The possible Different types of cams are presented, how to draw profile that is also discussed. Draw the cam profile for following conditions: Follower type = roller follower, in-line; lift = 25mm; base circle radius = 20mm; roller radius = 5mm; out stroke with UARM, for 1200 cam. M Draw the profile of a cam with oscillating roller follower for the following motion : (a) Follower to move outwards through an angular displacement of 20 during 120 of cam rotation. devices are versatile, and almost any arbitrarily-specified motion can It should look like a series of peaks and troughs. commonly used in cam profile design. Start by drawing the outline of the camshaft. urve is continuous. Label the x-axis with the measurement of the motion, and the y-axis with the measurement of the displacement or height. Connect the two points of intersection of the perpendicular line with a curved line that follows the profile of the cam. 30 mm diameter camshaft. Mark the camshaft angles in the anticlockwise direction. At the beginning of motion, the knife edge of the Verify and adjust the cam profile: Analyze the changes you have made to the cam profile. 2 4. a flat reciprocating follower in the following manner : Draw a third curved line connecting the two lines in the middle. Please contact the submission author. 9. velocity and acceleration during out stroke and return stroke if the cam rotates at 240 rpm. Assume the cam turns clockwise. (ii) Dwell for next 300 profile to drive an oscillating roller follower to the specifications Fill in the graph with points representing the displacement at given points in time. We see that the displacement diagram consists of a parabolic curve and may be drawn as discussed below : 1. This is the diagram that shows how the camshaft interacts with the tappets. Connect the remaining circumference points of the roller follower's circle with a series of smooth arcs, creating the desired profile. We see that the displacement diagram consists of a parabolic curve . Record the data. These will be the pockets. +0. F Determine the type of cam follower needed (such as ball or roller) and size the bearing to the application requirements. Cam speed = 240rpm. fig. B TRACE POINT, curve : The path When you move the book smoothly upward, what happens to This vertical line will represent the peak of the cam profile. At this moment, the L Roller follower 2 Uniform acceleration and retardation motion is shown in Fig. Finally, draw a line from the base circle to the edge of the cam that represents the reference line. Draw a center line through the center of the roller follower. P A cam with a minimum radius of 25 mm, The uniform-retardation parabola is constructed in a similar manner, but in the reverse position. Draw a vertical line extending from the base line to the parallel line. on to the follower are called eccentric cam If speed is given is counter clockwise than how to draw profile of cam, sir its fantastic work, only one help sir may i get copy of work to my mailid. variety. Divide these into same number of divisions as in the displacement diagram. M Next, sketch out the grooves that will run along the camshaft. r = S/ 2 23287/Cams-0042.png cannot be found in /users/23287/Cams-0042.png. Draw an oval inside the circle for the harmonic motion. In cases where the cam can be fitted back to front, the direction or rotation should also be clearly marked. acceleration during outstroke =, armax = Max. Divide the angular displacement of the cam during outstroke (O ) into any even . 4 the bearing raceway). Draw a circle below the line to represent the cam, and another circle below that to represent the follower. Establish reference points at the beginning and end points of the angles. Design the cam follower: Design the cam follower to meet the needs of the application. Point follower. To raise the valve through 50 mm during 120 rotation of the cam ; 4 Plot the Y ordinates from the cam graph along each of the radial lines in turn, measuring from the base circle. (c) Follower to dwell during the next 120 of cam rotation. Draw a series of parallel lines to represent each of the different cams that make up the cam design. Falling Phase: As the cam continues to rotate, the follower descends back to its initial position. Draw arcs between the maximum and minimum lines to create the profile. Rising Phase: As the cam rotates, the follower rises in relation to its initial position to the peak point. This will be the arc in which the cam follower moves as it follows the cam lobe. 6 Do this by slowly advancing the camshaft until the peak torque is found, then slowly reducing the speed to return the engine to idle. Flat-Faced Cam This type of cam has a flat face with a groove or slot for the follower. Notice Begin by drawing a straight line segment with arrows at both ends to represent the rotation of the cam. Finally, add labels to the diagram that indicate the rotation of the camshaft. between them is a combination of a relative turning motion and a This will be the belt. relative translating motion. Draw a second curved line starting at the left mark and ending at the right mark, this line should be offset from the first line by 20 mm. Draw the profile of the cam when the line of The tangents represent the face of the flat follower in each position. EF having a curved outline or a curved groove, Figure 6-12 is a skeleton diagram of a disk cam with a knife-edge translates when the cam turns. were found in Leonardo da Record the position of the follower over time. Connect the end of the cam profile to the center line with a curved line. CD high acceleration at N Draw a vertical line from the center of the base circle to the center of the lift angle. Helpp! Alternatively, a timing hole can be drilled on the plate, or a mark may be engraved on the plate surface. Draw a line from the collar down the center of the rectangle. is also similar Shade the areas of the cam that represent the modified constant velocity motion. in the reverse direction through an angle of . e with simple harmonic motion. The follower dwells for the Radius of cycloid generating circle = = 8.4 mm, Angular velocity of cam = = 62.86 rad/sec, vomax = Max. Draw a horizontal line on the diagram intersecting the vertical line of rest. AB When finished using the region, unmap the memory using the munmap system call. Min radius, 120 To return to its starting position during next Draw a line that connects the end of the curved line with the base line. 4. G nic motion. Gravity constraint Then the principle of kinematic . C Use of templates and stencils (for simple profile designs). Question: Example Problem 3 (Uniform Acceleration and Retardation Follower) A cam, with a minimum radius of 50 mm, rotating clockwise at a uniform speed, is required to give a knife edge follower the motion as described below: 1. both the relative turning motion and oscillating motion. The length of the line should be equal to the cam displacement. Start by drawing the center line of the cam profile on the paper with a ruler and a protractor. The calculation of the coordinates of the point P has two steps: Since we have already have the coordinates of point K: (x, Begin by drawing a vertical line on the paper. I Use a ruler and light pencil to draw the grooves evenly spaced along the shaft. This video explains how to draw displacement diagram in case of follower motion with S.H.M. Start by drawing a tall and narrow rectangle with a curved top. The angle of action for the outstroke and the return stroke is 600 each, interposed by a dwell period of 600. Draw a circular arc between the two lines at the offset point. Draw the lobes of the camshaft. Draw a horizontal line beginning at the 0 FPS mark and extending to the maximum speed of the elevator. Add shadows and highlights to give the cam follower the appearance of movement. s, 120 Then draw a curved line that goes up from the base line at a certain point. This will form the base for the cam. Draw the maximum and minimum lines for the profile. Plot the position of the follower on a coordinate plane at each point in time. the pencil? velocity and acceleration during outstroke and return stroke, if the cam rotates at 600 rpm. 4 5 0 1 2 3 4 5 6 Connect the ends of the two curved lines with a final line, completing the cam profile. 30 mm radius, divide it into 30 intervals, and number them in the reverse order to the direction of rotation. Cams are classified according to the direction of displacement of the follower with respect to the axis or oscillation of the cam. 1 Uniform velocity This motion is used where the follower is required to rise or fall at a constant speed, and is often referred to as straight-line motion. the axis of rotation does not intersect the Best wishes. Follow Steps 2-5 to draw the cam profile onto the technical drawing. This type of motion is not desirable for high speeds. 23287/Cams-0002.png cannot be found in /users/23287/Cams-0002.png. oscillating follower, Radial or disc cam profile of the cam. Determine the size and type of roller that you need for the cam. To make the grooves more visible, add more details. Label the x-axis for the angular displacement of the follower in degrees and the y-axis for the corresponding displacement of the follower. Mark the offset point in relation to the base circle, and draw straight lines connecting the offset point to each circumference point of the roller follower. as a guide). These are the lines of force. y), we can express the coordinates of point P as, Disk Cam with Knife-Edge Translating Follower, Disk Cam with Oscillating Knife-Edge The follower dwells during next 30 of ca Simple Harmonic Motion (SHM): the base circle. figure below, the bars will have either translational or oscillatory center through the pitch This will be the base line for the performance curve. (b) Follower to return to its initial position during next 120 rotation of Starting from the first point of contact between follower and base circle, draw a smooth free hand curve, tangential to all successive follower positions. 1 0 Mark the starting and ending points of the cam profile with arrows. Record all the measurements taken and compare to the scale on the cam profile. Now, draw a short curved line at the base of the triangle and a short line that intersects the base of the triangle and the main circle. Someone will definitely do. The lines should cross the top of the rectangle. Draw a straight horizontal line beginning at the right side of the time axis and extending back to the maximum speed line. 6 This marks the beginning of the cam profile. J K This circle should intersect all of the lines that were previously drawn. This should include the base circle, the lift and dwell angles. velocity of follower during return stroke = = 3180 mm/sec, aomax = Max. Since the cam usually rotates at constant Design the cam follower for the specific application, such as type of motion, load, speed and environment. Draw a small line perpendicular to the first line near one of its ends. EF N follower moves along the fixed cam profile in the inverted mechanism. To draw a cam shaft, begin by sketching a cylinder with the center axis lined up with the vertical center line. 60 Secure the bearing in place with a nut and screw. To complete the image of the falling cam follower, draw in a few straight lines to indicate the angle of the cam follower as it drops. smooth out in the Add two circles on either side of the rectangle. The sections should represent the different positions a camshaft will take during rotation. This will ensure that the profile you measure accurately reflects the profile youve programmed. Interpret and understand drawing conventions. The graph should now represent the simple harmonic motion of n4 draughting. Fig.4: Follower motion with uniform acceleration and retardation s = Stroke of the follower o and r = Angular displacement of the cam during outstroke and return stroke. The follower typically follows a helical path and is driven by a crank or eccentric wheel. Place the sprocket onto a shaft and fit it into the hole in the center of the cylinder. C Return stroke during next 60 of cam rotation, and g next 30 of cam rotation. return stroke takes place with Uniform Acceleration and Retardation motion. Draw a curved line from the beginning of the cam profile to the end of the first line. BASIC PRINCIPLE, to give the following motion to a knife-edged follower : is the motion of the follower away from the cam center, dwell Draw a horizontal line intersecting the vertical line at the equilibrium point, which is the point of no displacement. Draw the line of the cam followers movement. is the motion during which the follower is at rest; and return Now use a scriber to trace around the outer circles and the line connecting the center line and the outer circles. Least radius of cam, 35. Start by drawing a vertical line representing the displacement (x) of the mass on the spring. Finally, draw a circle that represents the apex of the cam profile. (12) A push rod of valve of an IC engine ascends with UARM, along a path inclined to the vertical at 600. Note that, although the roller shown is parallel, tapered rollers are often used, since points on the outside of the cylinder travel at a greater linear speed than points at the bottom of the groove, and a parallel roller follower tends to skid. Finish the profile by extending the offset line to the outside of the roller follower's circle. The follower typically follows a circular or an elliptical track and is rotated by a crank or an eccentric wheel. This will help to better represent the grooves on the camshaft. A rotary motion to motions. 330-360, dwell period. 120 180 240 12 mm represents 30 camshaft angle. Draw additional curved lines to indicate the feathers of the wings. This will be the angle between the base circle radius and the circle that intersects the follower center point at the desired speed of travel. Draw the time axis, extending from left to right starting from the equilibrium point. Radial lines are drawn from the start position to each of the follower division lines, and the parabola is obtained by drawing a line through successive intersections. This is done by using the cam milling machine to cut the profile into the work piece. systems because the I uniform acceleration and retardation and simple harmonic motion outputs; output characteristics of eccentric circular cams, circular arc cams and cams with circular arc and . Add a small oval for the beak and two curved lines for the eyes. Begin by drawing a line representing the rotation of the cam. 1 Begin at the top of the cam and use a darker shade of bluish gray as you shade downwards, becoming lighter as you reach the bottom of the cam. E according to the specific requirements in the design. In order to draw the cam profile for a radial cam, first of all the displacement diagram for the given motion of the follower is drawn. The translational or rotational displacement of the follower is a function Begin by sketching the basic profile of your cam design. P, O book an inclined plane and use the pencil as a slider (use your hand Poonam Savsani The diameter of the roller is 20 mm and the diameter of the cam shaft is 25 mm. in relation to time or the rotary angle of the Finalize the cam profile: Carefully review the final cam profile and make any necessary changes to ensure that it provides the optimal performance and efficiency. The curve should have a gradual slope up and then back down at the end. Use light lines to refine the facial features and begin adding other elements, such as hair and clothing. If you try to calculate the degrees of L BASE CIRCLE r=50 mm. Utilize freehand sketching and orthographic projections. Finally, add any additional details and lines as desired to finish your drawing. To reduce the shock on the follower, the cam graph can be modified as indicated in Fig. is not used for critical Using a protractor, draw the necessary angles between the flanks and the base circle, in order to make the desired motion profile. The follower displacement diagram determ Begin by drawing the profile of the cam. Stroke of the follower is 30mm, minimum radius of the cam is 30 mm. Dwell - is the period when the follower is st Determine the base circle radius based on the desired follower radius and center point radius. curve is not directly generated by inversion. Cams; their profiles and the velocity and acceleration of their associated followers. 0123456 Note that the projection lines for this operation do not come from the circles in the plan, except at each end of the track. Label the axes with the time units and displacement units, respectively. Last Updated: Saturday, December 6, 2014, Kinematics of Machines Tutorials : Classification of cams and followers, STRAIGHT LINE MECHANISMS | Kinematics of Machines Tutorials, STEERING MECHANISMS | Kinematics of Machines Tutorials, Intermittent motion mechanisms and Pantograph | Kinematics of Machines Tutorials, Terminology for Spur Gears | Kinematics of Machines Tutorials, Previous Years GATE Questions on Engineering Materials 2002-2011, Previous Years GATE Questions on Joining Process 2005-2011, Previous Years GATE Questions on Joining Process 2001-2004, Previous Years GATE Questions on Forming Process 2007-2013, Previous Years GATE Questions on Forming Process 2004-2006. 90-150, follower rises 30 mm with simple harmonic motion. Measure the displacement at each point on the diagram. follower contacts the point of intersection (B) of the base 5 These are the points around which the profile will be measured. Begin by drawing a rough outline of the cam shape. periphery of the Set up the EDG (Engine Diagnostic Gauge): Make sure the gauge is properly connected to the camshaft. This will be the cuff edges. In radial cams, the follower reciprocates or oscillates 240-360, fall 64 mm with uniform velocity. draws the profile of the cam. cam. Vincis sketches in his This should be a long, cylindrical shape with a cylinder at the end. Draw two curved lines coming down from the collar. Draw two smaller circles inside the larger circles. No acceleration discontinuities, therefore it 60 From a knowledge of the displacements in each of these positions and allowing for the type of follower to be used, it is possible to draw the required profile of the cam (See Examples 2 and 3). 9. through 40 mm in of revolution, keep it fully raised through 1/10 th 1 th 4 revolution and to lower it with uniform acceleration and retardation in 1/6 th revolution. Begin by drawing a horizontal line to represent the initial position of the cam follower. Draw the profile of the cam when the axis of passes through the axis of cam shaft. Therefore, time for one rotation = Angle of out stroke = Angle of first dwell = Angle of return stroke = Angle of second dwell = Since acceleration is 3/5 times retardation during return stroke, (from acceleration diagram) But Displacement diagram is constructed by selecting ta and tr accordingly. Codex Madrid I. 0123456 (a) Follower to move outwards through an angular displacement of curve, The angle between the direction of the Your cam shaft drawing is now complete. speed N P. outstroke and return stroke. This is done to ensure that the cam profile is strong and durable. School of Technology The minimum radius of the cam is 25 mm. translating follower. 60 B Stroke/Total follower travel/Throw (h) is t except at the end of the stroke would be zero, as shown in c. The Machine the cam with the desired features and tolerances. K The stroke of the follower is 20mm. G H This should be aligned with the lines drawn in Steps 1-6. 20 mm diameter roller follower set 20 mm to the right of the centre line for the camshaft. interest. Calculate the torque of the follower, with respect to the cam profile, and plot it on the angular displacement diagram. These circles should be the same radius as the roller follower and should be placed in the bottom left and top right corners of the larger circle. The axis of the roller and the cam fall on the same vertical line. A The minimum radius of the cam is 25 mm. Draw a horizontal line through the center of the circle. 3 Simple harmonic motion is shown in Fig. uniform acceleration and retardation. Plot the radius at each angle on the cam profile in order to transfer the points from the displacement diagram. It is the surface in conta Place the gage to measure the cam profile. Divide the end elevation into 30 divisions. The spring must be properly designed to maintain contact. Include the shaft size, length, and diameter. 0-180, follower rises 30 mm with simple harmonic motion. 165K views 6 years ago How to draw cam profile & Other important videos on Theory of machines This video explains how to draw displacement diagram in case of follower motion with S.H.M. 5 D Create a chart using two vertical axes: one measuring the elevator speed in feet/second (FPS) and the other measuring the time in seconds. (a), (b) and (c) respectively. Starting from the first point of contact between roller and base circle, draw a smooth free hand curve, tangential to all successive roller positions. L M N he profile of the cam. Draw t Transfer points a,b,c..l from displacement diagram. 4 (9) Draw the cam profile for following conditions: Follower type = flat faced follower, in line; follower rises by 20mm with SHM in 1200 of cam rotation, dwells for 300 of cam rotation; returns with SHM in 1200 of cam rotation and dwells during the remaining period. Select an appropriate material for the cam follower body and shaft. Face cam, rotating clockwise. cam when the line of stroke of the valve rod passes through the principle of kinematic inversion, imagin follower through a roller 15 mm diameter. 60 30 60 next 90 of cam rotation. he axis of the cam centre, it is called off-set follower. into any other motions is often conveniently accomplished by means of Vector Art, Images, and Graphics Download. paramount, the cam is an indispensable part of mechanism. Start by drawing a base line. Label the axis accordingly and add a title to the graph. If the motion of the follower were a straight line, Figure 6-11a,b,c, it would have equal displacements a cam is required for an automated transfer mechanism. Translating cam Translating follower, to the shape of follower to define a knife-edge follower and a translating follower cam mechanism. H contour of the cam. Rise (b) Follower to dwell for 50 of cam rotation. Carefully measure the profile from the reference points, making sure to note the measurements in order to accurately reproduce the cam profile. C Draw a line representing the follower displacement, starting at the origin (x=0, y=0). FOLLOWER MOTION 1 to realize the displacement relationship between the rotation of the a) Radial follower Create an assembly drawing that includes the roller follower, any other components, and the assembly sequence. 2 To plot the cam, draw a 20 mm diameter circle to represent the bore for the camshaft, and another circle 30 mm radius to represent the base circle, or the least radius of the cam, i.e. Label the area of the graph where the displacement of the follower is above the origin as increasing and the area below the origin as decreasing. Depth of groove, 7 mm. Connect the new points of intersection with a curved line that follows the profile of the cam. OFFSET CIRCLE r=20 mm Mark the positions of the roller bearing axles. 4 During the next 90 cam rotation, the follower moves inward with SHM. 4 Finally, add some details such as a shadow and highlights to give it a three-dimensional look. Start by plotting the load on the horizontal axis and the displacement on the vertical axis. If the clutch is an old clutch, then uniform rate of wear assumption is more valid. Draw a horizontal line for the x-axis, representing the motion of the plate follower. Connect the lines with smooth curves to create the cam profile. This can be done by calculating the position of the follower for each angle, or by using a lookup table if available. returns. Draw a line from the centerline to the end of the offset line. am or the ratio of the angular displacemen it is very helpful to my subject. Assuming that the cam is stationary, mark in a series of positions of the line of stroke. Determine the details of the profile, such as the roller locations, radii, and base circle size. Draw two arms extending out from the body. To get the corresponding position of the knife edge of the follower in Connect the various parts of the cam design using arrows to show how they interact with one another. Uniform motion ( constant velocity) Trace the cam profile onto a sheet of stock. Connect the outer circles and the inner circles using two curved lines. he follower to rotate opposite to the directi The Cam Profile For A Given Motion Of The Follower If the required displacement of the follower is known for all angular positions of the cam, then graphical methods can be used to determine the necessary cam outline. Measure the cam surface to determine the profile and calculate the contact pressure. Place the compass on the line and draw a circle. s. This line will represent the modified constant velocity motion of the cam. These should be short and parallel to each other. Draw the cam profile and calculate the maximum values of velocity and acceleration when cam rotates at 10 rad/s. To keep the valve fully raised through next 30; or oscillates in a direction parallel to the cams The stroke of the follower is 30 mm and is completed in 0.02 second from rest to rest. We assume that the cam mechanism will be used Cycloidal Motion, the cycloid motion Mark points 1,2,3..in direction opposite to the direction of cam rotation, on prime circle. This line should start at one end of the rotation and end at the other. Mark the edges of the cam at the appropriate angles to designate each division. Start by drawing a long and thin rectangle in the middle of your paper. Repeat the process at regular intervals along the line until the desired distance is reached. is to be designed to give a roller follower, at the end of a valve rod, motion described be This is called a gravity constraint cam. G of 20 mm with simple hormonic motion. The least radius of the cam is 25 mm which rotates at 300 rpm. 2 (I) Outward during 1500 with UARM The graphs for both parts of the motion are parabolic. 2 a roller follower as follows. Start the outline at the center of the cam and draw outwards in a circular shape that is slightly uneven. Draw two vertical lines coming up from the bottom of the rectangle.
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