JPH0321468Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a breakage warning system for structures such as booms and arms of hydraulic power shovels.

(Prior Art) When large loads are repeatedly applied to structures made of steel plates, such as the boom and arm of a hydraulic power shovel, cracks may occur. If this crack is left as it is, it will progress and become a penetrating crack, which may eventually destroy the structure and cause a serious accident.

In order to prevent such accidents, it is possible to prevent the occurrence and progression of cracks, or to detect the occurrence and progression of cracks and repair or reinforce the location where the cracks occur.

Conventionally, in order to detect such cracks, visible areas are detected visually, and areas that cannot be seen, such as inside a structure, are detected by non-destructive testing such as ultrasonic flaw detection.

(Problem that the invention attempts to solve) However, with this method, it is impossible to detect cracks that occur in locations that are invisible to the naked eye and where a detector for non-destructive testing cannot be installed.
Furthermore, although the visual inspection method is simple, even if the crack is visible, it is often impossible to detect the crack if there is mud, grease, etc. attached to the spot. On the other hand, non-destructive testing methods such as ultrasonic flaw detection require special testing techniques and testing time, and are therefore not simple and expensive. moreover,
Regardless of whether a visual inspection method or a non-destructive inspection method is employed, periodic inspections are required, and the occurrence and progression of cracks cannot be completely detected.

(Means for solving the problem) The present invention was devised to solve the above problem, and its gist is that it is a closed space defined by a structure on which a load acts. , an airtightness indicator consisting of a gas filling nozzle that seals pressurized gas in the sealed space, a pressure sensitive element that responds to pressure changes of the gas sealed in the sealed space, and a display element that is linked to the pressure sensitive element. In the structure destruction alarm device, the airtightness indicator comprises an inflatable and deflated bag with a clear color and communicating with the sealed space, and a translucent plate disposed on the outside of the bag. When inflated, the bag adheres tightly to the inside of the translucent plate, making its color visible from the outside; when the bag deflates, the bag separates from the translucent plate, making its color invisible. The feature lies in the structure destruction warning system.

(Example) Hereinafter, the present invention will be specifically described with reference to an example in which the present invention is applied to the illustrated hydraulic power shovel.

In Figures 1 and 2, 100 is a boom;
200 is an arm, 300 is a bucket, 400 is a boom cylinder for raising and lowering the boom 100,
500 is an arm cylinder for swinging the arm 200, and 600 is a bucket cylinder for swinging the bucket 300. As shown in FIG. 2, the boom 100 and the arm 200 are box-shaped by welding steel plates, and define a closed space 2. A gas sealing nozzle 30 for sealing pressurized gas into the sealed space 2 and an airtightness indicator 40 for detecting and displaying changes in the pressure of the gas sealed in the sealed space 2 are attached to the boom 100 and the arm 200. ing.

FIG. 3 shows an example of a gas-filled nozzle 30, in which 30a is a main body, 30b is a check ball, 30c is a pressing spring, 30d is an air inlet, 30e is a gasket, and 30f is a cap. be. A gasket 30 is installed between the main body 30a and the structure.
It is attached to a structure by tightening the main body 30a with d interposed therebetween. Then, by blowing compressed air from the air inlet 30d, the check ball 3 is
0b is pressed down against the spring 30e to seal compressed air in the sealed space 2. After filling the compressed air, the air inlet 30d is covered with a cap 30f.

FIG. 4 shows another example of the gas filling nozzle 30, in which 30g is a main body 30h is a valve, 30i is a rubber tube, 30j is an air inlet, 30k is a gasket, 30
l is the presser foot cap. The main body 30g is attached to a structure with a gasket 30k interposed therebetween, and compressed air is blown into the air inlet 30j to expand the rubber tube 30i and seal it in the closed space 2. By screwing in the presser cap 30l and pressing the rubber tube 30i against the shoulder of the main body 30g, leakage of the compressed air in the closed space 2 is prevented.

The specific structure of the gas indicator 40 is shown in FIGS. 5 and 6. In the figure, reference numeral 1 denotes a main body formed entirely in the shape of a bolt, and an engaging portion 1 formed on the head of the main body.
A threaded part 1b is formed on the leg part by engaging a with a tool such as a spanner or wrench and twisting it.
is screwed into the screw hole 3a of the structure defining the sealed space 2, and the gasket 17 is interposed between the lower surface of the flange portion 1c of the main body 1 and the upper surface of the structure. Can be attached airtight to objects.

The specific structure of the airtight indicator 40 is shown in FIGS. 5 and 6. A nozzle 29 is provided in the hollow part 5 of the airtight indicator body 1 and connected to the pressure guiding hole 12. Then, a flexible or stretchable bag 31 such as a rubber balloon is fixed to the nozzle 29 with a mounting ring 32. 33 is a semitransparent plate, and 34 is a layer of semitransparent material. The bag 31 preferably has a clear surface color, or may be printed so that the surface changes color when expanded. FIG. 6 shows a state in which the bag 31 is filled with the fluid in the sealed space 2 through the pressure guiding hole 12. In this state, the bag 31 is in close contact with the translucent plate 33, so that the clear color of the bag 31 can be visually recognized from the outside. FIG. 5 shows a state in which the pressure inside the bag 31 is gone; in this state, the bag 31 is deflated and the color of the bag 31 cannot be seen from the outside. That is, in a normal state, it is difficult to see the inside, but when the bag 31, which has a vivid color, is brought into close contact with the back surface of the semi-transparent plate 33, the color becomes visible from the outside. The airtight indicator 40 has the advantage of having a large display section that is easy to see, and that it is highly sensitive because it utilizes the expansion of the bag 31.

(Operations and Effects of the Invention) Although the embodiments have been specifically explained above, in the present invention, there is a sealed space defined by a structure on which a load acts, and a gas enclosure in which pressurized gas is sealed in the sealed space. An airtight indicator comprising a nozzle, a pressure sensitive element that responds to changes in the pressure of the gas sealed in the sealed space, and a display element interlocked with the pressure sensitive element, the airtight indicator communicating with the sealed space. A bag that can be expanded and contracted and has a clear color, and a translucent plate placed on the outside of the bag, and when the bag is inflated, the bag comes into close contact with the inside of the translucent plate, making the color visible from the outside. Therefore, when the bag contracts, the bag separates from the translucent plate and its color becomes invisible, making it extremely easy to check whether or not a through crack has occurred in the structure by visually checking the airtightness indicator. can be determined.

Therefore, the occurrence of penetrating cracks that could not be detected by visual inspection of the exterior of the structure or non-destructive inspection using an ultrasonic flaw detector can be immediately detected and an alarm can be issued, thereby preventing the destruction of the structure and preventing serious accidents. Occurrence can be prevented.

Although compressed air was sealed in the sealed space in the above embodiment, it is of course possible to fill in high pressure nitrogen gas or the like, or to reduce the pressure in the sealed space.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a side view showing the boom and arm of a hydraulic power shovel to which the invention is applied, Fig. 2 is a cross-sectional view of the same essential parts, and Fig. 3 is a gas-filled valve. 4 is a sectional view showing another example of a gas-filled valve, FIGS. 5 and 6 are an example of an airtight indicator, and FIG. 5 is a state in which the airtightness is leaked. A vertical cross-sectional view showing
FIG. 6 is a longitudinal sectional view showing the normal state. 100,200...Structure, 2...Closed space,
30... Gas filling nozzle, 40... Airtightness indicator,
31...Bag, 33...Semi-transparent board.

Claims (1)

[Scope of utility model registration request] A sealed space defined by a structure on which a load acts, a gas filling nozzle that seals pressurized gas in the sealed space, and a pressure-sensitive element that responds to pressure changes in the gas sealed in the sealed space. and a destruction alarm system for a structure comprising an airtight indicator consisting of a display element interlocked with the pressure-sensitive element, wherein the airtight indicator is an expandable and deflated bag with a vivid color, communicating with the sealed space; A translucent plate is placed on the outside of the bag, and when the bag is inflated, the bag comes into close contact with the inside of the translucent plate, making its color visible from the outside, and when the bag is deflated, the bag becomes a semi-transparent plate. 1. A destruction warning device for a structure, characterized in that the device is configured such that its color becomes invisible when separated from the object.