JPH0121026Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Purpose of the invention Γ Industrial application field This invention evens out the slack that occurs in the screen net (woven net, hereinafter simply referred to as the net) attached to the sieving machine.
It also relates to a device that can be easily removed and restored to its original tension state, and is particularly aimed at sieving machines that use fine mesh.

Γ Prior Art In general, the mesh of a sieving machine is subjected to equally large loads due to the supplied material and the motion of the machine, and the stress and strain on the wires that make up the mesh are extremely high. As a result, permanent strain occurs in the entire net and the net becomes in a so-called slack state, but in the past it has been considered extremely difficult to restore this to its original uniform tension state. It is well known that the most efficient way to use a sieving machine is to tension it as strongly as possible and apply the mechanical motion to it, but if the mesh gradually loosens, the machine Since the movement is not faithfully transmitted to the net, and the net does not move in a predetermined manner, the flow of the feed material becomes unstable, the sieving efficiency decreases, and the sieving function becomes completely ineffective. If operation continues in this state, the net will eventually become fatigued and damaged. A method of tensioning the mesh intended to correct the loosening of the mesh in such a sieving machine was published in 1982.
Various inventions and devices are known, such as those disclosed in Patent Application No. 31437, Patent Application Publication No. 187369, 1987, and Utility Model Application Publication No. 61-19483.

Γ Problems that the invention aims to solve The most difficult problem to solve with the net tensioning method with the above purpose is to evenly remove slack in the net so that the tension is as uniform as possible, as close to the original state as possible. It is about recovery.

The phenomenon and countermeasures differ depending on the shape of the sieve frame to which the screen is attached, i.e., whether it is circular or square, but in the case of a square frame in particular, wrinkles occur at the four corners of the screen surface. It's difficult.

The present invention restores the net attached to such a net frame to its original state with as uniform tension as possible,
The purpose is to provide a mesh tensioning device that prevents wrinkles from occurring at the four corners, and the following description will mainly be made in detail for the case of a rectangular sieve frame.

(b) Structure of the invention Γ Means for solving the problem The present invention is applicable to cases where the sieving frame is circular or square (square, rectangular), and the top of the frame is equipped with a screen for the purpose of sieving. A strong auxiliary net (a punched board may be used) is attached in parallel to the lower surface of the net for the purpose of support, and the diameter is approximately the same as the spatial distance in the parallel space.
Especially when the sieve frame is rectangular, a sealed expansion structure is formed by configuring cylinder tubes that expand due to internal pressure in an X-shape and communicating with each other at their intersections to integrate them.
Each X-shaped cylindrical tube is arranged to match the diagonal line of the frame, and the tube is inflated by introducing air through an air valve provided in the cylindrical tube.Hereinafter, such an X-shaped closed expansion structure is simply referred to as an air spring. I'll decide.

Γ Effect When air is supplied to the air spring from the air valve, the entire spring expands and the cylindrical tube extends in the radial direction, pressing up and down the nets attached to both the top and bottom of the frame. At that time, the force pushing the upper and lower nets is equal, but since the bottom net is a strong support net with a coarse mesh, its deformation is small, but the top net has a large amount of deformation, so it cannot sufficiently absorb the slack. It can make you nervous. The net on the top (naturally the net on the bottom) and the air spring are arranged along the diagonal of the rectangular frame, so they are in contact with all four corners, and the air pressure inside the tube is working uniformly. It easily fits the amount of slack in the top net. Therefore, the net surface can be tensioned evenly without wrinkles occurring at the four corners of the net.

Γ Example Figure 1 is a plan view of a rectangular sieve frame in which this invention was implemented.
A single sieving machine is completed by stacking several layers. 2 is a side view taken along the line A--A in FIG. 1, and FIG. 3 is a plan view showing the air spring 4 as a single unit. 1st
2 and 3, 2 is a fine mesh attached to the upper surface of the frame for the purpose of sieving, 3 is a strong auxiliary mesh with coarse mesh for the purpose of supporting the air spring 4, and the frame is 1, but it also serves to accommodate and direct a tapping ball for preventing clogging, as shown at 10 in the figure. 4 is an air spring,
5 is an air supply pipe for it, which is made of metal, rubber, or plastic, and is connected to the sieve frame 1 as shown in the figure.
It has a structure in which the air spring 4 is guided outside by passing through the frame at the end thereof, and the air spring 4 is fixed within the frame. Next, a pressure gauge 8 for indicating the internal pressure of the air spring and an air valve 9 for replenishing air are provided at the three-way port 7 through the flexible piping 6, but such pressure gauges and air valves are usually fixed to the sieving machine. It is best to install it in a section to protect it from the vibration of the sieve frame. Moreover, the air valve 9 and the pressure gauge 8 can be appropriately integrated and omitted when the sieve frames are stacked in several stages.
Now, the cross-sectional shape of the cylindrical tube part of the air spring 4 is circular.
Alternatively, it may be oval, bellows-shaped, or any modification thereof, as long as it is easily deformable and inflatable, but it is necessary that the ends be closed like a lid. The diameter equivalent dimension is approximated to the spatial distance between the net 2 and the auxiliary net 3,
The air springs 4 are arranged in an X-shape along the diagonal line almost in contact with the inner surface of the frame 1 as shown in the figure, and have a sealed structure in which they communicate at intersections, and are made of rubber or plastic. FIG. 4 shows a modification of the air spring shown in FIG. 3 in consideration of production design. That is, the structure is such that the aforementioned cylindrical tube portion is divided into four equal cylindrical tubes, which are fixed to the X-shaped four-way opening 11 as shown in FIG. 6, and communicated with each other in an airtight manner. The four-way opening 11 is made of a material such as metal, wood, ceramic, glass, rubber, or plastic.

Now, the general operating situation of such a sieve frame is that the raw materials to be sieved are fed onto the net 2 from the right arrow in Figure 1, and are transferred in the direction of the left arrow by the movement of the sieve. , a sieving action is performed by the screen 2. Among raw materials,
Particles larger than the opening of the mesh 2 are discharged as on-screen products in the direction of the arrow on the left, while particles smaller than that fall through the opening of the mesh 2, but the opening of the auxiliary mesh 3 is Since it is considerably coarser than that of net 2, it passes through without difficulty and becomes a product under the net.

On the other hand, the tapping ball 10 jumps freely on the auxiliary net 3 and hits the bottom surface of the net 2, thereby contributing to preventing or eliminating clogging. It also works well. In addition, since the space between the net 2 and the auxiliary net 3 is divided into four sections by the X-shaped air spring, the tapping balls placed in each section will not be unevenly mixed and will act equally on the entire surface of the net. do.

(c) Effect of the invention The essence of the invention is that an air spring pushes up from under the net to remove slack in the net and generate tension. On the other hand, the fact that the net is constantly pushed up by air pressure along the diagonal of the frame means that the net is supported only by the peripheral tension of the frame. Not only
Since it is also elastically supported diagonally,
Helps ensure the rigidity of the screen surface. This is because the stiffness of a mesh surface is generally proportional to the applied tension and inversely proportional to the supported span. In this case, by slightly pushing up the air spring, the tension is restored, while the supporting span becomes shorter, so the rigidity of the net increases in both respects.

Therefore, the effects of this device can be summarized as follows.

1 Effect of increasing the rigidity of the mesh surface High rigidity means that the mesh is stretched taut, so it always moves in the same way as the machine, improving sieving performance. Naturally, it can also withstand a large net surface load.

2 The effect of constantly tightening the net The net is constantly pushed up by the expansion force of the air spring,
Tension is applied immediately as slack occurs.

3. Effect of evenly applying tension to the net The arrangement of the X-shaped air springs along the diagonal line eliminates slack on the entire screen surface, applies even tension, and prevents wrinkles from forming at the four corners of the frame.

4 Effect of easy operation to restore the tension of the net Air springs can be supplied with air from the outside even during operation, and the internal pressure can be adjusted to adjust the pushing force, so the operation to restore the tension is extremely easy.

5. Advantageous effects for ball tapping Since the net is taut, the action and effect of ball tapping will be better. In addition, the tapping ball acts in an orderly manner within the four sections formed by the air springs, and is not biased.

By combining the above effects, the sieving performance is improved and at the same time the life of the net is extended.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the entire shape of a unit sieve frame equipped with the present invention. FIG. 2 is a side view of the A-A cross section. FIG. 3 is a plan view of the air spring that is the core of the present invention. FIG. 4 is a plan view of another embodiment of the air spring. FIG. 5 is a sectional view of the air spring of FIG. 4. FIG. 6 is a sectional view of the central communication portion of the air spring shown in FIG. 4. 1... Sieve frame, 2... Net, 3... Auxiliary net, 4
... Air spring, 5 ... Air supply pipe, 6 ... Flexible piping, 7 ... Three-way port, 8 ... Pressure gauge, 9 ... Air valve, 10 ... Tapping ball, 11 ... Four-way port.

Claims (1)

[Scope of utility model registration request] A screen net for the purpose of sieving is attached to the top of the sieve frame, and a strong auxiliary net with a coarser mesh for support purposes is attached in parallel to the bottom of the sieve frame. Approximate to the distance,
Cylindrical tubes that expand due to internal pressure are configured in an X-shape, and an integrated sealed expansion structure is placed in communication with each other at their intersections. A device that tensions the upper screen net by pressing it up and down.