Abstract: Rocker mechanism. Practical use. Crank-yoke mechanism For what purpose is the crank-yoke mechanism used?
![Abstract: Rocker mechanism. Practical use. Crank-yoke mechanism For what purpose is the crank-yoke mechanism used?](https://i1.wp.com/chiefengineer.ru/img/mechanics/mehanizmy_preobrazovaniya_dvizheniya.jpg)
The most common mechanisms for converting rotational motion into linear motion are those familiar to us from Fig. 1 crank and according to Fig. 7, d - rack and pinion, as well as screw, eccentric, rocker, ratchet and other mechanisms.
Screw mechanisms
Screw mechanisms are widely used in a wide variety of machines to convert rotational motion into translational motion and, conversely, translational motion into rotational motion. Especially often screw mechanisms used in machine tools to carry out linear auxiliary (feed) or installation (approach, retraction, clamping) movement of such assembly units as tables, supports, carriages, spindle heads, heads, etc.
The screws used in these mechanisms are called running screws. Often also screw mechanism serves for lifting loads or generally for transmitting forces. An example of such an application screw mechanism is to use it in jacks, screw ties, etc. In this case, the screws will be called cargo screws. Load screws usually operate at low speeds, but with greater forces compared to lead screws.
Main details screw mechanism are a screw and a nut.
Usually in screw mechanisms(screw-nut transmissions) the movement is transmitted from the screw to the nut, i.e. the rotational movement of the screw is converted into the translational movement of the nut, for example, the mechanism of transverse movement of the support of a lathe. There are designs where the motion is transmitted from the nut to the screw, and screw gears in which the rotation of the screw is converted into translational motion of the same screw, with the nut fixed motionless. An example of such a mechanism would be helical gear the upper part of the table (Fig. 9, a) of the milling machine. When handle 6 rotates screw 1 in nut 2, secured by screw 3 in table slide 4, 5, screw 1 begins to move forward. Table 5 moves along the slide guides with it.
Eccentric and cam mechanisms
Scheme eccentric mechanism shown in Fig. 9, b. The eccentric is a round disk, the axis of which is offset relative to the axis of rotation of the shaft carrying the disk. When shaft 2 rotates, eccentric 1 acts on roller 3, moving it and the associated rod 4 upward. The roller is returned down by spring 5. Thus, the rotational movement of shaft 2 is converted eccentric mechanism into the forward movement of the rod 4.
Cam mechanisms widely used in automatic machines and other machines to implement an automatic work cycle. These mechanisms can be with cylindrical disk and mechanical cams. Shown in Fig. 9, the mechanism consists of a cam 1 with a groove 2 of complex shape at the end, in which a roller 3 is placed, connected to the slider 4 by means of a rod 5. As a result of the rotation of the cam 1 (in its different sections), the slider 4 receives different speeds of a rectilinear reciprocating movements.
Rocker mechanism
In Fig. 9, d shows the diagram rocker mechanism, widely used, for example, in cross-planing and slotting machines. With the slider 1, on which the support with the cutting tool is attached, a part 4 swinging left and right, called the rocker, is hingedly connected by means of an earring 2. At the bottom, the rocker is connected by means of a hinge 6, and with its lower end it rotates about this axis during swings.
The rocking of the rocker occurs as a result of translational and reciprocal movements in its groove of the part 5, called the rocker stone and receiving movement from the gear 3 with which it is connected. To gear 3, called the rocker gear, rotation is transmitted by a wheel mounted on the drive shaft. The speed of rotation of the rocker wheel is controlled by a gearbox connected to an electric motor.
The stroke length of the slider depends on the type of rocker stone installed on the rocker gear. The farther the rocker stone is from the center of the gear, the larger the circle it describes when the gear rotates, and, consequently, the greater the swing angle of the rocker and the longer the stroke of the slider. And vice versa, the closer to the center of the wheel the rocker stone is installed, the less all the listed movements are.
Ratchets
Ratchets allow you to change the amount of periodic movements of the working parts of machines over a wide range. The types and applications of ratchet mechanisms are varied.
Ratchet mechanism(Fig. 10) consists of four main links: rack 1, ratchet (gear) 4, lever 2 and part 3 with a protrusion, which is called a pawl. A ratchet with teeth beveled in one direction is mounted on the driven shaft of the mechanism. On the same axis with the shaft, a lever 2 is hinged, rotating (swinging) under the action of the drive rod 6. A pawl is also hinged on the lever, the protrusion of which has a shape corresponding to the cavity between the teeth of the ratchet.
During work ratchet mechanism lever 2 begins to move. When it moves to the right, the pawl slides freely along the rounded part of the ratchet tooth, then, under the influence of its gravity or a special spring, it jumps into the cavity and, resting against the next tooth, pushes it forward. As a result of this, the ratchet, and with it the driven shaft, rotates. Reverse rotation of the ratchet with the driven shaft when the lever with pawl 3 is idling is prevented by a locking pawl 5, hinged on a fixed axis and pressed against the ratchet by a spring.
The described mechanism converts the rocking motion of the lever into intermittent rotational motion of the driven shaft.
If we talk about the rocker mechanism, then we should start with the fact that “scene” is a French word that can be translated into our language as “part” or “link”.
general information
From a technical point of view, a rocker mechanism is understood as a device whose task is to convert rotational or rocking motion into reciprocating motion. However, this mechanism can also perform the opposite function. If we talk about the general classification of this device, then it can be of three types - it is a rotating type, a swinging type or a linear one. However, if you understand the essence of the rocker mechanism, it becomes clear that any of its varieties can be classified as a lever type of device. In addition, it is important to note that the work of the slide is carried out in tandem with another part called the slider. This part is also a rotating part in the overall design of the mechanism.
Advantages and material
The main advantage of this mechanism is the provision of a fairly high speed of the slider, which it develops during the reverse stroke. This advantage has led to the fact that such a device has become very widely used in equipment that has idle return. In addition, if we compare a rocker mechanism with a crank mechanism, for example, then the first is capable of transmitting much less force compared to the second.
Most often, a rocker device is used to convert the uniform rotational movement of the crank into rotational movement of the rocker itself as efficiently as possible. It is worth noting that this movement is carried out unevenly. However, there are cases when the movement of the scenes will still be uniform. Most often this happens if the distance between the crank supports and its linkage is equal to the length of the crank itself. In such a system, the rocker mechanism will also be a crank mechanism, which is equipped with a rocker with uniform movement.
Mechanism design and distribution
Today, the most common backstage design is four-link. In addition, all designs of this type can be classified into several groups depending on the type of third link in the device. There are such classes as: two-link, rocker-slider, rocker-rocker, crank-rocker.
These mechanisms are most often used in various types of machines, such as gear shaping, cross-planing and other machines that can be classified as metal-cutting types. The essence of the rocker mechanism is that this is one of the many varieties of the crank mechanism. The use of a mechanism with a rocker is resorted to if there is a need for equipment to convert rotational motion into reciprocating motion. Planing types of machines use a swinging type of slide, and a rotating type of stage is installed.
Four-bar mechanism design
A four-link rocker mechanism with a rocker stone is a system that can be considered on the example of a planer, where this type of device is used. The operation of this system can be described as follows. The crank moves in a circular motion around the axis through the rocker stone, thereby causing the rocker to make a rocking motion. However, at the same time, if you look at the movement of the rocker stone relative to the rocker, it will already perform a reciprocating type of movement. This type of device is also often used in hydraulic pumps that have rotary-type mechanisms with rotating blades. In addition, the four-link mechanism has found its application among various hydraulic and pneumatic drives. In this case, the design involves an input piston on a connecting rod, which slides in a rotating or swinging cylinder.
Rocker-slider mechanism
This mechanism model is most often used in laboratory conditions, and is also used for training and familiarization with this device in educational laboratories in such disciplines as applied and theoretical mechanics.
It is worth saying that the fairly widely used multi-link rocker-slider mechanism is quite large in size. This is due to the fact that the design of the second connecting rod with the slider runs lower than the straight-line arrangement of the rocker rod. This design feature means that the beginning of the connecting rod will be lower than the rocker-lever device itself. This, in turn, suggests that such a mechanism must have a high base or frame, which means that it will be necessary to spend more money on its creation, since excess material is spent on creating such a frame. It is worth noting that it is this factor that is considered the greatest problem and the main drawback of the entire system as a whole.
Rocker-lever device
The rocker-lever mechanism is an invention that has found its application in the field of mechanical engineering. The main task of this system is to convert reciprocating motion into all-wheel drive rotational motion. The purpose for which this mechanism was invented was to increase the service life of the system, as well as to increase its efficiency, or efficiency. In addition, such goals were also pursued as expanding the capabilities in the field of kinematics, due to the fact that the system was equipped with a second slide, and also the links of the system were performed differently.
Crank mechanism
After the invention of this system, it began to be classified as articulated-lever mechanisms that have hydraulic or pneumatic devices, and the purpose of their use was ventilation in warehouses. The design of this mechanism is quite simple, and it contains three main elements: a stand, a crank and a rocker. The task that was set for the inventors of this device was to improve reliability while simultaneously simplifying the design of the mechanism. The prototype for the invention of this model was hydraulic or pneumatic mechanisms, which also used a backstage with translational movement. In addition, the design also included a stand, a slider, and a crank.
Repair
Like any other mechanism, the rocker also has its own service life. After this service life has expired, it is time to repair the rocker mechanism. However, it also happens that the device goes out of service ahead of schedule. Most often in this mechanism, such parts as the slide, rocker stone, gear, screws and nuts for moving the slider, as well as the slider itself with the finger, wear out or wear out. If the surfaces of the slide grooves have been worn by more than 0.3 mm, and there are also deep burrs on them, then milling followed by a scraping operation is used as a repair. If the wear is not too severe, you can get around it only by scraping, without milling.
If the link wears out, then the groove walls are first repaired. When carrying out work, they most often focus on those areas that are less worn than others.
Introduction
1. Transmission mechanisms.
Literature
Introduction
SCENE (French coulisse), a link of the rocker mechanism, rotating around a fixed axis and forming a translational pair with another moving link (slider). Based on the type of movement, there are rotating, swinging, and rectilinear moving scenes.
ROCKET MECHANISM, a lever mechanism that includes a rocker.
Rocker mechanism, a hinge mechanism in which two moving links - the rocker and the rocker stone - are interconnected by a translational (sometimes rotational with an arc rocker) kinematic pair.
The most common flat four-link rocker mechanisms, depending on the type of the third moving link, are divided into groups: crank-rocker, rocker-rocker, rocker-slider, two-link. Crank-and-screw mechanisms can have a rotating, swinging or translational-moving link. Rocker-yoke mechanisms, obtained from the previous ones by limiting the angle of rotation of the crank, are made with a swinging (Fig. 1, a) and translationally moving (Fig. 1, b) rocker,
used to transform movement, and also as the so-called. sine mechanisms (Fig. 1, c) computing machines. Rocker-slider mechanisms are intended to convert rocking motion into translational motion or vice versa, and are also used as a tangent mechanism in computing machines. Two-stage mechanisms are used in machines (Fig. 2),
ensuring equality of the angular velocities of the wings at a constant angle between them. This property is used, for example, in couplings that allow displacement of the axes of the connected shafts. Complex multi-link rocker mechanisms are used for various purposes, for example, in systems for regulating the filling of cylinders of internal combustion engines, reversing mechanisms of steam engines, etc.
1.Transmission mechanisms
Gear mechanisms include planetary and crank mechanisms. These mechanisms allow complex movement.
In a planetary mechanism, rotational motion turns into planetary motion, in which the part rotates around its axis and at the same time around another axis (for example, this is how planets move in space - hence the name of the mechanism).
The planetary mechanism (Fig. 1.a) consists of two gears: driving 1, which is called solar, and driven 4, which is called satellite (there may be several of them). The necessary conditions for the operation of this mechanism are the rigid connection of these wheels using a lever - carrier 2, which gives movement to the satellite, and immobility of the sun wheel 3. The planetary mechanism can be made on the basis of two gears: gear (a, b) with external or internal gearing or chain (c). On the basis of a chain transmission, planetary motion can be transmitted over a greater distance than on a gear basis.
Rice. 2. Planetary mechanisms
The crank-rod (crank-slider, crank-rotary) mechanism serves to convert rotational motion into reciprocating motion (Fig. 2.). The mechanism consists of a leading member of the crank 1, which performs a rotational movement on the shaft, and a connecting rod 2, a slider 3 (b) or a slider, which performs a reciprocating movement. The connecting rod is connected using pin 4 to the working body - piston 3 (a). In Fig. 2.b shows a variant of the crank-slider mechanism, for example, in vegetable cutters.
Rice. 3. Crank-rod and crank-slider mechanisms
2. Front support (TU-4 aircraft landing gear)
The support is located in the forward part of the fuselage. The support niche is limited from above by the floor of the crew cabin, on the sides by longitudinal beams in the form of solid walls with belts along the top and bottom, in front and behind the niche is covered with solid walls of reinforced frames. The niche is closed from below by two side doors, hinged to the longitudinal beams.
The front support strut consists of a shock absorber, in the upper part of which a crossbar with two cylindrical axles on the sides is welded. Using these axles, the stand is hingedly suspended from two units installed on the side beams of the niche (Fig. 6)
The units are detachable and equipped with bronze bushings, to which lubricant is supplied from grease fittings. The trunnions fit into these bushings and are pressed against the body of the unit with caps on bolts. The housing of the wheel turning mechanism is rigidly fixed at the lower end of the shock absorber rod. Inside the housing, a spindle rotates on a roller bearing and a bronze bearing, to which the wheel axles are connected from below using an inclined pipe (Fig. 7.)
The wheels are mounted on these axles with their bearings and secured on the left and right with tightening nuts, followed by locking with cotter pins. When lateral loads are applied to the wheels, the spindle rotates in the mechanism body within the angles limited by stops on the body. The aircraft's turn on the ground is ensured by differential braking of the main gear wheels and free orientation in the direction of movement of the front gear wheels.
A bracket is attached to the front of the spindle, from which a special rod transmits the turning movement of the wheels to a hydraulic shimmy damper. The vane-type damper is bolted to the turning mechanism housing (Fig. 8.)
The spindle's thrust through the lever rotates the roller with movable blades and distils liquid from one cavity to another. Fluid resistance prevents the development of shimmy-type self-oscillations.
To set the wheels in a neutral position after the aircraft lifts off the ground, a spring-roller mechanism for setting the wheels in flight is mounted inside the spindle. It consists of a rocker hinged at the top of the spindle. A roller is installed at the outer end of the rocker, and its inner end, using a vertical rod, presses on a spring fixed in the spindle and having a pre-tension of about 4000 N (Fig. 9.)
Fig.7. Fig.8. Fig.9.
When the wheels turn, the spindle moves the rocker with the roller along the circumference forward or backward, forcing the roller to roll along a profiled cylindrical surface, which is fixed to the body of the turning mechanism. The profile is designed in such a way that any rotation of the wheels from the neutral position moves the roller upward and, compressing the spring, increases the force on the roller. In such a position deflected from neutral, the roller can only be supported by lateral loads on the wheels. After the aircraft takes off from the ground, these loads on the wheels disappear and the spring force forces the roller to roll to the lowest point of the profile, setting the wheels to a neutral position strictly in flight.
The strut shock absorber is liquid-gas plunger type with a needle. The cylinder and the shock absorber rod are connected to each other by a two-link linkage, which prevents the rod from turning in the cylinder.
In the extended position, the rack is held by the rear folding strut. The lower link of the strut is made in the form of a stamped fork, which is attached to the axles on the cylinder coupling. The upper link of the strut is a welded tubular frame, which is attached with its axles to two nodes on the side walls of the niche
The upper and lower links of the strut are connected to each other by a spatial hinge, consisting of an earring and two mutually perpendicular bolts (Fig. 10.) All strut axles are equipped with bronze bushings and lubricant from grease fittings. A screw lift is attached to the upper link of the strut, the second end of which is connected to the gearbox (Fig. 11.)
The bevel gear of the gearbox receives rotation from two independent electric drives, one of which is powered from the emergency network. The rotation of the gearbox gears is transmitted to a steel screw on which a bronze nut is installed (Fig. 12.)
Moving the nut along the axis of the screw with a steel pipe with a forked tip attached to the strut turns its upper link up when retracting and down when releasing the strut. There are two blocks of limit switches installed on the lift body, which turn off the drive in the extreme positions of the rack and ensure its reliable fixation due to the self-braking of the screw pair (Fig. 13.)
The niche doors open when released and close when the rack is removed. In the released position, the flaps are fixed by a rocker mechanism consisting of two hinged levers, the ends of which are attached to the flaps. In the open position of the shutters, the levers are locked with a spring-loaded stopper, which prevents the levers from folding (Fig. 14.)
A cylindrical cam is fixed at the bottom of the shock absorber rod. At the end of cleaning the rack, the cam presses the stopper of the rocker mechanism and unlocks it. With further movement of the rack, the cam forces the levers to fold and turns the doors to close. In the retracted position of the rack, the cam, through levers, presses the doors to the edging of the niche and holds them in the closed position.
Literature:
1. Artobolevsky I. I., Mechanisms in modern technology, t, 1-2, M., 1970
2. Kozhevnikov S.N., Esipenko Ya.I., Raskin Ya.M., Mechanisms, 3rd ed., M., 1965;
A rocker pair is a type of lever mechanism. It converts rotational motion into reciprocating motion or vice versa. In this case, the rotating link may not make a full revolution. Then it is called swinging. The mechanism consists of two main links - the scenes and the slider. One end of the link is fixed on a fixed axis.
The slide is a straight or curved lever with a slot into which the end of another lever slides. It moves relative to the backstage in a straight line. Rocker mechanisms are swinging, rotating and straight.
Crank and rocker mechanisms are capable of providing high speed linear movement of the executive bodies. A typical example of a rocker-type mechanism is the valve control system in automobile engines, the reverse control device for a steam engine, etc.
Rocker pairs are used in metalworking and woodworking machines, where the working element must make multiple linear movements with a return stroke.
Another area of application is analog computing devices, where rocker pairs help determine the values of the sines or tangents of given angles.
Types of rocker mechanisms
Based on the type of moving link of the lever circuit, the following types of rocker pairs are used in installations and moving units:
- Creeper. A lever system consisting of four links. The main parts are a rocker and a slider with a fixed guide. It gives the slider a single degree of freedom to perform linear movements. The swing of the backstage is converted by the device into linear movement of the slider. The kinematic scheme is reversible; reverse transformation of motion is also possible.
- Crank. The crank-rocker mechanism is built according to a four-lever kinematic scheme. Transmits the rotation of the crank to the rocker, which also rotates or swings. Common in industrial installations, for example, in slitting and planing machines. For them, a crank-rocker mechanism with a rotating rocker is used. This design provides a very high forward speed and a slow return. Also used in packaging installations.
- Two-stage. The kinematic four-link design has a pair of scenes. Rotation or swing is transmitted through an intermediate lever. The gear ratio is constant and always equals one. Used in compensating couplings.
- Koromyslovy. It consists of a rocker arm, a rocker and a connecting rod connecting them. Allows the symmetry axes of the motion zones, driving and driven links to be positioned at an angle of about 60°. Finds application in automated production lines
Less commonly used in vehicles and some measuring instruments is a somewhat unique rectilinear guide or conchoidal mechanism.
Design features
The device is one of the subtypes of the crank mechanism. Most rocker pairs are built according to a four-link kinematic scheme.
The third link determines the type of mechanism: two-stage, slider, rocker or crank.
The circuit contains at least two fixed axes and from one to two moving axes.
In the middle of the backstage there is a slot along which the movable axis moves. The end (or other part) of the slider, rocker arm or second link is hinged to it.
Depending on the ratio of lengths at each moment, the executive body can describe both simple trajectories (linear, circular or part of a circle), and complex ones in the form of polygons or closed curves. The type of trajectory is determined by the law of motion of the kinematic pair - a function of the coordinates of the executive body on the angle of rotation of the axis, the position of the slider, or on time.
Operating principle of the mechanism
The principle of operation is based on the basic laws of applied mechanics, kinematics and statics, which describes the interaction of a system of levers having both moving and fixed axes. The elements of the system are assumed to be absolutely rigid, but have finite dimensions and mass. Based on the distribution of masses, the dynamics of the rocker mechanism are calculated, diagrams of accelerations, velocities, and displacements are constructed, and diagrams of loads and moments of inertia of elements are calculated.
Forces are considered to be applied to infinitesimal points.
A lever device that has two moving elements (the rocker and the rocker stone) is called a kinematic pair, in this case a rocker.
Most often, flat circuits of four links are found. Based on the type of the third link of the lever mechanism, crank, rocker, two-stage and slide mechanisms are distinguished. Each of them has its own way of converting the type of movement, but they all use a single trailer of action - linear or rotational movement of levers under the influence of applied forces.
The trajectory of movement of each point of the crank mechanism is determined by the ratio of the lengths of the arms and the working radii of the circuit elements.
A rotating or swinging link of a lever system exerts an influence on a translationally moving link at the point of their articulation. It begins to move in guides that leave this link only one degree of freedom, and moves until it reaches its extreme position. This position corresponds to either the first phase angle of the rotating link or the extreme angular position of the swinging link. After this, as rotation continues or swings in the opposite direction, the rectilinearly moving link begins to move in the opposite direction. The return stroke continues until the extreme position is reached, corresponding to either a full revolution of the rotating link or the second limit position of the swinging link.
After this, the working cycle is repeated.
If the rocker mechanism, on the contrary, converts translational motion into rotational motion, the interaction is carried out in the reverse order. The force transmitted through the joint from the slider is applied away from the axis of rotation of the link that has the ability to rotate. A torque occurs and the rotating link begins to turn.
Advantages and disadvantages of the rocker mechanism
The main advantage of the device is its ability to provide high linear speed of return movement. This property has found application in machines and mechanisms that, due to operating conditions, have an idle return motion. These are primarily slotting and planing machines. The use of a rocker-lever drive mechanism can significantly increase the overall efficiency of the installation, reducing the time for unproductive cycles.
The advantage of two-stage systems used in analog computing devices is their high reliability and stability of operation. They are highly resistant to environmental factors such as vibrations and electromagnetic pulses. This led to their widespread use in target tracking and weapons guidance systems.
The disadvantage of this kinematic scheme is the low transmitted forces. The crank-connecting rod circuit makes it possible to deliver several times more power.
The disadvantage of analog computing devices is that they are extremely difficult or even impossible to reprogram. They can only calculate one predefined function. This is unacceptable for general purpose computing systems. With the development of software and hardware for digital technology, increasing its reliability and resistance to environmental influences, such computing systems remain in niches of highly specialized applications.
Design (production) of the rocker mechanism
Despite the apparent simplicity of the rocker mechanism, in order for it to work effectively, a lot of work is required to calculate and design it. The following main aspects are considered:
- productivity and efficiency;
- cost of production and operation;
- fault tolerance and overhaul life;
- accuracy of action;
- safety.
Considering the complexity of the mutual influence of these aspects on each other, the calculation of the crank mechanism is a multi-stage iterative task.
During the design, the following types of calculations and modeling are carried out:
- kinematics calculation;
- dynamic calculation;
- static calculation.
Typically, design and calculation are divided into the following stages:
- Determination of the required law of motion by calculation-analytical or graphic-analytical method.
- Kinematic modeling. Implementation of the general plan, speed plan, graphical modeling of moments of inertia, graph of energy-mass dependencies.
- Force modeling. Construction of a plan of accelerations, diagrams of forces applied to links in several positions.
- Synthesis of rocker-lever mechanism. Plotting graphs of displacement, speed, acceleration using the graphical-differential method. calculation of the dynamics of the rocker mechanism and its dynamic synthesis.
- Checking for compliance with the law of motion. Final profiling of the wings.
- Checking for compliance with health and safety standards.
- Release of drawings.
For a long time, the calculation and design of the rocker mechanism was a very labor-intensive process that required great concentration and care from the designer. Recently, the development of computer technology and software products of the CAD-CAE family has significantly facilitated all routine calculation operations. The designer just needs to select a suitable kinematic pair or link from the library programs supplied by the manufacturer and set their parameters on a three-dimensional model. There are modules on which it is enough to graphically display the law of motion, and the system itself will select and offer a choice of several options for its kinematic implementation.
Application area
Rocker mechanisms are used in those devices and installations where it is necessary to convert rotation or swing into longitudinal movement or the reverse conversion.
They are most widely used in metalworking machines such as planers and slotters. An important advantage of the rocker-lever mechanism is its ability to provide high speed movement in the reverse stroke. This makes it possible to significantly increase the overall productivity of the equipment and its energy efficiency, reducing the time spent on unproductive, idle movements of the working bodies. A rocker mechanism with an adjustable slider length is also used here. This allows you to best adjust the kinematic scheme based on the length of the workpiece.
The conchoidal type mechanism is used in light wheeled vehicles driven by human foot muscle power - the so-called walker. The person operating the machine, imitating steps, alternately presses the pedals of the mechanism, fixed to the axle at one end. The rocker pair converts the rocking motion into rotation of the drive shaft, which is then transmitted by a chain or cardan drive to the drive wheel.
In analog computers, so-called sine and tangent rocker mechanisms were widely used. To visualize various functions, they use slider and two-stage circuits. Such mechanisms were also used in target tracking and weapons guidance systems. Their distinctive feature was exceptional reliability and resistance to adverse environmental influences (especially electromagnetic pulses) against the backdrop of sufficient accuracy to solve the assigned tasks. With the development of software and hardware of digital technology, the scope of application of mechanical analog computers has greatly decreased.
Another important area of application for rocker pairs is devices in which it is necessary to ensure equality of the angular velocities of the rockers while maintaining the angle between them. Couplings in which partial alignment of shafts is allowed, power systems for automobile engines, reverse devices on a steam engine.