Shaft coupler
This invention relates generally to means for attaching the shafts of a horse drawn vehicle to the harness of the horse, and particularly to a quick coupling and release device for use in connection with the shafts of a sulky used in harness horse racing. 
     The method used for coupling the shafts of a harness racing sulky to the harness of the horse, prior to this invention, consisted of suspending the shafts a short distance behind their free ends from the backband of the harness by two straps attached laterally, and buckled to specialized loops which encircle the shafts. Fixation of the shaft to the harness is then accomplished by a &#34;safety strap&#34; which encircles one shaft fore and aft of the loop, and buckles back on itself then follows the girth to the opposite shaft, where similar wrapping and buckling is repeated, while applying tension. 
     This method has many disadvantages, which may be listed as follows: 
     (a) The free end of each shaft extends a substantial length beyond its fixation point to the harness, making the shafts unnecessarily longer, at times creating difficulties to the itinerant nature of horse racing. 
     (b) Furthermore, this extra entension creates a lethal hazard during collisions. 
     (c) During training and warm-up periods, the sulky is hitched an unhitched frequently. It is obvious, from the above description that this procedure consumes a great deal of valuable time and labor. 
     (d) During an accident, where the horse is in a recumbent position, it becomes very important to release the animal as quickly as possible, so that its life can be saved, or from becoming seriously impaired. 
     (e) The above mentioned shaft extensions also signficantly interfere with the freedom of movement. 
     It is, therefore, the primary object of this invention to eliminate the above hazards and disadvantages. 
     This is accomplished by this invention by providing a quick shaft hitch-up and release mechanism which also eliminates the need for a shaft extension, beyond the fixation point to the harness. 
    
    
     In describing the invention, reference will be made to the attached drawings in which: 
     FIG. 1 is a general view showing the location of the invention; 
     FIG. 2 is an elevation of the invention, and 
     FIG. 3 is a side view of FIG. 2. 
    
    
     In describing the drawings, the coupling 1 is shown consisting of an elongated rectangular main frame 2 having a buckle section at the upper end thereof, and a rectangular-shaped loop 4 at its bottom end. A rectangular plate 5 extends at right angles from the main frame 2 below the buckle part 3. Slightly above the bottom loop 4 is a clevis 6 formed by two spaced rectangular plates 7 and 8 which are identical to plate 5, and extend at right angles from the main frame 2. The remaining space 9 in the main frame 2 contains a spring 10 which is in compression between the underside of the plate extension 5 at its top, and a washer 11 which is attached to a latch pin 12, which is contained within the spring 10. 
     The pin 12 passes through a hole 13 in the plate 5, a hole 14 in plate 7, and a hole 15 in plate 8. The holes 13, 14, and 15, are properly lined up to allow the free passage of the pin 12, which under normal conditions is long enough to extend part way above the plate 5, and part way below the clevis plate 8. 
     The coupling device 1 is attached in the proper location on each side of the horse by means of the harness backband 16 and a connecting strap 17. 
     Each of the shafts 18, terminates at its free end into a centrally located, narrowed down end 19 which fits freely into the clevis 6. A hole 20 is provided in this narrowed down end 19 through which passes the pin 12 when the shaft 18 is fixed to the harness. For clarity purposes, the elaborate harness, which is not essential to the description of the invention, is eliminated from the drawings. 
     The attachment of the shaft to the harness is very simple and rapid, and consists of pulling the pin 12 out of the clevis 6, by means of a rope or cable 21, against the action of the spring 10; inserting the shaft end 19 into the clevis 6, and allowing the spring 10 to push the pin 12 to pass through the holes 14, 20, and 15. 
     The harmful shaft extension 22, which is shown in broken line in FIG. 1 is eliminated.