Abstract:
A manually operated angle pickup or detector has a rotatably mounted and manually movable transmitter element, a sensor that scans the transmitter element and a detent coupling that operates magnetically and in a contactless manner to maintain the transmitter element in defined angular positions which can change from one to another by manual operation. The detent coupling includes at least one permanent magnet with poles disposed in the axial direction and two toothed disks provided on the side of at least one pole of the permanent magnet. The two toothed disks are radially spaced and have a corresponding number of teeth. The disks are interconnected by the magnetic flux and are of a material with good conductivity.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a manually operated angle pickup or detector having a rotatably mounted and manually movable transmitter element, a sensor scanning the transmitter element and a magnetic coupling releasably holding the transmitter element in selected angular positions. 
     BACKGROUND OF THE INVENTION 
     In a known angle detector disclosed in DE 43 11 496 C2, the transmitter element is a disk. The disk exterior margin or border area is formed by tongues that are bent in such a manner that they engage along a part of their length in a cylindrical surface concentric to the rotary axis of the transmitter element. Concentric to this cylindrical surface and at quite a small radial spacing therefrom, north and south poles of a magnet associated with the second part of the detent mechanism are provided, one after the other in sequence around its periphery. 
     One disadvantage of that arrangement is that, with predetermined spacing and dimensions, it is of certain very small dimensions which are predetermined in absolute terms on the basis of the pole spacing required. 
     DE 44 36 724 A1 discloses another electronic position detector having a magnetic detent system in which the magnetic detent device includes at least three radially grooved magnet detent disks coaxial to one another and alternatively wave- and carrier-resistant. The disks are in turn radially grooved over the entire disk periphery. 
     One disadvantage of this construction is that the attraction force between the individual magnetic detent disks is decreased by axial displacement. Thus, only slight tolerances are acceptable in its manufacture. 
     SUMMARY OF THE INVENTION 
     Objects of the present invention are to provide a manually operated angle detector having a magnetic detent coupling for releasably holding its transmitter element in selected angular positions, while allowing a small structure, and relative to that small structure, allowing extensive built-in tolerances, without being negatively influenced in its operation. 
     The foregoing objects are basically attained by a manually operated angle detector, comprising a rotatably mounted and manually movable transmitter element, a sensor scanning the transmitter element, and a magnetic detent coupling releasably holding the transmitter element in selected angular positions after being manually moved between selected ones of the angular positions. The detent coupling includes at least one permanent magnet and first and second toothed disks of material that conducts magnetic flux. The permanent magnet has first and second poles arranged in axial alignment. The first toothed disk is on a side of the permanent magnet adjacent the first pole and has a number of teeth. The second toothed disk has the same number of teeth and is radially spaced from the first toothed disk. The first and second toothed disks are coupled by magnetic flux. 
     The axial arrangement of the north and south poles facilitates miniaturization, especially in its radial direction. Thus, the diameter of the angle detector is independent of the very slight distances between the poles. 
     It is especially cost-saving to use one single permanent magnet. No mounting or assembly error or deviation because of incorrect construction can then occur with this configuration. 
     Sprocket wheels or toothed disks are especially suitable for miniaturization, and can be arranged on both sides of the permanent magnet. Such disks are connected with one another by a tube. Thus, the toothed disks, the corresponding disks and their connection element are of a material which is a good conductor of the magnetic flux. As a result of the differing contours of the teeth, the air gap between toothed disks and corresponding disks varies. The magnetic flux, and thus, the attraction of the teeth of the toothed disks and corresponding disks is at the greatest when the teeth lie directly opposite one another. 
     Both poles can be connected with one single toothed disk, whereby the corresponding disks are arranged at some radial spacing therefrom. However it is also possible that only one of the two poles is connected with a toothed disk, and only one corresponding disk is provided at some radial distance therefrom. Opposite the other pole and at some axial distance therefrom, a toothless disk is arranged, which toothless disk remains in magnetically conductive connection through a connection element. The toothless disk can be a separate structural part or can be constructed integral with the connection element as some sort of cup of one piece. 
     The quantity of one hundred teeth facilitates especially good manipulation of the angle detector for rapid and precise adjustment or input, for example of coordinates in the case of computerized numerical control (CNC). Other preferred numbers of teeth are sixteen, thirty-two, fifty or sixty, but the number of teeth should lie in the range of ten to one hundred sixty, to guarantee good manipulation and handling. 
     The angle detector is especially compact when the detent mechanism is provided directly in the adjustment or presetting disk. 
    
    
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
     FIG. 1 is a side elevational view in section of a manually operated angle detector according to a first embodiment of the present invention; 
     FIG. 2 is a bottom plan view in section of the angle detector taken along line II—II of FIG. 1; 
     FIG. 3 is a side elevational view in section of a manually operated angle detector according to a second embodiment of the present invention; and 
     FIG. 4 is a side elevational view in section of a manually operate angle detector according to a third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a manually operated angle detector  1  with an adjustment or presetting disk or adjusting wheel  3 . Adjusting wheel  3  is introduced from the exterior by means of a shaft  5 , and is mounted in a housing  7 . Altogether, the rotatably mounted parts rotated by means of shaft  5  are indicated in their entirety as transmitter element  8 . Housing  7  has a housing cover  9  and a cup-shaped bottom portion  11 . Housing cover  9  projects with formation of an axially symmetric flange  13  to the side, outwardly over bottom part  11 . With the aid of flange  13 , angle detector  1  can, for example, be mounted in a panel, switchboard or keyboard. 
     Within housing interior chamber  15 , housing cover  9  has a discoid or plate-like reinforcement  17 . The exterior contour of reinforcement  17  corresponds essentially to the configuration of the opening of bottom part  11 . On its other side, housing cover  9  has another discoid or plate-shaped reinforcement  19 . In the middle of housing cover  9 , a perpendicular passage borehole  21  extends through the reinforcements  17  and  19 . Shaft  5  is mounted in borehole  21  and is retained radially and axially by means of bearings  23  and  25 . 
     The exterior  29  of a tube  27  forms a cylindrical extension of the exterior contour of reinforcement  19 . On the interior  31  of tube  27 , two disks  33  and  35  are arranged at some axial distance from one another with corresponding interior teeth  37  and  39  without angular displacement. 
     On the end  41  of shaft  5  projecting out of housing  7 , an axially symmetrical part  43  is mounted, for example, by shrinking on or gluing on. At its periphery, part  43  supports a permanent magnet  45  and two identical toothed disks  47  and  49  with exterior toothing/sprocket arrangements or teeth  51  and  53 . The first toothed disk  47  is arranged on the permanent magnet side turned toward or adjacent housing  7 . The second toothed disk  49  is arranged on the side of permanent magnet  45  turned away or remote from housing  7 , without angle displacement relative to first toothed disk  47 . The degree of spacing between the two toothed disks  47  and  49  corresponds to the thickness of permanent magnet  45  and also determines the degree of spacing between the two toothed disks  33  and  35 , which in turn are arranged concentrically around the toothed disks  47  and  49 . Between the crown line of the interior toothing/sprocket arrangements  37 ,  39  of disks  33 ,  35  and the exterior toothing/sprocket arrangements  51 ,  53  of toothed disks  47 ,  49  in turn exists a small radial spacing. 
     The number of teeth on toothed disks  47  and  49  corresponds to the number of teeth present on the interior toothing/sprocket arrangements  37  and  39  of disks  33  and  35 . Thus, the number of teeth of toothed disks  47  and  49  and disks  33  and  35  can be selected as desired, but having the number of teeth being one hundred is especially desirable. For simplified illustration, only  16  teeth are shown in FIG.  2 . 
     Toothed disks  47  and  49 , disks  33  and  35  and tube  27  are formed of a material which is a good conductor of the magnetic flux from the permanent magnet  45 . 
     Permanent magnet  45  together with toothed disks  47  and  49 , disks  33  and  35  and tube  27  form a detent mechanism. Thus, permanent magnet  45  along with toothed disks  47  and  49  represent a sort of horseshoe magnet, and disks  33  and  35  with tube  27  represent a sort of magnet yoke. The magnetic flux is attracted proportionally more strongly the smaller the degree of radial spacing (i.e., the dimensions of the air gap between disk  33  and toothed disk  47  and/or between disk  35  and toothed disk  49 ). This radial spacing is the smallest when the teeth of disks  33 ,  35  and toothed disks  47 ,  49 , respectively, lie directly opposite one another. Because of the plurality of magnetic circuits, corresponding to the number of teeth of disks  33 ,  35  and toothed disks  47 ,  49 , the attraction force between the entirety of the horseshoe magnets and the magnet yoke in the setting shown in FIG. 2 is relatively strong, causing a high degree of attraction, even when the detent factor of the individual magnetic circuits is low. 
     At the end  55  of shaft  5  located in the interior chamber  15  of the housing, a round code disk  57  is mounted. For enlargement of the contact surface between code disk  57  and shaft  5 , a ring  59  is arranged at end  55  concentric to shaft  5 . The ring, together with end  55 , forms a flat surface on its side turned toward code disk  57 . 
     On reinforcement  17  in housing interior chamber  15  a bifurcated bracket  61  with a cutout  63  is mounted. The margin of code disk  57  projects into this cutout  63 . A light enclosure can be provided in bracket  61  to serve as a sensor which produces a pulse-like signal with each rotation of shaft  5  into each subsequent detent position. When the sensor produces a pulse-like signal, angle detector  1  can also be used as incremental position detector and transmitter. On the bottom of bracket  61  a conductor plate  65  is arranged. Plate  65 , by means of an inserted chip, may convert the measurement results of the scanning, and thus, determine a corresponding angle setting of toothed disks  47  and  49  relative to stationary disks  33  and  35 . Alternatively, the scanning signals could be conducted further to an external evaluation arrangement. 
     The parts projecting out of housing  7  are covered by means of a hood-like part  67  of the setting or adjusting wheel  3  mounted on the side of the part  43  exterior to housing  7 . This hood-like part  67  simultaneously controls the rotation of the parts connected with the shaft, and along with that, the manual position setting. 
     FIG. 3 shows a second manually operated angle detector  101 , having a construction essentially identical with that of the first embodiment. The difference between the first and second embodiments resides in that the permanent magnet  145  is connected not with the shaft  105 , but rather is connected with the housing  107 . Also, the toothed disks  147  and  149  are stationary, whereas the disks  133  and  135  are connected with the adjustment or presetting wheel  103 . The detent mechanism operates as in the first embodiment. However, the moving and stationary parts are interchanged. 
     The third embodiment of an angle detector  201 , illustrated in FIG. 4, is essentially identical with the first and second embodiments. The permanent magnet  245  is connected with the housing  207 , and is connected at the south pole with a toothed disk  247 . This toothed disk  247  is arranged at some radial distance from a corresponding disk  235  with a corresponding number of teeth, that in turn is connected with the adjustment or presetting disk  203 . Opposite the north pole a toothless disk  233  is arranged with some axial spacing. Toothless disk  233  is connected through a tubular connection element  227  with the disk  235  corresponding to toothed disk  247  in magnetically conductive connection, whereupon the magnetic flux is closed. Toothless disks  233  and tubular connection element  227  are constructed of one piece in this embodiment, and thus, have the form of a cap. 
     The angle setting can be scanned by means of a modified arrangement of the embodiment exterior to housing  7  or  107  and within the hood-like part  67 . One of the toothed disks  47 ,  49  or disks  133 ,  135 ,  235  can be used for this purpose. 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.