DE8433624U1 - MEASURING VALVE FOR THE LOADING OF LOADS ON A ROPE, ESPECIALLY A CRANE - Google Patents

Description

Measuring device for weighing loads on one Rope, especially a crane

The innovation relates to a transducer for weighing loads on a rope, in particular one Crane.

For many goods, it is necessary, before or after loading by a crane on z. B. a vehicle that Determine the weight of the goods for accounting and storage purposes. For a long time it was customary to load the cargo weigh yourself on a separate weighing device or weigh the vehicle before and after loading. However, it is much more efficient to weigh the goods during the loading process by adding the weight of the is determined on the crane rope hanging load. For this purpose, transducers are used that are suitable Way are attached to or in the crane rope, and in connection with a mechanical, electrical or electronic Transmission and display allow weighing of a load hanging on the crane rope.

There are essentially two basic types of transducers known for the stated purpose. Transducers of the first type are so-called "dynamometers"; H.

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Force gauges that are used in the course of the rope or between j§ Seil und Fep ^ rpunkt are inserted i You thus take the

; | entire load itself and have to stair accordingly
>! be bil and elaborately built. The load determination er * -

I follows by measuring the deformation of an elastic

m intermediate member, z. B. a spiral spring o * ä *, in the measuring

I, value transducer, with the spring the full on the rope

Attacks hanging load. Because of the stability required
1 'lity, especially when weighing heavy loads in terms of weight

In the range of tons, such transducers need a lot

I have a strong build and are therefore expensive and time-consuming

the production. There is also the disadvantage of a relative! large space requirements, which may lead to too

; large reduction in the lifting height of the crane z. B. at

low-rise bridge cranes, as well as the requirement of a rope separation.

j | The other known basic type of measurement value recording <5 is

attached to the crane rope without this having to be separated. The rope is roughly wave-like

· '■ Form guided over a pressure-sensitive element and

I is displayed above and below the element with the measured value

f transducer connected. With increasing load on the rope

I the endeavor of the rope increases to a straight line

I course. This means that the rope exerts increasing pressure

I select the pressure-sensitive element without, however, the

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Deformation of the rope over this element is compensated. Such transducers are essential lighter and more space-saving than the type described above, but they have a serious, safety-related disadvantage. The rope is in the area of the transducer over a short length relatively strongly deflected and deformed. Especially with large loads, it can be due to the strong, small-scale load In the kinks of the rope, premature rope damage and thus impairment of safety can occur. This point in particular has already led to complaints about such transducers from technical monitoring associations (Tiiv) led.

It is therefore the task of a transducer for weighing loads on a rope, in particular of a crane, which avoids the disadvantages described and in particular saves space and weight is constructed, which is inexpensive, which can be attached to different ropes in a simple manner and which, above all, only insignificantly stresses the rope in addition to the attached load.

The solution to this problem is achieved according to the invention by a transducer for weighing loads on a rope, in particular a crane _{t where the measured value}

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transducer is attached to the rope on which the transducer an L-shaped body with at least one elastically deformable, depending on the rope tension a strain gauge that converts elastic deformation into electrical measured values *

Due to the new design of the transducer as an L-shaped body with strain gauges it is advantageously achieved that the structure is very light and compact and only requires a few lengths Has decimeters and that only the slightest deformations in the range below millimeters for load weighing required are.

In a preferred embodiment of the transducer, the first leg of the L-shaped body is below firmly connected to the rope at an approximately right angle. The second leg running roughly parallel to the rope is with a tie rod behind or encompassing the rope and slightly deflecting towards the leg tied together. As the load on the rope increases, the aim is increasingly to assume a straight course and compensate for the deflection. As a result, the tie rod creates an increasing force on the second Legs of the L-shaped body exercised. The first leg is on the other hand because of its fixed connection with

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the rope largely immobile, so that there is a deformation, here a movement of the legs towards each other. Because of the high sensitivity of the strain gauge, the smallest deformations and thus the smallest deflections on the rope by the tie rod are sufficient, which, according to initial experience, are in the millimeter range in practical use. The additional strain on the rope is thus largely minimized.

It has proven to be particularly favorable for a clear measuring effect of the strain gauge to be attached approximately in the middle area of the first leg of the L-shaped body in a roughly parallel to the longitudinal axis of the rope, this intersecting or almost intersecting plane proved. This area of the body and this orientation the mounting surface offer a clearly detectable as well as a linear, proportional to the rope tension Deformation.

To reinforce the measuring effect, the L-shaped body has at least one groove in the first leg, which the elastic deformation in the area of the strain gauge or in the leg area covered by it enlarged. By means of such a groove or such grooves, the cross-section of the leg is depending on the groove depth reduced and thereby a greater deformation, im

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remaining part of the leg in the vicinity of the groove or grooves with constant tension in the rope

aims. This is particularly advantageous if the measured value is superimposed by interference signals caused by rope vibrations, Vibrations are caused by rotating machine parts or similar sources.

The placement of the Kut in the area between the rope and the strain gauge on the side facing away from the second leg of the first leg. This is the elastic deformation in the remaining part of the leg in the area around the groove or its end with that seen from the point of application of the tie rod on the second leg the best possible leverage. As the optimum for a clear measuring effect while remaining at the same time Sufficient stability of the leg has a groove depth of about half to a little more than that Half of the material thickness or the cross-section of the leg has been proven.

Another preferred embodiment of the transducer has an attachment of the strain gauge or the Strain gauges in the area of the common end of both legs. This attachment in the area of Kneeling point of the L-shaped body results in particular,

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if there are no grooves, the clearest measuring effect « This is due to the fact that the area in question is the intersection of the two that act when the rope is loaded Is leverage and is therefore subject to the greatest deformation.

To protect the strain gauge and to achieve the most interference-free measurement effect possible, it is advantageous * to attach the strain gauge sunk at the end of a hole, the depth of which is about half the Material thickness or the cross section of the L-shaped body corresponds in the direction of the bore.

There is a further improvement in the measuring effect in the case of a transducer with one strain gauge each at the inner end of two in a line from two opposite side surfaces of the L-shaped body from extending bores is attached, the Depth is slightly less than half the material thickness or the cross section of the L-shaped body. By this double arrangement reduces the measuring errors and the result of the weighing becomes more exact.

TJm to ensure that the measured value absorbs when weighing is operated in its most favorable work area, the tie rod that the second leg is appropriate

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- fides L-shaped body connects to the rope, in its Adjustable length. This can e.g. B. by moving the leg-side end of the tie rod in a hole in the second leg and subsequent locking by means of locking screws or by turning nuts done at a threaded end of the tie rod. What is achieved hereby is that the size of the Deformation of the L-shaped body and thus the Mefteffekt can be adjusted at a constant load until the most favorable working range of the measuring transducer for the specific application has been reached. Particularly A large weighing range can thus advantageously be covered with just one type of measurement transducer. This saves effort in storage and, above all, in adapting the evaluation electronics to the Measurement transducers, with the fact that different measurement transducers have identical strain gauges are operable "

As the most favorable form of the L-shaped body to achieve a clear measuring effect while at the same time saving space A body has proven to have a first leg, which runs approximately at right angles to the rope is shorter than the second leg. This shape results in both good stability and favorable length ratios the lever of the occurring forces.

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A particularly quick setting of a fluctuation-free measured value after lifting a load results when the transducer is attached to the rope in the kind that the free end of the approximately parallel to the rope extending second leg in the direction of the with the end of the rope being loaded.

The influence of rope vibrations on the transducer is expediently minimized in that it is attached to the rope in the vicinity of the fixed point of the rope. In addition, the transducer is not a larger one there Movements and thus the risk of damage and also the transmission cables to the evaluation electronics and advertisements are largely fixed.

A preferred embodiment of the transducer according to the innovation for weighing loads on one Rope, in particular a crane, is explained in more detail below with reference to a drawing. They show in detail:

Figure 1 is a side view of an attached to a rope modern transducer and

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FIG. 2 shows a section along the line AA in FIG. 1 in a plane perpendicular to the longitudinal axis of the rope.

If, as shown in FIG. 1, the transducer 1 consists of

, | i an L-shaped body 2 with a first, approximately

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•• J * right to a rope 4 running leg 2 ¹ and one

'I' wide legs running roughly parallel to 4 rope

Il 2 ¹¹ . The first leg 2 'is via a fastening

(| device 8 firmly connected to rope 4, whereby the

I Ceil 4 because of the low weight of the measured value recording

y mers 1 is only insignificantly claimed. The second

t * ^; Leg 2 ^{11 of} the L-shaped body 2 is in the area

One free end is connected to the rope 4 via a tie rod 5. The tie rod 5 embraces or engages behind the rope 4 and deflects it slightly towards the leg 2 ¹¹ , which for clarity in FIG. 1 in one

j is shown exaggerated scale. When the

; Rope 4 strives to have a straight course

to be assumed and thus exerts a force directed towards the rope via the tie rod 5 on the second leg 2 ¹¹ . There

g the first leg 2 ^{1 is} firmly connected to the rope 4,

I the L-shaped body is deformed

ζ To measure this proportional to the rope load

I deformations are, as Fig. 2 shows, in bores 7, 7 '

I in side surfaces of the first parallel to the rope 4

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Leg 2 * strain gauges 3, 3 'attached, which convert even the smallest deformations into electrical measured values in order to work with the smallest possible rope deflections and thus the smallest possible rope load, the first leg 2 ^{1 has} in the area between the rope 4 or fastening device 8 and the strain gauges 3 , 3 ^{1 has} a groove 6. This groove 6 is made in the ^{side of the first leg 2 ′ facing away from the second leg 2 11} and has a depth of slightly more than half the material thickness of the leg 2 ¹ . Because of the weakening of the leg 2 ¹ in the area of the groove 6, the elastic deformation is concentrated in the area around it, in which the strain gauge 3 is also attached, so that a clearer measuring effect is achieved with the same load on the cable 4.

With the innovation described it has been possible to create a transducer for weighing loads on one To create rope, in particular a crane, which is simple, space-saving and inexpensive to manufacture ensures exact weighing of loads and, in particular, the rope to which it is attached, only minimally deformed and stressed, so that one can speak of an optimal solution to the task at hand.

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Claims (12)

-Al- protection claims 1. transducer for weighing loads on a rope, in particular a crane, the transducer being attached to the rope, characterized in that the transducer (1) has an L-shaped body (2) which is elastically deformable as a function of the rope tension with at least one strain gauge (3) which converts the elastic deformation into electrical measured values. , 2. transducer according to claim 1, characterized in that the first leg (2 ¹ ) of the L-shaped body (2) is firmly connected at an approximately right angle to the rope (4) and that the second, approximately parallel to the rope (4) extending leg (2 ″) is connected to a tie rod (5) which surrounds the cable (4) and deflects slightly towards the leg (2 ″). / 3. transducer according to claims 1 and 2, characterized in that the strain gauge (3) approximately in the central region of the first leg (2 ¹ ) of the L-shaped body (2) in a to the longitudinal axis of the rope (4) approximately parallel, this intersecting plane is attached. η Λ » - A 2 - 4. A transducer according to claims 1 to 3, characterized in that the first leg (2 ¹ ) has at least ¹¹³ a groove (6) reinforcing the elastic deformation in the region of the strain gauge (3), χ 5. transducer according to claims 1 bic 4, characterized in that the groove (6) in the area between the rope (4) and the strain gauge (3) in ^the second leg (2 ¹¹ ) facing away from the side of the first leg (2 ¹ ) and that the groove (6) has a depth of about half to slightly more than half the material thickness of the first leg (2 ¹ ) ./ 6. transducer according to claims 1 and 2, characterized in that the strain gauge \ 3) is attached in the region of the common end of both legs (2 ', 2 ^11). _y 7. transducer according to claims 1 to 6, characterized in that the strain gauges', 3) is attached to the end of a bore (7), the depth of which corresponds to about half the material thickness of the L-shaped body (2) in the direction of the bore * ■ a a 4 α · · · -A3 " 8. transducer according to claims 1 to Ί, characterized
characterized in that one strain gauge (3)
each at the inner end of two in a line from
two opposite side faces of the L-shaped
Body (2) from running bores (7, 7 ') is attached, the depth of which is slightly less than half
the material thickness of the L-shaped body (2) 9. transducers according to claims 1 to 8, characterized characterized in that the ώοη second leg (2 ¹¹ )
of the L-shaped body (2) with the rope (4)
connecting tie rods (5) adjustable in length 10. transducer according to claims 1 to 9, thereby §j characterized in that the first, approximately at right angles to the 1 ^{Leg (2 1} ) running through the rope is shorter than the 1 second leg (2 ¹¹ ) of the L-shaped body (2). I. 11. transducer according to claims 1 to 10, § characterized in that the free end of the approximately | second leg | running parallel to the rope (4) (2 ¹¹ ) of the L-shaped body (2) in the direction of the | end of the rope (4) loaded with the load | shows. / ' 1 · * Eο c ■> - A 4 - 12. Measuring transducer after the. ' Claims ΐ to 11 / characterized in that the transducer (1) is connected to the rope (4) in the vicinity of its fixed point. </