional problems and a method for manufacturing the same.

The present invention is a bubble tube comprising a cylinder having an index on the inner wall surface and filling a liquid with bubbles,
The indicator is formed by molding the cylindrical body with respect to an outer surface of a sleeve having at least one of a disk, a ring, a fin, a character, a symbol, or a number, and the disk, the ring, the fin, the character, It is a bubble tube characterized by being formed by cutting the sleeve while leaving a symbol or a number .

  In the bubble tube configured as described above, at least one of an annular line, a character, a symbol, or a number can be provided as the indicator.

Further, the present invention has an index on the inner wall, and in producing a bubble tube composed of a cylindrical body that fills liquid with bubbles,
A sleeve having at least one of a disk, a letter, a symbol, or a number is prepared on the outer surface of the main body, and first, double molding is performed to form a cylindrical body on the outer surface, and then the disk, the letter, the symbol, or A method of manufacturing a bubble tube, characterized in that a cutting process is performed to cut out the main body of the sleeve while leaving a numeral.

  Since the disk (characters used as the index line), characters, symbols, numbers, etc., which are used as indicators, are molded into the sleeve in advance, the molding process is simplified, and discs, characters, symbols, numbers, etc. There will be no deformation such as displacement of the arrangement interval or falling down.

  After the double molding, the sleeve main body is removed by cutting, so that the inside of the bubble tube is smooth and the bubbles move smoothly.

  Since the index line does not form a cut, it not only looks good, but the sleeve diameter can be set relatively freely, so there are no restrictions when rounding the inner surface, and the bubble tube can be downsized. Become

  When the index line is formed, the rising amount of the ring can be reduced by adjusting the diameter of the sleeve. Therefore, even when the ring is thin, it is possible to suppress deformation during double molding. Furthermore, the shape of the blade used for cutting can be simplified.

Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 5 is an external perspective view of a bubble tube according to the present invention in which four index lines are provided.

  In the figure, 1 is a cylinder, 2 is an index line provided on the inner wall surface of the cylinder, and 3 is a bubble formed by a liquid filled in the cylinder 1.

  The above-mentioned bubble tube is incorporated in a level, and the level of the level is grasped by observing where the bubble 3 is in relation to the index line 2.

  In order to manufacture such a bubble tube, a sleeve S integrally including a ring as shown in FIG. 6 is formed. Then, as shown in FIGS. 7 and 8, the cylindrical body 1 is formed of a transparent resin on the outside of the sleeve S by double molding (insert molding or the like), and then a part of the ring is left as shown in FIG. After cutting the main body of the sleeve S as it is, the inside is filled with a liquid and sealed with a separately prepared lid.

FIG. 10 shows the appearance of the sleeve S having a disk capable of forming two index lines, and FIG. 11 shows the appearance of the sleeve S having a disk capable of forming six index lines. .

  In order to simplify the manufacturing process, at least one of the end surfaces of the sleeve S is closed so that a lid can be integrally formed. However, as shown in FIG. The sleeve S can also be used.

  Furthermore, the inner side of the sleeve S can be changed to a shape other than a perfect circle as shown in FIGS. 13A to 13E, and a key-like convex portion or a key groove-like concave portion can be provided, This is not a limitation.

  In particular, when it is necessary to form the index line in a broken line shape as shown in FIG. 14, a plurality of fins f as shown in FIGS. 15 (a) and 15 (b) are provided on the outer surface of the sleeve S. Can be easily handled.

  For example, when it is desired to display numbers, letters, symbols, etc. along with the index line, numbers, letters, symbols, etc. may be formed on the sleeve S together with the ring.

  FIG. 16 shows an example in which numbers are provided together with index lines, and FIG. 17 shows an example in which characters are provided together with index lines. In particular, when a character is provided, a reverse character is formed on the sleeve S, and the sleeve S is incorporated in the level so that it becomes the bottom of the bubble tube.

  FIG. 18 shows the cutting edge of a cutting tool used for manufacturing a bubble tube according to the conventional method. In cutting using such a cutting tool (bite), only the inner surface processing of a cylindrical body is performed. However, it was necessary to form a narrow groove and the cutting work required a lot of labor, but in the present invention, it is possible to use a blade having a blade edge as shown in FIG. Machining can be completed by feeding the cutting edge once.

  A bubble tube with improved quality can be provided at low cost without being affected by parallax.

It is a figure showing the state where parallax occurs. It is the figure which expanded and showed the cross section of the principal part of the conventional bubble tube. It is explanatory drawing of the manufacturing point of the conventional bubble tube. It is the figure which showed the relationship between the flow of the resin at the time of manufacturing a bubble tube by a conventional system, and a ring. 1 is an external perspective view of a bubble tube according to the present invention. It is the figure which showed the cross section of the sleeve provided with the ring. It is sectional drawing just after double shaping | molding. FIG. 8 is an external perspective view of FIG. 7. It is the figure which showed the state which gave the cutting process and finished in the cylinder of the bubble tube. It is an external appearance perspective view of the sleeve which can be used for manufacture of the bubble tube of this invention. It is an external appearance perspective view of the sleeve which can be used for manufacture of the bubble tube of this invention. It is sectional drawing of the sleeve which can be used for manufacture of the bubble tube of this invention. (A)-(e) is sectional drawing of the sleeve used for manufacture of the bubble tube of this invention. 1 is an external perspective view of a bubble tube according to the present invention. (A), (b) is the figure which showed the cross section and external appearance of the sleeve used for manufacture of the bubble pipe | tube shown in FIG. It is a principal part enlarged view of the bubble tube according to this invention which provided the number with the parameter | index. It is the figure which showed the bubble tube according to this invention which provided the character with the parameter | index. It is the figure which showed the blade edge | tip of the blade for cutting used when manufacturing a bubble tube according to the conventional method. It is the figure which showed the blade edge | tip of the blade for cutting suitable for use when manufacturing the bubble tube according to this invention.

Explanation of symbols

1 Cylinder 2 Index line 3 Bubble

Claims (2)

A bubble tube made of a cylinder having an index on the inner wall surface and filled with liquid with bubbles,
The indicator is formed by molding the cylindrical body with respect to an outer surface of a sleeve having at least one of a disk, a ring, a fin, a character, a symbol, or a number, and the disk, the ring, the fin, the character, A bubble tube formed by performing a cutting process of cutting the sleeve while leaving a symbol or a number . In producing a bubble tube made of a cylinder that has an index on the inner wall and fills the liquid with bubbles,
A sleeve having at least one of a disk, a letter, a symbol, or a number is prepared on the outer surface of the main body, and first, double molding is performed to form a cylindrical body on the outer surface, and then the disk, the letter, the symbol, or A method for manufacturing a bubble tube, comprising: cutting a main body of the sleeve while leaving a numeral.

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