DE1665310A1 - Potentiometer - Google Patents

Description

K / Hs MUnchen-Pullach, January 28, 1966

4373

PAINTON & COMPANY LIMITED, Bembridge Drive, Kingsthorpe Northampton, Northamptonshire, England

Potentiometer.

The invention relates to an electrical resistor in general and in particular a manually adjustable resistance component such as a potentiometer. Such resistance have terminals for insertion into an electrical circuit and the electrical resistance between the terminals is adjustable. In the following, "flags" should be understood to mean electrical connections such as tabs or clamps that are used for this purpose serve to insert the variable resistor into a circuit.

A well-known potentiometer has an arc shape or a circular arc shape arranged resistance element and one of Hand around the axis of the resistance element rotatable carrier, on which in turn the customer is held, which in Engagement with the resistance element is. A flag of the Potentiometer is electrically connected to the consumer, e.g. by means of a slip ring and at least one other Flag is on the resistance element, usually one Connected end. Usually a shaft is integrally connected to the carrier and carries a button at the end, during its rotation, therefore, the electrical resistance ζ wi a ο hen the flags can be changed 1st.

BAD ORfGINAL

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In the construction of electronic devices, there is an increasing need for increasingly smaller electrical components, which perform the same functions as the known components with larger dimensions. Although the above described known potentiometer with a circular arc Resistance element can also be produced with small dimensions, it cannot be done by hand with the required accuracy can be set.

This fact has led to the development of further adjustable Resistance components out. A potentiometer with a screw is known, which is in a housing has a straight resistance element parallel to a lead screw runs, the slotted one End protrudes from the housing at one end. The lead screw is rotatable by means of a screwdriver and is part of a Pick-up element is arranged around this guide screw. The pickup connects the resistance element with a contact strip running parallel to it and is in engagement with the guide screw. The customer is further in engagement with guide surfaces, which one Rotation of the same is prevented when the guide screw is rotated, so that the rotary movement in this type of construction the guide screw is converted into a straight movement of the customer. In this way one achieves a minor one Movement of the pickup with a relatively large movement of the guide screw head and one achieves with it an exact setting option for the customer. However, this advantage is offset by the disadvantage that because of the rectilinear resistance element, the potentiometer must be relatively long, if over a relatively large resistance range a precise setting should be possible. This realization led to the development of another potentiometer

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with a worm gear drive, with which one does not have a long Resistance element must be accommodated in a housing that is becoming very long as a result, and still has a precise setting option Has. In this potentiometer with worm gear drive, the resistance element is circular and engages a rotatable pickup supported by a suitable carrier. This holder is centrally stored within the resistance element. The carrier is designed like a gear on the circumference and its Teeth are in engagement with a tangentially arranged worm shaft. Outside the housing is on the Worm gear shaft provided a head with a slot and the Schneclcenradwelle can thereby by means of a screwdriver ^ to be turned around. Due to the engagement of the gear-like circumference of the carrier with the worm wheel, by rotation on the slotted head the position of the pickup with respect to the resistance element can be finely adjusted. Though that just described potentiometer with worm gear with given external dimensions a better Peineinstellbarkeit the position of the consumer with respect to the resistance element is permitted than with the one with a lead screw provided potentiometer is the case, the worm wheel potentiometer has a disadvantage, which also occurs with the potentiometer with guide screw. These two potentiometers are fine-tuned using a screwdriver and the small dimensions of the slot provided head make adjustment difficult, especially if the potentiometer is in a difficult-to-reach place is arranged if you do not have a special screwdriver with exactly the right dimensions Has. Adjustment by hand is difficult and in many cases. Cases impossible and one can also only see with very little accuracy from the outside which rotary position the

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has slotted head. With that you can have trouble with me from the outside without measuring the resistance, see its size or otherwise display it.

The invention is aimed at creating a potentiometer which can be adjusted by hand with the greatest possible accuracy.

The invention thus relates to a manually adjustable potentiometer with an arcuate arrangement opposite one Resistance element rotatable pickup, which over a reduction gear is rotatable by hand, and consists essentially in that a rotary knob is provided for actuation is, the circumference of which is substantially parallel to the direction of movement of the collector.

The rotary knob is arranged in two ways so that part of its circumference is easy to adjust by means of the finger is accessible. The use of the gearbox has the advantage of a more precise rotation setting of the customer supporting carrier compared to the known potentiometers, in which there is a manual adjustment but no reduction gear was provided.

In one embodiment of the invention, the potentiometer a housing made of insulating material, from which the terminal lugs protrude to the outside are connected to an arcuate electrical resistance element inside the housing. On a rotating support an electrical pickup is attached and engaged with the resistive element. By rotating the carrier thus changed the position of the consumer on the resistance element. The consumer is electrically connected to one of the '

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BATH ORIGINAL

Terminal lugs connected and the other terminal lug is electrically connected to the resistance element. A knob with protruding from the housing at an accessible point Scope is in operative connection with a reduction gear, which mechanically this knob and connects the carrier, so that a given rotational movement of the circumference of the rotary knob is a smaller parallel to it Movement of the carrier results. The parallel movement of the carrier can be in the same direction as the of the rotary knob or opposite to it.

In a further practical embodiment of the invention, an insulating housing is also provided with external connection lugs, which are connected in the interior of the housing to the resistance element arranged in an arc. A rotatable disk is assigned to the carrier, which is provided with a scale on part of its circumference and protrudes from the housing. An electrical pick-up is provided on this carrier disk, which is in engagement with the resistance element, as a result of which the position of the pick-up on the resistance element is changed by means of rotation of the carrier. The pickup is electrically connected to one flag and the other flag is electrically connected to the resistor element. Furthermore, a rotary knob is provided next to the carrier disk, which also protrudes with part of its circumference from the housing at a point accessible by hand. The rotary knob is mechanically connected to the carrier via a reduction gear , whereby an adjustment is possible in the manner described above.

♦ With the help of the invention can « build on a potentiometer of very small dimensions», especially if the rotary knob and the support door are arranged coaxially with the resistance element

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BATH

are. In two ways, the carrier has a driven one Disc with a flange-like perimeter, on the outside a Scale or markings are provided to indicate the exact position of the wearer.

Although the resistance element could be attached to the carrier, the resistance element is preferably fixed in place and the carrier is provided with the pickup , such as with contact strips or a sliding contact that can be guided along the resistance element by rotating the carrier.

You can only use a variable resistor or a potentiometer train according to the invention. A speed reduction of 1o: 1 is preferably used between the rotary knob and carrier on "and for this purpose can be a single transmission gear can be provided with external teeth, which mesh with teeth on a shaft on the rotary knob and wherein a shaft portion provided with gear teeth meshes with teeth formed on the periphery of a hub on the carrier ™ sit. A slip clutch can also be provided.

Further advantages and details of the invention emerge from the description of an exemplary embodiment which now follows referring to the drawing. In this show:

! Figure 1 shows a manually adjustable resistance

^{1 of} the invention in Torrn of a potentiometer; • Figure 2 is a side view of the potentiometer

Pigur 1 |

3 shows the items dee potentiometer apart gesogener Ansichtj

0ÖÖÖ84 / 073A

Figure 4 shows the parts drawn apart

Potentiometer seen from the other side;

FIG. 5, in the axial direction, a view of the gear wheel for the potentiometer; and

Figure 6 is a side view of the gear of Figure 5. '*

The potentiometer shown in a view in Figures 1 and 2 is arranged within a housing 1, which only 1.63 cm long, 0.75 cm thick and 0.58 cm high. The housing is formed by two halves 2 and 3, which run along a to the longitudinal extent of the housing are fitted to each other parallel line and by means of two screws 4 and associated Nuts 5 are held together. Each housing part is rectangular in the lower section 6 in side and end views and in the upper section 7 it has a semicircular flange 7, which is a continuation of the side wall each housing half is. The semicircular space between the two flanges 7 takes the upper halves a rotary knob 8 and a coaxially arranged driven disk or a carrier 1o of the same diameter · The driven disk and the rotary knob are on the circumference provided with flanges 12 and 13 which protrude with their free ends in semicircular grooves 11 in the housing halves. A scale is attached to the outside of the circumference 12 of the carrier and the circumferential surface 13 of the rotary knob is corrugated and stands slightly above the circumference of the wearer, so that this knob 8 can be easily operated by means of the thumb or a finger is rotatable.

In the following, the housing half 2 is referred to as “rotary knob housing ^M in order to distinguish it from the other housing part 3.

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The inner wall of the rotary knob housing 2 has two annular grooves 14 and 15, both of which are rectangular in cross section are. On the outside of the rotary knob housing there is a mark 19 in the form of an arrow on the flange 7.

Within the flange 13 of the knob 8 has a plastic disc, one surface of which is flat and with the Knob housing 2 is engaged and a coaxial Drive shaft 16, which protrudes in the middle against the cover 3. The inner section 17 of the drive shaft is on the outside a toothing is provided, while the outer portion 18 of the shaft 16 is cylindrical and in an opening 2o stands which - forming a bearing for the shaft 16 is formed centrally in the driven disk 1o.

An externally toothed hub 21 is on the Seheibe 1o the flange 12 opposite side formed. The opening 2o is arranged centrally in the hub 21 and is arcuate Segment 22 on the surface of the hub has no teeth. Radially outside of segment 22 and immediately a projection 23 is provided within the flange 12, which has two opposite ends forms spaced stops.

The rotary knob 8 and the driven disk 1o are mechanically connected by a gear wheel 24 which is rotatably mounted in the lower part of the housing 1 about an axis parallel to the axis of the drive shaft . This gear wheel 24 is shown in FIGS. It has an outer peripheral part 25 provided with gear teeth, the teeth of which mesh with the gear teeth on the inner cable 17 of the shaft 16, as well as a hub 26 provided with external teeth, the teeth of which mesh with those teeth which correspond to the "'

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BATHROOM OHFSINAL

Comb teeth on hub 21 of the driven pulley. Achsatummel-27 are integrally formed on the gear wheel, which are freely rotatable in bearings formed by recesses on a partition plate 28. The plate 28 is essentially rectangular in shape in the lower area and is on the hand between the housing halves 2 and 3 pinched. The upper half of the plate, which is designed in the shape of a semicircle, lies between the projecting paddles 12 and 13 of the disc 1o or the rotary knob 8. In the center of the plate 28 there is a circular opening 3o, in which the hub 21 lies with the gear teeth of the disc 1o. A Z-shaped bent bracket 31 is. Means of spot welding attached to the lower half of the plate 28 around the central opening 3o and its free end 32 runs in Arc spaced around the edge of the lower half of the Opening 3o (see Figure 4). There is a recess in the arm 32

33 formed and aligned with it a similar recess

34 in opening 3o. The distance between the arm 32 and the plate 28 is selected so that the transmission gear 24 can be attached between these parts with shafts 27 mounted in the recesses 33 and 34.

A coupling spring 35 is held on the side of the plate opposite the bracket 31. This spring consists of thin Phoaphorbronaedraht the middle section of which forms a finger 36, which in turn is arranged in an expressed section 37 of the plate 28 in the manner shown in Figure 3 and is soldered there. The two end .abschnitt "de · wire form G-ftjrmig curved Federamre 38 and surrounded 3Θ ^1, which opposite sides of the hub 21 and! usually stand at a distance. The ends of the arms 38 and 38 are away from the plane of the plate 28.

166531Θ

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bent to form two Naaen 4o, which lie in the path of movement of the projection 23, which on the disk 1o is trained.

Within the disc 12, two thin and short pegs 41 are provided in diametrically opposite positions, which assign to the housing half 3. Against the surface with pin 41 of the disk 1o an electrically conductive contact disk. 43 made of phosphor bronze, which has two openings 44 through which the pins 41 protrude. The pins are used to hold the contact disk 43 in Position and the disc 43 is held with a press fit. The ends of the pins are used to hold the contact disc firmly 43 on the driven pulley 1o is provided with heads formed by heat and pressure. The contact disc 43 shows three sjjjh arc-shaped extending for making contact Customer contacts 451 46 and 47, which come from the disk 43 are pushed out and extend obliquely to the plane in the direction of the housing half 3. The two strips 45 and 46 are arranged on the same circle but point in opposite directions, while the third contact tire 47 has larger dimensions and is attached to the from

Its edge of the contact disk 43 is formed. So that it lies at a distance within the flange 12 and opposite a resistance element forming a circle 48, which is held in a circular channel 5o, which in turn is in the inner wall of the housing part 3 is formed, as Figure 4 clearly shows. The free ends of the contact strips are hook-shaped and thus form contact surfaces that are gold-plated,

The Wideratanda element 48 also consists of Wideratanda wire arranged at a slight mutual spacing. who on a «

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thick insulating plastic sleeve are wound, which in turn is mounted on a copper rod. These Copper rod is not all over into the shape of one 36o ° curved circular ring. A conductive wire is attached to each end of the resistor element 48, which is characterized by the plastic material from which the Housing half 3 is cast extending through its underside and each form a connecting lug 52. The two lugs 52 connected to opposite ends of the resistance element are aligned with one another and with a central one Flag 53, which also extends through the molded material extending through the housing half 3, and on its inner end is soldered to removal ring 54, which is in an inner section 39 of an annular channel 49, this channel has a stepped cross-section and is molded into the housing half at such a point is that the ring with the two in opposite directions facing contact strips 45 and 46 of the contact disc 48 is engaged. The three flags are cast in when the housing half 3 is cast.

In the housing half 3 bores are provided which are aligned with the corresponding bores in the housing half 2, to pass through bolts 4 to connect the two housing halves. There are also two on the housing half 3 Guide pins 57 made of steel are provided, which facilitate the assembly of the potentiometer by inserting them into corresponding bores 58 are guided, which are provided in the plate 28 and the other housing half 2 »

The knob 8, the gear wheel 24 and the driven pulley 1o are made of nylon, which is a self-lubricating Material is. The gear ratios of the gearbox are

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chosen so that ten turns of the rotary knob 8 a rotation of 3oo ° of the driven disk 1o comes. In this way, the position of the contact strip 47 on the resistance element 8 with a previously unachievable Accuracy can be set. The exact position of the contact strip can also be found on the basis of the scale and the mark 47 on the resistance element 48 recognize.

The potentiometer is assembled in the following way: The resistance element 48 and the ring 54 are in the corresponding Recesses are inserted in the housing half 3 and fastened in the operating position, in particular glued. the Contact disk 43 is pressed onto the driven disk so that the two pins that can be deformed by means of heat 41 stand through the bores 44 and the protruding ends of the pegs are then closed by the application of heat and pressure deformed to form heads which hold the contact disk 43 firmly on the driven disk. Then the driven disk so attached to the housing half that the free edge of its flange 12 in the groove 11 in the housing half 3 sits and the contact strips 45, 46 and 47 with the ring 54 and the resistance element 48 in engagement stand. ,

After the bracket 31 and the clutch spring 35 have been attached to the dividing plate 28, the gear wheel 24 is inserted into the two recesses 33 and 32. Then the driven disk is rotated until the segment 22 without teeth of the hub 21 faces the teeth on the hub 26 and then the plate 28 is carefully pressed in so that the guide pins 57 go through the bores 58 in the plate and the hub 21 through the opening 3o.

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So that the teeth on the hub overlap the hub 21, the driven disk Io must be turned against the stop, by engaging the Yorsprungs 23 with a the pin 44 of the spring arms 38 arises. The associated arm 38 is resilient so that the one formed without teeth Segment 22 can come into a position opposite the hub of the gear transmission, which then falls into its operating position. As soon as the rotating force is then driven by the Disk 1o is removed, it is immediately due to the resiliently bent arm 38 at a small angle twisted, which is so large that the toothed section is in meshing engagement with the teeth on the hub of the gear wheel comes.

The rotary knob 8 is then brought into position so that the front part of the shaft 16 fits into the recess 2o in the hub, which forms a bearing for the shaft 'and the teeth on the section 17 of the shaft 16 with the teeth 25 of the G- gear wheel 24 mesh. Then the housing half 2 is placed on the knob by inserting the guide pins 57 into the bores 56 and the screws 4 are inserted through the corresponding bores in the housing halves 2 and 3 and the nuts 5 are screwed onto their protruding ends.

To set the potentiometer, the rotary knob 8 is turned and its movement is transmitted via the gear wheel 24 to the driven disk 1o, so that - the contact strip 47 is moved over an arc over the resistance element 48 , which is equal to a tenth of the angle of rotation dee Rotary knob θ. The two contact strips 45 and 46 which are in singular contact with the planar Hing 54 form parallel paths from the contact strip 47 to the Hing

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i .. »iii .. '· ^ * i ^; .i. - 'i ._....- * i »■ Bad

54 »so that the contact resistance is negligibly small is. Because of the two contact strips 45 touching the ring 54 and pointing in opposite directions and 46 is the electrical resistance measured at a certain point after turning the rotary knob 8 into a Direction to a certain position just as great as if the electrical resistance were measured when the Knob 8 would be moved in the other direction in the same position.

When the contact strip 47 reaches the ends of its path at the Resistance element 48 is reached, then a slip clutch comes into effect, so that a further rotation of the Turning knob in the same direction cannot damage the parts. This is advantageous because because with a 1o: 1 reduction, there is no damage to the Parts of the potentiometer could occur if normal stops to limit the rotary movement of the driven Disc would be used.

This slip clutch works as follows: When the driven disk reaches the end of its rotational movement in one of the böideii directions, an end surface of the projection 23 comes into engagement with one of the outwardly bent pins on the spring arms 38 and causes the spring arm to engage resiliently With the circumference of the hub 21 provided with gear teeth, when the spring arm 38 touches the hub, the extension 4o prevents further rotation of the driven disk in the same direction and at the same time one end of the segment 22 of the hub 21 that has remained without teeth comes into a position opposite the toothed hub of the gear wheel 24 This further rotation d turning knob β in the same direction turns the gear

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gear 24, but the rotary motion is not transmitted to the driven pulley because the toothed one Hub 26 no longer meshes with the part of the honeycomb 21 provided with teeth. As soon as the turning knob 8 Force is removed, the resiliently bent spring arm 38 bends back out of engagement with the hub 22 and the outwardly facing approach 4o causes by pressing on the approach or projection 23 that the driven Disc rotates a small angle in the opposite direction so that the gear toothed one Section of the hub 21 brought back into meshing engagement with the toothed hub on the transmission gear will.

The invention thus creates - like the exemplary embodiment described shows - a potentiometer of extremely small dimensions, which can nevertheless be set very precisely can.

Of course, the invention cannot be applied to potentiometers in the manner described above, but also with adjustable resistances. In this case, one of the flags 52 and the slip clutch are omitted. The outward facing surface of the flange on the driven pulley is then in units of resistance calibrated between the flags 52 and 53 and the rotary knob is equipped with a device for fine adjustment or fine reading, e.g. a vernier. That way you can get the Read the resistance between the flags very carefully. In such a case the slip clutch should be left off so that the fine reading device and the resistance calibration remain synchronous with each other. It goes without saying that in this one Then fall on the hub 21 the entire circumference with teeth

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provided and in most cases the provision of stops is unnecessary since the driven pulley is unlimited rotate in any direction.

All details shown are important for the invention,

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Claims (7)

PATENT CLAIMS 1. Manually adjustable electrical resistance, in particular a potentiometer, in which the one between the connection lugs Resistance can be changed by relative rotation of an arcuate resistance element and an electrical pickup is characterized with a reduction gear between the rotatable part and a handle by a rotary knob (8), the circumference of which is essentially parallel to the plane of movement of the movable part lies. 2. Electrical resistor according to claim 1, characterized in that that the movable part (43, 1o) and the rotary knob (8) are arranged coaxially to one another and -in one of these parts a central recess (2o) is provided, which is the rotatable mounting of one of the other of the two Parts protruding shaft (16, 18) is used. 3. Resistor according to claim 1 or 2, characterized daduroh, that with the movable part (43) a disk (1o) with a cylindrical planach (12) is connected, on which a Scale is attached and the next to the manually operable Part of the rotary knob (8) runs. 4 · Resistor according to one or more of the preceding claims characterized in that in the center of the rotary knob (8) is provided with gear teeth (17) on its circumference Stub shaft (16) protrudes and that with these gear teeth (17) one. free-floating gear (25) meshes which drthfeet with another gear (26) of smaller size is connected, welohea in turn in meshing engagement 009884/0734 ateilt with a gear, which is designed as a hub (21) and rotatably with the rotatable part of the variable resistor connected is. 5. Resistor according to claim 4 »characterized in that a segment (22) on the hub (21) has no teeth. 6. Resistor according to one or more of the preceding claims, characterized * by a slip clutch (38, 4o, 21) / between the gear and the rotatable part of the resistor is switched. 7. ' Resistor according to one or more of the preceding claims, characterized in that the movable part of the resistor has a rotatable conductor designed as a plate, which has a sliding contact (47) for engagement with the arc-shaped resistance element (48) and two with the same radius on one Lying diameter and facing in opposite directions contact arms (45, 46) which extend out of the plane of the plate on one side thereof and are in engagement with a fixed slip ring. J00988A / 073A Blank page