Apparatus for measuring coefficient of restitution and hardness tester

A hardness tester, comprising:

• a holder for holding a spherical indenter;
• an ejection mechanism configured to eject the indenter held by the holder from the holder to a specimen;
• a speed measuring unit configured to measure an impact speed that is a speed of the indenter before the indenter impacts against the specimen, and a rebound speed that is a speed of the indenter after the indenter is rebounded from the specimen;
• and
• an arithmetic unit configured to decide hardness of the specimen based on a ratio of the rebound speed to the impact speed,
• wherein the holder has a front end constituted by a plurality of divided portions which are configured to hold a circumferential surface of the indenter.

The apparatus for measuring coefficient of restitution, comprising:

• a holder for holding a spherical indenter;
• an ejection mechanism configured to eject the indenter held by the holder from the holder to a specimen;
• a speed measuring unit configured to measure an impact speed that is a speed of the indenter before the indenter impacts against the specimen, and a rebound speed that is a speed of the indenter after the indenter is rebounded from the specimen;
• and
• an arithmetic unit configured to calculate a coefficient of restitution that is a ration of the rebound speed to the impact speed,
• wherein the ejection mechanism includes:
• an inner cylinder with a through hole formed therein,
• an outer cylinder having an inner circumferential surface slidably supported by an outer circumferential surface of the inner cylinder,
• an indenter pushing member movable in the through hole, and
• a biasing spring disposed between the outer cylinder and the indenter pushing member, the biasing spring being compressed by movement of the outer cylinder to apply a biasing force to the indenter pushing member, and
• wherein the outer cylinder has an ejection lever configured to engage with a groove formed on an outer surface of the indenter pushing member.

A hardness tester, comprising:

• a holder for holding a spherical indenter;
• an ejection mechanism configured to eject the indenter held by the holder from the holder to specimen;
• a speed measuring unit configured to measure an impact speed that is a speed of the indenter before the indenter impacts against the specimen, and a rebound speed that is a speed of the indenter after the indenter is rebounded from the specimen;
• and
• an arithmetic unit configured to decide hardness of the specimen based on a ration of the rebound speed to the impact speed,
• wherein the ejection mechanism includes:
• an inner cylinder with a through hole formed therein,
• an outer cylinder having an inner circumferential surface slidably supported by an outer circumferential surface of the inner cylinder,
• an indenter pushing member movable in the through hole, and
• a biasing spring disposed between the outer cylinder and the indenter pushing member, the biasing spring being compressed by movement of the outer cylinder to apply a biasing force to the indenter pushing member, and
• wherein the outer cylinder has an ejection lever configured to engage with a groove formed on an outer surface of the indenter pushing member.