| 主权项 |
1. A viscous material container comprising:
a housing comprising:
a first section having an insertion port at an end thereof and including a first inner wail surface configured to surround a first passage extending along a first imaginary center line from the insertion port and having a transverse sectional shape that is circular about the first imaginary center line;a second section having a discharge port at an end thereof and including a second inner wall surface configured to surround a second passage extending along a second imaginary center line from the discharge port and having a transverse sectional shape that is circular about the second imaginary center line, the second imaginary center line intersecting the first imaginary center line; anda third section positioned between the first section and the second section and including a third inner wall surface configured to surround a third passage communicating with the first passage and the second passage; and a piston operable to move inside at least the first passage to push out a viscous material, which is contained in at least the first passage, from the discharge port through the second and third passages, the piston comprising:
one annularly circular contact portion configured to contact the first inner wall surface as the piston is inserted in the first passage, and a pair of non-contact portions configured not to contact the first inner wall surface as the piston is inserted in the first passage, located at both sides of the annularly circular contact portion in a direction of extension of the first imaginary center line and having an outside diameter that is smaller than that of the annularly circular contact portion; the pair of non-contact portions being shaped to be plane-symmetric with respect to a first imaginary surface that includes the annularly circular contact portion and is orthogonal to the first imaginary center line, wherein: the first section of the housing is formed with at least one groove portion communicating with the first passage to discharge air inside the first passage when the piston is inserted from the insertion port; the at least one groove portion communicates with the insertion port, and extends along the first imaginary center line; and a length of the at least one groove portion along the first imaginary center line and a length of the non-contact portions are determined such that air inside the housing is discharged out of the housing through the at least one groove portion until the piston is inserted into the first passage to the extent that the annularly circular contact portion goes beyond the at least one groove portion. |
