JPS6244211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for measuring large loads that measure large loads applied to relatively flexible members such as structures made of steel plates, stiffeners, etc. (hereinafter simply referred to as steel structures). It is related to the device.

For example, a deck lift type offshore oil drilling rig called a jack-up type rig is a platform that has several legs that can be raised and lowered and is equipped with various oil drilling equipment. The platform is towed while floating due to the buoyancy of the platform, and during work, the legs are lowered to the seabed, and the platform is then jacked up to a sufficient height above the sea surface, creating a stable working environment unaffected by waves and currents. It is often used as the most advantageous drilling equipment in terms of workability, safety, economy, etc., and is capable of conducting test drilling in offshore oil fields. When working on this jack-up platform, when the legs are lowered to the seabed and the platform is jacked up to a sufficient height above the sea surface, the rig must be monitored to ensure it does not capsize and the rig must be stably installed. Therefore, regulations (*) require that a measuring device be installed to measure the load applied to each leg (for example,
Department of Energy regulations, etc.). Along with this, there has been a demand for load measuring devices for oil rigs, maintenance purges, and other jack-up platforms used particularly in the North Sea.

As a load measuring device for the above-mentioned jack-up rig, etc., a hydraulic load meter is sometimes used, in which a bag-shaped pad filled with oil is inserted into the load transmission path, and the load is determined from the oil pressure inside the pad.

However, in the case of this hydraulic load cell, measurement errors due to changes in oil temperature appear significantly, making it extremely difficult to compensate for the temperature, and there is also a risk of damage due to stress concentration at the edges when a large load is applied. However, it also had drawbacks such as difficulty in its manufacturing method.

In view of the shortcomings of the conventional devices, the inventors of the present invention attempted to use a strain gauge type load transducer in place of the hydraulic load cell, and encountered the following problems.

That is, for example, a jack-up type rig is a so-called steel structure, and in particular, the support part (top plate) of the jack-up house that supports the reaction force received from the legs is also a steel structure and is made of a relatively flexible member (steel plate). , uniform load is not transmitted to the load converter, making accurate load measurement impossible. To deal with this problem, measurement accuracy can be improved by inserting a pad made of thick plate material with high rigidity between the load transducer and the part to be measured of the structure, but the thickness of the pad The jack house has to be correspondingly taller, creating additional problems resulting in an increase in the weight and material costs of the entire structure. These problems will be explained in more detail with reference to the drawings.
FIG. 1 is a front view showing an example in which a strain gauge type load transducer is incorporated into a rolling mill. This rolling mill feeds a plate from the direction A in the figure between upper and lower rolling rollers 1 and 2, and rolls the plate to a predetermined thickness adjusted by an adjustment screw 3 provided above. The loads applied to parts 4, 5, 6, 7, and 8 are transferred to a washer type load converter 9 and a flat type load converter 1.
It is arranged to measure at 0.11. In this rolling mill, each of the support parts 4, 5, 6, which abuts the main body part 12 and each load converter 9, 10, 11,
7 and 8 have increased rigidity, so the deformation of each support part is almost negligible, and if you pay attention to the parallelism of each support part and the load converter, the load on each support part can be reduced. It is possible to accurately measure the load applied.

However, in steel structures such as those shown in plan and front views in FIGS. 2 and 3,
The upper support plate (top plate) 14 and the lower support plate 15 that are in contact with the cylindrical load converter 13 are both made of flexible and easily deformable steel structures. One of the two is movable toward and away from the other in the vertical direction, and is provided with a shock pad 16 for absorbing impact upon contact and a pad 1 for preventing partial deformation of the shock pad 16.

When a load is applied to such a steel structure from below, for example, the pad 17 and the upper support plate 1
An inclined load or unevenly distributed load is likely to be applied to the fourth
As shown in the figure, the upper support plate 14 and the pad 1
7 etc. are deformed, and the contact surface to the load converter 13 is also deformed into a wave shape. For example, when the upper support plate 14 (indicated by the two-dot chain line) is curved upward as shown in FIG. It decreases as it approaches . On the other hand, if the upper support plate 14 is curved downward, the stress distribution will be as shown in FIG. When an unevenly distributed load is applied to the pressure receiving surface of the load converter 13 in this way, the relationship between the load and the measured value loses linearity, and for example, in the case of Fig. 5, the measured value is smaller than the actual load, and in the case of Fig. 6 In both cases, accurate measurements cannot be taken. In order to eliminate this drawback, as shown in _FIG . or by inserting a plate 19 with a large plate thickness h ₃ and high rigidity and increasing the height h ₄ of the load transducer 13 as shown in FIG. 8a. It has been found that the stress distribution becomes as shown in FIGS. 7b and 8b, the load is equalized on the pressure receiving surface of the load converter 13, and the reproducibility of the load, that is, the measurement accuracy can be improved.

However, as shown in FIGS. 7a and 8a above, the height h ₁ of the hit structure 18, the height h ₃ of the pad 19, the height h ₄ of the load converter 13, etc. become large. Inevitably, the height H between the upper support plate 14 and the pad 17
As a result, not only does this result in an increase in weight and cost, but the problem remains that it becomes weak against lateral loads.

The present invention has been made to solve these problems, and it is possible to accurately measure large loads applied to relatively flexible members such as steel structures, and to produce steel structures that are small in weight and low in cost. The purpose is to provide a large load measuring device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 9, FIG. 10, and FIG. 11 are a perspective view, a sectional view, and a plan view showing the structure of an embodiment of the present invention. 9 to 11, reference numeral 20 denotes a load transducer having an internal space 21 and a cylindrical overall shape, which is usually arranged vertically and placed at appropriate positions on the inner and outer circumferential surfaces of the cylinder. A plurality of strain gauges 22, 22, . The above load converter 20
A short cylindrical protrusion ring 24 is placed and abutted on the upper end surface 23 , and this protrusion ring 24 has an outer diameter smaller than the outer diameter of the load converter 20 . It has an inner diameter larger than the inner diameter of the load converter 20. On the other side (upper side in the figure) of this protrusion ring 24 is a disk-shaped upper backing plate 25.
are placed in contact with each other. Furthermore, a cylindrical protrusion sheet 26 is in contact with the other surface (upper surface in the figure) of the upper contact plate 25. These load converter 20, protrusion ring 24, upper backing plate 2
5 and the protrusion sheet 26 are arranged concentrically. Here, the diameter d of the protrusion sheet 26 is preferably as small as possible within a range that the supporting member (an upper common sheet 39 to be described later) that contacts the upper surface of the protrusion sheet 26 can withstand in terms of material strength. Further, the thickness t of the projection sheet 26 need only be much thinner than the height h ₁ of the contact structure 18 and the height h ₃ of the stopper 19 shown in FIGS. 7a and 8a, Incidentally, in the above embodiment, the thickness is at most 10 mm or less.

FIGS. 12 and 13 are sectional views showing two other embodiments of the present invention, and the same parts as in FIGS. 9 to 11 are designated by the same reference numerals. In the above embodiment, the protrusion ring 24 and the protrusion sheet 26 are constructed separately from the upper backing plate 25, but as shown in FIG. 12, they may all be constructed in one piece. Furthermore, the protrusion ring 24 may be provided under a plurality of conditions. Furthermore, the first
As shown in Figure 3, the upper backing plate 25 and the protrusion ring 2
4 may be integrated and only the protruding sheet 26 may be constructed separately, or these may be disposed not only above the load converter 20 but also below it.

Large load measuring device 27 configured as described above
is used with the load converter 20 installed on the base and the protruding sheet 26 supporting the load object. When the loaded object that comes into contact with the upper surface of the projection sheet 26 is a relatively flexible member 28 such as a steel structure, the entire member 28 deforms into a wave shape, as shown in FIG. 14a, and the member 28 The stress distribution also takes on a wavy shape corresponding to the deformation. The protruding sheet 26 contacts the member 28 and receives the load.
Since it is subjected to an undistributed load, the stress distribution on its surface is small at the center and becomes larger toward the periphery, as shown in FIG. 14b, for example. However, the unevenly distributed load received by the protruding sheet 26 is concentrated at the protruding sheet 26, and the pressure receiving area of the protruding sheet 26 is becoming smaller, so that the uneven distribution load that occurs on the loaded object, that is, the member 28, is reduced. It functions to prevent bending moments caused by distributed loads from being transmitted to the upper backing plate 25 and load converter 20. Furthermore, when the load is transmitted to the protrusion ring 24 via the upper backing plate 25, the upper backing plate 25
The stress is diffused (dispersed) within the ring 24, and at the stage of reaching the upper end surface of the protrusion ring 24, the stress distribution becomes considerably homogeneous as shown in FIG. 14c. Then, the load converter 20 is further connected via the protrusion ring 24.
At the stage reaching the upper end surface 23, the stress smoothing function of the protrusion ring 24 causes the load applied to the upper end surface 23 to be uniformly distributed, and the stress distribution is as shown in FIG.
As shown in the figure, the pressure is uniform over the entire pressure receiving surface. This means that the integrated value of the stress on the upper end surface 23 of the load transducer 20 exactly matches the integrated value of the stress on the member to be measured 28 shown in FIG. 14a. Therefore, the strain gauge 2 attached to the load transducer 20
The load is correctly transmitted to the locations 2, 22, . Further, according to the above configuration, the thickness (height) of the protrusion sheet 26, the upper backing plate 25, and the protrusion sheet 24 may be thin;
Since the height of the load converter 20 is also low, it is possible to measure the load with a sufficiently high accuracy, which is very advantageous because the weight and cost of the device can be reduced.

Next, an example in which the large load measuring device 27 of the present invention is applied to the above-mentioned jack up platform will be explained with reference to FIGS. 15 to 17. 29 is a leg having a pair of racks 30; 31 is the rack 3;
a support frame body with a pinion 32 that engages with 0; 3;
3 is a pinion drive device. The support frame 31
A shock pad 34 is attached to the upper surface of the holder. On the lower common seat 37 supported by a plurality of hanging bolts 36 from the top plate side of the jack house 35, three large load measuring devices 27 are installed via lower backing plates 38, and each protruding seat 26 ,
It abuts from below against an upper common sheet 39 attached to the lower surface of the jack house 35.

The operation of the large load measuring device for the jack-up platform having such a configuration will be explained.

As mentioned above, when the jack platform is moved, the pinion drive device 33 rotates the pinion 32 in the direction shown, and the rack 30 that engages with the pinion 32 and the leg 29 that is integral with the rack 30 are rotated by the pinion drive device 33.
to rise. Since the platform floats due to its own buoyancy, it is towed in that state to the target offshore oil field location.

Next, when drilling (test drilling) an offshore oil field, the pinion drive device 33 is driven in the opposite direction to the above-mentioned direction.
9 to the seabed, and then jack up the platform to a sufficient height above the sea surface. On this occasion,
A load is applied to the support frame 31 in an upward direction in the drawing due to the reaction force of the pinion 32 that lowers the rack 30, and this load is applied as follows: shock pad 34 → lower common seat 37 → lower backing plate 38 → load converter 20 →
Protrusion ring 24 → upper backing plate 25 → protrusion sheet 2
6→upper common sheet 39→jacket house (top plate) 35, and becomes a force that pushes up the platform. In this way, the large load measuring device 27 is inserted between the load transmission paths, and is composed of a combination of the load converter 20, the protrusion ring 24, the upper backing plate 25, and the protrusion sheet 26. As mentioned above, it is possible to measure with high precision a large load (in this example, the weight of the platform is 4000t to 20000t) applied to a relatively flexible member such as the top plate 28 of the jack house 35 made of steel structure. can. Thus, for example, when jacking up a platform, it is possible to monitor the proportion of the load on several legs.
Prevents the risk of capsizing. In particular, it is extremely important to stabilize the legs by adapting them to the soft ground on the ocean floor. One way to stabilize this is by pumping seawater into the platform and placing a large amount of weight on the legs.
Since one or two of the several legs are lifted and the load is concentrated on the remaining legs, it is necessary to carefully operate while monitoring the load balance on the legs. The present invention is extremely suitable as a load measuring device in such a case.

In addition, although the above application example shows the case of a jack-up platform, it can also be applied to large load measurement for land, civil engineering, and construction without departing from the gist of the invention.

As described in detail above, according to the present invention, the height of the load measuring device as a whole is reduced as much as possible, the weight is small, the cost is reduced, and the structure is extremely strong against lateral loads. It is possible to provide a large load measuring device for steel structures, etc., which can measure with high precision large loads applied to relatively flexible members, such as steel structures, which have been considered difficult.

[Brief explanation of the drawing]

Figure 1 is a front view showing an example of a conventional load measuring device, and Figures 2 to 8 are diagrams for explaining problems when measuring loads on relatively flexible members such as steel structures. Figures 2 and 3 are a plan view and a front view showing a configuration example in which a load converter is inserted between steel structures, and Figure 4 is a front view showing the deformation state of the steel structure under load. Figures 5 and 6 are diagrams showing the stress distribution state on the upper end surface of the load transducer, and Figure 7a.
and b are a front view showing an example of a configuration in which a load converter is inserted between steel structures, and a diagram showing the stress distribution state of each part in the same figure, and Fig. 8 a and b are different configurations from Fig. 7 a. A front view showing an example and a diagram showing the stress distribution state of each part in the same example, Fig. 9, Fig. 1
0 and 11 are perspective views, front central vertical cross-sectional views, and plan views showing the structure of one embodiment of the present invention, and FIGS. 12 and 13 show the structure of two other embodiments of the present invention. Front center longitudinal sectional view, 1st
Figures 4a, b, c, and d are diagrams showing the stress distribution state in each part of the large load measuring device according to the present invention, No. 15
16 and 17 are a plan view, a front view, and an enlarged view of the main parts in FIG. 16, showing an example of application of the present invention. 20... Load converter, 21... Internal space, 22
... Strain gauge, 23 ... Upper end surface, 24 ... Projection ring, 25 ... Upper backing plate, 26 ... Projection sheet, 27 ... Large load measuring device, 28 ... Top plate,
29... Leg, 30... Rack, 31... Support frame, 32... Pinion, 33... Pinion drive device, 34... Shock pad, 35... Jacket house, 37... Lower common seat, 38... Lower Backing plate, 39... Upper common sheet.

Claims (1)

[Claims] 1 In a load measuring device that measures a large load applied to a relatively flexible member such as a steel structure using a load converter inserted between the load transmission path, the overall shape is cylindrical and is attached to the circumferential surface. a load transducer that converts the load applied to both end faces of the strain gauge into an electrical quantity; a short cylindrical protrusion ring which has an outer diameter larger than the inner diameter of the load converter and whose one end surface abuts one end surface of the load transducer; A large load measuring device for a steel structure, etc., comprising a caul plate that is in contact with or integrated with the caul plate, and a cylindrical protrusion sheet that is abutted on or integrated with the other side of the caul plate.