Flexible coupling
FIELD OF THE INVENTION 
     This invention relates to couplings for transmitting torque from one shaft to another, and in particular it relates to a flexible coupling. 
     BACKGROUND OF THE INVENTION 
     Couplings are traditionally divided into two types, rigid couplings and flexible couplings With rigid couplings the torque transmission occurs directly without any possibility of flexing or the like. Flexible couplings on the other hand are constructed to compensate for certain wavelength prolongations and irregularities of the torque. Articulated joint couplings which receive longitudinal movements, parallel movements and angular deviations of the shafts are in this category of flexible couplings. This category also includes torsion spring couplings which can compensate for rotary oscillations or torsional vibrations and torque thrusts. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a flexible coupling which is characterized by a simple construction which is relatively small in size (especially shorter in length) and which permits a large axial offset, a large radial offset as well as a large angular offset (of greater than 10°) as between the two shafts. With such an arrangement, the rotational stability of the coupling according to the invention can be adjusted as desired within a wide range in the construction (between high torque resistance and high rotational elasticity). Another object of the invention is to manufacture the flexible coupling as an all-steel coupling with as high as desired rotational elasticity. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     There follows a detailed description of two embodiments of the present invention which are described with reference to the accompanying drawings, wherein: 
     FIG. 1 is a side view, with the lower portion shown in central section, of a first embodiment of the invention, 
     FIG. 2 is a plan view of FIG. 1 which is turned 90° relative to the orientation of FIG. 1, 
     FIG. 3 is a central sectional view through a second embodiment of the present invention, and 
     FIG. 4 is a composite view of FIG. 3, the left hand portion being a plan view thereof and the right hand portion being a central horizontal sectional view thereof. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The flexible coupling shown in FIGS. 1 and 2 includes a pair of collars 1, 1&#39;, each of which has a pair of support axles 2, 3 or 2&#39;, 3&#39;, respectively. A pair of coupling arms 4, 5 are articulated on support axle 2, which coupling arms are also articulated at their outer ends with a pair of torque levers 6, 7, respectively. 
     In a corresponding manner, two coupling arms 8, 9 are mounted on support axle 3 and are articulated at their other ends with torque levers 10, 11. 
     Torque levers 6 and 10 are non-rotatably fastened to the two ends of a coupling rod 12. In a corresponding manner, the torque levers 7 and 11 are non-rotatably connected to the ends of a coupling rod 13. 
     The two coupling rods 12 and 13 are configured as torsion spring rods and are mounted rotatably in bearings 14, 15 or respectively 16, 17. 
     The aforementioned bearings 14 to 17 are arranged on the one side of an intermediate member 18 which is configured as a rectangular or quadratic plate or respectively are formed as one integral piece with this intermediate member. 
     The connection between the collar 1&#39; and the intermediate member 18 corresponds to the above described connection between the collar 1 and the intermediate member 18, and accordingly corresponding numerals have been used except that each numeral is changed by a prime mark (&#39;). 
     FIG. 2 more clearly illustrates that the coupling rods 12 and 13 associated with the collar 1 are arranged off center, i.e., spaced away from the axis of the collar 1 and symmetrical relative to the axis of the collar 1. In a corresponding manner, this is also true for the coupling rods 12&#39; and 13&#39; which are associated with the collar 1&#39;. 
     The two pairs of coupling rods 12, 13 and 12&#39;, 13&#39; are angularly offset relative to each other by 90°, each pair of coupling rods lying in a plane relative to the plane of the other pair, and located on different sides of the intermediate member 18. 
     The coupling of FIGS. 1 and 2 operates as follows. 
     The torque to be conveyed is split into tangential or circumferential forces which are transmitted from the coupling arms 4, 5, 8, 9, as traction and compression forces. If for example the effective torque is transmitted from collar 1 in the direction of arrow 19, then coupling arms 4 and 5 are moved in . the direction of arrow 20 and coupling arms 8 and 9 in the direction of arrow 21. Over the torque levers 6 and 10 or respectively 7 and 11, the coupling rods 12 and 13 are also loaded with torque. The two other coupling rods 12, 13, function in the same way. The desired rotational elasticity of the coupling is attained as a result of the torsional stresses on the two pair of coupling rods. 
     If an axial thrust of collar 1 occurs relative to collar 1&#39; (for example, in the direction of arrow 22), then torque levers 6, 7, 10 and 11 are drawn somewhat inward over coupling arms 4, 5, 8, 9 (in the direction of arrow 23). Coupling rods 12, 13 are then rotated slightly in the opposite direction in their bearings 14, 15 or 16, 17, respectively. In this manner a considerable axial movement of the two collars 1, 1&#39; relative to each other is possible. 
     If collar 1 is moved radially (for instance in the direction of arrow 24) relative to collar 1&#39;, then coupling rods 12, 13 are rotated (over coupling arms 4, 5, 8, 9 and torque levers 6, 7, 10 and 11) in the same direction in their bearings. 
     It is apparent that as a result of the arrangement of the two pairs of coupling rods 12, 13, 12&#39;, 13&#39;, offset 90° from each other, radial movements of the two collars 1, 1&#39; can be made in the desired directions. 
     An observation of FIGS. 1 and 2 will reveal that with the coupling according to the present invention angular displacements between the two collars 1 and 1&#39;, even of considerable size, are possible (over 10°). If for instance collar 1 is tilted so that the axis of support axle 2 in FIG. 2 is moved to a position above the viewing plane of FIG. 2 and the axis of support axle 3 below the viewing plane, then as a result of this, torque lever 6, 7, 10 and 11 are moved somewhat inward, which results in an opposing rotation of the coupling rods 12, 13. 
     FIGS. 3 and 4 illustrate another embodiment of the present invention. In this embodiment, the same structural components which cooperate with one another are referred to by the same reference numerals as used in FIGS. 1 and 2. 
     In FIGS. 3 and 4 the coupling rods 12 and 13 are mounted rotatably in bearings, (for example 14a, 15a) of the two collars 1 and 1&#39;. 
     The coupling arms, (for example 4, 5) associated with the different coupling rods (for example 12, 13) of the same pair of coupling rods are in this embodiment connected over support axles 2a or respectively 2b, 2c, 2d, which are mounted tightly on the outside of the intermediate member 18a, which is annular in this case, or respectively are configured as an integral piece with this intermediate member 18a. 
     As in the embodiment of FIGS. 1 and 2, the torque levers 6, 7, 10 and 11 are connected non-rotatably with the ends of the coupling rods 12, 13. 
     The articulation connection joints between the coupling arms 4, 5, 8, 9 and the torque lever 6, 7, 10 and 11 occurs, as in the embodiment of FIGS. 1 and 2, over joint pins or flexible stay bolts 25. 
     In the embodiment of FIGS. 3 and 4, the intermediate member 18a, which is configured as a ring, is connected to pairs of coupling arms, for example 4, 5, at four peripheral points which are offset from each other by 90° over the above mentioned support axles 2a, 2b, 2c and 2d. 
     The operation of the embodiment of FIGS. 3 and 4 corresponds to the operation of the embodiment of FIGS. 1 and 2 which has already been described. 
     Although the invention has been described with respect to a preferred embodiment, it will be apparent that the invention is capable of numerous modifications and variations, apparent to those skilled in the art, without departing from the spirit and scope of the invention, as defined in the claims.