Control Lever With Automatic Return to Original Position

The invention is related to control units, preferably for a radio control, which, when manually operated, will automatically return to an original position. More particularly, a control lever detects at least one predetermined position of at least one rotatable shaft.

Previously known devices of this type are often very complicated and also very bulky as to their construction and therefore are not conducive for use as a control lever in a miniaturized form are used in industry, especially to control travelling cranes and the like. Such radio control units are normally supported on the belt of the operator fastened around his waist.

Therefore, it is an object of the invention to provide a device of the type mentioned above, by which the radio control unit is small and compact, and also reliable, robust and easily controlled.

The above-mentioned objects are achieved according to the invention by a device comprising an arm, one end of which is mounted on a shaft so that the arm is rotated about its mounted end upon rotation of the shaft, when the shaft is rotated under the influence of a control lever, and with the arm arranged to abut against one of two adjacent profiled parts which resiliently moved against stop means which stop means are provided in the unactivated original position of the arm, with the profiled parts so formed that when reaching a predetermined position a snap effect can be manually sensed by the control lever.

The invention is to be described in more detail with reference to the accompanying drawings in which

FIG. 1 is a side elevational view of the control lever of the present invention, as for example in a radio control unit;

FIG. 2 is a partial section along line II--II of FIG. 1;

FIG. 3 is a view of a part of the mechanism of FIG. 1 without the use of torsion springs; and

FIG. 4 is a modified embodiment of the part of the mechanism shown in FIG. 3.

With reference to FIG. 1, a control lever 1, preferably for a radio control unit, is shown. As further shown in FIG. 2, two shafts 2, 3 held in a support device, are rotatable in either direction by means of control lever 1. The projecting ends of shafts 2, 3 are provided in the same plane and substantially normal to each other. Each of shafts 2, 3 has an arm 4 fastened to one of its ends. On the opposite end of arm 4, facing toward the direction of the shaft 2 or 3, there is attached a roll 5, which, with the control unit in an original position, the roll 5 abuts against consisting of a helical spring 9 and two torsion springs 11, 12 are so arranged that they press end 6 of arm 4, which has roll 5 attached thereto, and the profiled parts against parts 7, 8 are furnished with steps 13, 14 respectively. Upon rotation of shafts 2, 3 by control lever 1, steps 13, 14 form markings for predetermined positions which can be sensed manually by the control lever 1. The steps 13, 14 are so formed that rotation of shafts 2, 3, can return arm 4 to an original position by means of springs 9, and 11, 13, as shown in FIG. 1.

A stop 15 is provided between profiled parts 7, 8 so that the profiled parts 7, 8 will abut stop 15 when they are in the original position. When one of the profiled parts is activated by roll 5 on arm 4, the other profiled part, not activated by roll 5, abuts stop 15, and in doing so, provides a strain in helical spring 9 and in torsion spring 11 or 12 with the activated profiled part. Due to the use of two different springs being used, a helical spring and torsional springs, double security against spring breakage is obtained and also return of the actuated profile part of the original or O-position is made more secure, when control lever 1 is unloaded.

In FIG. 3, an embodiment of the device according to the invention is shown in which torsion springs 11 and 12, which have been shown in FIG. 1, are omitted. Parts 7, 8 are rotatable around bearing pins 16. Shafts 2, 3 have ends 17.

In FIG. 4, a modified embodiment of the invention is shown in which the profiled parts 18, 19 are journalled on a pin 20. The upper ends of the profile parts are loaded towards each other by means of a helical spring 9. A torsion spring 21 is placed on the pin 20 and the outer ends of the legs of the torsion spring are situated on the outside of the profiled parts to further load the profiled parts towards each other. Hence, here also a double security against spring breakage is achieved. The spring 9 and 21 are arranged to bring the profiled parts 18, 19 to abut against stops 22 and 23, and moreover to return the arm 4, which is arranged on one of the ends 17 of said shafts 2, 3, to the original position (O-position).

On the free ends of said shafts 2, 3, different types of position indicating switch means can be placed, as e.g. reversing switches, potentiometers or optoelectrical systems.