Mechanisms Mechanisms.

Mechanisms Mechanisms

Types of Mechanisms Parts handling mechanisms
Reciprocating and general-purpose mechanisms Special purpose mechanisms Spring, bellow, flexure, screw, and ball devices Cam toggle, chain, and belt mechanisms Geared systems and variable-speed mechanisms Coupling, clutching and braking devices Torque-limiting, tensioning, and governing devices Pneumatic machine and mechanism control Fastening, latching, clamping, and chucking devices Several different types of mechanisms are presented in this presentation. These have been classified into the following categories: (Read list)

Parts Handling Mechanisms
Feeding mechanisms Orienting mechanisms Sorting mechanisms Cutting mechanisms Parts handling mechanisms are covered first. This type of device can be further subdivided into devices that orient, feed, sort, cut or select.

Feeding Mechanisms Feeding long cylinders Feeding U-shaped parts
When parts arrive in bulk they often need to be oriented and fed to the next machine. On the left cylinders in bulk are placed in a hopper. The vibrator serves to arrange the cylinders such that their long axes are parallel and help to prevent clogging. The cylinders then drop down a chute where they are fed into a slot in a wheel. The cylinders exit the machine with uniform orientation as long as their ends are the same. If the ends of the cylinders are different then it will be necessary to run them through an orientation mechanism. This is shown on the next slide. On the right u-shaped pieces lie in a randomly oriented pile. The rotary centerblades catch the parts and as the centerblades are indexed, the parts slide off of the centerblades and onto the blade feeder. Feeding long cylinders Feeding U-shaped parts REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Feeding Aligning Parts
Now that the parts are properly oriented it is necessary to feed them to the next machine one at a time. Reciprocating linear motion is used for feeding parts in A through C. Angular motion and gravity are used to deliver parts in D and E. A star feeder with or without dwell periods feeds parts in F. A belt conveyer and an angular motion device separates individual cylinders in G. Various mechanisms for feeding aligned parts REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Feeding a certain number of parts
Special Feeders It is sometimes necessary to feed a certain number of parts to the next machine. The examples shown on the left feed one and three parts at a time, respectively. At other times it is necessary to mix different parts together. The figure on the right combines donut-shaped parts with solid parts. Feeding a certain number of parts Mixer REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Orienting Mechanisms Orienting pointed-end parts
Parts often arrive at a particular machine with non-uniform orientation. This common problem can be overcome with the use of an orienting machine. Two examples of these mechanisms are shown. On the left, parts with one pointed end and one flat end arrive but some parts arrive with the pointed end first and others do not. It is desired to have all the flat ends exit the machine first. The parts enter the slots on the wheel and then the wheel is rotated clockwise. The magnet can hold the part only if the part’s flat end is facing the magnet. So the parts with the pointed end facing the magnet, slide through the chute and exit the machine flat end first. The parts with the flat end facing the magnet are kept from falling through the chute and ride the wheel to the exit and then fall out the machine with the flat end first. On the right u-shaped parts need to have uniform alignment. Pin 2 obstructs the chute as the parts fall down, holding the part on top of pin 2. Then pin 1 moves into the chute. If the u is facing right, it does not hit the part and when pin 2 is withdrawn, the part continues down the chute. If the u is facing left then pin 1 hits it and it falls around the teardrop-shaped obstruction. The u is now facing right and the part continues down the chute. Orienting pointed-end parts Orienting U-shaped parts REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Orienting Mechanisms, cont.
Both of these devices orient short cylinders with one open end and one closed end. The device on the left uses a lever that catches the open end of the cylinder and flips it. The closed end, however, will slip past the lever without being flipped. The device on the right uses a pin to accomplish the same task. The closed end hits the pin without being caught and flipped by it. Orienting short cylinders REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Sorting Devices Sorting balls by size
Balls run down two slightly divergent rails in the device shown in A. The smallest balls fall into the left chamber, the medium sized balls fall into the middle chamber, and the largest balls fall into the right chamber. The device shown in B accomplishes the same task. Balls with a smaller diameter pass under the gate without hitting it and fall into the chamber on the right. Balls with a larger diameter hit the gate which releases the trapdoor, causing the ball to fall into the chamber on the left. Sorting balls by size REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cutting Mechanisms Four-bar cutters
There are many different types of cutters. The ones presented here are all four-bar cutters. These provide a stable, strong, cutting action by coupling two sets of links to obtain four-bar arrangements. Four-bar cutters REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cutting Mechanisms, cont.
This device clamps the material before cutting. When the foot pedal is pressed, the top knife is brought down forcing link EDO counter-clockwise until the clamp presses down on the material. As the foot pedal is depressed further the top knife continues down and link ABC rotates, causing the top and bottom knife to cut the material. Clamping and cutting device REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cutting Mechanisms, cont.
The motion of the slicing mechanism shown is due to the two eccentric disks attached to the input shaft. The two loops are welded together such that one eccentric disc actuates each loop. In the position shown, the bottom disk causes horizontal motion of the slicer, while the top disk moves the slicer up and down. Slicing Mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Reciprocating and General Purpose Mechanisms
Geneva mechanisms Hypocycloid mechanisms Rotary to reciprocal devices Dwell mechanisms Escapement mechanisms Reciprocating and general purpose mechanisms are covered next. This type of device can be further subdivided into: (Read list) REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Geneva Mechanisms Locking-arm geneva Twin geneva drive
It is often necessary to move intermittently. Geneva mechanisms are often used to accomplish this task. The input shaft of this type of mechanism is generally driven with a constant velocity. For every full rotation of the input shaft, the output shaft only turns a portion of a rotation. It is generally desirable for the output shaft to remain motionless for a period of time. This is called dwell. On the left, a locking-arm geneva is shown. Here a spring-loaded locking-arm is used to prevent rotation of the output shaft when the input crank is not rotating the output shaft counter-clockwise. A cam on the input shaft is used to disengage the locking arm when the driving roller on the input crank enters the slots. On the right, the driven member of the first geneva acts as the driver for the second geneva. This allows a wide variety of output motions including very long dwells between rapid indexes. Twin geneva drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Geneva Mechanisms, cont.
Basic geneva mechanisms have high acceleration of the output geneva during indexing. The groove cam geneva, shown on the left, reduces this acceleration by placing the driving roller on a link that rotates with the input shaft. As the roller enters a slot on the geneva, the cam pushes the link and roller closer to the rotational center of the input shaft. This decreases the acceleration of the geneva. A similar method of changing the radial position of the driving pin is shown on the right. Here the position of the spring-loaded driving pin is varied using a cam. Groove cam genevas REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Locking-slide geneva On the left, the locking-slide geneva shows a second method by which the geneva can be locked in place when it is not being indexed forward. On the right a four-bar linkage makes the driving roller and locking disks oscillate as the input shaft is rotated. The resulting output is an oscillation of the output shaft with long dwell periods. Four-bar geneva REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The rapid transfer geneva on the left uses a four bar linkage to move the driving pin along the path shown. Notice that the driving pin moves the geneva output only during the curve on the upper right corner of the path of the driving pin. This means that the geneva is indexed forward quickly. The gears drive a locking cam to prevent motion of the geneva when it is not being indexed. A long dwell geneva mechanism is shown on the right. The long dwell is obtained by placing the driving pin on the chain. Rapid transfer geneva Long-dwell geneva REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The modified motion geneva, on the left, uses elliptical gears to vary the motion of the driving pin and therefore the output geneva. This allows one to design for various dwell periods and output geneva accelerations. The dual-track geneva shows another method by which the driving pin can enter and leave the slots on the output geneva tangentially. In this case there are two tracks – one used while entering and one used when the driving pin exits the slot. Modified motion geneva Dual-track geneva REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Another indexing mechanism, the internal-groove geneva, is shown on the left. The input crank enters and exits the geneva output tangentially. Notice that no locking is present to prevent motion of the geneva output. On the right, the progressive oscillating drive provides two dwell periods during one revolution of the input crank. As the input crack is turned, the pin on the driving link attached to the planet gear describes the path shown. The output link will oscillate at each dwell period rather than being held stationary. Internal-groove geneva Progressive oscillating drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

A planetary gear geneva mechanism is shown on the left. The ring gear is held stationary while the planet gear rotates about the input gear. The dwell periods can be altered by placing the driving pins non-symmetrically on the input shaft as shown in the mechanism on the right. Planetary gear geneva Modified dwell period geneva REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The modified geneva mechanism shown uses two rollers on the input crank, one acting as a locking mechanism while not being driven by the other pin. The output shaft indexes twice during each rotation of the input shaft. The angle, theta, that the output shaft rotates during each index is determined by the number of teeth on the output gear. Modified geneva REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Intermittent Mechanisms
The intermittent mechanism on the left indexes the output shaft forward each revolution. The duration of the indexing motion depends on the distance between the locking disks and the length of the angular joint. On the right, a cam operated escapement used on a taximeter is shown. Intermittent drive Indexing mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Hypocycloid Mechanisms
One of the advantages of the cycloid mechanisms is that one of three common motions can be produced. The ring gear is fixed and the input crank forces the planet gear to rotate about point O1 while revolving around point O2. The figure on the right shows the basic hypocycloid motions that may be produced. Point P1, a point on the interior of the planet gear, traces out a diamond-shaped curve. Point P2, a point on the edge of the planet gear, traces a cusp curve. Finally, point P3, an external point that moves with the planet gear, produces the loop curve as shown. The figure on the right takes advantage of the diamond-shaped curve obtained by a pin mounted on the planet gear. The resulting motion causes the output link to oscillate horizontally with long dwell periods at the extreme positions. Basic hypocycloid curves Double-dwell mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Hypocycloid Mechanisms, cont.
The long-dwell geneva mechanism takes advantage of the same diamond-shaped curve shown previously. But, in this case, the output is a geneva mechanism with a locking cam. As with other four-station genevas, the output geneva is indexed forward by 90 degrees during each revolution of the input. However, since the driving pin moves along a non-circular path, a smoother indexing motion results. On the right an internal-geneva drive is shown. Here a loop-type curve is produced by attaching a link to the planet gear. The pin attached to this link drives the output geneva. The pin enters the slots tangentially and then rapidly indexes the geneva by 90 degrees before going into a long dwell period while the input rotates 270 degrees. Internal-geneva drive Long-dwell geneva drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

A short-dwell mechanism is shown on the left. The planet gear has a pitch circle four times smaller than the ring gear and the driving pin is placed on the addendum circle, the outermost portion of the planet gear’s tooth, so that a diamond-type curve is produced. This results in short dwells four times per revolution. A slight variation of this mechanism, shown on the right, is obtained by attaching a linkage to the driving pin. The resulting motion has two dwell periods, one between 0 and 90 degrees and the other between 180 and 270 degrees. Short-dwell rotary Cycloidal rocker REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The previous hypocycloid mechanisms shown had a 4 to 1 gear ratio. If the pitch diameter of the planet gear is half that of the ring gear, elliptical curves are obtained. If the driving pin is placed at P1, a circle is produced. Pins placed P2, P3, and P4 all result in ellipses. The ellipses flatten as the driving pin is placed further from the center of the planet gear. Elliptical-motion drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Rotary to Reciprocation Motion
Scotch yoke The most familiar mechanisms for converting rotary motion into translation are the scotch yoke and the slider crank. On the right a four-bar slider mechanism is shown along with a space-velocity graph for the slider. The velocity is along the y-axis and the position of the slider is along x-axis. Notice that this mechanism has been designed such that the slider moves at an almost constant velocity for a large portion of its stroke. Four-bar slider mechanism Slider crank REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Rotary to Reciprocation Motion, cont.
As the input gear of the mechanism on the left rotates, the middle gear is forced to rotate and since the connecting link is attached to the frame, the link connecting the gears oscillates. The slider’s motion is amplified by the fact that the slider is (indirectly) connected to the link connecting the gears beyond the middle gear. Also, the slider’s connecting rod is attached to the third gear such that it is 180 degrees out of phase with the middle gear’s connecting rod. The linear reciprocator on the right converts the rotary input motion to linear oscillation that is in-line with the input shaft. Linear reciprocator Three-gear stroke multiplier REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

On the left, the rotating input shaft causes the surface of the truncated sphere to rotate. The output link has rollers that remain in contact with the sphere’s surface causing that link oscillate sinusoidally. On the left, reciprocation is developed by rotating a cam, forcing the surrounding block the reciprocate vertically. Notice that the block is able to move within its frame horizontally without any resulting horizontal motion of the frame. Rotating-cam reciprocator Spherical input reciprocating drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Screw drive The mechanism shown in the upper left-hand corner has a rotary input which is converted to translation using a screw thread. In this case the translation of the output is directed along the axis of the input shaft. The mechanism on the lower left also uses screw threads to convert an input rotation into translation. However, in this case an inclined plane is implemented so that the output motion is not directed along the axis of the input shaft. Notice that the direction of the output motion can be directed at any angle with respect to the axis of the input shaft. Translation may also be converted into rotation by using a screw thread with a large pitch as shown on the right. Translation to rotation mechanism Screwed inclined mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Dwell Mechanisms Oscillating crank and planetary drive
The oscillating crank and planetary drive is shown with the driving roller entering the arced slot in the planet link. As the input sun gear rotates, the driving pin traverses the arced slot without rotation of the planet link. This means that as the planet gear rotates the output ring gear will also rotate clockwise. During the rest of the sun gear’s rotation, the motion of the ring gear oscillates once, creating the dwell period. On the right a hypocycloid mechanism with the drive pin located at the edge of the planet gear results in epicyclic curve as shown. By making the length of the connecting rod the same as the radius of curvature of the epicyclic curve, a long dwell results as the input crank rotates from positive 60 degrees to negative 60 degrees. The makes the output crank oscillate left and right with a long dwell at its right hand position. Oscillating crank and planetary drive Epicyclic dwell mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Dwell Mechanisms, cont. Chain-slider drive Cam-helical dwell mechanism
The Chain-slider mechanism is driven by the input shaft at constant velocity. The output reciprocating shaft moves at constant velocity between dwell periods that occur when the chain lever rotates about the gears. This dwell periods last 180 degrees. The input shaft is geared to the intermediate shaft which is geared to the output shaft causing rotation at a constant speed. But a cam on the input shaft drives a pin in the intermediate shaft causing horizontal oscillation. This oscillation causes a rotation of the output shaft which adds or subtracts from its otherwise constant speed rotation. Cam-helical dwell mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Dwell Mechanisms, cont. Cam-roller dwell mechanism
The steel strip in the cam-roller dwell mechanism is fed to the left at constant velocity. But it is desired to a zero velocity during the punching process. This is accomplished by driving a cam which moves the rollers to the right during while the steel is being punched. The pin connection of the gear oscillating crank has the path shown. Two portions of this path, C1 and C2, are close to circular. This creates dwell periods as the connecting pin traverses these portions of the curve. Gear oscillating crank REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Dwell Mechanisms, cont. Three-gear drive Gear-slider crank
The three-gear drive combines a four bar linkage and gears to impart motion of the output gear. The output gear can be made to pulsate, have a short dwell period, or reverse directions depending on the relative gear ratios. The connecting pin of the gear-slider crank traces the path shown. This makes the piston’s velocity vary with a dwell periods at each end of the stroke as shown. Three-gear drive Gear-slider crank REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Toothless Ratchets Helical spring ratchet Flat spring ratchet
The helical spring ratchet grips the shaft on the forward stroke, but loosens on the reverse stroke. The flat spring ratchet uses the same principle for its ratchet motion. Helical spring ratchet Flat spring ratchet REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Toothless Ratchets, cont.
The cam ratchet also allows motion in one direction only. The cam wedges against the disk when rotating in the blocked direction. The elongated hole gives extra support to allow increased blocking by the cam. Cam ratchet REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Escapement Mechanisms
Escapement mechanisms are used to interrupt the motion of a gear train at regular intervals. They are often used in watches and clocks. As shown, the motion of the pin wheel is currently blocked by pallet A. But as the pendulum swings to the left, pallet A releases the escape wheel and allows it to rotate until the pin is in contact with pallet B. Pallet B keeps the wheel from rotating further until the pendulum swings to the right, allowing the pin to escape. The next pin is then captured by pallet A and the process continues. The anchor shown uses the same idea to absorb the energy of the wheel in order to interrupt its motion. The only difference here is that the impact surfaces are shaped so as to eliminate recoil of the escape wheel. Pin wheel Anchor REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Special Purpose Mechanisms
Straight line motion Changing straight line direction Expanding and contracting devices Linear Acceleration Linkages for multiplying short motions Parallel-link mechanisms Adjustable output mechanisms Computing mechanisms Special purpose mechanisms include: REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Straight Line Motion Peaucellier cell Watt’s linkage
Linkages that provide straight line motion without using guides were developed to replace slides and telescoping devices when minimal friction was required. The Peaucellier cell was the first linkage developed to provide straight line motion without slides or telescoping devices. It can be shown that for this linkage and the proper link lengths, AC times AF is a constant. If point C has a circular path passing through point A, then point F will move along a straight line. Watt’s linkage, shown on the right, traces out a figure eight. The straight line portion is straightest and longest when the connecting link length is about two thirds of the stroke, S, and the arm length is three halves the stroke length. If the arms are of unequal length, then the figure eight will not be symmetrical and one portion will be straighter than the other. Peaucellier cell Watt’s linkage REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Straight Line Motion, cont.
Evan’s linkage shows a similar device to approximate straight line motion. Notice that if PB is equal to BA and BC, then P will only traverse a straight line if C remains on the dashed line from A to C. Since link CD must be finite, point C will deviate from this line and point P will also deviate from straight line motion. Tchebicheff sought to improve upon the Evans linkage by forcing point C to follow a straight line. For this, he used Watt’s linkage which consists of links EF, FG, and GD in the right-hand figure. Tchebicheff’s linkage, a combination of Watt’s and Evan’s linkages, is shown in the figure on the right. Evan’s linkage Tchebicheff’s linkage REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The linkage, shown here in simplified form, was developed and patented by James Daniel. This type of linkage has been used in cameras. On the left the linkage alone is shown, while the figure in the middle shows the paths of Daniel’s linkage. Notice that both points P and Q travel in a straight line as link CD is rotated. A parallel configuration of Daniel’s linkage is shown on the right. The advantage of this type of arrangement includes the increased rigidity provided by an extra set of pivots and the straight line motion of a bar rather than just a point. Daniel’s linkage Path’s traced by Daniel’s linkage Parallel linkage REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The figures above show the action of Daniel’s linkage and that beyond the linear region its deviation from a straight line is great. Long-kick mechanism Short-kick mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Hypocycloid drive The hypocycloid drive or cardan shown earlier may be used to convert rotation into straight line motion as long as the diameter ratio of the inner and outer gears are one to two and the driving pin on the inner gear is placed at its pitch radius. The length of the resulting oscillation is equal to the pitch diameter of the outer gear. The hypocycloid drive can be used to drive a scotch yoke mechanism in order to obtain an adjustable stroke length of the output shaft. The output stroke length is adjusted by rotating the ring gear, thereby rotating the straight line along which the driving pin on the planet gear traverses. While this mechanism does have a slide, it is included here do to the similarity to the hypocycloid drive. Hypocycloid and Scotch yoke drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Parallel cardan mechanism The ringless hypocycloid drive is shown to demonstrate that the costly ring gear can be eliminated if an idler gear of the appropriate size is inserted. The gear ratio between the sun gear and the planet gear is kept at 2 to 1. Notice that this arrangemnt allows a large output stroke for the given gear sizes. The cardan mechanism can be modified such that an arm attached to the planet gear remains parallel as the planet rotates about the sun by making the gear ratio between the sun and planet gears a 1 to 1 ratio. Ringless hypocycloid drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Changing Straight Line Direction
There are a number of ways to change straight line direction. The first method shown here uses a linkage and the second uses guides. Linkage drive Guided drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Changing Straight Line Direction, cont.
Friction drive The next method uses friction, where a steel band is attached to each shaft in order to change the direction of displacement. A geared drive may be used to accomplish the same task. Geared drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Articulated rod drive Another method of changing the direction of motion is by attaching an articulated rod to the input shaft. The other end of the articulated rod is attached to a gear which drives a rack. An articulated rod fixed to a cam can transmit movement to a follower in any direction. Cam and follower drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

A fluid coupling can be used to alter the direction of motion but this method is generally not cheap since good seals are necessary. If only two extreme positions are required then the pneumatic system shown may be used. Fluid coupled drive Pnuematic drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Expanding and Contracting Devices
Expanding grill Telescoping cylinders Several mechanisms are shown which may be used for adjustable devices such as table extensions or storefront gates. Multibar linkage Nested slides REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cam Replacements Adjusting oscillation Curved flange
At times a cam and follower cannot be used. These linkages may be used as a replacement. The oscillatory input motion of the slide block can be adjusted by using the figure on the right. The pinion and its offset drive pin connected to link D are the main cause of the difference between the motion of the input and the output along link F. Another possible replacement for a cam-follower is the curved flange. Here a slide block has a curved flange attached to it. As the input slide block is moved, the rollers attached to the output slide block follow the flange and vertical motion results. Curved flange REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cam Replacements, cont. Bellcrank mechanism Stepped sheave-cable
The input motion along the drive rod of the bellcrank mechanism causes the curved wedge to separate the bellcranks and drive the slide block forward. The linkages and the shape of the curved wedge can be altered to achieve the desired motion. Note that a spring nust be used to return the bellcranks to their closed position. The second mechanism, shown on the bottom, is driven by a rod connected to a slide block. As the slide block moves forward, sheaves engage a cable forcing the driven slide block to the left. Since the sheaves are stepped, the output motion of the slide block will be as well. Stepped sheave-cable mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Linkages for Multiplying Short Motions
This mechanism is used is differential pressure gauges. The two pressures are applied separately to bellows. The bellows are spring loaded so that high pressures can be applied. The pressure applied to the bellows results in a force on the rod conned tot eh differential pressure lever. A larger pressure applied to the right-hand bellows causes the lever to rotate counter-clockwise. This forces the sector gear to move down and the needle to rotate clockwise. Lever and sector gear REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Linkages for Multiplying Short Motions, cont.
Lever, cam, and cord transmission Barometers often use the lever, cam, and cord transmission shown. As atmospheric pressure changes, the gas in the bellows expands or contracts. As this happens, the deflection of a bellow is amplified by a lever which drives a cam. The cam, in turn, pulls on a spring-loaded cord that is wrapped around a shaft. A pointer indicating the barometric pressure is attached to this shaft. In the lower figure, another system used to measure barometric pressure is shown. Again, the deflection of the bellow is amplified using a lever. In this mechanism two bellows are used to further increase the deflection of the lever. The deflection of the lever is further amplified by the linkage and pointer used to indicate the atmospheric pressure. Lever system REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Linkages for Multiplying Short Motions, cont.
The toggle and cord drive can be used to measure fluid pressure. The fluid pressure deflects the bellows which, in turn, alters the degree of buckling in a beam with one end attached to the center of the bellows and the other end fixed. This setup amplifies the deflection of the bellows. A spring loaded cord is attached to the beam center so that its buckling is transmitted to a shaft with a pointer attached. The spiral feed transmission again uses a lever to amplify the deflection of the bellows. However, this time the lever drives a threaded shaft with a low pitch, forcing the shaft to rotate. A pointer is attached to the shaft to display the output reading. Toggle and cord drive Spiral feed transmission REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Stroke Multipliers Reciprocating-table drive Pulley drive
The crank on the reciprocating table drives two gears rolling on a stationary bottom rack. The output rack rides on top of the gears. The output rack oscillates a distance four times the input crank radius. In the lower figure, a hydraulic cylinder drives a pulley train, which drives the output slider. The pulley system multiplies the stroke of the hydraulic cylinder. Pulley drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Stroke Multipliers, cont.
For the angle-doubling drive shown, an input rotation of 90 degrees is converted into a rotation of 180 degrees on the output link. For a particular set of links, the distance between the input and output shafts determines the multiplication factor between the input and output rotations. The gear-sector drive consists of a four bar linkage with an attached gear sector driving the output gear. The four bar linkage is used to obtain oscillatory motion. The gear-sector is used to multiply the stroke of this oscillatory motion. Gear-sector drive Angle-doubling drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Parallel Linkages Tensioning mechanism Eight-bar linkage
Two four bar linkages with equal length links on opposing sides are used in the eight-bar linkage. Link AB remains parallel to the frame and link CD remains parallel to link AB. Also due to the proportions of the links, link CD produces virtually straight line motion. Note the similarity to the parallel linkage used to produce straight line motion on slide 41. The tensioning mechanism uses parallel links to ensure uniform force applied along the web. The applied force can be adjusted by moving the weight. This type of device is often used to apply tension in webs, wires, and tapes. The last figure shows a triple-pivot mechanism used to round the edge of grinding wheels into a circular arc. Note that the checkered points are fixed pivot points. Since parallel linkages are used, the circular path traced out as the two triangular plates rotate about the fixed pivots is mimicked by the diamond cutter. Triple-pivot mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Adjustable output mechanisms
It is sometimes necessary to have an adjustable output. The length of the stroke of the adjustable slider drive can be altered by changing the distance between the pivot point of the slotted link and the input crank’s pivot. The input and output shafts of the adjustable chain drive can be synchronized by changing the position of the idler pulleys. Adjustable slider drive Adjustable chain drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Adjustable output mechanisms, cont.
Adjustable clutch drive As the input crank rotates the rocker oscillates and the one-way clutch transmits motion to the output shaft in only one direction. Changing the pivot point of the slider-cylinder affects the degree of rotation of the rocker. The valve stroke adjuster works in a similar manner. By changing the pivot point of link AB, the stroke of the valve is changed. Valve stroke adjuster REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Adjustable output mechanisms, cont.
By keeping the position of the adjusting shaft constant, the rotation of the input shaft of the differential mechanism is transferred through the bevel gears to the output. But rotating the adjusting shaft about the axis of the input and output shafts alters the rotation of the output shaft. As the input crank of the mechanism on the right turns, the piston oscillates back and forth. The stroke of this oscillation can be altered by rotating the eccentric shaft and therefore the pivot point. Differential Eccentric pivot point REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Rolomite, Bellow, and Flexure Devices
This section covers spring, bellow, and flexure devices. REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Rolomite devices a b c Basic Rolomite device d
Rolomite devices consist of a flat metal band and two rollers. Since there is virtually no sliding friction, the rollers move easily when pushed. It’s coefficient of friction is , which is less than 10% that of a ball in a roller bearing. When the metal band is bent into an S-shape, as shown, elastic energy is stored. If the band is uniform with a constant width, then the device is in equilibrium and the rollers remain stationary. However, as shown in the figures on the left, many force profiles may be obtained by varying the shape of the metal band. Figures b and d show the band shape required to obtain a constant force over a portion of the device’s stroke. In order to get a constant force over the entire range of the device, the band is tapered as shown in figure c. The resulting behavior is that of a spring. The force profile can be produce by varying the shape of the band, using a pre-stressed metal band, or using a bimetallic strip. The bimetallic strip band can be used to produce a thermostat. Rolomite devices are inexpensive, do not require lubrication or precise tolerance, and are relatively unaffected by dirt. d Some possible force profiles REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Rolomite devices, cont. Rotary bearing Moving table suspension
A few possible mechanisms using the rolomite device are presented here. These include a rotary bearing, speed reducer, moving table suspension, and a fluid pump. Other possible mechanisms not shown are a acceleration-activated snap-action switch for air bags, a door hinge, and a thread gage. Speed reducer Fluid pump REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Flexure Devices Flexure connection Cross-strip pivot Pivots
Flexure devices are simple, have little friction and wear, and do not require lubrication. Flexure pivots can replace the bearing that would be required at the connection of two links. Pivots can be made using two strips of flexible material as shown. Flexible material can also be used to replace a rack and pinion. Pivots Rack and pinion equivalent REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Flexure Devices, cont. Universal joint Parallel motion linkage
Flexure material can be used to produce parallel linkages or a universal joint. A flexible strip can be attached to two shafts to transmit motion for low torque, small rotation applications. Multiple skewed strips of flexure can be used to convert rotary motion into translation. Rotary to translation converter Flexure transmission REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Bellow Devices Linear translation Reciprocating rotary motion
Bellows can be used to actuate mechanisms. By pumping air into the bellows, linear or rotary actuation can be obtained. Linear translation Reciprocating rotary motion REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cam, toggle, and belt mechanisms
Cams Toggle mechanisms Variable speed belt drives Connecting misaligned shafts This section covers cams, toggles, variable speed devices, and mechanisms for connecting offset shafts. REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cams Simple follower Forked follower
Cams may be used to guide the position of a follower in some repeating pattern. While cams have the advantage of being able to produce numerous patterns, care must be taken in order to avoid inducing vibration. This can be handled to some extent by the type of follower. Two types of followers are shown here. The first follower is simple, while the forked follower is better at avoiding vibration. Simple follower Forked follower REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cams, cont. Clamping cam Barrel cam
The clamping cam shown is double eccentric and imparts a large holding force. The barrel cam is often used in sewing machines to guide the thread. Barrel cam REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cams, cont. Sewing machine cam Swash plate
The slot cam can be used to convert oscillatory rotary motion into straight-line motion. The slot cam shown here converts non-oscillatory rotation into reciprocation of the slide and is used on sewing machines and printing presses. Another type of cam is the swash plate, which is suitable for light loads only. The swash plate is used with multiple followers in one type of positive displacement pump. Sewing machine cam Swash plate REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Cams, cont. Hammer drill cam
The hammer drill cam is used to induce axial vibration to the drill bit to enhance boring through masonry and concrete. Hammer drill cam REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Toggle Mechanisms Simple toggle Locking latches
Many linkages employ a toggle which occurs when links the line up. At toggle the velocity ratio, VA/VB, and mechanical advantage become very large. Locking latches use the toggle to provide a large force in the locked position. The locked position is slightly beyond toggle so that a small force must be applied in order to unlock the latch. Locking latches REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Toggle Mechanisms, cont.
Punch presses require large forces at the lowest extreme of the stroke, but little force during the remainder of the stroke. Conveniently, the crank and connecting rod come into toggle just when the large force is required. The rivet machine starts at 1, comes into toggle at 2, rotates further to position 3, and then domes into toggle again at position 4. The crank then returns to position 1 to allow clearance for removal of the part. The machine is designed such that the toggle positions occur when large force is required. Punch press Rivet machine REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Toggle Mechanisms, cont.
The stone crusher has two toggle linkages. The first occurs when the crank reaches the top of its stroke and it comes into toggle with link. At the same time link three comes into toggle with link four. The resulting mechanism has a very high mechanical advantage. The friction ratchet is designed to allow rotation in one direction but not the other. Counterclockwise rotation pushes the brake and link two further from the toggle position and is thus allowed. Attempted rotation in the clockwise direction results in arms one and two approaching the toggle position and a large braking force. Stone crusher Friction ratchet REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Latch Mechanisms Toggle latch Double toggle latch Pin A
The two latches use toggles. The simple toggle latch is unstable in its toggle position and comes into equilibrium when the cocking lever comes into contact with either of the stops. The same is true of the double toggle latch. The difference here is that the lower link rotates about pin A until it comes into contact with the stop. This type of latch is often used in electrical switches. Toggle latch Double toggle latch REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Latch Mechanisms, cont. Latch and cocking lever
A couple more latching mechanisms are shown. In both cases the cocking lever will remain in position until it is unlatched. Latch and cocking lever Disk-shaped cocking lever REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Latch Mechanisms, cont. Firing pin mechanism
As the trigger on the firing pin mechanism is squeezed, the latch is forced down and the cocking spring compresses. This continues until the latch is forced down far enough to allow the beveled collar to pass and a sudden release of the firing pin. When the trigger is released the reset spring pushes the trigger and firing pin back into the cocked position. Firing pin mechanism REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Variable Speed Mechanisms
Variable pitch pulleys can be used in variable speed mechanisms. The speed is varied by varying the pitch diameter seen by the V-belt. As the inner and outer disks of the sheave are separated, the pitch diameter seen by the v-belt decreases. There are four basic methods by which the pitch of the sheaves are controlled. These include: springs, cams, linkages, and centrifugal forces. Both the spring-controlled and the cam-controlled variable pitch pulleys are shown. Cam controlled variable pitch pulley Spring controlled variable pitch pulley REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Variable Speed Mechanisms, cont.
The cone drive works without gears or pulleys and is directly connected to the engine. The inner cones mounted directly to the drive shaft are made of brake lining material. Disks on the output shaft contact the cones causing the output shaft to turn. The speed of the output shaft depends on the contact location between the cone and the disk. The bearings on the output shaft are mounted on a pivoting frame whose movement controls the contact location of the cone and disk. Cone drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Adjustable cone drive Two cone drive The adjustable cone drive can change speed simply by changing the location of contact between the cone and wheel. As this contact location moves to a point where the radius of the cone is larger, the speed of the output shaft increases. The two cone drive works similarly except that the wheel is used intermediately between two cones, one on the input shaft and one on the output shaft. The Cone-belt drive transmits motion between two cones by using a belt. These transmissions allow continuously varying speeds, but have limited speed ranges and generally must be spring loaded to reduce slippage. The contact area between the wheel or belt and the cone must be wide enough to transmit the required torque, but must be thin enough to minimize a large speed deferential across its width. Cone-belt drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The graham drive is a combination of the cone drives shown previously and planetary gears. The input shaft is connected to the planets and the output shaft is connected to the sun. The ring gear is held stationary rotationally but is able to move along the axis of the shafts. The contact position of the ring gear and the tapered roller planet gears determines the speed of the sun gear. Graham drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

The disk drives shown work just like the cone drives shown before except that the cone is replaced by a disk. Single disk drive Double disk drive REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Connecting Misaligned Shafts
This mechanism consists of three disks and six links. The torque transmitted is constant regardless of the angle of rotation. The offset between the shafts can be changed during operation. The inventor of this coupling, Richard Schmidt, said that German Engineers had known of it for years but never used it because they incorrectly thought that the center disk needed to be housed in a bearing. Possible applications include drive shafts, steering columns, and coupling inboard motors on boats to their propellers. REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Connecting Misaligned Shafts, cont.
Square plate coupling used for angular misalignment Square plate coupling This coupling allows for both angular and offset misalignments while allowing the transmission of high torque while maintaining a constant velocity. Unlike other flexible couplings, the square plate coupling virtually eliminates rubbing between parts of the coupling. This means that no lubrication is required and an increased efficiency. Square plate coupling used for offset shafts REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Connecting Misaligned Shafts, cont.
Flexible shafts are an easy method for power transmission from one location to another. They are movable, have an efficiency as high as 90% and dampen vibration. However, when transmitting large torques, they have a relatively high torsional windup. Heavy duty shafts allow can transmit up to 20 horsepower and the smaller shafts can rotate up to rpm. Flexible shafts are made of three elements: the core, the flexible housing, and the core-end fittings. The core consists of many layers of wire wrapped around a single wire. The direction of the wrapped wire layers alternates and the size and number of wires in each layer increases with each layer. Flexible shaft REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Overrunning Clutches and Torque Limiters
The next section discusses overrunning Clutches and torque limiters REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Overrunning Clutches Wedging rollers Lawnmower clutch Molded sprags
Some simple, inexpensive overrunning clutches are shown. These transmit power in one direction only. The lawnmower clutch has a slide that will engage a tooth when driven in one direction but will slips past in the other direction. Wedging rollers can be used to transmit moderate torques while the molded sprags can only be used for light loads. The disengaging idler moves upward rather than driving the output when the input is rotated counterclockwise. Molded sprags Disengaging idler REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Torque Limiters Permanent magnets Arms hold rollers
Torque limiters are designed to limit the torque delivered to a load to avoid failure. Permanent magnets may be mounted in a clutch plate to transmit a limited torque. Spring loaded arms may be used to transmit torque between two shafts. Large torques cause the spring loaded arms to slip on the shafts. Permanent magnets Arms hold rollers REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Torque Limiters, cont. Flexible belt Cone clutch
A spring loaded cone clutch is designed to slip at large torques. The torque limit may be adjusted by tightening or loosening the nut. A flexible belt wrapped around four pins can be used to transmit very low torques. Flexible belt Cone clutch REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Torque Limiters, cont. Shear pin
Shear pins are used to transmit but limit torque on many machines including hay balers. Shear pin REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Fluid Pumps Flexible vanes Rameli pump
There are a number of different types of positive displacement pumps, a few of which are presented here. The Rameli pump uses eccentric rotation of two vanes. The vanes are spring loaded in order to maintain contact with the pump housing during rotation. Another design uses flexible vanes on an eccentric rotor. Flexible vanes Rameli pump REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Fluid Pumps, cont. Rotary compressor Eccentric disk
An eccentric disk can also be used to pump fluid. The inlet and outlet side are separated by a spring loaded gland. The rotary compressor also uses an eccentric rotor to provide pumping action. In this case the rotor is encased in an oscillating ring. A link is used to separate the inlet and outlet sides of the pump. Rotary compressor Eccentric disk REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Fluid Pumps, cont. Vane pump Roots compressor
The roots compressor or roots blower has gears external to the pump housing that ensure constant contact between the impellers. The fluid is forced around the outside of the housing by the impellers. The roots blower is often used on automotive superchargers. The vane pump uses an oscillating vane as a piston to expel fluid from the pump housing. The vane also has a one-way valve so that on the return portion of the stroke, the fluid moves from the inlet side to the outlet side of the vane. Vane pump Roots compressor REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Fluid Pumps, cont. Rotating cylinder block Rotary reciprocating pump
The rotating cylinder pump uses an eccentrically mounted block such that the pistons move relative to the block during rotation. The pistons are drawn into the block on the inlet side to draw fluid into the cylinders. The piston and fluid are forced out of the cylinders on the outlet side of the pump. The reciprocating rotary pump works similar to the vane pump. The difference is that both sides of the vane are used for both intake and outlet. Four one way valves are used to ensure fluid flow in one direction and therefore pumping action. Rotating cylinder block Rotary reciprocating pump REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

Credits This module is intended as a supplement to design classes in mechanical engineering. It was developed at The Ohio State University under the NSF sponsored Gateway Coalition (grant EEC ). Contributing members include: Gary Kinzel …………………………………….. Project supervisor Gary Kinzel…..…………………...……………...Primary author Matt Detrick ……………………..……….…….. Module revision Based on Mechanisms and Mechanical Devices, by N. Chironis and N. Sclater, Mcgraw-Hill, Inc. New York, 1996. REF: Mechanisms and Mechanical Devices Sourcebook, N. Chironis, N. Sclater, McGraw-Hill Inc., New York, 1996

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