Teaching Convex Profile Drawing Instrument

Abstract

A teaching convex profile drawing device relates to the field of teaching aids. It includes a follower motion law curve tracking component, a convex profile drawing component, and a parameter adjustment component. The parameter adjustment component includes a base circle radius adjustment component and an offset distance adjustment component. The base circle radius adjustment component is mounted on the moving guide rail of the follower motion law curve tracking component, and the offset distance adjustment component is placed within the convex profile drawing component. The follower motion law curve tracking component and the convex profile drawing component are connected by a synchronous linkage and are fixedly mounted on a base. This device eliminates the need for equal division of the follower motion law curve, allows for continuous drawing, achieves high profile accuracy, fast drawing speed, and a simple process.

Description

Technical Field

[0001] This invention relates to the field of teaching aids, and in particular to a convex contour drawing instrument for teaching. Background Technology

[0002] Cam mechanisms can realize complex motion patterns of followers. By properly designing the profile curve of the cam, the follower can achieve any predetermined motion pattern.

[0003] After selecting the type of cam mechanism and the motion law of the follower based on the application and working requirements, the cam profile curve can be designed according to the selected base circle radius and other parameters. In university courses on "Principles of Machinery," the design of the cam profile curve is usually done graphically, given the known motion law of the follower. However, drawing the cam profile using the graphical method based on the inversion principle requires dividing the follower motion law curve into equal parts, finding the corresponding cam profile point at each division point, and then connecting the points with a curve to obtain the profile curve. This process is cumbersome, results in low curve accuracy, and is not conducive to students' intuitive understanding of the principle. Summary of the Invention

[0004] The purpose of this invention is to provide a cam profile drawing instrument for teaching purposes. This instrument can draw a cam profile corresponding to the known motion law of the follower based on the known motion law of the follower, without needing to equally divide the motion law curve of the follower. This solves the problem that designing cam profile curves using the drawing method is too cumbersome.

[0005] The technical solution of the present invention: The teaching convex contour drawing instrument includes a follower motion law curve tracking component, a convex contour drawing component, and a parameter adjustment component, wherein the parameter adjustment component is connected to the follower motion law curve tracking component and the convex contour drawing component, the follower motion law curve tracking component and the convex contour drawing component are connected by a synchronous linkage, and the follower motion law curve tracking component and the convex contour drawing component are fixedly installed on the base.

[0006] The follower motion law curve tracking component includes slider I2, slider II5, slider III8, slider IV26, moving guide rail 6, tracking pen 7, fixed guide rail II25, and fixed guide rail III28. The moving guide rail 6 is mounted on slider II5 and slider III8 and can move laterally. The tracking pen 7 is mounted on the moving guide rail 6. A platform 4 is provided below the tracking pen 7 and is fixed on the base 1. Slider I2 is mounted on the fixed guide rail III28, and slider III26 is mounted on the fixed guide rail II25. Slider I2 and slider IV26 can move longitudinally along the guide rail. Slider I2 and slider II5 are connected together by slider connecting bracket I3, and slider IV26 and slider III8 are connected together by slider connecting bracket II27.

[0007] The movable guide rail 6 is connected to the adjusting plate 10 and is tightened by bolts and nuts 9.

[0008] The convex contour drawing component includes a drawing pen 14, a drawing pen mounting bracket 15, a disc 16, a gear 17, a rack 18, a vertical shaft 19, a rack seat 20, an offset distance adjustment component 21, a fixed guide rail 122, and a slider 23. Slider V 23 is connected to slider IV 26 via a synchronous connecting rod 24 and can move synchronously with slider IV 26. The offset distance adjustment component 21 is fixed to slider IV 26, and the vertical shaft 19 is fixed to the offset distance adjustment component 21. The disc 16 is fixed to the gear 17. The gear 17 is mounted on the vertical shaft 19 and can rotate around the vertical shaft 19. The rack 18 is fixed to the rack seat 20 and meshes with the gear 17.

[0009] The drawing pen 14 is mounted on the drawing pen mounting bracket 15, which is connected to the adjustment plate 10 via a hinge 13. A limiting plate 11 is mounted below the adjustment plate 10 via bolts and nuts 12 to prevent the drawing pen mounting bracket 15 from rotating around the hinge 13, thus ensuring the stability of the drawing pen 14 during drawing.

[0010] The parameter adjustment components include a base circle radius adjustment component and an offset distance adjustment component 21.

[0011] The base circle radius adjustment component includes a movable guide rail 6, bolts and nuts 9, and an adjustment plate 10. The adjustment plate 10 and the movable guide rail 6 have the same size sliding grooves and are connected by bolts and nuts 9.

[0012] The offset distance adjustment component 21 includes a lead screw 29, a vertical shaft mounting base 30, a lead screw mounting base 31, and a bearing 32. The lead screw 29 has smooth shafts at both ends and threads machined in the middle, and is mounted on the lead screw mounting base 31 via the bearing 32. The vertical shaft mounting base 30 has threaded holes and is installed on the threaded part in the middle of the lead screw 29.

[0013] The beneficial technical effects of this invention are: This device has a simple structure, eliminates the need for equally dividing the follower motion law curve, allows for continuous drawing, achieves high profile accuracy, fast drawing speed, and a simple process. When used in university courses on "Principles of Machinery," it can help students draw the cam profile corresponding to the known follower motion law, enabling a more vivid and intuitive study of the influence of basic cam mechanism parameters on the cam profile and the motion distortion problem during cam motion. It also facilitates understanding and mastering the basic idea and application of the reversal method. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] Figure 2 for Figure 1 Top view.

[0016] Figure 3 This is a schematic diagram of the base circle radius adjustment component.

[0017] Figure 4 This is a schematic diagram of the offset distance adjustment component. Detailed Implementation

[0018] The technical solution of the invention will be further described with reference to the accompanying drawings.

[0019] like Figure 1 , Figure 2 As shown, the teaching convex contour drawing instrument includes a follower motion law curve tracking component, a convex contour drawing component, and a parameter adjustment component. The parameter adjustment component is connected to the follower motion law curve tracking component and the convex contour drawing component. The follower motion law curve tracking component and the convex contour drawing component are connected by a synchronous linkage. The follower motion law curve tracking component and the convex contour drawing component are fixedly installed on the base 1.

[0020] The follower motion law curve tracking component includes slider I2, slider II5, slider III8, slider IV26, moving guide rail 6, tracking pen 7, fixed guide rail II25, and fixed guide rail III28. Moving guide rail 6 is mounted on slider II5 and slider III8 and can move laterally. Tracking pen 7 is mounted at a suitable position on moving guide rail 6. Platform 4 is located below tracking pen 7 and is fixed to base 1. Slider I2 is mounted on fixed guide rail III28, and slider III26 is mounted on fixed guide rail II25. Slider I2 and slider IV26 can move longitudinally along the guide rails. Slider I2 and slider II5 are connected by slider connecting bracket I3, and slider IV26 and slider III8 are connected by slider connecting bracket II27.

[0021] The movable guide rail 6 is connected to the adjusting plate 10 and is tightened by bolts and nuts 9.

[0022] The convex contour drawing component includes a drawing pen 14, a drawing pen mounting bracket 15, a disc 16, a gear 17, a rack 18, a vertical shaft 19, a rack seat 20, an offset distance adjustment component 21, a fixed guide rail 122, and a slider 23. Slider V 23 is connected to slider IV 26 via a synchronous connecting rod 24 and can move synchronously with slider IV 26. The offset distance adjustment component 21 is fixed to slider IV 26, and the vertical shaft 19 is fixed to the offset distance adjustment component 21. The disc 16 is fixed to the gear 17. The gear 17 is mounted on the vertical shaft 19 and can rotate around the vertical shaft 19. The rack 18 is fixed to the rack seat 20 and meshes with the gear 17.

[0023] The drawing pen 14 is mounted on the drawing pen mounting bracket 15, which is connected to the adjusting plate 10 via a hinge 13. A limiting plate 11 is mounted below the adjusting plate 10 via bolts and nuts 12, preventing the drawing pen mounting bracket 15 from rotating around the hinge 13 and ensuring the stability of the drawing pen 14 during drawing. When changing the drawing pen or adjusting parameters such as the base circle radius and offset distance, the bolts and nuts 12 can be loosened, and the limiting plate can be rotated 90° in the horizontal plane. At this time, the limiting plate 11 will move away from the drawing pen mounting bracket 15, allowing the drawing pen mounting bracket 15 to rotate counterclockwise around the hinge 13, thus lifting the drawing pen 14. This prevents the pen tip from contacting the paper, ensuring a clean drawing and facilitating paper replacement.

[0024] The parameter adjustment components include a base circle radius adjustment component and an offset distance adjustment component. The base circle radius adjustment component includes a moving guide rail 6, a bolt and nut 9, and an adjusting plate 10. The adjusting plate 10 and the moving guide rail 6 have grooves of the same size and are connected together by the bolt and nut 9. When adjusting the cam base circle radius, first loosen the bolt and nut 9, then move the adjusting plate 10 to the required position, and then tighten the bolt and nut 9.

[0025] The offset distance adjustment component consists of a lead screw 29, a vertical shaft mounting base 30, a lead screw mounting base 31, and a bearing 32. The lead screw 29 has smooth shafts at both ends and a threaded section in the middle, and is mounted on the lead screw mounting base 31 via the bearing 32. The vertical shaft mounting base 30 has a threaded hole and is installed on the threaded section of the lead screw 29. When the lead screw 29 is rotated, the vertical shaft mounting base 30 can move, causing the disc mounted on the vertical shaft 19 to move simultaneously, thereby adjusting the offset distance. This device can draw the corresponding cam profile curve based on the known follower motion law curve, unaffected by the cam's rotational angular velocity. The base circle radius is adjustable according to design requirements. The offset distance adjustment component is used to adjust the eccentric distance, thus used to draw an eccentric cam.

[0026] This invention is based on the basic idea of ​​the reversal method. Given the motion law of the follower, the corresponding cam profile can be drawn according to the stroke of the follower and the angle through which the cam rotates.

[0027] For a cam mechanism with a central axis, before drawing the cam profile, adjust the drawing pen 14 and the rotation center of the disk 16 to be on the same vertical line.

[0028] First, draw the motion curve of the follower to be realized on graph paper. Then, fix the graph paper on platform 4 and fix the white paper for drawing the convex contour on disk 16. The operator holds the tracking pen 7 and slowly moves the pen tip along the motion curve of the follower. At this time, the moving guide rail 6 makes a combined longitudinal and lateral movement, and the drawing pen 14 also moves with the moving guide rail 6, thus drawing the curve on the white paper. The lateral displacement of the drawing pen 14 is the stroke of the follower. Slider 5 drives slider 2, slider 8 drives slider 26 to move longitudinally at the same time. Slider 26 drives slider 23 to move longitudinally through the synchronous connecting rod 24. Since gear 17 meshes with rack 18, and rack 18 is fixed, gear 17 and disk 16 mounted on gear 17 rotate around its center while moving with slider 23. The angle through which disk 16 rotates is the angle through which the cam rotates when the follower moves a certain stroke. When the tracking pen 7 moves along the motion law curve of the follower for one cycle, the disk 16 rolls once, and the drawing pen can draw a complete convex contour line.

[0029] Example 2

[0030] Everything else is the same as in Example 1, except that it is used to draw an eccentric cam.

[0031] For the offset cam mechanism, before drawing the cam profile, first adjust the center of rotation of the drawing pen 14 and the disk 16 to be on the same vertical line. Then rotate the lead screw 29, the vertical shaft mounting base 30 moves, and drives the disk 16 mounted on the vertical shaft 19 to move at the same time. Stop when the horizontal distance between the center of rotation of the drawing pen 14 and the disk 16 reaches the required offset distance.

[0032] The conventional method uses a graphical approach based on the principle of reversal to draw the cam profile. This requires dividing the follower's motion curve into equal parts, finding the corresponding cam profile point at each division point, and then connecting the points with a curve to obtain the profile curve. This process is cumbersome and results in low curve accuracy. This device eliminates the need to divide the follower's motion curve into equal parts, allows for continuous drawing, provides high profile accuracy, fast drawing speed, and a simple process.

Claims

1. A convex profile drawing instrument for teaching purposes includes a follower motion law curve tracking component, a convex profile drawing component, and a parameter adjustment component, characterized in that: The parameter adjustment component includes a base circle radius adjustment component and an offset distance adjustment component (21). The base circle radius adjustment component is installed on the moving guide rail (6) of the follower motion law curve tracking component. The offset distance adjustment component (21) is placed in the convex profile drawing component. The follower motion law curve tracking component and the convex profile drawing component are connected by a synchronous linkage. The follower motion law curve tracking component and the convex profile drawing component are fixedly installed on the base. The follower motion law curve tracking component includes slider I (2), slider II (5), slider III (8), and slider IV (26). The system consists of a moving guide rail (6), a tracking pen (7), a fixed guide rail II (25), and a fixed guide rail III (28). The moving guide rail (6) is mounted on slider II (5) and slider III (8) and can move laterally. The tracking pen (7) is mounted on the moving guide rail (6). A platform (4) is set below the tracking pen (7) and the platform (4) is fixed on the base (1). Slider I (2) is mounted on the fixed guide rail III (28), and slider III (26) is mounted on the fixed guide rail II (25). Slider I (2) and slider IV (26) can move longitudinally along the guide rail. Slider I (2) and slider III (28) are connected to each other. Block II (5) is connected together by slider connecting bracket I (3), and slider IV (26) and slider III (8) are connected together by slider connecting bracket II (27); the convex contour drawing component includes a drawing pen (14), a drawing pen mounting bracket (15), a disc (16), a gear (17), a rack (18), a vertical shaft (19), a rack seat (20), an offset distance adjustment component (21), a fixed guide rail I (22), and a slider V (23). Slider V (23) is connected to slider IV (26) through a synchronous connecting rod (24) and can move synchronously with slider IV (26). The offset distance adjustment component (21) is fixed on the slider IV (26), the vertical shaft (19) is fixed on the offset distance adjustment component (21), the disc (16) is fixed on the gear (17), the gear (17) is mounted on the vertical shaft (19) and can rotate around the vertical shaft (19), the rack (18) is fixed on the rack seat (20) and meshes with the gear (17). The base circle radius adjustment component includes a moving guide rail (6), bolts and nuts (9), and an adjustment plate (10). The adjustment plate (10) and the moving guide rail (6) have the same size grooves and are connected by bolts and nuts (9).

2. The convex contour drawing instrument for teaching according to claim 1, characterized in that: The drawing pen (14) is mounted on the drawing pen mounting bracket (15). The drawing pen mounting bracket (15) is connected to the adjustment plate (10) via a hinge (13). The limiting plate (11) is mounted below the adjustment plate (10) via bolts and nuts (12) to prevent the drawing pen mounting bracket (15) from rotating around the hinge (13) and to ensure the stability of the drawing pen (14) when drawing.

3. The convex contour drawing instrument for teaching according to claim 1, characterized in that: The offset distance adjustment component (21) includes a lead screw (29), a vertical shaft mounting base (30), a lead screw mounting base (31), and a bearing (32). The two ends of the lead screw (29) are smooth shafts, and the middle is threaded. It is mounted on the lead screw mounting base (31) through the bearing (32). The vertical shaft mounting base (30) has a threaded hole and is installed on the threaded part in the middle of the lead screw (29).

4. The convex contour drawing instrument for teaching as described in claim 1, characterized in that: The method of use is as follows: Draw the motion law curve of the follower to be realized on the coordinate paper, then place the coordinate paper on the platform (4) and fix it. Place the white paper for drawing the convex contour on the disc (16) and fix it. The operator holds the tracking pen (7) and lets the pen tip move slowly along the motion law curve of the follower. Since the tracking pen (7) is installed on the moving guide rail (6), the movement of the tracking pen (7) drives the moving guide rail (6) to make a composite movement in the longitudinal and transverse directions. The drawing pen (14) also moves with the moving guide rail (6) to draw the curve on the white paper. The transverse displacement of the drawing pen (14) is the stroke of the follower. The slider II (5) drives the slider I (2) Slider III (8) drives slider IV (26) to move longitudinally at the same time. Slider IV (26) drives slider V (23) to move longitudinally through synchronous connecting rod (24). Since gear (17) meshes with rack (18) and rack (18) is fixed, gear (17) and disk (16) mounted on gear (17) rotate around its center while sliding with slider V (23). The angle through which disk (16) rotates is the angle through which cam rotates when follower moves a certain distance. Tracking pen (7) moves along follower motion law curve for one cycle, disk (16) rolls once, and drawing pen can draw complete convex contour line.

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