Abstract:
An adjustable hydrostatic control system that adjusts in length to locate mutual neutral locations while transmitting the necessary torque through mating sliding spines.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates generally to agricultural windrowers, and more particularly to an easily adjustable control system for the hydrostatic drive system of a self-propelled mower conditioner having ground drive wheels.  
         [0002]     The general mode of operation of a modem windrower is to have tandem hydrostatic pumps, one for each of two drive wheels, each pump having a depending pintle arm such that forward and reverse movement of the pintle arm relative to a neutral position causes the associated hydrostatic pump, and thus the associated drive wheel, to rotate. During the original assembly of the windrower and during normal maintenance and repair operations in the life of the machine, the pintle arms must be adjusted to neutral. In the machine just described, the adjustment is made at a location under the cab, requiring disassembly of several other components to establish access.  
         [0003]     It would be a distinct advantage to reduce the difficulty of making the neutral adjustment, while providing full operation of the steering control and speed of the hydrostatic drive system of the windrower.  
       SUMMARY OF THE INVENTION  
       [0004]     Accordingly, it is an object of the present invention to provide a simple and convenient neutral adjustment mechanism for hydrostatic drive system of a windrower.  
         [0005]     Another object of the present invention is to provide an adjustable steering control shaft for a windrower.  
         [0006]     It is another object of the present invention to provide an adjustable and simple steering control shaft for the pintle arms of tandem hydrostatic pumps.  
         [0007]     Yet another object of the present invention is to provide a telescoping splined steering control shaft that can be adjusted in length and still transmit the required torque through the splines.  
         [0008]     Yet another object of the present invention is to provide a steering control shaft that can be adjusted in length without affecting the steering pto.  
         [0009]     It is yet another object of the present invention to provide an adjustable steering control shaft that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use.  
         [0010]     It is a still further object of the present invention to provide an adjustable control system for the hydrostatic drive of a windrower.  
         [0011]     These and other objects are attained by providing an adjustable hydrostatic control system that adjusts in length to locate mutual neutral locations while transmitting the necessary torque through mating sliding spines.  
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]     The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:  
         [0013]      FIG. 1  is a side view of a windrower of the type with which the adjustable control system will prove advantageous;  
         [0014]      FIG. 2  is an partial left side view of the control system of the instant invention;  
         [0015]      FIG. 3  is a partial schematic exploded view of the length adjustment assembly of the instant invention; and  
         [0016]      FIG. 4  is a partial schematic view of the assembled adjustment assembly. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “left” or “right” are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already by widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail.  
         [0018]      FIG. 1  shows the two primary components of a self-propelled windrower  10 , i.e., tractor  12  and header  14 . Tractor  12  has a main frame  16 , with a longitudinal horizontal axis from front to back, that is supported by a pair of drive wheels  18  (only one shown) on the forward portion thereof and a pair of rear wheels  20  adjacent the rear end. An engine, located under cowling  24 , a transmission and other components, as will be discussed further below and generally well known in the art, are likewise supported on the main frame  16  and provide the power necessary for the machine to operate. A cab  26  encloses the operator&#39;s platform to provide an environmentally controlled location from which the windrower may be comfortably operated.  
         [0019]     Header  14  may be of several designs, typically comprising a cutting mechanism, either a sicklebar or rotary cutter, a feeder mechanism and conditioning rolls. The header is supported by a hydraulic lift and flotation structure  28  that may be activated to selectively raise or lower the header between transport and operational positions.  
         [0020]     Referring now to  FIG. 2 , the hydrostatic control system is shown to include a conventional steering wheel  40  and console  42  inside the operator&#39;s cab  26 . The cab would, of course, include additional components (not shown) such as a seat, electrical and mechanical controls for operation of the windrower, an air conditioning unit, and the like. The steering wheel is attached to a stub shaft  44  that is connected to the upper end of front shaft  46  by a universal connector (not shown). The universal connector is well known in the art as a mechanism to transmit rotational movement between two shafts that are not necessarily in axial alignment. The lower end of front shaft  46  is connected to elongate bottom shaft  50  by another universal connector, or power-take-off shaft,  48 . As will be discussed further below, a length adjustment assembly  80  is attached to the rear most end of bottom shaft  50 , at a location rearward of and below cab  26  in an accessible position.  
         [0021]     Length adjustment assembly  80  is connected, by another universal connector  82 , to elongate threaded rod-like member  84 —one end with right-hand threads and the other with left-hand threads—, such that any turn of steering wheel  40  results in a proportional turn of member  84 . Two tandem hydraulic pumps  86 ,  88  are located above member  84  and each has a pintle arm  90 ,  92 , respectively, depending therefrom. Each pintle arm has an internally threaded block threaded onto member  84 , such that rotation of the rod causes the pintle arm to move either forwardly or rearwardly, depending upon the direction of rotation of member  84 . Thus, rotation of member  84  results in one pintle arm rotating in a clockwise direction and the other rotating in a counter-clockwise direction, when viewed from the side, as in  FIG. 2 . This causes one pump to increase flow and the other to decrease flow, turning the windrower. Engine  94  supplies power to the hydraulic pumps.  
         [0022]     Within cab  26  is a forward-neutral-reverse lever  100 . This is continuously and selectively movable to allow a change in speed in either the forward or reverse directions. The neutral position has either an indent or other mechanism to allow easy recognition by the operator. Lever  100  is intended to selectively move member  84  forwardly or rearwardly to simultaneously move both pintle arms an equal amount, thus allowing an equal increase or decrease in flow from the hydraulic pumps. In this embodiment, lever  100  moves the lower end of rigid connecting member  102  forwardly or rearwardly. A sliding connector  104  is affixed to the end of connecting member  102  and has an opening therein through which shaft  50  extends and rotates without interference. A pair of small plates  106 ,  102  are affixed to shaft  50 , rotate therewith, and spaced very closely to connector  104 , such that movement of connecting member  102  causes connector  104  to engage one or the other plates  106 ,  108  to move shaft  50  and member  84  forwardly or rearwardly to adjust the speed of the windrower.  
         [0023]      FIG. 3  shows the length adjustment assembly  80  to be comprised of three basic components, a male spline shaft  100  affixed to the end portion of bottom shaft  50 —shaft  50  including an outside threaded portion  113 —, a female internally splined shaft  114 —having an externally threaded portion  116 —, and a tubular member  118  with internally threaded portions  120 .  121 . A universal connector  82  is affixed to the outer end of the female splined shaft  114  for connection to threaded shaft  84  to accommodate for a small amount of axial misalignment.  FIG. 4  shows the assembled adjustment assembly  80  to include a pair of jam nuts  97 ,  98  one threaded onto the threaded portion  113  of male splined shaft  100  and the other threaded onto the threaded portion  116  of female splined shaft  114 . To adjust the length of mechanism  80 , i.e., the amount of insertion of the male splined shaft into the female splined shaft, the jam nuts  97 ,  98  are loosened and the splined shafts either rotated clockwise or counterclockwise to adjust the length of mechanism  80 . When the desired length is obtained, the jam nuts  97 ,  98  are tightened against tubular member  118  to hold the components in a rigid unit.  
         [0024]     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the inventions. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.