Mechanisms linear motion

Gears are used almost entirely in rotary motion applications, and as such it is easier to discuss the mechanical advantage as a multiplication of torque rather than as a multiplication of force. The work involved in rotary motion is torque times angle whereas for the linear motion discussed above, it is force times distance. 

An actuating cylinder is a device that converts fluid power into linear, or straight-line, force and motion. Since linear motion is back-and-forth motion along a straight line, this type of actuator is sometimes referred to as a reciprocating, or linear motor. The cylinder consists of a ram, or piston, operating within a cylindrical bore. Actuating cylinders may be installed so that the cylinder is anchored to a stationary stmcture and the ram or piston is attached to the mechanism to be operated, or the piston can be anchored and the cylinder attached to the movable mechanism. 

Like rotating machinery, the vibration profile generated by reciprocating and/or linear motion machines is the result of mechanical movement and forces generated by the components that are part of the machine. Vibration profiles generated by most reciprocating and/or linear motion machines reflect a combination of rotating and/or linear motion forces. 

Because of its oscillatory component wave motion requires a related, but more complicated description than linear motion. The methods of particle mechanics use vectors to describe displacements, velocities and other quantities of motion in terms of orthogonal unit vectors, e.g. 

This is the classical-mechanical Hamiltonian for the rotation of a rigid body. [Note the similarity of (5.20), (5.22), and (5.23) to the corresponding equations for linear motion we get the equations for rotational motion by replacing the velocity v with the angular velocity to, the linear momentum p with the angular momentum P, and the mass with the principal moments of inertia.)... 

Mechanical movement action in a die is used to extrude these different profiles such as tubing or strapping with varying wall thicknesses or perforated wall. It is usually accomplished by converting rotary motion to a linear motion that is used to move or oscillate the mandrel. For certain profiles, such as the perforated tubing, the orifice exit would include a perforated section usually on the mandrel. 

Winding machinery comprises (1) a drive mechanism to provide means for imparting simultaneous rotary and linear motion to support structures in a continuous manner, (2) membrane and backing material feeder cartridges, (3) a sealant applicator assembly, (4) electromechanical controls, (5) cut off/separation tooling, and... 

Unfortunately, even sophisticated experiments cannot unravel the detailed microscopic nature or mechanism of the rotational motion of a small molecule in the liquid state. Fortunately, however, one can examine this microscopic aspect of the reorientation of water by employing computer simulations. This method allows one to tag individual water molecules and follow their rotational and translational motion over a period of time by solving Newton s equations of motion. One needs to follow both the orientational and the translational (that is, the linear) motion of the water molecules. When plotted against time, the motion of a molecule over time is called a time trajectory. 

The Cartesian robot consists of three orthogonal linear links that comprise the arm, and three rotational links that from the wrist system. Figure la shows a typical configuration from this robot class. Cartesian robots are easy to control the controller can be seen as very similar to a six-axis machine tool CNC. Unlike all other robots, this type needs no coordinate transformatimis for linear motions. This makes the robot particularly suitable for linear movements where precise path control is required. The drawback of this class is the volume of its mechanical structure relative to the work volume it offers. 

Have you ever wondered how pedaling moves your bicycle Have you ever thought about how the disc tray on your CD player opens and closes These processes and many more are made possible by people designing and controlling devices called mechanisms. A mechanism is a device that transmits movements so that the output movement is different from the input movement. Mechanisms can change the movement s speed, its direction, or its type of motion. Motion can be in the form of linear motion, rotary motion, or reciprocating motion. 

Rack and Pinion A mechanism that converts rotary motion to linear motion is the rack-and-pinion gear (Figure 10-12). If you look at the mechanism that opens the CD drive on your computer, you would find a... 

Lead Screw We can convert rotary motion to linear motion by using a lead screw. This mechanism is not reversible. The metal turning lathe in Figure 10-19 is an example of a lead screw. 

The compressor is a device that increases the pressure of air and pumps the compressed air into a tank. The compressed air tank is called a reservoir. The compressed air is then routed to the desired location through transmission lines. Transmission lines are tubing through which the compressed air flows. Control valves regulate the flow of gases. The pneumatic system uses a cylinder with a movable piston to convert its fluid power into mechanical power in the form of linear motion. 

As with pneumatics, hydraulics uses an actuator called a cylinder to convert its fluid power into mechanical power in the form of linear motion. The advantages gained by fluid power cylinders apply to both hydraulic and pneumatics. 

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. 

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