Exercise device
This application is a continuation of International Application No. PCT/DE90/00246, having an international filing date of Mar. 27, 1990 and designating the United States, which application is now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to an exercise device having a frame consisting of four pivotably interconnected parts. The lower frame part is mounted via a joint between its front and rear end, and the front frame part is pivotably connected to a stand. The upper frame part carries a saddle and the front frame part carries bundles. Pedals are attached to the lower frame, and the movement of one frame part in relation to another frame part or the stand is transferrable via a connecting rod and a crank to a drive wheel pivotably connected to the frame, thus driving a fly-wheel by way of transmission. 
     Such a device has been described in applicant&#39;s U.S. Pat. No. 4,371,185 and also in Applicant&#39;s German Patent Application No. P 31 13 242. 
     All devices of this kind known up to now have the disadvantage of forming different rotating angles of the drive wheel during the two phases of the reciprocal up and down movement of the frame. Because the frame consists of four joints, the different rotating angles of the drive wheel lead to different, physiologically disadvantageous accelerations of saddle, handles and pedals. 
     The different rotating angles of the drive wheel which occur during the two phases of movement result from the fact that the rotating movement of the lower frame part leads to a relative movement of the crankshaft bearing in relation to the stationary connecting rod bearing. 
     Another disadvantage of current devices of this kind is the fact that there is no possibility of integrating all rotating and swinging parts of the gear, especially connecting rod and cranks, into the gear casing in order to protect the user of the device against injuries. 
     SUMMARY OF THE INVENTION 
     The overall objective of the present invention is to provide a therapeutic and sports device which provides better harmony of movements during the two phases of the cycle and improved protection of the user against injury. 
     The objective of the invention is accomplished a lower frame part consisting of two parallel adjusted support struts having a crankshaft immovably connected to a drive wheel and pivotably mounted between the struts: a connecting rod is mounted to a (crankshaft throw) and is attached to a stand or fixed close to the point of equal angles between the two extreme positions of the lower frame part and the two dead centre positions of the connecting rod. 
     The above arrangement occurs when the distance between a crankshaft bearing and a line connecting the rotation axis of the lower frame part and the joint axis between lower and front frame part is approximately equal to, or equals the distance between a stationary connecting rod bearing axis attached to the stand and the rotation axis of the lower frame part and is equal to the distance between the connecting rod bearing axis attached to the stand and the line connecting the rotation axis and joint axis between lower and front frame part. 
     Thus, the phases of movement of the crankshaft with the drive wheel as well as the speeds and accelerations of saddle, handles and pedals in relation to the movement of the individual elements in both phases of movement--except for the reverse movement--become equal or are substantially equal to such an extent as to guarantee harmonic movements. 
     Given a common casing, this arrangement also allows the protection of all rotating parts and the connecting rod against outside contact. 
     Additionally, it allows the lower frame part, which turns into a two-armed lever because of the rotation joint, to support the crankshaft in front of or behind the rotation joint, according to constructive estimation. Accordingly, only the arrangement of the remaining gear elements needs to be changed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     There follows a detailed description of preferred embodiments of the present invention to be taken together with the accompanying drawings wherein: 
     FIG. 1 is a simplified schematic side elevational view of one embodiment of an exercising device made in accordance with the present invention, with certain parts removed for purposes of clarity, and 
     FIG. 2 is a simplified schematic side elevational view of only a portion of the exercising device, showing the parts in the two extreme end positions thereof. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, like elements are represented by like numerals throughout the several views. In FIG. 1, the frame 10 consists of an upper frame part 12, a lower frame part 14, a front frame part 16 and a rear frame part 18. The upper frame part 12 is connected to the front frame part 16 by means of a joint 20, and connected to the rear frame part 18 by means of a joint 22. The lower frame part 14 which is made of two support struts 74 (only one of which is visible in FIG. 1) is connected with the front frame part 16 by means of a joint 24 and with the rear frame part 18 by means of a joint 26. The entire frame 10 is carried by stand 28, whereas the lower frame part 14 is supported on stand 28 by means of a rotation bearing 30, whereas the front frame part 16 is supported on the stand by a joint 32, connecting it with rod 34 and another joint 36 on the lower part of rod 34. The upper frame part carries the saddle 38. Pedals 40 are attached to the lower frame part 14, whereas the front frame part 16 carries handles 42. 
     The lower frame part 14 carries the gear, consisting of the crankshaft 46 which is immovably connected to drive wheel 48, the crankshaft bearing 44, the connecting rod bearing 68, the transmission 52 as, the flywheel 60 the generator 64 and the connecting rod 70 with the stationary connecting rod bearing 72. Although the lower frame part is shown as carrying the crankshaft 46 in front of the rotation bearing 30, the gear can be arranged so that the crankshaft is carried behind rotation bearing 30. Drive wheel 48 is pivotably mounted between support struts 74 of lower part 14. A casing 76 protects all turnable parts of the gear as well as the connecting rod 70 against outside contact. 
     In order to provide harmony in movement among the parts of the device, the distance between X the stationary connecting rod bearing 72 and the line connecting rotation bearing 30 and joint axis 24 and the distance Y between rotation axis 30 and the stationary connecting rod bearing 72 are both approximately as large as the distance Z between crankshaft bearing 44 and the line connecting line rotation bearing 30 and joint axis 24. 
     FIG. 2 illustrates the lower portion and its connection to the stand, with the lower portion shown in solid lines in one of its end positions and in dotted lines in its other end position. The angle α between the two end positions of line 14 is approximately 35°. 
     The distance X between the stationary connecting rod bearing 72 and the straight line leading through the axes of rotation bearing 30 and joint 24, is approximately as long as the vertical distance Y between horizontal lines drawn through the axes of rotation bearing 30 and connecting rod bearing 72, and approximately as long as the distance Z between the axis of the crankshaft bearing 44 and the straight line leading through the axes of rotation bearing 30 and joint 24. 
     The two dead centre positions of connecting rod 70 now form an angle β which, according to the invention which is 35.8° is almost identical with angle α. 
     Minor differences in angle size of angles α and β up to a difference of approximately 10° results in slight disadvantages regarding harmony of movement of saddle, handles and pedals and can be tolerated if they are compensated for by major constructive and other advantages.