Dear cyclists and cycling enthusiasts!

Do not rush to throw away bicycles produced during the USSR.

We present to your attention a project of a removable lever drive, with which you can easily give new life to your old and proven iron friends.

By implementing this project in practice, you can not only prove to yourself and those around you that you are worth something in life, that you are capable and can make anything with your own hands, but you will also receive a copy of an original, unique in the world, bicycle of an extraordinary design that will be the subject of envy Your neighbors and friends.

Advantages of using the system compared to classic bicycles: - no dead spots, the force is transmitted continuously and evenly, and the power remains constantly high. In practice, this means that the cyclist will use less energy to achieve the same speed.

Below is a graph comparing the distribution of torque for a classic bicycle and the proposed sample.

Where: A is the distribution of the moment of force of a classical bicycle during one working cycle.

B – distribution of the moment of forces of the proposed bicycle for one working cycle.

M is the moment of force equal to the product of the applied force and the length of the lever.

N is the value of the wheel's travel distance per one working cycle.

It is clear from the graph that lengthening the lever leads to an increase in the moment of force several times, although the stroke length of the wheel decreases somewhat, which forces the cyclist to work more intensely with his legs, but this, in the author’s opinion, is not a negative effect, but on the contrary .

And due to the fact that the vector of the applied force is always directed downwards, we can make the most efficient use of our body weight for an easy start and quick acceleration.

Increasing the power (speed) of the drive by lengthening the levers with a constant force applied by the cyclist

Unlimited amplitude of pedal stroke within specified limits

Movement is achieved by applying a force tangentially to the surface of rotation

In addition, the danger of rolling backwards when driving on mountain roads is eliminated, due to the absence of reverse gear.

Such results were achieved through the use of an innovative mechanism that converts the reciprocating and oscillatory movement of levers with pedals into a one-way rotational movement of the wheel using simple auxiliary devices.

The author has also developed the “know-how” of changing torque during movement without the complex, cumbersome, expensive gear shift system used on most modern bicycle designs.

For the practical implementation of the proposed project, you will need parts from classic bicycles, such as modern models, and previously produced on the territory of the USSR. Namely : frame, handlebars, seat, front and rear wheels, some parts of the hub (carriage) rear wheel, small bicycle sprockets, segments bicycle chain, carriage with pedals, hand brake.

Additionally manufactured : levers with bearing races and pedals, fastening bracket, U-shaped tube, linings, earrings. To manufacture bearing races and mechanism parts, you will need the services of a lathe and milling machine, and to weld individual parts, you will need a welder with a welding machine.

For making Y - of shaped levers, a section is best suited ½” water pipe flattened on both sides to give it an oval shape (see photo).

We recommend making small levers from the levers of the carriage pedals from a regular bicycle. In this case, the pedal axles are used, which must be shortened to required length and cut the M8 thread. Then a piece of flattened water pipe and levers are welded to the bearing races.

Levers with carriage pedals from a regular bicycle are also used in the design Y - shaped levers. For this purpose, the levers are cut to the required length and ground on an emery wheel to a size at which they can be freely inserted into the free end of a flattened section of water pipe.

As can be seen from the figure, Y-shaped levers, with sections of a bicycle chain attached to them, performing reciprocating movements, rotate the sprockets in contact with the chains, which are articulated with a mechanism that converts reciprocating motion into rotational motion, mounted in the rear wheel hub (not shown), causing the wheel to rotate.

When the farthest (in the figure) lever moves from top to bottom, a working stroke is performed. At the same time, the near lever moves upward. Next, the near lever, having reached the top point, begins to move down, in turn, making a working stroke and completing the cycle. And so on.

The purpose of creating the above sample bicycle there was an increase (2-3 times) in the force transmitted by the cyclist to the drive wheel due to lengthening of the levers and the use of the proposed mechanism without the use of ratchet mechanisms.

Photo of the invented mechanism assembled and mounted in the rear wheel hub holder.

Below is a photograph of another version of the bicycle manufactured and successfully tested by the author, as well as a photograph of the very first version

on which a positive result and unforgettable impressions and sensations from riding it were obtained for the first time.

When driving on a flat road, even a country road, it felt as if driving did not require any leg effort at all. The legs simply moved up and down, as if walking in place, completely freely.

Then the idea arose to improve the drive by simplifying the design. This is how the sample shown and described at the beginning of the article appeared.

However, for those wishing to repeat the “Second Option” design, some details are recommended.

In particular:

It is not necessary to weld the additional tube to the frame indicated in the photo and sketch. Enough to use

existing vertical stand;

As additional sprockets, sprockets from a children's tricycle were used. For this,

the sprockets must be riveted, the ratchets removed and riveted again. In this case, the stars should rotate

completely free;

Drill an 8 mm hole in the vertical post. Insert an M 8 bolt into the hole, onto the bolt with inside

put on a 3 mm thick washer, an asterisk, a washer and fasten everything with an M 8 nut.

If you are interested in all of the above and would like to know more details, please contact me by email: [email protected] or call: +375 33 639 24 62

GOOD TRAIL TO YOU! CLEAR AND SLIGHT ROAD !

Hi all! Today I will have a very interesting and informative article for you about which pedals to choose for a bicycle. You will also find out what types of bicycle pedals exist, and I’ll tell you a little about their design and maintenance.

1. Bicycle pedal structure

Well, first we’ll start with a little theory. What exactly are bicycle pedals?

Bicycle pedals- an integral part of the system (rods), which sets the bicycle in motion using the force of the cyclist’s legs, followed by rotation of the carriage shaft and then through the transmission to the rear wheel.

Let's look at their design using the example of the classic and most common bicycle road pedals. So, they consist of:

Both ends of the axle are threaded. To screw into the connecting rod, a thread M14x1.0 or M14x1.25 is cut. They are screwed on the left - with a left-hand thread (unscrewed clockwise), and on the right - with a regular right-hand thread (unscrewed counterclockwise). This method of fastening prevents the pedals from being twisted tightly when rotating, and it is believed that in this way they do not get twisted while driving. At the opposite end of the axle there is a standard M7x1 thread (right), onto which a cone is screwed. This cone makes precise adjustment of the ball bearings. An additional groove is cut along this thread, in which the shoulder of the washer is fixed, installed between the locknut and the end of the cone. The axle ball path, cone and pedal cups are hardened to create a hard surface, and all surfaces on the outside of the parts are chrome plated.

At first glance, bicycle pedals seem to be a fairly simple mechanism, but the variety of their types and manufacturers can confuse an unprepared person who decides to purchase them for his two-wheeled friend.

2. Choosing bicycle pedals

According to their design, bicycle pedals are divided into 3 large categories:

• Platform- can be used with almost any shoe;
• Contact- used in conjunction with special cycling shoes;
• Combined- on one side they have a regular platform, and on the other - a contact mechanism and allow you to wear any type of shoe.

Based on their purpose, pedals are divided into several types:

• Walking- designed for city driving and made of a plastic body. Quite weak and too slippery for off-road riding.
• General purpose- mainly include combination and metal platform pedals.
• Cross Country- these are lightweight, platform-free contact pedals, require special shoes.
• Extreme disciplines- pedals with powerful cleats located on the platform, also contact pedals with an auxiliary platform.
• Highway- these are contact pedals that are not compatible with mountain pedals due to the fact that they have a different standard and are designed for the most rigid fixation of the feet.

3. Types of pedals

Let's now take a closer look at all the existing types of pedals so that you can better navigate when choosing them in the store. Let's start from the simplest cheap ones and end with the professional and expensive ones. This way you will understand what style of riding these or those pedals are suitable for.

3.1 Platform pedals

They are the simplest and are usually installed on cheap bicycles. The body is made primarily of plastic. Such pedals are used for recreational and city bicycles. They have a rather flimsy design, and accordingly, they do not hold the legs well, which is why they will constantly slip. The starting cost of walking pedals is about $5, and they are made by companies such as Longus, VP and other lesser-known ones.

They differ from the previous ones in their metal body, mainly made of aluminum, and have spikes on the surface of the platform. They are used both for city walks and for cross-country, you can also say that these are pedals entry level, for those who have not yet decided on their riding style. Installed on mid-priced bicycles. Manufacturers: VP, Longus, Wellgo, etc. Price from $7.

MTB pedals, or “treadmills” in cyclist slang, are predominantly made of aluminum alloys. Unlike recreational ones, they are of higher quality and are already at a higher level. MTB pedals have a wider platform and are most often used for non-aggressive riding. They can be with spikes, which significantly improves the grip of the foot on the surface, or without them. Used not only by cross-country enthusiasts, but also by BMXers. You can find cross-country pedals in a bike store starting at $10 under the following brands: VP, Wellgo, Xpedo, etc.

In their design, such pedals, in addition to the platform, also have special straps that provide the cyclist with a tight fit of the legs while riding. The foot is placed on the platform and is additionally secured with a strap. By design, they are similar to contacts, but they are significantly inferior to them, and at the same time they are much better than regular ones. Pedals with toe clips (from English. toe clips) seem to be a kind of “golden mean”, but are still significantly outdated and are used mainly by cyclists of the “old school” or on touring and track bicycles.

Here, in comparison with walking pedals, the fixation is much better, and, as with the contacts, the problem of “dead spots” is solved. If you still opt for toe clips, then you will need to practice well beforehand in order to learn how to quickly pull your leg out. To prevent disruption of blood circulation in lower limbs, you should not over-tighten the straps, but at the same time, they should be tightened tightly.

A rather unusual design of walking platform pedals with a simple but quite reliable rotary-folding mechanism, which allows you to significantly reduce the dimensions of the bicycle. They are best suited for folding compact bikes. The axle is made of high-strength alloy, which maintains strength and rigidity while driving. The main idea of ​​folding pedals is ease of storage and transportation; they also will not allow you to cling to your bike if it is at home. Such pedals are extremely rare, and their price is about $12. They are made mainly by Author and VP.

If you are a fan of downhill and extreme skating, then you should pay attention to professional pedals with a platform and contacts (half-contact pedal). This is something between MTB and contact pedals and they are considered combined, because... applied in two disciplines. Their peculiarity is that on one side there is a regular platform, like on pedals general purpose, and on the other - a special contact mechanism for fastening cycling shoes.

Aluminum alloys are used to produce semi-contact pedals, and for the cross-country discipline it can even be carbon. They look impressive - many aggressive elements, a wide platform on which it is very comfortable to place your foot, and the presence of spikes and contacts prevent it from slipping. You can find such pedals under the brands VP, FDP, Shimano, etc. at prices starting from $30.

The advantages include the fact that you don’t have to buckle up in particularly difficult riding conditions and ride on a platform. There is also no connection to any one type of shoe. You can also buy pedals first and then shoes.

Among the disadvantages, the following can be highlighted: inconvenience when starting to move, and with any shoes, because first you need to find the required side of the pedal with your feet; The clip-in speed drops significantly, especially for experienced riders who are used to riding on contacts, because they need trampling much less often than it might seem from the outside; It is not necessary to buy combination pedals; it is enough to use a special adapter platform for contact pedals.

This variation of bicycle pedals is perhaps the most popular in the cycling community. They do not have platforms, like the models described above, but they have a special mechanism for fastening. As a rule, they come with special spikes, which are used for fastening and unfastening.

SPD cleat attachment
Attaching the contact pedals

The main material for the manufacture of contact pedals is various aluminum alloys. To use them you will need special cycling shoes. Manufacturers include Shimano, VP, Mavic and others. Starting price is approximately $35. You can read more about contact pedals in the next article.

Applicable only to road bikes and have a very rigid mount. Due to the fact that dirt rarely gets on such pedals, their design is made in such a way as to fix the foot as clearly and firmly as possible. In addition, they provide maximum stability due to the large contact area between the shoe and the pedal. But the frame that secures the spike can be about a third of the length of the shoe. Road pedals are almost always single-sided, due to their size, so as not to excessively increase the weight of the entire structure.

SPD-SL cleat mounting
Attaching Road Pedals

Well, of course, just like for contact pedals, you will need special shoes and cleats, which are fastened with three bolts (usually included in the kit). The spike is composite or plastic and spans the width of the entire sole. Contact shoes for road pedals with very hard soles do not have tread, which makes it almost impossible to walk in them. The most popular among cycling enthusiasts and professionals are Shimano, Look, Wellgo, etc. Some road bike owners still prefer “mountain” pedals for their versatility. The price is quite varied, ranging from $40-60 and above.

4. Pedal maintenance

Regardless of what pedals are installed on your bicycle, inexpensive or with reliable protection, it is recommended to check the condition of the bearings and change their grease once a season. For pedals with poor moisture and dust protection, the lubricant must be changed as soon as a characteristic crunch appears in the bearing.

When servicing the pedals, you first need to remove any remaining old grease and dirt using a rag or paper towel. You need to clean the cups inside the body, the axle and the balls. If it is an industrial bearing, then you must first remove the boot from it and then remove the old grease. Once the old lubricant has been removed, new grease can be applied. To do this, you can use lithol or a special lubricant, which is sold in every bike shop.

In order to protect the holes for the studs (if you remove them) from dirt, you can fill them with wax. Periodically it is also recommended to check whether the nuts on the axle are loose, but you should not tighten them too tightly either. It is best to have replacement shoes for cycling to reduce the likelihood of dirty pedals.

Well, I hope this article was useful to you and now you know how to choose pedals for your bicycle. In the next article we will take a closer look at contact pedals, their advantages and disadvantages, and also dispel the most common myths. And finally, I recommend that you watch the video in which you can visually familiarize yourself with the pedals described above. That's all for me, see you soon on the blog!

Let's consider how the movement of a bicycle occurs during inertial motion. While free rotation continues rear hub, you can choose a position for the pedals that is convenient for you, so that you can start working with them again when the inertia stroke ends. The most effective position in this case is the highest position of the pedal, since by applying force precisely to this point, you can perform the most useful work.

Of course, this position is due to the fact that the cyclist himself is above the pedal hub. If you had to rotate the pedals, say, lying on your back, and the large gear was located at the top, the most convenient point of the working pedal would be the lowest one.

At the moment when the foot is at the highest point with the pedals strictly vertical, it is useless to press on them. In this way, the gear still cannot be moved. This state of the shaft exists in all modern machines; it is called the “dead point” - the moment when a rotating force is applied to the center of the shaft.

An experienced cyclist knows that at this moment the pedal needs to be pushed a little forward, and then down. And you can hear from cyclists that the whole trick to riding a bike quickly is that you don’t need to “press” on the pedals, but rather “rotate” them.

Why is there no such thing as a “dead spot” in bicycles that do not have a ratchet?

The rear wheel plays the role of a flywheel, and the chain drive prevents the pedals from stopping at any point. Once the pedal arms are in a vertical position, the inertia of the rear wheel flywheel will cause them to turn further.

And yet you can get rid of the “dead point”. And at the same time increase the travel of the front gear.

In 1963 in France there was the bicycle was invented with pedals-rods. You can see its design in the photo above. As you can see, additional knees are suspended from the pedal arms. With such pedals, a cyclist can do much more work and get significantly less tired.

You can improve your bike in a similar way by changing the design of the frame and pedal arms.

It is better to experiment with an old bicycle with a classic frame configuration, in which the rear fork allows you to adjust the position of the rear hub.

First of all, it is necessary to change the frame configuration (see figure). To do this, saw off the lower front pillar and file the cuts. After this, cut out the pedal bushing along with the rear fork. Weld the freed tube from the front strut to the pedal bushing axial to the rear fork. Then stretch the twine on the frame from the cut point of the front post to the cut point on the rear fork and mark where the string intersects the center post of the saddle. From the marking point, measure another 3 cm (towards the saddle) and shorten the central post at this point. Attach the pedal bushing to the cut point of the center post, determine the required length of the front post and trim off the excess. Then weld the pedal hub along with the rear fork to the bike frame.

Along the length of the sawn section, make two additional elbows for the pedal levers from a steel strip 4...5 mm thick and 20 mm wide (see figure). Drill two holes in them. After this, unscrew the pedals and screw in the additional elbows. And in turn, screw the pedals to them.

Once you try out the new pedal design, you will find that the sticking point seems to disappear. This happens due to the additional angle between the pedal and the lever. At the same time, a new power reserve has appeared, as a result of which the cyclist accelerates faster from a standstill and gets less tired when going uphill.

"Lefty" No. 8 2005

Use of the invention in bicycles. The essence of the invention is that a device that changes the length of the bicycle pedal levers allows you to simultaneously change the length of the levers of both pedals to both increase and decrease torque. A device that changes the length of the levers in order to change the torque, having a guide sleeve and a movable lever, with movable stops, a shaft having a protective coupling with protrusions and a gear that engages with grooves on the movable lever. 6 ill.

The invention relates to vehicles powered by human muscle power. On sports bike To change the torque, several pairs of sprockets and a device for transferring the chain to these sprockets are used. French Patent N 610396, 1930. A bicycle lever having a movable element, a movable pin and a spring, a guide sleeve having holes for installing this pin; when the location of the pin changes, the length of the lever changes, resulting in a change in torque. A device is known that changes the length of the levers to change the torque, containing a guide sleeve, a movable lever with grooves, movable stops, a shaft with a gear for engagement with the grooves of the movable lever, installed in the guide sleeve and its retainer /FR, N 535191, 1922/. The mobility of the lever in the prototype is limited, and it is also difficult to install the required length. The device is designed to simultaneously change the length of both bicycle pedal levers and provides more convenient control of them, unlike the prototype. Depending on the extended pair of stops, it is possible to either increase or decrease the torque, i.e. lengthen or shorten levers. In fig. 1 shows the right pedal of a bicycle (the left one has a similar device); in fig. 2 shaft with protective coupling and gear; in fig. 3 view A shown in figure 1; in fig. 4 system of levers for extending the stops; in fig. 5 view B of figure 4; in fig. 6 top view FIG. 4. In FIG. Figure 1 shows the right pedal of a bicycle with an asterisk, movable stops 2 and 3, a shaft 4 with a protective coupling 5 with protrusions and a gear 6, a retainer 7, a guide sleeve 8, a movable lever 9 with grooves 10. The left pedal has a similar device. Stops 2,3,11,12 are located in guide posts 13,14; lever 15 is installed on axis 16, there is also a cable 17 with a spring 18. Lever 19 is connected to stops 3 and 12. The shaft with a protective coupling 5 and gear 6 has a movable plate 20 with grooves, a bolt 21, a washer 22, a fixed plate with protrusions 23 and a spring washer 24. When extending the stop 2, it will engage with the protrusion of the protective coupling 5. When the pedals rotate, shaft 4 will rotate to the next protrusion and be locked with lock 7. With each revolution of the pedal, shaft 4 will rotate to the next protrusion of the clutch 5. Gear 6 through grooves 10 will be moved by lever 9. When the stop 3 is extended, shaft 4 will rotate in the opposite direction, lever 9 will correspondingly move in the opposite direction. Clutch 5 is designed to protect shaft 4, gear 6 and grooves 10 in the extreme positions of lever 9. When tensioning cable 17, lever 15 will extend stops 2 and 11. Spring 18 returns the stops to starting position. Lever 19 extends stops 3 and 12.

Formula of invention

A device that changes the length of the levers to change the torque, containing a guide sleeve, a movable lever with grooves, movable stops, a shaft with a gear for engagement with the grooves of the movable lever, installed in the guide sleeve, and its retainer, characterized in that a protective coupling is installed on the shaft with protrusions for engagement with movable stops and a mechanism for controlling the movable stops for changing the length of the levers.

Similar patents:

The invention relates to a pedal crank mechanism for a bicycle. The pedal crank mechanism of a bicycle consists of pedals connected on their own axis to the free ends of the carriage shaft, which are oppositely located on the shaft of the carriage, with connecting rods having parts sliding in the axial direction. The connecting rod parts, fixedly connected to the carriage shaft, have protrusions on the surfaces opposite to their pedals, and pedal axles at the free ends of the sliding parts they have the ability to rotate together with the pedals fixedly attached to them and end on the sides of the connecting rods opposite to their pedals with single-arm levers located parallel to the supporting surface of the pedals towards their heel area. The free ends of the single-arm levers have protrusions, which, by means of rods, are movably connected to the protrusions of the connecting rod parts, fixedly connected to the carriage shaft. Improved bike handling is achieved. 1 table, 4 ill.

A device that changes the length of levers to change torque, bicycle torque, how to change torque

The bicycle is perhaps the most common vehicle. And there is no doubt that it is the most economical: two sandwiches with butter are enough to pedal for two hours. But is it possible to increase the efficiency of the human “engine”? Reducing fuel costs won't do anything. Friction and weight of the machine are reduced to almost a minimum. There is also a "gearbox" device for changing gear ratio by throwing the chain onto small or large sprockets. All that remains is to lengthen the pedal arms, but experts categorically state that their optimal length is 170 mm.

The original solution was the ellipsoidal drive sprocket proposed in recent years. Readers are familiarized with this invention in detail. With the help of an ellipse, the gear ratio changes cyclically, better adapting the pedal mechanism to the person, but... without making the work easier.

In the device brought to the attention of readers (Fig. 1), it is possible to synthesize the advantages of an elliptical sprocket and “long” levers: here the torque increases when, under pressure, the unusual levers seem to lengthen, at the same time describing an ellipse curve, although the drive sprocket retains the correct circle . This achieves a gain in strength and eliminates uneven changes in the gear ratio; the legs describe a circle with an optimal radius of 170 mm.

1 - bicycle frame, 2 - front wheel, 3 driving sprocket, 4 - pedal additional lever, 5 - lever sprocket, 6 - additional chain drives, 7 - connecting rod, 8 - bracket.

DEVICE

The pedal mechanism (Fig. 2) here too is not without the usual main lever - connecting rod 4, on the hub of which an auxiliary sprocket 9 is placed. It is mounted motionless relative to the bicycle frame - through bracket 11. An auxiliary extension lever 12 is attached to the free end of the connecting rod on a hinge pedal 13. The second auxiliary sprocket 14 is fixedly fixed on the lever shaft 12. Both gears have the same number of teeth and are connected to each other by a chain.

OPERATING PRINCIPLE

1 - drive sprocket mounting plate, 2 - bracket, 3 - key, 4 - main lever (connecting rod), 5 - pin, 6 - bushing, 7 - roller, 8 - bearing bushing, 9, 14 - auxiliary sprockets, 10 - support , 11 -*

brackets. 12 - extension lever, 13 - pedal. 15 - bearing ball, 16 - bolt, 17 - auxiliary sprocket bushing, 18 - washer. 19 - axis of the extension lever.

When you press the pedal 13, the main lever begins to rotate, while the sprocket 9 (through the chain and the second auxiliary sprocket 14) keeps the extension lever 12 always directed forward and horizontally. In this case, the general trajectory of movement of the extension lever is an ellipse, in the “front” half of which the largest radius falls on the pedal, and in the rear half - on the lever hinge. Thanks to this, the forward pedal allows you to press it with maximum force precisely on the most effective part of the path - from the top dead center to the bottom, that is, when the main lever seems to lengthen, which ensures a gain in strength. Although in fact, when pedaling, they describe a regular circle with a radius equal to length connecting rod (optimal length - 170 mm), but extended forward by the length of the auxiliary lever (Fig. 3).

MANUFACTURING

For simplicity, we will consider the parts one by one in order, as they are indicated in Figure 2. Plank 1 is made of pickled steel with a thickness of 5 mm. The connecting rod drive sprocket is bolted to it. Depending on its diameter and the shape of the middle part, the dimensions of the load-bearing part of the plank are selected (not shown in the drawing). Bracket 2. Two such brackets are made of pickled steel 3 mm thick. With them, the supporting bar is fixedly attached to the hub of the right main lever - with M6 X 8 screws with a countersunk head. Key 3. You will need two, made of St45 steel; their dimensions are determined by the cutout in the axis of the connecting rods and the size of the hub keyway. Main lever 4. There are two of them - right and left, made of St40X steel. They are connected to their arms (4) by welding. The groove for the key in the bushings must be on the same side relative to the lever. The hole for the pin (5) in the latter is drilled after welding through the sleeve. Hairpin 5 is made of spring steel 65G without additional heat treatment. Bushing 6. There are two of them - right (for the right lever) and left (for the left). Material - StZ steel. Roller 7. Rollers d 2.4X 10.5 mm from the old crosspiece of the VAZ-2101 car were used.

Bearing sleeve 8. You will need two made of St40X steel. Four holes d 5 mm are drilled into them simultaneously with the holes on the auxiliary sprocket 9 and bracket 11. Auxiliary sprockets 9 and 14.

There are four of them in total. They are standard, from the rear wheel, and have 19 teeth (sold in bicycle parts stores). On two sprockets (9), the holes are bored to d 39 mm. They can also be manufactured as one part together with the bearing bushing 8 and the supporting bushing 17. In this case, the number of teeth should not be less than 13. The main (without teeth) diameter of such a sprocket is 52.5 mm, and the outer diameter is 60.5 mm.

Support 10. Attached with two M3 screws to the left bracket 11 to provide sufficient front play between the bearing sleeve and the hub of the left main arm.

Bracket 11. With their help, the auxiliary sprockets are mounted motionless relative to the bicycle frame. They consist of three parts: a shoulder and two brackets, curved in accordance with the diameter of the frame. The material of both brackets and four brackets is 3 mm thick pickled steel. The brackets are fastened with M5 screws, and after their bend along the frame is specified, they are welded.

Extension lever 12. There are two of them: both are made of St40X steel. At one end of each there is a hole for a pedal with an M14 thread, which should be of the same name: on the right - right, on the left - left. At the other end there is a hole for the axle (19); it is welded. For greater strength, one or two blind holes d 4.9X9 mm can be made along the dividing line of the axle and lever: before welding, stumps of a steel rod d 5 mm are driven into them, acting as keys.

Ball 15. In total, 84 pieces d 3 or d 3.2 mm are required for the bearings of the extension arms.

Bolt 16. There are two of them, size M6X X 10 mm - for fixing the sprocket on the lever.

Bushing 17 for the auxiliary sprocket - two pieces - made of St40X steel. Three grooves along the periphery are machined for the protruding parts of the sprocket 14.

Washer 18. Two, made of pickled steel, 2 mm thick; internal and external diameters are 6.5 mm and 38 mm, respectively.

To manufacture the device according to data. These drawings require a hollow carriage axle. You can also use an axle with square-tapered edges, but in this case the holes in the connecting rod hub must correspond to its dimensions, and the gap between the bicycle carriage hub and the connecting rod hubs must be at least 1 mm.

The play required for normal rotation of the extension lever relative to the connecting rod is achieved by selecting the thickness of the steel washer (washers) fixed between the axis of the extension lever 12 and the washer 18.

A - main lever, B - extension lever.

The center distance between the main and auxiliary arms is approximately 172 mm. To ensure that the chain does not have weak tension, its size is determined during installation. How does this happen? Using an extension, the lever and sprocket are installed on the free end of the connecting rod. Another auxiliary sprocket and bearing bushing 8 are mounted (not completely) on the carriage axis (not completely) on the hub. A 590 mm long chain is put on both sprockets, tensioned, after which the lever and hub are welded to each other. During dismantling, the pin 5 is removed, a screw is screwed into the hole MB, and the main lever (connecting rod) is knocked out through the hole in the central axis with a suitable bit.

A trial installation is carried out, before which parts 1, 2, 4, 8, 11, 12 and 17 are subjected to heat treatment (cementing). Plastic seals made from a 1 mm thick ring of suitable diameter are inserted between the connecting rod and the extension lever, as well as between the main lever and the supporting sleeve.

The pedal mechanism with automatic extension of the levers is recognized as an invention and is protected by an copyright certificate in Bulgaria. Everyone who has tried the new product notes not only the constructive originality of the solution to the problem, but also the positive effect achieved thanks to it: the “acceleration response” of a bicycle machine equipped with such a mechanism, easier passage of difficult routes and overcoming inclines.

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