RU2536995C1 - Bicycle pedal crank gear - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to bicycle pedal crank gear. Proposed crank gear consists of pedals fitted on pins and connected with free ends of con-rods opposed on carriage shaft that have parts extending axially. Said parts fixed with carriage shaft have ledges arranged at surfaces opposite their pedals. Pedal pins in free ends of extending parts can revolve along with fixed pedals and terminate at opposite sides of con-rods with single-arm levers. Single-arm levers are located parallel by pedal bearing surface in direction to their heel area. Free end of single-arm levers have ledges. Said ledges are coupled via bars with ledges of con-rod parts fixed with carriage shaft.

EFFECT: better controllability.

1 tbl, 4 dwg

Description

The invention relates to transport engineering, and in particular to a device for pedal driving a bicycle to increase the conversion of the muscular effort of the extensor tibia on the bicycle pedal to the energy of its movement.

The classic pedal crank mechanism of a bicycle is widely known, consisting of pedals that have the ability to rotate in their axes, motionlessly connected to the free ends of the opposite connecting rods at an angle of 180 °. This mechanism creates the opposite movement of the legs in a circle, but, ceteris paribus, it does not allow to increase the conversion of the muscular effort of the legs on the pedals into the energy of movement of the bicycle, reduce the bending angles in the knee joints and with less effort overcome the top dead center when the pedals are at maximum high position from the carriage. These shortcomings, with long riding, as well as on rough roads and uphill, can cause overstrain of the muscles of the legs, premature fatigue and limit the use of the bicycle by people with poor health. Known connecting rod [RF Patent for the invention No. 2117599], taken as a prototype, containing a main head mounted on the leading axis of the pedal mechanism, a rod with a blind hole for placement of a spring-loaded rod completed by the pedal head, the rod and rod are sliding in the axial direction. The essential features of the prototype are that the connecting rod consists of cylindrical axially sliding parts and a compression spring; threaded connection of parts; ergonomic biomechanics taken into account; it is possible to adjust the length of the connecting rods taking into account the anthropometric characteristics of the driver. The spring-loaded rod of this device allows, by changing the pressure on the pedal, to increase the lever arm when the connecting rod is leading, and to reduce the lever arm when the connecting rod is driven, and also accelerate the connecting rod exit from top dead center.

However, this device has several disadvantages that complicate its use. Dependent on the applied forces, the pedal displacements coaxial with the connecting rod increase the degree of freedom of movement of the feet, reduce their fixation on the pedals and the necessary connection with the pedals, which reduces the bike's handling, especially with sudden changes in pedal effort. As a result, this design of the connecting rod cannot provide a combination of increasing the conversion efficiency of the muscular effort of the extensors of the shin on the bicycle pedal into the energy of its movement with high controllability of the bicycle. In addition, with this design of the connecting rod, the clearance between the pedal in the lower position and the roadbed is reduced by 22.5 mm, which also reduces the controllability of the bicycle and increases the risk of injury.

In connection with the foregoing, we have set the task of creating better conditions for increasing the conversion of the muscle effort of the tibia extensors on the bicycle pedals to the energy of its movement in combination with a decrease in the angle of flexion in the knee joints when the pedals are positioned above the carriage, and the clearance between the pedal is lower than the carriage and the roadbed and bike control.

This problem is solved by the fact that in the proposed device, consisting of pedals (1), the axes of which (2) are located at the free ends opposite to the shaft (8) of the carriage of the located connecting rods having axially sliding parts (3 and 3 *). In this case, the parts (3) fixedly connected to the carriage shaft, according to the invention, have protrusions (4) on the surfaces opposite to their pedals, and at the free ends of the connecting parts (3 *) of the connecting rods, the pedal axes can rotate with the pedals fixed to them and the ends of the connecting rods end on the opposite sides of the pedals with single-arm levers (5) located parallel to the supporting surface of the pedals in the direction of their heel region. Moreover, the free ends of the single-arm levers (5) on the surfaces opposite to their pedals have protrusions (6), which, by means of rods (7) are movably connected to the protrusions (4) of parts (3) fixedly connected to the shaft of the carriage.

The essence of the claimed device is illustrated using the drawings (see Fig.1-4). Figure 1-4 schematically shows the main 4 points in the operation of the device, explaining (with the traditional pedal rotation with the feet counterclockwise) the increase in the length of the connecting rods located in front of the carriage - when the stop pressure on the pedals is effective to increase or maintain the working stroke of the bicycle (muscle transformation the efforts of the shin extensors on the bicycle pedal into the energy of its movement), and the reduction of the length of the connecting rods located behind the carriage - when the pressure of the feet on the pedals is counter-effective to increase or maintain the work the other course of the bike, reducing the angle of bending of the leg in the knee joint when the pedal is in the upper position from the carriage, as well as increasing the distance between the position of the pedal below the carriage and the road surface.

The inventive device, which is installed on both sides of the bicycle, operates as follows (see Fig.1-4). When you press the pedal located in the upper position from the carriage (from position No. 1), to move the connecting rod forward to a horizontal position, the rod 7 is angularly (with a minus sign) moving the rod 7 to its parallel location with the longitudinal axis of the connecting rod, resulting in a second connecting rod part partially leaves the first one and the total length of the connecting rod increases as much as possible in position 2. With further pressing the pedal located in front of the carriage from position 2 to its lowest position relative to the carriage (position No. 3), etc. It extends angular (but with a plus sign) moving the rods relative to the longitudinal axis of the rod, whereby the second part of the connecting rod is in the first part and the total length of the rod is reduced. With the further movement of the pedal from the lowest position (from position No. 3) to the rear position with respect to the carriage with horizontal connecting rods (position No. 4), the rod moves angularly (with a minus sign) to its parallel position with the longitudinal axis of the connecting rod, as a result whereby the second connecting rod part continues to enter the first and the total length of the connecting rod is reduced to a maximum. With further movement of the pedal from the rear position with respect to the carriage with horizontal connecting rods (from position No. 4) to the highest position (position No. 1), the rod moves angularly (but with a plus sign) with respect to the longitudinal axis of the connecting rod, resulting in the second part of the connecting rod partially leaves the first and the total length of the connecting rod increases to a size equal to position No. 3, but remains less than its maximum length observed in position No. 2. The specified cycle of changing the length of the connecting rod is repeated with each revolution around the carriage associated with pressing the foot on the pedal.

When performing natural rotational movements with feet resting on the pedals, the latter are in an unchanged horizontal or close position at all points of their spatial orientation with respect to the carriage. In this case, the rod 7 makes 2 oscillatory movements per revolution of the connecting rods around the carriage with an amplitude equal to the distance between the protrusions (6) on the free ends of the one-arm levers and the pedal axis (2), which ensures the operation of the claimed mechanism according to a practical and independent of the attached muscle efforts fixed to a given point in space the change in the length of the connecting rods. This expediency lies in the fact that the connecting rods, being alternately located in the upper zone from the carriage, uniformly increase their length from the minimum value in the extreme position of the pedals in the back to the maximum in the extreme position of the pedals in front. And, on the contrary, alternately being in the lower zone from the carriage, the connecting rods uniformly decrease their length from the maximum value in the extreme position of the pedals in front to the minimum in the extreme position of the pedals in the back.

Table 1 shows examples of changes in the length of the connecting rods at various fixed distances between the protrusions (6) at the free ends of the single-arm levers and the pedal axis (2). From the data given in Table 1, it is seen that a decrease in the angle of flexion in the knee joints in the extreme upper position of the pedals is provided by rods of shorter length, equal, for example, to 165 mm, instead of standard rods to 170 mm. With the indicated shorter length of the connecting rods, they can increase their length to 235 mm in the position of the pedals in front of the carriage with horizontal orientation of the connecting rods (position No. 2). In this position (position No. 2), the connecting rod creates the lever arm of the longest length and, therefore, the conditions for the most (up to 38%) effective conversion of the muscular effort of the tibia extensors on the bicycle pedal into the energy of its movement in comparison with those conditions that provide classic connecting rods of 170 mm models and prototype.

In addition, when the pedals are in the back of the carriage, when the weight of the legs and the pressure of the feet on the pedals are counter-effective for converting muscle effort into the energy of movement of the bicycle, the connecting rods reduce their length to 95 mm. As a result, the claimed device creates better than the prototype conditions for increasing the conversion of muscle effort into energy of the bicycle’s movement, since the unequal length of the arm levers located in front and behind the carriage, in favor of exceeding the length of the arm arm located in front, allows you to save muscle effort useful and negative work, to overcome the upper and lower dead points, which occurs automatically due to an increase in the inertia of the movement of different levers, led to controllability ciped by maintaining the degree of freedom of movement of the feet, regardless of the applied muscle effort on the pedal. Shortened to 165 mm the length of the connecting rod in the inventive device reduces the angle of bending in the knee joints when the pedals are located above the carriage and increases the clearance between the roadbed and the pedal in its lower position from the carriage. The increase in clearance between the roadbed and the pedal in its lower position from the carriage is 5 mm relative to the 170 mm connecting rod of classic bicycle models and by 27.5 mm in relation to the prototype.

Thus, the problem of the invention has been solved to create better conditions for increasing the conversion of the muscular effort of the tibia extensors on the bicycle pedal to the energy of its movement in combination with a decrease in the bending angle in the knee joints when the pedals are positioned above the carriage, an increase in the clearance between the pedal is in the lower position from the carriage and the road surface and maintaining the controllability of the bike.

Comparative analysis with the prototype shows that the inventive device, consisting of sliding parts of the connecting rods, is characterized in that some parts are motionlessly connected to the carriage shaft and have a protrusion on their surface, and at the free ends of other parts, the pedal axes are able to rotate with the motionless to connected pedals and end on the opposite sides of the pedals of the connecting rods with one-arm levers located parallel to the supporting surface of the pedals in the direction of their heel region, and the free ends of the one-arm levers have protrusions, which, by means of rods, are movably connected to the protrusions of the parts of the connecting rods fixedly connected to the carriage shaft.

Thus, the claimed device meets the criteria of the invention of "novelty" and "significant differences".

LITERATURE

1. RF patent for the invention No. 2117599

Table 1 Automatically changing lengths of the connecting rods in the cycle of their rotation around the carriage counterclockwise at different distances between the protrusions on the surface of the single-arm levers and pedal axes The distance between the protrusions and pedal axes, mm Pedal position when rotating around the carriage, No. Rod Length mm average per cycle actual mm % increase in relation to the average 12 one 165 165 12 2 177 7.3 12 3 165 12 four 153 thirty one 165 165 thirty 2 195 eighteen thirty 3 165 thirty four 135 40 one 165 165 40 2 205 24 40 3 165 40 four 125 fifty one 165 165 fifty 2 215 thirty fifty 3 165 fifty four 115 60 one 165 165 60 2 225 36 60 3 165 60 four 105 70 one 165 165 70 2 235 42 70 3 165 70 four 95 Note: the position of the pedals No. 1-4 in the cycle of rotation with their feet around the carriage counterclockwise is presented in the text and in figures 1-4.

Claims (1)

The pedal crank mechanism of a bicycle, consisting of pedals, on their own axis connected to the free ends of the rods opposite on the shaft of the carriage, having axially sliding parts, characterized in that the connecting rod parts that are motionlessly connected to the carriage shaft have surfaces on the opposite to their pedals along protrusion, and the pedal axes in the free ends of the sliding parts have the ability to rotate with the pedals attached to them motionlessly and end on opposite m pedals sides connecting rods single-armed levers disposed parallel to the support surface of the pedal towards its heel region, wherein the free ends of the one-armed levers each have a ledge which, through rods movably connected parts with projections of rods fixedly connected with the carriage shaft.

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