JPH0122082Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stroke control mechanism used, for example, to control the movement of a spindle of a measuring instrument by a predetermined distance.

For example, as shown in FIG. 1, when measuring the height of the object to be measured 20 that is intermittently fed between the spindle 11 and the base 30 of the dimension measuring instrument 10, first,
When feeding the object to be measured, the spindle 11 is lifted to a predetermined height, then the spindle 11 is pressed onto the object to be measured that has been sent into the space to measure its dimensions, and then the spindle 11 is lifted again to the predetermined height. , the object to be measured is sent out, and the next object to be measured is sent in. In this case, the spindle 11 has a height exceeding at least the maximum dimension of the object to be measured, that is, a measuring instrument 10 having a stroke corresponding to this maximum dimension is usually selected, so When lifting, conversely, and measuring, spindle 1
1 and its lifting means are separated, that is, the spindle 11 is free.
It needs to be able to be pressed upwards.

To do this, the collar 13 is fixed to the upper protruding end (or lower protruding end) of the spindle 11, and a through hole of the movable body 12 having a diameter larger than that is inserted into the spindle 11 below the collar 13. , it is sufficient to move the moving body up and down by a predetermined stroke. In this way, while moving the moving body 12 upward, the upper surface of the moving body 12 and the collar portion 13 of the spindle 11 are
When the lower surface of the spindle 11 comes into contact with the lower surface of the
The moving body 12 moves down as one until the tip of the measuring instrument 10 comes into contact with the object to be measured 20, but after the contact, only the moving object 12 descends, and the spindle 11 is pressed against the object to be measured 20 only by the pressing force of the measuring instrument 10 itself. It will be done.

Now, the easiest way to control the stroke of the moving body 12 between the maximum raised position and the maximum lowered position is manually, but there is a risk of overrun during the raising and lowering. In the event of an overrun, an unreasonable force is applied to the measuring instrument 10 and its supporting position shifts, causing a shift in the zero point of the measuring instrument and in the moving direction of the spindle. For this reason, stroke control using a motor, air cylinder, etc. is performed. In other words, when using a motor, a female screw hole is provided in the movable body and a feed screw rod is screwed into the hole, and the movable body is moved up and down by forward and reverse rotation of the motor connected to the feed screw rod, and the motor The stroke is controlled by the number of rotations of the air cylinder, and the air cylinder directly connects the piston to the moving body to control the stroke. However, the former has the problem of requiring an expensive motor such as a pulse motor and a complicated control circuit to prevent overruns.
In the latter case, an air source is required and the overall size is large, so there is a problem that the installation location of the measuring instrument is limited.

The present invention eliminates the above-mentioned drawbacks and provides a stroke control mechanism with a simple structure and no overrun.The present invention has a feed screw formed in the middle of a round bar whose both ends are rotatably supported by a holder. The feed screw and a female thread formed on the movable body are screwed together, and the straight portions at both ends of the feed screw are formed to have a slightly smaller diameter than the inner diameter of the female thread of the movable body, and a spring is attached to each straight portion. As a result, when the round bar is rotated forward or reverse, the moving body moves forward or backward in the axial direction of the round bar, and when the moving body is disengaged from the threaded state with the feed screw, the moving body moves forward or backward in the axial direction of the round bar. The backward motion stops, and as a result, the stroke of the moving body becomes a predetermined value determined as the sum of the length of the feed screw and the thickness of the moving body, so there is no risk of overrun. As a result, when the round bar is rotated in reverse or forward direction, the spring is compressed and pushes the moving body toward the feed screw.
Immediately after the movable body is screwed into the feed screw again, it is moved forward.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In Figures 2 and 3, 3 is a feed screw 4 in the middle part.
is formed, and has straight portions 5, 6 at both ends thereof, and the tip portions 7, 8 of the straight portions 5, 6 are round bars rotatably supported by the holders 1, 2, respectively. The screw 4 is screwed into a female thread bored in the movable body 12, and the diameter of the straight parts 5, 6 is made slightly smaller than the inner diameter of the female thread. Springs 9, 9' are interposed.

In the above configuration, when a handle is attached to the protruding shaft end portion of one end 8 of the round bar 3 and the round bar 3 is rotated manually or combined with a motor and rotated, the moving body 12 is moved in the axial direction of the round bar 3. When the round bar 3 is rotated clockwise in FIG. 2, the moving body 12 is moved upward, and as a result of this movement, the moving body 12 is moved upward as shown in FIG.
2 comes off the feed screw 4, the movable body 12 comes to a halt at that position even if the round bar 3 rotates. During this movement, the spring 9 interposed in the straight portion 5 is compressed between the holding body 1 and the movable body 12, and constantly applies a downward pushing force to the movable body 12. Therefore, when the round bar 3 is rotated counterclockwise, the moving body 12 is immediately rotated.
The female thread is engaged with the feed screw 4, and the movable body 12 is moved downward. And as a result of that movement,
When the moving body 12 comes off the lower end of the feed screw 4,
At that position, the moving body 12 is in a stopped state,
At that time, the spring 9' will be compressed, so when the round bar 3 is rotated clockwise again, the moving body is immediately screwed into the feed screw 4 and moved upward. is started. Therefore, moving body 1
The stroke l of No. 2 is uniquely determined as the sum of the length l' of the feed screw 4 and the length t of the moving body, and no overrun can occur.

Next, an embodiment in which the present invention is used to control the lifting of the spindle 11 in the dimension measuring instrument 10 shown in FIG. 1 will be described. The stroke control mechanism is indicated by a broken line on the right side of the figure, and the base 4
Above the L-shaped frame 40 whose base is fixed to 0, holders 1 and 2 extend leftward from above and below. The portions 7 and 8 are supported and positioned vertically, and the feed screw 4 thereof is threadedly engaged with the female thread of the right extending portion of the movable body 12, which has a through hole inserted through the upper protruding portion of the spindle 11. Springs 9 and 9' are interposed in the upper and lower straight parts of the smaller diameter, respectively, and the downwardly protruding tip 8 of the round bar 3 rotates a reversible motor 50 whose base is fixed to the frame 40. It is connected to the shaft 51.

In the above, when the motor 50 is rotated clockwise, the round bar 3 is rotated, the movable body 12 is moved upward, and the upper surface of the left end of the movable body 12 is brought into contact with the lower surface of the collar 13 of the spindle 11. After contact, the spindle 11 is lifted upward by the moving body 12. As a result of this movement, when the right side of the movable body 12 comes off the feed screw 4 of the round bar 3, the movable body 12 stops at that position. In this state, the drive of the motor 50 is stopped, and the object to be measured 20 is sent into the space between the lower end of the spindle 11 and the base 30. Subsequently, the motor 50 is reversed. At this time, since the movable body 12 is always pressed downward by the upper spring 9, it is immediately engaged with the feed screw 4, the movable body 12 is moved downward, and the spindle 11 is also moved downward accordingly. .
When the lower end of the spindle 1 reaches the upper surface of the object to be measured 20, the descent of the spindle 11 stops at that position, but the movable body 12 further descends, and as a result, the spindle pressing spring in the measuring instrument 10 is activated. The spindle 11 is pressed onto the object to be measured 20 by the pressing force. Subsequently, the moving body 12 further descends,
When the threaded state with the feed screw 4 comes off, the moving body 1
2 becomes stationary at that position. Therefore, the height of the object to be measured 20 can be determined from the output of the dimension measuring instrument 10 at this time. Hereinafter, the motor 5
0 is rotated in the normal direction, the spindle 11 is lifted, and the same operation as described above is repeated.

As described above, the present invention feeds the moving body by screwing the female thread of the moving body and the feed screw, and stops feeding the moving body by separating both screws, and
In the separated state, the spring presses the movable body in the direction of the feed screw, so accurate stroke control is performed smoothly and the configuration is extremely simple.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a measurement system of a measuring instrument which is an example of the application of the present invention, FIGS. 2 and 3 are front views with partial cross sections showing an embodiment of the present invention, and FIG. Figure 3 shows the movable body and the feed screw when they are screwed together, and Figure 3 shows them when they are separated. 1, 2: Holder, 3: Round bar, 4: Feed screw,
5, 6: Straight part, 9, 9': Spring.

Claims (1)

[Scope of utility model registration request] A feed screw is formed in the middle part of a round bar whose both ends are rotatably supported by a holding body, and the feed screw and an internal thread formed on the movable body are screwed together, and the straight parts at both ends of the feed screw are screwed together. The stroke control mechanism is formed to have a diameter slightly smaller than the inner diameter of the female thread of the moving body, and a spring is interposed in each straight portion of the stroke control mechanism.