DE20008214U1 - Locking pin for checking the mechanical fit of elements in housings - Google Patents

Description

Patent Attorneys Lawyers Munich Stuttgart

Dr. jur. Alf-Olav Gleiss. Dip!.-Ing. PA Rainer Große, Dipl.-Ing. PA
Dr. Andreas Schrell. Dipl.-Bid. PA
Torsten Armin Krüger, Attorney
Nils Heide. Attorney

PA: Patent Attorney

European Patent Attorney
European Trademark Attorney

RA: Attorney at Law, Attomey-at-law D-70469 STUTTGART MAYBACHSTRASSE 6A Telephone: +49(0)711 81 45 55 Fax: +49(0)711 81 30 32 Telex: 72 27 72 jura d e-mail: [email protected]

D-80469 MUNICH MORASSISTRASSE 20 Telephone: +49(0)89 21578080 Fax: +49(0)89 21578090 e-mail: [email protected]

In cooperation with

Shanghai Hua Dong Patent Agency Shanghai, China

Utility model application

Locking pin for checking the mechanical fit of elements in housings

Feinmetall GmbH Zeppelinstrasse 8

71083 HERRENBERG

16222t GR-to-ne
09 May 2000

Track X Size*

Patent Attorneys Lawyers
Munich Stuttgart

Description

The invention relates to a locking pin for testing the mechanical fit of elements, in particular electrical contact elements, in housings, according to claim 1.

Locking pins of the type mentioned here are used to test the mechanical fit of, for example, plugs in connectors or in housings. The locking pin is used to check whether the element is held with a desired holding force in the housing, which is usually made of plastic, for example by being locked into a holder. In order to be able to test the relatively high holding forces, the elements must be subjected to high forces. In order to compensate for tolerances, the locking pins must be flexible. The locking pins must therefore be able to apply a high spring force. Since in many cases several locking pins are arranged in a holding plate so that several elements lying close together can be tested at the same time, a small outer diameter is required for the locking pins so that they can be arranged close together.

It is therefore an object of the invention to provide a locking pin of the type mentioned above, which

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has a relatively small outer diameter and can be used to apply a high spring force to the element to be tested.

To solve the problem, a locking pin with the features of claim 1 is proposed. This has a sleeve in which a piston is guided so that it can move longitudinally against spring force. The spring force is applied by at least two springs which are arranged one behind the other on the piston as seen in the longitudinal direction of the piston and are each supported with one end on the piston and with the other end on the sleeve. Due to the interconnected springs, the spring force with which the piston can be subjected to check the mechanical fit of elements, in particular electrical contact elements, for example AMP plugs, in housings, is very high. Because the springs are connected in parallel and arranged one behind the other, an extremely small outer diameter of the locking pin can be achieved in relation to the spring force.

In a preferred embodiment, the springs are designed as helical springs that wrap around the piston, and whose spring constant can be the same or different. By selecting the springs accordingly, an exact, predeterminable spring force can be achieved for testing the mechanical fit of the elements arranged in a housing. The spring force of the helical springs can be generated by compression or tension.

According to a further development of the invention, stops are provided on the piston for supporting

of the springs. These are attached to the piston, connected to it in one piece or supported on a shoulder of the piston and are displaced against the force of at least one spring when the piston is displaced in its longitudinal direction. This means that at least one stop is assigned to each spring, which exerts a compressive or tensile effect on the spring when the piston is displaced within the sleeve.

An advantageous embodiment of the locking pin is characterized in that counter-stops are arranged on the piston, which are movable relative to the piston, to support the springs and which interact with/rest against shoulders of the sleeve. When the piston is displaced within the sleeve in its longitudinal direction, one of the springs is pressed by means of a stop, preferably against a counter-stop which interacts with the spring and which - as mentioned - is supported on at least one shoulder of the sleeve, so that the spring is compressed and applies a corresponding spring force to the piston.

In another embodiment of the locking pin, at least one of the springs is not pressurized in order to generate a desired spring force, but the spring is coupled to the associated stop connected to the piston in such a way that the spring is subjected to tensile stress when the piston is displaced longitudinally within the sleeve, whereby the tensile effect causes the force required to test the mechanical

The spring force required to ensure the mechanical fit of the elements is generated.

Furthermore, an embodiment of the locking pin is preferred which is characterized in that the springs are arranged on sections of the piston with a reduced diameter. The outer diameter of the springs is preferably only so large that the springs do not protrude in the radial direction, or only protrude to a small extent, beyond the section of the piston with the largest diameter. This makes it possible to achieve a small outer diameter of the locking pin.

In a further embodiment of the locking pin, a holding element is held on the piston so that it can be moved longitudinally and rotated. The holding element has a thread which is screwed to a counter thread of the sleeve which accommodates the springs and the piston. The detachable screw connection means that the piston and the sleeve can be separated from one another again without causing any damage, for example for cleaning purposes or to replace individual parts of the locking pin. The displacement path of the holding element on the piston is preferably the same as the displacement path of the piston within the sleeve. The maximum displacement path of the holding element on the piston and the maximum spring travel of the springs, i.e. the extent to which they are compressed or pulled apart when the piston is moved within the sleeve, are also preferably the same or at least essentially the same.

Also preferred is an embodiment of the locking pin in which the piston has a contact tip which interacts with the element, for example an electrical contact element, and which has at least one flattened area. In the area of the contact tip, the piston therefore does not have a rotationally symmetrical cross-section. In order to contact the element, the contact tip must be rotationally aligned with the element, i.e. brought into a certain rotational angle position with respect to the element. Only then can the contact tip be inserted or plugged into the element which has an opening, receptacle or the like. The flattened area therefore serves for the exact rotational alignment of the piston with respect to the element to be tested, with the number of flattened areas on the contact tip determining the number of rotational angle positions of the piston in which it can be inserted into the element by a relative movement in the direction of its longitudinal central axis.

If the element to be tested is formed, for example, by an AMP plug, which is locked into a housing preferably made of plastic, the contact tip is designed in such a way that it can be inserted into the AMP plug and apply a desired test/spring force to it. In this embodiment, the shape of the contact tip is preferably identical to that of a plug part for the AMP plug, which is tongue-shaped and has an essentially rectangular cross-section. It is clear that the shape of the contact tip

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can be varied practically as desired, provided that it has at least one flattened area for aligning the piston around its longitudinal central axis relative to the element to be tested. The contact tip can therefore also have a three-, five- or six-octagonal cross-section, for example.

According to another design variant of the locking pin, the contact tip is rotationally symmetrical about the longitudinal axis of the piston, so that in order to test an element, it is not necessary to align the piston or the contact tip with respect to the element.

Finally, an embodiment of the locking pin is preferred which is characterized in that the piston is mounted in a position-oriented manner in the sleeve by means of an anti-twist device. The anti-twist device is designed in such a way that it enables the piston to be displaced within the sleeve in the direction of its longitudinal center axis and prevents the piston from pivoting relative to the sleeve about its longitudinal center axis.

Further advantageous embodiments emerge from the remaining subclaims.

The invention is explained in more detail below with reference to the drawings. They show:

Figure 1 is a perspective view of an embodiment of a piston for the locking pin according to the invention;

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Figure 2 shows a longitudinal section through a sleeve for receiving the piston shown in Figure 1;

Figure 3 is a perspective view of the sleeve according to Figure 2;

Figure 4 is a plan view of the anti-twisting end of the sleeve shown in Figures 2 and 3;

Figure 5 shows a longitudinal section through an embodiment of the locking pin;

Figure 6 is a front view of the contact tip of the piston of the locking pin according to Figure 5, and

Figure 7 shows another embodiment of the locking pin, which is firmly attached to a holding plate

is mounted.

The locking pin described below can generally be used to test the mechanical fit of elements held in housings by friction and/or form-fitting. For the purposes of example only, it is assumed that the locking pin is used to test an electrical contact element, in particular an AMP plug, which is held in a housing usually made of plastic by means of a locking connection. In one application example, the electrical contact element is part of a wiring harness for a motor vehicle.

Figure 1 shows a perspective view of part of an embodiment of a locking pin 1, namely a piston 3, which is rod- or tube-shaped and here consists of an electrically conductive material. The piston 3 has a contact tip 5 at its first end, which can be brought into contact with the respective contact element in order to test the mechanical fit of the electrical contact elements (not shown) arranged in the housing. The locking pin 1 shown in Figure 1 is used here specifically for testing AMP plugs. The shape of the contact tip 5 is designed here according to the shape of a plug part for the AMP plug, so that it can be inserted into the AMP plug, which has a receptacle for the electrical plug part. The contact tip 5 here has two flattened areas 7 and 9 arranged on opposite sides, whereby an essentially rectangular cross-section is formed and the contact tip 5 takes on the tongue shape of an electrical plug part for the AMP plug.

The contact tip 5 is followed by a first longitudinal section 11 and a second longitudinal section 13, each of which has a rotationally symmetrical cross section. The second longitudinal section 13 is smaller in diameter than the first longitudinal section 11. Due to the difference in diameter, an annular shoulder 12 is formed, which can be seen in Figure 5. The second longitudinal section 13 is followed by a third longitudinal section 14 with a smaller diameter, whereby here too

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Due to the jump in diameter, an annular shoulder 16 is formed, as shown in Figure 5.

Stops 15, 17 are arranged on the piston 3, which are ring-shaped here and are held longitudinally displaceably on the piston 3. The first stop 15 is arranged on the second longitudinal section 13 of the piston 3 directly in the area of the shoulder 12 formed by the difference in diameter between the first and second longitudinal sections 11, 13, which cannot be seen in the illustration according to Figure 1, while the second stop 17 is located on the shoulder 16 on the third longitudinal section 14.

Furthermore, counter stops 19, 21 are arranged on the piston 3, which are ring-shaped and can be moved relative to the piston 3 in the direction of its longitudinal axis, as indicated by double arrows 23. The first counter stop 19 is arranged between the first stop 15 and the second stop 17 and the second counter stop 21 is arranged between the second stop 17 and a fourth longitudinal section 25 of the piston 3 forming the end of the piston 13.

The locking pin 1 further comprises two springs 27, 29, of which the first spring 27 is arranged between the first stop 15 supported on the shoulder 12 and the displaceable first counter stop 19 and the second spring 29 is arranged between the second stop 17 supported on the shoulder 16 and the second counter stop 21 displaceable relative to the piston 3. As can be seen from Figure 1, the springs 27, 29 are arranged as the piston

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3 spiral springs are formed in the region of the second longitudinal section 13 or third longitudinal section 14.

The fourth longitudinal section 25 of the piston 3 has a cross-section essentially in the shape of a dihedral, which is introduced into a correspondingly formed opening in a sleeve 31 shown in Figure 2 in order to secure the piston 3 against rotation relative to the sleeve, which will be discussed in more detail below.

Furthermore, a holding element 30 is held on the piston 3 so as to be longitudinally displaceable and rotatable, which has a first longitudinal section with an external thread (not shown in Figure 1) and a second longitudinal section designed as a square. The thread of the holding element 3 can be screwed to a counter thread of the sleeve 31 shown in Figure 2. The square can be used to act on the holding element 30 with a suitable tool, for example an open-end wrench or pliers, in order to pivot or rotate it about the longitudinal center axis of the piston 3. This makes it easy to screw the holding element 30 to the sleeve 31 or to loosen an existing screw connection between the holding element 30 and the sleeve 31. The holding element 30 is arranged on the piston 3 between the first stop 15 and the contact tip and can be moved between these in the axial direction on the piston 3.

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Figure 2 shows a longitudinal section through an embodiment of a sleeve 31, which is part of the locking pin 1 and in which the piston 3 shown in Figure 1 is held so as to be longitudinally displaceable. The sleeve 31 has an outer contour that is rotationally symmetrical to its longitudinal center axis 33. On the outside of the sleeve 31, an annular shoulder 35 is provided, which is formed by a difference in diameter between a first longitudinal section 37 and a second longitudinal section 39 of the sleeve 31. The sleeve 31 also has a stepped through-bore 41 that is aligned with the longitudinal center axis 33 of the sleeve 31. Between a first bore section 43 and an adjoining second bore section 45, which is smaller in diameter than the first bore section 43, a first, circumferential shoulder 47 is formed, on which the first counter-stop 19 on the piston 3 is supported in the assembled state when the piston 3 is displaced to the right in its longitudinal direction. Between the second bore section 45 and a subsequent third bore section 49, which is smaller in diameter than the second bore section 45, a further, second shoulder 51 is formed, on which the second counter-stop 21 on the piston 3 is supported. At the end of the third bore section 49, the through bore 41 opens into a slot 53 made in the front side of the sleeve 31, which runs parallel to the longitudinal center axis 33 of the sleeve 31 and whose height H is equal to or preferably slightly larger than the thickness D of the piston in the region of its fourth longitudinal section 25, which in cross section has the shape of a dihedral (Figure 1).

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When assembling the locking pin 1, the piston 3 must be rotationally aligned with respect to the sleeve 31 such that the fourth longitudinal section 25 of the piston 3 can engage in the slot 53 in the sleeve 31. Due to the mutually adapted shapes and geometries of the slot 53 and the fourth longitudinal section 25, an anti-twisting device is formed which supports the piston 3 in a position-oriented manner in the sleeve 31, i.e., rotation of the piston 3 about its longitudinal center axis relative to the sleeve 31 is prevented, while longitudinal displacement of the piston 3 within the sleeve 31 is permitted.

In the area of the bore section 43, an internal thread (not shown in Figure 2) is introduced into the through bore 41, into which the holding element arranged on the piston 3 is screwed.

Figure 3 shows a perspective view of the sleeve 31 described with reference to Figure 2 and Figure 4 shows a front view of the end of the sleeve 31 having the slot 53. The same parts are provided with the same reference numerals, so that reference is made to the description of the previous figures.

Figure 5 shows an embodiment of the locking pin 1 in the assembled state, the parts of which are described with reference to Figures 1 to 4. The same parts are provided with the same reference numerals, so that reference is made to the description of the previous figures.

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The piston 3, which has the holding element 30, the stops 15 and 17, the counter stops 19 and 21 and the springs 17, 19, is inserted into the through holes 41 of the sleeve 31. The sleeve 31, which - as can be seen from Figure 5 - has an internal thread in the mouth area of the through hole 41, is screwed to the holding element 30 arranged on the piston 3, which has a corresponding external thread. When the locking pin is assembled, the longitudinally displaceable first and second counter stops 19, 21 of the piston 3 are pressed by the springs against the respectively associated shoulder 47 or 51 in the through hole 41 of the sleeve 31 and are supported on these.

The function of the locking pin 1 is explained in more detail below using a test procedure: A relative movement between the locking pin 1 and the electrical contact element to be tested, which is locked in a housing, brings the piston 3, i.e. its contact tip 5, into contact with the contact element. If the contact element is an AMP plug, the contact tip 5 is inserted into the plug. The piston 3 is then pressed against the contact element or the contact element is pressed against the piston 3 with great force. If the holding force of the contact element in the housing is - as desired - large enough, i.e. the contact element is held securely in the housing and rigidly in the direction of displacement of the piston 3, the piston 3 is pushed in its longitudinal direction when the spring force exerted on the piston 3 by the springs 27, 29 is exceeded.

5- against the spring force. As a result, the end 55 of the piston 3 opposite the contacting tip 5 is pushed out of the sleeve 31. A displacement of the piston 3 in the longitudinal direction therefore only takes place when the electrical contact element is held firmly in the housing. With the aid of a device (not shown) which has at least one sensor, the longitudinal displacement of the piston 3 can be detected, for example at the end 55 pushed out of the sleeve 31. If the electrical contact element is not locked into the housing in the desired manner, the piston 3 is not moved because the spring force acting on it is greater than the holding forces of the contact element. As a result, the electrical contact element is pushed into or out of the housing, depending on the design of the receptacle for the contact element in the housing. If there is a faulty connection between the contact element and the housing, the sensor cannot detect a longitudinal displacement of the piston 3, so that, for example, a corresponding signal can be output.

Since the piston 3 in the locking pin 1 described with reference to the previous figures consists of an electrically conductive material, during or after the test of the mechanical fit of the electrical contact element, this can also be tested for continuity and insulation with respect to another electrical contact element arranged adjacently and also held in the housing.

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can be implemented, for example, by bringing the end 55 of the piston 3, which slides out of the sleeve 31 when the electrical contact element is properly mechanically seated in the housing, into contact with an electrical test device that applies an electrical test voltage to the piston 3. The locking pin 1 can therefore be used to carry out a mechanical and an electrical test of the contact element. One example of using the locking pin 1 is a wiring harness for a motor vehicle, which is usually finished and its contact elements are tested before it is installed in the motor vehicle.

"15 will be checked.

Figure 6 shows a plan view of the contact tip 5 of the piston 3, which has a substantially rectangular cross-section due to the flattened areas 7 and 9. In Figure 6, the four flat surfaces 57 of the square provided on the holding element 30 can also be seen.

Figure 7 shows an example of the use of the locking pin 1. Parts that correspond to those already described with reference to Figures 1 to 6 are provided with the same reference numerals, so that reference is made to the description of the previous figures. The sleeve 31 of the locking pin 1 is held immovably in a through-opening of a holding plate 59. The holding plate 59 is preferably arranged in a stationary manner, which means that in order to check the mechanical fit of an element held in a housing, the housing is relatively movable relative to the holding plate 59.

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and thus the locking pin 1. If the holding force of the element in the housing is sufficiently large, the piston 3 is displaced longitudinally in the sleeve 31 against the spring force, so that its end 55 opposite the contact tip 5 is moved out of the sleeve 31 and displaced against a test probe 61 of a test device (not shown in detail). A longitudinal displacement of the piston 3 can therefore be detected by means of the test probe 61, so that a desired mechanical fit of the contact element in the housing can be checked in a simple manner. If the element to be tested is an electrical contact element, the piston 3 can be subjected to a test voltage by means of the test probe 61, so that the electrical contact element arranged in the housing can be tested for continuity and insulation with respect to other contact elements in the housing 0 in addition to the mechanical test.

Claims (9)

1. Locking pin ( 1 ) for testing the mechanical fit of elements, in particular electrical contact elements, in housings, with a sleeve ( 31 ) in which a piston ( 3 ) is guided so as to be longitudinally displaceable against spring force, wherein the spring force is applied by at least two springs ( 27 , 29 ) which, viewed in the longitudinal direction of the piston ( 3 ), are arranged one behind the other on the piston (3) and are each supported with one end on the piston ( 3 ) and with the other end on the sleeve ( 31 ). 2. Locking pin according to claim 1, characterized in that the springs ( 27 , 29 ) are designed as helical springs winding around the piston ( 3 ). 3. Locking pin according to one of the preceding claims, characterized in that stops ( 15 , 17 ) for supporting the springs ( 27 , 29 ) are arranged on the piston ( 3 ). 4. Locking pin according to one of the preceding claims, characterized in that counter-stops ( 19 , 21 ) which are displaceable relative to the piston ( 3) are arranged on the piston (3 ) for supporting the springs ( 27 , 29 ), which cooperate with shoulders ( 47 , 51 ) of the sleeve ( 31 )/rest against shoulders ( 47 , 51 ) of the sleeve ( 3 ). 5. Locking pin according to one of the preceding claims, characterized in that the springs ( 27 , 29 ) are arranged on a reduced-diameter portion ( 13 ) of the piston ( 3 ). 6. Locking pin according to one of the preceding claims, characterized in that a holding element ( 30 ) is held on the piston ( 3 ) in a longitudinally displaceable and rotatable manner. 7. Locking pin according to one of the preceding claims, characterized in that the holding element ( 30 ) has a thread which is screwed to a counter thread of the sleeve. 8. Locking pin according to one of the preceding claims, characterized in that the piston ( 3 ) has a contacting tip ( 5 ) which interacts with the element and which has at least one flattened area ( 7 , 9 ) or is rotationally symmetrical. 9. Locking pin according to one of the preceding claims, characterized in that the piston ( 3 ) is mounted in a position-oriented manner in the sleeve ( 31 ) by means of an anti-twist device.