Abstract:
A multi-position rotary switch whose handle is rotatable to a selected position to actuate a circuit for an electrically controlled device utilizing a magnetic sensor to initiate the actuating signal without any direct contact of traditional mechanical parts that suffer wear during repetitive operations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Research and development of this invention and application have not been federally sponsored, and no rights are given under any Federal program. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the operation of large off-highway vehicles such as moving trucks, long haul trucks, mining trucks and dump trucks employing tires, for example, as large as feet tall, in general, and to a diesel electric motor operation utilized to control the wheels of such vehicles into forward, reverse and neutral manners of movement. 
     2. Description of the Related Art 
     With such vehicles frequently being used 24 hour/day, 7 days/week, reliable switch regulation is critical. Whether the switch control be located on a dashboard of a vehicle or alongside the driver&#39;s seat, anything less than long-time performance of the switch can result not only in an added cost of replacement, but in the more important taking of the vehicle off-line while a replacement switch is obtained and set to proper use. As will be appreciated by those skilled in the art, a usual control for this is one available from the General Electric Company as an SBM switch employing traditional electro-mechanical components. Although used for many years, such switches are characteristically known to wear from physical contact requiring regular replacement, yet their implementation still continues today. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention, therefore, to provide a 3-position switch able to actuate a circuit for the electronic control of these type wheels in forward, reverse, and neutral modes without using the electro-mechanical components which typify the prior art. 
     It is an object of the invention, also, to provide such a multi-position rotary switch available for future usage in providing more than the 3-standard positions available for these forward-reverse-neutral electro-haul vehicle implementations. 
     It is another object of the invention to provide a multi-position rotary switch which is substantially free of physical contact in its operation so as to thereby extend the life of the switch in its intended applications of use. 
     It is a further object of the invention to provide a multi-position rotary switch of this nature that will be competitive in price with the electro-mechanical rotary switches presently employed for these wheel controls in truck, rail or like industrial equipment. 
     It is yet another object of the invention to provide this switch for more general applications requiring a large number of repetitive operations with positive positioning on each operation. 
     SUMMARY OF THE INVENTION 
     As will be appreciated, multi-position rotary switch devices for vehicular uses are each coupled with a relay to conduct the required control voltage to the vehicle&#39;s transmission. Accordingly, the multi-position rotary switch of the invention utilizes a magnetic sensor to initiate the control without any direct contact of parts that could suffer from wear. As such, the switch will also be quite useful in the steel mill, petroleum, chemical plant and similar heavy industries where thousands of operations with positive positioning are required per week. 
     Although “reed-type” magnetic switches are utilized in a preferred embodiment of the invention, it will be understood that they are just common names for switches that are actuated magnetically and are normally open-circuited in usage. As set forth in the description that follows, this preferred embodiment employs a “cam” with eight lobes designed to index at 45° positions, along with spring loaded followers to provide a positive indent at each selected position location. For the “forward”, “reverse”, and “neutral” positions for an indicated rear wheel usage, 3 such “reed switches” are utilized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of the invention will be more clearly understood from a consideration of the following description, taken in connection with the accompanying drawings, in which: 
         FIG. 1  is a side view of a multi-position magnetic rotary switch constructed in accordance with the teachings of the present invention; 
         FIG. 2  is a top view of a 3-position magnetic rotary switch according to the invention; 
         FIG. 3  is a front view of the multi-position magnetic rotary switch of  FIG. 2 ; 
         FIG. 4  is a rear view of the multi-position magnetic rotary switch of  FIG. 3 ; and 
         FIGS. 5 ,  5   a ,  5   b ,  5   c  and  5   d  are views helpful in an understanding of the “reed-type” magnetic switch and “cam” operation to actuate the levers and contacts in coupling the electrical voltages to the corresponding relays or similar devices in energizing the contractors to operate the electric motors in the drive wheels at the rear of a vehicle being driven. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the drawings for a 3-position rotary switch, a handle  10  is grasped and rotated to a selected position at 45° increments P 1 , P 2  P 3  ( FIGS. 5   a ,  5   b  and  5   c ). The handle  10  is journalled or attached to a shaft  11  with a profile (preferably “square”) at one end that synchronizes the movement of the handle  10  with a spring loaded cam  29  of 8 lobe configuration at an opposite end ( FIG. 5   d ). Such synchronized movement positions an arm  19  carrying a small magnet  33  into an orientation to close an internal circuit in one of three reed-type proximity switches  20  ( FIGS. 1 and 2 ) in creating a circuit that is connected to a control or pilot device to send the electrical signal required for the various operations of the electric truck, rail or other industrial equipment in use. As will be appreciated, the top view of  FIG. 2  shows three such proximity switches  20  with connections to such equipment by wire pairs of output conductors shown at  100 ,  101  and  102 . (The side view of  FIG. 1  shows one such switch  20  with its output conductor wire pair at  23 .) 
     In operation, the arm  19  with the magnet  33  attached follows the movement of the handle  10  and in each P 1 , P 2  and P 3  position shown in  FIGS. 5   a ,  5   b  and  5   c  locates the magnet  33  over one of the three reed magnetic switches  20  causing the closure of the circuit for that position. Such circuit then closes a relay by means of the wires  100 ,  101 ,  102  attached to each individual switch to allow the electrical signal impulse to couple to the corresponding rear wheel or other equipment controls. (In this respect, and for a 3-position rotary switch for controlling the rear wheels of a large off-highway vehicle, for example, the P 1  position may be selected for the “forward” movement of the wheels, the P 2  position for “neutral”, and the P 3  position for “reverse”.) 
     As further shown in  FIGS. 1 ,  2  and  5 , the 3-position rotary shaft is rigidly secured vertically using two sets of spacers at the bottom  15  (a large back spacer), and  17  (a front spacer), along with a reed switch mount plate  16  connected together by a tie bolt  14  to a metal mount plate  12 . A top frame plate  22  shown in  FIGS. 1  and (in phantom in  FIG. 2 ) is securely anchored to the front and rear plates  24  with machine screws. A stop collar  21  prevents the shaft  11  from moving out of position horizontally while maintaining the prescribed distance between the arm  19  and the proximity switch  20 . Such stop collar  21  is adjustable by a loosening to slide and control the gap between the arm and the switch, preferably over a distance 0.1 to 0.5 inch in the operating range recommended by the manufacturer of the proximity switch employed. In usage, the collar  21  is positioned so as to insure the operation of the assembly with respect to the framework dimensions of the rotary switch. 
     A front stop finger  18  shown in  FIGS. 1 ,  2  and  5  is keyed to the shaft  11  in providing both lateral (left-to-right) position as well as a defining stop for the extreme positions determined by the number of indexes or positions used. On either side of the finger  18 , a large thick washer is employed joined by a pair of small screws to prevent turning of the handle  10  any further than the 45° increments of  FIGS. 5   a ,  5   b  and  5   c , with the “neutral” position being that shown at P 2 . Such screw positioning, shown at  34  and  35  in  FIGS. 5   a - 5   c , serves to allow the lobes of the cam  29  to index at the 45° desired position. A follower  31  and spring  30  on a rear frame support  27  serve to provide a positive indent for the lobes of the cam  29  at each selected position. The spring load on the follower serves to indent a male part of the follower into a female lobe of the cam (as at  50  in  FIG. 5   d ) to index its positioning and to simultaneously provide the required tension to prevent its free running. Although not shown as such, it will be understood that within the follower  31  is a roller mechanism that matches to the contour of the lobe indent in the cam. The end result that follows is that turning of the handle  10  overcomes the tension of the spring  30  so that when the next handle position is reached, the spring  30  forces the follower  31  into the 45° position in providing the orientation for the alignment to the switch. A pivot shaft as to this is shown at  32  in  FIG. 2 . 
     In construction, knurled screws  36  hold the magnetic arm  19  onto the preferably square shaft  11  in actuating the selected one of the 3 reed switches to be brought into play. The switches, being normally open circuit devices, come into play in being “closed” when the magnet  33  is in position. A rear sleeve spacer  28  secures the alignment of the cam  29  against undesired movement as might interfere with the operation of the follower  31 , to hold the can position laterally. The tie rod  14  holds everything together, with the spacers being of a metal fabrication. When encased in a heavy duty polymer housing  13 , and closed at the back with a rear cover  25 , the rotary switch of the invention can then be secured with a large rear cover screw  26  ( FIG. 1 ). 
     Recognizing that a further implementation of an assembly might itself include the relay to connect to the control or pilot device in sending its electrical signals for various operations of equipment of the types by switch handle positionings, the advantage of the magnetic rotary device of the invention avoids the susceptibility of the electro-mechanical constructions which were susceptible to erroneous errors through physical contact wearings that caused its contacts to drift apart. Besides the contacts and followers having a tendency to wear out very easily, such movements undesirably varied the contact gap openings leading to further inconsistent operation and frequent needs to replace the contact tips. Quality issues were always present, with a concomitant suffering of operational longevity. With the invention as described above, the need for complex mechanical cam actions that were previously required to actuate the numbers of levers and contacts employed was significantly overcome, as shown by product testings. The end result is a simpler, more reliable, and longer lasting rotary switch for vehicular wheel and like equipment controls. 
     While there has been described what is considered to be a preferred embodiment of the present invention, it will readily be appreciated by those skilled in the art that modifications can be made without departing from the scope of the teachings herein. Thus, for example, while a 3-lobe cam could be utilized with the magnetic rotating switch of the invention, particularly for a panel mounting utilization of a cam with additional lobes would allow additional handle adjustments to an operator requiring further adjustment regulation of the vehicle or equipment. A 4-stage switch, or a 5-stage switch could be had in similar manner, as might find usefulness in various locomotive train applications. All that would there be needed then, is the connection of additional reed-type magnetic switch components and interconnections to provide the function desired. Essentially, then, for the 8 lobe cam  29  of  FIGS. 1-5  affording angularly positional lobe cuts of 45°, rotations are provided to allow up to 8 handle positions through a 360° rotation for utilizing a like number of magnetic reed switch interconnections in controlling electrically operated wheels, relays, motors and equipment by transferring their needed currents and voltages. For at least such reason, therefore, and for a 3, 4, 5, etc. lobe cam of a like number of angularly spaced positional lobe cuts, resort should be had to the claims appended hereto for a true understanding of the scope of the invention.