JPH0238213B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In certain eye diseases, particularly glaucoma, it is desirable to measure the pressure inside the visual organ, and an instrument for this purpose is called a tonometer. This technology is well known and instruments based on several different principles have already been proposed.

This invention is an improvement on the conventional flattening tonometer whose features are described in Japanese Patent Publication No. 8164/1983, which further refers to British Patent No. 862,920.

The above-mentioned Japanese Patent Publication No. 55-8164 describes a configuration in which a flattening member is attached to an arm connected to a manual adjustment knob via a helical spring. This manual adjustment knob is calibrated to create a spring tension when the required pressure is applied to the eye by the flattening member.

A major drawback of this conventional arrangement is that the rotational displacement of the flattening member either winds up or unwinds the spring, so that the scale reading is correct only in only one rotational position of the pivoting member. That means no. Therefore, the disadvantage is that due to the difference in the position of the applanation member when measuring pressure and when setting the scale, small errors occur when evaluating the force actually acting at the moment of pressure measurement. It was hot. To explain in more detail with reference to FIG. 6, the finger wheel O applies a force (Z) to one end of the main spring L. The other end of the main spring L is fixed to a lever H carrying a flattening member J. The compensation spring M is connected between the finger wheel and the anchor plate G fixed to the main body. The scale P' is read by a pointing line which moves with the finger wheel O. The compensation spring M in such a tonometer of Japanese Patent Publication No. 55-8164 is provided to reduce nonlinearity in the operation of the main spring L, but the basic operation of the compensation spring M is that of a balance spring (i.e., to maintain balance). (spring), that is, the main spring L
As the deformation of the compensating spring M increases, the deformation of the compensation spring M tends to decrease. This caused the above-mentioned drawbacks.

The purpose of the invention is to improve the drawbacks of the prior art described above.

The flattening tonometer of the present invention includes a main body carrying a flattening member mounted on a rotatably provided arm, and a manually adjustable member that applies rotational force to the flattening member via a coil spring member. and a measuring device for measuring the force applied to the flattening member as the coil spring member deforms, the force being applied to the flattening tonometer by two coil springs in series with each other. each outer end of the spring is connected to the manually adjustable member and the arm respectively, both inner ends of the spring are fixed to a central spindle, and the measuring device rotates with the spindle. Equipped with a scale, the arm is equipped with an instruction mark,
The indicator mark is characterized in that it defines the angular position of the arm with respect to the body and/or with respect to the scale of the spindle.

That is, in the flattening tonometer of the present invention, as shown in FIG. 5, force ( Z) is applied to one end of a spring or coil spring G, the other end of this spring G is fixed to a spindle D (and scale L), and the force (Z) is transmitted to a spring H via the spindle, and the spring or coil The other end of the spring H is the arm A and the flattening member B.
act on and rotate it. The scale L is read with respect to a reference line B fixed to the main body. Therefore, in the present invention (unlike the case of Japanese Patent Publication No. 55-8164), both springs G and H operate so that the deformation increases or decreases. The present invention
It has been found that this configuration of the present invention allows the spring to operate in a more linear state.

Embodiments of the present invention will be described below with reference to the drawings. Arm A carries a flattening member B within the body of the tonometer. This flattening member B is
It can be similar in shape and function to the flattening member of the tonometer shown in Publication No. 8164, and this publication can also be referred to for details.
Arm A is mounted on a low friction bearing C. This low-friction bearing C rotates around a spindle rotatably attached to low-friction bearings M and N. Bearing M
is directly supported by a frame E fixed to the body of the tonometer. Bearing N is supported by anchor wheel F.

Anchor wheel F carries an anchor for the outer end of spring G. The inner end of the spring G is connected by an end cap K and a scale disc L.
It is fixed in a slotted hole at one end of spindle D. The inner end of a further coil spring H is fixed in a slotted hole at the other end of the spindle D by a similar end cap and scale disc L'. The outer end of the spring H is fixed to a protrusion P on the arm A. This arm A has two more
It carries two projections Q and R which project oppositely to each other and project oppositely to each other with respect to the axis of the bearing C. Each of the protrusions Q, R is provided with an indicator line which coincides with the respective graduation disc L, L'. Scale disk L,
L' is visible from both sides of the tonometer body through respective windows S, S'.

Gear wheel W supported by bearings on the body of the tonometer
has its outer edge slightly protruding from the body and is consequently used as a thumb-actuated finger wheel. This gear wheel W
engages with a pinion U fixed coaxially with the anchor wheel F, and as a result, rotation of the gear wheel W by the operator's thumb causes the anchor wheel F to rotate.
Rotate.

If we consider the rotation of the gear wheel W assuming that there is no resistance to movement, the spring G connected to the anchor wheel F will rotate with the gear wheel W. This rotation is transmitted to spindle D,
Spindle D rotates spring H and arm A. When there is resistance to this movement, stress is applied to both springs G and H, causing both springs to flex. Therefore, a relative displacement occurs between the gear wheel W and the arm A. This relative deflection of the springs depends on the stiffness (spring constant) of the springs, but for simplicity, in the following description it is assumed that both springs have the same spring constant. This means that the deflection displacement corresponding to the relative rotation between anchor wheel F and arm A is equally distributed to each spring. Since both springs with equal spring constants are connected in series via spindle D, the rotation of spindle D is 1/1/2 of the relative rotation between anchor wheel F and arm A.
becomes equal to 2.

As is clear from Japanese Patent Publication No. 55-8164, the flattening member B is pressed against the patient's eye to measure the pressure inside the eyeball. While the flattening member is held in contact with the eye, the force applied to the flattening member is adjusted to provide a flattened area of a nominal size. This force is controlled by rotating the gear wheel while visually checking the indication lines of the respective protrusions Q and R and aligning the indication lines with the reference line T of the tonometer body. Anchor wheel F and arm A
The scale disk L or L' (fixed on the spindle D) moves by half a rotation relative to the
It is arranged so that the maximum load (for example, 5 g) is applied in one rotation. The indicator line on the scale disc is read when the operator observes the reference flattening of the eyeball.

As in the case of the flattening tonometer disclosed in Japanese Patent Publication No. 55-8164, a lighting device is provided to make it easier to observe the flattening of the eyeball, and a switch device is also provided for illumination when the tonometer is in use. It is being This switch device is a cam X fixed to a gear wheel W.
and a micro switch Y operated by the cam. The measuring device and the switching device themselves are not a feature of the invention.

The important effects brought about by the arrangement of springs G and H are as follows. That is, manual tonometers have practical problems, such as the fact that the spring may stick due to the force distributed in the spring, but as in the present invention, the spring G,
The configuration in which H is arranged in series allows lower spring constants to be used without such problems.

Using rotary movement of the scale reduces friction and thus improves accuracy. Additionally, mounting the spindle with multiple members that rotate in the same direction when a force is applied also reduces friction between each.

Graduation can be performed at a convenient location by applying a predetermined force to move the arm and recording the resulting graduation position. For example, in one third of the arm's movement from the energized position on the arm, the scale is accurately calibrated and a reference line T is provided on the body to record the calibrated position. If the restraining force is removed from the flattening member, the flattening member will rotate by an angle dθ and the pointing lines (located on protrusions Q and R) will remain the same.
The scale disk moves by an angle dθ/2 and the indicator always measures the force applied to the spring within the limits of the relative linear relationship of the springs.

In the tonometer of the present invention, since the scale is provided on the spindle provided between the series springs G and H, the movement of the scale due to unit force is reduced (as explained above), and the following It brings about a great effect. That is, lower values of spring constant springs can be used without requiring excessive scale movement to cover a given force range. In this case, one rotation of the graduation disk covers the entire force range. The ability to use springs with lower spring constants reduces the size of the springs, eliminates the possibility of springs wrapping around each other and causing false activations, and more importantly allows the tonometer operation to more closely approximate its linear state. As a result, no errors occur.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional front view showing the structure of the flattened tonometer of the present invention, Fig. 2 is a cross-sectional plan view of Fig. 1, and Fig. 3 is an arm and its The attached figure, Figure 4, is a front view of Figure 1, Figure 4.
Figure a is a partial sectional view taken along line 4a-4a in Figure 4, Figure 5 is a schematic diagram showing the operation of the flattening tonometer of the present invention, and Figure 6 is a partial cross-sectional view taken along line 4a-4a in Figure 4.
1 is a schematic diagram showing the operation of the prior art tonometer shown in the publication; A...Arm, B...Flattening member, D...Spindle, G, H...Spring.

Claims (1)

[Scope of Claims] 1. A main body carrying a flattening member mounted on a rotatably provided arm, a manually adjustable member that applies rotational force to the flattening member via a coil spring member, and a coil In a flattening tonometer having a measuring device for measuring the force applied to the flattening member as the spring member deforms, the force is applied by two coil springs in series with each other. , each outer end of the spring is connected to the manually adjustable member and the arm, respectively, both inner ends of the spring are fixed to a central spindle, and the measuring device includes a scale that rotates with the spindle. , the arm is provided with an indicator mark, the indicator mark is
A flattening tonometer, characterized in that the angular position of the arm is determined with respect to the main body and/or with respect to the scale of the spindle. 2. The flattened tonometer according to claim 1, wherein the spindle is mounted coaxially with the arm within a bearing carried by the arm.