DE1665788A1 - Pressure switch - Google Patents

Description

SUNDSTRAND CORPORATION 2531 Eleventh Street, Rockford, Illinois, V.St.A.

Pressure switch < The invention looks at pressure switches and in particular

others to a hydraulic pressure sensitive switch to display a pressure status above or below., of a certain value.

Pressure sensitive switches are commonly used in actuators of constant speed used in aircraft to indicate when the hydraulic 'delivery pressure for bestiran hydraulic control elements has reached a permissible high value, and also to indicate that the Abtriebedreh.-.

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number is in a permissible range " so that the drive delivers the required power to the shaft of a synchronous generator ** coupled to the drive, which forms the electrical power supply for the plug-in." So far, the switches used for this purpose consisted of a switch mechanism, electrical Wecheelkontakte in a bistable arrangement and a hydraulically actuated piston which responds to the hydraulic pressure and actuates the switch mechanism at a certain pressure. The use of these switches has resulted in serious disadvantages insofar as in some applications they were relatively stable and unreliable due to the strong currents flowing through the contacts, the vibrations in the environment and there. the temperature and pressure fluctuations have led to a relatively short contact life.

The object of the invention is to create a bistable pressure-sensitive switch which reports the above-described disadvantages of the previously known pressure-sensitive switching devices. The subject of the invention is therefore in particular a pressure switch with a variable inductance to control an external device / means for changing the value of the inductance -: with a permeable Qlied that is connected to the '.,'.

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variable inductance between a first position, in which the impedance of the variable inductance is low, iet and a second position is movable, In which the impedance of the variable inductance is high, and a pressure sensitive organ through which <& s permeable link between the first and the «wide Position can be moved *,

Further objects and advantages of the invention will become apparent from the following description in conjunction with the accompanying drawings Drawings and ewar show:

Flg. 1 a longitudinal section of a pressure according to the invention * sensitive switch;

2 shows a longitudinal section of the pressure sensor according to the invention Switch according to Pig · 1, but rotated by 90 °;

Fig. 3 is a cross-sectional view taken on line 3-3 of Fig. 1, which. the anchoranci'dmang shows;

Fig * H shows a cross section essentially along the line 4-4 ^

■., ·· - ··. · «In Fig, Z ₉ which part of the movable anchor .. _Λ

arrangement shows and

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Pigc 5 a ^ schematic representation of a control circuit « the pressure-sensitive in the case of the invention Switch mechanism is used »

The following description is given, for example _Å and not to be construed.

The in ZeJAhnungen waa particular in Pig, 1 and 2. * superscript * »rflndungsge" ttsse pressure sensitive Schaltenoecha "nisatus Io has a substantially cylindrical main" casing-Il and an end closure 12, which in the f a Em * "of the solidary housing 11 can be set up «The Schaltsr Io is elneetzbar in a housing 13, which is only partially shown in Pig. 1 and which forms part of the housing of a drive with a constant speed. The Oehluoe 13 has a stepped approach 14, which extends see within the Antrlebegehfiuses. The holder Io can be inserted into the housing 13 and into the extension lh from outside the drive housing.

Of the. pressure-sensitive holder Io also has a coil former l6 ₉ which is fastened in housing part Ii and connected to a suitable electrical current source through lines 18 »

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an armature 19 and a pressure-sensitive actuator 2o is connected, which responds to the pressure medium in a chamber 21 "which is formed by the extension 14" around the armature 19 in one of its bistable positions to change the impedance of the coil formers 16 see below * because of which either a low impedance or a high impedance is generated in the coil · The chamber 21 is hydraulically connected to the hydraulic control within the drive housing ₈ so that the hydraulic pressure medium is fed to the chamber 21 «

If there is a pressure above a certain value in the hydraulic chamber 21, the pressure-sensitive actuation mechanism moves to the left, whereby the movable armature 19 is also moved to the left, so that the air gap 22 closes and the Soheinwider @ tani of the coil 16 is increased to a relatively high value. This high impedance through a suitable control circuit, described in more detail below, serves as an indication that the ur-ik in the edge 21 is above the certain value. If, on the other hand, the pressure in the chamber 21 falls below the certain value, the actuator moves regulation 2o under the effect of a suitable load

elements close to the right, whereby the armature 19 away from the coil « t-twegt, and «generated in a relatively large air gap 22

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which raises the impedance in the coil 16 and thus creates a wide stable state in the control circuit » which indicates that the pressure in chamber 21 is below the specified value »

The following are the working elements of the invention pressure-sensitive switching device described · The housing part 11 has protruding lugs 25 but fastening the switch assembly in the desired position in the drive housing 13 on. The end spine 12 is essentially cylindrical and can be inserted into a central bore 27 in the main housing part 11 · An insulating plug inserted into a central opening in closure 12 holds the electrical ! lines 18 in their position «Suitable electrical lines connect the lines 18 to the coil 16. The encroachment air 12 has forked projections 29 and 3o, the aa be * most of them can be seen from flg. 3 and which extend below a shoulder 32 in the bore 27 and bear against it. The forked Vor jumps 29 and 3o flankleren magnetically permeable layered core 34 which is part of the Forms bobbin 16, by lock 12 is in Qehfiusetell 11 held by a suitable snap ring 36, which the Projections 29 and 3o against the shoulder 32 hlls. around the spool 16 with the beast on the anchor 19 keep in alignment su, slod Aiseflttohtungsetifte 38 provided

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The coil assembly 16 is a device of more variable nature Inductance with the bistable way either a state with a low impedance or a state with a high apparent resistance can be achieved substantially U-shaped layered magnetically permeable Part 34 formed · Part 34 sltst with closer Fit in a central opening in the coil 4o and has leg points 42 and 43, the ends 44 of which are part of the Limit air gap 22 * As can be seen, »changes a Movement of the armature 19 with Besug on the permeable part 42 the path of the force lines, whereby the apparent resistance of the Spy « len arrangement 16 is fired "

The Anke? 19 essentially has eln @ n! U-shaped permeable Part 5o, made of layered ferron & gnetleehen ' Plates similar to the core 34 can be made. Bin in essential U-shaped retaining element 52 surrounds the happening * teten learn or anchor 5o and is attached to this. The anchor 19 surrounds a shaft or rod 54, which extends through the retaining element and the anchor 5o * The shaft 54. wears a permanent magnet ring 56. The anchor 5o, the holding * element or the carrier 52 and the magnetic ring 56 are on de «shaft or rod 54 by an enlarged part 57 a »front end of rod 54 held, which serves the»

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to load the ring 56 against a suitable shoulder 58 on the rod or on the shaft 5 *. In its central part the casing Il besitst a partition Bo with a "substantially rectangular slot 61 for slidably receiving the retaining» elements 52 ₀

The actuating arrangement 2o serves to move the layered core 5o out of its position shown in FIGS. ste position is referred to, move into a position su, in which it rests on the layered core 42 and which is called "wide Position can be designated · The actuation arrangement has a stepped, substantially cylindrical piston guide 65, which sltst in the right end of the housing 11 and through a suitable ring 67 is held in it · A central hole 68 in the piston guide 65 serves for the sliding reception of a piston 70, which is designed with an enlarged head 71 at one end. In the right binding position of the piston 7ο is the enlarged head 71 on an annular Projection 72 on the piston guide, which serves as a stop for the piston

The right end of the piston 7o is the pressure of the hydraulic Exposed to pressure medium in the chamber 21 so that it responds to it

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centered in the piston 7ο for receiving the extended end of the shaft or the rod * 54 is provided.

A suitable backlash connection 76 is provided between the piston 7o and the armature 19 in order to regulate the closing forces exerted on the armature by the actuating element 2o Piston 7o is attached and see through an elongated Schiit 79 each extends in the anchor shaft 5 *. A Sohraubandruok spring So, located inside the piston bore 75, normally loads the shaft 54 of the piston 7o in a position in which the pin 71 rests inclined ₂ at the right end of the slot 79 »wl · In Pig» 2, where it is extended further of the shaft 54 from the piston bore 75 is prevented as follows from the following, the spring 8 serves the desired closing force between the movable armature 5o and the fixed "tehendea Κ": - η 34 independently from the force of the hydraulic pressure acting on the Keloeis T ©.

The actuator assembly also includes a screw pressure button 9c on which "they? I esgen a shoulder 91 1st O * htuset ^ li 11 to move the piston 7o to the right in its su «, Return or load first position * Dl · Fed · * 9o

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is also supported against an essentially cup-shaped spring holding element 93 with a flange part 91 which forms a seat for one end of the spring 9o. The holding element 93 has a central opening 94 which freely receives the shaft 5. The spring 9o therefore loads the piston 7o into its retracted position through the holding element 93 · The spring 9o is selected with reference to the surface area of the side of the piston 7o loaded by the pressure medium, that * at a certain pressure »sB of 7 kg / cm ² (loo psi) in the chamber 21 the piston 7o is moved to the left against the force of the spring 9o "whereby the gap 22 is closed" and. inversely burdened »if the pressure then falls below the specified»

th value drops, the spring 9o moves the piston 7o to the right,

»Through the gap 22 is opened.

The holding element 93 has projections 95 which flank the seldom of the armature holding element 52 and which serve limit the movement of the piston 7ο to the left. if If the piston 7o moves to the left and the holding element 93 rises, the projections 95 come at the end of a countersink 97 in the housing part 11 on the plant »whereby a further movement of the piston 7o is prevented. The movement restrictions of the piston 7o passing through the shoulder 97 and the Schul

ter 72 are formed on the piston guide »are selected in this way» because the piston 7o emerges from its sloping position in FIGS. 1 and 2.

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Position to its deny position moves, in which the spring seat projections 95 arrive at the shoulder 97 by a greater distance to the plant ala necessary 1st to a contact "wipe the armature 5o and the core _and bring about 42 Therefore, the piston performs a grSssere movement ale Anchor 19

In the housing parts IX and IH there are suitable drainage edges 1 © 2 uncü lö3 for draining leakage fluid from the MeohanisiauB intended. It should be mentioned here that the

Channel Io2 draining liquid to a liquid container

Ströat within the drive housing a 13. To avoid reading of liquid from hydraulic chamber 21 a ring seal Io5 is provided. switch housing 11 and the inside of the approach 1 * see below avoid, another ring seal Io6 is provided, which sits within a suitable annular recess in the circumference of the housing part 11

Dex mentioned Magnefcring 56 is a permanent magnet and serves to Magnetic particles floating in the hydr & ullech ^ n pressure medium to collect “soft” on the piston 7o past the hydraulic

■ ι · & · '21 licks _e This prevents you from looking strange «»

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particles collect in the air gap 22 and the operation or the work cycle of the switch βtüren «

When in operation the pressure in the chamber 21 below the value _t starry holds the preloaded spring 9o 7ο the piston and the armature 19 in the position shown in Figo 1 and 2 position. The resulting large air gap 22 in the magnetic circuit has the stubborn consequence that the coil resistance is low and a considerable amount of current flows through a load resistance R, as in the circuit in Flg. 5 shown. A suitable Hegel or display device loo 1st su «load resistance R ^ connected in parallel · During this operation, the current I ^ is largely determined by the value of the load resistance R. State to be chosen.

If the pressure in the chamber 21 exceeds the certain value, moves the piston 7o to the left against the Load force of the compression spring 9o. Before the projections 95 come at shoulder 97 in housing 11 eur attachment, comes the anchor core 5o at the ends of the legs of the core 34 in the fixed coil assembly 16 eur plant, whereby a

f · axial movement of the armature 19 is interrupted. The one on the

Piston 7ο acting hydraulic pressure stops, however

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the actuating arrangement 2o is moved to the left until the projections 95 come to rest on the shoulder 97. During this movement, the lost motion pin 77 leaves the right end of the slide 79 la shaft 54 and takes a floating position in this when the armature 5o on the core 34 When it comes to contact *, the sole & force between these is determined by the compression spring 8o, which acts against the rear end of the anchor shaft 54, and can be selected as desired. " The impedance of the coil arrangement then becomes _{large in comparison with the load resistance R L} , since the air gap 22 is very small and the current I becomes very small, if it is essentially determined by the reactance of the coil. The low "Value of the _{current flowing through the load resistance" R L} changes the bistable state of the "display or control device loo.

Venn bfällt the pressure in the chamber 21, then the predetermined value ", the spring leads 9o the actuating member in the first ·""retracted" position surQek in which the recirculation <fes Ankert tu the position shown in Figure "1 and 2 take place can"

It is an important feature of the switching device according to the invention The point is that the coil assembly 16 is simple and robust s # in because it does not change linearly with pressure

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To have inductance needs «Instead it is merely required that the Sehalter find a great deal of inactivity Syrian has the open and the closed position.

Another important feature of the invention is that there are no critical oil seals in the switching arrangement required, β ind and the whole mechanism in the liquid can be operated immersed without the disadvantage of working in a liquid electrical contacts occur "

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Claims (1)

T665788 AVIA - 7ft ² ^ = ⁵ ~ October 20, 1966 Patent claims: 1. Pressure switch, characterized by a variable Indui ^ vicät £ ur control of a ftueseren device » Means of changing the value of the inductance, whatever is formed by a magnetically permeable member which does not affect the "variable inductance" a first position "in which the impedance of the variable inductance is low, and a" wide one Movable position »in which the impedance A · variable inductance high 1st, and a pressure-sensitive. lichee organ / 'through which the permeable limb between the / first and the second position are moved can ο 2ο pressure switch according to claim 1 »characterized» the mentioned pressure-sensitive organ at a pressure above a certain value responds »to the permeable Move the link into one of the positions below »and respond to a pressure below the specified value» 20tt1S / O25S 8AD ORIGINAL AYIA - 7 » us the [permeable link in all the others mentioned To move positions 3. Pressure switch according to claim 1 or 2, characterized in that the pressure-sensitive member has a member which is loaded in the said first position «a linkage connects the pressure-sensitive member with the permeable member and has a lost motion connection with the permeable member, ma a elastic element loads the permeable member away from the pressure-sensitive organ, so that the closing force at the variable inductance does not significantly change by an additional path of the pressure-sensitive organ mentioned. ■ t. will change. H. pressure switch according to claims 1-3 "characterized by means for Bewegungsbegrensung the pressure-sensitive organs beyond the second position beyond ₄ which pressure sensitive member is movable between the first position and the second position with a way of large 1st necessary, permeable to the Link, »move between the open and closed positions. -16- _AAA 209815 / 025S 16657β8 AVIA - 74 ft 5 «pressure switch according to claim 1, 2, 3 or 4, characterized by a device for collecting foreign bodies »around their accumulation in.dem air gap between the variable To prevent inductance and the permeable member " 6 · Pressure switch according to claim 5 _S, characterized in that the collecting device is formed by a permanent magnet adjacent to the permeable member « 7 »Pressure switch, characterized by an electrical Switching device with a first and a "wide link, the two of a switch open position and a switch closed position are relatively movable, pressure sensitive means by which the links between the Switch open and the switch closed division moves and which has a pressure-sensitive organ »which is in a first position when a pressure is applied movable below a certain value and into a second position at a pressure above a certain value i * t, means which the pressure-sensitive organ in the load first position, a linkage »which the pressure -17- ι · 200815/0255 _B ad original AVIA - 7 * Connect sensitive organ with one of the switch members, and which has a lost motion connection with one of the members and loads an elastic element of one of the switch members away from the pressure-sensitive organ, no that the SchlleAkraft on the Sehalter is not significantly changed by an additional path of the pressure-sensitive organ. 8, pressure switch according to claim 7, characterized in that the pressure-sensitive element is formed by a piston and means are provided to limit the movement of the piston beyond the position in dispute, the piston being movable between the first and the alternate position is larger than the required _ä move below the Schüiterglieder between the open and the closed position. 9 «Pressure switch according to claim 1, characterized by a housing, wherein the variable inductance is formed by a coil arrangement in the housing, means for supplying a changing. Signals on the coil arrangement, the permeable member can be moved into a first position at a distance from the coil arrangement in order to - ¹⁸ "2O9815 / Ö2SS BAD GRIQiNAL AVIA - imagined to bring about low impedance, and in a post position closer to the mentioned coil arrangement is movable to the mentioned high apparent resistance bring about the pressure-sensitive organ through a Piston is formed, which is slidably arranged in the housing and in this forms a fluid chamber, Means associated with the piston sun moving the permeable Member, a spring that biases the piston in a first position while seeing the permeable Member is in the aforementioned first position, the pressure fids β igkeitekaniBer is so built that it is located in this Liquid above a certain pressure value moves the piston to a wide position opposite to the Loading force of the spring moves when the permeable link is in the »wide position · Io · Pressure switch according to claim 9 »characterized in that daft the means connected to the piston sun moving the permeable member have a linkage with a lost motion connection, means, the permeable member of Load the piston away, the distance between the first and the second position of the piston is greater than necessary is to the permeable link between the first and " ¹⁹ ~ 209815/0255 AYIA - second position su move »whereby the load means between the piston and the permeable member the Force on the latter determine which of these is the coil arrangement burdened »when the permeable oil is in the mentioned second position is * 11. Pressure switch according to claim 9 or Io, characterized by means of collecting foreign bodies »those in the suspended from the liquid leaking from the Flüselgkeitkaamer are. 12 «Pressure switch according to claim 11», characterized in that let the collecting means by a permanent magnet in that Housing adjacent to the piston and between this and the coil arrangement are formed »so that foreign bodies are prevented from »contaminating the air gap between the coil assembly and the permeable member. 13 · Pressure switch according to claim 9 »Io» 11 or 12 »thereby marked »because the mentioned coil arrangement has a substantially ring-shaped coil» the inner * -2o- 20981S / 02SS AVIA - 7 * half of the housing is attached, and a substantially U-shaped permeable link that runs through the aforementioned Coil extends and has axially extending leg parts, the ends of which extend beyond the coil extend and form an air gap with the permeable member. 14 »Pressure switch according to claim 13, characterized in that that the aforementioned first permeable member is an essentially U-shaped anchor, the limb of which see axially extend and the ends of which are adjacent to the ends of the permeable member of the coil assembly, and that he * said housing has an axially extending recess but receiving the first permeable member 15 · Pressure switch according to claim 14, characterized by » that the mentioned piston has an enlarged head part, the shoulder In the mentioned housing on the ■ · .-, mentioned head In the first position of the piston * ur Can come into contact »the piston has an axial bore * has, the linkage has a shaft bsw, a rod has attached to the first permeable member -21- 209815 / 02SS BATH ORIGINAL AVIA - 7 * and is slidable in the bore, the loading means be formed between the piston and the first permeable member by a compression spring in the bore, which the The shaft mentioned above loads out of the bore »the lost motion connection through an elongated Schute * and Pin connection «between the mentioned piston and the Shank is formed. 16 «pressure switch according to claim 15 * characterized by a Spring-ready element attached to the enlarged end of the piston is applied, the spring "which the piston in its first Position loaded "a helical spring is" which sits inside the housing and attaches itself to the mentioned spring * sltselement supports what letstereo forked projection © has «which stop the mentioned piston in the swelten position and see axially extending and flank the first permeable link 17 * Pressure switch according to claim 11 «15 or 16« marked by a permanent magnet on the extended part. of the shaft to collect foreign bodies in the from the Leaking liquid is arranged in the fluid chamber -22- 20 & Ö15 / 0255 BAD OPiGiNAL Blank page