DE102018206273B4 - Measuring instrument for measuring a normal force acting on an electrical contact and a method for this - Google Patents

Abstract

Measuring instrument (1) for measuring a normal force (N) acting on at least one contact point (81) of an electrical contact (78), with at least two measuring arms (2, 2 ') running next to one another, with at least one measuring arm (2, 2') at least is provided with at least one normal force sensor (12) at the at least one contact point (81), characterized in that the measuring instrument (1) has a position between the measuring arms (2, 2 ') in an insertion direction (E) essentially perpendicular to the normal force (N ) has insertable slide (4).

Description

The invention relates to a measuring instrument for measuring a normal force acting on at least one contact point of an electrical contact, with at least two measuring arms running next to one another, at least one measuring arm being provided with a normal force sensor at least at the contact point. The invention also relates to a method for measuring a normal force acting on at least one contact point of an electrical contact.

The measurement of a normal force is particularly important in the case of plug connections between plugs and their mating plugs. The normal force denotes the force that a connector exerts at one or more contact points on the electrical contact of the mating connector perpendicular to the longitudinal direction of the electrical contact, that is, perpendicular to the plug-in direction. Too high a normal force leads to a higher frictional force, higher insertion force and thus to a short service life of the connector. Too little normal force results in loose contact. The contact that is too loose can lead to fretting corrosion and that existing layers of corrosion, absorption and / or contamination cannot be penetrated, which can lead to a poor connection between the plug and the mating plug. The normal force that acts on the electrical contact can vary from contact point to contact point. It is therefore important to check the normal forces acting on the electrical contact at the individual contact points in order to ensure that the plug is fully functional. These plugs are preferably checked for normal force during production, in addition to a 100% visual inspection, in order to deliver them certified. Errors in the production lines are recognized early and immediately, which means that the number of faulty plugs is reduced and the risk of faulty goods being delivered to customers is reduced. Furthermore, tolerance windows for the optical control can be widened in order to increase productivity.

A measuring system for measuring forces, such as spring forces in plug connections, is for example in the DE 10 2016 226 282 A1 shown. In the measuring system, a measuring element has an advantageous geometric design to assume a plurality of mechanical states which correspond to a plurality of measuring ranges.

In the DE 40 03 552 A1 a device for measuring the contact force acting from contact spring arms of an electrical contact element of an electrical plug connection on a contact element of an electrical counter-contact part with a probe made of hard metal is shown. In the DD 2 02 758 A1 a force transducer consists of a magnetic circuit designed with a measuring tip adapted to a measurement object, which is provided with at least one active winding.

Further contact sensors are in the U.S. 5,086,652 A , U.S. 5,024,106 A and U.S. 4,380,171 A shown.

In the U.S. 5,086,652 A the contact sensor is formed from a pair of thin flexible insulating foils which have a plurality of elongated flexible leads. The supply lines are each connected to a single connection and thus have an independent detection field.

The U.S. 5,024,106 A shows a contact sensor with a silicon element, in the edge surface of which a piezoresistive sensor area diffuses, which changes the resistance as a function of a stress on the silicon element caused by a normal force.

In the U.S. 4,380,171 A For example, the contact sensor is mounted in a multi-terminal circuit board connector with the measured force normally applied to a surface of a circuit board received in the connector.

In a previous method for measuring the normal force, a measuring instrument with approximately the same dimensions as the electrical contact of a mating connector is inserted into a connector, the mating connector being provided with at least one force- or pressure-sensitive normal force sensor. However, the insertion of the measuring instrument leads to abrasion and wear of the contact points of the plug and the measuring instrument. Depending on the design, the insertion track is registered by the normal force sensor and can lead to inaccuracy in the evaluation of the measurement results.

It is therefore the object of the invention to create a measuring instrument and a method by means of which the normal force at a contact point of a plug, in particular at a large number of contact points, can be measured more simply, more cost-effectively and more accurately.

The object is achieved by the present invention in that the measuring instrument has at least one slide that can be inserted between the measuring arms in an insertion direction.

• - Einstecken zweier Messarme in den zu prüfenden Stecker;
• - Einschieben eines Schiebers zwischen die Messarme;
• - Messen der Normalkraft an zumindest einer mit zumindest einem Normalkraftsensor versehenen Kontaktstelle eines Messarms.

A method according to the invention comprises the following steps:

• - Inserting two measuring arms into the connector to be tested;
• - inserting a slide between the measuring arms;
• - Measuring the normal force at at least one contact point of a measuring arm provided with at least one normal force sensor.

With the solution according to the invention, the measuring arms can be plugged into the plug with little or no frictional resistance. This reduces the wear and tear on the plug and shows no signs of use due to the test. Furthermore, no insertion track is recorded by the at least one normal force sensor. The slide that can be inserted between the measuring arms can be used to simulate the mechanical properties, such as the hardness, and the dimensions of the electrical contact of a mating connector. This enables a simple, inexpensive and precise measurement of the normal forces that would act on an electrical contact of a mating connector.

In the following, advantageous developments and refinements are described which can be combined with one another as required.

The plug as used here can apply to male as well as female plug shapes.

The electrical contact as used here can relate to both male and female forms of electrical contact.

The plug can in particular be a socket contact and the electrical contact of the mating connector can in particular be a contact pin. The measuring instrument can simulate the dimensions and shape of the contact pin at least in a measuring section plugged into the plug with the slide inserted so that an accurate and representative measurement of the normal forces acting on the contact points can take place. The contact points of the electrical contact can correspond to the contact points of the measuring arms. The contact pin can have a rectangular, square, elliptical or round cross section.

When the slide is inserted, the measuring section can have the same cross section as the contact pin.

The at least one normal force sensor can be a piezoelectric or piezoresistive sensor which is arranged on at least one measuring arm. The sensor can convert the normal force acting on the sensor directly into an electrical signal. In a piezoresistive sensor, an acting force or pressure leads to a change in the resistance, which can be directly reflected. This enables direct measurement of the normal force acting at a contact point.

In a further advantageous embodiment, at least two measuring arms can be arranged parallel to one another when a slide is inserted. This ensures that the contact points are contacted evenly.

At least two measuring arms can be arranged parallel to one another at least in sections and can be spaced apart from one another at least in sections in the direction of the normal force. The clear width in the direction of the normal force of the section in which the measuring arms are spaced from one another can preferably be greater than the material thickness of the slide. In a preferred embodiment, the ends of the measuring arms which are at the front in the insertion direction of the slide can be spaced apart from one another transversely to the insertion direction in the direction of the normal force. The spacing makes it possible to insert the slide between the two measuring arms without great effort. With a plane-parallel arrangement of the measuring arms, a measuring arm can simulate an upper or lower section of an electrical contact. As a result, the measuring arms can absorb the normal force which acts perpendicularly on the outer surface facing away from the opposite measuring arm. The normal force that acts on one measuring arm is opposite to the normal force that acts on the other measuring arm. The measuring arms can preferably be mirror-symmetrical to one another.

According to a further advantageous embodiment, the measuring instrument can have at least four measuring arms, wherein adjacent measuring arms are arranged at a substantially right angle and the opposing measuring arms are arranged parallel to one another in order to simulate an electrical contact with a rectangular cross section.

According to a further advantageous embodiment, the measuring instrument can have a plurality of circular segment-shaped measuring arms which lie next to one another and result in a closed circular cross section. As a result, depending on the distribution of the contact points of the plug, all contact points can be measured transversely to the plugging direction during a measurement process.

According to a further advantageous embodiment, at least two measuring arms can, if one is not inserted between the measuring arms Sliders can be deflected in the direction of one another. This prevents a large frictional force from occurring between the contact points of the connector and the measuring arms when it is inserted into the connector. The measuring arms can be reinforced by the slide and the deflection of the measuring arms in the direction of one another can be blocked so that the normal force that would act on an electrical contact can be measured.

According to a further advantageous embodiment, the measuring arms can be deflected apart by the inserted slide. This increases the height in the direction of the normal force and the contact points can be contacted. Both measuring arms can preferably be deflected uniformly. The height of the measuring section, which is formed by the measuring arms inserted into the connector, in the direction of the normal force, can correspond to the height of an electrical contact of a mating connector in the direction of the normal force.

In an embodiment in which the measuring arms are not inserted centrally into the connector in the direction of the normal force, one measuring arm can be deflected more than the other measuring arm.

In order to measure a normal force at a plurality of contact points at the same time, the at least one normal force sensor can have a plurality of measuring cells or a plurality of normal force sensors can be arranged at different points of at least one measuring arm.

According to an advantageous embodiment, all measuring arms can be provided with at least one normal force sensor. As a result, the normal force at the contact points can be absorbed by the respective measuring arms.

The measuring arms can be pretensioned in the direction of one another, so that the measuring arms lie against one another at least in sections when the slide is not inserted. The free ends of the measuring arms lying at the rear in the insertion direction of the slide preferably lie against one another. As a result, the measuring instrument has a small height perpendicular to the insertion direction on the measuring arms lying against one another, which is only formed by the material thickness of the measuring arms. The free ends of the measuring arms can thus be inserted into the plug in a plug-in direction without contacting the contact points of the plug to be tested.

The material thickness of the slide in the direction of the normal force can, at least in sections, be greater than the clear width between the measuring arms. As a result, the measuring arms can be deflected away from one another in the direction of the normal force by the slide during insertion in an insertion direction between the measuring arms.

The slide can have a round, rectangular, square, or elliptical cross section so that the cross section of the electrical contact can be simulated. The slide can preferably have the same mechanical properties as the electrical contact, so that the result of the measurement can be precisely transferred to an electrical contact.

According to a further advantageous embodiment, the arrangement and number of normal force sensors or measuring cells of a normal force sensor on the measuring arm can correspond at least to the arrangement and number of contact points on which normal forces act from the plug. Plugs can exert normal forces on several contact points from an electrical contact of a mating plug. The normal force can be different at each contact point. It is therefore desirable to determine the normal forces from each contact point in a single test. In particular, the number of contact points at which the normal force is measured can be greater than two.

Since the insertion track is avoided in the measuring instrument according to the invention, at least one one-way normal force sensor can be used according to an advantageous embodiment. The at least one single-use normal force sensor can be arranged on at least one measuring arm before the measuring process and removed after the measuring process. A one-way normal force sensor can, for example, be a permanently optically and / or plastically changeable sensor.

In order to keep the costs of the measuring instrument low, the normal force sensor can be a pressure- or force-sensitive film that can be optically changed by the normal force. The pressure- or force-sensitive film can be attached before the measurement and can be removed for evaluation after the measurement. A purely optically changeable pressure or force sensitive film means that no electrical sensors, such as piezoelectric sensors, which increase the manufacturing costs of a measuring instrument, have to be used. Especially with a large number of contact points, the use of electrical sensors leads to high production costs, since a measuring cell or a normal force sensor is necessary for each contact point. Furthermore, the integration density of piezoelectric and piezoresistive sensors with local discrimination is technically limited, which results in blind areas. This is not possible with pressure- or force-sensitive foils. A measurement with a pressure- or force-sensitive film can be carried out independently of the slide.

According to an advantageous embodiment, the optical change in the at least one normal force sensor can be evaluated by a program after the measuring process. Alternatively or additionally, the optical change in the normal force sensor can be evaluated manually by a user.

In a further embodiment, the at least one normal force sensor can be plastically deformable by the normal force. This results in a three-dimensional print that can be evaluated by an optical or a tactile device, such as a 3D microscope or a surface profilometer.

According to a further advantageous embodiment, the at least one normal force sensor can be discolored by the normal force. The intensity of the discoloration can be proportional to the applied force or pressure and is therefore representative of the normal force. The normal force sensor can preferably be a film. The advantage of a film that can be discolored by normal force is, in addition to the low price compared to a piezoelectric or piezoresistive sensor, that a high spatial resolution is achieved. Furthermore, the foils can be cut to any size and shape, depending on the application, which enables the uncomplicated production of measuring instruments with different dimensions for different types of connectors.

A film that changes color can be single-layer or double-layer. The measuring film can be provided with micro color capsules and a developer layer. When the normal force is applied, the first micro-color capsules burst and the developer layer changes color slightly. If the load increases further, more and more micro color capsules burst, so that the intensity of the discoloration increases. The discoloration can preferably be permanent. The developer layer thus produces a document-safe printed image in which the intensity of the discoloration is a measure of the normal force.

Connectors, such as the commercially available connectors MCON 8, MCON 9.5, MCON 12, PCON 12 and PCON 21 from TE Connectivity, have more than four contact points at which a normal force acts on the contact points of an electrical contact from a mating connector. The normal forces can be different at each contact point. In order to measure several or all contact points of a plug in a single measuring process, a normal force sensor with a high local resolution is necessary. Piezoelectric and piezoresistive normal force sensors do not have a sufficiently high spatial resolution. It is therefore necessary to carry out several plug-in processes or to carry out measurements on several connectors of the same type in order to measure the normal force at all contact points, whereby it must be assumed that the different connectors of the same type are of the same quality. In the case of high-current contacts with more than 100 contact points, these methods are not sufficient from a quality assurance perspective.

With an optically active normal force sensor, a high spatial resolution of around 64 contact points or more can be achieved on an area of only 1 mm ² . Therefore, when using an optically active normal force sensor, all contact points of microscopic size, on each of which a normal force acts, can be examined simultaneously with a single measurement process.

The measuring instrument can have a holder for attaching the measuring arms, the measuring arms extending away from the holder. This prevents the measuring arms from slipping and being unevenly inserted into the connector. The holder can preload the measuring arms towards one another so that at least the free ends of the measuring arms lying at the rear in the insertion direction of the slide rest against one another. The measuring arms can preferably extend away from the holder in the insertion direction.

The holder can be formed from two blocks, between which the measuring arms are fastened at least in sections. The two blocks can be made of aluminum and connected to one another by fastening bolts. This prevents the connection between the blocks from loosening easily and the measuring arms attached to them from slipping.

The holder can have a guide for guiding the slide. The guide can extend along the insertion direction and pass through the holder in the insertion direction. The measuring arms can extend away from the holder in the rear end of the guide in the insertion direction of the slide.

The measuring instrument can have at least one spacer block, on each of which a measuring arm is arranged on the outer surfaces perpendicular to the insertion direction. As a result, the measuring arms are spaced from one another and allow the slide to enter between the measuring arms without great effort. The measuring instrument can preferably have two spacer blocks spaced apart in a direction transverse to the insertion direction so that the gap between the spacer blocks can act as a guide for the slide.

The at least one spacer block can be made from sheet metal and fastened in the holder, a measuring arm in each case being arranged between an outer surface of the spacer block and a block from the holder.

The measuring arms can have a fastening section which is widened transversely to the insertion direction and can be penetrated with at least one fastening opening transversely to the insertion direction and parallel to the normal force direction. The at least one spacer block and the holder can also have at least one fastening opening penetrated, so that the at least one fastening opening of the holder, the spacer block and the measuring arms are aligned with one another. This enables the spacer block and the measuring arms to be easily fastened between the blocks of the holder, for example by means of a screw connection.

A run-on bevel, for example in the form of a bevel, can be formed by the free end of the slide at the rear in the insertion direction. This makes it easier to insert the slide between the measuring arms and prevents excessive abrasion of the slide and the measuring arms.

At the front free end of the slide in the insertion direction, a handle section can be arranged in order to facilitate the handling of the slide for the user. The grip section can be widened transversely to the insertion direction. In particular, the handle section can be wider than the guide of the slide transversely to the direction of insertion. This prevents the slide from being inserted too deeply between the measuring arms, since the grip section strikes against a wall of the guide.

The measuring instrument can have at least one clamping plate which clamps at least one end of the at least one normal force sensor between at least one measuring arm and the clamping plate. This enables the normal force sensor to be easily clamped and removed before and after the measuring instrument is plugged into the plug to be tested. The measuring instrument can preferably have two clamping plates which each rest on a measuring arm on the outer surface facing away from the opposite measuring arm. The at least one normal force sensor can be clamped with a slight play between the clamping area and the measuring arm so that the normal force sensor is not damaged when the slide is inserted and the forces for inserting the slide do not become too high. Alternatively or additionally, the normal force sensor can be clamped movably in the plugging direction between the clamping plate and the measuring arm. As a result, when the slide is inserted, there is no overvoltage or damage to the normal force sensor.

The measuring arms can be prestressed in the direction of one another by the at least one clamping plate. For this purpose, the clamping plate can have a clamping section which is bent in the direction of the measuring arm and which exerts a force parallel to the normal force on the measuring arm. The normal force sensor can be at least partially clamped between the clamping section and the outer surface of the measuring arm facing away from the opposite measuring arm. The normal force sensor can preferably be clamped in with a free end.

The at least one clamping plate can be fastened in the holder and extend away from the holder in the insertion direction of the slide. The at least one clamping plate can be fastened between the measuring arm and the block of the holder.

The at least one clamping plate cannot extend as far away from the holder as the measuring arms. The clamping plate can preferably form a stop which strikes the plug when it is inserted. Alternatively or additionally, at least one measuring arm can have a stop for blocking the plugging movement and the clamping plate can end in front of the stop in the plugging direction. It can thus be prevented that the at least one clamping plate is plugged into the plug.

The measuring instrument can have at least one stop against which the plug strikes when it is inserted, in order to prevent the measuring instrument from being inserted too deeply into the plug. The stop can be, for example, an arm of the bracket that protrudes in the plugging direction.

According to an advantageous embodiment, the measuring instrument can have at least one stop for positioning the at least one normal force sensor. This ensures that the at least one normal force sensor is correctly arranged on the measuring arm. Furthermore, in the case of several measurements, errors due to different arrangements of the at least one normal force sensor on the measuring arm can be avoided and reproducible and comparable measurement results can thus be determined.

The at least one stop can be formed by at least one shoulder of the measuring arms that protrudes in the insertion direction, as a result of which the mobility of the normal force sensor is locked transversely to the insertion direction. Since the shoulder extends in the direction of insertion, the height of the measuring arm is not increased unnecessarily in the direction of the normal force.

According to an advantageous embodiment, the at least one stop on at least one Be arranged clamping plate. The at least one stop can be shaped as a shoulder that prevents the normal force sensor from slipping transversely to the direction of insertion.

The at least one normal force sensor can completely cover the measuring arms at least in a measuring area that is plugged into the plug. As a result, all forces that act on the at least one normal force sensor can be absorbed by the at least one normal force sensor.

The at least one normal force sensor can be a film which can be clamped in a clamping area in the insertion direction around the measuring arms in a second clamping area. As a result, the film is clamped on the outer surface facing away from the opposite measuring arm and comes into direct contact with the contact points of the plug to be tested. Since the at least one normal force sensor is clamped in by a clamping area outside the section that is plugged into the plug, the measurement results are not falsified by the force acting on the at least one normal force sensor in the clamping area.

The measuring instrument can have a large number of slides with different material thicknesses, so that the nominal thickness of the contact as well as the upper and lower thickness tolerance can be examined by the selection of the slide.

Furthermore, when measuring the normal force with different material thicknesses, a spring characteristic can be determined. Furthermore, a situation can be checked in which there is guaranteed no plastic deformation of the contact springs of the connector. In such a case, despite the examination with the measuring instrument according to the invention, the plugs are still unmated new parts, since the coatings of the contact points of the plug are not changed either.

The measuring arms, the at least one clamping plate, the slide and the at least one spacer block can be formed from sheet steel. This enables simple and inexpensive production of the measuring instrument, for example by punching.

The measuring instrument can have a fixation for fixing the holder. This can, for example, be a base plate with receptacles for plug-in pins of the holder. This prevents slipping during insertion into the connector and increases the reproducibility of the results.

The fixation can ensure that the measuring arm can be inserted into the plug without contacting the plug, thus avoiding incorrect connection. The fixation can also include a holder for the plug, a center line of the plug in its receptacle in the direction of the normal force being aligned with the center line between the two measuring arms. The holders of the plug and the measuring instrument can be movable towards one another. The connector holder can be detachable from the fixation and can be moved relative to the fixation. The fixation can have a guide for precise movement of the connector holder and holder with respect to one another. The guide can ensure that the center line in the horizontal direction of the receptacle of the plug is aligned with the center line of the measuring arms in the horizontal direction transversely to the plug-in direction. This ensures that the measuring instrument can be plugged into the plug uniformly and precisely with its measuring section.

According to an advantageous embodiment, the fixation can have a plurality of holders arranged next to one another, in particular parallel to the plug-in direction. The connector holder can also have a plurality of connector receptacles lying next to one another, in particular arranged parallel to the plug-in direction. This means that several connectors can be tested at the same time. The connector holder can be provided with at least one handle in order to ensure uniform movement of the connector receptacles. The at least one handle can be arranged between two connector receptacles lying next to one another.

The slide can have a drive with which it can be inserted or pulled out between the measuring arms. The drive can be operated hydraulically, pneumatically, electrically or mechanically. This enables an automatic measurement with a preset measurement duration to be achieved. Furthermore, the slide can be coupled to an eccentric with which the slide can be pushed in and / or pulled out between the measuring arms by rotating the eccentric.

According to a further advantageous embodiment, the measuring instrument can have two slides, the insertion direction of one slider running parallel to the insertion direction and the insertion direction of the other slider running anti-parallel to the insertion direction. The measuring arms can extend from a holder to a holder opposite in the plug-in direction and be fastened in these holders.

By inserting slides in the plugging direction and against the plugging direction, several can be connected to each other in the plugging direction spaced contact points at the same time the maximum force can be achieved.

The slide can end with a taper, in particular a tip, in the insertion direction. The taper can extend in the insertion direction according to the distance between the contact points. As a result, contact points located at the rear in the insertion direction and the contact points arranged further forward in the insertion direction can be simultaneously lifted and pressed against the contact points of the plug with maximum force. The contact points of the plug can be coupled to one another, so an uneven contact would lead to an error in the measurement, since with an uneven contact higher normal forces can be measured compared to the actual application.

According to an advantageous embodiment, the method can include the clamping of at least one normal force sensor on at least one measuring arm. The at least one normal force sensor can be a film for a single measurement and can be stretched on the measuring arms before the measuring arms are inserted into the plug and removed from the measuring arms after the measuring arms have been pulled out of the plug. The normal force sensor can preferably be a force- and / or pressure-sensitive film, which is optically changeable, in particular discolored, in proportion to the force or pressure acting. In this way, a high spatial resolution can be achieved with which the normal forces that act on all contact points can be measured in a single measurement process.

In previous methods, one to two normal force values are usually recorded per measurement. In previous methods, due to the limited spatial resolution, the normal force is measured summed over several contact points. In order to cover all areas with contact points, measurements are made on several plugs, whereby it must be assumed that these are of the same quality. In the case of high-current contacts with more than 100 contact points, these methods are not sufficient from a quality assurance perspective. Since no plug-in track is recorded in the measuring instrument, an optically changeable film can be used as a normal force sensor and the normal forces that act on all contact points can be measured simultaneously in one measuring process.

According to an advantageous embodiment, the measuring instrument can have at least one stop and the measuring arms can be inserted into the plug until the stop strikes the plug. The thickness in the direction of the normal force of the measuring section inserted into the connector can preferably be significantly less than the thickness in the direction of the electrical contact of the mating connector.

In a further advantageous embodiment, the slide can have at least one stop and the slide can be inserted between the measuring arms until the stop strikes against an element of the measuring instrument. The measuring section can imitate the thickness of the electrical contact or the upper or lower tolerance limit in order to carry out an accurate measurement that is representative of the electrical contact.

In particular, the normal force at a large number of contact points, in particular more than four contact points, can be measured at the same time during a measurement process. The normal force can be measured at e.g. but not exclusively over 100 contact points. The contact points can be examined in a microscopic size, approximately 0.1 mm, in one measuring process.

The measurement of the normal force can take about 5 s to about 15 s. This measures a static load that is representative of the static load that would act on an electrical contact of a mating connector. If the parameters temperature, humidity, exposure time and development time are taken into account when evaluating the discolored areas, significantly shorter and significantly longer exposure times are also possible, e.g. 0.1 s or 2 min.

After measuring the normal force at at least one contact point of a measuring arm provided with a normal force sensor, the slide can be pulled out between the measuring arms. As a result, the measuring arms can be biased towards each other again and the contact points of the measuring arms no longer contact the contact points of the plug.

The measuring arms can be pulled out of the plug after pulling out the slide. As a result, there is no insertion track on the at least one normal force sensor when it is pulled out.

After the measuring arms have been pulled out of the plug, the at least one normal force sensor can be removed and evaluated. In particular, it is possible to wait about 30 minutes before the evaluation in order to ensure a sufficiently long development time for the normal force sensor. If the parameters temperature, humidity, exposure time and development time are taken into account when evaluating the discolored areas, significantly shorter and significantly longer development times are also possible, e.g. 10 s or 48 hours.

According to a further advantageous embodiment, the at least one normal force sensor can be removed after the measuring arms have been pulled out of the plug in order to replace the at least one normal force sensor.

In the following, the invention is explained in more detail by way of example on the basis of advantageous configurations with reference to the drawings. The advantageous further developments and refinements shown here are in each case independent of one another and can be combined with one another as required, depending on how this is necessary in the application.

• 1 eine schematische Perspektivansicht eines erfindungsgemäßen Messinstruments mit einem eingeführten Schieber;
• 2 eine schematische Schnittansicht eines erfindungsgemäßen Messinstruments mit einem eingeführten Schieber;
• 3 eine schematische Perspektivansicht eines Messarmes von einem erfindungsgemäßen Messinstrument;
• 4 eine schematische Perspektivansicht eines Klemmblechs von einem erfindungsgemäßen Messinstrument;
• 5 eine schematische Perspektivansicht eines weiteren erfindungsgemäßen Messinstruments;
• 6 eine schematische Schnittansicht eines elektrischen Kontakts in einem Stecker;
• 7 eine schematische Schnittansicht eines erfindungsgemäßen Messinstruments in einem Stecker mit mehreren Kontaktstellen; und
• 8 eine schematische Schnittansicht eines erfindungsgemäßen Messinstruments in einem Stecker mit mehreren Kontaktstellen und einem eingeführten Schieber

Show it,

• 1 a schematic perspective view of a measuring instrument according to the invention with an inserted slide;
• 2 a schematic sectional view of a measuring instrument according to the invention with an inserted slide;
• 3 a schematic perspective view of a measuring arm of a measuring instrument according to the invention;
• 4th a schematic perspective view of a clamping plate of a measuring instrument according to the invention;
• 5 a schematic perspective view of a further measuring instrument according to the invention;
• 6th a schematic sectional view of an electrical contact in a plug;
• 7th a schematic sectional view of a measuring instrument according to the invention in a plug with several contact points; and
• 8th a schematic sectional view of a measuring instrument according to the invention in a plug with several contact points and an inserted slide

In 1 is a measuring instrument according to the invention 1 in a schematic perspective view and in 2 shown in a schematic sectional view.

For easier orientation, a Cartesian coordinate system is used in the description with a height direction z , a longitudinal direction x and a transverse direction y , where the longitudinal direction x essentially parallel to an insertion direction E. is.

The measuring instrument comprises two measuring arms 2 , a slider 4th , two clamping plates 6th , two spacer blocks 8th , a bracket 10 and a normal force sensor 12th . One plug 13th is in 1 indicated schematically with a dashed line.

The bracket 10 has an upper block 14th and a lower block 14 ' on. The blocks 14th and 14 ' are with mounting holes 16 provided, with the upper and lower block 14th , 14 ' with the mounting holes 16 in height direction z are interspersed. The blocks 14th , 14 ' have a cuboid base body and extend along a longitudinal axis L. that are essentially parallel to the longitudinal direction x runs. The blocks 14th , 14 ' are each symmetrical to the longitudinal axis L. built up. The longitudinal axis L. forms an axis of symmetry 18th , on the side flanks 20th , 20 'of the respective blocks 14th , 14 ' are mirror symmetrical to each other.

Three at a time along the length x spaced apart fastening openings 16 are on the side flanks 20th , 20 'arranged. The lengthways x on the side flanks 20th , 20 'arranged central fastening openings 22nd of the upper block 14th each have a conical depression 24 on that of the lower block 14 ' facing away from surface 26th on, in which a shoulder of a fastening bolt can be received (not shown).

With the help of fastening bolts (not shown) the upper block 14th and the lower block 14 ' are pressed together so that the in the holder 10 elements located are immovably attached. The fastening bolt can be attached to the lower bolt 14 ' from the mounting hole 16 at the one from the upper block 14th protrude away from the side and be fastened in a receptacle of a fixation (not shown). As a result, the holder can be arranged in a rigid manner on a fixation, which simplifies the reproducibility of measurement results and prevents incorrect insertion. The blocks 14th , 14 ' can be formed from aluminum.

The measuring arms 2 , 2 ' , Clamping plates 6th , 6 ' , Spacer blocks 8th , 8th' are between the upper block 14th and the lower block 14 ' in the holder 10 trapped.

The measuring arms 2 , 2 ' and clamping plates 6th , 6 ' each have a fastening section for this purpose 27 on, which is analogous to the one on the opposite block 14th , 14 ' turned faces of the blocks 14th , 14 ' is constructed so that the mounting holes 16 the blocks and the mounting holes 16 the measuring arms 2 , 2 ' and clamping plates 6th , 6 ' align with each other.

The spacer blocks 8th , 8th' are in height direction z between the blocks 14th , 14 ' arranged and also have fastening openings 16 on that with the mounting holes 16 the other elements of the bracket 10 cursing. The spacer blocks 8th , 8th' are in the transverse direction y spaced from each other. An emerging gap 28 that are in the transverse direction y extends between the spacer blocks, penetrates the bracket 10 along the longitudinal axis L. . The clear width 30th the gap 28 between the spacer blocks 8th '8' roughly corresponds to a clear width 31 an insertion section 32 of the slide 4th . The material thickness of the spacer blocks 8th , 8th' in height direction z corresponds roughly to the material thickness of the slide 4th in height direction z . This allows the slide 4th easy and without great effort in the direction of insertion E. in the holder 10 inserted or against the direction of insertion E. be pulled out. The gap 28 serves as a guide here 33 for the slider 4th .

The measuring arms 2 , 2 ' are each at one in height direction z spaced apart side of the spacer blocks 8th , 8th' arranged so that the measuring arm 2 between the upper block 14th and the spacer blocks 8th , 8th' and the measuring arm 2 ' between the lower block 14 ' and the spacer blocks 8th , 8th' are arranged. This makes the measuring arms 2 , 2 ' at their attachment sections 27 in the direction transverse to the insertion direction E. spaced apart and the slide 4th can simply be placed between the measuring arms 2 , 2 ' to be introduced.

Between the measuring arms 2 , 2 ' and the upper block 14th or the lower block 14th are the clamping plates 6th or. 6 ' arranged so that the clamping plates 6th , 6 ' on one of the measuring arms 2 , 2 ' facing away from the outer surface 34 the measuring arms 2 , 2 ' are arranged.

This results in a stack structure 36 of the measuring instrument 1 , where in height direction z the lower block 14 ' , the clamping plate 6 ' , the measuring arm 2 ' who have favourited spacer blocks 8th , 8th' , the measuring arm 2 , the clamping plate 6th and the upper block 14th successive.

The measuring arms 2 , 2 ' , Clamping plates 6th , 6 ' , Spacer blocks 8th , 8th' and the slide 4th can be formed from sheet steel. This enables simple and inexpensive production of the elements, for example by punching.

The structure of a measuring arm according to the invention 2 , 2 ' of the measuring instrument according to the invention 1 , this in 1 is shown in 3 shown. The measuring arm 2 , 2 ' is with its fastening section 27 can be fastened in the holder. The fastening section 27 has the same shape as that of the opposite block 14th , 14 ' pointing face of a block 14th , 14 ' so that the mounting holes 16 of the fastening section 27 and the blocks 14th , 14 ' align with each other. The measuring arm 2 , 2 ' extends in the longitudinal direction x from the attachment portion 27 path. The width narrows in the transverse direction y gradually in two stages 38 , 40 up to the clear width 32 in the transverse direction y of the slide 4th .

Due to the stepped transition from the first step 38 to the second stage 42 one forms in the transverse direction y extending shoulder 42 . The shoulder 42 serves as a stop 44 , to which a plug is plugged in in one direction S. that are essentially parallel to the direction of insertion E. runs, strikes. This prevents the measuring arm 2 , 2 ' can be inserted too deeply into the connector.

The second stage 40 forms a measuring section 46 that can be plugged into a plug. The measurement section 46 has one in the transverse direction y running clear width 48 on, which is essentially the clear width in the transverse direction y corresponds to a mating connector that is compatible with the connector.

This in 1 illustrated measuring instrument 1 and the in 3 illustrated measuring arm 2 , 2 ' are dimensioned for the measurement of a normal force of a PCON 21 connector. Depending on requirements, the structure and dimensions of one of the components of the measuring instrument 1 or all of the components differ from the configuration shown.

On one lengthways x rear free end 50 of the measuring section 46 extend in the longitudinal direction x two positioning stops 52 that crosswise y are spaced from each other. The positioning stops 52 allow an exact attachment of a normal force sensor 12th on the measuring arm 2 , 2 ' without slipping in the transverse direction y . The material thickness in the height direction z a measuring arm 2 , 2 ' corresponds to 0.1 mm in this exemplary embodiment.

The clamping plate 6th , 6 ' is in 4th shown in a schematic perspective view. The clamping plate 6th , 6 ' points analogously to the measuring arm 2 , 2 ' an attachment portion 27 on, its fastening openings 16 the fastening section 24 in height direction z enforce and with the fastening openings 16 of the holder 10 cursing.

The clamping plate 6th , 6 ' extends in the longitudinal direction x from the fastening section 27 with a substantially U-shaped cross-section 54 away, with the arms 56 of the U-shaped cross-section 54 in the transverse direction y , and the trunk 58 holding both arms 56 connects to each other, lengthways x extend. Between the arms 56 is a window 60 that in one in the holder 10 fastened state (see 1 ) an access or a look at the first level 38 of the measuring arm 2 , 2 ' allowed.

The strain 58 is towards the measuring arm 2 , 2 ' bent so that of the fastening section 27 longitudinal x distant arm 56 a clamping area 61 forms on the measuring arm 2 , 2 ' strikes. Through the clamping area 61 a clamping force acts 62 essentially anti-parallel or parallel to the height direction z on the measuring arm 2 , 2 ' . This will make the measuring arms 2 , 2 ' biased towards each other. From that of the bracket 10 facing arm 56 of the clamping plate 6th , 6 ' two positioning stops extend 63 longitudinal x in the window 60 into it. The positioning stops 63 are in the transverse direction y from each other with the clear width 48 of the measuring section 46 spaced.

A normal force sensor 12th in the form of a film is in the clamping area 61 between arm 56 and measuring arm 2 trapped. The normal force sensor extends in the longitudinal direction x over the measuring section 46 of the measuring arm 2 away and is around the free ends 50 the measuring arms 2 , 2 ' bent back so that the slide 64 along the longitudinal axis L. extends on the measuring arm 21 and in the clamping area 61 between arm 56 and measuring arm 2 ' is jammed. Thus, the normal force sensor 12th a substantially U-shaped cross-section. This means that the normal force sensor is around the measuring section 46 the measuring arms 2 , 2 ' stretched and can the contact points of a plug 13th to contact.

The normal force sensor 12th is around the free ends 50 the measuring arms 2 , 2 ' bent back. The normal force sensor 12th a constriction 68 so that the normal force sensor 12th in the transverse direction y at the positioning stops 52 can strike and the position of the normal force sensor 12th at the free end 50 is determined and reproducible.

The normal force sensor 12th protrudes into the window 63 inside and is between the positioning stops 63 of the clamping plate 6th , 6 ' positioned. Thus is the position of the normal force sensor 12th on the measuring arms 2 , 2 ' precisely determined and can be reproduced for different measurements.

The clear width 66 of the normal force sensor 12th in the transverse direction y corresponds to the clear width 48 of the measuring section 46 , hence the measurement section 46 completely covered with the normal force sensor. This ensures that all contact points of the plug 13th , where there is a normal force on the measuring section 46 acts, from the normal force sensor 12th to be contacted.

In the case of a slider that has not been inserted 4th can the measuring arms 2 , 2 ' at least in the measurement section 46 lie against each other. As a result, the measuring instrument 1 in the measuring section 46 a small height in the vertical direction z on, and can without contacting the plug 13th in the connector 13th be inserted. When plugging in with a small height of the measuring section 46 in height direction z in the connector 13th wear out the contact points of the plug 13th not and show no signs of use. Furthermore, a plug-in lane is not used by the normal force sensor 12th recorded, whereby an accurate measurement with an optically changeable normal force sensor 12th is possible.

With a PCON 21 connector, a measuring arm 2 , 2` 14 contact points each contacted, each contact point being formed by a further eight microscopic contact points. This means that a very high spatial resolution is necessary, with a piezoelectric or piezoresistive normal force sensor 12th cannot be achieved. With an optically changeable normal force sensor, a high spatial resolution can be achieved, eg 64 contact points per mm ² or more and the normal force can be differentiated at all 112 contact points of the PCON 21 connector.

The normal force sensor 12th In this exemplary embodiment, it has a material thickness in the height direction z of about 90 ± 5 µm. Thus, the measuring section 46 in the case of a slider that has not been inserted 4th a total material thickness in the height direction z of about 0.38 ± 0.01 mm.

The lead-in section 32 extends in the longitudinal direction x of one in the direction of insertion E. forward end 70 the leadership 33 to about the free end 50 the measuring arms 2 , 2 ' or ends shortly before it and has a constant clear width 31 on, which is roughly the clear width 48 the measuring arms 2 , 2 ' and also the leadership 33 corresponds or is smaller by a small tolerance, so that simple, smooth and straight insertion without possible deflection in the transverse direction y of the slide 4th is possible. To operate the slide 4th indicates the slide 4th one symmetrical to the longitudinal axis L. widespread grip surface 72 on that opposite to the direction of insertion E. to the lead-in section 32 connects. By widening the slide 4th extends in or against the transverse direction y a locking shoulder 74 that when the insertion section is fully inserted 32 at the in the direction of insertion E. front side of the bracket 10 strikes and thus inserting the slide too far 4th prevented.

From one lengthways x rear end 76 is a lengthways x tapered tip 77 shaped. This allows the Measuring arms 2 , 2 ' light and even in height direction z be deflected away from each other.

The material thickness in the height direction z of the slide 4th corresponds roughly to the material thickness in the height direction z the spacer blocks 8th , 8th' or is lower by a small tolerance. This allows the slide 4th easily into the lead 33 are introduced and a pivoting in the vertical direction z will be prevented. A swiveling out in the vertical direction z of the slide 4th would result in an uneven deflection of the measuring arms 2 , 2 ' result, whereby the measurement results are falsified.

Depending on the test conditions, the material thicknesses can vary in height z of the slide 4th and the spacer blocks 8th , 8th' can be varied. In this exemplary embodiment, the material thickness corresponds to approximately 2.4 mm, which increases the height of the measuring section 46 to about 2.78 ± 0.01 mm with an inserted slider 4th elevated. With this height, an electrical contact of a mating connector that is compatible with the connector is simulated and the normal force that acts on the electrical contact of the mating connector can be measured.

For the process it is advantageous to use the stack structure 36 as the first step to build. The normal force sensor 12th will be on the measuring arms 2 , 2 ' positioned so that the measuring range 46 on that of the opposite measuring arm 2 , 2 ' facing away from the outer surface 34 complete with the normal force sensor 12th is covered. In the exemplary embodiment, the holder 10 be fixed on a fixation.

To clarify the principle of the measuring instrument 1 is in 6th an electrical contact 78 in the form of a contact pin in a plug 13th in the form of a socket contact shown schematically in a sectional view.

The contact 78 is in the mating direction S. in the connector 13th plugged in. The plug 13th has two contact springs 79 perpendicular to the mating direction S. on that at multiple contact points 80 against contact points 81 of the contact 94 with a normal force N press. The contact 78 has a height H ₂ on that of the measuring section 46 with the slider inserted 4th is achieved. The normal force N can at the various contact points 81 be different levels. The measuring instrument 1 imitated when the slider is inserted 4th at least in the introduced measuring section 46 the inserted contact 94 of the mating connector and thus also has the contact points 81 on that of the contact springs 79 can be contacted.

One in one plug 13th introduced measuring section 46 is in 7th shown schematically. The plug 13th has multiple contact points 80 (A, B, C, D, F, G) at which a normal force when a mating connector is inserted N on the electrical contact 78 of the mating connector works.

The one with the normal force sensor 12th provided measuring arms 2 , 2 ' show analogous to the connector 13th Contact points 81 on that with an inserted slide 4th one contact point each 80 of the plug 13th to contact.

The measuring arms 2 , 2 ' lie in the measuring section 46 to each other and have a height H ₁ in height direction z on. The height H ₁ in the measuring section 46 is made up of the material thicknesses of the measuring arms 2 , 2 ' and twice the material thickness of the normal force sensor in the height direction z together. Because the height H ₁ is much less than the height of the electrical contact 78 from one to the connector 13th compatible mating connector, the contact points are 80 from the contact points 81 the measuring arms 2 , 2 ' not contacted. Therefore, it shows by plugging in the measuring section 46 no mating track on the normal force sensor 12th . It also prevents the contact points 80 show signs of wear due to plugging.

After the measurement section 46 completely into the plug 13th is inserted, the slider will 4th in the direction of insertion E. between the measuring arms 2 , 2 ' introduced.

8th shows one in a plug 13th inserted measuring section 46 with an inserted slide 4th . Through the slider 4th become the measuring arms 2 , 2 ' evenly in height direction z distracted. Thus, at least the measuring section 46 a height H ₂ on, which is roughly the level of the electrical contact 78 of the mating connector. This makes contact with the measuring arms 2 , 2 ' with their contact points 81 the contact points 80 of the plug 13th . It works at every contact point 81 (A, B, C, D, F, G) a normal force N (N _A , N _B , N _C , N _D , N _F , N _G ) in each contact point 81 can be different. The normal force N is by the normal force sensor 12th recorded. Preferably the slide remains 4th introduced for about 5 to 15 s so that the normal forces N about 5 to 15 s on the normal force sensor 12th can act.

After the measurement has been made, the slider will 4th against the direction of insertion E. pulled out. The measuring arms 2 , 2 ' because of their mechanical pre-tensioning, the in 5 is reached. Thus, the measuring instrument can 1 against the direction of insertion S. from the plug 13th be unplugged without the contact points 80 of the plug 13th to contact.

After unplugging the normal force sensor 12th removed and a new normal force sensor attached for a next measurement. In order to ensure a sufficiently long development time for the color intensity, you have to wait about half an hour before evaluating the measurement results. The normal force sensor 12th can be scanned and evaluated with a program that determines the color intensity of a measuring cell of the normal force sensor 12th into the normal force acting on this measuring cell N converts. Alternatively, the results can be evaluated manually by a user.

In 5 is a further embodiment according to the invention of a measuring instrument with a fixation 84 shown.

The fixation 84 is a flat plate that is perpendicular to the direction of insertion S. with fixation openings 86 is provided. On the fixation 84 are two parallel to the longitudinal direction x arranged in the transverse direction y spaced apart brackets 10 with fastening bolts 88 attached. The fastening openings are aligned 16 each with a fixation opening 86 .

There is also a connector holder 90 to see the relative to the mounts 10 is free to move in any direction. The connector holder 90 has a collar 92 on the the connector bracket 90 transverse to the mating direction S. circled. The connector holder 90 is with two connector receptacles arranged parallel to one another 94 interspersed with one connector each 13th against the direction of insertion S. can be introduced. Furthermore, the connector holder 90 a handle 96 on, the one in the mating direction S. from the connector bracket 90 protrudes and for evenly guiding the connector holder 90 serves. The handle 96 is between the connector receptacles arranged parallel to one another 94 positioned so that movement occurs smoothly and there is no deflection of one side of the connector bracket 90 comes.

The plug 13th can be opposite to the plugging direction S. into the connector holder 90 to be introduced.

Through the collar 92 can the connector bracket 90 be placed on the fixation, and the center line in height direction z aligns with the center line between the measuring arms 2 , 2 ' so that the measuring arms 2 , 2 ' simply and precisely into the connector 13th can be plugged in. The connector holder 90 is in 5 to the mating direction S. shown rotated to the connector receptacle 92 to show.

A guide on the fixation is not shown 84 into which the connector holder 90 can be used and which is in the direction of the bracket 10 extends. With a guide it can be ensured that the center line in the transverse direction y the receptacle of the plug 13th with the center line in the transverse direction y the measuring arms 2 , 2 ' aligns and the measuring arms 2 , 2 ' precisely in the connector 13th can be plugged in.

The plug receptacles 92 are in the transverse direction y spaced from each other so that each has a center line in the transverse direction y a receptacle of a plug 13th with a center line in the transverse direction y the one in a holder 10 attached measuring arms 2 , 2 ' is aligned and two plugs can be tested at the same time.

The bracket 10 and the connector bracket 90 are movable to each other, so that the measuring section 46 in the mating direction S. in the connector 13th can be introduced.

List of reference symbols

1

Measuring instrument

2, 2 '

Measuring arms

4th

Slider

6, 6 '

Clamping plate

8, 8 '

Spacer block

10

bracket

12th

Normal force sensor

13th

plug

14, 14 '

upper block, lower block

16

Mounting hole

18th

Axis of symmetry

20th

Side flanks

22nd

middle mounting holes

24

Lowering

26th

averted area

27

Fastening section

28

gap

30th

clear width between the spacer blocks

31

clear width of the insertion section

32

Lead-in section

33

guide

34

Exterior surface

36

Stacking

38

first stage

40

second step

42

shoulder

44

attack

46

Measuring section

48

clear width of the measuring section

50

free end

52

Positioning stop

54

U-shaped cross-section

56

poor

58

tribe

60

window

61

Clamping area

62

Clamping force

63

Positioning stops

64

foil

66

inside width of the normal force sensor

68

Narrowing

70

End of tour

72

Grip surface

74

Locking shoulder

76

End of the slide

77

top

78

electric contact

79

Contact spring

80

Contact point of the plug

81

Contact point of the measuring arms

84

Fixation

86

Fixation opening

88

Fastening bolts

90

Connector holder

92

collar

94

Connector receptacle

96

Handle

A.

Contact point

B.

Contact point

C.

Contact point

D.

Contact point

E.

Direction of insertion

F.

Contact point

G

Contact point

H1

Height of the measuring range

H2

Height of the measuring range with the slide inserted

L.

Longitudinal axis

N

Normal force

S.

Mating direction

x

Longitudinal direction

y

Transverse direction

z

Height direction

Claims (15)

Measuring instrument (1) for measuring a normal force (N) acting on at least one contact point (81) of an electrical contact (78), with at least two measuring arms (2, 2 ') running next to one another, with at least one measuring arm (2, 2') at least is provided with at least one normal force sensor (12) at the at least one contact point (81), characterized in that the measuring instrument (1) has a position between the measuring arms (2, 2 ') in an insertion direction (E) essentially perpendicular to the normal force (N ) has insertable slide (4). Measuring instrument (1) Claim 1 , characterized in that the measuring arms (2, 2 ') are biased towards each other. Measuring instrument (1) Claim 1 or 2 , characterized in that the measuring arms (2, 2 ') are pushed apart by the inserted slide (4). Measuring instrument (1) according to one of the Claims 1 to 3 , characterized in that the at least one normal force sensor (12) can be discolored by the normal force (N). Measuring instrument (1) according to one of the Claims 1 to 4th , characterized in that the at least one normal force sensor (12) is plastically deformable by the normal force (N). Measuring instrument (1) according to one of the Claims 1 to 5 , characterized in that the measuring instrument (1) has a holder (10) for positioning the measuring arms (2, 2 '), the measuring arms (2, 2') extending away from the holder (10). Measuring instrument (1) Claim 6 , characterized in that the holder (10) has a guide (33) for inserting the slide (4) between the measuring arms (2, 2 '). Measuring instrument (1) according to one of the Claims 1 to 7th , characterized in that the measuring arms (2, 2 ') one to a free end of the measuring arms (2, 2 ') have increasing material thickness in the direction of the normal force (N) transversely to the insertion direction (E). Measuring instrument (1) according to one of the Claims 1 to 8th , characterized in that the measuring instrument (1) comprises a plurality of slides (4) with different material thicknesses. Measuring instrument (1) according to one of the Claims 1 to 9 , characterized in that the measuring instrument (1) has at least one clamping plate (6) for fastening the normal force sensor (12). Measuring instrument (1) according to one of the Claims 1 to 10 , characterized in that the measuring instrument (1) has at least one stop (52) for positioning the at least one normal force sensor (12). Measuring instrument (1) according to one of the Claims 1 to 11 , characterized in that the slide (4) is provided with a stop (74) for blocking the movement in the insertion direction (E). Method for measuring a normal force (N) acting on at least one contact point (81) of an electrical contact (79), comprising the following steps: - Inserting two measuring arms (2, 2 ') into the plug to be tested (13); - Introducing a slide (4) between the measuring arms (2, 2 '); - Measuring the normal force (N) at at least one contact point (81) of a measuring arm (2, 2 ') provided with at least one normal force sensor (12). Procedure according to Claim 13 , wherein the normal force (N) is measured simultaneously at a plurality of contact points (81). Procedure according to Claim 14 , with at least one separate normal force sensor (12) being attached to the at least one measuring arm (2, 2 ') before the measuring arms (2, 2') are inserted and removed again after being pulled out of the plug (13).

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