JPS6314085Y2 - - Google Patents

Description

[Detailed description of the invention] (Target of the invention, industrial application field) This invention relates to a telescopic cylinder with a position detector, and is used for opening/closing the door of a machine tool and other applications where installation space is limited. .

(Prior Art) Telescopic hydraulic cylinders have conventionally been used when a long stroke is required despite a small storage space. To detect the stroke position of the cylinder, for example, when all the rams have reached their fully extended positions, a limit switch is mounted on the device frame to detect the position of a load device connected to the tip of the ram. However, since this requires time and effort to attach the detector, it is conceivable to integrate the detector into the cylinder.

Figure 1 shows an example of this.A two-stage telescopic cylinder 1 is provided with a detection rod 3 that can slide in a guide 2 and move in parallel. A dog 3a is connected to the tip of the ram of the cylinder 1, and a dog 3a for operating the detector 4 is provided at the rear end. When the cylinder 1 reaches its maximum extension position as shown by the dashed line, the dog 3a activates the detector 4 and issues a signal.
As can be seen in the figure, since the detection rod 3 becomes longer than the maximum retracted length of the cylinder 1, the advantage of using a telescopic cylinder is lost. Therefore, it is conceivable to make the detection rod 3 a telescopic type.

FIG. 2 shows an example of this, in which a two-stage telescopic cylinder 1 is provided with a two-stage telescopic detection rod 3 that can slide in a guide 2 and move in parallel. First ram 1 of cylinder 1
a and second ram 1b are connected to first rod 3b and second rod 3c of detection rod 3, respectively. A detector 4 is attached to the first rod 3b, and its actuator 4a is attached to the second rod 3b.
A groove 3d is provided on the circumferential surface of c with the rear end left in the upper axial direction.
It is operated by a dog 3a formed at the rear end of the second rod 3c.
In this example, it is not related to the position of the first ram 1a of the cylinder 1, but the relative positional relationship between the first ram 1a and the second ram 1b, that is, when the second ram 1b comes out of the first ram 1a. Detector 4 is activated. Therefore, the most extended position of the cylinder 1 can be detected only when the first ram 1a and the second ram 1b are extended and contracted in this order. As such a telescopic cylinder, there is one described in Japanese Patent Application No. 189888/1988, which was previously filed by the inventor of the present invention. However, in the case shown in FIG. 2, since the detector 4 itself is moved, the signal electric cable must be made movable, which requires a large space and is troublesome to maintain.

(Purpose of the invention) The present invention was made in view of the above-mentioned circumstances, and provides a telescopic cylinder with a position detector that can perform reliable position detection despite requiring a small installation space. The purpose is to

(Technical means) In the present invention, a telescopic detection rod in which a large-diameter rod member and a small-diameter rod member operate in multiple stages is arranged parallel to a telescopic cylinder. The fixing member that fits onto the rod member with the largest diameter of the rod is fixedly connected to the rod cover of the cylinder, and the tip of the rod member with the smallest diameter of the detection rod is connected to the tip of the smallest diameter ram of the cylinder. A position detector is attached to the fixed member, and an operating member for operating the position detector is provided at the rear end of the rod member with the largest diameter. When the rod member with the largest diameter is in the retracted position, the above-mentioned fixing member and the larger diameter rod member are operated in order so that the rod member with the smallest diameter is operated sequentially when the rod is extended, and the rod member with the largest diameter is operated sequentially when the rod is retracted. each member is provided with a locking portion which is engaged by a locking ball;
When the lock member with the smallest diameter is in the extended position, the lock ball is released from the lock groove on the fixed member side, and the lock portion where the large diameter rod member and the small diameter rod member are engaged by the lock ball is released. It is provided on a rod member with a small diameter.

(Example) The present invention will be described below by way of an example with reference to the drawings.

In FIGS. 3 and 4, 5 is a two-stage telescopic double-acting hydraulic cylinder, and this cylinder 5 includes a cylinder tube 6, a first ram 7,
Second ram 8, rod cover 9, head cover 10
It consists of etc. On the other hand, the two-stage telescopic detection rod 11 includes a fixed member 12, a first rod 1
3, a second rod 14, etc., which are arranged parallel to the cylinder 5. The second rod 14 slides inside the cylindrical first rod 13 and
is adapted to slide within one cylindrical portion 12a of a fixing member 12 having a substantially figure-eight cross section, and the other cylindrical portion 12b of the fixing member 12 is fitted onto the rod cover 9 to lock the set screw 15. The tip of the second rod 14 and the tip of the second ram 8 are fixed by nuts 14b, 8b with the connecting plate 16 externally fitted over the respective threaded portions 14a, 8b,
are integrally connected. The fixing member 12 has a mounting rod 17 made of a round bar projecting in the axial direction, and a bracket 18 is attached to the mounting rod 17.
is fixed by a set screw 18a, and a magnetic proximity actuated detector 19 with a built-in reed switch is attached to the bracket 18 by screws. A ring-shaped permanent magnet 20 is attached to the rear end of the first rod 13 with adhesive or the like, and when the first rod 13 moves in the axial direction, the permanent magnet 20 is positioned at the detector 19. Detector 1 reaches
9 is activated and outputs a signal.
21 is a filter for preventing foreign matter from entering the first rod 13, and is attached with adhesive.

Referring also to FIGS. 5A to 5C, the first rod 1
As will be described later, a plurality of through holes 22 are provided on the circumferential surface near the tip of the cylindrical portion 12a, which is a lock portion on the first rod side into which the lock ball is fitted. An annular groove 23, which also serves as a locking portion on the fixed member side, is provided on the inner circumferential surface, and an annular groove 24, which similarly serves as a locking portion on the second rod side, is provided on the outer circumferential surface near the rear end of the second rod 14. In these through holes 22, there are through holes 2
2 and either of the annular grooves 23, 24. A spherical lock ball 25 is fitted therein. These annular grooves 23 and 24 are formed into smooth rounded surfaces 23a and 24a from their respective bottoms to their openings in the tip direction, that is, on the withdrawal direction side.
a, 24a so that it can be easily moved.

A cylindrical sliding groove 26 and a ring-shaped spring receiving convex portion 27 are provided on the outer peripheral surface of the tip of the first rod 13, and a ring-shaped stopper portion 29 is provided on the inner peripheral surface of the approximately cylindrical shape. The sliding cap 28 is slidably fitted onto the first rod 13 and is biased toward the rear end, that is, toward the entry direction, by a compression spring 30. The sliding cap 28 is
This is to cover the outer periphery of the through hole 22 to prevent the lock ball 25 from jumping out when the through hole 22 comes out of the cylindrical portion 12a in the withdrawal direction. The length to the end is sufficient to cover the through hole 22 (the fifth
(See Figure C), and the movable stroke is such that when the first rod 13 reaches its most retracted position, the rear end surface of the sliding cap 28 comes into contact with the cylindrical portion 12a.
Although the stopper portion 29 moves toward the distal end within the sliding groove 26 while compressing the compression spring 30, there is still some movement margin left (see FIG. 5A).
The compression spring 30 is weak enough to cause only the sliding cap 28 to slide.

A stepped portion 31 with a larger inner diameter is provided on the inner peripheral surface of the first rod 13 near the rear end of the through hole 22, while the rear end of the outer peripheral surface of the second rod 14 is
An engaging portion 32 with a larger diameter is provided from the rear end surface of the annular groove 24 described above, and when extended, this engaging portion 32
is in contact with and engaged with the stepped portion 31, and the second rod 14 is prevented from slipping out from the first rod 13 any further. Note that 33 is a sliding member, 34 is a dust wiper, and 35 is a communication hole for air vent.

Next, the operation of the above embodiment will be explained. In the state shown in FIG. 3, that is, when the cylinder 5 is most contracted, the detector 19 is in an inactive state because the permanent magnet 20 is separated. From this state, cylinder 5
For example, when the first ram 7 and the second ram 8 begin to extend in this order, the first rod 13 is connected to the cylindrical portion 12a by the lock ball 25 and cannot be moved, so the second rod 14 is first extended. - The rod 13 slides on the inner circumferential surface and moves in the removal direction (see Fig. 5A).
Then, the second rod 14 connects the annular groove 24 to the through hole 2.
When the lock ball 25 reaches the position where it overlaps the two annular grooves 23 and 24, the lock ball 25 becomes able to fit into either of the annular grooves 23 and 24. At this time, the engaging portion 32 engages with the stepped portion 31, and the first rod 13 Start moving with Rod 14. Then, the lock ball 25 moves along the rounded surface 23a, comes out of the annular groove 23, and enters the annular groove 24 (fifth
(See Figure B). As the first rod 13 comes out,
The sliding cap 28 moves in the opposite direction and opens the through hole 2.
At the same time as the lock ball 2 comes out of the cylindrical portion 12a, the lock ball 25 is covered by the sliding cap 28, and the lock ball 25 is prevented from flying outward (see FIG. 5C). When the cylinder 5 reaches its maximum extension, the permanent magnet 20 provided at the rear end of the first rod 13 approaches the detection range of the detector 19, and the detector 19 is activated to output a signal.

When the cylinder 5 begins to contract, the second rod 14
move at the same time, but since the first rod 13 and the second rod 14 are connected by the lock ball 25, the first rod 13 also moves simultaneously and integrally in the entry direction (see Fig. 5C). Therefore, the detector 19 immediately becomes inactive. When the through hole 22 reaches inside the cylindrical part 12a, the sliding cap 28 comes into contact with the cylindrical part 12a and the compression spring 30
The lock ball 25 slides on the outer circumferential surface of the first rod 13 while being compressed (see FIG. 5B), and soon the lock ball 25 becomes fittable into the annular groove 23. Then,
The lock ball 25 moves along the rounded surface 24a, exits the annular groove 24, and enters the annular groove 23, so that the first rod 13 and the cylindrical portion 12a are connected by the lock ball 25, and the second Only the rod 14 slides within the first rod 13 (see FIG. 5A). At this time, the position where the first rod 13 stops with respect to the cylindrical portion 12a is as follows.
The shape of the rounded surfaces 23a and 24a, the position and quantity of the lock balls 25, the magnitude of sliding frictional resistance between the first rod 13 and the second rod 14, the cylindrical portion 12a and the sliding cap 28, and the compression spring 30.
In any case, the stopper portion 29 always stops at the position where it comes into contact with the front end side surface of the sliding groove 26, although this is determined depending on the strength of the slide groove 26.

When the first rod 13 and the second rod 14 move relative to each other, the air between them communicates with the outside air through the communication hole 35 and the filter 21, and does not interfere with the operation. Further, dirt, dust, etc. in the outside air are filtered by the filter 21, and the inside of the first rod 13 is kept clean. The operating position of detector 19 can be adjusted by loosening set screw 18a and moving bracket 18 along mounting rod 17. Also, multiple detectors 19 are installed,
For example, by embedding another permanent magnet in the second rod 14 and appropriately setting the axial positions of these permanent magnets and the detector, it is possible to detect even the most contracted position of the cylinder 5. be.

In the above-described embodiment, since the telescopic detection rod 11 is used, the installation dimension in the axial direction is short, and the advantages of the telescopic cylinder 5 can be fully utilized. The circumferential position of the detection rod 11 relative to the cylinder 5 is determined by the set screw 1.
By loosening 5 and rotating the cylindrical portion 12b, it can be adjusted to any desired position. The position of the detector 19 can be easily adjusted, and multiple detectors can be installed, and since the detector 19 operates without contact with the permanent magnet 20, no excessive force is applied.
The rod device can be made lightweight and compact. Since the lock ball 25 is fitted between the through hole 22 and either of the annular grooves 23, 24, the order of operation of the first rod 13 and the second rod 14 is reliably determined, and therefore the detector 19 will not malfunction. Since each annular groove 23, 24 has rounded surfaces 23a, 24a,
The lock ball 25 moves smoothly. Because of the sliding cap 28, the lock ball 25 does not fly out.

In the above embodiment, the fixing member 12, the first rod 13, and the second rod 14 are made of aluminum alloy, and the sliding cap 28 and the sliding member 33 are made of synthetic resin, so that they can operate without oil. ing. However, these materials can be selected as appropriate at the time of design. For example, if a switch operated by mechanical contact is used as the detector 19, the first rod 13 and the second rod 14 may be made of magnetic material. The second rod 14 may be cylindrical and each part may be constructed as a combination of suitable parts. If the distal end side of the cylindrical portion 12a is made longer than the annular groove 23, the lock ball 25 will not pop out within that range, so it is possible to omit the sliding cap.
The annular grooves 23 and 24 can also be formed into a plurality of recesses that are discontinuous in the circumferential direction. rock ball 2
5 can be moved by appropriately selecting the mounting position and utilizing gravity. rock ball 25
It is also possible to have a cylindrical shape.

In this embodiment, a two-stage cylinder and detection rod are used, but a three-stage cylinder or more is also possible. In that case, the structure of the relationship between the first detection rod 13 and its surroundings may be applied to the relationship between the second rod 14 and its surroundings. Further, it goes without saying that the cylinder may be of a single acting type.

(Effects of the invention) According to the invention, since a telescope type detection rod is used, the installation space is small, and each rod member operates in sequence, so reliable position detection can be performed. Since it is attached to a fixed member, there is no need to make the electric cable movable, and a compact telescopic cylinder with a position detector can be obtained.

[Brief explanation of the drawing]

1 and 2 show a conventional example of a telescopic cylinder with a position detector, FIG. 1 being a side view, FIGS. 2A and B being a side view and a front view of another example, and FIG. 3 being a side view of another example. 5 to 5 show an embodiment of the present invention, in which FIG. 3 is a partially sectional side view of a telescopic cylinder with a position detector, and FIG. 4 is a view of the detection rod in FIG. , and FIGS. 5A to 5C are enlarged cross-sectional views of the main parts of the detection rod for explaining the operating state. 5... Cylinder, 8... Second ram (ram with the smallest diameter), 9... Rod cover, 11... Detection rod, 12... Fixing member, 13... First rod (rod member with large diameter), 14... Second rod (small diameter rod member), 19... Detector (position detector), 2
0... Permanent magnet (operating member), 22... Through hole (lock part), 23... Annular groove (lock part), 24
...Annular groove (lock part), 25...Lock ball.

Claims (1)

[Claims for Utility Model Registration] 1. A telescope type detection rod in which a large diameter rod member and a small diameter rod member operate in multiple stages is arranged parallel to a telescope type cylinder, and the detection rod A fixing member that fits onto the rod member with the largest diameter is fixedly connected to the rod cover of the cylinder, and the tip of the rod member with the smallest diameter of the detection rod is connected to the tip of the smallest diameter ram of the cylinder. A position detector is attached to the fixed member, and an operating member for operating the position detector is provided at the rear end of the rod member with the largest diameter, and the detection rod is extended. When the rod member with the largest diameter is in the retracted position, the fixing member and the larger diameter rod member are operated so that the rod member with the largest diameter is in the retracted position so that the rod member with the smallest diameter is operated sequentially from the rod member with the smallest diameter when the rod member is retracted, and the rod member with the largest diameter is operated sequentially when the rod member is retracted. Each member is provided with a lock portion that is engaged by a lock ball, and when the lock member with the smallest diameter is in the extended position, the lock ball is released from the lock groove on the fixed member side and engages with the larger diameter rod member. A telescopic cylinder with a position detector, wherein the small diameter rod member is provided with a lock portion that is engaged with the small diameter rod member by the lock ball. 2. The telescopic cylinder with a position detector according to claim 1, wherein the position detector is a proximity switch that can operate without contacting the operating member.