Abstract: An apparatus including at least one drive; a first robot arm having a first upper arm, a first forearm and a first end effector. The first upper arm is connected to the at least one drive at a first axis of rotation. A second robot arm has a second upper arm, a second forearm and a second end effector. The second upper arm is connected to the at least one drive at a second axis of rotation which is spaced from the first axis of rotation. The first and second robot arms are configured to locate the end effectors in first retracted positions for stacking substrates located on the end effectors at least partially one above the another. The first and second robot arms are configured to extend the end effectors from the first retracted positions in a first direction along parallel first paths located at least partially directly one above the other.

Abstract: A substrate transport arm including a first link; a second link rotatably connected to the first link; a third link rotatably connected to the second link at a wrist joint; and a mechanical transmission having a pulley. The third link includes an end effector configured to support a substrate thereon. The mechanical transmission is connected to the third link to control rotation of the third link on the second link. The mechanical transmission is configured to control rotation of the third link as a function of an angle between the first and second links such that, as the first and second links are rotated relative to each other, the wrist joint follows a wrist path which includes a curved portion, and where a center of the substrate supported on the end effector is moved along a substantially straight substrate path as the wrist joint follows the curved portion.

Abstract: Provided is a sprocket which suppresses generation of order sounds corresponding to cycles and prevents increase in tension fluctuations, noise, and vibrations caused by resonance while alleviating the influence of the tension fluctuations corresponding to load torque fluctuations and suppressing noise and vibrations. A plurality of teeth formed to engage with a chain are arranged to form a phase fluctuation pattern of a waveform having a phase which fluctuates between positive and negative sides, and the phase fluctuation pattern is set to have parts having different wavelengths.

Abstract: An apparatus including at least one drive; a first robot arm having a first upper arm, a first forearm and a first end effector. The first upper arm is connected to the at least one drive at a first axis of rotation. A second robot arm has a second upper arm, a second forearm and a second end effector. The second upper arm is connected to the at least one drive at a second axis of rotation which is spaced from the first axis of rotation. The first and second robot arms are configured to locate the end effectors in first retracted positions for stacking substrates located on the end effectors at least partially one above the another. The first and second robot arms are configured to extend the end effectors from the first retracted positions in a first direction along parallel first paths located at least partially directly one above the other.

Abstract: A gear (10) for a bicycle transmission (20) is described, having an external contour (11) with teeth (12a, 12b) formed thereon, wherein the external contour (11) is defined by a maximum pitch diameter (Ømax) and a minimum pitch diameter (Ømin), does not have any axes of symmetry and is formed exclusively with point symmetry with respect to its centre of symmetry (M). The invention was therefore based on the problem of developing a gear (10) which improves the pedaling feel of a bicycle transmission (20). The problem is solved in that the external contour (11) exhibits a change in its curvature at every point.

Abstract: A bicycle sprocket is basically provided with a sprocket body and a plurality of chain-driving teeth. The sprocket body includes a central portion, an annular portion and an intermediate portion. The central portion has a first end surface disposed around a central opening on a side surface of the intermediate portion. The annular portion is disposed radially outward from the central portion. The intermediate portion extends between the central portion and the annular portion in a radial direction. The chain-driving teeth extend radially outward from the annular portion of the sprocket body to engage with a bicycle chain. The sprocket body includes a rib protruding from the side surface of the intermediate portion. The rib has a second end surface being axially outermost in the intermediate portion. The second end surface is farther away from the center plane than the first end surface in the axial direction.

Abstract: An apparatus including at least one drive; a first robot arm having a first upper arm, a first forearm and a first end effector. The first upper arm is connected to the at least one drive at a first axis of rotation. A second robot arm has a second upper arm, a second forearm and a second end effector. The second upper arm is connected to the at least one drive at a second axis of rotation which is spaced from the first axis of rotation. The first and second robot arms are configured to locate the end effectors in first retracted positions for stacking substrates located on the end effectors at least partially one above the another. The first and second robot arms are configured to extend the end effectors from the first retracted positions in a first direction along parallel first paths located at least partially directly one above the other.

Abstract: A bicycle crankset, which is adapted to connect to a chain, includes a chainring, a spider, and a crankarm. The chainring has teeth on an edge thereof to engage the chain and a chainring axis through a center thereof. The spider has spider arms to detachably connect to the chainring and a connecting bore. The spider has a core axis through a center of the connecting bore, and the core axis is kept a predetermined distance away from the chainring axis to form a deviation. The crankarm has an engaging member to engage the connecting bore of the spider. Tips of the teeth of the chainring move in a noncircular path when the crankarm is exerted to drive the chainring to turned, and the noncircular path is adjustable by shifting a location of the connecting bore which change the deviation.

Abstract: A transport apparatus including a drive; a first arm connected to the drive, where the first arm includes a first link, a second link and an end effector connected in series with the drive, where the first link and the second link have different effective lengths; and a system for limiting rotation of the end effector relative to the second link to provide substantially only straight movement of the end effector relative to the drive when the first arm is extended or retracted.

Abstract: Crank arm spider adjustment orientation system to provide different angular orientations in the attachment of at least an ovoid chainring, comprising an ovoid chainring (3) and a spider (1), both of them provided with multiple anchorage points (30, 10) arranged as holes distributed along the perimeter of a BCD, and mechanical anchorage means (5) engaging chainring anchorage points (30) with corresponding spider anchorage points (10); where the number of said spider anchorage points (10) is multiple of and greater than the number of said mechanical anchorage means (5), and the angular increment between consecutive chainring's (3) orientations provided by the chainring anchorage points (30) is different than the angular increment between consecutive chainring's (3) orientations provided by the spider anchorage points (10), so the combination of the spider (1) with at least one ovoid chainring (3) multiplies the possibilities for said ovoid chainring's (3) orientation reducing the angular increment between conse

Abstract: According to the present invention, an asymmetric elliptical chain gear (10) is characterized by having a shape formed by a combination of: a first ellipse (1) the major axis of which is located on the X-axis of a vertical coordinate system and the minor axis of which is located on the Y-axis of the vertical coordinate system; a first straight line (3) which is perpendicular to the minor axis, and which intersects the first ellipse (1); and a second ellipse (2) which exists on the first straight line (3) and which passes first inflection points (A, A?) that form a fixed angle (a) with respect to the minor axis in the clockwise direction, and which contacts ellipse contact points (B, B?) on the first ellipse (1) that are located at points forming a fixed angle (b) in the clockwise direction.

Abstract: A rotary component is provided, including a body that has a non-circular periphery and a plurality of teeth positioned about the periphery of the body. The non-circular periphery of the body causes variation in the tension generated in an endless drive member engaged with the rotary component during rotation of the rotary component about an axis. A valley separates each tooth from each adjacent tooth. At least one of the width of each valley and the tooth pitch is generally related to the amount of tension generated in the endless drive member during rotation of the rotary component about the axis at a time when the valley receives a belt tooth. In a preferred embodiment, both the valley width and the tooth pitch are generally related to the amount of tension generated in the endless drive member during rotation of the rotary component about the axis at a time when the valley receives a belt tooth.

Abstract: The present invention is structured by using one or both of an active wheel and a passive wheel being composed of an eccentric transmission wheel and being combined with a synchronous transmission belt for forming an eccentric wheel transmission wheel series, so that in the reciprocal treadle performed by the human's feet, when the feet input forces at different angles from the treadle shafts of the treadles to an active wheel shaft combined on the active wheel through cranks, the active wheel forms different transmission speed ratios relative to the passive wheel according to the treadle angle.

Abstract: This invention is applicable to bicycle non-circular chainrings or ovoid chainrings, attachable to a drive crank arm with a spider, forming a structure with anchorage points distributed in a star like shape; the said ovoid chainring (1) having a major diameter, whose angle with the said crank arm measured in the pedaling direction defines its orientation; whereas, said ovoid chainring has a number of anchorage points to said spider which is a multiple of the number of anchorage points of the spider, constituting multiple anchorage options to this crank arm, separated in such a distance that respective orientation values differ in 3°; and for such a small variation, the proposed constructive solution is equipping the ovoid chainring with consecutive overlapped holes and respective countersinks with different depth, forming stair steps which help supporting tangential loads to the chainring.

Abstract: According to the present invention, an asymmetric elliptical chain gear (10) is characterized by having a shape formed by a combination of: a first ellipse (1) the major axis of which is located on the X-axis of a vertical coordinate system and the minor axis of which is located on the Y-axis of the vertical coordinate system; a first straight line (3) which is perpendicular to the minor axis, and which intersects the first ellipse (1); and a second ellipse (2) which exists on the first straight line (3) and which passes first inflection points (A, A?) that form a fixed angle (a) with respect to the minor axis in the clockwise direction, and which contacts ellipse contact points (B, B?) on the first ellipse (1) that are located at points forming a fixed angle (b) in the clockwise direction.

Abstract: This invention is applicable to bicycle non-circular chainrings or ovoid chainrings, attachable to a drive crank arm with a spider, forming a structure with anchorage points distributed in a star like shape; the said ovoid chainring (1) having a major diameter, whose angle with the said crank arm measured in the pedaling direction defines its orientation; whereas, said ovoid chainring has a number of anchorage points to said spider which is a multiple of the number of anchorage points of the spider, constituting multiple anchorage options to this crank arm, separated in such a distance that respective orientation values differ in 3°; and for such a small variation, the proposed constructive solution is equipping the ovoid chainring with consecutive overlapped holes and respective countersinks with different depth, forming stair steps which help supporting tangential loads to the chainring.

Abstract: A drive transmission system for activating a cogged flexible transmission organ includes a support pulley borne idle on a drive shaft which contacts tops of the organ cogs at a calibrated circumference thereof which defines a predetermined winding radius of the flexible transmission organ. A cogged drawing pulley is mounted on the drive shaft and has cogs for enmeshing with recesses in the cogged flexible transmission organ for advancing the flexible transmission organ. The drawing pulley has cogs sized for enmeshing with the recesses of the cogged flexible transmission organ, such that tops of the drawing pulley cogs are displaced from bottoms of the drawing pulley recesses. The drawing pulley therefore cannot drag on the flexible transmission organ when the support pulley is not subject to drive torque.

Abstract: A synchronous drive apparatus that includes a continuous loop elongate drive structure and first and second driven rotors that are configured to cooperate with the continuous loop elongate drive structure to generate first and second opposing fluctuating corrective torques, respectively, that are configured to at least partly counteract first and second periodic fluctuating load torques, respectively.

Abstract: A synchronous drive apparatus includes first and a second rotors. The rotors have multiple teeth for engaging engaging sections of an elongate drive structure. A rotary load assembly couples to the second rotor. The elongate drive structure engages about the rotors. The first rotor drives and the second rotor is driven by the elongate drive structure. One of the rotors has a non-circular profile having at least two protruding portions alternating with receding portions. The rotary load assembly presents a periodic fluctuating load torque when driven in rotation. The angular positions of the protruding and receding portions of the non-circular profile relative to the angular position of the second rotor, and the magnitude of the eccentricity of the non-circular profile, are such that the non-circular profile applies to the second rotor an opposing fluctuating corrective torque which reduces or cancels the fluctuating load torque of the rotary load assembly.

Abstract: A drive transmission system for activating a cogged flexible transmission organ includes a support pulley borne idle on a drive shaft which contacts tops of the organ cogs at a calibrated circumference thereof which defines a predetermined winding radius of the flexible transmission organ. A cogged drawing pulley is mounted on the drive shaft and has cogs for enmeshing with recesses in the cogged flexible transmission organ for advancing the flexible transmission organ. The drawing pulley has cogs sized for enmeshing with the recesses of the cogged flexible transmission organ, such that tops of the drawing pulley cogs are displaced from bottoms of the flexible transmission organ recesses and tops of the flexible transmission organ cogs are displaced from bottoms of the drawing pulley recesses. The drawing pulley therefore cannot drag on the flexible transmission organ when the support pulley is not subject to drive torque.

Abstract: In a timing chain driving system in which the speed of a driving sprocket fluctuates cyclically, the tooth pitch of a driven sprocket from which a tension span of the chain travels toward the driving sprocket varies cyclically around the circumference of the driven sprocket so that the tooth pitch at the point at which the timing chain disengages from the driven sprocket is at a minimum when the rotational speed of the driving sprocket is maximum, moderating fluctuations in chain tension. A similar effect can be achieved in the case of a driving sprocket having a cyclically varying tooth pitch by arranging the driving sprocket so that its tooth pitch is maximum at the point at which it is engaged by the chain when its rotational speed is maximum.

Abstract: In a timing chain drive unit the tooth pitch of a driven sprocket from which a tension span of the chain travels toward a driving sprocket varies cyclically around the circumference of the driven sprocket and cyclically increases and decreases the length of the tension span in synchronism with load variations imparted to the driven sprocket by a valve-operating camshaft.

Abstract: A sprocket for transferring a force between a chain and a drive element that includes a plurality of teeth and a plurality of openings proximate the teeth. Each tooth has a load-bearing flank and a non-load-bearing flank. One of the plurality of openings are arranged relative to one of the plurality of teeth, in one-to-one correspondence therebetween, such that the opening is asymmetrically divided by a radial centerline of the tooth, a first load strip is formed between the opening and the load-bearing flank of the tooth, and a second load strip is formed between the opening and the non-load-bearing flank of the tooth.

Abstract: A belt drive is provided, especially a timing-belt drive for an internal-combustion engine, with a driving gear of a driveshaft, at least one driven gear of a driven shaft, and a belt means, wherein the driving or the driven gear imparts additional irregularity to the belt drive due to its noncircular shape and its phase position, which leads to stable running of the belt means. A noncircular gear that can be mounted easily and in phase, as well as with a fixed position, is realized in that the driving or driven noncircular gear has in its in-phase rotational position a rotationally fixed connection to its driving or driven shaft.

Abstract: A synchronous belt drive system comprising an obround sprocket (10) having a toothed surface and at least one linear portion (16) disposed between two arcuate portions (14,15), the arcuate portions having a constant radius (R1, R2), the linear portion having a predetermined length, a second sprocket (300) having a toothed surface, the second sprocket engaged to the obround sprocket by an endless toothed member (200), the second sprocket connected to a rotary load, the rotary load having cyclic torque fluctuations, and a radius (R1) of the obround sprocket (10) oriented at a belt entry point (201) which coincides with a maximum amplitude of a cyclic torque fluctuation such that a span length (SL) of the endless toothed member is made to vary in a manner that substantially cancels the cyclic torque fluctuations.

Abstract: A chain guide mount is adapted to be attached on a bicycle having a frame including a bottom bracket shell. A bottom bracket sleeve is position in the shell, and the sleeve includes a first anti-rotation feature. The chain guide mount has mounting locations for attachment of a chain guide, and further has a second anti-rotation feature engaging the first anti-rotation feature to thereby inhibit rotation of the chain guide mount relative to the sleeve. In one embodiment, the sleeve includes a cylindrical part position in the shell and a flange positioned outside the shell. In order to insure proper rotational orientation of the chain guide mount, the first and second anti-rotation features are preferably asymmetrically positioned around a bottom bracket axis defined by the bearing. In addition, a first alignment feature is provided on the frame, and the sleeve includes a second alignment feature engaging the first alignment feature.

Abstract: A synchronous drive apparatus includes first and a second rotors. The rotors have multiple teeth for engaging engaging sections of an elongate drive structure. A rotary load assembly couples to the second rotor. The elongate drive structure engages about the rotors. The first rotor drives and the second rotor is driven by the elongate drive structure. One of the rotors has a non-circular profile having at least two protruding portions alternating with receding portions. The rotary load assembly presents a periodic fluctuating load torque when driven in rotation. The angular positions of the protruding and receding portions of the non-circular profile relative to the angular position of the second rotor, and the magnitude of the eccentricity of the non-circular profile, are such that the non-circular profile applies to the second rotor an opposing fluctuating corrective torque which reduces or cancels the fluctuating load torque of the rotary load assembly.

Abstract: Improvement in the design of variable original radius chainrings for coupling to conventional bicycle cranks in order to apply traction, which primarily consists of its being provided with a plurality of possible anchorages to the crank, so that the user may adjust the relative position between the crank and the major radius of the chainring, and thus optimize the biomechanics of his own pedalling; furthermore, other design parameters are offered to endow this non-circular pedalling with leg speeds optimized within the limitation of pedalling with cranks at 180 degrees and therefore with a dead spot.

Abstract: A synchronous drive apparatus that includes a continuous loop elongate drive structure and first and second driven rotors that are configured to cooperate with the continuous loop elongate drive structure to generate first and second opposing fluctuating corrective torques, respectively, that are configured to at least partly counteract first and second periodic fluctuating load torques, respectively.

Abstract: A continuously variable transmission for transmitting torque with at least one input shaft introducing torque into the continuously variable transmission, with at least one further shaft, to which the torque is to be transmitted, and a force-transmitting endless element, which has a non-positive connection to the at least one input shaft and the at least one further shaft. A connection between either the at least one input shaft or the at least one further shaft and the force-transmitting endless element is provided by a rotary disk (10) around which the force-transmitting endless element is wrapped. The continuously variable transmission is characterized in that the rotary disk (10) has a radius (20), which is dependent functionally on a rotational angle and a certain mean radius. The invention further relates to an out-of-round rotary disk (10) for providing a non-positive connection.

Abstract: The configuration of teeth (20) and spacewidths (22) of a rotary disc (10) which is rotatable about a rotational axis (12) are provided. Here, the spacewidths (22) are in each case arranged symmetrically with respect to a spacewidth axis of symmetry (30), with a rotary disc radius being dependent on a rotational angle and a certain mean radius. The spacewidth axes of symmetry (30) of the rotary disc (10) are aligned towards the local centers of curvature, that is to say towards the center of curvature of the curve at the point at which the spacewidth axis of symmetry (30) intersects the peripheral line of the rotary disc (10). Formed around the rotational axis (12) is a circle axis (14) which is not intersected by any of the spacewidth axes of symmetry (30).

Abstract: In a timing chain drive unit the tooth pitch of a driven sprocket from which a tension span of the chain travels toward a driving sprocket varies cyclically around the circumference of the driven sprocket and cyclically increases and decreases the length of the tension span in synchronism with load variations imparted to the driven sprocket by a valve-operating camshaft.

Abstract: A rotary component with a rotor having a plurality of teeth arranged around the perimeter of the rotor. Each tooth has a crown and each pair of adjacent teeth has a valley therebetween. The crowns of the teeth lie on a curved envelope forming the perimeter of the rotor. The perimeter of the rotor has a non-circular profile with at least two protruding portions alternating with receding portions, in which the distance between the midpoints of the crowns of each pair of adjacent teeth is substantially the same, the profile of the valley between each pair of adjacent teeth is substantially the same, and the distance between the midpoint of each crown and the axis of the rotor varies around the perimeter to produce the said non-circular profile.

Abstract: A chain drive is provided including a plurality of shafts (2, 4, 5), which are connected to the drive, each having one sprocket (3, 6, 7), and a chain (8) which is guided over the sprockets (3, 6, 7). At least one sprocket (3) is non-circular in order to reduce the chain forces which result from the disturbance vibrations introduced into the drive (1). The chain (8) is formed of links (9, 10, 11) which are connected to one another by pin-like connecting elements (15) and which have connection apertures (12, 13, 14), and the connection apertures (12, 13, 14) of all the links (9, 10, 11) are normally punched.

Abstract: A vibration canceling rotor and a synchronous drive employing such rotors is provided wherein 1.5 order vibrations in the synchronous drive can be reduced by employing the vibration canceling rotor on a rotating member of the synchronous drive that rotates at one half the speed of another rotating member of the drive. To cancel 1.5 order vibrations, the rotor has a three-lobed non-circular radial profile to engage the continuous-loop elongate drive structure of the synchronous drive. To cancel 1.5 order and 3rd order vibrations, the rotor has a six lobed non-circular radial profile overlaid on the three lobed profile to create a non-circular composite profile to engage the continuous-loop elongate drive structure. The continuous-loop elongate drive structure can be a chain or a toothed belt.

Abstract: A rotating disk is provided, which can rotate by a rotational angle about a rotational axis (12) and has a number of teeth (20) arranged on a periphery of the rotating disk (10) and tooth spaces (22) located between the teeth, through whose middle runs a tooth-space middle line (30), and the rotating disk (10) has a periodically changing tooth-space geometry. The rotating disk (10) has a tip circle radius (24) that is constant. In addition, a drive device and a belt drive with a rotating disk (10) are provided.

Abstract: In a chain transmission, a sprocket having an elastic ring sandwiched between a central hub and an annular toothed outer member, the tooth form is such that the root diameter, that is, the diameter of the tooth gap bottom circle, is greater than the root diameter in a sprocket having a standard ISO tooth form.

Abstract: In a chain transmission a standard ISO roller chain meshes with a modified sprocket having a root diameter larger than the root diameter of a standard sprocket designed for use with the standard chain. The angular tooth pitches can be either of two kinds. In a first version, the sprocket has two irregularly distributed tooth pitches, ???? and ?+2??, there being two tooth pitches ???? for each tooth pitch ?+2??. In a second version, the sprocket has three angular tooth pitches, ????, ?, and ?+??, in equal numbers, also distributed irregularly.

Abstract: A synchronous belt drive system comprising an obround sprocket (10) having a toothed surface and at least one linear portion (16) disposed between two arcuate portions (14,15), the arcuate portions having a constant radius (R1, R2), the linear portion having a predetermined length, a second sprocket (300) having a toothed surface, the second sprocket engaged to the obround sprocket by an endless toothed member (200), the second sprocket connected to a rotary load, the rotary load having cyclic torque fluctuations, and a radius (R1) of the obround sprocket (10) oriented at a belt entry point (201) which coincides with a maximum amplitude of a cyclic torque fluctuation such that a span length (SL) of the endless toothed member is made to vary in a manner that substantially cancels the cyclic torque fluctuations.

Abstract: In a roller or bushing chain transmission a standard roller or bushing chain having a uniform chain pitch meshes with a sprocket having at least two different tooth form pitches.

Abstract: A synchronous drive apparatus and method, wherein the apparatus comprises a plurality of rotors comprising at least a first and a second rotor. The first rotor has a plurality of teeth for engaging the engaging sections of an elongate drive structure, and the second rotor has a plurality of teeth for engaging the engaging section of the elongate drive structure. A rotary load assembly is coupled to the second rotor. The elongate drive structure engages about the first and second rotors. The first rotor is arranged to drive the elongate drive structure and the second rotor is arranged to be driven by the elongate drive structure. One of the rotors has a non-circular profile having at least two protruding portions alternating with receding portions.

Abstract: This invention concerns a sprocket gear for facilitating the derailing of the chain of a bicycle transmission and other prime movers. The sprocket gear includes at least two sprockets axially and concentrically positioned relative to one another. Each sprocket includes a perimeter, a front face, and a back face. Gear teeth project axially from at least a first perimeter segment of the front face and at least a second perimeter segment of the front face is free of gear teeth. Gear teeth project axially from the back face perimeter at the at least second segment of the front face. No gear teeth project from the back face perimeter at the at least first perimeter segment of the front face.

Abstract: A chain drive for pivot chains (7) or round link chains (8) having spur gears (2) and a polygonal chain wheel (10) reduces variations in velocity and acceleration transferred to the chains (7), (8). The driven gear wheel (3a) and the driving gear wheel (4a) consist of noncircular gear wheels having a set gear ratio adjustment so that the driving gear wheel (4a) is put in such a position to the driven gear wheel (3a) so that the slowest angular velocity coincides with the corners (29a) of the polygon of the chain wheel (10) and the fastest angular velocity occurs at the middle of the polygon straight lines (29b) of the chain wheel.

Abstract: This invention includes a sprocket assembly for facilitating the derailing of the chain of a bicycle transmission and other prime movers. The first embodiment of the invention relates to a sprocket gear having at least two sprockets axially and concentrically positioned relative to one another. Each sprocket includes a non-circular configuration having at least one long radius and at least one short radius. The sprockets being axially aligned adjacent to one another such that the short radius of one sprocket is axially substantially aligned with and substantially equal in length with said long radius of an adjacent sprocket. The second embodiment of the present invention provides a sprocket assembly having two sprockets with the tooth being displaced by less than one tooth relative to each other. Thus, it is possible to vary the relationship between the teeth of the small sprocket and the chain to engage these teeth without having to vary the phase relationship between the larger and smaller sprockets.

Abstract: A synchronous drive apparatus and method, wherein the apparatus comprises a plurality of rotors comprising at least a first and a second rotor. The first rotor has a plurality of teeth for engaging the engaging sections of an elongate drive structure, and the second rotor has a plurality of teeth for engaging the engaging section of the elongate drive structure. A rotary load assembly is coupled to the second rotor. The elongate drive structure engages about the first and second rotors. The first rotor is arranged to drive the elongate drive structure and the second rotor is arranged to be driven by the elongate drive structure. One of the rotors has a non-circular profile having at least two protruding portions alternating with receding portions.

Abstract: In order to provide an operationally reliable compensation in particular for polygon effects, using simple means, the invention proposes a drive to be used for a chain comprising periodically arranged chain links, the drive train of which is driven by a driving motor and has at least one non-circular wheel located on the input side.

Abstract: A bicycle chain guide device includes a plate mounted to the crank axle has two protrusions and each of the protrusions has a first roller and a second roller connected thereto. The chain engaged with a chainwhell passes between the first roller and the second roller on each of the two protrusions.

Abstract: An adjustable bicycle chain guide device includes a plate mounted to a crank axle and the plate has two protrusions. Two rollers each have an extension and the two extensions are respectively connected to the two protrusions. Each of the extensions has two holes defined therethrough and each of the protrusions has two rows of positioning holes so that the positions of the rollers are adjusted on the protrusions by engaging bolts with different positioning holes.

Abstract: An elliptic gearing for a bicycle has an elliptic driving gear rotatably mounted at a bottom-front end of a frame of the bicycle by a crank axle extending through the frame. A driven gear is rotatably mounted at a bottom-rear end of the frame. A chain connects the elliptic driving gear and the driven gear. Two cranks extend oppositely and are respectively mounted at two ends of the crank axle. The cranks are parallel to the maximum diameter of and perpendicular to the minimum diameter of the elliptic driving gear. Two pedals are pivotally mounted on distal ends of the cranks respectively. An adjusting device is mounted beneath the driven gear and connected to the driving and the driven gear by the chain.

Abstract: A chain drive for pivot chains (7) or round link chains (8) having spur gears (2) and a polygonal chain wheel (10) reduces variations in velocity and acceleration transferred to the chains (7), (8). The driven gear wheel (3a) and the driving gear wheel (4a) consist of noncircular gear wheels having a set gear ratio adjustment so that the driving gear wheel (4a) is put in such a position to the driven gear wheel (3a) so that the slowest angular velocity coincides with the corners (29a) of the polygon of the chain wheel (10) and the fastest angular velocity occurs at the middle of the polygon straight lines (29b) of the chain wheel.