GB2253062A - Potentiometer apparatus for measuring the displacement of a piston in a cylinder - Google Patents

Potentiometer apparatus for measuring the displacement of a piston in a cylinder Download PDF

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Publication number
GB2253062A
GB2253062A GB9203759A GB9203759A GB2253062A GB 2253062 A GB2253062 A GB 2253062A GB 9203759 A GB9203759 A GB 9203759A GB 9203759 A GB9203759 A GB 9203759A GB 2253062 A GB2253062 A GB 2253062A
Authority
GB
United Kingdom
Prior art keywords
holder
piston
cylinder
assembly
potentiometer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9203759A
Other versions
GB9203759D0 (en
Inventor
Helmut Gottling
Rudolf Moller
Ralf Kook
Gerhard Scharnowski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vodafone GmbH
Original Assignee
Mannesmann AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to DE19914105703 priority Critical patent/DE4105703C2/de
Application filed by Mannesmann AG filed Critical Mannesmann AG
Publication of GB9203759D0 publication Critical patent/GB9203759D0/en
Publication of GB2253062A publication Critical patent/GB2253062A/en
Withdrawn legal-status Critical Current

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/16Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance
    • G01D5/165Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance by relative movement of a point of contact or actuation and a resistive track
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20Other details, e.g. assembly with regulating devices
    • F15B15/28Means for indicating the position, e.g. end of stroke
    • F15B15/2815Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
    • F15B15/2853Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using potentiometers

Abstract

Potentiometer apparatus, for detecting the position of a piston (10) and piston rod (8) in a pressure medium-actuatable working cylinder (7, 12), comprises a resistor assembly (4) and a sliding contact assembly (3, 6) guided thereon. Each of the two assemblies is in working connection with one of the two relatively displaceable elements. A holder (2) is received in a recess (5) in the cylinder wall and carries conductive and resistive tracks (21, 22) which are bridged by the springs (6) on the slider (3). The latter is coupled to the piston (10) by a divided spring (9) and thus moves over a much shorter travel than the piston, allowing the use of a very short resistive track carried by the holder so as to be insertable in the recess (5) without any dismantling of the piston-cylinder assembly. The tracks are connected to terminals (23-25) on the holder (2). <IMAGE>

Description

27 5 -e J.52 1 Potentiometer ADnaratus This invention relates to
potentiometer apparatus, and particularly to such apparatus for detecting the position of a piston in a pressure medium-actuatable working cylinder. Typically, such apparatus comprises a resistor arrangement and a sliding contact arrangement guided thereon.
Potentiometer apparatus is frequently used to detect relative movements or positions between movable and stationary elements. As a rule, a resistance path is provided along the direction of displacement, on which resistance path a slide is driven in accordance with the movement of the movable element. The position of the movable element relative to the stationary element is then established after calibration from the voltage picked up at the slide.
If apparatus of the above type is applied to a pressure medium-actuatable working cylinder, the resistance path and the slide are generally attached inside the piston rod. Such a potentiometer apparatus is known from German Patent Specification No. OS 33 25 399. In this arrangement the piston of the working cylinder is specially constructed so that it can accommodate only a specific U-shaped potentiometer apparatus inside it. The resistance path is then confined to the operating distance of the piston. The electrical connections are wired inside the piston chamber via a connection cable and guided outwards through a sealed cylinder bore. This potentiometer apparatus is provided for and can be used with only this specially constructed cylinder because of its specific construction. Such apparatus thus have the disadvantage that they cannot be used in other devices or device parts without considerable alteration.
The present invention is directed at potentiometer 4 2 apparatus of the above type, but which be used in various devices or equipment without the basic devices or equipment requiring substantial modification. In pursuing this end, the invention seeks also to retain a simple and economical construction of the apparatus.
According to the invention, potentiometer apparatus for monitoring the position of a first element movable relative to a second stationary element comprises a resistor assembly and sliding contact assembly movable thereon; a holder for mounting in the second element with a portion thereof adjacent the path of movement of the first element, which portion carries one of said assemblies; and an actuating membdr for mounting on the first element proximate said portion of the holder, which member is coupled to the other of said assemblies such that movement of the actuating member effects relative sliding movement of the assemblies. Normally, the actuating member is located on the first element by means of a reset spring, whereby movements of the member are proportionally reduced relative to the movements of the first element. In the preferred embodiment, the first element is a piston and the second element is a cylinder in a piston-cylinder mechanism with the holder extending through the wall of the cylinder.
The invention has the advantage that all or at least the essential functional components can be arranged on a one-piece holder. All that is needed for the holder part is a bore in the stationary element, in which the holder is inserted, while the actuating member can be easily connected to the movable element or be coupled thereto. The arrangement of a holder attached externally is also advantageous for repair work. If there is a defect, the holder can be exchanged for another.
There is particular advantage in the use of 3 potentiometer apparatus according to the invention for working cylinders with a small stroke. Generally, there is not enough room available for an internal potentiometer apparatus in such cylinders. With the potentiometer apparatus proposed according to the invention, substantially all the connection and fastening means are positioned externally by means of the holder. The holder may of course be constructed in such a way that connecting pins pass through the holder and make direct contact with the relevant assembly parts. Wiring of the holder is thereby made unnecessary.
Use of the apparatus of the invention in working cylinders with reset springs can be substantially independent of the piston stroke, since the reset spring is provided with an actuating ring and has a strokereducing action. For relatively large displacement distances the end of the holder can be of elongate construction and a correspondingly longer resistance and return path can be provided, which then require no stroke-reducing parts and achieve greater accuracy. For this purpose an elongate hole may be provided in the element bearing the holder.
The apparatus of the invention is, moreover, advantageously suitable for virtually all devices in which two parts are displaced relative to each other and in which the displacement distance is to be ascertained as the position of one device part with respect to the other. Since such a series potentiometer apparatus can be economically produced and attached merely by a bore, it is especially suitable for retrofitting on many devices in use which are subsequently to be controlled by computers or other apparatus.
Three embodiments of the invention will now be described by way of example and with reference to the accompanying drawings wherein:
1 4 Figure I shows a pneumatic cylinder with potentiometer apparatus, in which the resistor arrangement is attached to the holder, Figure 2 shows the holder in detail, Figure 3 shows the pneumatic cylinder with slider arrangement on the holder, Figure 4 shows details of the holder and the slider and resistor arrangements according to Fig. 3, and Figure 5 shows a pneumatic cylinder with potentiometer apparatus; resistor and slider arrangements are attached to the holder.
Figure 1 shows a potentiometer apparatus in a pneumatically controlled working cylinder, in which the resistor arrangement is attached to the holder and the slider arrangement to an actuating ring. The working cylinder contains the two device parts displaceable with respect to one another. One of these device Darts consists of a stationary cylinder wall 7, while the movable device part comprises an actuating ring 3 between a split reset spring 9.
The potentiometer apparatus is arranged with its holder 2 in a recess in the cylinder wall 7 of the working cylinder 12. The holder comprises a plastics materia'.11. The holder 2 projects into the inner chamber of the working cylinder, in which a piston 10 connected 1 to a piston rod 8 is guided axially displaceably. The U piston rod 8 projects at one end sealedly out of the working cylinder and serves to receive possible work loads. A spiral reset spring 9 is arranged on the piston rod, which reset spring 9 is split in the area of the recess. The recess is constructed as a bore 5. At the point of the bore 5 there is located an actuating ring 3 between the two spring parts, the two spring ends resting on said actuating ring 3. When the piston 10 is actuated, therefore, the actuating ring 3 is moved by the spring 9 in the axial direction. The actuating ring 3 is of a width which is greater than the diameter of the bore 5. A slider 6 is attached to this actuating ring 3, which slider 6 projects into the bore 5. A tapped bore 14 is installed in the cylinder wall opposite the bore 5, in which bore 14 there is located guide pin 15, which engages in a longitudinal slot in the actuating ring. The guide pin 15 prevents the actuating ring 3 from being displaced radially by the movement processes of the reset spring 9. In the rest state, the piston 10 is located against a side wall stop 16, which lies opposite the outlet opening of the piston rod 8. This side has a closing member 17, which contains a pressure medium connection 13, which opens on the closure side into a pressure medium chamber 11. The piston 10 is guided sealedly with respect to the outer cylinder wall 7 and is moved in the axial direction towards the outlet opening of the piston rod when the pressure medium chamber 11 is subjected to pressurization.
The holder 2 is located in the bore 5. The former may be firmly connected to the outer cylinder wall by means of a screw connection. This results in a firm a - 1 6 - axial orientation of the holder 2. This screw connection may be made pressure-tight with the aid of sealing. materials. The end of the holder projects into the bore with a projection 5a, whose diameter corresponds to the diameter of the bare 5. A resistor arrangement 4 is located on the projection 5a, which resistor arrangement 4 is connected with three contact pins (not shown in Figure 1) on the opposite holder side. By means of the contact pins, the resistor arrangement 4 can be electrically connected to an external apparatus via a plug contact box 1.
The slider 6 is arranged in the inner cylinder chamber on the side opposite the holder 2, the sliding contact springs of said slider 6 resting spring-loadedly on the resistor arrangement 4. The slider connected with the actuating ring 3 forms the slider arrangement 6. The construction of-the holder 2 is shown in more detail in the two different views of Figure 2 of the drawings. The holder has a square upper part 28 and a cylindrical bottom part 26. The upper part 28 consists of a plastics material, into which three metal pins are cast as integral wiring. The three contact pins 23, 24, 25 project out of the upper part 28 and form the connecting means. Two fastening bores 20, 27 are formed at two diagonally opposite corner points, which bores 20, 27 serve to receive the fastening screws. The resistor arrangement 4 is attached to the cylindrical bottom part 26, which is constructed as a cylindrical shank. The resistor arrangement 4 consists of a resistance path 22 and a return path 21. The resistance path 22 is connected to two contact pins 23, 25 at its corner points, said contact pins 23, 25 passing through the. holder 2 and projecting on the opposite side as flat 1 contact pins 23, 25. The bottom part 26 has a shank length corresponding approximately to the wall thickness of the cylinder tube. The shank length may be greater, however, whereby it is then possible to adapt the holder 2 to different mounting parts by using washers. The bottom part 26 is defined by a flat end 29.
The return path 21 is the same size as the resistance path 22 and is arranged in parallel. therewith. The return path 21 consists of a material of good electrical conductivity, such as, for example, copper with a thin resistance layer applied thereto, and is connected in the middle with a contact pin 24, which also projects on the other holder side as a flat contact pin 24. This thin resistance layer is short- circuited by the copper underneath and thus displays good conductivity. The only task which coating of the copper path with resistance material has is that of providing a constant contact resistance between slider and return path, so that the voltages present at the voltage divider always permit reproducible position detection. The embodiment of the potentiometer apparatus shown in Figures 1 and 2 consists substantially of two functional elements. One of the functional elements is formed by the resistor arrangement on the holder, while the other functional element comprises the slider arrangement. The potentiometer apparatus only becomes a functioning unit by the installation of its two functional elements. The functional element of the slider 7 is fastened to the actuating ring 3 in such a way that the sliding contact spring rests on the resistor arrangement 4 of the holder and can be moved slidingly on the resistor arrangement through movement of the piston 10. The sliding contact spring makes contact widthwise with both the resistance path 22 and the return path 21, such that an electrical connection arises between the two paths. The sliding contact spring is constructed with a split in the area of its sliding surface, such that it only rests slidingly an the paths of the resistor arrangement.
If the potentiometer apparatus is connected to an external apparatus (not shown) by the plug contact box 1, in the switched-on state a certain electrical voltage is present at the two contact pins 23, 25, which are connected to the resistance path 22. Through the position of the slider 6, the whole voltage or part of this voltage is also present at the return path 21. The level of this part voltage corresponds to the position of the slider 6 on the resistance path 22 and thus also to the position of the actuating ring 3 in the working cylinder 12. Since the position of the actuating ring 3 is in turn dependent on the position of the piston in the working cylinder, the tapped voltage is in a particular relationship to the position of the piston. The actuating ring 3 is not actuated directly by the piston, however, but rather is only entrained by the movement of the reset spring. Since the movement distance of the spring corresponding to the number of its windings is smaller than the distance of piston movement, a specific displacement reducing ratio may be determined by the number of windings. It is thereby possible to detect the piston position of a relatively long working cylinder with a relatively small potentiometer holder. In accordance with the piston position, the respective part voltage, which corresponds to the position of the piston, can then be picked off at the contact pin 24 of the return path 21.
9 - With an alteration in the position of the piston 10, there thus arises a corresponding alteration in the voltage at the contact pin 24 of the return path 21, such that detection of the respective piston position is possible at any time. Moreover, values can be also be detected by the potentiometer apparatus which depend on the piston position, such as, for example, the pressure in a pressure medium chamber or other comparable values. Figure 3 of the drawings shows an exemplary embpdiment, in which the slider arrangement 32 is attached to the holder 30 and the resistor arrangement 31 to the actuating ring 33 of the working cylinder 35. The working cylinder 35 has the same construction as the above-described exemplary -embodiment, which is shown in Figure 1 of the drawings. Even the holder 30 is substantially identical to the construction described under Figure 1 of the drawings, such that with this exemplary embodiment only the elements of differing construction are mentioned. These relate merely to the slider arrangement 32 and the resistor arrangement 31. In this exemplary embodiment, the slider arrangement is located on the holder 32, while the resistor arrangement is attached to the actuating ring 33. The slider arrangement 32 consists of three sliding contact springs, which are attached to the holder 30 and connected to the contact pins. Opposite the slider arrangement 32 there is located the resistor arrangement 31. The individual sliding contact springs rest springloadedly on the resistor arrangement 31. The details of the resistor arrangement 31 and the slider arrangement 32 are shown in more detail in Figure 4 of the drawings.
Figure 4 of the drawings shows the substantial part of the holder with the associated slider arrangement and part of the actuating ring with the associated resistor arrangement. The slider arrangement consists of three isolatedly attached sliding contact springs 43, 49, 52, which are arranged behind one another in the direction of displacement. The individual sliding contact springs 43, 49, 52 form a unit with the contact pins 40, 41, 53 and are cast in the holder 42. The resistor arrangement is attached on the actuating ring 46 opposite the slider arrangement. The actuating ring 46 serves as a- carrier layer for the resistor arrangement. A rectangular surface is provided on the carrier layer for application of the resistance and conducting layer. This surface consists of thre e partial surfaces 47, 48, 50 of the same size lying behind each other in the direction of displacement, a copper layer 45, 51 and a resistance layer 44 being applied to some of said partial surfaces 47, 48, 50.
The carrier layer consists of an insulating plastics material, from which the usual actuating ring 46 is also produced. However, the actuating ring may also be made of a metal material, onto which an additional insulation layer would have to be applied. It would also be feasible for the resistor arrangement to be connected to -the actuating ring 33 by a releasable connection or to be attached directly to the reset spring. With relatively small stroke distances the resistor arrangement or the slider arrangement could be fastened directly to the piston rod according to the exemplary embodiment of Figure 1.
The resistor arrangement consists of a rectangular rpsistance path, whose longitudinal extension runs in the direction of displacement of the piston rod. This resistance path 44 may be imagined as three equal-sized partial surfaces lying behind each other in the direction of displacement, the two outer partial surfaces 47, 50 being provided with a copper base 45, 51. All three partial surfaces are coated entirely with a resistance material. Each of the partial surfaces 47, 48, 50 acts as a sliding surface for one of the three sliding contact springs 43, 49, 52. In the assembled state, the resistor arrangement and the slider arrangement are arranged in such a way that the sliding contact springs 43, 49, 52 each rest on one of the partial surfaces 47, 48, 50 under slight pressure. They can be displaced over the whole partial surface in the direction of displacement upon displacement of the piston rod or the actuating ring 46.
If the potentiometer apparatus is electrically connected to an_external apparatus (not shown here) with the aid of the plug contact box, a voltage is present at the two outer sliding contact springs 43, 52. This is transmitted via the contact springs 43, 52 to the respective copper base 45, 51. The resistance value of the resistance layer 44 lying thereover can be ignored, because it only increases the contact resistance slightly. The resistance layer 44 with the copper base serves merely to produce as even as possible a sliding characteristic for the sliding contact springs 43, 49, 52 and thus to keep wear slight. Through the connection of the two copper bases with the pure resistance path lying therebetween, the entire voltage is present at this intermediate partial surface. The sliding contact spring 49 picks off a specific voltage value, which corresponds to the respective displacement distance of the actuating ring with respect to its starting position. Since the actuating ring is arranged between the reset spring parts, a reducing ratio also arises again between the displacement distance of the piston 34 and the displacement distance of the actuating ring 33. Since this ratio is linear, the tapped voltage represents a corresponding value of the respective position of the piston. Since the holder arrangement has only a small circular surface at its end, only small actuating distances can be picked off at the retistance path. This could possibly lead to inaccuracies of measurement, which may be compensated, however, by a special embodiment. In such cases, embodiments are feasible in which the holder is of elongate construction, whereby the sliding distance can be considerably extended. In these cases it is possible for the sliding surface to be of a length corresponding to the distance of movement of the piston or the piston rod.
Figure 5 of the drawings shows an exemplary embodiment of the potentiometer apparatus, in which both - 62 and the slider arrangement the resistor arrangement 79 are attached to the holder 61 and in which the slider arrangement 79 is in working connection with the actuating ring 67 of the working cylinder 78.
The working cylinder 78 is constructed like the pneumatic cylinder described under the other two exemplary embodiments according to Figures 1 and 2 of the drawings. The working cylinder 78 consists of a cylinder housing 75, a piston 73, a pressure medium connection 77, a reset spring 74 and a piston rod 73. If nothing else is mentioned here,-the Darts of the working cylinder 78 are constructed as in the exemplary embodiments described before and function in the same way..
The holder 61 is located in a bore 69 in the cylinder housing 75. The functional elements of the potentiometer apparatus, i.e. both the slider arrangement and the resistor arrangement, are attached to the end of the holder 61 facing the bore. Three plug contact pins (not shown here) are provided on the opposite holder side, which pins can be connected to the plug contact box 60. The functional elements of the potentiometer apparatus on t he holder 61 consist of the resistor arrangement 62 attached to the end and the slider arrangement 79 guided slidingly thereon. The holder 61 and the resistor arrangement 62 are constructed substantially like the holder 2 and the resistor arrangement 4 of the exemplary embodiment of Figure I of the-drawings. Moreover, a guide rail 66 is additionally located on the e nd of the holder 61, in which rail 66 the slider arrangement 79 is displaceably arranged. The guide rail is constructed as a U-rail, in whose central connection surface a guide slit is left open, through which a driving member projects in the direction of the piston rod 73. This guide rail 66 runs longitudinally of the direction of displacement of the piston rod. To define the displacement path of the slider arrangement 79, the guide rail 66 is closed at its ends. The slider arrangement 79 consists of a displaceable carrier part 68, which is arranged axially movably in the guide rail 66 and to which is fastened the sliding contact spring 72. To drive the carrier part 68 there is provided a pin 70 arranged in the direction of the piston rod, which pin. 70 is fastened to the carrier part 68 and forms a driving member. The driving member 70 engages in a bore located in the actuating ring 67, which bore moves the slider arrangement 79 upon actuation of the piston of the working cylinder. The guide rail 66 is closed at each of its two ends by an end plate 63. A guide pin 65 is mounted in the axial direction in the end plate 63, which is located in the direction of displacement, said guide pin 65 projecting into an axial bore 71 of the carrier part 68 and serving to guide the slider arrangement.
A spiral compression spring is arranged coaxially to the guide pin 65, against the reset force of which compression spring 64 the slider arrangement 79 can be displaced. On the side of the slider arrangement 79 facing the resistor arrangement 62 there is fastened a sliding contact spring 72, which, under slight spring pressure, rests against both the resistance and the return paths. The sliding contact spring 72, as already described under the exemplary embodiment according to Figure 1 of the drawings, is constructed with a split and lies with one part on the resistance path and the other part on the return path.
If the piston 76 of the working cylinder 78,is moved, the slider arrangement 79 is also displaced in the direction of movement of the piston through the working connection of the driving member 70 with the actuating ring. The sliding contact spring 72 is also moved simultaneously on the resistance path, such that a voltage corresponding to the respective position of the piston can be picked off at the potentiometer apparatus. The function of the potentiometer apparatus is the same as that already described under the exemplary embodiment of Figure 1 of the drawings. In this exemplary 1 embodiment too, a distance-reducing displacement is achieved through the reset,spring. However, the holder 61 could also likewise be constructed in the form of an elongate hole, in order to achieve a longer displacement distance for the slider arrangement 79.
The exemplary embodiments described above of the potentiometer apparatus according to the invention are, however, not restricted to the abovedescribed ' possibilities of application in working cylinders alone, but rather can also be used universally in other device parts. A prerequisite therefor is, however, that two device parts are present which are displaceable in axial relation to each other. It does not matter whether the potentiometer apparatus is used in pressure mediumactuated systems or other movable apparatuses. In pressure medium-actuated devices, however, it may be necessary to pro.vide the holder with a seal to make it pressure-tight. It is also feasible for the holder to be provided with a pressure medium connection, to mount It in a pressure medium chamber. It is also feasible to connect the pressure medium connection to the holder in a plug-in manner and supply a pressure medium line to the pressure medium chambers through the holder..
claims 1. Potentiometer apparatus for monitoring the position of a first element movable relative to a second stationary element, comprising a resistor assembly and sliding contact assembly movable thereon; a holder for mounting in the second element with a portion thereof adjacent the path ofmovement of the first element, which portion carries one of said assemblies; and an actuating member for mounting on the first element proximate said portion of the holder, which member is coupled to the other of said assemblies such that movement of the actuating member effects relative sliding movement of the assemblies.

Claims (1)

  1. 2. Apparatus according to Claim 1 wherein the holder is mounted in a
    recess in a wall portion of the second element.
    3. Apparatus according to Claim I or Claim 2 wherein the actuating member is located on the first element by means of a reset spring, whereby movements of the member are proportionally reduced relative to the movements of the first element.
    4. Apparatus according to any preceding Claim wherein the first element is a piston and the second element is a cylinder in a piston-cylinder mechanism with the holder extending through the wall of the cylinder.
    S. Apparatus according to any preceding Claim wherein said one assembly is the resistor assembly.
    6. Apparatus according to any preceding Claim wherein both assemblies are mounted in the holder.
    7. Apparatus according to Claim 6 wherein said other assembly is displaceably mounted in the holder, and coupled to the actuating member by a drive connector.
    8. Apparatus according to Claim 7 wherein a guide rail is located at the end of the holder, in which rail there is mounted a displaceable carrier movable against a M_ reset spring, the carrier part being coupled to the drive connector.
    9. Apparatus according to any of Claim 1 to 5 wherein the other assembly is carried on the actuating member.
    10. Apparatus according to any preceding Claim wherein the holder includes integral wiring connecting the resistor and contact assemblies to electrical terminals.
    11. Apparatus according to any preceding Claim wherein said holder portion is constructed as a cylindrical shank which serves for guidance in its mounting in the second element.
    12. A potentiometer apparatus according to any preceding Claim wherein the resistor assembly comprises a rectangular resistance path and a return path running parallel thereto, and is connected with three contact pins on the side of the holder opposite the assembly for coupling to a plug-in contact box.
    13. Apparatus according to any of Claim I to 11 wherein the sliding contact assembly comprises three mutually isolated sliding contact springs connected with three contact pins for coupling to a plug contact box.
    14. Apparatus according to Claim 13 wherein the resistor assembly comprises a rectangular resistance having three successive partial surfaces in the displacement direction, each constituting a third of the total surface and serving as a sliding surface for one of the sliding contact springs, the two end surfaces having a copper base.
    15. Potentiometer apparatus substantially as described herein with reference to Figure 1 and 2; Figures 3 and 4; or Figure 5 of the accompanying drawings.
    16. A piston-cylinder mechanism with apparatus according to any preceding Claim incorporated therein.
    17. A mechanism according to Claim 16 wherein the holder includes a conduit for the passage of fluid under pressure for operating the mechanism.
GB9203759A 1991-02-21 1992-02-21 Potentiometer apparatus for measuring the displacement of a piston in a cylinder Withdrawn GB2253062A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19914105703 DE4105703C2 (en) 1991-02-21 1991-02-21

Publications (2)

Publication Number Publication Date
GB9203759D0 GB9203759D0 (en) 1992-04-08
GB2253062A true GB2253062A (en) 1992-08-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9203759A Withdrawn GB2253062A (en) 1991-02-21 1992-02-21 Potentiometer apparatus for measuring the displacement of a piston in a cylinder

Country Status (4)

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DE (1) DE4105703C2 (en)
FR (1) FR2673319A1 (en)
GB (1) GB2253062A (en)
IT (1) IT1254623B (en)

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FR2717260A1 (en) * 1994-03-08 1995-09-15 Volkswagen Ag Device for determining the position of an adjustment element.

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DE19634308A1 (en) * 1996-08-24 1998-02-26 Roemheld A Gmbh & Co Kg Position measuring system for linear units
FR2794236B1 (en) * 1999-05-26 2006-06-16 Serta Device for knowing the position and for measuring the movement of the piston or piston rod in the chamber of a cylinder of the type comprising a linear rectiline linear potentiometry sensor
DE10219959B4 (en) * 2002-05-03 2006-05-24 Schleifring Und Apparatebau Gmbh Slip ring or sliding track for the transmission of electrical signals between two mutually movable units
FR3086720B1 (en) * 2018-10-02 2021-01-15 Electricite De France FLUIDIC CONNECTION DEVICE AND ASSOCIATED SYSTEM

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GB2207508A (en) * 1987-08-01 1989-02-01 Crystalate Electronics Potentiometer
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FR2717260A1 (en) * 1994-03-08 1995-09-15 Volkswagen Ag Device for determining the position of an adjustment element.
GB2288240A (en) * 1994-03-08 1995-10-11 Volkswagen Ag Device for detecting the position of a control element
GB2288240B (en) * 1994-03-08 1998-09-30 Volkswagen Ag Device for detecting the position of a control element

Also Published As

Publication number Publication date
ITMI920385D0 (en) 1992-02-21
DE4105703C2 (en) 1993-03-25
DE4105703A1 (en) 1992-08-27
ITMI920385A1 (en) 1993-08-21
GB9203759D0 (en) 1992-04-08
FR2673319A1 (en) 1992-08-28
IT1254623B (en) 1995-09-28

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