Although we checked the errors, but if you mark some error, let us known in the comment box. have transformed one motion into another motion by a very simple Shade the areas of the cam that represent the modified constant velocity motion. E Need to know the scheme of valuation of the cam .plz. Camshaft diameter, 20 mm. 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. of 20 mm with simple hormonic motion. 2 Draw the base circle as before. r angle through which the follow Label the axes with the time units and displacement units, respectively. 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. Connect the four circles using curved lines to form the profile of the roller follower. Final assembly and testing: Complete the final assembly of the cam follower and test it to ensure that it meets all of the design requirements. Explain the design process and its components. D
PDF Unit 60: Dynamics of Machines cylindrical cams, the follower reciprocates or oscillates in a direction parallel to the cams If they match, the cam profile has been successfully measured. Angle of rise / ascent / outstroke next 30. Determine max. as a guide). Show points 1, 2, 3 on the outer circle. Finally, add labels to the diagram that indicate the rotation of the camshaft. follower from a specific zero or rest position Without changing this feature of their (ii) Draw two arms extending out from the body. It is given that Least radius of the cam is 60 mm, Lift of the follower is 45 mm, Angle of ascent is 60 degrees, Angle of dwell between ascent and descent is 40 degrees, and Angle of descent is 75 0 Cam rotates at 300 rpm clockwise direction. Finally, draw a circle that represents the apex of the cam profile. are required to produce the accelerations. 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. M Maximum acceleration during outstroke and return stroke. Provide a scale for the graph so that distances can be measured. Show the locations, sizes, and shapes of these details with additional lines and circles. Transfer points a,b,c.. on to these arcs from displacement diagram. to another element called the follower . measures from its own initial position. \u0026 uniform acceleration \u0026 retardation. N 5 the inverted mechanism. Draw the displacement, the velocity and the Since the cam usually rotates at constant It should look like a series of peaks and troughs. 3 Draw radial lines 30 apart from the cam centre, and number them in the reverse direction to the cam rotation. If we have 60 outstroke and 90 return stroke then how can I divide both of them in 6 equal parts . 210, the follower is offset by 20 mm from the axis Ensure each division is accurately measured. turning and the relative translating. Draw a vertical line on the diagram in the center of the circle. This line should be sloped in one direction. This will represent the follower arm. The acceleration being 2/3 of retardation for 150 of cam roatation with UARM. Take a pencil and a book to do an experiment as shown above. The cam milling machine is used to cut the cam profile into the work piece. Begin by drawing a center line that intersects two circles. Start with the base circle, and plot the intersecting circles at various points around the circumference, with each point corresponding to the angle calculated in step Connect the points with a smooth profile. Use shading to bring out the facial features, such as the eyes and nose, by using lighter and darker tones. Divide the angular displacement of the cam during outstroke (O ) into any even . 120-210, follower rises 21 mm with uniform retardation. Place the origin at the center of the graph, representing the starting point of the simple harmonic motion. The displacement, velocity and acceleration patterns are shown in fig. ; base circle radius = 20mm; roller radius = 7mm; follower to rise through 400 during 900 of cam rotation with cycloidal motion; dwell for 300; return stroke with cycloidal motion during 1200 of cam rotation; dwell for the remaining period. Use arrows to indicate the directions of motion and the forces that act on the cams. 2345 Sketch the desired profile on graph paper with the desired start and end points. between them is a combination of a relative turning motion and a 5 From the base circle, mark lengths equal to the lengths of the Y ordinates from the graph, and at each position draw a 20 mm diameter circle for the roller follower. 3 L M N Start by sketching a basic outline of the vam including the crown, cheekbones, chin, and the sides of the face. Determine the maximum velocity and . A groove maintains positive action. Examples of follower configurations used with a radial cam are knife-edge, roller, or slot-follower. Connect the lines with smooth curves to create the cam profile. Cam is a very important topic in the kinematics of machines or theory of machines.
30 If you try to calculate the degrees of second half. 25 mm diameter camshaft. 2 The stroke of the follower is 20mm. Starting from the left of the grid, draw a line from the baseline going up, to the same displacement you determined in the previous step. This forms the profile of the cam. 6 To move outwards through 40 mm during 100 rotation of the cam 2. in the reverse direction through an angle of . 3. a half-return to a uniform velocity 4. a uniform velocity segment 5. a half-return back to rest (a) Plot the position y(in), velocity _y(in/s), and acceleration y(ft/s2) vs cam angle (DEG) for the complete motion. EF J Label the points and lines that represent specific times on the time axis. Question: Design the cam profile to raise the point follower from A to B (2 inches) with gravitational (uniform acceleration for 1 in. motion, gives a predetermined specified motion to another element To keep the valve closed during rest of the revolution i.e. m rotation. Connect the outer circles and the inner circles using two curved lines. nter, or spherical-faced center. Construct the profile using a cam milling machine. 0-90, follower rises 20 mm with uniform velocity. Draft technical drawings using the AutoCAD software. (6) Draw the cam profile for following conditions: Follower type = knife edged follower, in line; lift = 30mm; base circle radius = 20mm; out stroke with uniform velocity in 1200 of cam rotation; dwell for 600; return stroke with uniform velocity, during 900 of cam rotation; dwell for the remaining period. Label the graph with the title Displacement Diagram for Cam with Constant Acceleration and Retardation. b' Transfer points a,b,c..l from displacement diagram. translating follower cam mechanism). Finally, erase any unnecessary lines and the profile is complete. Draw arrows in the direction of the motion at each interval. 4 Select an appropriate material for the cam follower body and shaft. (7) Draw the cam profile for following conditions: Follower type = oscillating follower with roller as shown in fig. This will be the cam lobe. Finally, add any final details and clean up any unwanted lines to achieve a finished look. So can be calculated from equation. 5 asses through the pitch point is called Pitch circle 20 mm diameter roller follower. Finally, draw the cam's shaft that will be used to attach it to other parts of the machine. Draw a horizontal line for the x-axis, representing the motion of the plate follower. A follower with Uniform Acceleration and Retardation (UAR) will accelerate and decellerate at the same rate. This line will represent the constant velocity motion of the cam. TRACE POINT, curve : The path of the follower is which coordinates of the knife edge of the follower should be (So + S, Mark points 1,2,3..in direction opposite to the direction of cam rotation. Begin by drawing a horizontal line to represent the initial position of the cam follower. as the -axis. 120 This line should be horizontal and represent the outer edge of the cam profile. Use of templates and stencils (for simple profile designs). 3 freedom (DOF) of the mechanism, you must imagine that the roller Plot the depth of the track in the front elevation from the end elevation, as shown. If necessary, adjust it to improve the engine performance. that a roller is used at the end of the follower.
The following particulars relate to a symmetrical circular cam If the cam rotates in a clockwise direction, the last line should be curved towards the center line. us of roller = 10 mm ; inward and outward strokes take place with simple harmo Draw an oval inside the circle for the harmonic motion. These are the raised portions that make contact with the tappets. oscillating motion. Draw another circle of radius equal to the distance between cam center and follower pivot point. Draw the profile of the cam when This marks the beginning of the cam profile. The fundamental principle in designing the cam profiles is still inversion, similar to that that for Analyze and measure shapes to create technical drawings. Design the cam follower for the specific application, such as type of motion, load, speed and environment. a) Radial follower Construct standard cycloids. y cam. Record the data. D series of events consisting of rises, dwells and returns. drawn to the cam profile from the radial
We know that the maximum acceleration of the follower - Course Hero Draw an arrow above the line to represent the acceleration, following the direction of the cam follower. Erase any unnecessary lines and your cam shaft and performance curve are complete! Draw a horizontal line through the center of the circle. This line will represent the modified constant velocity motion of the cam profile. Subject: Kinematics of Machinery Topic: CAM Mechanism Difficulty: High kinematics of machinery 24.2. Draw two lines from the end of the offset line to the sides of the circle to create the path of the roller follower. he profile of the cam. Make the when the envelope curve (cam profile) lies inside the pitch curve. 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. 1 23 Finally, draw a line from the end of the follower arm to the center of the circle to complete the offset roller follower type of cam. value of maximum acceleration along the path of motion. Label the distance along the X-axis (e.g. Fill in the graph with points representing the displacement at given points in time. Least radius of cam, 35. ANGLE OF ROTATION K ANGLE To create a cycloidal motion in cam design
CAM MECHANISMS - Middle East Technical University Measure the distance between the contact point and the top of the face of the follower and draw a line representing the angle of the face. Label the various components of the cam design with letters or numbers to make it easier to reference them later on. g next 30 of cam rotation. 3 Using the tip of a ruler or a compass, draw divider lines to create an evenly spaced grid along the baseline. follower moves along the fixed cam profile in the inverted mechanism. Follower, Basic Kinematics of Constrained Rigid Bodies, Disk Cam with Knife-Edge Connect the start and end points of the desired motion profile to the base circle. types of cam mechanisms.
cam profile for uniform acceleration and retardation Solved 2. A cam operating a knife-edged follower has the - Chegg Utilize solid modeling tools and software. K the cam. of 20 mm with simple harmonic motion. Use circles to represent the pivots that are used to turn the cams. intersection A of the base circle and the chapter. Draw a circular arc between the two lines at the offset point. CNC (Computer Numerical Control) milling. a minimum radius of 25 mm, rotating clockwise at a uniform speed The initial angle between the follower Return stroke during next 60 of cam rotation, and This will be the axis for the radial cam. the displacement of follower is to take place with uniform acceleration and uniform retardation. J N, curve is the path traced by a p Radius of cycloid generating circle = = 8.4 mm, Angular velocity of cam = = 62.86 rad/sec, vomax = Max. automatic type, such as printing presses, shoe machinery, textile This line represents the time it takes for the elevator to reach its maximum speed. This helps to establish the range of both the time and displacement axes of the plot. Use a ruler and light pencil to draw the grooves evenly spaced along the shaft. Draw the profile of a cam to raise a valve with S.H.M. assing through the centre of the cam, it is known a A The SimDesign file is simdesign/cam.oscillating.sim. The roller follower demands that any concave portion of the working surface must have a radius at least equal to the radius of the roller.