DE1201085B - Instrument for measuring a factor that is a function of variable pressure - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. σ .:

GOIl

German KL: 42k -14/03

Number: File number: Filing date: Display date:

B66471IXb / 42k March 22, 1962 September 16, 1965

Instrument for measuring a factor that is a function of a variable pressure

Applicant:

The Bendix Corporation, Detroit, Mich. (V. St. A.)

Representative:

Dr.-Ing. H. Negendank, patent attorney,

Hamburg 36, Neuer Wall 41

Named as inventor:

Carl Einar Johanson, Davenport, Ia. (V. St. A.)

Claimed priority:

V. St. v. America March 24, 1961 (98 117) - -

The object of the invention can be applied to measuring instruments for any, of one or Apply a factor dependent on several variable pressures, especially in the case of measuring instruments for various aerodynamic factors based on one or more pressure measurements such as the altitude, the mach number, the aerodynamic speed, the equivalent speed, etc. These applications are not limited to aerospace engineering. ok

Numerous instruments not only used in aviation are based in their mode of action on the Measurement of one or more variable pressures, with the help of manometers with a deformable Membrane, e.g. B. aneroid capsules or Bourdon tubes 15 can be measured. The output size of this Instruments are usually in the form of a twist on a shaft.

So with an altimeter, the twist is the
Output wave indicating altitude, a function 20
of the static atmospheric pressure that is generated by a
Capsule or other pressure gauge element. In a Mach meter, the output shaft twist, which is a measure of the Mach number, is a complicated function of the ratio 25
between the dynamic pressure and the static pressure measured by two different manometer elements. With altimeters

high accuracy, it is necessary to introduce a correction quantity which is a function of the Mach 30 2
number is.

The transformation of the deformation movement device simpler and more economical design to create Manometer element in a twist of the fen, in which the advantages of the above Shaft will be used by a kinematic connection transmission arrangement and that acts, which in its simplest form from a connecting rod 35 should be able to cope with the deformations of the mano-crank mechanism consists. With the complicated meter element according to a predetermined, arbitrary Nature of the law between the deformations of the complicated law with extraordinarily high Ge-manometer element and to convert the twist of the precision.

output shaft and the in aeronautical instruments This task is in an instrument for

The very high accuracy required is such a measurement of a factor that is a function of a simpler Mechanism inadequate. Furthermore, the pressure must be changed, especially one taking into account aero, that the complex mechanisms, dynamic factor that is a function of the statidie the desired function of the input or dynamic atmospheric pressure is automatically, pressure or the inlet pressures, which is equipped with an on changes in the rotating cams employ the deformable pressure gauge differential mechanisms responsive to corrective 45 pressure are connected. element as well as a rotatable shaft that is connected to

It is a kinematic connection in the manner of the pressure gauge element via a mechanism Connecting rod cranks with a stationary or essentially connected, which the deformations of the Manolichen stationary correction cam known, with which the meter element converts into rotations of the shaft, It is possible to create deformations after a pre-50 with the mechanism one at one end with the to transform the written relationship. Manometer element connected part, its other

The invention is based on the object of placing one end on a shaft rotating at an angle.

3 4

sliding arm with the interposition of a formations, which is a function of the on the capsule

variable transfer ratio enable - onerous pressure are, according to a prescribed -

the control disc with the sensing element attached to it, a law in rotations of a shaft 11 is reversed

acts, characterized according to the invention, are converted. At the free end of the capsule 10 is that the mechanism for changing the ratio 5 attaches a swing arm 12, which here consists of a strip

between the angle of adjustment of the arm and fen with a certain elasticity. The free

the deformation of the pressure gauge element a rotating end of this strip 12 is on one on the shaft

bar eccentric member is articulated on the lever arm 13 attached to the scanning member. This attachment

contains consolidates, and that the control disc is done separately kung via a mechanism that follows in the folhaltert is. io will be described in more detail.

This measuring instrument can also be used at the free end of the swing arm 12 is a

experience going training of its items. This axis 14 is soldered perpendicular to the direction in which

can consist in the fact that the free end of the capsule 10 is deformed. These

. , _ ,,.,. ,. _,,,,. , Axis can rotate freely in a first opening,

the eccentric link in the articulation _{which is located in the cylindrical} block 15,

between the part and the arm switched _we j _{cher that eccentric element forms in one}

^WI 'another parallel hole in this one

the sensing element of the eccentric link block rotates a second axis 16 which passes through

goes out; a soldered bimetal rod 19 is extended,

the control disk on a second deformier- ao the with its other end at an eccentric one

bar pressure gauge element is mounted; Point of a cylindrical block 20 is attached, the

the second gauge element rubbing thereon in a bore in the end portion of the arm

variable pressure responds like the first 13 can turn.

called manometer element; The connection comprising the bimetallic rod 19, the second eccentric second manometer element with the shaft * S block 20 and the arm 13 is connected via a further mechanism, is already the subject of an earlier proposal which includes a component that therefore forms ^{UQ d with the second} no part of the present invention manometer element is connected, as well as a manure. This connection has the task, through the angularly displaceable lever, which is able to rotate the shaft to rotate the block 20 with the help of a suitable, the lever extends essentially 3o tool opposite the arm 13, the position of the borrowed opposite to the arm; Bending plane of the bimetallic rod 19 as a function of changing the second manometer element to a changeable temperature and thus responding to the calibration of the Indian pressure, which can be facilitated by the instrument. In order to distinguish the description of the pressure to which the first mano-mode of operation of the subject invention responds to vermeterelement; In the following, the connection between the second manometer element via a further axis 16 and the arm 13 as a rigid and immovable mechanism with a second shaft is assumed to be changeable. . . ".
is bound, with the further mechanism a _J ^An _A ^a * ^m eccentric block I ₃ is perpendicular to with the second manometer element and a ^de . ^{n axes 14} ™ ^{d 16} . ^{a ΑΐΐΙ} \} 7 attached, which at an angularly displaceable piece connected to its lower end comprises a parallel to the said final part and the two shafts the axes extending finger 18 This finger at both inputs of a differential mechanism lies on the active edge of a cam 21, press, whose output forms the output of ^the home ^dl ^ ^Fo ™ a profiled disc and has representing at struments · ^{EMEM solid Tra} 8 ^e r is fixed. The finger 18 becomes. ,, '"..,. . 45 by the elasticity of the swing arm 12 against which the arm and the piece at a common _{profile of the cam ß}

Axis are articulated and the corresponding _{As soon as} ^ö _d f _{e K d 10 is deformed}

Adjust shafts via gear; i_ _{by the Pleue} Urbel _K-compound represented by the

the first manometer element is _{formed on the dynamic swing arm 12 and the} lever arm 13,

see air pressure and the second manometer - _the shaft 11 is twisted. For each value of the deforma-

element to the static air pressure response of _{the κ γ ± h for each position of the end of the}

are arranged accordingly. Swing arm 12, gives the profile of the cam 21

These and other characteristics of the invention are said to be about the finger 18 and the arm 17 of the eccentric

In the following, a certain position in relation to the axis 16 is shown on the basis of the drawing at some positions 15

examples of management explained in more detail. It shows 35 and thus on the one hand changes the distance between the

F i g. 1 in side view a first Ausführungsbei- axis 14 and the axis of the shaft 11 and other play for an altimeter, on the other hand, the distance between the axis 16 and the

2 shows, on an enlarged scale, a horizontal capsule 10. The angle by which the shaft 11

Tal section through the embodiment according to rotates for a given deformation of the capsule 10,

F i g. 1, 60 changes over the deformation area of the capsule

F i g. 3 a calibration curve of the altimeter according to a law defined by the profile of the

Fi g. 1 and 2, cam 21 is determined.

4 and 5 show two views of a second example. to clarify the direction, it is in the following in

6 and 7 are two views of a third embodiment of their application to an altimeter,

example. It is well known that the barometric altitude i? _p

The in the F i g. 1 and 2 shown execution in meters as a function of the absolute temperature T,

Example includes a barometer capsule 10, the de- the static barometer pressure P _s and the bottom

5 6

the prevailing barometric _{pressure F 0} from the slip, which is based on the initial pre-stresses of the

chung: both swing arms 32 and 40 and the capsules 30

_ P ₀ and 40 go back. These biases result

H _p - 67.4 i log-. _during assembly. During the operation of the

^s 5 device, however, these two advantages

Since it is extremely difficult to measure the temperature tension torques completely or to an accuracy of one door T , it is customary to set the temperature of the standard atmosphere, which is used to counteract the finger 37, in this small resultant torque of selectable size Use the one that drops linearly from 0 to 10 500 m and press cams 38. This resulting rotation then remains constant up to 32,000 m. Due to the assumption made simpler by the cam 38, however, this ver io moment results in a relative rotation of the eccentric 33 between an altitude of 12,000 and 15,000 m with the customary barometric altimeters, as is the case with the first exemplary embodiment the degree of deformation of the capsules. As error to be eliminated. The F i g. 3 shows, drawn in an extended manner, the relative displacement between the cam 38, the angle of rotation of the exit 15 and the finger 37 in this exemplary embodiment of the output shaft of a conventional barometric altitude - from the simultaneous expansion of the two cap knives as a function of altitude. This curve shows that it is 30 and 39 dependent (assuming that these two capsules are clearly recognizable between 12,000 and 15,000 m due to changes in the indentation that are deformed at the same pressure due to the error mentioned), the length can decrease. However, it is possible to suppress this error by selecting a profile of the cam 21 corresponding to the active profile of the cam to be twice as large as in the case of the fixed cam of the first. The path used in the measuring device according to the exemplary embodiment, and thereby the accuracy of the invention, can be greatly increased.

subject. The calibration of the instrument in relation to another, to the solution of a complex one special parameters of each barometer capsule from a series used in height measurement technology is thereby considerably simplified. The exemplary embodiment of the invention is shown in FIG. 6 The profile of the cam 21 does not need to be shown with a and 7. As is well known, every measurement of the to be manufactured with a very high degree of accuracy. The static pressure on board an aircraft with The final accuracy held is subject to an error for a given result, which is caused by the accuracy of the speed of the cam, the greater the dynamic phenomena back ratio that is generated the distances between the axes 16 goes. This speed-dependent error takes and 18 on the one hand and the axes 16 and 14 on the other - at supersonic speed, in their limit range on the other hand (Fig. 2). This ratio can easily increase the travel height for several years without reducing the mechanical speed of the airliners to influence the device. In the 35 borrowed value. There are devices known that it In practice it is quite sufficient to simply allow the cams to correct this dynamic error, by punching without any special post-processing so that it can no longer be produced on the height display. The manufacturing costs of an instru- ment. The device according to the present invention According to the invention, this essentially allows this task to be performed degraded. 40 switching of the dynamic error to a similar one

The F i g. 4 and 5 show a further embodiment as in the known devices, however

example that differs from the one just described as being much more economical and expedient

differs in that the cam does not loosen firmly.

ordered, but even as a function of a chosen one. 6 and 7 is the output shaft with 88

Factor is movable. 45 of the altimeter. This wave forms the

Like the first embodiment, the device comprises an epicycloid differential gear, Example of a capsule 30, on which the swing arm desen first input through a conical planetary gear 32 is attached. This swing arm is formed with a 56 that is placed on a shaft 57, Axis 32 a applied to an eccentric 33, which is and its second input through a straight PIaseinseite rotates about an axis 33 α, which forms a bi- 50 netenrad 86, which is freely on the starting metal rod 34 extended, which runs on one of the shaft 88 and that via a pinion 85 of one Gear shaft 31 supported arm 35 is attached. How shaft 84 is driven. That with a (or more In the first exemplary embodiment, the eccentric (eccentric) tapered satellite wheels 87 have meshing cones 33 an arm 36, the planet gear 56 connected with a finger 37 rotates around a fixed plumb line is, which on the profile of a cam 38 55 right to the shaft 88 lying axis and combs in white is. However, this cam is not in ter with a conical ring gear that is a part a fixed invariable distance from that of said planetary gear 86 forms. This on Axis of the shaft 31 is arranged, but is known planetary gear can be by any other free end of a manometer capsule 39 carried. whose equivalent gearboxes are replaced. On this second capsule 39 is a vibrating 60 Die, the two inputs of the differential gear arm 32 of corresponding second, elastic oscillating-driving shafts 57 and 84 carry two pinions arm 40 attached, the via a bimetallic rod 41 and 55 and 71. These two pinions are with two teeth eccentric adjustment block 43 engaged on two rims 54 and 70, which both revolve around th arm 42 is articulated, which can rotate the arm 35 against the same fixed axis 51. The set of teeth is also attached to the shaft 31. 65 wreath 54 is supported by a rod 53 (made of bimetal

The device according to FIGS. 4 and 5 can stand) with an elastic swing arm 52

particular advantage that the shaft 31 is separated from two, the one at the movable end on

opposing elastic torques under the static pressure responsive capsule 50 loading

is consolidated. The ring gear 70 is in turn via an axis 65, an eccentric 64 and a bimetal rod 62 connected to an elastic swing arm 63 which is attached to the movable end of a capsule 60 that responds to the dynamic overpressure and its interior for this purpose via a Tube 61 is connected to a total pressure wave (such as a pitot tube). One on the eccentric 64 Attached arm 72 rests with a finger 80 on the profile of one on the capsule 50 for the static view Pressure attached cam 81.

The mode of operation of this device corresponds approximately to the device described above. The deformations of the capsule 50 for the static pressure act via the swing arm 52, the ring gear 54, the pinion 55 and the shaft 57 directly to the first input (planetary gear 56) of the differential gear. This first input is thus driven according to a factor that is a first Represents approximation of the height. The static capsule 50 and dynamic capsule 60 also function over the cam 81 and the eccentric 64 together to the ring gear 70 and over the elements 71,84, 85 the planetary gear 86, which forms the second input of the differential gear, correcting To issue angular thrusts, which add algebraically to the rotation of the planetary gear 56, so that the output shaft 88 rotates through an angle which, however large, the Mach number is an exact measure of the altitude of the aircraft.

In this embodiment, the profile of the cam 81 runs according to the function between the Altitude correction and the Mach number, so that the desired correct mode of action is ensured.

In addition, two electrical contacts 91 and 92 can be arranged on the shafts 57 and 84, those for a given value of the Mach number or for a given value of the equivalent speed, depending on which of these two values is reached first, emit a warning signal and / or trigger a certain effect.

The use of an elastic swing arm 12, 32, 40, 52, 63 in connection with each of the deformable capsules leads to a special one here Advantage as it allows the curvature of the paths of the various cams in the Reduce areas of the slope change. However, it is also possible to replace the elastic ones Swing arms use rigid swing arms attached to both ends in the usual way are hinged.

The eccentric element controlled by the cam can be at a suitable point on the mechanism be arranged, which connects the deformable capsule with the arm on the shaft, about at the junction between this arm and the swing arm or at the junction between the swing arm and the capsule. Further, as is known per se with such mechanisms is, the relative position between the cam and the follower can be reversed so that the Cam is firmly connected to the eccentric and the follower element takes the place of the cam.

Claims (10)

Patent claims: 1. instrument for measuring a factor which is a function of a variable pressure, 65 in particular an aerodynamic factor, which is a function of the static or dynamic atmospheric pressure, with a deformable manometer element, which responds to the variable pressure, and a rotatable shaft, which is connected to the manometer element via a mechanism, the deformation of the manometer element in rotations of the shaft, the mechanism comprising a part connected at one end to the manometer element, the other end of which acts on an angularly displaceable arm rotating the shaft with the interposition of a control disk which enables a variable transmission ratio and a sensing element lying thereon, characterized in that the mechanism a rotatable eccentric member (15, 33, 64) for changing the ratio between the adjustment angle of the arm (13, 35, 70) and the deformation of the pressure gauge element (10, 30, 50) attached to the scanning member (17, 36, 72) contains and that the control disk e (21, 38, 81) is supported separately. 2. Instrument according to claim 1, characterized in that the eccentric member (15, 33, 64) switched into the articulated connection between the part (12, 32, 63) and the arm (13, 35, 70) is. 3. Instrument according to claims 1 and 2, characterized in that the scanning member (17, 36, 72) starts from the eccentric member (15, 33, 64). 4. Instrument according to one of claims 1 to 3, characterized in that the control disc (38,81) is mounted on a second deformable pressure gauge element (39, 50). 5. Instrument according to claim 4, characterized in that the second pressure gauge element (39) is responsive to the same variable pressure as the former pressure gauge element (10). 6. Instrument according to claim 5, characterized in that the second pressure gauge element (39) is connected to the shaft (31) via a further mechanism, which is a component (40) which is connected to the second manometer element (39), and an angularly displaceable one Lever (42) which rotates the shaft (31), the lever (42) being essentially opposite to the arm (35). 7. Instrument according to claim 4, characterized in that the second pressure gauge element (50) is responsive to a varying pressure different from the pressure to which the first pressure gauge element (60) responds. 8. Instrument according to claim 7, characterized in that the second pressure gauge element (50) is connected to a second shaft (57) via a further mechanism, the mechanism a connector (52) connected to the second manometer element and an angularly displaceable piece (54) and the two shafts (84, 57) actuate the two inputs of a differential mechanism (56, 86, 87), whose output (88) represents the output of the instrument. 9. Instrument according to claim 8, characterized in that the arm (70) and the piece (54) are articulated to a common axis (51) and the corresponding shafts (84,57) over Adjust the gear (71,55). 10. Instrument according to one of claims 7 to 9, characterized in that the pressure gauge element (60) on the dynamic air 10 pressure and the second manometer element (50) is responsive to the static atmospheric pressure. Considered publications: German Patent Specifications No. 442471, 620845; German interpretative document No. 1003 459. For this purpose, 1 sheet of drawings 509 687/194 9.65 © Bundesdruckerei Berlin