Measuring and testing – Hardness – By penetrator or indentor
Reexamination Certificate
1999-04-16
2002-01-08
Williams, Hezron (Department: 2856)
Measuring and testing
Hardness
By penetrator or indentor
C073S081000
Reexamination Certificate
active
06336359
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an impression forming mechanism which is used for a testing apparatus for evaluating material characteristics of a sample by applying force to the surface of the sample with an indentor in order to form an impression thereon and a hardness testing apparatus comprising the above-described the impression forming mechanism.
2. Description of the Related Art
There is a hardness testing apparatus for evaluating material characteristics of a sample by applying force to the surface of the sample with an indentor in order to form an impression thereon.
FIG. 7
shows a force applying mechanism which is used for the above-described hardness testing apparatus.
In
FIG. 7
, a hardness testing apparatus
200
which is a so-called Rockwell hardness testing apparatus, comprises an impression forming mechanism
210
comprising weights
201
, a loading arm
202
, a cam
203
, a force shaft
204
, an indentor shaft
205
, an indentor
206
, or the like.
In the impression forming mechanism
210
, the weights
201
having a predetermined weight are hung from an end of the loading arm
202
. The end of the loading arm
202
moves down by the rotation of the cam
203
. A predetermined force is applied to the force shaft
204
. The force applied to the force shaft
204
is transmitted to the indentor
206
through the indentor shaft
205
. An impression is formed on a sample mounted on a sample mounting member
207
by moving down the indentor
206
.
A force applying control of the above force applying mechanism is carried out by hanging the weights
201
having a predetermined weight from the loading arm
202
.
Further, a force applying control, for example, disclosed in the U.S. Pat. No. 5,616,857, is known. A force applied to a sample is measured by a load cell disposed on the axis which is the same as that of an indentor. The force applying control is carried out so that an actual force measured by the load cell will approximate to a set force on the basis of result of comparing the actual force data with the set force data.
Recently, it is necessary that measuring instruments and apparatus including the above-described hardness test apparatus should be small.
However, in the above-described hardness test apparatus, the loading arm
202
is disposed apart from the indentor
206
. Because the principal part of the impression forming mechanism is disposed in the position which is higher than that of the indentor
206
, there is a problem that the hardness testing apparatus is so difficult to be small in the height direction.
Further, in the force applying control carried out by using weights, there is a problem that it cannot be confirmed whether the force having a set value is applied to a sample while an impression is formed on the surface of the sample.
In the case of the force applying control carried out by using the load cell, although the force for forming an impression can be set to the set value approximately, the load cell is strained by applying the force thereto. As a result, there is a problem that a measurement error is caused in proportion to an amount of the strain. Because the load cell is precious relatively, a force applying mechanism which can carry out the force applying control cheaper and more precisely is required.
SUMMARY OF THE INVENTION
In order to solve the above-described problems, an object of the present invention is to provide an impression forming mechanism which can easily make a testing apparatus be small in a height direction and a hardness testing apparatus which is made to be small.
Another object of the present invention is to provide an impression forming mechanism which can carry out a force applying control cheaper and more precisely and a hardness testing apparatus which can carry out a force applying control cheaper and more precisely.
That is, in accordance with one aspect of the present invention, the impression forming mechanism which is used for a testing apparatus for measuring material characteristics of a sample by forming an impression with an indentor on a surface of the sample, comprises; a body part, an arm which is supported by the body part so as to be movable rotationally, for attaching the indentor to a free end portion thereof, and an arm rotating force applying part for applying a force to the arm in order to move a free end side of the arm rotationally and in order to apply a pressing force for forming an impression on the surface of the sample, wherein the arm rotating force applying part is attached to the body part below the arm.
According to the present invention, because the arm rotating force applying part for moving the free end side of the arm rotationally is disposed to the body part below the arm and the indentor is attached to the arm directly, the structure of the parts disposed above the indentor can be more simple than that of the mechanism in which the arm is disposed apart from the indentor and in which a part for operating the arm is disposed between them, according to the earlier development. The impression forming mechanism can make a testing apparatus be small in a height direction by attaching the impression forming mechanism to a hardness testing apparatus.
For example, the testing apparatus for measuring material characteristics of a sample by forming an impression with an indentor on a surface of the sample is a hardness testing apparatus for measuring a hardness of a sample, a testing apparatus for measuring an electric resistance of a sample when an impression is formed on the surf ace of the sample or the like. However, the testing apparatus is not limited to them. The all of apparatuses having an impression forming mechanism are included.
For example, the arm rotating force applying part is a motor for moving the arm rotationally by moving up and down a ball screw, a hydraulic device or a pneumatic one for moving the arm rotationally by moving up and down a piston, or the like. However, the arm rotating force applying part is not limited to them. Any device which can move the arm rotationally, may be used.
The impression forming mechanism may further comprise a rotating force transmitting member for transmitting the force generated by the arm rotating force applying part to the arm as a rotating force.
According to the present invention, in particular, the force generated by the arm rotating force applying part can be transmitted to the arm as a rotating force by the rotating force transmitting member completely.
For example, the arm rotating force applying part may be a rigid body or an elastic body like a plate spring.
The body part may contain a part of the arm rotating force applying part.
Because a part of the arm rotating force applying part is contained in the body part, the impression forming mechanism can be small.
The impression forming mechanism may further comprise an electric operating member, wherein the arm rotating force applying part applies a rotating force to the arm by operating the electric operating member.
Because the electric operating member applies the rotating force to the arm, the rotational movement of the arm can be controlled more precisely than the movement of the arm, which is carried out by weights and cam mechanism according to the earlier development.
In accordance with another aspect of the present invention, the impression forming mechanism which is used for a testing apparatus for measuring material characteristics of a sample by forming an impression with an indentor on a surface of the sample, comprises; a force applying part for applying a force in order to apply a pressing force for forming an impression on the surface of the sample to the indentor, a force transmitting member for transmitting the force applied by the force applying part to the indentor, which is deformed elastically by the force applied by the force applying part, a deformation measuring unit for measuring an amount of an elastic deformation of the force transmitting member by setting a predetermined reference po
Iida Takeaki
Kawazoe Masaru
Minami Yuichi
Oda Mitsuru
Akashi Corporation
Fayyaz Nashmiya
Williams Hezron
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