RU2294859C1 - Drive for bicycles and velomobiles - Google Patents

Abstract

FIELD: drives with reciprocating foot levers and with energy accumulation and release units.

SUBSTANCE: proposed drive includes drive shaft with cranks (1) and pedals, driven shaft with overrunning clutch in drive wheel and ropes (4). Secured to right-hand crank (1) is double-arm lever (2) which may be also mounted on drive shaft; ends of this lever have curvilinear surfaces through which ropes (4) are thrown which are secured on ends of double-arm lever (2). Center parts of ropes (4) are wound on two pulleys on which they are secured; pulleys are mounted on drive wheel for engagement with it through overrunning clutches. Fitted in center portion of double-arm lever (2) is lever (7) provided with elastic drive, spring (8) for example; second end of spring (8) is caught by frame. Proposed drive ensures accumulation of energy of foot push at the end of turn of crank.

EFFECT: enhanced efficiency.

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Description

The device is designed to convert muscle energy into rotational.

The invention relates to cars, mechanisms, vehicles and other devices using muscular traction (bicycles, velomobiles, rickshaws, etc.).

Numerous drive options are known to increase the efficiency of an existing bicycle drive, consisting of pedals, cranks, drive and driven sprockets, and a flexible (chain) transmission.

To reduce muscular effort when driving on roads with variable load (alternating ascents, descents, uneven roadbed, etc.), drives are currently being used that are equipped with a large number of sprockets of various diameters. By throwing the chain from one sprocket to another, the gear ratio of the drive changes

Such programs, despite their distribution and long history, are unreliable, expensive and difficult to manufacture products.

The rack drives proposed by some inventors, although they give an increase in efficiency, are also complicated and expensive to manufacture.

A device is known (patent RU No. 2053154, filing date 07/20/93), taken as the closest analogue, which uses a different approach to increase efficiency. In this drive, the pedals must be rotated in the opposite direction. The effect of increasing efficiency here is achieved by optimizing the kinematics of the movements of the legs of a person, with the addition of the efforts of the hands when pushing them away from the steering wheel. It should be noted that in this case only part of the trajectory of rotation is used. In particular, at the time of straightening the legs in the knee, i.e. when the force exerted on the pedal is maximum, the pedal moves along the lower part of the trajectory, and this force is almost not used when turning through an angle of 60-90 °.

The same problems with the existing bike drive. Effective footwork only occurs on part of the pedal turn. Those. both legs work effectively at best only at 180-210 ° of rotation of the drive sprocket.

Another drawback of existing designs is the low-tech basic parts: sprockets and chains. Despite the fact that their production has long been mastered, their replacement with simpler and cheaper parts seems quite reasonable.

The objectives of this invention are:

increasing the efficiency of the drive by reducing unproductive energy costs and a more rational use of muscular efforts of a person;

improving manufacturability and reducing the cost of production of drive parts.

The tasks are solved by applying a lever drive with a reciprocating motion of the cranks, a cable transmission and an overrunning clutch with a pulley. The clutch and pulley are mounted on the drive wheel, next to the second pulley mounted in place of the removed sprocket.

Common features of the proposed drive with the closest analogue selected are a drive shaft with cranks and pedals, a driven shaft with an overrunning clutch and a flexible gear.

Distinctive features are: a two-arm lever mounted on the shaft with curved profiled ends through which the ends of the cables are thrown, the middle parts of which are wound and fixed on pulleys, one of which is installed instead of the sprocket, and the second is connected to the drive wheel through an additional overrunning clutch, and in the middle part of the two shoulders of the lever there is a lever with an elastic rod, the second end of which is hooked on the frame.

Figure 1 schematically shows the drive in one extreme position.

Figure 2 schematically shows the drive in another extreme position.

Figure 3 shows a section aa (on an enlarged scale) along the end of the axis of the drive wheel with pulleys.

Figure 4 shows a variant with the connected ends of the driven branches of the cables and transferring them through a common unit.

Two pedal cranks 1 with pedals (there may be no pedals on the bike), a two-arm lever 2, to the profiled ends 3 of which are attached ropes 4, the middle parts of the ropes fixed to the pulleys 5 and 6 and laid in grooves of at least one turn. In the middle part of the lever 2 there is a lever 7, for which a spring 8 is hooked, the second end of which is fixed to the frame.

A flexible transmission may not consist of two cables, but have one, if you install a block on the frame through which to transfer the middle (driven) part of the cable.

Increasing the efficiency of the proposed drive contributes to a number of design features.

The two shoulders lever is mounted with an offset in the angle relative to the cranks. The angle α of the mutual placement of the lever 2 relative to the cranks 1 is selected so that in one of the extreme positions the angle β between the leading branch of the cable 4 and the lever 2 approaches 180 °. So that the resultant force in these positions is directed approximately along the arrow "C", i.e. almost at right angles to the leading branch of the cable. This provides better throttle response or overcoming steep climbs or other difficult terrain.

Structurally, the maximum angle of rotation of the lever 2 is selected approximately 120 °, but the angle that is rationally used in the work will be in the range of 90-100 °.

In the process of operation, the swinging movement of the pedals is carried out, and on difficult sections of the road or on climbs, only a partial turning angle can be used, which happens by itself.

The ends of the two shoulders of the lever attached to the ends of the cables, the middle parts of which are wound and mounted on the drive pulleys.

One of the pulleys is installed instead (in place) of the driven sprocket, and the other is connected to the drive wheel through an additional overrunning clutch. It should be noted that in the hub of the drive wheel the brake is removed (for those where it is available).

Curved surfaces are made at the ends of the two-shouldered lever, eliminating the unacceptable sagging of the cables. The surface through which the leading end of the cable is thrown is made along an arc of a circle. Dimensions are determined geometrically. The driven end of the cable is thrown over a round surface, i.e. a part such as a regular washer, the diameter of which is also determined geometrically, so that when the lever is turned, to ensure minimal sagging of the cable.

In the middle part of the two shoulders of the lever there is an auxiliary lever, to which is attached an elastic rod (spring, harness, etc.), secured by the second end to the frame. At the end of the rotation of the levers and cranks, the spring 8 will be tensioned, performing the role of two stops. But its main purpose is the accumulation of energy, which will be used for accelerated lifting of the legs.

The drive is manufactured and tested by operation.

Claims (1)

A drive for bicycles and cycle vehicles, comprising a drive shaft with cranks and pedals, a driven shaft with an overrunning clutch in the drive wheel, and a flexible transmission, characterized in that a two-arm lever is mounted to the right crank or the ends of the shaft have curved surfaces through which are thrown cables fixed at the ends of the two shoulders of the lever, and the middle parts of the cables are wound and fixed on two pulleys mounted on the drive wheel with the possibility of interaction with him through overrunning clutches, and the middle part of a double-arm lever has a lever with elastic traction, such as a spring, the other end of which is engaged by the frame.

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