Pedal-shift type crank rotation drive mechanism

Abstract

(Technical field to which the invention belongs) This invention relates to a crank rotation drive mechanism that includes left and right pedals that alternately apply external forces to a pair of left and right crank arms attached to a crankshaft, and an output part that rotates integrally with the crankshaft. (Technical problem to be solved) To provide a crank rotation drive mechanism that does not require a large amount of leg strength and can be used for a long period of time. (Key points of the solution) A pedal-shift type crank rotation drive mechanism Z is provided which includes a pair of left and right crank arms CA and a crank rotation shaft CX2 fixed to a crankshaft CX1 pivotally supported on a frame F or the like, a pair of left and right swing arms A pivotally supported on a fixed swing fulcrum axis A4 located away from the crankshaft CX1, a first slider S1 that is pivotally supported on the crank rotation shaft CX2 and that moves back and forth along the longitudinal direction of the swing arm A, a second slider S2 that abuts or does not abut on the first slider S1 and intermittently moves back and forth, and a pedal P that is attached to a block S21 in front of the second slider and that swings the swing arm A to rotate the crankshaft CX1 while tracing a substantially oval trajectory, rotation output being applied to the output part 5. (Main use of the invention) In addition to general bicycles, tricycles for physically disabled people or for business use, fitness equipment, or labor-saving devices and equipment, etc.

Description

Pedal shift type crank rotation drive mechanism

[0001] The present invention relates to a pedal-shift crank rotation drive mechanism that includes left and right pedals that alternately apply external forces to a pair of left and right crank arms attached to a crankshaft, and an output section that rotates integrally with the crankshaft.

[0002] A conventional crank rotation drive system of this type is disclosed in, for example, Patent Document 1 (see

[0011] to

[0021] , FIGS. 1 and 2).

[0003] This system comprises a pedal shaft 10 that is fixed to the frame 3 and does not rotate itself, guide members 11a, 11b that rotate within a certain angle around the pedal shaft, and rotatable pedals 12a, 12b that are attached to the guide members 11a, 11b and move up and down reciprocally.

[0004] Guide grooves 13a and 13b are formed on the insides of the guide members 11a and 11b, respectively, and protruding members 26a and 26b formed integrally with the crank cams 22a and 22b are received in the guide grooves. The crank cams 22a and 22b are integrally assembled to a crankshaft 20, and a gear 21 is also integrally assembled to the crankshaft.

[0005] When the pedals 12a, 12b move up and down, the protruding members 26a, 26b rotate along the guide grooves 13a, 13b, and at the same time, the crank cams 22a, 22b, the crank shaft 20, and the gear 21 rotate. When the gear 21 rotates, the gear 31 meshed therewith rotates in the opposite direction, and the chain gear 32 formed integrally with the gear 31 also rotates together.

[0006] The fixed shaft 30 is assembled and fixed to the frame 3 and does not rotate, and only the gear 31 and the chain gear 32 rotate. Therefore, the gear 31 and the chain gear 32 are assembled to the fixed shaft 30 via bearings.

[0007] This device operates smoothly when, when one pedal 12a is at the top dead center and the other pedal 12b is at the bottom dead center, the protruding members 26a, 26b of the crank cams 22a, 22b are inclined at a certain angle θ3 in the direction of rotation past the vertical center line of the crankshaft 20.

[0008] This configuration can be applied to saddleless bicycles that move forward by pedaling up and down. The pedals operate smoothly, and the up and down movement of the pedals is easily converted into rotational movement. Furthermore, by riding while standing, the user can get a full-body workout compared to riding a bicycle while sitting.

[0009] Special Publication No. 2010-508191

[0010] However, in the conventional crank rotation drive system described above, when the pedals are raised and lowered, the movement locus is a circular arc shape that repeatedly moves up and down, with the same locus centered on the pedal shaft 10. This results in unnatural leg movements of the user that differ from the bending and stretching of the legs when a person walks, making it difficult to fully exert leg strength and making the legs prone to fatigue, making it difficult to use for long periods of time.

[0011] As described above, although the conventional crank rotation drive system has a simple overall structure, such as a fixed pedal shaft 10, there are still issues to be resolved regarding the convenience of the device, etc. Therefore, there has been a demand in this technical field for a crank rotation drive system or mechanism that does not require a great deal of leg strength and can be used for long periods of time.

[0012] (Characteristic Configuration) The pedal shift type crank rotation drive mechanism according to the present invention is characterized by the following: a pair of left and right crank arms fixed to both ends of a crank shaft rotatably attached to a frame or the like, and operating with an operating phase angle difference of 180 degrees; a crank rotating shaft provided at the tip of each of the pair of left and right crank arms; a pair of left and right swing arms journaled on a fixed swing fulcrum shaft that is fixedly disposed on the frame or the like at a position away from the crank shaft by more than the length of the crank arms; a pair of left and right first sliders journaled rotatably on the crank rotating shafts and held by the swing arms, capable of reciprocating along the longitudinal direction of the swing arms, with the first slider tip-side abutment portion and the first slider rear-side abutment portion held in opposite directions, and moving integrally in the longitudinal direction when the direction of the fixed swing fulcrum shaft in the longitudinal direction is the rear end side and the opposite direction is the tip side; a pair of left and right second sliders that are held by the swing arm and are reciprocatable along the longitudinal direction of the swing arm, wherein a second slider front end abutment portion and a second slider rear end abutment portion that move integrally in the longitudinal direction are held facing each other with a predetermined interval between them, and the second sliders intermittently reciprocate within a movable range in the same direction as the reciprocating movement of the first slider due to abutment or non-abutment between the opposing first slider front end abutment portion and the second slider front end abutment portion, or abutment or non-abutment between the opposing first slider rear end abutment portion and the second slider rear end abutment portion; a pair of left and right pedals attached to a second slider front block configured to be positioned further towards the tip side than the first slider of the oscillating arm during the reciprocating movement of the first slider, which alternately oscillates the left and right oscillating arms by its alternating operation, and which, in conjunction with the oscillation, applies a rotational force to the crank arm via the first slider while tracing a deformed elliptical trajectory, and at the same time applies a rotational force to the crankshaft, and a rotational output is applied to an output section which rotates integrally with the crankshaft.

[0013] The pedal-shift crank rotation drive mechanism of this configuration has a first slider rotatably supported on a crank rotation shaft provided at the tip of a pair of left and right crank arms, and a swing arm that swings back and forth holds the first slider so that it can move longitudinally. The first slider has a first slider front-end abutment portion and a first slider rear-end abutment portion that move integrally with the first slider and face in opposite directions.

[0014] A pair of left and right swing arms are each provided with a second slider. The second slider has a second slider front-end abutment portion and a second slider rear-end abutment portion that move integrally and are oriented facing each other with a predetermined gap between them. As the first slider reciprocates, the second slider intermittently reciprocates within its movable range in the same direction as the first slider reciprocates, due to contact or non-contact between the first slider front-end abutment portion and the second slider rear-end abutment portion, which are provided in a facing state. The range of this movement is smaller than the range of movement of the first slider by the amount of the movement interruption.

[0015] The pair of left and right second sliders have a second slider front block located further towards the tip of the first slider on the oscillating arm during the reciprocating movement of the first slider, and the alternating operation of the pair of left and right pedals attached to this second slider front block causes the left and right oscillating arms to oscillate alternately, applying a rotational force to the crankshaft, and the trajectory of the pedal axis, combined with the oscillation of the oscillating arms, describes a circular trajectory that is a deformed ellipse with a top-to-bottom major axis that bulges out on the front-to-back minor axis sides more than the length of the crank arm as a whole.

[0016] In this case, the front end face of the first slider may be the first slider front-end contact portion in the longitudinal direction of the swing arm, and the rear end face may be the first slider rear-end contact portion.Also, the rear end face of the second slider front block may be the second slider front-end contact portion.

[0017] The reciprocating distance of the first slider is the crank circle diameter traced by the rotational path of the crank pivot axis. In this proposal, a crank having a pair of crank arms and a crank pivot axis of a predetermined length is practically adopted. Here, this is referred to as the practical crank, and the rotational path of the crank pivot axis is referred to as the practical crank circle. The second slider front block to which the pedal is attached is located closer to the tip of the swing arm than the first slider. For example, while the first slider moves back and forth on the swing arm in response to the operation from the start to the end of the pedal operation, the second slider front block approaches the tip block of the swing arm until they come into contact due to the direction of the operating force.

[0018] When the swing arm swings, only when the first slider front-end abutment portion or the first slider rear-end abutment portion of the first slider abuts against the second slider front-end abutment portion or the second slider rear-end abutment portion, the second slider moves in the same longitudinal direction in conjunction with the first slider due to this abutment. A pedal is provided on the second slider front block, which is located closer to the swing arm front end than the first slider, and input is transmitted via the pedal to the swing arm, first slider, crank pivot shaft, and crank arm.

[0019] With this configuration, the left and right swing arms continuously swing back and forth through a predetermined angle in response to the alternating operation of the pair of left and right pedals, and the operating force of this swing arms causes the first slider to move back and forth in conjunction with the first slider, and the crank arm and crank rotating shaft continuously rotate in a predetermined direction, causing the crank shaft to continuously rotate in the same direction, thereby generating rotational output.At this time, the second slider intermittently moves back and forth in the same direction as the movement of the first slider in the longitudinal direction of the swing arm due to the abutment and non-abutment between its two abutment portions and the abutment portions of the first slider.

[0020] While the pair of left and right oscillating arms are swinging back and forth, the pair of left and right pedals attached to the second slider front block can also move back and forth along the longitudinal direction of the oscillating arms, making it possible to change the distance from the fixed oscillating fulcrum axis, which is the oscillating fulcrum of the oscillating arms, to the pedals.

[0021] Furthermore, the pedal shift type crank rotation drive mechanism of this configuration is basically configured with the basic line connecting the fixed oscillating fulcrum axis and the crank axis center horizontal, and will be mainly described in this form hereinafter; however, depending on the embodiment and usage situation to be used, the basic line can be tilted along with the entire mechanism by an appropriate predetermined angle above or below horizontal, including horizontal, around the crank axis center or the fixed oscillating fulcrum axis, without changing the correlation of the entire configuration; in other words, it can be mounted and used with the angle tilted as viewed in the crank axis direction, making it suitable for a wider range of uses.

[0022] Now, assuming that the direction of the base line connecting the fixed pivot axis and the crank axis is horizontal, the top and bottom dead centers of the crank pivot shaft in this configuration are the points of contact with the actual crank circle on the upper and lower tangent lines drawn from the fixed pivot axis to the actual crank circle. In contrast, the highest point on the actual crank circle is the topmost point, and the lowest point is the bottommost point. If the rotation direction of the crank pivot shaft is from top dead center to bottom dead center via the bottommost point, the topmost point is a position that has definitely passed top dead center, and the bottommost point is a position that has not yet reached bottom dead center. Therefore, the range in which the swing arm can be swung and the crank arm rotated by actuating one pedal is basically from the point where the crank pivot shaft passes top dead center on the actual crank circle, where no pedal force is generated, to bottom dead center, where no pedal force is generated.

[0023] However, in this configuration, which has a pair of crank arms with a phase angle difference of 180 degrees, the practical range is the point of symmetry of the phase angle position 180 degrees back from bottom dead center on the crank circle used in the practical application, centered on the crank axis, that is, from the point of line symmetry of top dead center across the reference line when the line connecting the highest point and lowest point is taken as the reference line of the practical application crank circle, to bottom dead center, and in this case, the pedal actuation position corresponding to that point becomes the pedal actuation start point.

[0024] However, in this configuration, the rotation range of the crank rotation axis when each pedal is operated is determined by appropriately setting a predetermined distance between the abutment portions on the leading and rear ends of the second sliders, which are held in the directions facing each other on the second sliders. In other words, the rotation range of the crank rotation axis when the pedal is operated can be from the line symmetrical point of the top dead center to the bottom dead center, or from the highest point (or its vicinity) to the lowest point (or its vicinity), although both are possible, and are set as design specifications.

[0025] If we now consider the rotational range of the crank pivot axis when the pedals are operated to be from the highest point to the lowest point (hereinafter referred to as "this case"), when one pedal is operated, the opposing crank pivot axis is at the rotation start point, and when the other pedal is next operated (this will be called the operating stroke), the crank pivot axis of that pedal will passively rotate from the lowest point in the crank circle to the rotation start point, i.e., the highest point (this will be called the return stroke). One cycle of the crank pivot axis locus, combining the operating stroke and return stroke of each pedal, is from the highest point to the highest point, or from the lowest point to the lowest point when taken from the start of the return stroke.

[0026] In this case, during the operating stroke of one pedal, the crank pivot axis rotates in the direction of the base line toward the lowest point via the midpoint of the operating stroke that is farthest from the fixed swing fulcrum axis on the crank circle in the working stroke. Furthermore, if the first slider side end face of the second slider front block is the second slider tip-side abutment part, during the initial rotation from the operating start point to the midpoint on the crank circle in the working stroke, the pedal is attached to the second slider front block whose second slider tip-side abutment part is already in a state of abutting against the first slider tip-side abutment part at the operating start point, and is maintained in a state on the tip side of the swing arm.

[0027] Then, in this state, the pedal is operated to rotate the swing arm, and the operating force moves the first slider via the crank pivot shaft, bringing the entire second slider closest to the swing arm's tip block, which is the end of the swing arm's range of movement.

[0028] When the pedal is actuated in this way in the first stage of rotation of the operating stroke, the pedal shaft, in conjunction with the swing of the swing arm, traces a curved locus that bulges downward toward the tip.

[0029] During the remaining second stage of the crank arm's rotation, which is the first half of its rotation, only the first slider moves toward the fixed pivot axis according to the crank circle locus until the crank pivot axis reaches its lowest point. However, the pedal attached to the front block of the second slider reaches abutment against the pivot block due to the opposing directions of the actuating forces, thereby completing its operation. As a result, the pedal axis, in conjunction with the swing of the swing arm, traces a partial arc locus with the fixed pivot axis as its center and the distance to the pedal axis as its radius. At this time, the rear end abutment portion of the first slider, i.e., the rear end face, approaches the rear end abutment portion of the second slider closest to the rear end abutment portion of the second slider without coming into contact with it until the axis of the crank pivot shaft supporting the first slider reaches its lowest point. This is the first prerequisite, which is an important requirement in this case, that the rear end contact portion of the first slider does not contact the rear end contact portion of the second slider until the rotation axis of one of the cranks reaches its lowest point.

[0030] However, in this case, even if one of the pedals is further operated, the rear end abutment portion of the first slider on that side will soon abut against the rear end abutment portion of the second slider, and the rearward force due to the crank rotating force acting on the first slider and the forward operating force acting on the second slider will oppose each other, preventing operation, and the distance between the forward end abutment portion of the second slider and the rear end abutment portion of the second slider is set so that the axis of the crank rotating shaft that pivotally supports the first slider will end its operating stroke without moving significantly beyond its lowest point.Then, when the other pedal is subsequently operated, the return stroke of one of the crank rotating shafts will begin, and with the rear end abutment portion of the first slider on that side coming into contact with the rear end abutment portion of the second slider, both will begin moving toward the rear end of the swing arm.

[0031] These structural requirements, the longitudinal travel of the first slider, which is appropriately set depending on the user and the conditions of use (as described below), the lengths of the first and second sliders, the required lengths of other components, and the appropriate and necessary clearances are all considered in the design specifications. To achieve compactness, the swing arm is also set to the minimum necessary length possible without unnecessary extension. For example, compared to conventional crank rotation drive mechanisms used in bicycles, swing arm pedal shift crank rotation drive mechanisms like the one described here tend to be longer in the longitudinal direction, which can lead to fundamental problems such as interference between the operating leg and the front wheel of the bicycle. To prevent this, the second prerequisite of this important requirement is to keep the swing arm to the minimum necessary length possible.

[0032] Therefore, taking everything into consideration, the basic idea of ​​this configuration is to satisfy the design specifications of the first and second prerequisites.

[0033] Here again, when pedaling with the legs as in a bicycle, for example, the depression stroke is the travel from the pedal depression start point, which corresponds to the highest point on the crank circle where a pair of left and right crank arms and crank pivot shafts are actually used, to the pedal depression end point, which corresponds to the lowest point, and the return stroke before the depression stroke is the travel from the depression end point to the start point. The return stroke is performed by the depression strokes on the opposing sides.

[0034] During the return stroke, when one pedal rotates the crank arm upward from its lowest point on the crank circle (the end point of the pedal stroke in the practical application) to a line passing through the fixed swing fulcrum axis and the crank axis, the rear end of the first slider on the swing arm abuts against the rear end of the second slider, and the entire second slider moves toward the fixed swing fulcrum axis to its closest position without abutting against the rear block on the fixed swing fulcrum axis side of the swing arm. Accordingly, the pedal attached to the front block of the second slider also moves closest to the fixed swing fulcrum axis by the same distance. As a result, the pedal axis, coupled with the swing of the swing arm, describes an arc of approximately a quarter ellipse, bulging outward by approximately the radius of the practical crank circle toward the rear end of the base line. In this case, the longitudinal direction of the crank arm and the swing arm also coincides with the direction of a line passing through the axis of the swing arm fixed swing fulcrum and the axis of the crank.

[0035] The desirable operation in the latter stage of the return stroke, in which the crank arm continues to rotate to the highest point, is for the first slider to move toward the tip of the swing arm A based on the trajectory of the crank circle performed only by the first slider, so that the tip abutment portion of the first slider, i.e., the tip end face, comes closest to the tip abutment portion of the second slider front block, i.e., the rear end face, without coming into contact with it, and ends the return stroke.

[0036] However, during that time, i.e., in the latter part of the return stroke, the second slider remains stopped in the longitudinal direction of the swing arm, and therefore, in conjunction with the swing of the swing arm, the pedal axis of the pedal attached to the front block of the second slider traces a partial arc curved trajectory upward toward the rear end, with the radius being the distance to the pedal axis from the fixed swing fulcrum axis.

[0037] In this case, by setting the length of the swing arm, which is the second prerequisite, to the minimum possible length, the leading end face of the first slider and the rear end face of the second slider front block, to which the pedal is attached, which has been swinging in an upward, partially arcuate trajectory, will come into contact not at the transition between strokes but near the top dead center, just before the crank pivot axis reaches its uppermost point, in the latter part of the return stroke, causing a sudden change in direction and creating an uneven spot in the pedal axis trajectory. While this is not desirable for pedal movement, it provides a good opportunity to time the subsequent pedal depression during use.

[0038] From the results so far, if the rotation range of the crank pivot axis when operating the pedal is from the highest point to the lowest point, the operating trajectory of the pedal axis after one cycle has a point where the direction changes suddenly, but in combination with the swing of the swing arm, it bulges downward and forward of the swing arm, and after the lowest point of the return stroke of the axis of the crank pivot shaft, it bulges by an amount of displacement in the base line direction corresponding to the amount of movement towards the rear end, that is, by approximately the radius of the crank circle used in the embodiment, and as a whole it describes a deformed oval circle with a large front-to-back width on the short axis side that is more accommodating to the folding and pushing movements of a person's legs, and a shape that is not found in conventional fixed fulcrum swing arm crank rotation drive systems such as those shown in Patent Document 1.

[0039] To minimize the required length of the swing arm, first, the narrow angle (called the basic narrow angle) formed by the basic line passing through the fixed swing fulcrum axis and the crank axis and the line passing through the fixed swing fulcrum axis and the highest point on the practically used crank circle is set, and the practically used crank circle diameter is set. This uniquely determines the distance from the fixed swing fulcrum axis to the crank axis. When the crank rotation axis is at the farthest position on the practically used crank circle from the fixed swing fulcrum axis, that is, the intersection of the practically used crank circle and the extension line connecting the fixed swing fulcrum axis and the crank axis, the length of the swing arm is set to the minimum required length when the second slider front block is located at the tip of the first slider at a position calculated by adding the radius of the practically used crank circle to the distance from the fixed swing fulcrum axis to the crank axis, and the swing arm tip block is located at the tip of that, with an appropriate gap between them.

[0040] The basic narrow angle is the same narrow angle formed by the line connecting the highest point and the lowest point with the fixed swing fulcrum axis and the basic line, and the range from 20 degrees to 35 degrees is desirable overall. As will be described later, the basic narrow angle is set with a certain degree of flexibility, while the crank circle diameter used in the actual operation is set based on the length of each crank arm, which is appropriately set depending on the user and the conditions of use when pedaling a general normal crank.

[0041] Next, for example, with regard to the distance between the contact portion on the tip side of the second slider and the contact portion on the rear side of the second slider when the rotation range of the crank rotation axis when the pedal is depressed (activated) is from the highest point to the lowest point, if the swing arm is to be made the minimum necessary length in light of the second condition, in addition to the first prerequisite that when one crank rotation axis reaches the lowest point at the end of the depression stroke in the crank circle used in the embodiment, the rear end face which is the contact portion on the rear side of the first slider will not contact the contact portion on the rear side of the second slider as soon as the pedal is continued to be activated, the contact portion on the rear side of the second slider will be positioned further rearward of the first slider, separated by the minimum necessary gap.

[0042] On the other hand, at that time, the front block of the second slider is pressed against the swing arm tip block by pressing down on the pedal attached to it, so the set distance in this case is the distance between the contact point on the tip side of the second slider and the contact point on the rear end side of the second slider.

[0043] Therefore, if the rotation range of the crank rotation axis when the pedal is depressed is from the highest point to the lowest point, the distance between the abutment portion on the front end side of the second slider and the abutment portion on the rear end side of the second slider on the swing arm, which is kept to the minimum necessary length, is the longitudinal movement distance of the swing arm when the crank rotation axis on which the first slider is pivotally supported moves from the point farthest from the fixed swing fulcrum axis to the lowest point, i.e., the longitudinal width of the first slider plus the movement distance of the first slider in the latter part of the depression stroke. This provides a mechanism for ensuring that the first slider does not move far beyond the lowest point during a depression stroke starting from the highest point and ends at approximately the lowest point.

[0044] With this configuration, the pedal slides toward the tip along the swing arm during the pedal depression stroke, and slides toward the fixed rotation axis along the swing arm during the first part of the pedal return stroke, causing the pedal axis to trace a trajectory of a deformed elliptical circle with a large front-to-back width, a short front-to-back axis, and a long vertical axis.

[0045] However, although the distance traveled toward the rear end during the first stage of the return stroke and the bulge in the fore-and-aft width along the base line of the pedal axle circle locus are proportional to each other, they are not the same length. The bulge in the pedal axle width is primarily determined by the displacement of the pivot axis toward the base line when it pivots toward the rear end on the actual crank circle, and the maximum value of this displacement is the bulge in the same direction. Therefore, if the minimum required gap is assumed to be infinitesimal, the bulge in the fore-and-aft width of the pedal axle circle locus, which is the same as the bulge in the fore-and-aft width of the pivot axis toward the rear end, will naturally be approximately the radius of the actual crank circle.

[0046] For this reason, by appropriately setting the crank circle diameter to be used in practice relative to the comparative crank circle diameter described below, it is possible to make the overall front-to-rear width of the bulge of the pedal axle circle locus approximately the radius of a conventional normal crank circle, i.e., close to or greater than the normal crank arm length.

[0047] On the other hand, if the depression stroke is performed as described above from the so-called line-symmetric point of top dead center to bottom dead center on the crank circle, and the return stroke is performed from bottom dead center rearward of the lowest point to the line-symmetric point of top dead center, the movement distance of the first slider in the early part of the return stroke, which mainly determines the longitudinal fore-and-aft width of the corresponding pedal axis circle trajectory, is clearly smaller than the same movement distance when the depression stroke is from the highest point to the lowest point, and when the return stroke is from the lowest point to the highest point.

[0048] Therefore, this is the main reason why, in this configuration, it is desirable that the operating stroke be from the highest point to the lowest point, rather than from the point symmetrical to the top dead center to the bottom dead center, and that the return stroke be from the lowest point to the highest point.

[0049] The effect of this configuration is that the pedal itself moves vertically and longitudinally due to the swing of the swing arm, so that when the pedal is pressed down with the foot using the swing arm to rotate the crank arm, the pedal moves in a circular orbit that is easily adapted to the folding and pushing movements of the human leg, making it possible to pedal along a rotational orbit that reduces fatigue in the user's legs. This is the first effect of this configuration.

[0050] Next, the mechanism of rotational drive of this configuration is such that, of the left and right pedals, the first slider held by the crank arm near the highest point of the crank circle in the embodiment and held by the swing arm, for example, when the pedal attached to the second slider front block held by the swing arm is pressed down, the actuating force moves along a trajectory in the longitudinal direction of the swing arm, and the second slider front block that is located further towards the tip of the first slider and abuts it, and the pedal move together to the tip of the swing arm while maintaining the increased driving rotation moment due to a slight leverage effect, and the crank arm rotates around the crank shaft.

[0051] The pedal attached to the front block of the second slider moves to the end of its range of movement in the first stage of rotation until the crank arm is in the same direction as the line connecting the fixed swing fulcrum axis and the crank axis from the start of operation. During the remaining second stage of rotation of the crank arm's depression (operation) stroke, due to the direction of the operating force, the pedal remains at the end of the swing arm, and the crank rotating shaft is depressed to the lowest point of the actual crank circle, thereby increasing the driving rotation moment around the crank shaft due to the large leverage effect of the swing arm.

[0052] Furthermore, with this configuration as a whole, the efficiency of the rotational drive is improved by combining the pedal actuation force effect at least at the highest point, which is the positionally most important issue with conventional crank rotational drives, including and near the top point, and at least at the lowest point, which is the positionally most important issue with conventional crank rotational drives, including and near the bottom point, which is the positionally most important issue with conventional crank rotational drives.

[0053] [Correction based on Rule 91 19.03.2025] Therefore, by improving the efficiency of the rotation drive to almost the same level as that of a conventional fixed-fulcrum swing arm crank rotation drive system that does not have the approximately elliptical operating path of a pedal with a large front-to-rear width, in addition to the first effect mentioned above, the load of the rotation operation of the crank shaft when the user operates it using their leg strength can be greatly reduced, which is the second effect of this configuration.

[0054] Furthermore, when this configuration is actually used on a bicycle, rotational drive is relatively easy by manipulating the ankle direction and naturally moving the leg forward with the joint of the lower limb as the fulcrum, just like pushing down on the crank of a normal bicycle, and once the crank arm rotates and inertial force acts on the running body, continuous rotation is also easy, so the first and second effects can be enjoyed over a long period of time. On the other hand, the pedal-shift type rotational drive mechanism of this configuration is particularly effective when riding a bicycle on a long, gentle uphill road or other conditions where inertial force is not desirable.

[0055] In this way, when the actuation (push) direction is appropriately adjusted for an object that is actuated or pushed by a person's arms or legs, the features of this configuration can be maximized, leading to a wider range of uses, which is advantageous for this configuration. In addition, by effectively combining it with a mounting angle that is varied as viewed in the crankshaft direction, it can be applied to an even wider range of uses. On the other hand, even for objects that are not actuated by a person's arms or legs, this configuration can be similarly applied to many uses by combining an appropriately set actuation direction with a mounting angle that is varied as viewed in the crankshaft direction.

[0056] (Characteristic configuration) The pedal shift type crank rotation drive mechanism according to the present invention may comprise an elastic tension member having a tip-side abutment portion held by either the first slider or the second slider, and a tension abutment member having a tip-side abutment portion held by either the second slider or the first slider, in order to transmit a force that moves the second slider to the tip side in the longitudinal direction within its movable range while performing abutment contraction in response to the amount of reduction in the gap between the first slider and the second slider front block.

[0057] In this configuration, elastic tension members having tip-side abutment portions that come into or out of contact with either the tip-side abutment portion of the first slider or the tip-side abutment portion of the second slider are provided across the first slider and the second slider front block, primarily to form a tensioned state. For example, if the first slider is provided with an elastic tension member, the second slider front block is provided with a corresponding tension abutment member, with the tip-side abutment end of the elastic tension member becoming the tip-side abutment portion of the first slider and the rear-side abutment end of the tension abutment member becoming the tip-side abutment portion of the second slider, and both tip-side abutment portions coming into or out of contact with each other. Even in this case, the second slider tip-side abutment portion and the second slider rear-side abutment portion, which are the rear-side abutment ends of the tension abutment member in the longitudinal direction, are held on the swing arm facing each other with a predetermined distance between them, and the first slider tip-side abutment portion and the first slider rear-side abutment portion are held facing in opposite directions.

[0058] In this configuration, too, it is desirable that the operating stroke, which starts when one of the left and right pedals attached to the second slider front block is operated, be from the highest point to the lowest point, and the return stroke be from the lowest point to the highest point. The main reason for this is that this allows the front-to-rear width of the pedal axis circle locus to be increased, making it easier to adapt to the folding and sending-out movements of the legs, especially when stepping on them with the legs.

[0059] (Effects of the Invention) By configuring the operating stroke from the highest point to the lowest point and the return stroke from the lowest point to the highest point as in this configuration, the length of the swing arm is kept to a minimum while the elastic tension member is introduced, and at the start of pedal operation, for example when a person presses down on the pedal with their foot, the pedal position can be moved as far away as possible from the fixed swing fulcrum axis of the swing arm, making it possible to utilize the large leverage effect of the swing arm. Also, the driving rotation moment about the crankshaft generated by the operating force of the pedal from the beginning of depression, particularly the moment input to the crankshaft at and near the highest point, which normally corresponds to the top dead center of the crank, and at least at and near the lowest point, which normally corresponds to the bottom dead center of the crank, is increased. This is the first effect of the configuration that includes the elastic tension member.

[0060] As mentioned above, during one operation of the return stroke, the trajectory of the pedal shaft center suddenly changes direction just before the pedal is depressed. This occurs because there is no obstruction between the first slider S1 and the second slider front block S21, and the first slider S1 mechanically abuts against the abutment point on the tip of the second slider, which has been swinging on the swing arm, just before the end of the return stroke. The second advantage of this characteristic configuration is that by introducing an elastic tension member to create a tensioned state, the timing of this abutment and the transmission of the moving force from the first slider to the second slider are accelerated, while the elastic tension member absorbs and reduces the force transmitted, resulting in smooth pedal movement and a gentle pedal shaft center trajectory.

[0061] [Correction based on Rule 91 19.03.2025] Exploded perspective view showing the appearance of the pedal shift type crank rotation drive mechanism according to the first embodiment Exploded perspective view showing the main parts of the pedal shift type crank rotation drive mechanism Explanatory diagram showing the pedal trajectory of the pedal shift type crank rotation drive mechanism Explanatory diagram of the operation mode of the pedal shift type crank rotation drive mechanism Explanatory diagram of the operation mode of the main parts of the pedal shift type crank rotation drive mechanism Explanatory diagram showing the operating force of the crank pedal Perspective view showing the main parts of the pedal shift type crank rotation drive mechanism according to the first embodiment Explanatory diagram showing the pedal trajectory of the first embodiment Explanatory diagram of the operation mode of the pedal shift type crank rotation drive mechanism according to the first embodiment Perspective view showing the main parts of the pedal shift type crank rotation drive mechanism according to the second embodiment Explanatory diagram showing the pedal trajectory of the second embodiment Explanatory diagram of the operation mode of the pedal shift type crank rotation drive mechanism according to the second embodiment

[0062] [First embodiment] (overview)

[0063] 1 to 9, the basic technical content of the present invention relates to a pedal-shift-type crank rotation drive mechanism Z that includes a pair of left and right crank arms CA and a crank pivot axis CX2, a pair of left and right swing arms A journaled on a fixed swing fulcrum axis A4 located at a distance from the crank axis CX1 that exceeds the length of the crank arms CA, a first slider S1 journaled on the crank pivot axis CX2 and reciprocating along the longitudinal direction of the swing arms A, a second slider S2 that comes into contact with or is not in contact with the first slider S1 and moves back and forth intermittently in the same direction within its movable range as the first slider S1 reciprocates, and a pedal P attached to a second slider front block S21 that swings the swing arm A to rotate the crank axis CX1 while tracing a substantially elliptical locus, and that provides a rotational output to an output unit 5 that rotates integrally with the crank axis CX1. The present invention simultaneously achieves the following two main objectives.

[0064] The first objective is to create a mechanism that significantly improves the rotational drive efficiency of pedal operation at least at the so-called top dead center and bottom dead center, and in the vicinity of the top dead center and bottom dead center, when a pedal P, which is rotatably attached to the pedal shaft of a normal crank, is depressed.

[0065] The second purpose is to make the pedal P operate in a circular orbit that is more adaptable to the folding and pushing movements of a person's legs, rather than in a reciprocating swinging motion in the same orbit.

[0066] To achieve these two goals simultaneously, the present invention specifically makes the forward and backward movement of the pedal P smaller than a human walking step, but is made to match the movement of the human leg as much as possible, and makes the path of the pedal axis PX a roughly elliptical path circle with a vertically longer axis, thereby reducing the power burden of repeated pedaling. For example, the purpose of this invention is to reduce the burden on the hip joints and other parts of the body when operating the pedal P with the human leg, and to enable smooth, continuous operation.

[0067] An embodiment of the present invention when used on a bicycle will first be described with reference to Figures 1 to 6. However, to make the following description easier to understand, the figures show an example (hereinafter referred to as this example) in which the pedal axis PX is at the tip of the swing arm A from the start of pedal depression due to the function of the pushing leg and the swinging tension member 3, for example.

[0068] A crankshaft CX1 is supported on a bicycle frame F, and is equipped with a pair of crank arms CA, a crank pivot axis CX2 (corresponding to the pedal axis of a normal bicycle), and pedals P, which are positioned on the left and right sides with a phase angle difference of 180 degrees. Rotational drive of both crank pivot axes CX2 around the crankshaft CX1 rotates the crankshaft CX1, and the resulting output rotates the wheel. In this example, a crank mechanism with a pair of crank arms CA and crank pivot axis CX2, each of which has a predetermined length shorter than that of a normal bicycle, is used. As mentioned above, this is called the "used crank," and the rotational locus of the crank pivot axis CX2a is called the "used crank circle."

[0069] This embodiment has a fixed swing fulcrum axis A4 at a position that is greater than the length from the crank axis CX1 of the crank to the crank arm CA, and a pair of left and right swing arms A that swing back and forth by a predetermined angle are provided, and a first slider S1 that moves back and forth relatively along a track set in the longitudinal direction is rotatably engaged with the crank rotation axis CX2 of the embodiment via a sleeve S11 or the like.

[0070] Here, the first embodiment will be referred to as the present first embodiment. In this first embodiment, in order to provide rigidity to the second slider S2 that moves back and forth relatively to the swing arm A along the same trajectory as the trajectory of the first slider S1 provided in the longitudinal direction of the swing arm A, a second slider front block S21 and a second slider rear block S22 that is held by the swing arm A are provided at a predetermined distance apart from the second slider S21 that is the distance that the first slider S1 moves in the longitudinal direction.

[0071] On the other hand, the first slider S1 and the second slider S2 each have one tip-side contact portion. That is, the first slider tip-side contact portion S1f is provided on the tip-side contact surface of the first slider S1 in the tip-side direction, and the second slider tip-side contact portion S2f is provided on the rear-end contact surface of the second slider front block S21.

[0072] The rear end surface of the first slider S1 is the first slider rear end contact portion S1r, and the front end surface of the second slider rear block S22 is the second slider rear end contact portion S2r. The first slider front end contact portion S1f and the first slider rear end contact portion S1r are held facing opposite directions in the longitudinal direction, and the second slider front end contact portion S2f of the second slider front block S21 and the second slider rear end contact portion S2r of the second slider rear block S22 are held by the swing arm A facing each other with a predetermined gap between them. In a pair of left and right second sliders S2 having a bifurcated structure with a second slider front block S21 and a second slider rear block S22 connected by a connecting member 21 so as to straddle the first slider S1, a pedal shaft P10 and a rotatable pedal P are attached to the second slider front block S21 on the tip side, and by alternately stepping on the left and right pedals P, the crank arm CA and the crank rotation axis CX2a are caused to rotate in a direction from the highest point to the lowest point via the aforementioned intermediate point.

[0073] [Correction under Rule 91 19.03.2025] In addition, as shown in Figure 3 or Figure 6, in this embodiment, the range of the operating stroke in which one pedal P performs the depressing action is set to be from the highest point PH to the lowest point PL on the locus of the crank rotation axis CX1a, and the range of the return stroke in which the other pedal P performs the return action is set to be from the lowest point PL to the highest point PH.

[0074] One reason for this setting is based on the reliability of the pedal P depression action. In other words, the bottom dead center is the point of contact with the actual crank circle on the lower tangent drawn from the fixed swing fulcrum axis AX to the actual crank circle, so the positional fluctuation range of the swing arm A relative to the swing contact angle is large, and this is likely to be uncertain due to variations in the operation of the pedal P. On the other hand, the lowest point PL allows the pedal P to accurately complete its operating stroke. Another reason, as mentioned above, is that by doing so, the front-to-rear width of the circular locus of the pedal axis PX can be increased, making it easier to adapt to the folding and pushing movements of the legs, especially when stepping on them with a human leg.

[0075] In an embodiment used on a bicycle, the pair of left and right crank arms CA and crank rotation axis CX2 are used, and the depression stroke is the journey from the depression start point at approximately the top point of the crank circle (positionally equivalent to the top dead center of a normal crank) to the depression end point at approximately the bottom point (also positionally equivalent to the bottom dead center), and the return stroke before the depression stroke is from the end point to the start point, and the return stroke is performed by the depression strokes on the opposing sides.

[0076] The rotational drive mechanism of the present invention to achieve the first object is such that the first slider S1 is held by a pair of left and right oscillating arms A journaled on a fixed oscillating fulcrum axis A4 located at a distance from the crank axis CX1 beyond the length of the crank arm CA, and at the same time is held by the crank arm CA located near the highest point of the crank circle in the practical application, and when the pedal P attached to the second slider front block S21, which is always held by the oscillating arm A at a position further tip than the first slider S1, is depressed, for example, when the pedal depression force is directed in the direction of a reference line connecting the highest point PH to the lowest point PL on the practical application crank circle, the depression force generated can improve the rotational drive efficiency at least at the highest point PH and the lowest point PL, which correspond in position to the so-called top dead center and bottom dead center of a normal crank, and near the highest point PH and the lowest point PL.

[0077] Here, in comparison with the driving rotation moment of a normal crank, the configuration of this embodiment (hereinafter simply referred to as "this configuration") makes it possible to depress the pedal P completely avoiding the so-called top dead center and bottom dead center, and in addition to the effect of the generated depressing force, the swing arm A has a larger leverage effect than a normal crank, so that the driving rotation moment around the crank axis CX1 of this configuration exceeds the driving rotation moment of a normal crank in the range from the highest point PH to the lowest point PL.

[0078] Next, the configuration of the first embodiment that is provided for the second purpose will be described. Details of each part of the basic pedal shift type crank rotation drive mechanism Z (hereinafter simply referred to as "the mechanism Z") according to the first embodiment will be described again with reference to Figures 1 to 6 of this example.

[0079] As shown in Figure 1, this mechanism Z has pedals P attached to swing arms A that are linked to a crankshaft CX1 and a crank rotation axis CX2, and the swing arms A are swung back and forth by alternately stepping on the left and right pedals P. The pedals P are configured to be able to move back and forth along the swing arms A.

[0080] 3 and 4, during the depression (actuation) stroke from the highest point PH to the lowest point PL by depressing the pedal P, that is, while the pedal axis center PX moves from point F to point H in Fig. 3, only the first slider S1 moves back and forth toward the tip of the swing arm A, completing the actuation stroke. That is, one pedal P and the second slider S2 are held at positions on the tip side of the swing arm A while maintaining the longest possible distance from the fixed swing fulcrum axis A4, and together with the swing of the swing arm A, the pedal axis center PX describes an arc-like curved locus centered on the fixed swing fulcrum axis A4 and with the distance to the pedal axis center PX as the radius.

[0081] When the pedal P on one of the swing arms A is depressed, the other swing arm A rises. When the crank arm CA rotates a quarter turn in the first half of the return stroke of the other crank pivot axis CX2, the first slider S1 on that side abuts against the second slider rear block S22, and the second slider S2 is returned toward the fixed swing fulcrum axis A4, so that the other pedal P is pulled back toward the fixed swing fulcrum axis A4 and then moves toward the tip of the swing arm A in the subsequent second half of the quarter turn. As shown in Figure 3, the movement locus of the pedal axis center PX when viewed along the crank axis CX1, in conjunction with the swing of the swing arm A, is a roughly oval arc shape that is vertically symmetrical and bulges toward the rear end by approximately the radius of the crank circle in practice, i.e., the arm length of the crank in practice.

[0082] In this embodiment, as described above, by appropriately setting the crank circle diameter, the depression (operation) stroke and return stroke are synchronized, and the rotational locus of the pedal axis PX when the crank rotation axis CX2a rotates through one cycle, in combination with the swing of the swing arm A, becomes a modified oval shape with a large forward and backward movement range not found in conventional fixed-fulcrum swing arm crank rotation drive systems, that is, a curved circular arc with a slight bulge toward the tip of the swing arm A and a modified oval arc with a bulge toward the rear end by approximately the radius of the crank circle used in the embodiment, together with a bulge close to the crank arm length of a normal crank, which is easily adapted to the folding and pushing movements of a person's legs. This is the basic configuration of the first embodiment, which is provided to achieve the second objective.

[0083] When operating the pedal P, the movement method and range of motion that can withstand prolonged pedaling motion, for example, of a person's legs, are limited. Therefore, in the case of pedal operation using a typical crank, the length of the crank arm is appropriately set depending on the user and the conditions of use. In contrast, in this mechanism Z, to achieve a compact device, the distance from the crank axis CX1a to the crank rotation axis CX2a, i.e., the arm length of the crank used in the practical application, is set to a length equal to or shorter than the length of each crank arm appropriately set for a typical crank. Therefore, the arm length of the crank used in the practical application is also appropriately set depending on the user and the conditions of use, and the travel range of the first slider, which is equal to the crank circle diameter, is also the same. In this case, the rotational locus of the crank rotation axis corresponding to the appropriately set normal crank arm is referred to herein as the comparative crank circle.

[0084] Figure 3 compares the trajectory T1 of the crank circle of the present example, based on the crank rotation axis CX2a, with the trajectory T2 of the comparative crank circle based on a normal crank rotation. As mentioned above, the crank circle of the present example is necessarily smaller than the comparative crank circle. While it is naturally smaller than a human walking step, it is preferable to have a front-to-rear width that is as close as possible to the user's leg folding and forward movement. The trajectory of the pedal axis PX is also shown in this figure. The rotation trajectory of the pedal axis PX as the crank rotation axis CX2 makes one revolution is slightly shifted forward from the circular trajectory of the crank rotation axis CX2a.

[0085] [Correction based on Rule 91, 19.03.2025] Figure 6 illustrates the relationship between the pedal P depression force and the driving rotational moment around the crank axis CX1 generated on the locus T1 (practical crank circle) of the crank rotation axis CX2a in this example. Assume that the direction of the pedal P depression force Fa is, for example, the direction of a line (reference line) connecting the highest point PH and the lowest point PL of the rotation locus of the crank rotation axis CX2a. The force acting at the intersection P1 of the locus T1 and a line passing through the crank axis CX1a and forming an arbitrary angle θ with the reference line is defined. In this case, the angle formed by the center line of the swing arm A and the line connecting the fixed swing fulcrum axis AX and the crank axis CX1a is defined as α.

[0086] Because a downward depression force Fa acts on the pedal axis PX, the pedal depression force component Fm1 perpendicular to the swing arm A at the pedal axis PX is Fa·cos α. Based on this Fm1, a force k·Fm1, i.e., k·Fa·cos α, acts parallel to Fm1 at the intersection P1. k is the leverage ratio expressed as L2 (length of line segment AX-PX) / L1 (length of line segment AX-P1). Furthermore, the force acting in a direction tangent to the locus T1 at the intersection P1 is k·Fa·cos α·sin(θ+α).

[0087] Here, if r1 is the radius of locus T1 and r2 is the radius of locus T2, the driving rotation moment Ma1 about the crankshaft CX1 at intersection P1 is expressed as follows: Ma1 = k r1 Fa cos α sin(θ + α) (1) When θ is zero, that is, the basic included angle formed by line segment AX-CX1a and line segment AX-PH is defined as α0. As θ increases from 0 degrees to 90 degrees, L1 increases, but conversely, α decreases from α0 to 0 degrees.

[0088] α0 is determined by the relationship between the fixed swing fulcrum axis AX and the trajectory T1, but taking into consideration the length of the swing arm A, the size of the element members, the stepping position, height, stroke, etc., it is desirable for α0 to be between 20 degrees and 35 degrees, and an effective angle is around 25 degrees to 30 degrees.

[0089] In this example, where the pedal P is shifted to the maximum extent possible from the depression start point to the tip position of the swing arm A, L2 is constant during the depression stroke of the pedal P, that is, the region where the crank pivot axis CX2a moves from the highest point PH to the lowest point PL, so the leverage ratio k = (L2 / L1) is maximum at the highest point PH and the lowest point PL. When the crank pivot axis CX2a is at the highest point PH or the lowest point PL, the pedal P is at the very tip of the swing arm A, so a larger rotational moment can be applied to the crank arm CA than at the beginning of the depression stroke.

[0090] In other words, with the pedal shift type rotary drive mechanism Z of this example, the leverage ratio k increases the closer it is to the highest point PH and the lowest point PL, which normally correspond to the top dead center and bottom dead center of the crank, and the drive rotation moment also increases due to the leverage effect caused by this leverage, making it a rational means that is well suited to the pedal depression operating force component.

[0091] Furthermore, the change in the driving rotational moment about the crank axis CX1a in the second half of the pedal depression stroke, when θ passes through the midpoint of 90 degrees and reaches the lowest point PL of 180 degrees, is symmetrical above and below the line segment AX-CX1a, and the improvement in the driving rotational moment about the crank axis CX1 throughout the entire pedal depression stroke is approximately twice that achieved up to the midpoint of 90 degrees.

[0092] So far, we have explained this example in which the pedal axis PX is located at the tip position of the swing arm A from the start point of pedal depression. However, in the original first embodiment with the configuration shown in Figure 7, the pedal P is attached to the second slider front block S21 having the second slider tip side abutment portion S2f in a state of abutting against the first slider tip side abutment portion S1f at the start point of operation, and is maintained at the tip side of the swing arm. In this state, the pedal P is operated to rotate the swing arm A, moving the first slider S1 via the crank rotation axis CX2 and moving the entire second slider S2 until it is closest to the swing arm tip block A1, which is the tip of the moving range on the swing arm A. In other words, L2 is not constant in the first half of the depression stroke, but changes with θ, just like L1. When θ is 0 degrees, that is, at the top of the crank circle used in the embodiment, L2 is at its minimum, the leverage ratio k = (L2 / L1) is not at its maximum, and the change in the driving rotational moment around the crank axis CX1 is not symmetrical above and below the base line passing through the fixed oscillating fulcrum axis AX and the crank axis CX1a in the first and second halves of the depression stroke.

[0093] However, in this case, until θ is 90 degrees, the pedal P gradually approaches the tip of the swing arm A, and L2 becomes maximum when θ is at a position on the base line at 90 degrees, and in the first half of the stroke, the leverage ratio k is insufficient but at least exceeds 1, so the leverage effect remains, and in the second half of the stroke when θ exceeds 90 degrees, the pedal P is positioned at the very tip of the upper movable range of the swing arm A with the pedal actuation force still applied, and L2 becomes a constant length at its longest, and the driving torque near the lowest point increases significantly as L1 decreases. Therefore, even in this case, the effect of improving the driving torque about the crankshaft CX1 throughout the pedal actuation stroke, along with the pedal actuation force, is exerted.

[0094] (Crank Arms) As shown in Figure 1, a pair of left and right crank arms CA are attached to a frame F of a bicycle or the like. The left and right crank arms CA extend radially from a crankshaft CX1 with a phase angle difference of 180 degrees. A sprocket 50 is attached to the crankshaft CX1 as an output unit 5 that transmits the rotation of the crankshaft CX1 to, for example, a rear wheel. A crank rotation axis CX2 extends outward from the tip of each of the left and right crank arms CA, parallel to the crankshaft CX1.

[0095] (Swing Arm) A fixed swing fulcrum shaft A4, which is different from the crank shaft CX1, is provided on the frame F at a position that is longer than the length of the crank arm CA, and the swing arm A is rotatably supported on this fixed swing fulcrum shaft A4. The fixed swing fulcrum shaft A4 is provided, for example, on the same base line as the crank shaft CX1 and on the rear end side. The first slider S1, second slider S2, and pedal P are held by this swing arm A.

[0096] 1 and 2, a first slider S1 is rotatably attached to the crank rotation axis CX2 of the crank arm CA via a bearing S11 or the like. The first slider S1 is fitted onto two guide bars A3 provided on the swing arm A as a track via linear bearings or the like. This allows the first slider S1 to smoothly reciprocate on the swing arm A in accordance with the rotation of the crank arm CA.

[0097] (Second slider) The second slider S2, which follows the reciprocating movement of the first slider S1, is attached to the two guide bars A3 of the swing arm A so as to be able to move back and forth, also via linear bearings or the like. The second slider S2 is made up of a second slider front block S21 and a second slider rear block S22, which are connected in a bifurcated manner by a connecting member 21. A pedal P is journalled on the second slider front block S21.

[0098] (Pedal) The rotatable pedal P is attached to the second slider front block S21 of the second slider S2 at a position where it does not interfere with the first slider S1 or the swing arm A.

[0099] 7 and 9, the pedal-shift-type crank rotation drive mechanism Z of the first embodiment has no obstacle to movement between the first slider S1 and the second slider front block S21, allowing the relative positional relationship between them to be easily changed. Therefore, to facilitate the second slider S2, which holds the pedal P, sliding (or shifting) forward of the swing arm A as much as possible when the pedal P is depressed, the fixed swing fulcrum axis AX is tilted upward with respect to the crank axis CX1a. That is, the base line on the fixed swing fulcrum axis A4 side is tilted by an appropriate angle β from the horizontal toward the highest point PH around the crank axis CX1a, not the fixed swing fulcrum axis AX, without changing the correlation between the base line and the entire configuration. That is, the angle is tilted when viewed from the crank axis CX1.

[0100] In this way, when the pedal P is depressed in the early stage of the depression stroke, the first slider S1 is moved via the swing arm A and the crank pivot axis CX2, and the entire second slider S2 is moved until it abuts against the swing arm tip block A1, the pedal axis PX, in conjunction with the swing of the swing arm, traces a curved trajectory that bulges downward toward the tip.

[0101] Then, in the remaining latter stage of the depression stroke, which is the first half of the rotation of the crank arm CA, only the first slider moves toward the fixed swing fulcrum axis A4 according to the trajectory of the crank circle until the crank rotation axis CX2a reaches the lowest point PL, that is, from point G to point H in Figures 8 and 9, but the pedal P attached to the second slider front block S21 remains in contact with the swing arm tip block A1 due to the opposing directions of the operating forces, and the moment the first slider rear end abutment portion S1r abuts the second slider rear end abutment portion S2r, operation is prevented, and the depression stroke ends. As a result, the pedal axis PX, in conjunction with the swing of the swing arm A, describes a partial arc trajectory whose radius is the distance from the fixed swing fulcrum axis AX to the pedal axis PX. At this time, until the axis CX2a of the crank pivot shaft CX2 that supports the first slider S1 reaches the lowest point PL, the rear end abutment portion S1r of the first slider, i.e., the rear end face, comes closest to the rear end abutment portion S2r of the second slider without coming into contact with it.

[0102] However, when the crank rotation axis CX2a caused by one pedal P being depressed during the depression stroke passes the lowest point PL toward the bottom dead center due to inertia or the like, and the crank arm CA tries to rotate further, the first slider S1 on that side immediately comes into contact with the rear end abutment portion S2r of the second slider, preventing the crank arm CA from rotating any further, and the depression stroke is completed without the axis CX2a of the crank rotation axis CX2 on which the first slider S1 is pivotally supported moving significantly beyond the lowest point PL. Then, when the other pedal P is subsequently depressed, the return stroke of the crank rotation axis CX2a on that side begins, and with the rear end abutment portion S1r of the first slider in contact with the rear end abutment portion S2r of the second slider, both begin their return stroke toward the rear end of the swing arm A, and the pedal P is pulled back toward the fixed swing fulcrum axis A4.

[0103] That is, at the same time, the other pedal P is depressed to start the depression stroke, and the other crank rotation axis CX2a passes the highest point PH, and the first slider S1 abuts against the abutment portion S2f on the tip side of the second slider, and the depression stroke is started so that the other pedal P is pushed toward the tip side of the swing arm A.

[0104] On the other hand, the return stroke in which the pedal P returns is as follows: In the first part of the return stroke, when one pedal P rotates the crank arm CA during the return stroke by depressing the opposing pedal P, the crank arm CA rotates upward from the lowest point PL, which is the end point of the depression in the crank circle in the embodiment, to a line passing through the fixed swing fulcrum axis AX and the crank axis CX1a of the swing arm A, immediately after the start of the return stroke, the first slider rear-end abutment site S1r, i.e., the rear end face, moving rearward on the swing arm A abuts the second slider rear-end abutment site S2r, and the entire second slider S2 moves toward the fixed swing fulcrum axis A4 to its closest position without abutting the rear-end block A2 on the fixed swing fulcrum axis A4 side of the swing arm A. Accordingly, the pedal P attached to the second slider front block S21 also moves closest to the fixed swing fulcrum axis A4 by the same distance. As a result, as described above, the pedal axis PX, in conjunction with the swing of the swing arm A, describes an arc of about a quarter modified ellipse that bulges out toward the rear end of the base line by approximately the radius of the crank circle employed.

[0105] In the latter part of the return stroke in which the crank arm CA continues to rotate up to the highest point PH, only the first slider S1 moves to the tip side of the swing arm A based on the trajectory of the crank circle, ideally so that the tip abutment portion S1f of the first slider, i.e., the tip end face, comes closest to the tip abutment portion S2f of the second slider front block S21, i.e., the rear end face, without coming into contact with it, and ends the return stroke.

[0106] However, during that time, that is, in the latter part of the return stroke, the second slider S2 remains stopped in the longitudinal direction of the swing arm A, and therefore, in conjunction with the swing of the swing arm A, the pedal axis PX of the pedal P attached to the second slider front block S21 describes a partial arc curved locus pointing upward in the rear direction, with the radius being the distance from the fixed swing fulcrum axis A4 to the pedal axis PX.

[0107] In this case, as mentioned above, just before reaching the highest point PH in the latter part of the return stroke, the first slider S1 moving to the tip side comes into direct contact with the second slider front block S21 swinging upward, causing a sudden change in direction in the trajectory of the pedal axis PX, resulting in an uneven section. While this is not desirable for pedal movement, it provides a good opportunity to time the subsequent pedal depression in use.

[0108] In this configuration, the first slider S1, which is supported on the crank rotation axis CX2, performs continuous sliding back and forth movement, but the second slider front block S21, to which the pedal P is attached, has a simple mechanism in which it moves passively and intermittently along the swing arm A only by contact with the first slider S1, and yet the pedal P can perform both sliding and rotational movements.

[0109] The first effect of this configuration is that, as shown in Figure 8, the pedal axis PX, in combination with the swing of the swing arm A, expands overall in both directions by more than the radius of the crank circle used in the practical application, or by approximately the normal crank arm length depending on the setting of the crank circle diameter used in the practical application, and describes a deformed elliptical circular locus with a vertically longer diameter that is slightly inclined toward the tip end of the swing arm A in the longitudinal direction.When using the swing arm A to step on the pedal P with the leg and operate and rotate the crank arm CA, the movement of the pedal follows a circular locus that is easily adapted to the folding and pushing movements of the person's leg, and pedaling can be performed in a way that reduces fatigue in the operator's legs.

[0110] A second effect of this configuration is that the highest point PH and lowest point PL are approximately the start and end points of the depression stroke, making it possible to depression that completely avoids top dead center and bottom dead center.The overall operating force generated by depression, and particularly the large leverage action of swing arm A in the remaining latter rotation of the depression stroke, improve the efficiency of rotational drive, which has been the biggest problem with conventional crank rotational drives, at least at and near the highest point PH, which is usually equivalent to the top dead center of a crank, and at least at and near the lowest point PL, which is usually equivalent to the bottom dead center of a crank.

[0111] Furthermore, when the direction of operation (push) is appropriately adjusted for a device that is operated or depressed by a person's arms or legs, the features of this configuration can be maximized, leading to a wider range of uses, which is advantageous for this configuration. In addition, by appropriately tilting the device, i.e., by mounting it at an angle as viewed from the crankshaft CX1, it can be applied to a wide range of applications. On the other hand, the device of this configuration can also be effectively used in devices that are not operated by a person.

[0112] [Correction based on Rule 91 19.03.2025] (Second Embodiment) Here, the second embodiment will be referred to as the present second embodiment. Based on Figures 10 to 12, the basic characteristic configuration of this second embodiment is that, in addition to the configuration of the first embodiment, the second embodiment includes an elastic tension member having a tip-side abutment portion extending across the first slider S1 and the second slider front block S21, primarily for forming a tensioned state. Therefore, the basic configuration and basic operating mode are no different from the configuration of the first embodiment, which corresponds to claim 1 of the present invention.

[0113] Furthermore, in implementing the second embodiment, the emphasis is placed on slightly lowering the lowest position of the pedal axle P10 that is depressed within the vertical range of movement of the person's leg, while also lowering the highest position by the same amount to keep the height down. Therefore, again, for the reason that the fore-and-aft width of the pedal axle circle path can be increased as described above, the rotation range of the crank rotation axis CX2a when the pedal P is depressed is set to be from the highest point PH to the lowest point PL, and the base line on the fixed oscillation fulcrum axis A4 side is deflected by an appropriate angle β from the horizontal toward the highest point PH around the crank axis CX1a, not the fixed oscillation fulcrum axis AX, without changing the correlation between the base line and the entire configuration, that is, the pedal is mounted deflected by the angle β when viewed from the crank axis CX1 direction.

[0114] However, even in this case, as explained in the first embodiment, if there is no obstacle to maintain a gap between the first slider tip end contact point S1f and the second slider tip end contact point S2f, sufficient leverage effect is not generated near approximately the highest point PH at the start of depression, resulting in an insufficient increase in the driving rotational moment around the crankshaft CX1 and an insufficient improvement in the efficiency of the rotational drive, and in the trajectory of the pedal axis center PX during one operation of the return stroke, there is a point where the direction of travel of the pedal P suddenly changes near the top dead center just before depression.

[0115] The effect achieved by this second embodiment is to improve the sudden change in the trajectory direction of the pedal axis PX, and to move the pedal P as far as possible toward the tip end from the fixed swing fulcrum axis AX of the first slider S1 and the swing arm A when starting to press down on the pedal P, thereby increasing the driving rotational moment around the crank axis CX1 when pressing down on the pedal P and improving the efficiency of the rotational drive.

[0116] Based on the second prerequisite mentioned above as a characteristic constituent element of the mechanism Z according to the present invention, the most desirable basic narrow angle and the crank circle diameter to be used are set, and the longitudinal dimensions of the first slider S1 and the second slider front block S21, such as an appropriate gap, are set, and the minimum required length of the swing arm A is uniquely determined. Therefore, for example, if it is possible to reduce the distance between the fixed swing fulcrum axis AX and the crank axis CX1a without changing the practically necessary minimum length of the swing arm A, slightly increase the basic narrow angle set with a certain degree of flexibility, or conversely widen the distance between the first slider S1 and the second slider front block S21 when they are closest to each other to provide a space greater than the shortest contracted length of the elastic tension member N for forming the tensioned state, then it is of course possible to extrapolate the guide bar A3 into that space, hold an elastic tension member N of its shortest contracted length, one of whose end faces doubles as the tip-side abutment portion, and provide one of the end faces of the first slider S1 or the second slider front block S21 with the function of a tension abutment member Nt. Even in this case, the operation, action, and effects obtained are no different from those of the second embodiment, which has the same concept of providing elastic tension members on both the first slider S1 and the second slider front block S21, as described below.

[0117] However, in the second embodiment described here, in cases where it is not permitted to change the set most desirable basic narrow angle and it is not possible to provide space for inserting an elastic tension member N of its shortest contracted length into the gap between the first slider S1 and the second slider front block S21 when they are closest to each other, the elastic tension member N is not placed between the first slider S1 and the second slider front block S21 as shown in Figure 10, but is shifted to a position such as below the swing arm A and attached to the first slider S1 or the second slider front block S21, and the corresponding tension abutment member Nt is attached to the second slider front block S21 or the first slider S1, respectively.

[0118] For example, as shown in Figure 10, if an elastic tension member N is provided on the first slider S1, with its tip end portion serving as the first slider tip end abutment portion S1f, and a tension abutment member Nt is provided on the second slider front block S21, with its rear end portion serving as the second slider tip end abutment portion S2f, the second slider tip end abutment portion S2f and the second slider rear end abutment portion S2r on the tension abutment member Nt will be held by the swing arm A facing each other with a predetermined gap between them.

[0119] With this configuration, when the first slider S1 and the second slider front block S21 approach each other in the latter part of the return stroke, the first slider tip side abutment portion S1f of the elastic tension member N and the second slider tip side abutment portion S2f of the tension abutment member Nt come into contact in response to the amount of reduction in the gap between them, causing the elastic tension member N to contract. At that time, a pushing force is transmitted from the first slider S1 to the second slider front block S21, and at the start of the pedal P's depression stroke, the pedal P is moved even slightly toward the tip of the swing arm A. As a result, compared to a system without an elastic tension member N, the driving rotation moment due to the leverage effect is increased near the highest point PH, improving rotational drive efficiency.

[0120] [Correction under Rule 91 19.03.2025] In addition to mitigating the sudden change in the direction of the trajectory of the pedal P before the end of the return stroke, as shown in Figure 11, the operating trajectory of the pedal axis PX can be made to bulge slightly towards the tip of the swing arm A and towards the rear end by the radius of the crank circle used, resulting in a smooth, curved circle with an overall width close to or greater than the length of the crank arm of a normal crank, a short diameter in the front-to-back direction, and a long diameter in the vertical direction, and a nearly symmetrical, approximately oval shape.

[0121] In the second embodiment, the elastic tension member N comprises a compression coil spring N1, a spring holding shaft N2 into which the compression coil spring N1 is inserted and held, and a tension bearing member N4 having a bearing hole N3 that supports the spring holding shaft N2 so that the spring holding shaft N2 can slide in the longitudinal direction. Meanwhile, the tension abutment member Nt that abuts against the tip end of the spring holding shaft N2 to receive the biasing force of the compression coil spring N1 is attached to the second slider front block S21, and its rear end in the longitudinal direction forms the second slider tip-side abutment portion S2f.

[0122] The end of the spring holder shaft N2 facing the tension abutment member Nt is flange-shaped and serves as an extended abutment for the compression coil spring N1, also serving as the first slider tip-side abutment portion S1f. The opposite end is threaded, and a double lock nut N5 or similar prevents the spring holder shaft N2 from slipping out of the tension bearing member N4 due to the biasing force of the compression coil spring N1. This double lock nut N5 also serves to adjust the length of the spring holder shaft N2 protruding from the tension bearing member N4.

[0123] This adjustment makes it possible to determine the timing at which the tip of the spring holding shaft N2 contacts the tension contact member Nt during the latter half of the return stroke of one pedal P. Of course, the tip of the spring holding shaft N2 may be brought into contact with the tension contact member Nt and the biasing force of the compression coil spring N1 may be applied from the very beginning of the latter half of the return stroke of the pedal P.

[0124] The compression coil spring N1, spring holding shaft N2, tension bearing member N4, tension abutment member Nt, etc. are attached to the first slider S1 and the second slider front block S21, respectively, so as to be located below the swing arm A. In this case, a step N4a is provided in the tension bearing member N4, and a space is provided in which the compression coil spring N1 in a compressed state can be held even when the first slider S1 and the second slider front block S21 abut against each other.

[0125] In one embodiment of the compression coil spring N1, the difference in length between when unloaded and when compressed is large, and in the latter half of the return stroke of one pedal P due to depression of the other pedal P, the spring holding shaft N2 abuts against the tension abutment member Nt provided on the second slider front block S21 to which the pedal P is attached, and has a spring force that moves the entire second slider S2 as far as possible toward the tip of the swing arm A.

[0126] The movement of the second slider S2 may begin with a slight delay from the movement of the abutting first slider S1, but the movement will occur if the compression coil spring N1 continues to transmit the force that moves the second slider S2.

[0127] In the second embodiment, as described above, the pedal P is moved closer to the tip of the swing arm A, and compared to the case where there is no elastic tension member N, when the rotational drive starts, the second slider front block S21 has already moved, for example, about half the travel distance of the first stage of the depression (operation) stroke towards the tip, and the depression stroke continues when the pedal P attached to it is depressed.

[0128] In this case, for example, when one of the pedals P is depressed with the foot (points F to H in Figures 11 and 12), the tensioned state is not released, so in the first half of the depression, the compression coil spring N1 initially contracts against the movement resistance of the second slider front block S21, such as the depression force, and finally due to the movement propulsion force of the first slider S1 against the second slider front block S21, which comes to a stop by abutting against the swing arm tip block A1, and an extra operating force is required to cope with this reaction force.

[0129] In the second half of the cycle, all of the contraction is released and the compression coil spring N1 expands to its original unloaded length, completing one cycle of expansion and contraction. However, the energy generated by depressing the pedal P to compress the spring during this cycle is basically used to rotate the crank in the second half of the cycle, so no energy loss occurs in the crank operation of the mechanism Z.

[0130] On the other hand, if the pedal is not mounted at an angle when viewed from the crank axis CX1 direction at the start of the depression (operation) stroke, the narrow angle formed by the line passing through the line segment AX-CX1a and the line passing through the line segment AX-PH shown in Figure 11 is an upward elevation angle depending on the direction of depression, so that the compression coil spring N1 is contracted by the depression force in the opposite direction, and the second slider front block S21 and pedal P may momentarily move backward toward the rear end on the swing arm A, and then be immediately pushed by the first slider S1 and begin to move toward the tip end.

[0131] However, in the second embodiment, as shown in FIG. 11, the fixed fulcrum axis A4 side of the extension line passing through the fixed fulcrum axis AX and the crank axis CX1a, i.e., the rear end side, is attached to the frame F or the like at an appropriate angle β from the horizontal toward the highest point with the crank axis CX1a as the center, so that momentary backward movement of the pedal P is almost completely eliminated.

[0132] Another advantage of this configuration, which is achieved by attaching the pedal to a frame F or the like with the rear end tilted upward and the front end tilted downward by an angle β, is that, as mentioned above, the lowest position of the pedal shaft P10 that is stepped on within the vertical range of movement of the person's leg is slightly lowered, while the highest position is also lowered by the same amount, thereby reducing the height and significantly reducing the strain caused by repeated pedaling operations.

[0133] The pedal-shift crank rotation drive mechanism of the present invention can be used in a wide range of devices, including not only ordinary bicycles but also recumbent bicycles, tricycles for physically disabled people or for commercial use, fitness equipment, labor-saving devices and equipment, and other devices that apply external forces alternately to a pair of left and right crank arms attached to a crankshaft and have an output section that rotates integrally with the crankshaft.

[0134] 3 Swing tension member 5 Output section A Swing arm A1 Swing arm tip block A2 Swing arm rear end block A3 Guide bar A4 Fixed swing fulcrum axis AX Fixed swing fulcrum axis center CA Crank arm CX1 Crank axis CX1a Crank axis center CX2 Crank rotation axis CX2a Crank rotation axis center F Frame N Elastic tension member Nt Tension abutment member P Pedal PH Highest point PL Lowest point PX Pedal axis center S1 First slider S1f First slider tip side abutment portion S1r First slider rear end side abutment portion S2 Second slider S2f Second slider tip side abutment portion S2r Second slider rear end side abutment portion S21 Second slider front block Z Pedal shift type crank rotation drive mechanism

Claims

1. A pair of left and right crank arms fixed to both ends of a crank shaft rotatably attached to a frame or the like, and operating with an operating phase angle difference of 180 degrees; a crank pivot shaft provided at the tip of each of the pair of left and right crank arms; a pair of left and right swing arms journaled on a fixed swing fulcrum shaft fixedly disposed on the frame or the like at a position away from the crank shaft by more than the length of the crank arm; a pair of left and right first sliders journaled rotatably on the crank pivot shaft and held by the swing arms, capable of reciprocating along the longitudinal direction of the swing arms, with the first slider tip-side abutment portion and the first slider rear-side abutment portion held in opposite directions, so that they move integrally in the longitudinal direction when the direction of the fixed swing fulcrum shaft in the longitudinal direction is the rear end side and the opposite direction is the tip side; a pair of left and right second sliders that are held by the swing arm and are reciprocatable along the longitudinal direction of the swing arm, wherein a second slider front end abutment portion and a second slider rear end abutment portion that move integrally in the longitudinal direction are held facing each other with a predetermined interval between them, and the second sliders intermittently reciprocate within a movable range in the same direction as the reciprocating movement of the first slider due to abutment or non-abutment between the opposing first slider front end abutment portion and the second slider front end abutment portion, or abutment or non-abutment between the opposing first slider rear end abutment portion and the second slider rear end abutment portion; a pair of left and right pedals attached to a second slider front block configured to be located further towards the tip end than the first slider of the swing arm during the reciprocating movement of the first slider, which alternately swings the left and right swing arms by alternating operation of the second slider front block, and which, in conjunction with the swinging, applies a rotational force to the crank arm via the first slider while tracing a deformed elliptical locus, and at the same time applies a rotational force to the crank shaft; 2. A pedal shift type crank rotation drive mechanism as described in claim 1, comprising: an elastic tension member having a tip-side abutment portion held on either the first slider or the second slider, and a tension abutment member having a tip-side abutment portion held on either the second slider or the first slider, in order to transmit a force that moves the second slider to the tip side in the longitudinal direction within its movable range while performing abutment contraction in response to the amount of reduction in the gap between the first slider and the second slider front block.

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