JPS639601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pistol grip type instrument for measuring internal diameter. More particularly, a body having fitting means for mounting a comparator with a measuring feeler on the body, an inner diameter measuring feeler movable in the body in the radial direction, and an inner diameter measuring feeler movable in the body in the axial direction of the body. a movable device including a rod member such that one end is connected to the inner diameter measuring feeler and the other end is in direct contact with the measuring feeler of the comparator; a thrust member attached to the rod member of the movable device; and a thrust member movable at one end thereof. The device constantly pushes the thrust member in a direction such that the inner diameter measuring feeler projects from the body, while actuating a main spring disposed within the body, the other end of which is supported by a fixed part of the body, and a trigger. a trigger disposed against the main spring and supported by the thrust member to stop the main spring from acting on the inner diameter measuring feeler when the main spring is actuated; The present invention relates to a pistol grip type inner diameter measuring instrument comprising an auxiliary spring disposed within the body, which acts in a direction opposite to the main spring to retract the inner diameter measuring feeler when the inner diameter measuring feeler is moved.

Measuring instruments of this type are already known in which the thrust member supporting the trigger is rigidly attached to the control rod of the mobile device.

However, conventional internal diameter measuring instruments of this type have the disadvantage that the position of the trigger corresponding to the fully retracted condition of the measuring feeler is not at the end of its stroke. As a result, if the user pulls the trigger too hard, the trigger will move past the end of its normal stroke, causing pressure to be applied to a portion of the movable member by the trigger and transmitted through the movable member to the comparator. Causes problems.

Currently, electronic comparators are being used in increasing quantities, but the rod of the electronic comparator has low strength and cannot be pressed too strongly against the body of the measuring instrument, so as mentioned above, it is difficult to apply excessive pressure to the trigger. This action causes the rod to collapse within the body, resulting in a completely inaccurate measurement reading without the user noticing.

In addition, different types of internal diameter measuring instruments are already known, such as the one described in Japanese Patent Publication No. 7744/1983. In this type of measuring instrument, the trigger is directly and firmly fixed on the rod member of the movable device, and there is no secondary spring for pulling back the inner diameter measuring feeler, and instead a direct transmission method using a rack and gears is adopted. has been done.

In this measuring instrument, which differs from the present invention, the control rod of the mobile device is brought into contact with the measuring feeler of the comparator via a safety system with a retraction spring. This safety system consists of a bush slidably mounted around one end of a control rod whose length is limited by two thrusts. Between one of the two thrusts and the collar of the bushing, a retraction spring is compressed to force the bushing against the other thrust, and the bushing is further arranged such that its end rests against the measuring feeler of the comparator. It is set up.

Therefore, even if the user applies too much force on the trigger to cause it to pass the end of the travel of the comparator's measuring feeler, the excess stroke of the rod member will cause the bush to resist the retraction spring and to its compression. This will be absorbed by displacing the rod in the opposite direction relative to the control rod.

However, in such a safety system,
The force of the pullback spring acting on the bushing is
It has the ability to pop the inner diameter measuring feeler out of the instrument body and must be much greater than the spring force of the moving device to ensure measurement reliability. This means that in the event of the passing of the end of the travel of the measuring feeler of the comparator as described above, the comparator will be under pressure to force itself out of the body of the instrument, and this pressure will be exerted by the main spring. It is much larger than the force of , and increases further depending on the magnitude of the displacement.

Furthermore, if the user suddenly releases the trigger after bringing the trigger to its extreme position for fitting the measuring feeler into the part to be measured, the measuring feeler of the comparator will be subject to the already fairly strong main spring pressure. The pressure of the retraction spring beyond the end of travel causes the control rod of the movable device connected to the inner diameter measuring feeler to violently move. Therefore, the inner diameter measuring feeler is violently pushed to the outside of the instrument body, and there is a risk that its measuring end may damage the inner diameter surface of the part to be measured.

The present invention provides an inner diameter measuring instrument that eliminates the above drawbacks by having the structure described in the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained below based on embodiments shown in the drawings.

As shown in FIG.
and body part 2 screwed onto body part 1.
and the grip 3 attached to the body part 2. The fitting device is a tightening button 4.
and a tightening nut 5 for mounting the comparator 6 into the body parts 1, 2 and the grip 3. A rod member is provided in the body, the rod member being a cylindrical rod 7 which is slidable in the axial direction within the body part 1 and is arranged coaxially with the rod 7 and is in contact with the right end of the rod 7. It is formed by a cylindrical rod 8 arranged to

Rod 8 is connected to comparator 6 at the right end 9 of rod 8.
The measuring feeler 10 is arranged to operate. A cylindrical thrust member 11 is attached to the rod 8 by a pin 12. A main spring 13 is arranged in the body part 2 around the rod 8 on the right side of the thrust member 11, one end of which constantly presses against the thrust member 11, and the other end carried by a fixed part of the body. In this measuring instrument, the fixed part is the tightening bush 4.

As shown at the left end of Fig. 1, body part 1
A measuring head 14 is attached to the holder, and three feelers 15 for measuring the inner diameter of the part to be measured are provided. The left end of the rod 7 is pressed by the main spring 13 so as to protrude from the measuring head 14.
It is in contact with the fillers 15. body part 1
, the rod 7 is inserted in the opposite direction to the main spring 13.
A sub-spring 16 is provided to actuate the. The secondary spring 16 is substantially the same as the main spring 1.
3, but substantially stronger than the spring of the comparator 6 which projects the measuring feeler 10.

A trigger 10 is pivotally mounted on the grip 3 and operates a thrust member 11 against the action of the main spring 13 in order to retract the feeler 15 under the action of the main spring 13. In the position indicated by the dotted line, the trigger 17 is in the inactive position,
That is, it is held by the main spring 13 and placed at the leftmost position. In the position shown in dotted lines, the trigger 17 is arranged in such a position that the feeler 15 is retracted into the measuring head 14 . In the position shown by the solid line, the trigger 17 is arranged at its end of rotational movement. During the passage of the trigger 17 from the position shown in dotted lines to the position shown in solid lines, the thrust member 11 acts on the measuring feeler 10 of the comparator 6 and on the end 9 of the rod 8 such that the comparator 6 slides sufficiently within the clamping bush 4. are doing.

When the trigger 17 is rotated to the rightmost position, the rod 7 is not in contact with the rod 8. Of course, while the trigger 17 rotates from the position shown by the dotted line to the position shown by the chain line, the rod 7
is in contact with Rod 8. The amount by which the rods 7, 8 are separated accurately indicates the displacement that will be applied to the comparator 6 when an excessive force is applied to the trigger 17.

FIGS. 2 and 3 show an example of the invention which eliminates this drawback, in which the same parts as in the measuring instrument shown in FIG. 1 are given the same reference numerals. As shown in FIG. 2, the feeler 15 is connected to the measuring head 1
4 by a predetermined amount, and is in contact with the inner diameter of the part to be measured 18 having an unknown inner diameter.

In this example, the rod member is formed solely by a cylindrical rod 7a which is axially displaceable within the body parts 1, 2, the rod 7a actuating the feeler 15 at its left end and the comparator 6 at its right end.
is in contact with the measuring feeler 10 of. This rod member is a cylindrical member similar to the thrust member 11 of FIG. 1, and has a thrust member 11a slidably fitted onto the rod 7a. A circular stopper 19 is fixed to the rod 7a for limiting leftward displacement of the thrust member 11a fitted to the rod 7a by the action of the main spring 13. The sub spring 16 is attached to the body portion 2
It is arranged so as to act on a circular stopper 20 carried on the rod 7a and fixed to the rod 7a. The trigger 17 is disposed in a non-actuating position at the position shown by the dotted line, and is rotated to the position shown by the solid line to measure the inner diameter. When the trigger 17 is turned further to the right, the feeler 15 is completely retracted into the measuring head 14, and the trigger 17 is pulled further to a position opposite the inner part 21 of the grip 3, as shown in FIG. When the feeler 15 is rotated to this point, the feeler 15 is completely retracted into the measuring head 14 and the rod 7a is no longer in contact with the feeler 15. However, this rod 7a
cannot act on the comparator 6 with sufficient force to fully slide it into the clamping bush 4. That is, when the trigger 17 is further rotated and pulled to the right in the figure beyond the position where the feeler 15 is completely retracted, the trigger 17 presses the thrust member 11a to the right, but the thrust member 1
1a is slidably fitted to the rod 7a, so that the right moving end of the measuring feeler 10 separates from the circular stopper 19 and further compresses the main spring 13, thus eliminating the drawbacks of conventional internal diameter measuring instruments. , the force that the rod 7a acts on the filler 10 is,
There is only the force of the sub spring 16, and the force is so weak that it does not cause the disadvantages of conventional inner diameter measuring instruments.

The tension of the main spring 13 is, for example, 3 kg, and the tension of the secondary spring 16 is 300 g.
The tension of the comparator 6 acting on the measuring feeler 10 is 200 g. In this way, the drawbacks of known internal diameter measuring instruments are completely eliminated.

Of course, the rod 7a need not be a single member as shown in FIG. 1, and since the thrust member 11a is movable relative to the rod 7a, it is also possible to act in substantially the same manner.

As mentioned above, the inner diameter measuring device with this configuration has the following drawbacks. That is, after the trigger 17 is rotated to the position shown by the solid line in FIG.
When the main spring 13 is strong, it activates the thrust member 11a and therefore the rod 1.
7a is actuated, the rod 7a reaches the rear of the feeler 15 and presses it. As a result, firstly,
The feeler 15 is pushed outward, damaging the inner diameter surface of the part to be measured, and secondly, the rod 7
a presses against the feeler 15 and rebounds in the opposite direction, contacts and presses the measuring feeler 10, and slides on the comparator 6 in the clamping bush 4, causing an error in the inner diameter measurement as described above with reference to FIG. It ends up.

4, 5, and 6 are embodiments of the present invention that eliminate the above-mentioned drawbacks, in which a brake, such as a hydraulic brake, is provided in the thrust member 11a, and the trigger is This prevents the thrust member 11a from rapidly displacing when it is released from the above-mentioned rotational right-hand position.

In order to make the explanation of this embodiment easier to understand, the same parts as in the example shown in FIGS. 2 and 3 are given the same reference numerals with the addition of "b".

In this embodiment, the body includes body portion 1b
It consists of a body part 2b fitted into the body part 1b, and a grip 3b attached to the body part 2b. The divided bush 4b is
A comparator 6b is fixed to the measuring instrument. The tightening nut 5b tightens the split bush 4b. Furthermore, the comparator 6b is provided with a measurement feeler 10b.

The trigger 17b functions to displace the thrust member 11b to the right. When the trigger 17b is rotatably disposed at the rightmost position in FIG. 4, the thrust member 11b is in contact with the fixed stopper 21a.

The thrust member 11b is hollow, and inside,
A cylindrical chamber 22 is arranged, and the cylindrical chamber 22
is closed at both ends with heads 23 and 24 in a fluid-tight manner. Inside the cylindrical chamber 22, a piston 25 is screwed onto the stopper 21a and fixed to the body.
is installed. The cylindrical chamber 22 is axially slidable relative to the fixed piston 25. The main spring 13b is supported by the piston 25 and is arranged to act on the head 24 of the thrust member 11b. A passage 26 is bored in the piston 25 and communicates with the cylindrical chambers 22 arranged on both sides thereof. The cylindrical chamber 22 is filled with a liquid such as oil.

1 of the pistons 25 shown on the right side of FIG.
A small elastic plate 29 in which a hole 30 smaller than the passage 26 is bored by a screw 28 is fixed on the surface. This elastic plate 29 has two functions, firstly, it acts as a valve that closes the passage 26 almost completely when it is in contact with the piston 25, and secondly, the elastic plate 29 When 29 is bent to the right to open passageway 26, fluid is communicated from one side of piston 25 to the other side substantially without resistance.
The hole 30 acts as a dart pot when the elastic plate 29 is in contact with the piston.

Rod 7b and rod 7c perform the same function as rod 7 in the first embodiment. rod 7b
is free to move piston 25 and thrust member 11
Although it slides through b, it penetrates in a fluid-tight manner. At its one end 7d, the rod 7b is in contact with the measuring feeler 10b.

The pistol grip type internal diameter measuring device constructed as described above operates as follows.

Before measuring the inner diameter, trigger 17b is rotated to the position shown in solid line in FIG. In this position, the measuring feeler 15b is moved against the measuring head 15 by the action of the secondary spring 16b, which is substantially weaker than the primary spring 13b for the reasons explained above with respect to the first embodiment.
It is drawn in within b. Through the action of trigger 17b, thrust member 11b reaches the rightmost position shown in FIG. While the trigger 17b is rotating, it rotates from the position shown by the chain line in FIG. The pressure in the left cylindrical chamber 22 increases. This pressure increase deforms the elastic plate 29 as shown in FIG. 5, and the liquid is communicated from the left side to the right side through the passage 26. When the thrust member 11b reaches the position shown in FIG. 4 and the trigger 17b is suddenly released, the main spring 13b presses the head 24 and moves to the left, reducing the pressure in the left cylindrical chamber 22. As the pressure in the cylindrical chamber on the right side is higher than that on the left side, the elastic plate 29 comes into contact with the right end of the passage 26, and the liquid decreases the moving speed of the dart pot, that is, the thrust member 11b by the action of the main spring 13b. It is closed except for the passage formed by the hole 30 which acts as a pressure brake. Therefore, the impact of the rod 7c on the measuring feeler 15b does not occur, so that the drawbacks of conventional internal diameter measuring devices can be overcome.

As shown in FIG. 6, the measurement feeler 15b
is in contact with the inner diameter of the part to be measured 18b, the thrust member 11b is separated from the stopper 21a, and the sub spring 16b acts on the measuring feeler 10b via the rods 7c, 7b.

The positions of the parts shown in FIG. 6 correspond to the positions of the parts shown in FIG.
is in contact with the collar 32 of the main spring 13.
The thrust of rod 7b is transmitted to rod 7b. In the position of each part shown in FIG. 4, the tube 31 is separated from the collar 32.

As described above, as a modification of each embodiment of the present inner diameter measuring instrument, the action of the doss pot is
This can be implemented by providing a predetermined gap between the cylindrical chamber of the thrust member 11b and the inside of the cylindrical chamber of the thrust member 11b using the hole 30. Similarly, the thrust member 11b
When the thrust member 11b is displaced to the right in FIG. 5 by the action of the main spring 13b, the elastic plate 29 is displaced and liquid flows through the passage 26, and when the thrust member 11b is moved to the left by the action of the main spring 13b, the piston 25 and the thrust member Liquid can flow through the gap between the cylindrical chamber of 11b and the cylindrical chamber.

[Brief explanation of the drawing]

1 is a schematic sectional view of a conventional pistol grip type measuring device for measuring the internal diameter; FIG. 2 is a sectional view of the pistol grip type internal diameter measuring device with the trigger disposed in the inactive position; and FIG. The figure is a cross-sectional view of the inner diameter measuring device of the present invention when the trigger is rotated to the moving end, and FIG. 4 is a cross-sectional view of the inner diameter measuring instrument of the present invention when the trigger is rotated to the moving end and the feeler is retracted. 5 is an enlarged sectional view showing the brake of the present invention, and FIG. 6 is a sectional view when measuring the inner diameter using the measuring instrument shown in FIG. 4. 1, 2: Body part, 7, 7b, 7c: Rod member, 10, 10b: Measurement feeler, 11, 11
b: Thrust member, 13, 13b: Main spring, 14, 14b: Measuring head, 15, 15b:
Feeler, 16, 16b: Sub-spring, 17,
17b: trigger, 19: stopper, 20: stopper, 22, 22b: cylindrical chamber, 25, 25b: piston, 26: passage, 29: elastic plate, 30: dart pot.

Claims (1)

[Scope of Claims] 1. A body having fitting means for mounting a comparator with a measuring feeler on the body; an inner diameter measuring feeler movable in the radial direction within the body;
a movable device including a rod member movable in the body in the axial direction of the body, one end of which is connected to the inner diameter measuring feeler and the other end of which is in direct contact with the measuring feeler of the comparator; a thrust member mounted; at one end of which a movable device constantly pushes the thrust member in a direction such that the inner diameter measuring feeler protrudes from the body, while the other end is supported by a fixed part of the body and disposed within the body; a main spring; a trigger disposed against the main spring and supported by the thrust member to stop the main spring from acting on the inner diameter measuring feeler when the trigger is actuated; and; a pistol grip type comprising a secondary spring disposed within the body, which is weaker than the primary spring and acts in the opposite direction to the primary spring to retract the inner diameter measuring feeler when the trigger is actuated. In the internal diameter measuring instrument, the thrust member is slidably mounted on the rod member, and the pressure of the main spring limits displacement of the thrust member relative to the rod member when the trigger is released. A stop is provided on the rod member to suppress the displacement of the thrust member relative to the rod member such that the force exerted by the rod member on the measuring feeler of the comparator is equal to the force exerted on the trigger upon actuation of the trigger. The force of the secondary spring shall not be exceeded regardless of the
Moreover, when the trigger is suddenly released, the impact force of the inner diameter measuring feeler on the inner diameter surface of the part to be measured, which is caused by the main spring, causes the relative force between the thrust member and the rod member of the movable device to 1. A pistol grip type internal diameter measuring instrument, characterized in that a brake is connected to the thrust member so as to limit the displacement by suppressing the displacement. 2. Claim 1, wherein the brake is disposed inside the thrust member.
Pistol grip type internal diameter measuring device as described in . 3. The brake is formed by a piston fixed to the body; and two heads at both ends thereof, the piston is housed therein, and the main spring is connected to one of the heads. a cylindrical chamber of said thrust member disposed between said piston and a liquid filling said cylindrical chamber on both sides of said piston; 3. A pistol grip type inner diameter measuring instrument according to claim 2, characterized in that the piston is a hydraulic brake consisting of a dowel pot disposed on the piston to suppress displacement. 4. The dart pot consists of a hole in an elastic plate fixed to the piston surface opposite to the working surface of the main spring, and when the elastic plate pulls the trigger, a piston having a larger cross-sectional area than the hole in the dart pot opens. The elastic plate is configured to close a passage cut in the piston, and the elastic plate is configured to exert a valve action on a portion of the piston where the passage opens when the trigger is released. A pistol grip type internal diameter measuring instrument according to claim 3.