Crank driver

Abstract

To provide a crank drive to form a significantly oval circulatory path, in particular of a pedal 1a.SOLUTION: The crank drive periodically changes the effective lever length of a crank 2. In this invention, gear levers 4' or 7 are mounted on a crank 2 at both ends 2a, 2b. The gear levers 4' and 7 rotate in opposite directions with respect to one another thereby forming two further movement axes within the pedal path, and can be thus adapted to natural human leg movement in a force-saving and ergonomic manner.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a crank driver with periodically varying effective lever length, in particular to an oval-shaped force applicator path as described in the preamble of claim 1 and the associated arrangement. [Background technology]

[0002] Attempts have been made in the past to vary the effective lever length of a crank drive, thereby increasing the lever length used to apply force ("pedaling" on a bicycle) and thereby increasing torque. U.S. Patent No. 4,960,013 describes a bicycle with a telescopically extending crank arm. However, this configuration is quite complicated and prone to wear. Japanese Patent Publication No. 10-35573 describes a crank drive with a control system that changes the pedal path to an elliptical shape. It also shows a gear arrangement with three identical gears, but this appears to be very prone to wear and has an ergonomically unfavorable movement sequence for the cyclist due to the dead center of the elliptical pedal path. A more "oval" pedal path would be desirable, but such a solution is not yet known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 4,960,013 [Patent Document 2] Japanese Patent Application Publication No. 10-35573 Summary of the Invention [Problem to be solved by the invention]

[0004] The objective of this invention is to propose a crank drive that periodically changes the effective lever length, while being relatively small in size (and weight), and in particular, to provide a pedal (force application part) with an egg-shaped circular path that allows for sufficient and significant lever extension, and to make the "human-machine system" resemble almost natural walking or running using multi-axis motion. In particular, we provide a crank drive that significantly eliminates commonly occurring dead center areas and allows the exercise sequence to be adjusted to individual needs. In addition to these requirements, we also provide a crank drive that can be designed with a small volume occupation, reduced weight, stability, and robustness. We also propose an associated system, particularly a system for sports equipment, in which the crank drive creates a natural exercise sequence and / or improves efficiency. [Means for solving the problem]

[0005] The above object is achieved by a crank driver and a corresponding arrangement according to claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.

[0006] To achieve the above objectives, a gear lever is mounted on each crank on each side (of the bicycle). It preferably rotates via a gear drive, and when pedaling, the length of the effective crank as a whole (crank + gear lever) increases. The gear lever preferably comprises at least three spur gears with externally toothed spur gears. The three spur gears of the gear lever are journalled in a common housing, and the gears are periodically (when applying force) aligned approximately in the extension of the crank arm. The gear ratio (ratio of the number of teeth) is preferably 2:1:1. The arrangement with externally toothed gears reduces manufacturing costs and allows for a stable design. This results in a very compact gear arrangement, easy to accommodate, and in particular optimises lubrication and protection against the ingress of foreign matter. A similar configuration is possible with a chain or toothed belt, in which case the chain or toothed belt connects two sprockets (chain-wheel) or belt transmissions with a transmission ratio of 2:1 (note that in JP 10-35573 A it is 1:1), and the tensioning device is also preferably located inside the housing of the gear lever.

[0007] The gear lever design for bicycles, according to the present invention, consists of two movement elements. In the first movement element (Movement A), the gear lever is arranged at the outer free end of the crank. The large spur gear of the gear lever is non-rotatably connected to the crank's axle, which is usually where the pedals are attached. The force applicator, in particular the pedal, is non-rotatably connected to the outermost spur gear of the gear lever. In conjunction with the revolution of the crank driver (crank + gear lever), the force applicator causes the gear lever to rotate around the large spur gear. On the other hand, in the second movement element (Movement B), the gear lever is connected to the inner end of the crank, and the large spur gear of the gear lever is preferably non-rotatably fixed to the (bicycle) frame (or machine body), so that the gear lever rotates around the large spur gear in the opposite direction to the intended rotation of the crank. Here, the large spur gear is connected to the frame by a plug, a pressure connection, or a screw connection. To superimpose motions A and B, the gears' shapes must be precisely matched to ensure precise periodicity in the crank length change, so that motions A and B interact to produce the intended overall, approximately egg-shaped pedaling motion. The proposed crank drive is preferably offered as an aftermarket kit or a component for re-equipping bicycles. Its simplified design can also be used in various machines (e.g., energy conversion machines) to improve cost-effectiveness. For example, in wind or hydroelectric power generation, the crank can be designed as a kind of "wing." In this case, a gear lever resembling a swiveling control flap is provided at the outer end. This can significantly improve efficiency.

[0008] One robust, simple and unique design for the gear lever is achieved by arranging preferably three (or more) gears in a completely sealed enclosure between two flattened egg-shaped or flattened pear-shaped bearing housings. This ensures that the gears are well protected from dust and water and ensures optimal lubrication over a long period of time. Preferably, a multi-stage gear with counter-rotating stages inside the "thick" gear lever on the drive side (often realized as a chain) has a spur gear supported on the crankshaft, which is simply connected to a sprocket (chain wheel) (for the chain driving the rear wheel).

[0009] Further advantages will become apparent from the following description of a preferred embodiment based on conceptual drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a top view (partially in section) of a first embodiment of a crank driver as an element (motion A) when applied to a bicycle. [Figure 2] FIG. 2 is a side view of the crank driver of FIG. [Figure 3] FIG. 3 is a side view of a bicycle crank driver (with motion A) as it rotates through 360°. [Figure 4] FIG. 4 is a top view (partially in section) of a second embodiment of the crank driver as an element (motion B) when applied to a bicycle. [Figure 5] FIG. 5 is a side view of the left half of the crank driver of FIG. [Figure 6] FIG. 6 is a side view of the right half of the crank driver of FIG. [Figure 7] FIG. 7 shows a combination A+B of the first and second embodiments of the crank driver in a bicycle. [Figure 8] FIG. 8 is a side view of the overall motion of the combined first and second embodiments of the crank driver on a bicycle as it rotates through 360°. [Figure 9] FIG. 9 is a vertical cross-sectional view of the vicinity of the pedal. [Figure 10] FIG. 10 is a 3D perspective view of the crank driver. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1 and 2 conceptually illustrate one embodiment of a crank driver 1 according to the present invention, which includes a crank 2. For simplicity's sake, only the right crank with pedal 1a is shown here as the force transmission unit of the bicycle. In this preferred embodiment, the pedaling force F (see the right part of FIG. 3) of the cyclist acts via the crank driver 1 on a common axle 3a in the bicycle's bearing bracket 3 (see FIG. 4). The crank driver 1 can also be attached to a custom bicycle (e.g., a sleeper bicycle) or a rowing cart. The bearing bracket 3 is a similar concept to the central support or shaft support 3, and is therefore designated by the same reference numeral. The same applies to the axle 3a, which is indicated by a dashed line in FIG. 1. As already explained, bicycles typically have cranks 2 with pedals 1a offset by 180° (see FIGS. 4 and 7). In the first element (movement A) (see Figures 1 to 3), the outer free end 2b of the crank 2 is connected to the drive gear train 4, which is integrated into the gear lever 4', while in the second element (movement B) the arrangement is "inverted" (see Figures 4 to 7), i.e. the "inner" gear lever 7 and the drive gear train 4 integrated therein are arranged closer to the center (of the overall rotation of the crank drive) and the crank 2 is radially outward relative to the gear lever 7.

[0012] The gear lever drive train 4 of the present invention comprises at least three externally toothed spur gears 4a, 4b, and 4c. All gears are preferably mounted in a sealed housing 5 and rotate cycloidally (epicycloidally) alongside one another radially outside the larger gear 4a (or, rather than in a straight line, at an angle within the triangular housing, as shown in FIG. 8). In the gear lever, the spur gears 4a, 4b, and 4c mesh with one another (as shown in FIG. 2, they are positioned linearly from the drive gear train 4 to the crank 2). In "orbital" motion A, the pedal 1a, which moves in an orbit when the rider pedals, is rigidly fixed to the outer spur gear 4c, for example, via a formed column extension. The (large) spur gear 4a is fixed relative to the crank 2. It supports two roller bearings 6 on its two shoulders. The roller bearings 6 are arranged between the spur gear 4a and the housing 5. The bearings 6 are dimensioned to stabilize the force transfer between the crank 2 and the housing 5, while bearings 6 within the housing 5 can be made relatively small, taking into account the low stresses.

[0013] Both the left and right bearings 6 of the central spur gear 4b can be replaced by a single bearing, for example, a single needle bearing bushing. It should be noted that the other roller bearings 6 can also be replaced by other bearings. The drive gear train housing 5, which is pear-shaped when viewed from the side (see FIG. 2), preferably consists of two flattened, oval, or flat, elongated housing half-shells 5a, 5b. After the spur gears 4a, 4b, 4c are installed, the housing 5 can be closed, i.e., a sealed capsule for the drive gear train 4, by, for example, screwing, welding, soldering, adhesive, snap-fitting, or similar means. The housing half-shells 5a, 5b can be identical (mirror images) and stamped from sheet metal, for example, to reduce manufacturing costs and improve stability.

[0014] The encapsulation and the elongated shape of the drive gear train 4 allow this section to function as an additional crank for the crank 2, making the term "gear lever" 4' doubly appropriate. The spur gears 4a, 4b, and 4c can be angled or otherwise toothed instead of straight, optimizing the force transmission and smoothing the movement of the drive gear train. The intermediate spur gear 4b acts as a rotational direction reversal element, resulting in the motion sequence shown in Figure 3, which is described below. The preferred transmission ratio, i.e., the ratio of the number of teeth of the spur gears 4a, 4b, and 4c, is 2:1:1. When the crank 2 rotates 90° (around the axis 3a of the bearing bracket), the elongated gear lever 4' rotates an additional 90° (natural rotation) (around the gear 4a as the axis of rotation 4d'). As a result, for every 90° rotation of the crank 2, the angular orientation of the gear lever 4' rotates by 180° as a whole.

[0015] In Figure 3, the direction of travel of the bicycle is indicated by arrow V, and the dashed-dotted line N is the conventional pedal path (which is circular and results from the pedaling motion of the crank 2 as it rotates around the central bearing bracket 3). This 360° circular motion occurs clockwise here. At upper dead center OT (the so-called 0 o'clock or 12 o'clock position), the gear lever 4', which houses the drive gear train 4, is bent backward by approximately 90° at the upper end of the crank 2. Then, due to the gear meshing with a 2:1:1 ratio, at a rotation angle of 90° (3 o'clock position), it assumes the elongated configuration shown in Figure 2. In this configuration, the center distance between gears 4a and 4c of gear lever 4' is added to the length of crank 2, so the lever length of the segment A is maximized. This results in a circular motion path L for the force input at pedal 1a, which is slightly offset in the direction of travel V of the bicycle, and is depicted by the dotted line path. After another 90° rotation, the crank driver 1 reaches the bottom dead center UT, which corresponds to the 6 o'clock position. At this point, the gear lever 4' rotates another 180° (i.e., in the case of a bicycle, the pedal position shifts toward the rear wheel). During the reverse crank motion, from approximately 7 o'clock to approximately 11 o'clock, the gear lever 4', along with the pedal 1a, contracts radially inward, resulting in the circular motion path L being inside the circle N. This continuous change in the effective crank length of the crank driver 1 over a 360° rotation changes the effective crank length during motion A, thereby solving the problem of the present invention. A force F applied to the same pedal 1a generates a relatively increased rotational moment compared to the prior art pedal motion. The maximum effective lever length occurs at the 3 o'clock position on the right side of Figure 3. When the gear ratio is 2:1:1, shifting the position of the gear lever 4' backward by 90° (approximately at the 12 o'clock and 6 o'clock positions), and the center distance between the spur gears 4a and 4c creates a relatively large offset, the dead point becomes "inconspicuous" (the effective angle between the crank 2 and the gear lever 4' is only about 14° at most for a standard crank length of 175 mm), which, particularly for bicycles, is an ergonomically preferable tread path and brings the force application range into what would traditionally be the dead point area.The significantly larger effective crank of the crank driver compared to a conventional crank driver during force application (maximum at 3 o'clock) and pedaling down significantly increases torque and, consequently, power output. From 6 o'clock through 9 o'clock to 12 o'clock (top dead center OT), the circular motion path L is shifted toward the driving or travel direction, resulting in a somewhat shorter pedal path N than the conventional pedal path N. The increase in effective crank length of crank 2 in the region of maximum possible force (approximately 3 o'clock) results in significantly higher torque and power output (compared to the conventional pedal path N) for a nearly constant pedal path and the same total force over the new circular motion path L. The significantly shorter crank in the significantly more passive region (approximately 7 to 11 o'clock) can be advantageously utilized, for example, when "turning a windmill into the wind." On the other hand, the 3 o'clock position, which corresponds to the force direction arrow F, is the maximum crank length and therefore the torque gain is available.

[0016] The gear lever 4' is pivoted approximately 90° backward (relative to the 12 o'clock position) on the axle 4a' (e.g., realized as a slotted axle). The angular offset can be adjusted by adjusting the pedal 1a (the pivot angle) to change the circular motion path L relative to the conventional pedal path N or the angle of the gear lever 4' pivoted on the pedal axle relative to the crank position. This allows for adapting the "pedal path" to the personal preferences of various users, as well as to various usage situations (sports facilities, urban areas, etc.) and pedaling frequencies. The magnitude of the angular offset (e.g., 22.5°) depends largely on the indexing pitch of the slotted axle mentioned above and the coupling between the crank 2 and the gear lever 4'. For example, a larger number of teeth allows for more precise adjustment. The first element (motion A) of the crank drive 1 of the present invention can be easily adjusted to suit the individual cyclist's needs with minimal expenditure. The fact that fine adjustment is possible when the number of teeth is large also applies to adjusting the inclination of the pedal 1a in accordance with the number of teeth of the grooved shaft 4d.

[0017] Figure 4 and the accompanying Figures 5 and 6 illustrate the second element (movement B) of the crank drive 1. The additional gear lever 7 is constructed similarly to the previously described gear lever 4', except for the modifications specifically described. In the first embodiment (Figures 1 to 3), the gear lever 4' is located outside the outer end 2b of the crank 2 and rotates together with the crank 2 during pedaling (i.e., it rotates around the center of the spur gear 4a fixed to the outer end 2b of the crank). In contrast, in the second embodiment, the large gear 4a is fixed (via an intermediate bushing) to the bicycle frame 10 so as not to rotate, more precisely to the central axle or bearing bracket 3. On the drive side (usually with a gear for the chain or belt to the rear wheel), a multi-stage gear lever 7 is preferably provided (see Figure 4). A sprocket 8 for connecting the chain to the rear wheel is fixed to the multi-stage gear lever 7 with a screw 9. In addition to the three gears 4a, 4b, and 4c of the gear lever 4 already described, the multi-stage gear lever 7 also includes additional gears 4a', 4b', and 4c' arranged opposite to them (disposed in line toward the bearing bracket 3 or frame 10) to form the preferred counter-rotating stage. Here, the spur gear 4a' is mounted via an intermediate bushing (see FIG. 9) on the extension of the axis of the spur gear 4a facing the bearing bracket 3, and a sprocket 8 is fixed to the spur gear 4a' (first gear). The counter-rotating stage is thus created so that a chain can be conventionally driven via a sprocket fixed to the gear 4a', which rotates forward despite the reverse revolution of the gear lever 7. If a different transmission ratio is desired for the chain or belt drive, the gear lever 7 can be removed and the (front) sprocket 8 can also be easily replaced (see FIGS. 4 or 9).

[0018] On the non-drive side (without chain) (left side in FIG. 4, see also FIG. 5), a gear lever 4' configured similarly to FIG. 2 is sufficient for attachment to the bearing bracket 3. Here, the inner spur gear 4a is again fixed relative to the frame 10 (as on the right side). On the other hand, the outer spur gear 4c has its axis non-rotatably connected to the inner end 2a of the crank 2, preferably with an adjustably connected grooved axle toothing. To the free end 2b of the crank 2, a pedal 1a is fixed, also in a known manner, as shown in FIG. 6. Here, the pedal 1a can be a conventional one that rotates freely, as is usual for bicycles. However, it can also be arranged in a track according to FIGS. 1 to 3. In that case, the pedal alignment direction is adjustable (the inclination can be preset in accordance with the grooved axle toothing 4d).

[0019] In Figures 4 (and 5), the spur gears 4a, 4b, and 4c of the gear levers 4' and 7 are shown meshing at a speed ratio of 2:1:1. The meshing of the gears is indicated by the cross-hatched sections between the gears: spur gears 4a and 4b mesh, and spur gears 4b and 4c mesh. As in Figure 1, the spur gears of the gear lever 4' on the left side of Figure 4 are supported in a housing 5 consisting of housing half-shells 5a and 5b with corresponding roller bearings 6. This half-shell structure can also be used for the gear lever 7 on the right side of Figure 4 (which differs from gear lever 4' by having an additional speed ratio and a counter-rotation stage) (see also Figures 7 and 9). Instead of the sprocket 8 secured by a screw bolt to the transverse frame 10, a toothed belt can also be used to drive the rear wheel.

[0020] When pedal 1a is depressed, crank 2 rotates, and spur gears 4b and 4c of gear lever 4' mesh with each other and rotate around the larger spur gear 4a within housing 5. The same applies to spur gears 4a, 4b, and 4c of "thick" gear lever 7 (which has spur gears 4a', 4b', and 4c' as a second gear train to reverse the direction of rotation). Here, spur gear 4a has twice as many teeth as spur gear 4b (as the intermediate gear) and spur gear 4c (as the coupling gear to crank 2). This allows for further periodic variation of the effective crank length of the crank 2 and gear levers 4' and 7 as a whole. This embodiment, with the gear lever centralized, is advantageous for adapting to the familiar pedal height at the conventional dead center (6 o'clock and 12 o'clock positions) corresponding to pedal trajectory N (see Figures 3 and 8). In this case, the length of the crank 2 is increased by a length (approximately equal to) the distance between the centers of the large spur gear 4a and the spur gear 4c on the outside of the gear lever 4'. By lengthening the crank using connection A+B (central arrangement B, in which the gear lever is located in the center, and track arrangement A, in which the gear lever is located on the pedal side of the crank), the dead center area in the track that would otherwise be almost unused can be used as an area for transmitting force. If connection A+B is not used and only one of them is applied, the angle offset (based on the 12 o'clock position) will be adjusted within the limit of the spread between the gear lever 4' or 7 and the crank 2. In embodiments with a gear lever located at the inner crank end 2a, a long crank 2 relative to the central gear lever 4' or 7 rotates the central gear lever 4' or 7 in a counter-rotational motion proportional to the overall crank motion (i.e., when pedal 1a is depressed, crank 2 rotates the inner gear lever 4' or 7 in a counter-rotational direction proportional to the rotation of crank 2). At dead center OT (pedal position 12 o'clock), gear lever 4' or 7 is positioned opposite crank 2 and parallel to crank 2 at 3 o'clock, resulting in a double crank length increase (the center distance between gears 4a and 4c on center gear lever 4' plus the amount of crank length increase). This centered gear lever embodiment significantly increases the crank length, as desired, both when pushing down on the pedals and when each pedal is pushing up.By utilizing a foot fixation system (clip-on shoe, pedal shoe, or similar) on pedal 1a, this centering can be utilized to increase torque even during the so-called ascending phase of the pedal. Because the overall pedal path is unusually long (compared to the conventional pedal path N), depending on the crank extension, this new path L (which periodically lengthens the crank when applying force) results in a significant increase in torque due to the unusually long path of the force-applying part (pedal) when applying the same force. This, in turn (usually two cranks on a bicycle), results in a higher combined power output from both cranks as they rotate, as shown in detail in Figure 8.

[0021] Figure 5 is a side view of the left part of Figure 4, i.e., the non-drive side (the side without the sprocket). The pedal circular motion path L, more specifically the maximum achievable position, the eccentricity of the path, and the position (relative to the horizontal) of the pedal path resulting from the central positioning of the gear lever 4' or 7, can be easily and individually adjusted, for example, by adjusting the alignment at the dead center OT between the (outer) crank 2 and the gear lever 4' or 7 (of the central bearing bracket 3) (which is essentially always ahead of the opposite position of the crank and gear lever), for example, by using the teeth of the grooved axle 4d. In Figure 5, the alignment of the crank 2 "bent" so that it leads the long housing 5 of the gear lever 4' by 22.5° at the dead center (12 o'clock position) is shown. If desired, the crank 2 can also be "bent" to a more appropriate angle by extending the gear lever 4' or 7, or by adjusting the angle in addition to the alignment of the 4d tooth of the slotted shaft. As mentioned above, this angle of bend is highly dependent on the tooth pitch of the spur gear leading to the crank 2. In this example, this tooth pitch is preferably 32 teeth, but it can be greater to more precisely vary the angle of bend. This "bent" also affects the most efficient crank position, which can be "moved" from, for example, the 3 o'clock position (in FIG. 3) toward the 2 o'clock position. This allows for a variety of applications and ergonomics of the crank driver 1. From another point of view, as a further additional variation of the pedal circular motion path L, a connection is made (Figs. 7, 8, 10) in which a gear lever 4' is also attached to the outer crank end 2b of the crank 2, which gear lever 4' is suitable for being rigidly (i.e. without a complete drive gear train 4 and therefore without rotating about the spur gear axis) and at a certain adjustment angle to a conventional (free-spinning) pedal as an extension of the crank.

[0022] Figure 6 shows a side view of the drive side with the gear lever 7 shown on the right side of Figure 4, which has an octagonal appearance but is preferably arranged in a flattened oval shape (Figure 9) to provide a counter-rotation stage. For this purpose, a larger spur gear 4c' with the same number of teeth as the immovable spur gear 4a is arranged in the gear plane facing the frame 10. The crank 2 is preferably detachably connected (by press, plug-in, or screw connection) to the spur gear 4c via an intermediate bushing. Here, the spur gear 4c carries the larger spur gear 4c' in its inner gear plane. The spur gear 4c' meshes with the spur gear 4a' via a smaller connecting gear 4b' (the spur gear 4a' has the same number of teeth as the spur gear 4a and is therefore congruent and overlapping in the side view). With this gear arrangement and the selected ratios for spur gears 4a, 4b, 4c and 4a', 4b', 4c', the sprocket connected to spur gear 4a' by bolt 9 (see FIG. 4) is guaranteed to rotate in the same direction as crank 2 (as in a conventional bicycle), even when gear lever 4' or 7 is operating in the opposite direction to rotate crank 2. This counter-rotation mechanism is of independent importance (independent claim 5) and is inventive in its own right. In FIG. 6, as in FIG. 5, the outer crank 2 is shown angled relative to the central gear lever 7 (and also 4') in relation to the alignment of gear lever 7. This "bending," as with the non-drive side (FIG. 4), can be individually adjusted to change the position of maximum efficiency (e.g., the 3 o'clock position). This results in an increased section of maximum torque, and significantly changes the circular motion path L (see FIGS. 3 and 8) and its position relative to the horizontal. The angular position adjustment between the crank 2 and the centrally located gear levers 4' and 7 can also be adjusted in a similar manner as described in conjunction with the track system that secures the gear levers to the outer crank end 2b of the crank 2, minimizing the conventional dead center intervals and allowing for individual adjustment to utilize what were dead centers for applying forces.

[0023] FIG. 7 shows a particularly effective combination of two embodiments (arrangement of the gear levers on the central and raceway sides of the crank 2). In particular, the crank 2 bent in a zigzag pattern towards the bicycle (towards the bicycle frame 10) is intended to create the smallest possible transverse pedal distance (Q factor). Here, the inner side of the outer crank end 2b facing the frame 10 moves in approximately the same plane of rotation as the inner crank end 2a, or in a plane slightly closer to the frame. Each crank 2 is at least partially formed as a cylindrical hollow body (see FIG. 10), which completely or partially encloses the bearing seat for the half shell 5a or 5b and the extension of the spur gear 4a, 4a', 4c. This allows the outer raceway teeth The lever causes the outer contour of crank 2 to protrude slightly.

[0024] In principle, however, the crank 2 may be of conventional design. Furthermore, instead of the drive with spur gears 4a, 4b, 4c, a chain or belt drive 4f can be used, which is additionally designated by a reference number in the gear lever 4'. Similarly, for the gear lever 7, the sprocket or belt wheel is designated by the reference number 4g on the same axis (in particular towards the outer gear wheel of the counter-rotating stage). In this way, the gear drive and the chain drive can be coupled together in the gear lever 7 in order to reverse the direction of rotation of the drive sprocket 8.

[0025] Figure 8 shows the oval pedal path with a crank drive (consisting of a gear lever 4' mounted on the central crank end and a gear lever 7 mounted on the distal crank end, as shown in Figure 7), alongside a conventional pedal trajectory N according to the prior art (see Figure 3). The gear lever 4', which is fixed to the outer end of the crank, is designed oval in Figure 8, and the gear train 4a, 4b, 4c (or also the belt drive 4f) is arranged curved rather than linearly. As is clear from comparison with the circular movement trajectory L (with only one gear lever set, as shown in Figure 3), the double gear lever arrangement with a central gear lever at the inner crank end 2a and an orbital gear lever at the outer crank end 2b results in an additional crank extension (roughly speaking, from the 2 o'clock to 3 o'clock position, where it is desired to apply a large force to the pedal 1a). Nevertheless, the overall crank length is minimized in the passive section (around the 9 o'clock position) where pedaling is not possible. This reduces dead-point areas, resulting in an ergonomically favorable motion and optimal power generation. It should be emphasized that the pedal surface tilts (relative to the horizontal) during the transition from the 6 o'clock to the 9 o'clock position, and then tilts in the opposite direction during the transition from the 12 o'clock to the 3 o'clock position. This results in an optimal adjustment of the force application (adjustment of the direction of the cyclist's foot force). Specifically, if the outermost edge of pedal 1a is oriented to the upper right, i.e., the 2 o'clock position, then the pedal surface is perpendicular to the cyclist's foot extension movement in this position (see force F on the pedal top surface in Figure 8, the pedal surface is perpendicular to it). During the transition to the 3 o'clock position, the gearing forces rotate pedal 1a toward the horizontal, thus providing the optimal direction for the cyclist to apply force when pushing down.

[0026] This motion sequence is also suitable for use in wind turbines or water wheels. In that case, the crank 2 (or possibly the orbital gear lever 4') would have a corresponding profile for its blades. For example, if the wind (designated W in Figure 8) is blowing from the upper left, particularly high power output would be achieved at the 2 and 3 o'clock positions, because the crank length would be maximized at those positions. On the other hand, in the headwind section (the left half of Figure 8), relative energy savings would be achieved (by minimizing the crank arm length and by proper alignment, as well as adjusting the pedal face angle). Figure 9 is a longitudinal cross-sectional view showing how the gear lever 7 is attached to the central bearing bracket 3. As in Figures 6 and 7, the crank 2, shown here on the right, meshes with the spur gear 4c with its face teeth 4d. The intermediate gears 4b and 4b', such as those between 4a and 4c, shown in Figure 6, are not shown here for clarity. The large spur gear 4a is non-rotatably fixed to the bearing bracket 3 via a cylindrical extension and an intermediate bushing. The counter-rotating spur gear 4a' is rotatably mounted on the cylindrical extension and is guided towards the sprocket 8. The gear wheels 4a' and 4c' of the counter-rotating stage are identical in size and connected by an intermediate gear 4b' (shown in Figure 6) (the gear ratio is 1:1, while the gear ratio of the spur gears 4a, 4b, and 4c shown at the top is 2:1:1). This gear 4c' is connected to the same axis as the spur gear 4c and is firmly fixed in the half shells 5a and 5b via sealed bearings 6. This design allows the gear lever 7 to be easily attached to the bearing bracket 3 and is thin thanks to the bearing 6 having a radially inner recess in the tooth surface.

[0027] Figure 10 shows a 3D perspective view of the crank driver 1 with the crank 2 removed. The gear lever 4' (on the right) connected to the outer end of the crank and the wider gear lever 7 (on the left) connected to the inner end of the crank are positioned along the crank 2. The crank 2 is preferably made of a light metal by casting, while the housings of the orbital gear levers 4' and 7 are preferably made of plastic (particularly high-tensile polyimide or glass or carbon fiber). This allows for a streamlined profile and allows for easy conformance to the blade profile for wind and hydroelectric applications. The blade profile is shown in the figure as a dashed line toward the bottom of the crank 2 or a dashed line toward the top of the orbital gear lever 4'. Having a blade profile P is particularly effective when the gear lever 4' protrudes outward (see the 2 to 4 o'clock positions in Figure 8), while the opposite (the left half of Figure 8) provides a favorable low torque. The technical concept of the present invention can be used in various fields, such as propellers, ship propellers, turbine blades, and other lever-driven crank drives (e.g., conveyor systems, winding devices, agitators), as well as piston engines, steam engines, and the like, to achieve high torque, overcome the dead-center problem, improve starting characteristics, reduce noise generation, and reduce power requirements. This results in high power output, low fuel consumption, and reduced emissions (environmental protection). In particular, with regard to agitators, the tightly periodic change in crank length (the mixing blades can be similar to the blade profile P described above) allows for excellent mixing of the surrounding liquid. In this case, it is the motor (not the generator in wind or hydroelectric power plants) that is flanged to the central shaft 3a.

Claims

1. A crank driver for periodically changing an effective lever length, wherein the path of a pedal 1a is an egg-shaped circular orbit, and the crank driver comprises at least one crank 2 having an inner end 2a and an outer end 2b, and a drive gear train 4 including a first spur gear 4a having external teeth, a second spur gear 4b having external teeth, and a third spur gear 4c having external teeth, forming a gear lever; a first gear lever 7 is arranged at the inner end 2a of the crank 2, the first gear lever 7 being configured as a gear lever with a counter-rotating stage; the first gear lever 7 includes the drive gear train 4 and includes an additional first spur gear 4a' with external teeth, an additional second spur gear 4b' with external teeth, and an additional third spur gear 4c' with external teeth, and the additional third spur gear 4c' of the counter-rotation stage is non-rotatably connected to the third spur gear 4c with external teeth; 1. A crank driver, characterized in that the additional first spur gear (4a') of the counter-rotation stage is mounted on a cylindrical extension of the first externally toothed spur gear (4a) and is coupled to a chain wheel (8) so as to drive the chain wheel (8) in the same direction of rotation as the crank (2).

2. 2. The crank driver according to claim 1, wherein a second gear lever (4') is disposed on the outer end (2b) of the crank (2); either the first spur gear (4a) having teeth on the outside or the third spur gear (4c) having teeth on the outside is connected to the crank (2) by its gear shaft (4d'), and the remaining first spur gear (4a) having teeth on the outside and the third spur gear (4c) having teeth on the outside are non-rotatably connected to a frame (10) or a pedal (1a); and either the first gear lever (7) or the second gear lever (4') self-rotates in a direction opposite to the rotational direction of the crank (2).

3. 3. The crank driver according to claim 2, further comprising a drive gear train 4 having a gear ratio of 2:1:1, wherein one of the first spur gear 4a having external teeth and the third spur gear 4c having external teeth is connected to the crank 2 by its gear shaft 4d', and the other of the first spur gear 4a having external teeth and the third spur gear 4c having external teeth is non-rotatably connected to the frame 10 or the pedal 1a.

4. 4. A crank driver according to claim 1, wherein the first gear lever (7) and the second gear lever (4') each have an egg-shaped or pear-shaped housing (5) consisting of two half-shells (5a, 5b), said housing (5) being a dust-proof and watertight encapsulated unit.

5. 4. A crank driver according to claim 1, wherein the pedal position of the pedal 1a, which is non-rotatably and adjustably fixed to the first spur gear 4a or the third spur gear 4c having teeth on the outside of the second gear lever 4' and cannot rotate freely, is adjustable, thereby allowing the angular position of the second gear lever 4' relative to the crank 2 to be set.

6. 4. A crank driver according to claim 1, wherein the position of the crank (2) is adjustable by turning a ratchet mechanism or by means of a grooved shaft (4d), whereby the angular position of the first gear lever (7) or the second gear lever (4') relative to the crank (2) can be set.

7. 4. The crank driver according to claim 1, wherein at least one of the first spur gear 4a with external teeth, the second spur gear 4b with external teeth, the third spur gear 4c with external teeth, or the additional first spur gear 4a' with external teeth, the additional second spur gear 4b' with external teeth, and the additional third spur gear 4c' with external teeth has a recess extending laterally inside the gear lever 4' or 7 and reaching just below the toothed surface of the gear lever in order to fit a roller bearing 6.

8. 4. A crank driver according to claim 1, wherein the crank 2 can be extended in comparison with the standard crank length by approximately the same distance between the axes of the first externally toothed spur gear 4a, the second externally toothed spur gear 4b and the third externally toothed spur gear 4c of the first gear lever 7 or the second gear lever 4', the lever extension occurs at the 3 o'clock position of the spur gears 4a to 4c of the gear lever 4' or 7, the crank 2 has a lightning bolt-shaped portion, and the side of the outer free end 2b facing the bicycle frame 10 moves in a plane of rotation that is on the frame side relative to the inner end 2a.

9. 4. The crank driver according to claim 1, wherein the non-rotatable first spur gear (4a) having teeth on the outside of the first gear lever (7) or the second gear lever (4') is removably fixed to the bearing bracket (3).

10. 10. The crank driver according to claim 9, wherein the non-rotatable first spur gear (4a) having teeth on the outside of the first gear lever (7) is fixed to the bearing bracket (3) by a bushing (3b).

11. 4. The crank drive according to claim 1, wherein the spur gear shaft 4d' of the first gear lever 7 or the second gear lever 4' of the drive gear train 4 is arranged as a chain or belt drive 4f having a gear ratio of 2:1, and further wherein a tensioner tensions the chain or belt.

12. 4. The crank driver according to claim 1, wherein the number of teeth of the additional third spur gear 4c' having external teeth of the reverse rotation stage is the same as the number of teeth of the first spur gear 4a having external teeth and the additional first spur gear 4a' having external teeth, and the first spur gear 4a' having external teeth drives a sprocket 8 with a gear ratio of 1:1.

Images