CA2035133A1 - Force or pressure measuring device - Google Patents
Force or pressure measuring deviceInfo
- Publication number
- CA2035133A1 CA2035133A1 CA002035133A CA2035133A CA2035133A1 CA 2035133 A1 CA2035133 A1 CA 2035133A1 CA 002035133 A CA002035133 A CA 002035133A CA 2035133 A CA2035133 A CA 2035133A CA 2035133 A1 CA2035133 A1 CA 2035133A1
- Authority
- CA
- Canada
- Prior art keywords
- piston
- pressure
- diaphragm
- force
- housing
- 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.)
- Abandoned
Links
- 239000013536 elastomeric material Substances 0.000 claims abstract description 38
- 229910010293 ceramic material Inorganic materials 0.000 claims description 8
- 238000011049 filling Methods 0.000 claims description 7
- 230000002093 peripheral effect Effects 0.000 claims description 7
- 238000005452 bending Methods 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 abstract description 6
- 230000002463 transducing effect Effects 0.000 abstract 1
- 238000013461 design Methods 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000005259 measurement Methods 0.000 description 7
- 238000012986 modification Methods 0.000 description 7
- 230000004048 modification Effects 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 238000009530 blood pressure measurement Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000007650 screen-printing Methods 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- 102000000591 Tight Junction Proteins Human genes 0.000 description 1
- 108010002321 Tight Junction Proteins Proteins 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 210000001578 tight junction Anatomy 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/14—Housings
- G01L19/148—Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/26—Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B31/00—Screwed connections specially modified in view of tensile load; Break-bolts
- F16B31/02—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load
- F16B31/028—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load with a load-indicating washer or washer assembly
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/14—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measurement of pressure
- G01F23/16—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid
- G01F23/164—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid using a diaphragm, bellow as transmitting element
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/14—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measurement of pressure
- G01F23/18—Indicating, recording or alarm devices actuated electrically
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/02—Measuring force or stress, in general by hydraulic or pneumatic means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/0061—Electrical connection means
- G01L19/0084—Electrical connection means to the outside of the housing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
- G01L19/0627—Protection against aggressive medium in general
- G01L19/0645—Protection against aggressive medium in general using isolation membranes, specially adapted for protection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/14—Housings
- G01L19/142—Multiple part housings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/14—Housings
- G01L19/147—Details about the mounting of the sensor to support or covering means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
- G01L5/243—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed using washers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0051—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance
- G01L9/0052—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements
- G01L9/0055—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements bonded on a diaphragm
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Mechanical Engineering (AREA)
- Measuring Fluid Pressure (AREA)
- Measurement Of Force In General (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
Abstract:
A force or pressure measuring device comprising a pot-like sensor body having a piston inserted thereto forming a narrow annular gap with opposing cylindrical surfaces of the interior of the sensor body and a space beneath the bottom end of said piston, the gap and the space being filled with elastomeric material strongly adhering to surfaces in contact therewith; a bottom wall of said sensor body being integrally formed as a diaphragm having pressure transducing elements applied thereto.
Such a force or pressure measuring device is used in devices provided with a low pressure transmission apparatus and with a flat-spread force measuring apparatus.
A force or pressure measuring device comprising a pot-like sensor body having a piston inserted thereto forming a narrow annular gap with opposing cylindrical surfaces of the interior of the sensor body and a space beneath the bottom end of said piston, the gap and the space being filled with elastomeric material strongly adhering to surfaces in contact therewith; a bottom wall of said sensor body being integrally formed as a diaphragm having pressure transducing elements applied thereto.
Such a force or pressure measuring device is used in devices provided with a low pressure transmission apparatus and with a flat-spread force measuring apparatus.
Description
Title:
Force or Pressure Measuring Device Field of the Invention The invention relates to a force or pressure measuring device and a flat-spread force measuring apparatus using such devices.
Background of the Art The U.S. Pat. Nos. 4,644,805, 4,739,666, 4,754,653, and 4,770,050 disclose force or pressure measuring devices comprising a pot-like housing in a cylindrical re~ess of which a piston is inserted forming a narrow annular gap with the cylindrical interior surfaces of the housing the gap being filled with elastomeric material strongly adhering to the contacting surfaces. A pressure sensor is in contact with the elastomeric material either by being embedded therein or by being exchangeably mounted with its force receiving element in contact with the elastomeric material through an opening provided in the housing. Such force measuring devices show high accuracy and low sensitivity against undesired lateral force components which are completely shunted from the piston through the elastomeric material onto the housing which is made of metal having appropriate elements for attaching the force measuring device to a measuring position and being provided with a cavity for receiving the pressure sensor and/or electronic components connected thereto.
Further embodiments disclosed in the above-mentioned U.S.
patents have a flat-spread form. Specifically, one embodiment just comprises two metal plates having a plurality of pressure sensors embedded in elastomeric material sandwiched therebetween. Problems may arise when forces are non-uniformly applied to the plates. Therefore, with further embodiments there is provided a flat-spread housing having a plane upper side with pistons inserted into recesses from the bottom side forming individual force measuring devices with their pressure sensors . ~ . .
.:- : .
`' ' .~. ~.......... . . .
203~133 ~eing connect.ed to an evaluation means for combining their readings.
Whilst these known force measuring devices have excellent operational characteristics they need separate pressure sensors either embedded in the elastomeric material or specifically mounted in an appropriately formed housing made of metal or polymeric concrete. Production of the known force measuring devices, assembly, and exchange of pressure sensors, are still complex and expensive. The U.S. Pat. No. 4,864,271 and the U.S.
Pat. Appl. S. N. 322,142, and S. N. 483,70~ assigned to the applicants disclose ceramic pressure sensors comprising a sensor body provided with an integral diaphragm having applied thereto a resistor bridge in thickfilm technique. Whilst such force measuring sensors are easy to manufacture, problems exist in mounting such sensors at appropriate measuring positions.
- British Pat. No. 1,065,192 discloses a pressure gauge using two plates of different area for pressure transmission with each of the two parallel plates being resiliently mounted and connected with each other by a rod. One of the plates forms part of a closed space filled with liquid and having arranged a pressure sensor therein. These known pressure gauges are of complex design and difficult to be manufactured.
German Laid Open Publication No. 25 28 242 discloses a flat-spread force measuring device comprising a force introduction plate supported at peripheral location distant from each other on flexible elements. Pressures exerted onto these elements are combined and communicated to a common force indicating device.
Summary of the Invention It is a principal object of the present invention to provide a force or pressure measuring device having a simple design.
It is another object of the present invention to provide a force measuring device insensitive against lateral forces and having a high accuracy.
'"''' ' ' ' ' :
.. . .
" '` ': : ' -3~ 3 ~
It is a still further object of the present invention to provide a force or pressure measuring device having a high pressure transmission ratio.
It is a still further object of the present invention to provide a flat-spread force measuring apparatus of simple design, simple manufacture, and permitting determination of the direction of force application.
The principal object of the invention is solved by a force or pressure r,leasuring device comprising a pot-like sensor body provided with a cylindrical recess; flange means integrally formed at an upper circumferential end of said body; a piston inserted into said recess forming a narrow annular gap with a cylindrical surface of said recess and a space between a bottom end surface of said piston and a bottom surface of said recess;
a diaphragm integrally formed in a bottom wall of said recess;
elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith; and pressure sensing means applied to a surface of said diaphragm.
According to another aspect of the invention there is provided a pressure measuring device comprising a housing having a central cylindrical recess the bottom of which being integrally formed as a diaphragm provided with pressure transducer elements; a piston inserted into said recess of said housing forming a narrow annular gap with an opposing cylindrical surface of said recess and a space between an end surface of said piston and said diaphragm; elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith; a pressure introducing plate attached to a free end of said piston; and wherein a cross-sectional area of said piston and an effective pressure area of said pressure introducing plate are of considerably different sizes.
According to still another aspect of the invention there is provided a flat-spread force measuring apparatus comprisin~ a plate-type base part provided with a plurality of recesses in : . . '-, . ~
.
.. ~ . .
-4- ~35133 peripheral proximity and distant from each other; piston means inserted into said recesses forming annular narrow gaps with opposing surfaces o~ said recesses; elastomeric material filled into said narrow gaps and strongly adhering to surfaces in contact therewith and spaces between bottom ends of said pistons and bottom walls of said recesses; and sensor means provided beneath said recesses for sensing forces applied to said piston means.
:' Brief Description of the D~awings Fig. l is a sectional view of a force or pressure measuring device according to a first embodiment;
Fig. 2 is a plan view from below onto the device of Fig. l;
- Fig. 3 is a sectional view of a second embodiment showing a pressure measuring device for low pressures;
Fig. 4 is a modification of the device of Fig. 3;
Figs. 5 and 6 are sectional views of further embodiments of force or pressure measuring devices according to the invention;
Fig. 7 is a schematic view illustrating the use of a device according to Fig. 4 or 6;
Fig. 8 is a perspectivic sectional view of an embodiment of a flat-spread force measuring apparatus according to the invention;
Fig. 9 is a perspectivic sectional view of a second embodiment of an apparatus similar to that of Fig. 8:
Fig. 10 is a vertical sectional view of the two embodiments of Figs. 8 and 9:
Fig. 11 is a plan view from below onto the embodiments of Fig.
lO: and Figs. 12 and 13 are vertical sectional views of essential portions of further embodiments of flat-spread force measuring apparatuses.
Force or Pressure Measuring Device Field of the Invention The invention relates to a force or pressure measuring device and a flat-spread force measuring apparatus using such devices.
Background of the Art The U.S. Pat. Nos. 4,644,805, 4,739,666, 4,754,653, and 4,770,050 disclose force or pressure measuring devices comprising a pot-like housing in a cylindrical re~ess of which a piston is inserted forming a narrow annular gap with the cylindrical interior surfaces of the housing the gap being filled with elastomeric material strongly adhering to the contacting surfaces. A pressure sensor is in contact with the elastomeric material either by being embedded therein or by being exchangeably mounted with its force receiving element in contact with the elastomeric material through an opening provided in the housing. Such force measuring devices show high accuracy and low sensitivity against undesired lateral force components which are completely shunted from the piston through the elastomeric material onto the housing which is made of metal having appropriate elements for attaching the force measuring device to a measuring position and being provided with a cavity for receiving the pressure sensor and/or electronic components connected thereto.
Further embodiments disclosed in the above-mentioned U.S.
patents have a flat-spread form. Specifically, one embodiment just comprises two metal plates having a plurality of pressure sensors embedded in elastomeric material sandwiched therebetween. Problems may arise when forces are non-uniformly applied to the plates. Therefore, with further embodiments there is provided a flat-spread housing having a plane upper side with pistons inserted into recesses from the bottom side forming individual force measuring devices with their pressure sensors . ~ . .
.:- : .
`' ' .~. ~.......... . . .
203~133 ~eing connect.ed to an evaluation means for combining their readings.
Whilst these known force measuring devices have excellent operational characteristics they need separate pressure sensors either embedded in the elastomeric material or specifically mounted in an appropriately formed housing made of metal or polymeric concrete. Production of the known force measuring devices, assembly, and exchange of pressure sensors, are still complex and expensive. The U.S. Pat. No. 4,864,271 and the U.S.
Pat. Appl. S. N. 322,142, and S. N. 483,70~ assigned to the applicants disclose ceramic pressure sensors comprising a sensor body provided with an integral diaphragm having applied thereto a resistor bridge in thickfilm technique. Whilst such force measuring sensors are easy to manufacture, problems exist in mounting such sensors at appropriate measuring positions.
- British Pat. No. 1,065,192 discloses a pressure gauge using two plates of different area for pressure transmission with each of the two parallel plates being resiliently mounted and connected with each other by a rod. One of the plates forms part of a closed space filled with liquid and having arranged a pressure sensor therein. These known pressure gauges are of complex design and difficult to be manufactured.
German Laid Open Publication No. 25 28 242 discloses a flat-spread force measuring device comprising a force introduction plate supported at peripheral location distant from each other on flexible elements. Pressures exerted onto these elements are combined and communicated to a common force indicating device.
Summary of the Invention It is a principal object of the present invention to provide a force or pressure measuring device having a simple design.
It is another object of the present invention to provide a force measuring device insensitive against lateral forces and having a high accuracy.
'"''' ' ' ' ' :
.. . .
" '` ': : ' -3~ 3 ~
It is a still further object of the present invention to provide a force or pressure measuring device having a high pressure transmission ratio.
It is a still further object of the present invention to provide a flat-spread force measuring apparatus of simple design, simple manufacture, and permitting determination of the direction of force application.
The principal object of the invention is solved by a force or pressure r,leasuring device comprising a pot-like sensor body provided with a cylindrical recess; flange means integrally formed at an upper circumferential end of said body; a piston inserted into said recess forming a narrow annular gap with a cylindrical surface of said recess and a space between a bottom end surface of said piston and a bottom surface of said recess;
a diaphragm integrally formed in a bottom wall of said recess;
elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith; and pressure sensing means applied to a surface of said diaphragm.
According to another aspect of the invention there is provided a pressure measuring device comprising a housing having a central cylindrical recess the bottom of which being integrally formed as a diaphragm provided with pressure transducer elements; a piston inserted into said recess of said housing forming a narrow annular gap with an opposing cylindrical surface of said recess and a space between an end surface of said piston and said diaphragm; elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith; a pressure introducing plate attached to a free end of said piston; and wherein a cross-sectional area of said piston and an effective pressure area of said pressure introducing plate are of considerably different sizes.
According to still another aspect of the invention there is provided a flat-spread force measuring apparatus comprisin~ a plate-type base part provided with a plurality of recesses in : . . '-, . ~
.
.. ~ . .
-4- ~35133 peripheral proximity and distant from each other; piston means inserted into said recesses forming annular narrow gaps with opposing surfaces o~ said recesses; elastomeric material filled into said narrow gaps and strongly adhering to surfaces in contact therewith and spaces between bottom ends of said pistons and bottom walls of said recesses; and sensor means provided beneath said recesses for sensing forces applied to said piston means.
:' Brief Description of the D~awings Fig. l is a sectional view of a force or pressure measuring device according to a first embodiment;
Fig. 2 is a plan view from below onto the device of Fig. l;
- Fig. 3 is a sectional view of a second embodiment showing a pressure measuring device for low pressures;
Fig. 4 is a modification of the device of Fig. 3;
Figs. 5 and 6 are sectional views of further embodiments of force or pressure measuring devices according to the invention;
Fig. 7 is a schematic view illustrating the use of a device according to Fig. 4 or 6;
Fig. 8 is a perspectivic sectional view of an embodiment of a flat-spread force measuring apparatus according to the invention;
Fig. 9 is a perspectivic sectional view of a second embodiment of an apparatus similar to that of Fig. 8:
Fig. 10 is a vertical sectional view of the two embodiments of Figs. 8 and 9:
Fig. 11 is a plan view from below onto the embodiments of Fig.
lO: and Figs. 12 and 13 are vertical sectional views of essential portions of further embodiments of flat-spread force measuring apparatuses.
2~135133 5 .
s~t Mode of Carrying out the Inv~ntion Fig. l illustrates a first embodiment of a force measuring device 1 of the invention. A force introducing piston 3 is inserted into a recess of a pot-like sensor body 2 preferably made of ceramic material, an annular gap 4 being formad between piston 3 and sensor body 2 (see U.S.Pat. No. 4,754,653). The annular gap 4 is very narrow though illustrated larger in Fig. 1 for sake of clarity. Sensor body 2 is formed integrally and has a rigid clamping ring 2a for fixing the sensor body 2 such that any clamping forces affecting the measurement will not be transmitted to force measuring elements. A relatively thin, flexible annular region 2b connected to clamping ring 2a forms the essential part of the annular gap 4 with the peripheral surface of piston 3, annular gap 4 being filled with elastomeric material 5, as silicone or natural rubber, fixedly adhering to contact surfaces by preferably being vulcanized thereto. Piston 3 has formed at its top a force introduction knob 9. At the other end of the annular region 2b there is provided a rigid ring 2c for mounting a relatively thin diaphragm 2d of a force or pressure sensor 25. Elastomeric material S is provided between the bottom end of piston 3 and diaphragm 2d such that a vertical force F urging against piston 3 is transmitted to diaphragm 2d essentially friction-free and in a proportional manner. Lateral force components are shunted through elastomeric material 5 onto sensor body 2 and the clamping thereof.
Diaphragm 2d will be slightly deformed upon loading causing changes in resistance of measuring resistors 6 attached to the bottom side of diaphragm 2d, as thickfilm resistors coated by a screen printing method (see Fig. 2). Contacts 7 connected to resistors 6 may be connected to a known evaluation circuit 16 (see Fig. 4) for transmitting any changes in resistance thereto.
According to Fig. 1 sensor body 2 is supported by a mounting ring 8 for connection to clamping ring 2a and leaving the diaphragm 2d freely movable. Mounting ring 8 and sensor body 2 '. : - . : ' :: :
2~3~ 33 may preferably be formed unitary, i. e. without any junction surface between support ring 8 and clamping ring 2a. As regards manufacture of the force meas~ring devices according to the invention, in particular the filling of the annular gap 4 with elastomeric material 5, it is referred to U.S. Pat.
No. 4,754,653. As regards the forming of a unitary ceramic pot-like sensor body 2 providsd with the diaphragm 2d it is referred to U.S. Pat. Appl. S. N. 483,704.
It should be noted that device 1 may be used ~or pressure measurement. In this case piston 3 may either be embedded in elastomeric material or the whole recess may be filled therewith omitting piston 3.
Fig. 3 illustrates an embodiment of a pressure measuring device 30 using a force measuring device 1 according to Fig. 1 with additional features for pressure transmission.
Specifically, the top end of piston 3 is attached to a flat-spread pressure introduction plate 10 having a considerably larger cross-sectional surface than piston 3. Accordingly, this embodiment is particularly adapted for measuring low pressures or low pressure differences, respectively. For example, depending on the area ratio of plate 10 and piston 3, an applied pressure p may be transmitted at a ratio of l : 50. Preferably, plate 10 will be formed integrally with piston 3; alternatively, piston 3 may be attached or screwed to the bottom side of plate lo the latter replacing the force introduction knob 9 of Fig. 1.
A second narrow annular gap 11 is formed between the peripheral surface of plate 10 and a housing ring 13 which again may be integral with a pot-like housing 32 (Fig. 3, on the left) or may be formed separately from housing 32 and connected thereto with a sealing 14 therebetween. Again, second annular gap ll is filled with elastomeric material 5 strongly adhering to ~urther contact surfaces. Below plate 10 there is provided a space 12 either filled with gas, loosely foamed material or the air removed from elastomeric material 5 during the filling-in into ~. ..
: , . . : - . : ::.
~.: , - .:
7 2~33~1 33 the gaps 4 and 11. Such a cushion does not affect a ~light vertical movement of piston 3 (and plate lo) upon loading but provides some attenuation.
As an alternative of such an embodiment a pressure measuring device could be designed for measuring extremely high pressures by having the effective area of plate 10 made essentially smaller than that of piston 3. Accordingly, the inner diameter of housing ring 13 will be selected smaller such that second gap 11 has a smaller ring diameter than first gap 4. For such a design the main portion of housing 32 should be separated from housing ring 13 for enabling inserting of piston 3.
The embodiment having a large flat-spread plate 10 is particularly adapted for measuring very small pressure differences or absolute pressures. The pressure measurement device of Fig. 3 may have various applications as measurement of liquid level in oil containers (see Fig. 7) permitting a continuous consumption measurement due to the extremely high response accuracy.
It should be noted that the bottom surface of housing 32 is plane such that it may conveniently be treated for application of resistors 6 preferably by screen printing.
Fig. 4 shows a modification of pressure measuring device 30 of Fig. 3. With this embodiment a pressure measuring device 35 has no second annular gap 11. Rather, a pressure introducing plate 40 is provided with a thinned annular region 40a permitting a small vertical movement of plate 40. Region 40a is integrally formed between a clamping ring 40b and a central portion 40c connected to piston 3. Projections 42e of housing 42 opposing the inner surface of region 40a may serve as a limiting and centering means. Clamping ring 4Ob may be connected to housing 42 by soldering or melting of a glass frit.
Preferably, ceramic plate 40 is formed integrally with piston 3 the combined element being placed onto green pot-like housing 42 . . i , .
.. :
2~3~ 3~
formed of ceramic material as well, followed by sintering to a single element. This results in a reduction of process steps and an a~solutely tight junction between housing 42 and clamping ring 4Ob.
Elastomeric material 5 is filled in into gap 4 through a radial bore 15 closed upon vulcanizing of elastomeric material ~. The remaining air forms gas cushion 12 mentioned above. On the plane bottom side of housing 42 an appropriate evaluation circuit 1 may directly be applied to the ceramic surface in addition to resistors 6 with a cover 19 hermetically sealing said circuit 16. For transmitting the pressure signal from diaphragm ~d a cable 17 extends to the exterior from evaluation circuit 16 through a tube 18 sealingly connected to cover 19. Tube 18 may serve both for cable guidance and protection and as a duct for applying atmospheric pressure.
Fig. 7 illustrates as an example an application of a pressure measuring device according to Fig. 3 or 4. Specifically, a hermetically sealed pressure measuring cell 90 according to Figs. 3, 4 (or 6) is lowered by means of tube 18 into a tank 20 for determining the static pressure p of liquid 21, related to the contents of the tank. In view of the very high accuracy and a high pressure transmission ratio pressure differences of l/lOOo bar may be measured. Thus, a continuous consumption measurement is possible with the readings displayed on an indicating device 22 connected to cable 17 and arranged at an exterior or even remote location. With the position of device 90 as shown in Fig. 7 and the mounting thereof at tube 18 no specific fixture is necessary. Furthermore, tube 18 permits lowering of the measuring device 90 to different depths and protecting of cable 17 therein.
Fig. 5 shows an embodiment of a force measuring device 250 using the principle explained in connection with the devices of Figs. 3 and 4 not for pressure transmission but for a lateral stabilization.
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9 203~ 33 The force measuring device 1 (see Fig. 1) is again inserted into a housing 51 with piston 3 being provided at its top side with a considerably expanded piston 50 guided in a corresponding cylindrical recess 50d in housing 51 forming again a second annular gap 50c filled with elastomeric material. An annular space 52 corresponding to space 12 (Fig. 3) may be connected to the atmosphere by means of a radial bore 52a.
In piston 50 there may be inserted a support element 50a holding preferably frictionlessly msvable a force introducing element 50b which may be a steel ball mounted in ball bearings or a peak of a cone or an edge of an edge element.
It should be noted that piston 50 has a relatively large height along the wall of recess 50d such that the influence of any lateral force components is excluded. Such lateral components may be considerably large without effecting the accuracy of vertical force measurement.
Exemplary and preferred dimensions of the various elements are:
diameter of piston 50 twice that of piston 3 and height of piston 3 half of or one diameter of piston 50. These dimensions depend on the field of application, specifically the total value of forces applied and their non-vertical portions and may vary by a factor of 0.3 to 3, preferably 0.5 to 2.
A further feature of the embodiment according to Fig. 5 is its standard or modular design as a force or pressure measuring sensor for various purposes. Housing 50 is formed like an ignition plug of a combustion motor with a base part 51a and a preferably threaded sensor head 51b which may have any desired design.
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Base part 51a serves as a mounting for receiving force measuring device 1 and houses an electronic sensor circuitry 53 connected to a supply cable 56 also used for output of the amplified sensor signal.
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~o- ~3~ 33 Cable 56 is introduced into s~ch ~ force or pressure measuring plug through a cover element 55 sealing by means o~ a sealing 55a circuitry 53 against the atmosphere.
Sensor head Slb may have various di~ferent designs. For example, piston 50 may have quite different diameters and heights and may be provided with various inserts 50a, 50b or may even be unitary provided with a force introducing knob at its top side.
Fixing of such a measuring plug at a force or pressure measuring position may be done by a threading 54 or a radial flange for attaching the device to an opening at ~hich pressure is present.
It should be noted that for pressure measurement sensor head 51b may be appropriately adapted, for instance according to a design similar to that of the embodiments of Figs. 3, 4, or 6.
Though as a material for the various elements as housing, pressure or force introducing piston, etc., ceramic material has been mentioned as a preferred material, for various embodiments different materials are applicable as well. An example is high-grade steel or a similar metal. This is particularly true for the pressure or force measuring plug according to Fig. 5.
Fig. 6 shows a simple embodiment of a pressure measuring box made of such metal. A pot-like housing 61 is covered by a diaphragm 60 connected to housing 61 by a weld seam 69.
Diaphragm 60 is a wave-type diaphragm having an intermediate region 60a of ring-type wa~es and ending in the center in a piston 63 representing the force introducing piston for the measuring device 1 of Fig. 1 mounted in a support 67 provided on the interior bottom of housing 61.
A circuit board or chip 66 for an electronic sensor circuitry may be arranged within housing 61 as well, connected to leads (not shown) extending through a tube 64 for power supply and sensor signal transmission. Tube 64 may be welded by a seam 65 to housing 61 and may be open to the atmosphere for measuring pressure differences applied to diaphragm 60.
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Alternatively, the interior of housing 61 may be evacuated or filled with a protection gas with the tube 64 closed such that absolute pressure is measured, as with a barometer.
Such a pressure measuring box according to Fig. 6 may be used with advantage for tank contents measureme~t as illustrated in Fig. 7. With tube 64 bent off by 90 the box may be placed onto the bottom of tank 20 such that even minimum levels may be determined.
With a modification of such a measuring box housing 61 may be provided in the region of welding seam 69 with a flange for attaching the box to a wall of tank 20, specifically the bottom wall, with diaphragm 60 covering an opening in the wall.
Specific applications would be contents measurement of fuel tanks, as of vehicles and airplanes.
Figs. 8, 10, and 11 (left-hand side) illustrate a flat-spread force measuring apparatus 101 having an annular base part 102 into which are fitted several pistons 103. For example, apparatus lol is provided with four pistons 103, Fig. 8 only showing three of them in view of the sectional illustration.
Pistons 103 are inserted into recesses 112 of base part 102 forming narrow annular gaps 104 illustrated enlarged in the drawing for sake of clarity. In reality, each annular gap 104 is very narrow and may have a width of about 0.2 to 2 mm depending on the dimensions of apparatus 101. Each annular gap 104 and a bottom region at the bottom side of piston 103 is filled with elastomeric material, indicated by dotted shadowing. The individual pistons 103 act onto a pressure sensor 105 each through the elastomeric material. With an annular equidistant arranqement of 90 each there are four sensor po~itions a, b, c, and d (with the fourth position d only shown in Fig. 11). ~or determining a force acting onto apparatus 101 through pistons 103 with elevated force introduction knobs 107, and the direction of said force, three sensor positions at an angular distance of 120 would be sufficient. Alternatively, more than four sensor positions may be provided, or the ring-type . .
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-12- ~ 3 3 diaphragm may be designed as uniform pressure sensor as disclosed in detail in U.s. Pat. No. 4,7~3,663.
Each pressure sensor 105 has a diaphragm 115 provided at its bottom surface with measuring resistors 10~. As indicated in Fig. 11, right-hand side, resistors 106 may be circuit-connected in a strain gauge bridge circuit and applied by thickfilm technology. Alternatively, any other known pressure transducers, for instance according to the piezoresistive principle may be used as pressure sensors loS. Preferably, diaphragm 115 is integral with base part 102 permitting production of this main element of apparatus 101 in one step for a plurality of sensor positions a, b, c, ... . According to the invention, the combined element is formed of ceramic material, as A1203, with the recesses 112 for receiving pistons 103 and integral diaphragms 115 being formed by pressing the green base part 102, followed by sintering the combined element at high temeratures.
Thus, base part 10~ may be provided quite simply with a plurality of diaphragms 115 uniformly distributed about a central passage 108.
Figs. 9, 10, and 11, right-hand side, illustrate a further embodiment as a modification of the embodiment just explained using a single piston formed as a ring 133 of a force measuring apparatus 131 which ring 133 being inserted into a complementary annular groove 143 provided in a base part 132 elastomeric material being filled in a U-form annular gap 144 formed between ring 133 and groove 143. Ring 133 thus forms a combination of a plurality of individual, locally discrete pistons 103 of Fig. 8.
Ring 133 acts onto a diaphragm 145 through the elastomeric material, diaphragm 145 forming the bottom of annular groove 143 prefexably having a uniform small wall thickness and being integral with base part 132. Measuring resistors 136 are applied to the bottom side of diaphragm 145 for forming discrete sensor portions at equidistant angular locations. Alternatively, it would be sufficient to form the bottom of groove 143 at at least ~,, ~........................................... . . . .
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three positions with reduced thickness such that these positions form diaphragms 145 at corresponding sensor positions a, b, c.
As may be seen from Fig. 9, by combining a plurality of pistons 103 to a unitary ring-type piston, as ring 133, production of apparatus 131 is further simplified since ring 133 is formed as a single integral element further simplifying filling-in of elastomeric material into groove 143. With diaphragm 145 provided over the whole bottom surface of base part 132 the number of sensor positions a, b, c, ... may be varied quite simply, as desired. Though with the embodiment base part 132 is shown as being provided with a central passage 138 apparatus 131 may be formed disk-like as well, i. e. without passage 138.
Accordingly, Fig. 10 shows a vertical section through the two embodiments explained above with a design having individual, locally discrete pistons 103 (left-hand side) and an integral ring 133 as a single piston (right-hand side). With the first embodiment (left-hand side) force introduction occurs through force introducing knobs 107 whilst with the second embodiment (right-hand side) force introduction to ring 133 may be accomplished through a ring-type seam 137.
Left-hand side of Fig. 10 illustrates the use of apparatus 101 as a support means of a machine part. Specifically, apparatus 101 is placed on a stationary base 109 whilst a support plate 10 is placed onto knobs 107 for determining a force F. Plate 10 may be part of a tooling machine or a vehicle or may be used for supporting a hydraulic cylinder. In order to prevent a lateral displacement of plate 10 with the force F
being oblique plate 10 is fitted into passage 108. Oblique force F loads sensor positions a, b, c, ... non-uniformly. Thus, from the differences of the individual vertical force components measured at the various sensor positions the direction of attack of force F may be determined when considering the dis~ances between the sensor positions. Thus, apparatus 101 may serve as a monitor for excessive lateral forces as well.
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Fig. 10, left-hand side, shows a modification of the embodiment of Fig. 8 with the pressure sensor being designed as an easily exchangeable pressure sensor 155 mounted in a frame 113 to base part 102. Pressure sensor 155 is in contact with the elastomeric material as explained in detail in U.S. Pat. No. 4,754,653.
However, the integral design of diaphragm 115 or 145, respectively, is preferred as shown in Fig. 8 and in Fig. 10, right-hand side, for the second embodiment.
In fact, this embodiment is illustrated in Fig. 10, right-hand side, in an enlarged size with ring 133 (see Fig. 9) fitted in into ring groove 143 and the diaphragm 145 being integrally formed at the bottom of base part 132. Seam 137 slightly projecting beyond base part 132 is loaded by a nut 116 via a threaded connection 111 extending through passage 138 loading seam 137. Apparatus 131 bears against an annular surface of ~
threaded bolt 122. Thus, apparatus 131 forms a type of washer directly determining the fixing force of nut 116. In view of the ring-type design of apparatus 131 having several angularly distributed sensor positions a, b, c, ... the uniformity of the fixing force in respect to the periphery of threaded connection 111 may be monitored.
In addition thereto, bending forces acting onto threaded connection 111 may be determined, f. i. if nut 116 is arranged stationary and is loaded through threaded bolt 122 as indicated by force arrow B in Fig. 10. By such bending forces the left portion of ring 133 would be loaded stronger than the right portion such that the right sensor position would determine a smaller loading than the left sensor position. Thus, both a qualitative and quantitative bending of threaded connection 111 may be monitored.
Fig. 11 illustrates a view from below of one half each onto the apparatuses 101 and 131 of Figs. 8 and 9 on the left-h~nd side and right-hand side, respectively. On the left-hand side of Fig. 11 discrete pistons 103 and gaps 104 are illustrated in .
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-15~ 3 ~i ~ 3 3 dashed lines whilst pressure sensor 115 mounted on frame 113 is shown in chain lines.
In Fig. 11, right-hand side, two sensor positions b' and c' are shown at an angular distance of 120 in order to illustrate a three sensor position configuration, i. e. together with a sensor position at a. Again, ring groove 134 and ring 133 are shown in dashed lines with the continuous diaphragm 145 formed at the bottom of base part 132. Of course, the more sensor positions are arranged the more accurate measurements are available. Even with a drop-out of one sensor position the device will still he operable.
Fig. 12 illustrates a modification of the embodiment of Fig. 8 using a force measuring device according to Fig. 1 with a sensor body 155 inserted at each sensor position.
Preferably, base part 122 may be formed ~rom ceramic material.
At each sensor position it is provided with a downward opening 157 with a diameter smaller than a cylindrical (or ring-type) recess 154 for receiving piston (or ring) 153. Pot-type sensor body 155 is inserted in opening 157 with its ring flange 156 engaging the bottom of recess 154 in base part 122.
As illustrated in more detail in Figs. 1 and 2, pressure sensor 155 is provided with a diaphragm 165 with elastomeric material filled between the surfaces of piston 153 and base part 122 and in the bottom area of piston 153 and an interior space 151 of sensor 155. The elastomeric material is filled in either prior to inserting sensor body 155 into the latter or after assembly of the force measuring apparatus, i. e. when filling elastomeric material into recess 154.
It should be noted that a plurality of sensor bodies 155 may be circumferentially arranged for the embodiments of Figs. 8 and 9.
Fig. 13 shows a modification of the embodiment of Fig. 12 using a pressure sensor 175 similar to that of Fig. 1 in a different arrangement. A base part 172 has cylindrical or U-type recesses ,- . -~. ,~ . ' ' ' ' . ,, ; : ~
16~ 3 ~ 1 3 3 with a piston or ring 173 inserted in a cylindrical (or ring-type) recess(es) 174.
~ith this embodiment, piston 173 is inserted into a two-step recess 182 formed on the bottom side into piston 173 and having inserted thereto a sensor body 185 an interior space 171 thereof being filled with elastomeric material which fills the bottom region and the vertical gaps as well. Diaphragm 175 of sensor body 185 spans over a free inner space 177 in recess 182 enabling diaphragm 175 to slightly bend upon force application.
Electrical leads (not shown) connect resistors 176 out of piston 173, preferably in upward direction, as far as no wireless signal transmission is used.
Again, as with the embodiment according to Fig. 8, the sensor positions may be locally restricted with a plurality of pressure sensors 185 circumferentially arranged in corresponding recesses 182 at the bottom side of piston 173.
It will be appreciated that such a design according to Fig. 13 results in particular simple and cost-effective production since both the base part and the ring-type piston may be formed in a simple pressing step of ceramic material followed by a sintering step. After insertion of pressure sensors 185 formed of ceramic as well, piston 173 is inserted into base part 172 combined with filling in elastomeric material in a bubblefree form as explained in detail in the above-mentioned U.S. Pat.
No. 4,754,653.
As regards the forming and sintering of the individual elements and combinations thereof of ceramic material it is referred to U.S. Pat. Appl. S. N. 483,704 assigned to the applicants.
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s~t Mode of Carrying out the Inv~ntion Fig. l illustrates a first embodiment of a force measuring device 1 of the invention. A force introducing piston 3 is inserted into a recess of a pot-like sensor body 2 preferably made of ceramic material, an annular gap 4 being formad between piston 3 and sensor body 2 (see U.S.Pat. No. 4,754,653). The annular gap 4 is very narrow though illustrated larger in Fig. 1 for sake of clarity. Sensor body 2 is formed integrally and has a rigid clamping ring 2a for fixing the sensor body 2 such that any clamping forces affecting the measurement will not be transmitted to force measuring elements. A relatively thin, flexible annular region 2b connected to clamping ring 2a forms the essential part of the annular gap 4 with the peripheral surface of piston 3, annular gap 4 being filled with elastomeric material 5, as silicone or natural rubber, fixedly adhering to contact surfaces by preferably being vulcanized thereto. Piston 3 has formed at its top a force introduction knob 9. At the other end of the annular region 2b there is provided a rigid ring 2c for mounting a relatively thin diaphragm 2d of a force or pressure sensor 25. Elastomeric material S is provided between the bottom end of piston 3 and diaphragm 2d such that a vertical force F urging against piston 3 is transmitted to diaphragm 2d essentially friction-free and in a proportional manner. Lateral force components are shunted through elastomeric material 5 onto sensor body 2 and the clamping thereof.
Diaphragm 2d will be slightly deformed upon loading causing changes in resistance of measuring resistors 6 attached to the bottom side of diaphragm 2d, as thickfilm resistors coated by a screen printing method (see Fig. 2). Contacts 7 connected to resistors 6 may be connected to a known evaluation circuit 16 (see Fig. 4) for transmitting any changes in resistance thereto.
According to Fig. 1 sensor body 2 is supported by a mounting ring 8 for connection to clamping ring 2a and leaving the diaphragm 2d freely movable. Mounting ring 8 and sensor body 2 '. : - . : ' :: :
2~3~ 33 may preferably be formed unitary, i. e. without any junction surface between support ring 8 and clamping ring 2a. As regards manufacture of the force meas~ring devices according to the invention, in particular the filling of the annular gap 4 with elastomeric material 5, it is referred to U.S. Pat.
No. 4,754,653. As regards the forming of a unitary ceramic pot-like sensor body 2 providsd with the diaphragm 2d it is referred to U.S. Pat. Appl. S. N. 483,704.
It should be noted that device 1 may be used ~or pressure measurement. In this case piston 3 may either be embedded in elastomeric material or the whole recess may be filled therewith omitting piston 3.
Fig. 3 illustrates an embodiment of a pressure measuring device 30 using a force measuring device 1 according to Fig. 1 with additional features for pressure transmission.
Specifically, the top end of piston 3 is attached to a flat-spread pressure introduction plate 10 having a considerably larger cross-sectional surface than piston 3. Accordingly, this embodiment is particularly adapted for measuring low pressures or low pressure differences, respectively. For example, depending on the area ratio of plate 10 and piston 3, an applied pressure p may be transmitted at a ratio of l : 50. Preferably, plate 10 will be formed integrally with piston 3; alternatively, piston 3 may be attached or screwed to the bottom side of plate lo the latter replacing the force introduction knob 9 of Fig. 1.
A second narrow annular gap 11 is formed between the peripheral surface of plate 10 and a housing ring 13 which again may be integral with a pot-like housing 32 (Fig. 3, on the left) or may be formed separately from housing 32 and connected thereto with a sealing 14 therebetween. Again, second annular gap ll is filled with elastomeric material 5 strongly adhering to ~urther contact surfaces. Below plate 10 there is provided a space 12 either filled with gas, loosely foamed material or the air removed from elastomeric material 5 during the filling-in into ~. ..
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7 2~33~1 33 the gaps 4 and 11. Such a cushion does not affect a ~light vertical movement of piston 3 (and plate lo) upon loading but provides some attenuation.
As an alternative of such an embodiment a pressure measuring device could be designed for measuring extremely high pressures by having the effective area of plate 10 made essentially smaller than that of piston 3. Accordingly, the inner diameter of housing ring 13 will be selected smaller such that second gap 11 has a smaller ring diameter than first gap 4. For such a design the main portion of housing 32 should be separated from housing ring 13 for enabling inserting of piston 3.
The embodiment having a large flat-spread plate 10 is particularly adapted for measuring very small pressure differences or absolute pressures. The pressure measurement device of Fig. 3 may have various applications as measurement of liquid level in oil containers (see Fig. 7) permitting a continuous consumption measurement due to the extremely high response accuracy.
It should be noted that the bottom surface of housing 32 is plane such that it may conveniently be treated for application of resistors 6 preferably by screen printing.
Fig. 4 shows a modification of pressure measuring device 30 of Fig. 3. With this embodiment a pressure measuring device 35 has no second annular gap 11. Rather, a pressure introducing plate 40 is provided with a thinned annular region 40a permitting a small vertical movement of plate 40. Region 40a is integrally formed between a clamping ring 40b and a central portion 40c connected to piston 3. Projections 42e of housing 42 opposing the inner surface of region 40a may serve as a limiting and centering means. Clamping ring 4Ob may be connected to housing 42 by soldering or melting of a glass frit.
Preferably, ceramic plate 40 is formed integrally with piston 3 the combined element being placed onto green pot-like housing 42 . . i , .
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formed of ceramic material as well, followed by sintering to a single element. This results in a reduction of process steps and an a~solutely tight junction between housing 42 and clamping ring 4Ob.
Elastomeric material 5 is filled in into gap 4 through a radial bore 15 closed upon vulcanizing of elastomeric material ~. The remaining air forms gas cushion 12 mentioned above. On the plane bottom side of housing 42 an appropriate evaluation circuit 1 may directly be applied to the ceramic surface in addition to resistors 6 with a cover 19 hermetically sealing said circuit 16. For transmitting the pressure signal from diaphragm ~d a cable 17 extends to the exterior from evaluation circuit 16 through a tube 18 sealingly connected to cover 19. Tube 18 may serve both for cable guidance and protection and as a duct for applying atmospheric pressure.
Fig. 7 illustrates as an example an application of a pressure measuring device according to Fig. 3 or 4. Specifically, a hermetically sealed pressure measuring cell 90 according to Figs. 3, 4 (or 6) is lowered by means of tube 18 into a tank 20 for determining the static pressure p of liquid 21, related to the contents of the tank. In view of the very high accuracy and a high pressure transmission ratio pressure differences of l/lOOo bar may be measured. Thus, a continuous consumption measurement is possible with the readings displayed on an indicating device 22 connected to cable 17 and arranged at an exterior or even remote location. With the position of device 90 as shown in Fig. 7 and the mounting thereof at tube 18 no specific fixture is necessary. Furthermore, tube 18 permits lowering of the measuring device 90 to different depths and protecting of cable 17 therein.
Fig. 5 shows an embodiment of a force measuring device 250 using the principle explained in connection with the devices of Figs. 3 and 4 not for pressure transmission but for a lateral stabilization.
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9 203~ 33 The force measuring device 1 (see Fig. 1) is again inserted into a housing 51 with piston 3 being provided at its top side with a considerably expanded piston 50 guided in a corresponding cylindrical recess 50d in housing 51 forming again a second annular gap 50c filled with elastomeric material. An annular space 52 corresponding to space 12 (Fig. 3) may be connected to the atmosphere by means of a radial bore 52a.
In piston 50 there may be inserted a support element 50a holding preferably frictionlessly msvable a force introducing element 50b which may be a steel ball mounted in ball bearings or a peak of a cone or an edge of an edge element.
It should be noted that piston 50 has a relatively large height along the wall of recess 50d such that the influence of any lateral force components is excluded. Such lateral components may be considerably large without effecting the accuracy of vertical force measurement.
Exemplary and preferred dimensions of the various elements are:
diameter of piston 50 twice that of piston 3 and height of piston 3 half of or one diameter of piston 50. These dimensions depend on the field of application, specifically the total value of forces applied and their non-vertical portions and may vary by a factor of 0.3 to 3, preferably 0.5 to 2.
A further feature of the embodiment according to Fig. 5 is its standard or modular design as a force or pressure measuring sensor for various purposes. Housing 50 is formed like an ignition plug of a combustion motor with a base part 51a and a preferably threaded sensor head 51b which may have any desired design.
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Base part 51a serves as a mounting for receiving force measuring device 1 and houses an electronic sensor circuitry 53 connected to a supply cable 56 also used for output of the amplified sensor signal.
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~o- ~3~ 33 Cable 56 is introduced into s~ch ~ force or pressure measuring plug through a cover element 55 sealing by means o~ a sealing 55a circuitry 53 against the atmosphere.
Sensor head Slb may have various di~ferent designs. For example, piston 50 may have quite different diameters and heights and may be provided with various inserts 50a, 50b or may even be unitary provided with a force introducing knob at its top side.
Fixing of such a measuring plug at a force or pressure measuring position may be done by a threading 54 or a radial flange for attaching the device to an opening at ~hich pressure is present.
It should be noted that for pressure measurement sensor head 51b may be appropriately adapted, for instance according to a design similar to that of the embodiments of Figs. 3, 4, or 6.
Though as a material for the various elements as housing, pressure or force introducing piston, etc., ceramic material has been mentioned as a preferred material, for various embodiments different materials are applicable as well. An example is high-grade steel or a similar metal. This is particularly true for the pressure or force measuring plug according to Fig. 5.
Fig. 6 shows a simple embodiment of a pressure measuring box made of such metal. A pot-like housing 61 is covered by a diaphragm 60 connected to housing 61 by a weld seam 69.
Diaphragm 60 is a wave-type diaphragm having an intermediate region 60a of ring-type wa~es and ending in the center in a piston 63 representing the force introducing piston for the measuring device 1 of Fig. 1 mounted in a support 67 provided on the interior bottom of housing 61.
A circuit board or chip 66 for an electronic sensor circuitry may be arranged within housing 61 as well, connected to leads (not shown) extending through a tube 64 for power supply and sensor signal transmission. Tube 64 may be welded by a seam 65 to housing 61 and may be open to the atmosphere for measuring pressure differences applied to diaphragm 60.
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Alternatively, the interior of housing 61 may be evacuated or filled with a protection gas with the tube 64 closed such that absolute pressure is measured, as with a barometer.
Such a pressure measuring box according to Fig. 6 may be used with advantage for tank contents measureme~t as illustrated in Fig. 7. With tube 64 bent off by 90 the box may be placed onto the bottom of tank 20 such that even minimum levels may be determined.
With a modification of such a measuring box housing 61 may be provided in the region of welding seam 69 with a flange for attaching the box to a wall of tank 20, specifically the bottom wall, with diaphragm 60 covering an opening in the wall.
Specific applications would be contents measurement of fuel tanks, as of vehicles and airplanes.
Figs. 8, 10, and 11 (left-hand side) illustrate a flat-spread force measuring apparatus 101 having an annular base part 102 into which are fitted several pistons 103. For example, apparatus lol is provided with four pistons 103, Fig. 8 only showing three of them in view of the sectional illustration.
Pistons 103 are inserted into recesses 112 of base part 102 forming narrow annular gaps 104 illustrated enlarged in the drawing for sake of clarity. In reality, each annular gap 104 is very narrow and may have a width of about 0.2 to 2 mm depending on the dimensions of apparatus 101. Each annular gap 104 and a bottom region at the bottom side of piston 103 is filled with elastomeric material, indicated by dotted shadowing. The individual pistons 103 act onto a pressure sensor 105 each through the elastomeric material. With an annular equidistant arranqement of 90 each there are four sensor po~itions a, b, c, and d (with the fourth position d only shown in Fig. 11). ~or determining a force acting onto apparatus 101 through pistons 103 with elevated force introduction knobs 107, and the direction of said force, three sensor positions at an angular distance of 120 would be sufficient. Alternatively, more than four sensor positions may be provided, or the ring-type . .
.:: . : .
-12- ~ 3 3 diaphragm may be designed as uniform pressure sensor as disclosed in detail in U.s. Pat. No. 4,7~3,663.
Each pressure sensor 105 has a diaphragm 115 provided at its bottom surface with measuring resistors 10~. As indicated in Fig. 11, right-hand side, resistors 106 may be circuit-connected in a strain gauge bridge circuit and applied by thickfilm technology. Alternatively, any other known pressure transducers, for instance according to the piezoresistive principle may be used as pressure sensors loS. Preferably, diaphragm 115 is integral with base part 102 permitting production of this main element of apparatus 101 in one step for a plurality of sensor positions a, b, c, ... . According to the invention, the combined element is formed of ceramic material, as A1203, with the recesses 112 for receiving pistons 103 and integral diaphragms 115 being formed by pressing the green base part 102, followed by sintering the combined element at high temeratures.
Thus, base part 10~ may be provided quite simply with a plurality of diaphragms 115 uniformly distributed about a central passage 108.
Figs. 9, 10, and 11, right-hand side, illustrate a further embodiment as a modification of the embodiment just explained using a single piston formed as a ring 133 of a force measuring apparatus 131 which ring 133 being inserted into a complementary annular groove 143 provided in a base part 132 elastomeric material being filled in a U-form annular gap 144 formed between ring 133 and groove 143. Ring 133 thus forms a combination of a plurality of individual, locally discrete pistons 103 of Fig. 8.
Ring 133 acts onto a diaphragm 145 through the elastomeric material, diaphragm 145 forming the bottom of annular groove 143 prefexably having a uniform small wall thickness and being integral with base part 132. Measuring resistors 136 are applied to the bottom side of diaphragm 145 for forming discrete sensor portions at equidistant angular locations. Alternatively, it would be sufficient to form the bottom of groove 143 at at least ~,, ~........................................... . . . .
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three positions with reduced thickness such that these positions form diaphragms 145 at corresponding sensor positions a, b, c.
As may be seen from Fig. 9, by combining a plurality of pistons 103 to a unitary ring-type piston, as ring 133, production of apparatus 131 is further simplified since ring 133 is formed as a single integral element further simplifying filling-in of elastomeric material into groove 143. With diaphragm 145 provided over the whole bottom surface of base part 132 the number of sensor positions a, b, c, ... may be varied quite simply, as desired. Though with the embodiment base part 132 is shown as being provided with a central passage 138 apparatus 131 may be formed disk-like as well, i. e. without passage 138.
Accordingly, Fig. 10 shows a vertical section through the two embodiments explained above with a design having individual, locally discrete pistons 103 (left-hand side) and an integral ring 133 as a single piston (right-hand side). With the first embodiment (left-hand side) force introduction occurs through force introducing knobs 107 whilst with the second embodiment (right-hand side) force introduction to ring 133 may be accomplished through a ring-type seam 137.
Left-hand side of Fig. 10 illustrates the use of apparatus 101 as a support means of a machine part. Specifically, apparatus 101 is placed on a stationary base 109 whilst a support plate 10 is placed onto knobs 107 for determining a force F. Plate 10 may be part of a tooling machine or a vehicle or may be used for supporting a hydraulic cylinder. In order to prevent a lateral displacement of plate 10 with the force F
being oblique plate 10 is fitted into passage 108. Oblique force F loads sensor positions a, b, c, ... non-uniformly. Thus, from the differences of the individual vertical force components measured at the various sensor positions the direction of attack of force F may be determined when considering the dis~ances between the sensor positions. Thus, apparatus 101 may serve as a monitor for excessive lateral forces as well.
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Fig. 10, left-hand side, shows a modification of the embodiment of Fig. 8 with the pressure sensor being designed as an easily exchangeable pressure sensor 155 mounted in a frame 113 to base part 102. Pressure sensor 155 is in contact with the elastomeric material as explained in detail in U.S. Pat. No. 4,754,653.
However, the integral design of diaphragm 115 or 145, respectively, is preferred as shown in Fig. 8 and in Fig. 10, right-hand side, for the second embodiment.
In fact, this embodiment is illustrated in Fig. 10, right-hand side, in an enlarged size with ring 133 (see Fig. 9) fitted in into ring groove 143 and the diaphragm 145 being integrally formed at the bottom of base part 132. Seam 137 slightly projecting beyond base part 132 is loaded by a nut 116 via a threaded connection 111 extending through passage 138 loading seam 137. Apparatus 131 bears against an annular surface of ~
threaded bolt 122. Thus, apparatus 131 forms a type of washer directly determining the fixing force of nut 116. In view of the ring-type design of apparatus 131 having several angularly distributed sensor positions a, b, c, ... the uniformity of the fixing force in respect to the periphery of threaded connection 111 may be monitored.
In addition thereto, bending forces acting onto threaded connection 111 may be determined, f. i. if nut 116 is arranged stationary and is loaded through threaded bolt 122 as indicated by force arrow B in Fig. 10. By such bending forces the left portion of ring 133 would be loaded stronger than the right portion such that the right sensor position would determine a smaller loading than the left sensor position. Thus, both a qualitative and quantitative bending of threaded connection 111 may be monitored.
Fig. 11 illustrates a view from below of one half each onto the apparatuses 101 and 131 of Figs. 8 and 9 on the left-h~nd side and right-hand side, respectively. On the left-hand side of Fig. 11 discrete pistons 103 and gaps 104 are illustrated in .
:
-15~ 3 ~i ~ 3 3 dashed lines whilst pressure sensor 115 mounted on frame 113 is shown in chain lines.
In Fig. 11, right-hand side, two sensor positions b' and c' are shown at an angular distance of 120 in order to illustrate a three sensor position configuration, i. e. together with a sensor position at a. Again, ring groove 134 and ring 133 are shown in dashed lines with the continuous diaphragm 145 formed at the bottom of base part 132. Of course, the more sensor positions are arranged the more accurate measurements are available. Even with a drop-out of one sensor position the device will still he operable.
Fig. 12 illustrates a modification of the embodiment of Fig. 8 using a force measuring device according to Fig. 1 with a sensor body 155 inserted at each sensor position.
Preferably, base part 122 may be formed ~rom ceramic material.
At each sensor position it is provided with a downward opening 157 with a diameter smaller than a cylindrical (or ring-type) recess 154 for receiving piston (or ring) 153. Pot-type sensor body 155 is inserted in opening 157 with its ring flange 156 engaging the bottom of recess 154 in base part 122.
As illustrated in more detail in Figs. 1 and 2, pressure sensor 155 is provided with a diaphragm 165 with elastomeric material filled between the surfaces of piston 153 and base part 122 and in the bottom area of piston 153 and an interior space 151 of sensor 155. The elastomeric material is filled in either prior to inserting sensor body 155 into the latter or after assembly of the force measuring apparatus, i. e. when filling elastomeric material into recess 154.
It should be noted that a plurality of sensor bodies 155 may be circumferentially arranged for the embodiments of Figs. 8 and 9.
Fig. 13 shows a modification of the embodiment of Fig. 12 using a pressure sensor 175 similar to that of Fig. 1 in a different arrangement. A base part 172 has cylindrical or U-type recesses ,- . -~. ,~ . ' ' ' ' . ,, ; : ~
16~ 3 ~ 1 3 3 with a piston or ring 173 inserted in a cylindrical (or ring-type) recess(es) 174.
~ith this embodiment, piston 173 is inserted into a two-step recess 182 formed on the bottom side into piston 173 and having inserted thereto a sensor body 185 an interior space 171 thereof being filled with elastomeric material which fills the bottom region and the vertical gaps as well. Diaphragm 175 of sensor body 185 spans over a free inner space 177 in recess 182 enabling diaphragm 175 to slightly bend upon force application.
Electrical leads (not shown) connect resistors 176 out of piston 173, preferably in upward direction, as far as no wireless signal transmission is used.
Again, as with the embodiment according to Fig. 8, the sensor positions may be locally restricted with a plurality of pressure sensors 185 circumferentially arranged in corresponding recesses 182 at the bottom side of piston 173.
It will be appreciated that such a design according to Fig. 13 results in particular simple and cost-effective production since both the base part and the ring-type piston may be formed in a simple pressing step of ceramic material followed by a sintering step. After insertion of pressure sensors 185 formed of ceramic as well, piston 173 is inserted into base part 172 combined with filling in elastomeric material in a bubblefree form as explained in detail in the above-mentioned U.S. Pat.
No. 4,754,653.
As regards the forming and sintering of the individual elements and combinations thereof of ceramic material it is referred to U.S. Pat. Appl. S. N. 483,704 assigned to the applicants.
:: . . : , - . .
: - - .
Claims (19)
1. A force or pressure measuring device comprising:
a pot-like sensor body provided with a cylindrical recess;
flange means integrally formed at an upper circumferential end of said body;
a piston inserted into said recess forming a narrow annular gap with a cylindrical surface of said recess and a space between a bottom end surface of said piston and a bottom surface of said recess;
a diaphragm integrally formed in a bottom wall of said recess;
elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith; and pressure sensing means applied to a surface of said diaphragm.
a pot-like sensor body provided with a cylindrical recess;
flange means integrally formed at an upper circumferential end of said body;
a piston inserted into said recess forming a narrow annular gap with a cylindrical surface of said recess and a space between a bottom end surface of said piston and a bottom surface of said recess;
a diaphragm integrally formed in a bottom wall of said recess;
elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith; and pressure sensing means applied to a surface of said diaphragm.
2. The device of claim 1, wherein said sensor body further comprises:
a flexible cylindrical portion connected to said flange means at one end thereof; and a rigid diaphragm supporting ring connected to an opposite end of said flexible cylindrical portion:
said sensor body being integrally formed of ceramic material.
a flexible cylindrical portion connected to said flange means at one end thereof; and a rigid diaphragm supporting ring connected to an opposite end of said flexible cylindrical portion:
said sensor body being integrally formed of ceramic material.
3. A pressure measuring device comprising:
a housing having a central cylindrical recess the bottom of which being integrally formed as a diaphragm provided with pressure transducer elements, a piston inserted into said recess of said housing forming a narrow annular gap with an opposing cylindrical surface of said recess and a space between an end surface of said piston and said diaphragm;
elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith;
a pressure introducing plate attached to a free end of said piston; and wherein a cross sectional area of said piston and an effective pressure area of said pressure introducing plate are of considerably different sizes.
a housing having a central cylindrical recess the bottom of which being integrally formed as a diaphragm provided with pressure transducer elements, a piston inserted into said recess of said housing forming a narrow annular gap with an opposing cylindrical surface of said recess and a space between an end surface of said piston and said diaphragm;
elastomeric material filling said gap and said space and strongly adhering to surfaces in contact therewith;
a pressure introducing plate attached to a free end of said piston; and wherein a cross sectional area of said piston and an effective pressure area of said pressure introducing plate are of considerably different sizes.
4. The device of claim 3, wherein a peripheral cylindrical surface of said pressure introducing plate forms a further narrow annular gap with a cylindrical surface of an expanded portion of said recess of said housing said narrow annular gap being filled with elastomeric material strongly adhering to surfaces in contact therewith, a free space being formed between a bottom surface of said expanded portion and a bottom end surface of said pressure introducing plate.
5. The device of claim 3, wherein said force introducing plate is at least partially formed as a flexible diaphragm rigidly connected to a circumferential end edge of said housing, a free space being formed below said flexible portions permitting bending of said diaphragm, said piston being centrally fixed to a bottom side of said diaphragm.
6. The device of claim 5, further comprising a tube connected to said housing said tube being adapted for receiving a power supply/signal cable connected to electronic circuitry mounted in a further space of said housing and connected to said pressure sensor means.
7. The device of claim 6, wherein said tube has a length permitting positioning of said pressure measuring device at a desired height within a liquid tank.
8. The device of claim 6, wherein said housing is circumferentially provided with flange means for mounting said device to an opening of a tank means.
9. The device of claim 1 further comprising:
a tube-type housing provided at one end thereof with means for supporting and receiving said sensor body; and a sensor head means attachable to said one end of said housing said piston being associated with said sensor head means.
a tube-type housing provided at one end thereof with means for supporting and receiving said sensor body; and a sensor head means attachable to said one end of said housing said piston being associated with said sensor head means.
10. The device of claim 9, wherein said housing sealingly encloses an electronic sensor circuitry.
11. The device of claim 9 wherein a cylindrical extension of said piston is inserted into a recess formed in said sensor head means, and forming a further annular narrow gap of essential height with a peripheral surface of said piston extension said gap being filled with elastomeric material strongly adhering to surfaces in contact therewith, said piston extension having a considerably larger diameter than said piston.
12. The device of claim 9, wherein said sensor head means is provided with means for attaching said device to a measuring position.
13. The device of claim 11, wherein said piston extension is provided with force introducing means at an end side opposite to a piston end side.
14. A flat-spread force measuring apparatus comprising:
a plate-type base part provided with a plurality of recesses in peripheral proximity and distant from each other;
piston means inserted into said recesses forming annular narrow gaps with opposing surfaces of said recesses;
elastomeric material filled into said narrow gaps and strongly adhering to surfaces in contact therewith and spaces between bottom ends of said pistons and bottom walls of said recesses: and sensor means provided beneath said recesses for sensing forces applied to said piston means.
a plate-type base part provided with a plurality of recesses in peripheral proximity and distant from each other;
piston means inserted into said recesses forming annular narrow gaps with opposing surfaces of said recesses;
elastomeric material filled into said narrow gaps and strongly adhering to surfaces in contact therewith and spaces between bottom ends of said pistons and bottom walls of said recesses: and sensor means provided beneath said recesses for sensing forces applied to said piston means.
15. The apparatus of claim 14, wherein said bottom walls of said recesses are formed as a diaphragm having pressure transducer elements applied thereto.
16. The apparatus of claim 14, wherein said bottom wall is provided with openings and said pressure sensor means are discrete pressure sensors attached to said openings in pressure transmitting contact to said elastomeric material.
17. The apparatus of claim 14, wherein said plurality of recesses is formed to a continuous ring groove receiving a ring-type piston forming inner and outer annular narrow gaps and a bottom space with opposing surfaces of said ring groove, said gaps and said space being filled with elastomeric material strongly adhering to surfaces in contact therewith, said ring groove having a bottom wall formed as a pressure transmitting means for transmitting pressure to pressure transducer elements in contact therewith.
18. The apparatus of claim 17, wherein said bottom wall is formed at least at a plurality of angular equidistant positions as a diaphragm having pressure transducer elements applied thereto.
19. The apparatus of claim 14, wherein said pistons are provided at a top end thereof with means for force introduction.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19904003048 DE4003048A1 (en) | 1990-02-02 | 1990-02-02 | Diaphragm force or pressure transducer |
| DEP4003048.2 | 1990-02-02 | ||
| DEP4023747.8 | 1990-07-26 | ||
| DE19904023747 DE4023747A1 (en) | 1990-07-26 | 1990-07-26 | Diaphragm force or pressure transducer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2035133A1 true CA2035133A1 (en) | 1991-08-03 |
Family
ID=25889642
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002035133A Abandoned CA2035133A1 (en) | 1990-02-02 | 1991-01-29 | Force or pressure measuring device |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0440011A3 (en) |
| JP (1) | JPH0599769A (en) |
| KR (1) | KR910021574A (en) |
| CA (1) | CA2035133A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111426417A (en) * | 2019-01-09 | 2020-07-17 | 上海常衡电子科技有限公司 | Pressure detection sensor and constant pressure welding device |
| US20230014532A1 (en) * | 2021-07-16 | 2023-01-19 | Nidec-Shimpo Corporation | External gear, wave decelerator, and robot |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4421959A1 (en) * | 1994-06-23 | 1996-01-04 | Fischer Artur Werke Gmbh | Preload control element for screw anchors |
| DE19953617A1 (en) * | 1999-11-08 | 2001-05-10 | Robert Seuffer Gmbh & Co | Distance measuring device |
| AU2001278715A1 (en) * | 2000-08-10 | 2002-02-25 | Nok Corporation | Pressure sensor |
| DE102005059938B4 (en) * | 2005-12-13 | 2020-10-15 | Jörg Hohmann | Screw connection |
| DE102006004086A1 (en) * | 2006-01-25 | 2007-08-09 | Quantum Hydrometrie Gesellschaft für Meß- und Systemtechnik mbH | Level measuring device for measuring a filling or water level |
| FR2933035B1 (en) * | 2008-06-26 | 2011-11-04 | Michelin Soc Tech | PRESSURE MEASURING DEVICE AND MOLD FOR VULCANIZING A TIRE GUM |
| WO2013064590A1 (en) * | 2011-11-02 | 2013-05-10 | Sanofi-Aventis Deutschland Gmbh | Piston for a cartridge for use in a drug delivery device |
| DE102011089608A1 (en) * | 2011-12-22 | 2013-06-27 | Horst Siedle Gmbh & Co. Kg | Housing part for an electrical sensor and method for producing the housing part |
| DE102012104366A1 (en) * | 2012-05-21 | 2013-11-21 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Anströmrichtungssensoreinrichtung and Anströmrichtungserfassungseinrichtung |
| DE102014009847B4 (en) * | 2014-07-02 | 2018-03-22 | Hottinger Baldwin Messtechnik Gmbh | Load cell with hydraulic centering device |
| US10094726B2 (en) * | 2017-02-01 | 2018-10-09 | Honeywell International Inc. | Membrane isolated, gel-filled force sensor |
| EP4071450B1 (en) | 2021-04-07 | 2024-02-28 | TE Connectivity Solutions GmbH | Load cell with a force transmitting element held by a gel element |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3604420A1 (en) * | 1986-01-24 | 1987-08-20 | Pfister Gmbh | Large-area force-measuring appliance |
| EP0205509B1 (en) * | 1984-12-10 | 1989-05-31 | Pfister GmbH | Force measuring device |
| DE3534211A1 (en) * | 1985-09-25 | 1987-03-26 | Pfister Gmbh | MOTOR VEHICLE AND METHOD FOR OPERATING IT |
| JPS63292032A (en) * | 1987-05-26 | 1988-11-29 | Ngk Insulators Ltd | Pressure detector |
| US4864874A (en) * | 1987-08-05 | 1989-09-12 | Pfister Gmbh | Force measuring device |
| DE3919411A1 (en) * | 1989-03-07 | 1990-12-20 | Pfister Gmbh | PRESSURE SENSOR AND RELATED PRODUCTION PROCESS |
-
1991
- 1991-01-02 EP EP19910100006 patent/EP0440011A3/en not_active Withdrawn
- 1991-01-29 CA CA002035133A patent/CA2035133A1/en not_active Abandoned
- 1991-02-01 JP JP3054192A patent/JPH0599769A/en active Pending
- 1991-02-02 KR KR1019910001836A patent/KR910021574A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111426417A (en) * | 2019-01-09 | 2020-07-17 | 上海常衡电子科技有限公司 | Pressure detection sensor and constant pressure welding device |
| US20230014532A1 (en) * | 2021-07-16 | 2023-01-19 | Nidec-Shimpo Corporation | External gear, wave decelerator, and robot |
| US12186902B2 (en) * | 2021-07-16 | 2025-01-07 | Nidec-Shimpo Corporation | External gear, wave decelerator, and robot |
Also Published As
| Publication number | Publication date |
|---|---|
| KR910021574A (en) | 1991-12-20 |
| EP0440011A3 (en) | 1992-06-03 |
| EP0440011A2 (en) | 1991-08-07 |
| JPH0599769A (en) | 1993-04-23 |
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