JPS6132915Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a buffer device for a bucket elevator that sequentially scoops up and transfers various materials.

As shown in FIGS. 2 and 3, this type of bucket elevator has driving and driven sprockets 4 and 5 installed at both upper and lower ends of an elevator frame 1 via upper and lower hydraulic cylinders 2 and 3. , 5 are strung together and a large number of buckets 7 are arranged in a row on an endless chain 6. When this bucket elevator is used, for example, as a bucket elevator type unloader for unloading materials from a ship, the elevator frame 1 is suspended from the tip of a boom 8 that can be raised and raised freely from the land side, as shown in Fig. 2. The entire bucket elevator is held in an appropriate position by the raising and lowering operation of the boom 8, and the material B in the ship A is unloaded onto land. 9 is a running gutter, and 10 is a swing frame. In bucket elevators used in such marine unloaders, uplift force acts from the ship side due to vertical rocking of the ship or pushing too much into the material, and this uplift force exceeds a certain level. If this happens, there is a risk that the bottom of the ship or the lower end of the elevator will be damaged. Therefore, in order to prevent such accidents,
It is necessary to provide a shock absorber to the elevator to prevent the ship from being pushed against the ship with more than a certain force (or, conversely, from being pushed up from the ship).

A conventional example of this shock absorbing device is explained with reference to FIG. 3. Both the push side and pull side chambers of the lower hydraulic cylinder 3
A differential pressure switch 11 is provided to detect the pressure difference between R ₁ and R ₂ , and this differential pressure switch 11 connects and disconnects the pull side chamber R ₂ of the lower hydraulic cylinder 3 to the tank 12 , and a switching valve 13 that connects and disconnects the pull side chamber R 2 of the lower hydraulic cylinder 3 to the tank 12 . concubine
A switching valve 15 that connects and disconnects R ₁ from the pump 14 is controlled, and the push side chamber R ₁ of the lower hydraulic cylinder 3 and the push side chamber R ₃ of the upper hydraulic cylinder 2 are communicated. Note that the pull side chamber R ₄ of the upper hydraulic cylinder 2 is connected to the tank 12 . In such a configuration, when the uplift force F acting on the bucket elevator is small, the lower hydraulic cylinder 3 independently strokes up and down to ensure the amount of buffering force, and when the upthrust force F becomes large, , the pressure oil from the pump 14 is transferred to the lower hydraulic cylinder 3 by the operation of the differential pressure switch 11.
It is sent to the side chamber _R2 . In this way, the lower hydraulic cylinder 3 contracts (raises) and escapes from the thrust force, and at the same time, the upper hydraulic cylinder 2 expands (raises) to prevent the chain 6 from separating from the sprockets 4 and 5.

However, this conventional device had the following drawbacks. That is, in order to synchronize the upper hydraulic cylinder 2 with the lower hydraulic cylinder 3 as described above, it is necessary to make the cross-sectional areas of both cylinders 2 and 3 the same. However, since the upper hydraulic cylinder 2 supports the unloaded weight, bucket weight, etc.
As the unloading capacity increases, the size (diameter) increases, and in this case, the lower hydraulic cylinder 3 must also increase in size. Therefore, the entire device becomes unnecessarily large and heavy. In addition, since the lower hydraulic cylinder 3 is used to adjust the tension of the chain 6, it is necessary to increase the stroke as well as increase the diameter as described above, which causes problems in terms of installation space etc. as the device becomes larger and larger. was.

In view of the above-mentioned circumstances, the present invention eliminates the need for the upper and lower hydraulic cylinders to have the same diameter, thereby preventing the equipment from becoming unnecessarily large, and also enables smooth synchronized operation of both cylinders. The purpose is to provide a shock absorbing device for elevators.

The feature of the present invention is that the upper hydraulic cylinder is connected to the pump and the tank through the pressure oil supply pipe for the upper hydraulic cylinder, which is equipped with electromagnetic control valves for the push side chamber and the pull side chamber. a detector that connects the push side chamber and the pull side chamber to a pump and a tank via a pressure oil supply pipe for a lower hydraulic cylinder, and detects stroke motion of both the lower and upper hydraulic cylinders and converts it into an electric signal; A controller is provided which inputs a switching operation signal to the electromagnetic operation section of the electromagnetic control valve based on the detection signals from both the detectors, and the lower hydraulic cylinder is controlled to move the lower hydraulic cylinder over a certain length. The present invention relates to a shock absorbing device for a bucket elevator configured to cause an upper hydraulic cylinder to follow and operate in synchronization with respect to the load.

An embodiment of the present invention will be described below with reference to FIG.

20 is an elevator frame, 21 is an upper hydraulic cylinder, 22 is a lower hydraulic cylinder, 23 is a driving sprocket, 24 is a driven sprocket, 25 is an endless chain stretched between the two sprockets 23 and 24, and 26 is the chain 25. There are many buckets arranged in rows.

The lower hydraulic cylinder 22 is installed in the middle of the elevator frame 20, and the rod 22a of the cylinder 22 and the driven sprocket 24 are connected via a support frame 27. Therefore, when the lower hydraulic cylinder 22 expands and contracts (raises and lowers), the support frame 2
7 and the driven sprocket 24 move up and down together. 28, 28 are jacks provided at the lower part of the support frame 27. A rack 29 is provided upright on the upper surface of the support frame 27, and a potentiometer 31 measures the amount of rotation of a pinion 30 meshed with the rack 29.
It is configured to convert it into an electrical signal. That is, the rack 29, pinion 30, and potentiometer 31 constitute a lower detector 32, and this lower detector 32 allows the support frame 2 to be
7, that is, the length of the lower hydraulic cylinder 22, is detected and replaced with an electrical quantity.
On the other hand, also on the upper hydraulic cylinder 21 side, there is a rack 33 protruding from the rod 21a of the cylinder 21.
An upper detector 36 is provided which detects the length of the upper hydraulic cylinder 21 using a pinion 34 and a potentiometer 35 and converts the detected length into an amount of electricity. Detection signals from both detectors 32 and 36 are input to a controller 39 via amplifiers 37 and 38, respectively. This controller 39 controls both detectors 3
The detection signals from 2 and 36 are compared, and when the difference is greater than or equal to a preset value, a proportional or on/off electromagnetic control valve (hereinafter simply referred to as (abbreviated as control valve) 40 on the right or left side electromagnetic operation part,
If it is a proportional type, it will output the appropriate operating current, and if it is an on/off type, it will output an on/off signal. In this control valve 40, when no operating current or on/off signal is input from the controller 39, the spool is in the neutral position a, and when an operating current or signal is input to the right electromagnetic operation section, the spool moves to the left. Then, when an operating current or signal is input to the left electromagnetic operation section, it moves to the right and switches to position c.

41 is a pressure oil supply pipe for the push side chamber R ₃ of the upper hydraulic cylinder 21, and 42 is a pressure oil supply pipe for the pull side chamber R _4. Both the pipes 41 and 42 are connected to the hydraulic pump via the control valve 40. 43 and tank 44. Further, 45 is a pressure oil supply pipe to the pushing side chamber R ₁ of the lower hydraulic cylinder 22, and 46 is a pipe connecting the same pulling side chamber R ₂ and the oil tank 44. 47 is a pressure reducing valve provided in the pressure oil supply pipe 45 to the push side chamber R ₁ of the lower hydraulic cylinder 22; 48 is a first relief valve for setting the maximum pressure of _the push side chamber R 1; The vent control section of the first relief valve 48 is connected to the pressure reducing valve 47 and the vent control section of the second relief valve 50 via a check valve 49, and the set pressure of the first relief valve 48 is equal to the pressure of the pressure reducing valve 47+the pressure of the check valve 49. The pressure is automatically adjusted to cracking pressure.
Further, reference numerals 51 and 52 are check valves for sucking and discharging oil into the push side chamber _R1 in accordance with the vertical swinging (buffering motion) of the lower hydraulic cylinder 22.

Next, the effect will be explained.

The uplift force F acting on the bucket elevator is
When the damage is small, such as due to a small up-and-down movement of the ship, the lower hydraulic cylinder 22 independently performs a small expansion and contraction movement to exert a buffering effect. That is, the telescopic movement of the lower hydraulic cylinder 22 is detected by the lower detector 32;
When the expansion/contraction stroke is small as described above (a stroke that does not cause the chain 25 to come off the sprockets 23, 24), the difference between the detection signal from the lower detector 32 and the detection signal from the upper detector 36 is less than or equal to the set value. If so, no operating current or signal is output from the controller 39 to the control valve 40. Therefore, since the valve 40 is maintained at the neutral position a, the upper hydraulic cylinder 21 is not operated.
The lower hydraulic cylinder 22 operates independently to ensure the amount of buffering force.

When the lower hydraulic cylinder 22 contracts beyond a certain stroke and the deviation between the detection signal of the lower detector 32 and the detection signal of the upper detector 36 exceeds a set value, the controller 39 sends a signal to the right electromagnetic operating section of the control valve 40. Since an operating current or signal is output to the valve 40, the valve 40 is switched to the b position. This happens when,
Pressure oil from the pump 43 is supplied to the push side chamber R ₃ of the upper hydraulic cylinder 21 through the pressure oil supply pipe 41, so that the cylinder 21 extends (raises) and pushes up the drive sprocket 23. In this way, when the upper hydraulic cylinder 21 is extended, the upper detector 3
6 changes, the difference between it and the detection signal of the lower detector 32 is reduced, and when this difference returns to zero, the spool is returned to the neutral a position. The upper hydraulic cylinder 21 for such a lower hydraulic cylinder 22
Due to the follow-up synchronized operation, the entire bucket elevator is automatically set at a height position corresponding to the magnitude of the thrust force F, and exerts a buffering effect.
It is possible to prevent the chain 25 from coming off the sprockets 23, 24.

On the other hand, when the lower hydraulic cylinder 22 extends (descends) due to the release of the thrust force F, the deviation of the detection signals of both the detectors 32 and 36 exceeds the set value, so the control valve 40 On the other hand, it is switched to position c, and pressure oil is supplied to the pull side chamber _R4 of the upper hydraulic cylinder 21, which causes the drive sprocket 23 to
is lowered.

The control valve 40 switches and operates when the lower hydraulic cylinder 22 independently strokes a predetermined amount as described above, but the allowable expansion/contraction amount of the lower hydraulic cylinder 22 alone is determined by the detection It is determined by the set value of the signal deviation, and by adjusting this set value, the damping margin by the hydraulic cylinder 22 can be adjusted.

By the way, in addition to the combination of rack, pinion, and potentiometer mentioned in the above embodiments, the detector may also be a combination of wire, sheave, and potentiometer, or a light emitting/receiving element instead of such a tachometer system. Various types of optical sensors can be selected arbitrarily.

As described above, the present invention absorbs normal thrust force only by the lower hydraulic cylinder 22, and this thrust force cannot be fully dealt with by the lower hydraulic cylinder 22 alone. In other words, when the cylinder 22 is reduced to a size that may cause the chain 25 to come off, the stroke of the lower hydraulic cylinder 22 is detected by the lower detector 32 and the electromagnetic control valve 40 is activated. 4
0 switching operation causes the upper hydraulic cylinder 21 to extend and lift the entire bucket elevator. As described above, according to the present invention, which servo-controls the follow-up synchronized operation of the upper hydraulic cylinder 21 with respect to the lower hydraulic cylinder 22, compared to the conventional device that communicates the pushing sides of the upper and lower hydraulic cylinders with each other and obtains a synchronized action of both cylinders. Therefore, there is no need to communicate between the upper and lower hydraulic cylinders 21, 22, and therefore both cylinders 21, 2
What is necessary is just to select the diameter of 2 according to each function. That is, the upper hydraulic cylinder 21 is selected to have a capacity necessary to support the unloaded weight, bucket weight, etc.
It is sufficient to ensure the required tension and to select the appropriate tension against the thrust force from below. Therefore, it is possible to prevent the diameters of both cylinders 21 and 22 from increasing unnecessarily, and thereby prevent the entire device from increasing in size, and to solve the problem of mounting space. In addition, since it is a servo control system, the lower hydraulic cylinder 22
The follow-up synchronized operation of the upper hydraulic cylinder 21 can be performed smoothly.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a case where a bucket elevator is used in a ship unloader, and FIG. 3 is a diagram equivalent to FIG. 1 showing a conventional example. 20...Elevator frame, 21...Upper hydraulic cylinder, 22...Lower hydraulic cylinder, 23,
24... Both drive and driven sprockets, 25... Chain, 26... Bucket, 32... Lower hydraulic cylinder detector, 36... Upper hydraulic cylinder detector, 39... Controller, 40... Electromagnetic control Valves, 41, 42...Pressure oil supply pipe to the upper hydraulic cylinder, 45, 46...Pressure oil supply pipe to the lower hydraulic cylinder, 47...Pressure reducing valve of the same pipe, 48, 50...Relief valve of the same , 43...hydraulic pump, 44...tank.

Claims (1)

[Scope of utility model registration request] In a bucket elevator, in which drive and driven sprockets are attached to both upper and lower ends of an elevator frame via upper and lower hydraulic cylinders, and a large number of buckets are arranged in a row on an endless chain stretched between the two sprockets, the upper hydraulic The push side chamber and pull side chamber of the cylinder are connected to the pump and tank via a pressure oil supply line for the upper hydraulic cylinder equipped with an electromagnetic control valve, and the push side chamber and pull side chamber of the lower hydraulic cylinder are connected to the pressure oil supply line for the lower hydraulic cylinder. A detector is connected to the pump and the tank via an oil supply line, and on the other hand, detects the stroke motion of both the lower and upper hydraulic cylinders and converts it into an electrical signal, and based on the detection signals from these two detectors. A controller is provided for inputting a switching operation signal to the electromagnetic operation part of the electromagnetic control valve, and these detectors and the controller cause the upper hydraulic cylinder to follow and synchronize the stroke movement of the lower hydraulic cylinder over a certain length. A shock absorbing device for a bucket elevator, characterized in that it is configured as follows.