WO1989007236A1 - Position sensor - Google Patents

Position sensor Download PDF

Info

Publication number
WO1989007236A1
WO1989007236A1 PCT/DK1989/000008 DK8900008W WO8907236A1 WO 1989007236 A1 WO1989007236 A1 WO 1989007236A1 DK 8900008 W DK8900008 W DK 8900008W WO 8907236 A1 WO8907236 A1 WO 8907236A1
Authority
WO
WIPO (PCT)
Prior art keywords
profiles
position sensor
resistor element
slider
slide block
Prior art date
Application number
PCT/DK1989/000008
Other languages
French (fr)
Inventor
Henning Aage Westergaard Petersen
Original Assignee
A/S Doublet-Record
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
Application filed by A/S Doublet-Record filed Critical A/S Doublet-Record
Publication of WO1989007236A1 publication Critical patent/WO1989007236A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING 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
    • G01D5/00—Mechanical 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
    • G01D5/12—Mechanical 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
    • G01D5/14—Mechanical 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
    • G01D5/16—Mechanical 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
    • G01D5/165—Mechanical 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness

Definitions

  • the present invention relates to a position sensor comprising a hous ⁇ ing, a resistor element and a slider which is provided with a slide block connecting the conductor paths of the resistor element.
  • Known position sensors comprise a resistor element in the form of a linear potentiometer which is built into complex profiles or milled tubes. A slider is placed into one of these profiles or tubes, said slider being provided with a slide block connecting the conductor paths of the potentiometer. High requirements are made to the precision of the milling in these constructions in order to obtain a correct posi ⁇ tion measurement, and thereby the position sensors become expensive.
  • a position sensor of the above-mentioned type which is characterized in comprising two substantially U-shaped profiles the one placed inside the other and orientated in opposite directions, said profiles being interconnec ⁇ ted by a ball guide the balls of which are arranged in tracks provided in each of the two side flanges of the U-profiles; in the resistor element comprising a linear potentiometer fixed to one of the U-profi- les by elastic glue means; and in the other U-profile comprising the slider provided with the slide block.
  • This position sensor may in principle be manufactured using a modified ball guide for a drawer.
  • the U-profiles are easily punched out and bent.
  • the two U-profiles and the ball guide ensures a high degree of transversal stability in any direction and hence a close accuracy in determining the position.
  • the position sensor according to the invention is not limited for use in connection with apparatus for working the soil as mentioned above. It may be used for other purposes and, generally, it may be used in pneumatic and hydraulic systems for correct determination of the posi ⁇ tion of a piston. A position sensor according to the invention will render such construction commercially realistic.
  • FIG. 1 is a view illustrating a position sensor according to the invention mounted between to end sockets and within a bel ⁇ low
  • Fig. 2 a perspective view illustrating the two U-profiles of the position sensor
  • Fig. 3 a view illustrating the construction of the position sensor
  • Fig. 4 a cross-section of the position sensor.
  • Fig. 1 shows a position sensor 1 comprising two end sockets 2 each provided with a connection flap 3 for connection with the elements the mutual position of which is to be measured.
  • the end sockets 2 are in ⁇ terconnected by a bellow 4 which is fixed to the end sockets by any well known means as for example by gluing or clamp clips to protect the position sensor against dust or the like.
  • a bellow 4 which is fixed to the end sockets by any well known means as for example by gluing or clamp clips to protect the position sensor against dust or the like.
  • two substantially U-formed profiles 5 and 6 are placed.
  • the U-shapes of the two U-pro ⁇ files are orientated in opposite directions and one of the U-profiles 5 is slightly smaller than the other U-profile 6 and the first is pla- ced inside the latter.
  • the two U-profiles are interconnected by means of a ball guide 7 with balls 8 placed in ball tracks 9,10 in each side flange of the U-profiles.
  • the resistor element of the position sensor comprises a linear potentiometer 11 which is fixed onto the greater U-profile 6 and which is connected with a glide block 12 fixed to the smaller U-profile 5 through an insulation block 13.
  • the glide block connects two tracks of the potentiometer and an output signal is ob ⁇ tained which indicates the position of the glide block and hence the length of the position sensor as measured between the connection flaps 3.
  • Fig. 3 shows the construction principle of the position sensor.
  • the potentiometer is arranged so as to provide all wires 14 at the one end in order to facilitate mounting.
  • the potentiometer is fixed to the U-profile 6 by elastic glue means 15 which preferably consists of doub- le adhesive tape.
  • elastic glue means 15 which preferably consists of doub- le adhesive tape.
  • the position sensor is substantially insensitive to any transversal actions as the construction becomes very resistant to bending, seeing that a U-profile is used both for supporting the potentiometer 11 and as the slider for supporting the slide block.
  • the position sensor may be used in an apparatus for working the soil having a two-piece frame construction comprising on the one hand a supporting frame and on the other hand a tool provided frame.
  • the working depth is determined by measurement of the mutual distance between the two frames.
  • a central control unit which may be placed on the apparatus for working the soil. From the control unit the signal is transmitted to an operation unit placed in the trac ⁇ tor cab and a direct indication of the registered working depth is shown on a display.
  • the positioning of the tool provided frame may be adjusted in accordance with this indication by means of the central electro-hydraulic control unit as the operator activates the signal transmitting operation unit.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

A position sensor comprising a housing, a resistor element and a slider which is provided with a slide block (12) connecting the tracks of the resistor element said position sensor being very simple to manufacture and yet reliable as it comprises two U-profiles (5, 6) arranged inside each other making it very resistant to bending. Said U-profiles (5, 6) are interconnected by a ball guide (7) wherein the balls (8) run in tracks (9, 10) in each of the side flanges of the U-profiles thus rendering it very resistant to bending. The resistor element comprises a linear potentiometer (11) which is fixed to one of the U-profiles (6) by elastic glue means (15) and the other U-profile constitutes the slider which is provided with a slide block (12).

Description

POSITION SENSOR Background of the Invention.
The present invention relates to a position sensor comprising a hous¬ ing, a resistor element and a slider which is provided with a slide block connecting the conductor paths of the resistor element.
Several sensors of this type are known. However, known position sen¬ sors which are suitable for registration of a comparatively precise determination of a position, e.g. with a precision of approximately 1/10 mm or less, are so expensive that most apparatus comprising such sensors become uneconomical. This is the case e.g. in harrow construc¬ tions where it is desired to determine the working depth by measuring the mutual position of two support frames.
Known position sensors comprise a resistor element in the form of a linear potentiometer which is built into complex profiles or milled tubes. A slider is placed into one of these profiles or tubes, said slider being provided with a slide block connecting the conductor paths of the potentiometer. High requirements are made to the precision of the milling in these constructions in order to obtain a correct posi¬ tion measurement, and thereby the position sensors become expensive.
Accordingly, a need exists for a simple, reliable and solid position sensor which is inexpensive to manufacture and which may be used for a comparatively precise measuring even under difficult working condi¬ tions as for example in an apparatus for working the soil.
Therefore, it is the object of the present invention to remedy the above-mentioned drawbacks connected with the known position sensors and to provide a position sensor which is simple to manufacture and which is moreover reliable even under difficult working conditions.
According to the invention this object is achieved with a position sensor of the above-mentioned type which is characterized in compris- ing two substantially U-shaped profiles the one placed inside the other and orientated in opposite directions, said profiles being interconnec¬ ted by a ball guide the balls of which are arranged in tracks provided in each of the two side flanges of the U-profiles; in the resistor element comprising a linear potentiometer fixed to one of the U-profi- les by elastic glue means; and in the other U-profile comprising the slider provided with the slide block.
Hereby, an especially simple and reliable position sensor is obtained. This position sensor may in principle be manufactured using a modified ball guide for a drawer. The U-profiles are easily punched out and bent. Moreover, the two U-profiles and the ball guide ensures a high degree of transversal stability in any direction and hence a close accuracy in determining the position.
Moreover, it is possible to eliminate the uncertainty which arises due to variations in temperature as longitudinal variations of the U-pro¬ files are absorbed by the elastic glue means. Furthermore, using of one of the U-profiles as the slider ensures that a very stiff and thus a very precise construction is obtained. Additionally, it is possible to obtain longer sensors in a simple way as more sensors may easily be connected end to end for measuring of variations in positions requiring strokes greater than one sensor may manage.
The position sensor according to the invention is not limited for use in connection with apparatus for working the soil as mentioned above. It may be used for other purposes and, generally, it may be used in pneumatic and hydraulic systems for correct determination of the posi¬ tion of a piston. A position sensor according to the invention will render such construction commercially realistic.
Description of the Drawings.
In the following the invention is described more in detail with refe¬ rence to the accompanying drawing, wherein Fig. 1 is a view illustrating a position sensor according to the invention mounted between to end sockets and within a bel¬ low, Fig. 2 a perspective view illustrating the two U-profiles of the position sensor, Fig. 3 a view illustrating the construction of the position sensor, and Fig. 4 a cross-section of the position sensor.
Fig. 1 shows a position sensor 1 comprising two end sockets 2 each provided with a connection flap 3 for connection with the elements the mutual position of which is to be measured. The end sockets 2 are in¬ terconnected by a bellow 4 which is fixed to the end sockets by any well known means as for example by gluing or clamp clips to protect the position sensor against dust or the like. Between the two end soc¬ kets two substantially U-formed profiles 5 and 6 are placed. As it appears more clearly from Figs. 2 and 4 the U-shapes of the two U-pro¬ files are orientated in opposite directions and one of the U-profiles 5 is slightly smaller than the other U-profile 6 and the first is pla- ced inside the latter. The two U-profiles are interconnected by means of a ball guide 7 with balls 8 placed in ball tracks 9,10 in each side flange of the U-profiles. The resistor element of the position sensor comprises a linear potentiometer 11 which is fixed onto the greater U-profile 6 and which is connected with a glide block 12 fixed to the smaller U-profile 5 through an insulation block 13. The glide block connects two tracks of the potentiometer and an output signal is ob¬ tained which indicates the position of the glide block and hence the length of the position sensor as measured between the connection flaps 3.
Fig. 3 shows the construction principle of the position sensor. The potentiometer is arranged so as to provide all wires 14 at the one end in order to facilitate mounting. The potentiometer is fixed to the U-profile 6 by elastic glue means 15 which preferably consists of doub- le adhesive tape. Hereby, the potentiometer becomes insensitive to longitudinal variations due to variating temperatures and accordingly a precise measuring is obtained. The position sensor is substantially insensitive to any transversal actions as the construction becomes very resistant to bending, seeing that a U-profile is used both for supporting the potentiometer 11 and as the slider for supporting the slide block. In order to eliminate clearances and to improve construc¬ tion stiffness the two side flanges have been bent less than 90° and more than 90°, respectively prior to assembly thus urging the side flanges elastically into mutual contact through the interposed balls 8 after assembling
The position sensor may be used in an apparatus for working the soil having a two-piece frame construction comprising on the one hand a supporting frame and on the other hand a tool provided frame. In this apparatus the working depth is determined by measurement of the mutual distance between the two frames. Through the wires 14 the output signal of the position sensor is conducted to a central control unit which may be placed on the apparatus for working the soil. From the control unit the signal is transmitted to an operation unit placed in the trac¬ tor cab and a direct indication of the registered working depth is shown on a display. The positioning of the tool provided frame may be adjusted in accordance with this indication by means of the central electro-hydraulic control unit as the operator activates the signal transmitting operation unit.

Claims

C l a i m s.
1. A Position sensor comprising a housing, a resistor element and a slider which is provided with a slide block connecting the conductor paths of the resistor element, c h a r a c t e r i z e d in comprising two substantially U-shaped profiles the one placed inside the other and orientated in opposite directions, said profiles being interconnec¬ ted by a ball guide the balls of which are arranged in tracks provided in each of the two side flanges of the U-profiles; in the resistor element comprising a linear potentiometer fixed to one of the U-profi¬ les by elastic glue means; and in the other U-profile comprising the slider provided with the slide block.
2. A Position sensor according to claim 1, c h a r a c t e r i z e d in that the side flanges of both U-profiles are bent less than 90° and more than 90°, respectively, before assembly, so that the side flanges are elastically urged into mutual contact through the interposed balls after assembling.
3. A Position sensor according to claims 1 or 2, c h a r a c t e r i ¬ z e d in that the elastic glue means comprises a double gluing tape.
4. A Position sensor according to claims 1, 2 or 3, c h a r a c t e ¬ i z e d in that the housing comprises two end sockets, each of which is connected with one of the U-profiles and a bellow member surrounding the U-profiles and fixedly connected with both end sockets.
PCT/DK1989/000008 1988-01-27 1989-01-24 Position sensor WO1989007236A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK383/88 1988-01-27
DK38388A DK38388A (en) 1988-01-27 1988-01-27 EARTHWORKING EQUIPMENT AND POSITION SENSOR FOR USE HERE

Publications (1)

Publication Number Publication Date
WO1989007236A1 true WO1989007236A1 (en) 1989-08-10

Family

ID=8092879

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK1989/000008 WO1989007236A1 (en) 1988-01-27 1989-01-24 Position sensor

Country Status (3)

Country Link
AU (1) AU3216089A (en)
DK (1) DK38388A (en)
WO (1) WO1989007236A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1934551A1 (en) * 2005-10-13 2008-06-25 Commonwealth Scientific and Industrial Research Organisation System and garment for detecting movement
WO2015172072A1 (en) * 2014-05-08 2015-11-12 Baker Hughes Incorporated Metal bellows equalizer capacity monitoring system
US9988887B2 (en) 2014-05-08 2018-06-05 Baker Hughes, A Ge Company, Llc Metal bellows equalizer capacity monitoring system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2436262A1 (en) * 1973-08-07 1975-02-20 Gallacher Length gauge for analysis of seismic recordings - gives accurate indication of lengths up to fifty cm
EP0219565A1 (en) * 1985-10-22 1987-04-29 Horst Siedle Kg Potentiometric measuring system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2436262A1 (en) * 1973-08-07 1975-02-20 Gallacher Length gauge for analysis of seismic recordings - gives accurate indication of lengths up to fifty cm
EP0219565A1 (en) * 1985-10-22 1987-04-29 Horst Siedle Kg Potentiometric measuring system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1934551A1 (en) * 2005-10-13 2008-06-25 Commonwealth Scientific and Industrial Research Organisation System and garment for detecting movement
EP1934551A4 (en) * 2005-10-13 2009-12-30 Commw Scient Ind Res Org System and garment for detecting movement
US8291779B2 (en) 2005-10-13 2012-10-23 Commonwealth Scientific And Industrial Research Organisation System and garment for detecting movement
WO2015172072A1 (en) * 2014-05-08 2015-11-12 Baker Hughes Incorporated Metal bellows equalizer capacity monitoring system
US9988887B2 (en) 2014-05-08 2018-06-05 Baker Hughes, A Ge Company, Llc Metal bellows equalizer capacity monitoring system

Also Published As

Publication number Publication date
DK38388A (en) 1989-06-06
DK38388D0 (en) 1988-01-27
AU3216089A (en) 1989-08-25

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