Crank mechanism

The suction gas which enters from the periphery is trapped by the scrolls. The closed volumes move radially inward until the discharge port is reached, when vapor is pressed out. The orbiting scroll is driven by a short-throw crank mechanism. Similar to screw compressors, internal leakage should be kept low, and is occurring in gaps between cylindrical surfaces and between the tips of the involute and the opposing scroll base plate. 

The reciprocating motion of the piston is transformed into rotaiy motion on the crankshaft by two of the links in the slider-crank mechanism—the connecting rod and the crank (hidden from view in this cross section). The connecting rod joins the piston pin to the crank pin. The crank connects the crank... 

The four-stroke and two-stroke engines described above both use the slider-crank mechanism to transform piston work into crankshaft torque, but other intermittent-combustion engines have been conceived that use different kinematic arrangements to achieve this end. The only one that has realized significant commercial success is the rotary engine first demonstrated successfully in Germany by Felix Wankel in 1957. 

In 1861, Frenchman Pierre Michaux and his brother Ernest invented a bicycle with an improved crank mechanism. They called their bicycle a velocipede, but most people called it a bone shaker because of the jarring effect of the wood and iron frame. Despite the unflattering nickname, the velocipede was a hit. After a few years, the Michaux family was making hundreds of the machines annually, mostly for fun-seeking young people. 

With smaller metering flows spring-loaded cam-drive systems predominate because they make it possible to adjust the stroke without backlash, at a low price (Fig. 4.1-8 h). For larger metering flows (max. hydraulic power up to 25 kW per metering element), various types of drive units with adjustable stroke are in use. All of these are actually based on the familiar conventional crank mechanism (Fig. 4.1-11). 

The pump is a plunger type, suspended in the liquid-nitrogen dewar by means of three long, thin stainless steel bars. A stainless steel rod connects the piston to the crank mechanism. In order to maintain smooth reciprocating motion of the piston in the cylinder, a room-temperature 0-ring is located at the top of the dewar. The crank mechanism is located outside the dewar and operates at room temperature thus, the exhausting rate of the pump is easily controlled by varying the speed of the drive motor. 

Structure Is a set of entities and relatimis among entities cmmected in a meaningful way. Entities are perceived in the form of their attributes when the system is in operation. For example, in Fig. 1 the structure is represented by an electric motor and a crank mechanism. Here, the two possible entities (structures) are the lengths of the bars Lj and L2. 

Principle Is the fundamental law that allows the development of a quantitative relation of the state variables. It governs behavior as the relationships among a set of state variables. For example, in Fig. 1, two possible principles are electromagnetism raling the operation of the electric motor and solid mechanics ruling the function of the crank mechanism. Behavior Represents the response of the structure when it receives stimuU. Since the structure is represented by state and structure variables, behaviors are quantified by the values of these variables. In the case presented in Fig. 1, the two behaviors are Generate torque and Convert torque into force. Function It is about the usefulness of a system. For example, in Fig. 1, one possible function of this system is to compress gas. 

Fig. 9.27 Slider crank mechanism. Reprinted from [Chuc et al. (2010)] with permission,...

The multi-stacked actuator that is introduced in Chapter 7 can generate linear motion like natural muscles. Consequently, it is necessary to transfer the linear motion into a rotational one. Therefore, a simple slider crank mechanism is used to convert the linear motion of the multi-stacked actuator to rotation. The Maxwell stress and the active elastic force of the actuator cause the piston to translate along a vertical axis. This action causes the link to rotate by an angle 0 as shown in Fig. 9.27. 

Employing the slider crank mechanism, a one-DOF mechanism is designed. All parts of this mechanism are illustrated in details in Fig. 9.29. The entire link is manufactured from plastic and aluminum. The upper link can rotate for a maximum angle 65° and the total weight of the fin-... 

The drive system either comprises a crank mechanism with P.I.V. variable-speed drive or variable-speed motor More recently, direct pneumatic drive has been introduced. The grate operating frequency ranges from 3 to 20 strokes per minute... 

Reciprocation. These nozzles are usually placed in an array similar to the fixed system, and the entire array is moved by a cranking mechanism in a direction across the conveyor. Maximmn precision offerings include various patterns of nozzles that can be separately valved and selectively activated by computer controls. 

The carriage includes a crank mechanism for effecting a circular or linear movement of the blades. It is driven in such a manner that the blades scratch... 

The piston is driven periodically by the slider crank mechanism (intermediate mass). This piston acts on the striker through an air bolster. The striker gives its energy to the striking mechanism. The motion is described by the following differential equations... 

Sim96] Simeon B. (1996) Modelling a flexible slider crank mechanism by a mixed system of DAEs and PDEs. Math. Modelling of Systems 2 1-18. 

Fig. 6. The initial, the desired and the resulting curve for the spatial slider-crank mechanism, shown in four view directions.

Figure 7. Impact of a slider crank mechanism with a free block.

Possibly the most widely used linkage requiring kinematic analysis is the basic crank mechanism of the reciprocating internal combustion engine shown diagrammatically in Fig. 2.11, where ... 

Figure 2.11. Internal combustion engine crank mechanism.

The reciprocating high-pressure pump (Fig. 6) is designed to operate at a speed of 240 strokes per minute. Design problems of the various pump elements have been discussed previously. The pump is driven by an electric motor through a gear reduction and a slider crank mechanism. Care must be taken to avoid substantial lateral forces on the plunger. 

Examples of the specific mechanical devices addressed by the document include belts, springs, bearings, seals, brakes, slider-crank mechanisms and clutches. Failure rate models include factors that are known to impact the reliability of the components. 

Avoid configurations that contains a slider-crank mechanism. 

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