JPH0545959Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a comparative tester for the impact resistance of hard contact lenses or materials for hard contact lenses. The present invention relates to an impact resistance comparison tester for hard contact lenses and their materials, which enables comparative measurements of hard contact lenses and their materials.

[Conventional technology]

Conventionally, hard contact lenses use PMMA (polymethyl methacrylate) as a material, and various physical properties of the material, such as specific gravity, refractive index, light transmittance, water absorption, and oxygen permeability coefficient, have been measured and displayed. but,
Since PMMA is widely used as an organic glass, its mechanical properties rely heavily on existing data and were not measured and displayed.

In recent years, various hard contact lenses with improved oxygen permeability have been developed in place of PMMA and are beginning to take root in the market. These are called oxygen-permeable hard contact lenses, which reduce the supply of oxygen to the cornea.
Because it is superior to PMMA hard contact lenses, it is a highly safe contact lens that is less prone to various disorders caused by oxygen deficiency in the cornea. However, as oxygen permeability improves, mechanical strength tends to decrease. It is expected that oxygen permeability will further improve in the future, and the measurement and evaluation of mechanical strength will have important implications for the development of materials and the evaluation of contact lenses.

Currently, as mechanical properties, surface scratch hardness is measured as abrasion resistance in material evaluation, and various indentation hardness or stiffness are measured as physical properties related to breaking strength, but impact force generated when handling contact lenses is measured. Currently, there is no established method for evaluating the resistance of contact lenses to

Conventionally, contact lens materials have also been evaluated using an off-the-shelf hammer type impact tester. (Refer to JIS K 7111.) This testing machine is equipped with a hammer and a positioning needle, and is intended for testing general hard plastics. In such a test machine,
The specified dimensions of the test piece are much larger than those of the contact lens, and the hammer used is also heavy.

However, if this tester is used as is for contact lenses, the weight of the hammer is too large relative to the contact lenses, so the difference in mechanical strength of the contact lenses will not be reflected in the measurement results.
Therefore, in order to comparatively evaluate the impact resistance of contact lenses, it is necessary to reduce the weight of the hammer in accordance with the contact lenses.

However, if the hammer is made small enough to allow comparative evaluation of the impact resistance of contact lenses, a new problem arises in that the hammer that has destroyed the contact lens cannot move the positioning needle. The reason for this problem is that the weight of the hammer is originally small, and in the testing machine mentioned above, it is necessary to convert the kinetic energy of the hammer that broke the contact lens into the kinetic energy of the positioning needle. This is because a large amount of energy is lost during this process.

The above-mentioned testing machine had a problem in that it was not possible to accurately compare and evaluate the impact resistance of contact lenses.

Furthermore, even when following the prescribed measuring method of the above-mentioned tester, it is necessary to take the trouble to prepare large-sized test pieces of the same material that makes up the contact lens, and the impact resistance of the contact lens itself is There was a problem that it was not possible to compare and evaluate gender.

[The problem that the idea attempts to solve]

In view of the above-mentioned facts of the prior art, the inventors of the present invention have worked diligently to complete the present invention.

That is, the purpose of the present invention is to newly devise and provide a device capable of comparatively evaluating impact resistance using hard contact lenses or materials thereof as test pieces.

[Means to solve the problem]

The present invention has been made to achieve the above object, and includes a rotary bearing having a rotary shaft that can rotate in only one direction, one end of which is attached to the rotary shaft of the rotary bearing, and the other end of which is a hard contact. A striking mallet that is rotatably held around the axis of rotation and serves as an angle indicator, which strikes a test piece made of a lens or its material by rotating and dropping; and a scale for measuring the swing angle of the striking mallet. This is an impact resistance comparative testing machine characterized by comprising: a board; and a test piece holding stand for holding the test piece.

[Effect]

According to the impact resistance comparison tester of the present invention, a rotary bearing having a rotary shaft that can rotate in only one direction is used, and the hammer attached to this rotary shaft also serves as an indicator needle, so contact lenses The kinetic energy of the hammer that destroyed the needle becomes the kinetic energy of the indicator needle, and there is no energy loss that occurs in conventional testing machines. Further, since the rotating shaft can only rotate in one direction, the hammer attached to the rotating shaft stops at the highest point of swinging and does not move backward.

〔Example〕

FIG. 1 is a front view of an impact resistance comparison tester according to an embodiment of the present invention, and FIG. 2 is a side view thereof.
Hereinafter, one embodiment of the present invention will be described in detail with reference to these drawings.

In the figure, numeral 1 is a pedestal, numeral 2 is a column installed on the pedestal 1, numeral 3 is a scale plate attached to the pedestal 2, and numeral 7 is a dial mounted on the pedestal 2, which can rotate in only one direction. A rotating bearing having a rotating shaft 71 (hereinafter referred to as a one-way rotating bearing), numeral 4 is a hammer whose one end is attached to the rotating shaft 71 of the one-way rotating bearing 7, and numeral 5 is a hammer mounted on the pedestal 1. x, y, z position adjustment mechanism, which is a fixed table movable in three orthogonal directions, vertically, horizontally, and vertically; reference numeral 8 denotes a test specimen holding stand attached to the x, y, z position adjustment mechanism; It is.

The pedestal 1 has feet 11 for height adjustment,...
11 is attached, and a spirit level (not shown) is also provided for checking levelness.

The pedestal 1 is provided with x,
The y,z position adjustment mechanism 5 is fixed. This x, y, z position adjustment mechanism 5 includes an x direction (horizontal) position adjustment section 51, a y direction (vertical) position adjustment section 52, and a z direction (horizontal) position adjustment section 51.
It is composed of a direction (height) position adjustment section 53. These x, y and z position adjustment parts 51, 52 and 53 are fixed bases 51a, 52a and 5, respectively.
Movable stands 51b, 52b, and 53b are movably attached to 3a. By operating the respective adjustment screws 51c, 52c, and 53c, the test piece holding stand 8 attached to the movable stand 53b of the z-direction position adjustment section 53 via the rotating drum 531 is adjusted in the x direction and the y direction. and the position in the z direction can be adjusted. In addition,
The rotating drum 531 is connected to the z-direction position adjustment section 5.
It is rotatably attached to a holding frame 532 fixed to a movable base 53b of No. 3, and can be fixed with a fixing screw 533.

An L fitting 534 is fixed to one end surface (the right end surface in FIG. 2) of the rotating drum 531, and a test piece holding stand 8 is fixed onto this L fitting 534.

As shown in FIG. 2, the test piece holder 8 has a substantially rectangular parallelepiped shape, and a circular hole 81 is formed in the upper portion thereof, penetrating in a direction perpendicular to the plane of the drawing.
The upper portion of the circular hole 81 is connected to the upper end surface of the test piece holder 8 to form an open groove.
The lower part of the circular hole 81 has a rectangular cross section.
A striking hammer passage groove 82 penetrating in a direction perpendicular to the plane of the drawing is formed in communication with the lower part of the circular hole 81 .
A contact lens as a test specimen can be placed on the bottom of the circular hole 81. This allows the striking hammer 4 to strike the test specimen by passing through the circular hole 81, the opening groove, and the striking hammer passage groove 82 in a direction perpendicular to the paper surface. The shape and size of the test specimen holder 8 are appropriately selected according to the shape and size of the test specimen. The material of the test specimen holder 8 can be, for example, plastic, metal, ceramics, etc.

As shown in FIGS. 1 and 2, the striking hammer 4 is preferably, for example, a substantially short flat plate, one end of which is attached to the rotation shaft 71 of the one-way rotation bearing 7. The other end is for striking the test piece. The hammer 4 is suitably made of metal such as aluminum or titanium, and is made of a relatively lightweight material with excellent mechanical strength. Further, it is preferable that the striking hammer 4 is constructed so that it can be replaced with one of various lengths at any time.
Further, the hammer 4 has a hole 41 for attaching a load at a position on its plane (a position that does not interfere with the operations of lifting, hitting, and swinging the hammer) and on the other end side. . Since this hole 41 is provided, by attaching a load such as a weight to various positions of this hole 41, the impact impact force on the test piece can be adjusted. When using a hammer with such a structure, the impact energy due to the impact is controlled by the length of the hammer 4, the load weight (size of the load), the load attachment position, and the lowering position (holding position) of the hammer 4. upper angle).

The support column 2 is a substantially rectangular plate-like body made of aluminum or the like, and its lower portion is vertically fixed to the pedestal 1 by a fixing fitting 21.

The one-way rotation bearing 7 is fixed to the upper part of the support column 2. In this case, the one-way rotation bearing 7
The rotating shaft 71 of the hammer is horizontal, and the other end of the hammer 4, which has one end vertically fixed to the shaft 71, can be adjusted so that it can pass through the circular hole 81 of the specimen holding table 8. fixed in position. That is, when the striking mallet 4 is rotated around the rotating shaft 71 of the one-way rotation bearing 7, the other end of the striking mallet 4 is rotated around the circular hole 81 of the test piece holding table 8.
It is designed so that the position can be adjusted so that the test piece placed on the can be struck. Note that this adjustment is performed by the x, y, z position adjustment mechanism 5. Furthermore, the rotary shaft 71 may be one that is well known in the art, for example, "NSK One-Way Clutch" (published in July 1984) in the catalog published by NSK Ltd.
You can use the one-way clutch, ratchet, etc. described in In particular, one-way clutches are known to have a small coefficient of rotational friction.

The one-way rotation bearing 7 is mounted on the upper part of the support column 2.
A disc-shaped scale plate 3 is installed behind the unidirectional rotary bearing 7 perpendicularly to the rotating shaft 71 and parallel to the hammer 4.
is installed. Further, the scale provided on the scale plate 3 is formed in a circumferential shape as shown in FIG. Further, the scale plate 3 is attached so that the center of the circumferential scale and the center of the rotating shaft 71 substantially coincide with each other. The scale plate 3 is a hammer 4
It is used to measure the stopping position (the position where the hammer 4 is lifted and the position where the hammer 4 is swung up) in terms of angles (lifting angle and swinging angle, respectively), and is usually equipped with a protractor scale. used.

According to the impact resistance comparison tester of the above embodiment, the test can be conducted as follows.

First, as a test piece, for example, a hard contact lens material is processed into a disk with an outer diameter of 8 to 10 mm and a thickness of 0.1 to 1 mm, and the surface and periphery are smoothed, or a hard contact lens is prepared. The test piece is placed at a predetermined position on the test piece holding table 8.

Next, the position of the test piece holding table 8 is changed to the x,
Adjustments are made using the y and z position adjustment mechanism 5, and the other end of the striking hammer 4 is set so that it can strike a desired striking point on the test piece.

Next, rotate and lift the hammer 4 by hand,
It is held in a predetermined position (predetermined lifting angle) with a pin (not shown).

Thereafter, the pin is removed and the striking hammer 4 is allowed to rotate and fall naturally.

As a result, the striking hammer 4 falls while rotating around the rotating shaft 71 of the one-way rotating bearing 7, and after striking and breaking the test piece, it swings to the opposite side by an amount equivalent to the remaining energy due to inertia and stops. do.

This stop position is determined by the angle (swing-up angle) from the position of the specimen holding table 8 using the scale of the scale plate 3.
Read by.

Impact resistance can be compared by repeatedly measuring under the same conditions as the control sample or comparative sample as described above. The larger the energy required to break the test piece, that is, the larger the impact strength, the smaller the swing-up angle. Therefore, it can be said that the smaller the value of the swing-up angle, the higher the impact resistance. This value does not represent an absolute value of impact resistance, but is merely a relative value compared with others.

The embodiment described above has the following advantages.

In other words, a rotating bearing with a rotating shaft that can rotate in only one direction was used without using a positioning needle, and since the striking mallet attached to this rotating shaft also served as an indicator needle, the movement of the striking mallet that broke the contact lens. The energy directly becomes the kinetic energy of the indicator needle, and there is no energy loss that occurs in conventional testing machines. Therefore, it is possible to comparatively evaluate the impact resistance of light and small test pieces such as contact lenses.

Furthermore, since it is equipped with an x, y, z position adjustment mechanism and a rotating drum, it is possible to freely move the test piece holding table. Therefore, the impact resistance can be comparatively evaluated by setting the impact position and impact direction on the test piece to a desired position and direction.

[Effect of idea]

According to the impact resistance comparison tester of the present invention, it is possible to comparatively evaluate the impact resistance not only of contact lens materials but also of hard contact lenses themselves.

Therefore, the impact resistance comparison tester of the present invention is useful for evaluating commercially available hard contact lenses or for quality control in contact lens manufacturing, and is useful for developing contact lens materials and designs due to differences in material and shape. This is useful for evaluating and improving impact resistance.

[Brief explanation of drawings]

FIG. 1 is a front view of an impact resistance comparison tester according to an embodiment of the present invention, and FIG. 2 is a side view of the embodiment. 1... Pedestal, 2... Support, 3... Dial plate, 4...
...Blow hammer, 5...x, y, z position adjustment mechanism, 7...
...Rotating bearing having a rotating shaft that can rotate in only one direction, 8... Test specimen holding stand, 41... Hole for attaching a load.

Claims (1)

[Claims for Utility Model Registration] (1) A rotating bearing having a rotating shaft that can rotate in only one direction, one end of which is attached to the rotating shaft of the rotating bearing, and the other end of which is made of a hard contact lens or its material. A striking mallet, which also serves as an angle indicator and is rotatably held around the rotating shaft and which strikes the test piece by rotating and dropping it; a scale plate for measuring the swing angle of the striking mallet; and the test piece. An impact resistance comparative testing machine characterized by comprising a test piece holding stand for holding a test piece. (2) The impact resistance comparison tester according to claim 1, wherein the hammer is a flat plate made of metal and can be replaced with a hammer of a different length. (3) Claim 1 for Utility Model Registration: The hammer is a hammer that has a hole for attaching a load and can adjust the impact force by changing the load and/or the load attachment position. term or second
Impact resistance comparison tester described in section.