Rotary potentiometer.

The invention relates to a rotary potentiometer in which a resistance track disposed internally on one cylindrical wall of a housing in which a rotor is mounted rotatably about the cylinder axis, to a soft resting against the resistance track grinder is attached.

Such a rotary potentiometer is described in DE-OS 36 31 058th In this potentiometer, the cylinder axis is pushed into the housing when assembling the rotor in the axial direction. The wiper has to slide over the edge of the resistive track. This is unfavorable when the rim forming a step. Because the brush can be bent at the stage during insertion.

Are besides the resistance track in the housing, additional parts and / or connecting lines located, then an axial insertion of the rotor with the grinder is especially critical because it bent not only the grinder, but also the components and connection lines can be damaged.

In EP 0157666 A1 a similar rotary potentiometer is described. Also in this rotor with the grinder in the axial direction is inserted into the housing. A V-shaped space to facilitate the insertion of the grinder. This space is for the accommodation of functional parts are not available, so that space is lost.

In DE-AS 1,790,163 a Kleinpotentiometer is described in whose closable with a cover housing axially parallel a grinder spindle and a resistance coil are arranged. For a rotary potentiometer of the aforementioned type, this arrangement is not usable.

The object of the invention is to propose a rotary potentiometer of the aforementioned type, in which during the mounting an axial insertion of the grinder is avoided in the housing.

According above object is achieved with a rotary potentiometer of the aforementioned type in that the circumference of the wall is an opening through which the rotor can be inserted into the cylinder axis radial direction and which can be closed with an insert.

This is achieved in that the slider does not slip during installation on the edges of the resistance path and also not in this arranged conductor paths and components. Mutual damages are avoided without a special care is needed when inserting the rotor.

In case you have a specific space needs to be provided. The insert itself may carry functional elements of the rotary potentiometer. It is attached only after the insertion of the rotor.

In a preferred embodiment of the invention the resistive track is applied to a carrier foil which is inserted through the opening in the housing. It is thus a positionally correct arrangement of the resistance path easier.

Preferably, the rotor on the insert is itself mounted rotatably, wherein the rotor axis of rotation is inserted into the opening in the insert Zylindereachse. The assembly is further facilitated. For the rotor with the grinder and its electrical connection to the corresponding terminal in use, for example by a coil spring, can then be mounted outside of the housing to the insert. After insertion of the insert into the housing, the rotor is in the correct position and the case closes the opening.

Further advantageous embodiments result from the further dependent claims and the following description. In the drawings:<ul><li>Figure 1 shows an exploded view of a rotary potentiometer,</li><li>Figure 2 is a resistive track of the rotary potentiometer in the developed position,</li><li>3 shows a section of a rotary potentiometer along the line III of Figure 5,</li><li>4 shows a section along line IV and</li><li>5 shows a longitudinal section along the line VV of FIG. 4</li></ul>

A rotary potentiometer comprises a housing (1) forming an about 180 ° extending cylindrical wall (2) and two tangentially-extending wall leg (3, 4) and an upper (5) and a lower wall portion (6). The cylinder axis of the wall (2) is labeled (7). Edges (3 ', 4', 5 ', 6') of the wall leg (3, 4) or the wall parts (5, 6) enclose an opening (8).

In the housing (1) a flexible film (9) is inserted, which carries a resistance track (10). This part-cylindrical case runs as the wall (2). It covers more than 180 °. The film (9) is shown in Figure handled. 2 It has conductor tracks (11, 12) which are connected via diodes (13) connected to individual electrodes (14). The individual electrodes (14) are located at the four edges of the resistance path (10). On a flexible extension (9 ') of the film (9), the conductor tracks (11, 12) can be connected.

The resistance track (10) may be laminated onto the film (9). The film may be glued into the casing (1). It is also possible the resistance track (10) directly on the wall (2) apply. The diodes (13) can be applied to these by means of a conductive adhesive due to the comparatively large opening (8) also after insertion of the film (9). Determining it is then not affected by mechanical stresses of bending of the film (9). Is already the film used (9) fitted with diodes (13), then their arrangement beneficial to the parts of the film (9), the rest after the insertion of flat wall legs (3, 4); also as mechanical stresses due to the bending of the film (9) are avoided at the diodes (13).

There is provided an insert (15) whose cross-section corresponds to the free cross-section of the opening (8). The insert (15) a bearing pin (16) for a rotor (17) is formed, which carries a slider (18).

The insert (15) has a partially cylindrical gripping surface (19) is formed, the size and radius of the resistive track (10). In addition to the gripping surface (19), a stop web (20) is provided, the stop lugs (21, 22) of the rotor (17) are associated. These serve to limit the rotary movement of the rotor (17) on the extension of the resistance track (10) or the gripping surface (19).

Outside a plug (23) is attachable to the insert (15) electrically connecting the conductor tracks (11, 12) and the gripping surface (19).

The rotor (17) is rotatable on the bearing journal (16) not only about the rotation axis (24) but displaceable in the axial direction thereof. He has a receptacle (25) for a drive rod (26). The receptacle (25) is provided with tangential slots (27), which take the picture (25) semi-rigid, in order to compensate an axial offset between the drive rod (26) and the rotor (17). The drive rod (26) and the receptacle (25) are designed so that the drive rod (26) rotationally fixed and axially fixed in the housing (25) can be inserted. To the wall part (5) of the housing (1) a passage (28) for the drive rod (26) is formed.

The installation of the rotary potentiometer described is done like this:

After insertion of the film (9) in the housing (1) of the rotor (17) is plugged onto the bearing journal (16), so that the stop web (20) between the two stop lugs (21, 22) and the one end ( 18 ') of the slider (18) on the gripping surface (19) abuts. Subsequently, the insert (15) is inserted into the opening (8) and inserted between the wall legs (3, 4) and the wall parts (5, 6) in the housing (1), said surfaces (15 ') of the insert (15) provide suitable guidance. In the inserted position of the insert (15) by means of not shown catch means with the housing (1) can be latched. In this position, aligned with the cylinder axis (7) and the axis of rotation (24). The end (18˝) of the slider (18) lies resiliently against the resistance path (10).

Subsequently, the drive rod (26) through the passage (28) into the receptacle (25) of the rotor (17) is inserted and connected to the plug (23). Now, the drive rod (26) in the direction of arrow (D) is rotated or in the direction of arrow (H) shifted, engages the slider (18) on the resistance track (10) a corresponding voltage from which via the conductor tracks (11, 12), for example, clocked with alternating polarity to the resistive track (10) is introduced.

In the embodiment according to Figures 3 to 5 pins (29) are inside of the wall legs (3, 4) are provided to which corresponding cutouts (37) are associated with the slide (9). This can be the film (9), which extends along the wall leg (3, 4), arranged in a simple manner in the correct position in the housing (1). Due to their inherent elasticity, the film (9) by the pin (29) is stretched flush with the cylindrical wall (2). The insert (15) are contact springs (30) for contacting the conductor tracks (11, 12) is provided (see FIG. 3, 5). On the insert (15) has a contact spring (31) is further arranged, which with the one gripping surface (19) connected to the conductor track (32) contacted (see FIG. 4). The conductor track (32) is guided around a rounded portion (33) of the insert (15). It ends in a recess (34). There, the contact spring (31) is applied to it.

The comparison of Figures 3 and 4 shows the range of rotation of the rotor (17) and corresponding to the circumferential extension of the resistive track (10) and the gripping surface (19).

The contact springs (30, 31) are contacted by the insertion of the plug (23).

In the embodiment of Figure 5, a bellows (35) for improving the sealing effect is provided in the region of the leadthrough of the drive rod (26). The bellows (35) is held with its one end on the housing (1). Its other end is located on the rotor to (17). also a latching tongue (36) is shown in Figure 5, with the drive rod (26) axially fixed to the rotor (17) is fixable.

It is also possible the rotor (17) links to search through. Needless then the gripping surface (19). The gripping surface (19) can also be arranged in the axial direction in addition to the resistance track.

Numeral list 03/88

<ul><li>1 housing</li><li>2 wall</li><li>3.4 wall leg</li><li>3 ', 4' wall leg edge</li><li>5.6 upper or lower wall portion</li><li>5 ', 6' wall part edge</li><li>7 cylinder axis</li><li>8 opening</li><li>9 foil</li><li>9 'film projection</li><li>10 resistance path</li><li>11 interconnect</li><li>12 interconnect</li><li>13 diode</li><li>14 single electrode</li><li>15 applications</li><li>15 'use area</li><li>16 journals</li><li>17 rotor</li><li>18 grinder</li><li>18 ', 18˝ grinding end</li><li>19 gripping surface</li><li>20 stop web</li><li>21 stop lug</li><li>22 stop lug</li><li>23 connector</li><li>24 axis of rotation</li><li>25 recording</li><li>26 drive rod</li><li>27 slot</li><li>28 implementation</li><li>29 pin</li><li>30 contact spring</li><li>31 contact spring</li><li>32 interconnect</li><li>33 rounding</li><li>34 recess</li><li>35 bellows</li><li>36 latching tongue</li><li>37 free cut</li><li>D rotation</li><li>H Hub</li></ul>