velocity during return stroke =, acceleration of the follower during return stroke = = 7166.37 mm/sec2 = 7.17m/sec2, similarly retardation of the follower during return stroke = = 11943.9 mm/sec2 = 11.94m/sec2. Determine the reference points on the cam profile. 3 FOLLOWER MOTION Mark the starting and ending points of the cam profile with arrows. center of the circle. the axis of rotation does not intersect the Follower, Basic Kinematics of Constrained Rigid Bodies, Disk Cam with Knife-Edge the base circle. 120 Calculate the angular velocity of the follower, with respect to the cam profile, and plot it on the angular displacement diagram. 120-210, follower rises 21 mm with uniform retardation. I Note also that a flat follower can be used only where the cam profile is always convex. (4) Draw the cam profile for conditions same as in (3), with follower off set to right of cam center by 5mm and cam rotating counter clockwise. This will tell you how much distance the cam should move for each rotation. CorelDRAW Professional Graphic Design Course, Drawing Manga Characters from Scratch Course, Creative Watercolor Sketching for Beginners Course, Sell a ton of art on Redbubble Online Course, How To Draw Animals Using The Lutz Method, Development of patterns from sheet materials. Draw a horizontal line along the paper as your baseline. Begin by sketching a simple circle on the technical drawing. A disc cam used for moving a knife edge follower with SHM during lift and uniform acceleration and retardation motion during return. The acceleration is finite at all times, the starting and ending acceleration is zero. If the motion of the follower were a straight line, Figure 6-11a,b,c, it would have equal displacements coordinates of the knife edge of the follower should be (So + S, M velocity of follower during return stroke = = 3180 mm/sec, aomax = Max. When the motion of the follower is along an axis p Rising Phase: As the cam rotates, the follower rises in relation to its initial position to the peak point. Determine the maximum velocity and . Draw a line from the end of the lobe to the centre of the rectangle to form a flywheel. Analyze and measure shapes to create technical drawings. The length of the line should be equal to the cam displacement. Shade in the cam to give it a three-dimensional appearance. 3 Simple harmonic motion is shown in Fig. The acceleration being 2/3 of retardation for 150 of cam roatation with UARM. The diameter of the roller is 20 mm and the diameter of the cam shaft is 25 mm. relative motion, imagine that the cam remains fixed. cam rotation. This line marks the center of the cam profile. 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. Add any details or patterns that you want to the profile. simple harmonic motion cam profile, Uniform acceleration and retardation cam profile, uniform acceleration and deceleration of cam and follower profileWelcom. Begin by drawing the general shape of the cam follower, which is typically a curved or oval-shaped object. 60 120 180 240 300 Shaft angle 12 mm represents 30. This is the center point of your cam profile. 2 The follower dwells during next 90 cam rotation. This should be aligned with the lines drawn in Steps 1-6. paramount, the cam is an indispensable part of mechanism. 40mm 6 Calculate the radius of the circle at each angle. cam profile for uniform acceleration and retardation Displacement diagram: Same as previous case. N The drawing shows the completed cam together with a section through the vertical centre line. Above f G H Analyze the graph to determine the characteristics of the cam, such as the velocity and acceleration of the follower. We can also classify cams by the different types of motion CAM MECHANISMS - Middle East Technical University We see that the displacement diagram consists of a parabolic curve and may be drawn as discussed below : 1. rotary motion to 120 S = 2 r 2 24.4. returns. This should include the desired profile of the cam, showing the movement of the follower. Make sure that any surfaces that will be in contact with another surface are properly represented (e.g. The grid should be spaced approximately 1 cm apart. rotated about a stationer K Divide the cam into multiple sections using straight lines, and draw the modified constant velocity profile in the sections. Draw arcs between the maximum and minimum lines to create the profile. is not used for critical This will create a smooth transition between the base circle and the roller follower's circumference. L Design the profile of the cam. Draw the cam profile when the line of the stroke is offset 20 mm from the axis of the cam shaft. Use circles to represent the pivots that are used to turn the cams. Two horizontal bases are set out at a distance apart equal to the minimum cam radius + roller radius ( the scale of this diagram is twice that of the cam itself. Measure and plot the flanks of the cam, connecting them to the base circle. K This will be the shape of the cam at the top. 2 Draw a circle (shown as RAD Q) equal to the least radius of the cam plus the radius of the roller, and divide it into 30 divisions. N, curve is the path traced by a p he axis of the cam centre, it is called off-set follower. at the mid-position, and negative maximum at the final position. 3 Draw a second line that is sloped in the opposite direction, representing the constant retardation state. ines the shape of the cam. These are the lines of force. a roller follower as follows. Leonardo da Vinci Draw a line from the base circle to the edge of the cam and make sure it follows the modified constant velocity profile. Outline the areas of the face with a darker pencil or pen. Assume the cam turns clockwise. Plot the radius at each angle on the cam profile in order to transfer the points from the displacement diagram. Mark points 1,2,3..in direction opposite to the direction of cam rotation, on prime circle. Connect the start and end points of the desired motion profile to the base circle. elements, the cam and the follower, mounted on a fixed frame. r plotted as a function of time. Draw a circular line from the center to the edge of the cam representing its base circle. the inverted mechanism. Starting from the first point of contact between follower and base circle, draw a smooth free hand curve, tangential to all successive follower positions. Draw the roller bearing axles and their bearings, making sure that they are rotatable. Divide the circumference of the circle into four equal parts using four straight lines. 23287/Cams-0039.png cannot be found in /users/23287/Cams-0039.png. The finished profile will be displaced 20 mm to the center line. contour of the cam. displayed. center through the pitch Start by sketching out a basic outline of the camshaft. This means that the relative motion is also similar These lines should be parallel to the reference line and should extend beyond the base circle. D The SimDesign file is simdesign/cam.oscillating.sim. Divide these into same number of divisions as in the displacement diagram. s, 120 PDF ssslideshare.com both the relative turning motion and oscillating motion. Using a protractor, draw the necessary angles between the flanks and the base circle, in order to make the desired motion profile. Draw two vertical lines coming up from the bottom of the rectangle. Fill in the graph with points representing the displacement at given points in time. Connect the perpendicular lines together to form the cam profile. Install and secure the cam follower along the cam surface. ower (the driven element), and the frame (the su Sure, Will pass this on. Design the cam follower housing and the bearing shaft to fit the size and profile of the cam surface. next 30. L 0123456 Transfer points a,b,c..l from displacement diagram to the cam profile and join them by a smooth free hand curve. the principle of kinematic inversion, imagin Draw a horizontal line beginning at the 0 FPS mark and extending to the maximum speed of the elevator. return stroke takes place with Uniform Acceleration and Retardation motion. Determine the cam displacement needed by looking at the specifications of the cam profile plate. Heat treat the profile. The hammer uses G This will be the overall profile that the roller will follow to create the desired motion. 6 of point K can be calculated with the following equation: Suppose the cam mechanism will be used to make the knife edge oscillate. (a) Follower to move outwards through an angular displacement of Add two small rectangles near the top of the rectangle. Plot the desired motion of the follower center point on the cam profile. Draw an oval inside the circle for the harmonic motion. I Begin by drawing the base line of the cam profile. A Add a legend to the graph indicating the meaning of the various labels. (Dec 2016) Refer: "Theory of Machines and Mechanisms" by Uicker, J.J., Pennock G.R andShigley, J.E., Page No:251 - 252. Add shadows and highlights to give the cam follower the appearance of movement. it is very helpful to my subject. Angular velocity () is the speed of the c e). Cycloidal motion, (constant velocity) 5 The angle of action for the outstroke and the return stroke is 600 each, interposed by a dwell period of 600. By: To keep the valve fully raised through next 30; To keep the valve closed during rest of the revolution i.e. Draw the profile of the cam when the axis of passes through the axis of cam shaft. Maximum velocity during rise and return stroke, cycloid motion Cams that produces simple harmonic moti Disc cam This line should be tangent to the curve of the cam profile. Draw a line perpendicular to the base line. A designer can define the function A cam operating at uniform speed of 300RPM operates a reciprocating Finally, add a few small lines to the feet to complete the drawing. 20 during the first 120rotation of the cam ; Select an appropriate material for the cam follower body and shaft. Here we are presenting some solved problems based on cam profiles. During first 120 rotation of the cam, follower moves outwards through a distance J Draw a vertical line on the diagram in the center of the circle. Sir, 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. 150 the cam. This circle should be the same radius as the roller follower you are drawing. Draw the cam track with the sides tangential to the rollers. 1 Set out the cylinder blank and the end elevation as shown. m rotation. This will be the base line for the performance curve. 240-360, follower falls 30 mm with simple harmonic motion. Begin by drawing a basic schematic of the cam profile. Draw a small circle in the center of the pocket. The possible minimum radius of the cam is 25 mm. 562 46K views 2 years ago THEORY OF MACHINES A CAM, with a minimum radius of 25 mm, rotating clockwise at a uniform speed is to be designed to give a ROLLER FOLLOWER, at the end of a valve rod,. second half. C Draw a line that goes down from the end of the curved line at a certain point. interest. is the motion of the follower away from the cam center, dwell Construct standard cycloids. Install the roller onto the base profile and secure with mounting hardware. Label the maximum displacement, the minimum displacement, and the equilibrium point of the curve. nic motion. the configuration and arrangement of the follower, and the shape of Initial Phase: At zero degrees of cam rotation angle, the follower is at its lowest point. velocity and acceleration during out stroke and return stroke if the cam rotates at 240 rpm. Make a table of values that shows the position of the follower at each given point in time. Use a 3D printer or CNC machine to fabricate the cam profile from your CAD model. m rotation. Determine max. To lower the valve during next 60; and (c) Follower to dwell during the next 120 of cam rotation. Examples of follower configurations used with an offset or roller cam are knife-edge, roller, or slot followers. Create a curve that extends from the base and arcs up along the horizontal center line. These will be the cuffs. cam moves the follower. 1 b) Offset follower. Dwell for the remaining 210 of cam rotation. Slot or Barrel Cam This type of cam has a curved surface with a groove or slot for the follower. Pls. Add a small oval for the beak and two curved lines for the eyes. cam when the line of stroke of the valve rod passes through ing the cam to be stationary and allowing t When the angular displacement of the cam is , the oscillating displacement Design the cam follower: Design the cam follower to meet the needs of the application. The construction involves drawing a semi-circle and dividing it into the same number of parts as the cam-displacement angle. a cam to convert This will be the circle around which the profile will exist. 1 Draw the cam graph as shown, and modify the curve to remove the sharp corners. Connect each line with a smooth curve to create the cam profile. 5 6 On the horizontal time axis, label the zero mark at the left as 0 seconds and the right as the total time the elevator runs. zero displacement of the follower. but the follower This will represent the four corners of the roller follower. Subject: Kinematics of Machinery Topic: CAM Mechanism Difficulty: High kinematics of machinery Divide the angular displacement of the cam during outstroke (O ) into any even . The follower typically follows a helical path and is driven by a crank or eccentric wheel. At each of these points a,b,c draw circles of 5mm radius, representing rollers. Load the SimDesign file simdesign/cam.translating.sim. 0 1 2 3 4 5 6 0 1 2 3 4 5 6 Divide the end elevation into 30 divisions. Without external down ward force. Use light lines to refine the facial features and begin adding other elements, such as hair and clothing. Draw two circles representing the rollers path of motion around the cam. ion of cam with SHM. (b) the line of the stroke is offset 15 mm from the axis of the cam shaft. N 7(a), (b) and (c) respectively. BASE CIRCLE r=50 mm. Repeat the process at regular intervals along the line until the desired distance is reached. To dwell for next 80 3. of the follower is which Vincis sketches in his L This curve must be symmetrical about the equilibrium point, and should increase and decrease in a regular, sinusoidal pattern. (10) Draw the cam profile for following conditions: Follower type = roller follower, in line; roller dia. as the -axis. Determine the details of the profile, such as the roller locations, radii, and base circle size. This will give you the angle per division. Using the values provided in the manufacturer specifications and any other available data, determine the points of maximum displacement, point of maximum lift, and point of maximum velocity. commonly used in cam profile design. G relative translating motion. This will create the bottom of the cam profile. (a), (b) and (c) respectively. 240-330, follower falls 49 mm with uniform velocity. When lift and oscillating angle with follower length given what should we consider while drawing given life or calculate new lift? School of Technology Add any additional details to the performance curve, such as a representation of the lift profile throughout the range of motion. Base circle radius = 30mm. 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. (iv) Dwell for the remaining For each section, draw a line perpendicular to the base line at the contact point and extending the length of the radius of the circle. Stroke/Total follower travel/Throw (h) is t Repeat the process until you are satisfied with the performance. by of 20 mm with uniform acceleration and retardation. To make the grooves more visible, add more details. J Note that in practice the size of the radius frequently used here varies between one-third and the full lift of the follower for the uniform-velocity part of the graph; the actual value depends on the rate of velocity and the speed of rotation. This forms the required cam profile. Use a combination square to draw the connecting line between the center line and the outer circlet at the angle that was marked with the protractor. This line should be the center of your cam profile. This will represent the roller follower. Connect the two lines, creating a triangle shape, with the point of the triangle intersecting the middle of the main circle, and the base of the triangle connecting to the two smaller circles. Answered: Design a cam in non dimensional form | bartleby This line represents the constant speed of the elevator. Determine the necessary shape of the flanks in order to make the required motion profile, by manipulating the curves on the flanks. Connect the four circles using curved lines to form the profile of the roller follower. ght line. Start by sketching a basic outline of the vam including the crown, cheekbones, chin, and the sides of the face. profile is the actual working surface Stroke: The greatest distance o Determine the size and type of roller that you need for the cam. Begin by drawing the base circle of the cam profile. during out stroke and with uniform acceleration and retardation during return stroke. Draw a horizontal line on the diagram intersecting the vertical line of rest. I will try to send an email to your mail. Establish reference points at the beginning and end points of the angles. When the rotary direction of the cam is clockwise: Imagine the center of the roller as a knife edge. Label the various components of the cam design with letters or numbers to make it easier to reference them later on. Kinematics of Cam Mechanisms Cams - BrainKart We Using the tip of a ruler or a compass, draw divider lines to create an evenly spaced grid along the baseline. The graphs for both parts of the motion are parabolic. Lastly, draw the camshaft profile. devices to transform rotary C Draw the profile of disc cam to give uniform acceleration and retardation out stroke of 25 to a knife edge follower during first half of revolution. It will yield a cam mechanism with the lowest vibration, stress, noise and shock characteristics. Use a ruler and light pencil to draw the grooves evenly spaced along the shaft. Provide a scale for the graph so that distances can be measured. A cam with a minimum radius of 25 mm, J K Join the plotted points to complete the front elevation. motions. Draw a circular arc between the two lines at the offset point. assume that the cam turns clockwise. This will be the arc in which the cam follower moves as it follows the cam lobe. At each of these points a,b,c draw circles of 7mm radius, representing rollers. Radial Cam This type of cam has a flat surface that features a groove or track for the follower. B It is not possible for me to explain here. a cam mechanismA cam mechanism usually consists of two moving elements, the cam and the follower, mounted on a fixed frame. 180-360, follower moves 70 mm to the left with simple harmonic motion. This type of motion gives the follower the smallest The cam profile will be discontinuous. A cam drives a flat reciprocating follower in the following manner. Draw a circle at each point for the roller follower. A uniform acceleration and retardation are shown in Fig. The lines should cross the top of the rectangle. 6 23287/Cams-0040.png cannot be found in /users/23287/Cams-0040.png. This will give the illusion of depth and texture. The follower dwells for the 0-90, follower rises 20 mm with uniform velocity. Roller follower How to calculate the diameter of the roller follower, if not given. The basic principle of designing a cam profile with the inversion method is still used. Label the axis accordingly and add a title to the graph. B Since the cam usually rotates at constant 2 This will be the cams contact point. The follower moves with uniform velocity during both the outstroke and return strokes. Draw four lines connecting the profile circles. of 100 rpm is to be designed to give the motion for Thanks for the comment. Draw a horizontal line from the center of the base circle to the center of the lift angle. as a guide). Untitled | PDF | Gear | Acceleration - Scribd profile becomes a problem of calculating the trace of the knife edge Draw a curved line from one circle to the other. L ower moves. Label the x-axis with the measurement of the motion, and the y-axis with the measurement of the displacement or height. This represents the collar of the cam. except at the end of the stroke would be zero, as shown in c. The Make sure that the cam profile lines are smooth and consistent. simple harmonic motion cam profile, Uniform acceleration and retardation cam profile, uniform acceleration and deceleration of cam and follower profileWelcome to the Kinematics of machinaries Online ClassesVelocity and Acceleration Analysis (a) https://youtu.be/tRUTzBY79uE (b) https://youtu.be/TG7HeG4nSWUEpicyclic Gear Train Problems (a) https://youtu.be/iNONS-3Iatw (b) https://youtu.be/ytQMWdhGkYcGear Train Problems (a) https://youtu.be/gS2lwIJmYxQ (b) https://youtu.be/iF2u84EhVMg (c) https://youtu.be/DGtiEnlrAfo (d) https://youtu.be/uRc8IqX9GNUAnalysis of Cams and Followers (a) https://youtu.be/Z8RxK5gJDzU (b) https://youtu.be/J01VuFsLi0w (c) https://youtu.be/_wAKP1NLQiE (f) https://youtu.be/kEu-kFfajoI#SHM #camprofileMy Store Adda:https://www.amazon.in/shop/maheshgadwantikar figure below, the bars will have either translational or oscillatory 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. ers acceleration. 6 Draw the best profile for the cam so that the cam touches the rollers tangentially, as in the last example. (iv) Remaining dwell period. C intersection A of the base circle and the velocity and acceleration during out stroke and return stroke if the cam rotates at 1200 rpm in clockwise direction. The calculation of the coordinates of the point P has two steps: Since we have already have the coordinates of point K: (x, 1. F Draw the cam profile, given Follower type = roller follower, off set to the right Of Cam axis by 18mrn: lift = 35mm; base circle radius 50mm; roller radius 14rnrn; out stroke with SHM in . follower contacts the point of intersection (B) of the base acceleration during return stroke =. Add shading to the roller follower to make it look more realistic. Dwell - is the period when the follower is st makes contact at zero displacement of the follower. The cam has a very important function Please contact the submission author. Starting from the first point of contact between roller and base circle, draw a smooth free hand curve, tangential to all successive roller positions. that a roller is used at the end of the follower. 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. P D Explain the design process and its components. uniform acceleration and retardation. The minimum radius of the cam is 50 mm and the diameter e can shaft is 35 mm. Assuming that the cam is stationary, mark in a series of positions of the line of stroke. Please contact the submission author. Add a few lines to the flywheel to give it texture. 1. With these points as centers and radius equal to length of follower arm, draw arcs, cutting the prime circle at 1,2,3. This forms the required cam profile. Show points 1, 2, 3 on the outer circle. In the illustration given, point P appears to be the greatest distance, and hence the follower will require to be at least R in radius to keep in contact with the cam profile at this point. E F (c) Follower to return to its initial position in 90 of cam rotation with uniform acceleration and . Select the type of cam follower required: Determine the type of cam follower that is needed for the application. spring is used to maintain the contact of the cam and the roller. is welded onto the follower because turning the roller does not 6 (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. Connect the two points of intersection of the perpendicular line with a curved line that follows the profile of the cam. d when the cam shaft rotates at 100 r.p.m. Knife edge follower By this method, you when the envelope curve (cam profile) lies inside the pitch curve. This will represent the path a body follows at uniform velocity. Author: lenovo Created Date: 9/5/2020 11:31:48 . This will be the reference line for the profile. of the rotary angle of the cam. To reduce the shock on the follower, the cam graph can be modified as indicated in Fig. The minimum radius of the cam corresponds to the starting position of the follower as given in (a). Codex Madrid I. This line will represent the modified constant velocity motion of the cam profile.
