SU59909A1 - Instrument for testing springs and bellows with the aim of selecting them for bellows aneroid boxes - Google Patents

Description

As one of the sensors of the automatic control of the aircraft is a bellows aneroid. It consists mainly of a bellows having the shape of a harmonious round metal box and a coil spring.

The top and bottom covers are usually soldered to the bellows, forming with it a hermetically closed cavity from which air is pumped to a residual pressure not exceeding 0.1 mm Hg.

Thus, due to the harmonic shape of the bellows, the aneroid has the ability to vary its length depending on the magnitude of the external pressure.

The temperature conditions do not affect the length of the aneroid, since the change in the residual pressure inside the aneroid, resulting from a change in temperature, is negligible compared to the value of the external pressure.

In the production of aneroids, it is very difficult to obtain equal bellows with respect to elasticity, whereas a well-defined length is required for aneroid at a given barometric pressure and a well-defined stroke for a given external pressure difference. Therefore, in order to avoid a large amount of waste of unfit elasticity of the bellows, the question of the selection of the spring bellows to the existing bellows, providing aneroid with a constant characteristic, is of great importance.

To obtain aneroids that satisfy a given characteristic, it is necessary to choose the bellows and spring by elasticity so that two conditions are satisfied: first, the pressure force on the aneroid at sea level must be balanced by the total elastic force of the bellows and the spring at the length LN of them corresponding to the pressure at sea, and, secondly, when the aircraft is lifted to a certain height, the atmospheric pressure is balanced by the total force composed of the elastic forces of the bellows and the spring with their length L corresponding to this at pressure.

Since, however, neither the bellows nor the springs have a strictly linear dependence on the load stroke, which is especially true for the bellows, they should be tested in the interval of the two above-mentioned extreme pressures, the required values in the two extreme positions -dl LH and L .

If we denote the average total voltage of the bellows and the spring for the upper limit through CpA, and for the lower one through CpB, then, taking in half the value of these values, we can determine the deviations a and b from these values of the measured springs and the deviations a and (5 measurable bellows.

These deviations for some measured objects will be positive, for others negative.

If we now choose a bellows with the same absolute values of these values, but with opposite signs, to the spring with some values of deviations a and b, then by making a two-bellows aneroid of them, you can get an instrument that does not match the linear characteristic of the bellows and the spring in separately will be mutually compensated.

The proposed device is intended to test springs and bellows in the above direction, i.e., to determine the positive and negative deviations a and b from half the total voltage of the bellows and the spring corresponding to a given aneroid box characteristic, which you can choose from among the measured bellows and springs necessary pairs with the same absolute value of these deviations, but with different signs (-n and -).

In this device, as in the known devices for testing springs in general: e, a lever balance with an indicator of linear deformation of the test specimen is used, but, unlike the known ones, two lever weights are connected to the test specimen (spring or bellows) of which serve to determine the positive and other negative deviations of the stresses from half the total voltage of the bellows and the spring,

corresponding to a given aneroid box characteristic.

In FIG. 1 shows a device of a conventional bellows aneroid; FIG. 2 - a general view of the device, partially in section; FIG. 3 - the same in the plan; FIG. 4 shows a section along the CD of FIG. 2; FIG. 5 is an EF section of FIG. 2; FIG. 6-9 - various parts of the device; FIG. 10 shows a modified form of making one of the scales; FIG. And-diagram of electrical inclusions of the device.

The assembled bellows aneroid consists of a bellows, a spring, and springs attached to the bellows of the upper and lower lids with processes, of which the sprout of the upper lid serves to strengthen the tension on it that transfers the pressure of the bellows to the controls (Fig. 1).

The apparatus constituting the subject matter is shown in general and in some detail in FIG. 2-9.

As can be seen from FIG. 2, two vertically opposite, horizontal edges of the prism 1 fixedly mounted in the upper part of the frame 2 are the support lines of the levers: the upper 3 and the lower 4. The latter are linked to each other by means of prisms 5 and 6, which sit on the movable the rod 7 and the points of application of the reactions of the measured bellows or spring and the second supports of the levers 3 and 4, which do not allow the latter to disintegrate.

Since the rocking of the levers occurs around the edges of the prism 1, the rod 7 is able to move in the vertical direction within the limits limited by the contact stops 8.

The horizontal distance between the vertical axes of the prisms 4-5 (or 6) and 1-9 (or 10) is as fast as 1:10. Therefore, the force applied in the vertical direction to the rod 7 can be balanced by weights placed on the left 11 of the right 12 scales, having a weight ten times smaller than the applied load.

The lower end of the rod 7 is provided with a chuck 13 with a threaded socket for screwing in the fixture required for the test.

On the upper arm 3, to balance the levers with all the fixtures and weights weighing cups mounted on them, there is a load 14 with an adjusting screw 15. When the levers are balanced, the equilibrium indicator 16 stands against the zero division of the equilibrium scale 17.

The change in length is made by the handwheel 32, when turned, which raises or lowers the lower chuck 18, tightly mounted and pinned on the square-cut screw 19.

In order for the cartridge 18 not to rotate when the handwheel 32 is rotated, a guide rod 20 is screwed to the bottom side, the column 21 on the left encompassing the circular fork, and the length indicator 22 on the right (Fig. 3),

In the lower cartridge 18, as well as in the upper cartridge 13, the fixtures are screwed in to allow the bellows 23 to be rigidly fastened to the planes between which the length is measured.

FIG. 6 shows a view of such a device from above (upper); FIG. 7 - from the bottom. Both devices are the same. They consist of a cup 24 with an external thread, two clamping plates 25 with a gear for interlocking on an arc of 60 °, a clamping nut 26, a fuse 28 providing a clamp of the bellows between the end surface of the clamping nut and the inner surface of the clamping plates with a force not exceeding frictional forces from the pressure of the spring 27, the handle 29, which carries out the solution of the pressure plates, the springs 27 and the adjusting screws 30.

The bellows clamp is manufactured as follows.

The bellows is placed close to the end surface of the clamping nut of the lower device, after which the handle 29 is rotated up to the stop of the edges of the clamping

plates in the inner corrugations of the bellows.

The clamping nut 26 is then rotated with the help of a fuse towards the pressure plates until the fuse starts to rotate. Finally, using the handwheel 32, the upper end of the bellows is brought into contact with the end face of the pressure nut of the upper device. Thereafter, the second and third steps are repeated.

The length is measured using a length scale of 31 and a metal strip 33 pulled over frame 34, which is screwed to pointer 22.

Before the bellows is installed, the zero division of the length scale is aligned with the pointer strip for the moment when the surfaces between which the length is measured contact, and when the zero division of the equilibrium scale 17 coincides with the equilibrium indicator 16.

The adjustment to the zero division of the length scale is carried out by moving the length scale along the front groove, which has a mum in the right column 35, in which the scale slides and is fastened with screws 36 (Fig. 5).

The length scale has two nonius - the left 37 and the right 38 (Fig. 2), which, like the length scale, have the ability to slide up and down along the side grooves of the right column.

Screws 39 serve to control the nonius.

Each of the nonius from the back side of the right column 35 has a C-shaped ebonite trough 40 with a C-shaped cross-section (FIGS. 5 and 8) rigidly attached to it. A few millimeters above the nonius nonionic binding zone of the ebony tolob the latter has a metal contact 41. With internal the sides of the contact protrude into two fifth widths of the cross-section of the chol; from the outer, it has a terminal for supplying the electric wire. A metallic polished rectangular parallelepiped 42, which slides freely along the inner upper part of the chute and is always resting on the inner contact protrusion under the action of gravity, descends from the inside contact protrusion.

The length indicator 22 (Fig. 3, 5 and 9), in addition to the frame with the tensioned band on the front side of the right column, has two contacts on the back side of the right column: left 43 and right 44, which, when lifting the pointer, freely enter the slots of the corresponding and in contact with rectangular gliding parallelepipeds, they close the current through the corresponding contacts of the chutes of the magnetic vibrators (not shown in the drawing), which serve to determine the sound of the moment of contact by sound.

Since the cuts of the blackslap occupy two fifth parts of the crosshead width opposite to the contact protrusion 41, the direct contacts of the blackhead and pointer contacts, which have a gap of one fifth width of the blackhead section, do not touch each other. Therefore, the closure of contacts can occur only at the moment of contact between the pointer and the parallelepiped on one side, the parallelepiped and the zholob contact on the other. At the slightest deviation of the pointer 22 in one direction or the other from the moment of closure, the latter is violated.

With a sufficient parallelepiped length and a small gap between the inner surfaces of the goat and the lateral surfaces of the parallelepiped, the accuracy of the length marking with the help of contacts is very high.

To set a convenient angle of the length scale relative to the plane of the drawing right, the column, together with the pointer, can be turned to the right and left side. This is possible due to the slot in the length gauge that coincides with the circular arc described from the center of rotation of the column.

In addition to the pointer and nonius contacts, the device has two more contacts 8 located on the upper

the parts of the bed 2, which are closed by means of the contact 46 of the left lever 4. Depending on the position of the latter, the upper or lower contact can be closed. Both contacts are isolated by an ebonite cylinder 49 (FIG. 4) from the spindle 47 and ebonite rings 48 from the side walls of the frame. The contacts themselves are metal cylinders mounted on ebonite.

The closing contact 46 on the lever 4 (Fig. 2) is formed from two brass plates (upper and lower), isolated from the lever 4 by an ebonite coupling 51 and electrically connected to each other by screws 52 serving also for tightening the coupling on the lever (Fig. 4 ).

The purpose of contacts 8 and 46 is to signal the sign of a definable quantity, which will be discussed in more detail below.

At both ends of the long arms of levers 3 and 4, there are cups for weights on the right and on the left side. With a balanced system of levers, the load on the left pan of the scale means the compression of the part placed between the jigs, the load on the right pan - tension.

On the left side there are not one, but two cups — the top 11 and the bottom 45. Together with the stand 50, the bottom cup is designed specifically for partial automation, but it can also be used as an element to facilitate measurement in the absence of automation.

Before starting the testing of a batch of bellows, the following preparation was made: balance the weights without weights on all three cups of the scales with the screwed attachment to the upper cartridge 13; the zero division of the length scale is combined with the pointer strip at the moment when the planes of both devices, between which the length of the bellows is measured, are touching. This is achieved by pressing pieces of metal in both devices with a thickness equal to the thickness of the bellows material. Then, a ring with a thickness of exactly 10 mm is placed on a clean (not occupied) end surface of the lower fixture's clamping nut, after which the lower fixture is lifted with a tongue until the upper end surface of the ring contacts the clean (not occupied) end face of the upper nut. devices while maintaining a zero (equilibrium) equilibrium indicator. When, thus, the distance between the surfaces defining the length of the bellows becomes 10 mm, the movable length scale 31 is set so that the risks of 10 mm corresponding to 10 mm coincide with the strip 33 of the indicator. Then lower the lower fixture with the handwheel down to failure and remove the ring. The left no-nius 37 is set to a length equal to the value of 1, and the right nonius 39 is set to a length equal to the magnitude of L, which were discussed above. The length of the L strip of the pointer marked with the right-hand Vernier is set by rotating the handwheel. The right contact of the pointer 44 and the right nonius parallelepiped are brought into contact by raising or lowering the ebonite rod 53, on which the pointer’s contact is secured (the correct lifting is judged by the vibrator’s non-stop sound) and fixed to the marked length of the LN strip pointer. The left pin 43 of the pointer is brought into the parallelepiped of the left nonius in contact and secured with a screw 54. Test the correctness of the preparation made. Lower the weight of 55 weight equal to

SrB

the magnitude

KG on the lower cup 45 left scales.

This completes the preparation.

The test of the bellows (or spring), i.e., the determination of the quantities a and b is carried out as follows.

Install the bellows and stand, wrap it so that it is rigid

fastened with both fixtures.

The right contacts, which fix the length L, are brought into contact. The moment of contact is judged by the sound of the magnetic vibrator that is not ceasing.

Balance levers with weights.

Weights are recorded, and if to balance the weights they were placed on the left (upper) weighing pan, i.e., they were added to the weight of the weight previously placed on the lower weighing pan, then the plus sign (- {-) is assigned, but if weights were placed on the right cup, i.e., subtracted from the weight of the weight previously placed on the left cup, is attributed to the minus sign (-). The recorded weight of the weight is b. Next, put on the lower left cup 45 second weight 62, by weight

SRB equal to the value - | - kg.

In this case, obviously, the additional weight on the left pan of the scale will be equal to

СрБ .iCpA Ср Б СрА -2 2

KG

The left contacts, which fix the length of the LHO moment of contact, are also brought into contact are judged by the sound of the vibrator. Balance levers with weights. Record the weight of the weights, also assigning a plus sign (+) to it if it was necessary to place the weights on the left pan of the balance to balance, and a minus sign (-) if the weights were placed on the right pan.

The recorded load is the value of a.

The springs are tested in exactly the same way, only the difference between the spring test and the bellows is that if the existing aneroid spring is always compressed in the working position of the aneroid (as the length changes from LH to L, then the bellow is in a compressed state in the other way, it’s necessary to have special tools for the bellows

it with tensioning and compressing elements at the time when the spring does not need it.

For cases when it is required to remove the characteristics for compression and tension for springs and for cases of any other forms of bellows (and springs), it is necessary to have special tools that are screwed into the cartridges before testing. Such devices can have a whole set.

The apparatus can serve not only for the special cases discussed above of testing bellows and springs for aneroids, but also for testing the elasticity of any other springs and elastic systems where compression and stretching are required to be performed simultaneously and separately.

To facilitate the determination of the required values of a and b to eliminate the possibility of an error, raising and lowering the weights 62 to the lower left cup with a weight equal to

CpA

SrB

in the presence of contacts can be done automatically.

For this purpose (Fig. 10), one end of the lever 56 that swings on the axis 57 is connected to the stand 60. The other end of the lever 56 is connected to the rod 58 of the piston 59, In both cases, the connection is through rods 60.

The direction of movement of the stand 50 is provided by three guide rods 61. A weight 62 is equal in weight to the ASCEAL.

rank -2-; - kg, supported by three columns 63, rigidly fastened to the base of the stand 50, which has six holes: three for reinforcing the columns 63 and three for passing the guide rods 61. These holes form a regular hexagon, and every three holes separately - right triangles.

In the bottom cup 45 and in the weight 55 SrB

weight equal to - - kg, there are three

openings for free passage of columns 63.

Thus, if current is applied to the terminals M and ЖЗ of the electromagnet 64, then, due to the attraction of the iron rod 65, the stand together

„, -P SrA SrB with a weight of 62 weighing in kg

rises up and on cup 45

SrB

only a weight of kg will remain.

In order to lift smoothly, the air is supplied to the increasing upper volume of the cylinder 66 through a narrow orifice, the cross section of which is controlled by the valve 67.

When the current is turned off, the stand 50 smoothly lowers the weight of 62 weights in

SrASrB

- 22 the lower cup 45, and itself under the force of gravity sits on stops below the equilibrium level in which it is shown in FIG. 10, left in such a way on a load 45 weight in weight

CpA

  tour

2

In order to avoid the influence of the magnetic field of the electromagnet 64 on the equilibrium state of the levers, the magnet must either be far enough away or secured, or the balance system must be made of non-magnetic materials.

The circuit of electrical inclusions is shown in FIG. 1. It M and Zhz - terminals of the electromagnet 64 ,. and the " 2 and " are the contacts of the stand 50, the location of which is schematically indicated in FIG. 10. As can be seen from FIG. 10, fixed contacts n or 2 are closed by a moving contact n, when there is either only a load equal to

weight-f - kg, or only load, ravSrA

kg, K - contact now by weight

left lever 4, closing the contacts: KI - in its upper position and Afg - in its lower position; Y - left contact pointer; W, is the right contact of the pointer; L - the left contact of the nonius and H - the right contact of the nonius.

In addition to these designations, the diagram shows signaling devices located for the value of a in the upper part of the circuit, for the value of b in the lower part.

For each value, the signaling device consists of four elements: three light and one sound. Audible and one light have two common terminals 1-1. This is a magnetic vibrator B and a light image of a measured quantity a and b. Two other light elements, depicting a sign that should be assigned to the measured value, have two independent terminals 2 - 2 and 3-3 each.

From this scheme, it is clear that when the contacts of UA and // ,, are closed, which corresponds to the length L, the current simultaneously passes into the light detector for value b, into the magnetic vibrator and the electromagnet.

Due to the passage of current into the electromagnet, the opening of the contact r and f immediately occurs, and then a smooth rise of the stand. While the stand rises, the current cannot pass through any of the 4 contacts / C closed by the left lever until the sub-rate lifts the additional weight 62 from the bottom left cup.

SrASrB

in and -s- kg and contact n not

closes the contact n. When the contact n closes the contact n on the left bottom lash 45, there will be a weight, a surplus equal to - kg, and in this way the upper and lower position of the left lever 4 will mean that weights should be put on the left or right lash to balance levers, i.e. plus () or minus (-), be assigned to value b, which is indicated by the light signal.

A similar reasoning takes place when closing the contacts Y and // 1, marking the length L.

Thus, with all the compounds listed in the scheme, determining the values of a and b is as follows:

1) a sylfoa is established;

2) one of the contacts defining one of the extreme lengths of the aneroid is brought into compression;

3) a light signal in the passport of the test piece is recorded designation of the measured value and its sign;

4) levers are balanced;

5) the amount of load balancing the levers is recorded in front of the recorded mark;

6) another contact is brought into contact.

Thereafter, steps 3, 4 and 5 are repeated.

The subject matter of the invention.

Claims (3)

1. Instrument for testing springs and bellows for selecting them for aneroid bellows, using lever weights and a linear strain indicator, differing in the use of two lever weights associated with the spring or bellows associated with the test spring or bellows, some of which are used to determine positive and others negative voltage deviations from half of the total tension of the bellows and the spring corresponding to a given aneroid box characteristic. 2. The form of the device according to claim 1, characterized in that, for the purpose of automatic loading and unloading 45 weights with an additional weight 62, which balances half the difference of the voltage of the aneroid box, respectively, two points of its characteristics, 62 is equipped with a piece 50, jointed a system of levers with an electromagnet 64j 65 and with a retrofit absorber 66. 3. The form of the device according to PP, 1 and 2, characterized in that the weight 62 is connected with the stand 50 by the legs 63, passed through the holes in the cup 45 and in the weight 55. FIG. Sh  f al f f fcAL4 FIG. four fip5  , fig.i