A folding multi-functional teaching aid

Abstract

The present invention discloses a folding multi-functional teaching aid, which includes a rotating main shaft, a base ruler, a rotating ruler, a folding ruler and a clamping mechanism. One end of the base ruler is fixedly connected to the relative bottom side of the rotating main shaft. A circular ring sleeve is fixedly connected to the top of one end of the rotating ruler. The circular ring sleeve is rotatably sleeved on the rotating main shaft and is located above the base ruler. The end of the back edge of the rotating ruler away from the base ruler is hinged to the end of the back edge of the folding ruler. The sum of the lengths of the base ruler and the folding ruler is equal to the length of the rotating ruler. The present invention integrates multiple functions, can realize the functions of drawing circles, straight lines and angle measurement, is convenient to carry, has a simple structure, ingenious design, stable functions and efficient actions, and solves the problems of a wide variety of existing teaching aids and inconvenient carrying.

Description

Technical Field

[0001] The present invention relates to the technical field of special teaching tools for teachers, and particularly relates to a folding multi-functional teaching aid. Background Art

[0002] Although we have entered the Internet era, the use of compasses, rulers, and triangular rulers is still essential in primary or secondary school mathematics teaching. However, the functions of general teaching aids are independent of each other, and due to their large body size, they are not convenient to carry around at any time.

[0003] In the prior art, there are also specially designed teaching compasses and rulers, but either they are too complex and costly, not suitable for large-scale promotion; or they are not suitable for carrying. Summary of the Invention

[0004] The purpose of the present invention is to provide a folding multi-functional teaching aid, aiming to solve the problems in the prior art proposed in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A folding multi-functional teaching aid includes a rotating main shaft, a base ruler, a rotating ruler, a folding ruler, and a clamping mechanism. One end of the base ruler is fixedly connected to the relative bottom side of the rotating main shaft. A circular ring sleeve is fixedly connected to the top of one end of the rotating ruler, and the circular ring sleeve is rotatably sleeved on the rotating main shaft and is located above the base ruler;

[0007] One side of the base ruler, the rotating ruler, and the folding ruler is provided with scales. The side provided with scales is defined as the scale side, and the side away from the scale side is defined as the back side;

[0008] The scale sides of the base ruler and the rotating ruler are both tangent to the bottom circumference of the rotating main shaft. The straight lines where the back sides of the base ruler and the rotating ruler are located both pass through the center of the bottom surface of the rotating main shaft, so that when the rotating ruler is unfolded to form a 180° angle with the base ruler, its scale side is aligned with the scale side of the base ruler, and when folded, the back side of the rotating ruler can be attached to the back side of the base ruler; One end of the back side of the rotating ruler away from the base ruler is hinged to one end of the back side of the folding ruler, so that when the folding ruler is unfolded, its scale side is aligned with the scale side of the rotating ruler, and when folded, the back side of the folding ruler is attached to the back side of the rotating ruler; The sum of the lengths of the base ruler and the folding ruler is equal to the length of the rotating ruler;

[0009] The clamping mechanism includes an L-shaped guiding locking rod, a swing rod, a compression spring and a sliding button. A cavity is provided inside the end of the folding ruler close to the rotating ruler. The L-shaped guiding locking rod is slidably arranged in the cavity along the length direction of the folding ruler. A locking hole corresponding to the L-shaped guiding locking rod is provided on the end face of the rotating ruler close to the folding ruler. The front end of the L-shaped guiding locking rod can extend out of the end face of the folding ruler and be inserted into the locking hole. The sliding button is arranged outside the folding ruler and fixedly connected to the L-shaped guiding locking rod. The compression spring is arranged between the tail end of the L-shaped guiding locking rod and the inner end face of the cavity. A locking groove thin plate is provided on one side of the L-shaped guiding locking rod, and a locking groove is provided on the locking groove thin plate. The swing rod is swingably arranged in the cavity, and the free end of the swing rod can slide along the locking groove, so that the L-shaped guiding locking rod can be clamped when it extends or retracts.

[0010] Preferably, the locking groove is a quasi-q-shaped groove composed of a guiding straight groove, a first guiding bending groove and a second guiding bending groove. In the direction that the scale side of the folding ruler faces downwards and the back side faces upwards, the guiding straight groove is parallel to the folding ruler. The first guiding bending groove is connected below one end of the guiding straight groove close to the rotating ruler. The other end of the first guiding bending groove is connected to one end of the second guiding bending groove. The other end of the second guiding bending groove is connected to the relative middle part of the guiding straight groove.

[0011] The relative middle part of the first guiding bending groove bends inwards. There are three inflection points on the outer side of the first guiding bending groove, which are inflection point b, inflection point d, and inflection point y from top to bottom. There are three inflection points on the inner side of the first guiding bending groove, which are inflection point w, inflection point c, and inflection point x from top to bottom. The inflection point w is higher than the inflection point b, and the inflection point d is higher than the inflection point c.

[0012] There is an inner inflection point v and an outer inflection point u at the connection of the second guiding bending groove and the guiding straight groove, and the inflection point u is higher than the inflection point v.

[0013] Preferably, the rotating main shaft is in the shape of a cylindrical convex platform, and successively includes a bottom cylindrical section, a middle cylindrical section and a top cylindrical section with decreasing outer diameters from bottom to top. The base ruler is fixed on the outside of the bottom cylindrical section. The circular ring sleeve is sleeved on the middle cylindrical section. The end face of the rotating ruler close to the rotating main shaft is an arc surface and matches the circumferential side of the bottom cylindrical section.

[0014] Preferably, the top cylindrical section is provided with an external thread, and an angle measuring cone is thread-matched with the top cylindrical section. The angle measuring cone is provided with angle scale lines of 0°-180°. An alignment line is provided on the circular ring sleeve. When the rotating ruler and the base ruler form 180°, the alignment line is aligned with the 180° scale on the angle measuring cone.

[0015] Preferably, a radial threaded hole is provided on the circular ring sleeve, and a rotating ruler locking screw is thread-matched in the radial threaded hole.

[0016] Preferably, the rotary ruler and the folding ruler are hinged by a double round head connecting mechanism.

[0017] Preferably, a fixed-point lifting mechanism is provided inside the rotating main shaft. The fixed-point lifting mechanism includes an adjusting knob, a limiting disc, a screw rod, a collimator retracting rod and a magnet. A screw rod perforation, a square guiding hole and a magnet accommodating cavity are sequentially arranged along the axial direction from top to bottom in the middle of the rotating main shaft. The adjusting knob is fixed to the end of the screw rod, the limiting disc is fixed on the screw rod, the screw rod passes through the screw rod perforation, and the adjusting knob and the limiting disc are respectively located above and below the screw rod perforation. The radial dimensions of the adjusting knob and the limiting disc are larger than the screw rod perforation, so that the axial degree of freedom of the screw rod is 0. The collimator retracting rod is slidably arranged in the square guiding hole, and the cross-sectional shape of the collimator retracting rod matches that of the direction guiding hole. A threaded hole matching the screw rod is provided at the top of the collimator retracting rod, and the bottom of the collimator retracting rod is connected with the magnet.

[0018] Preferably, chalk clip sliding grooves are respectively arranged on the back edges of the rotary ruler and the folding ruler. A chalk clip mechanism is slidably arranged in the chalk clip sliding grooves. The chalk clip mechanism includes a chalk clip slider matching the chalk clip sliding grooves, a chalk clip locking screw and a chalk locking screw. Two parallel U-shaped chalk sets are arranged on the outer side of the chalk clip slider, and a chalk locking threaded hole is fixedly arranged between the two U-shaped chalk sets. The chalk locking threaded hole is threadedly matched with the chalk locking screw. A chalk clip locking threaded hole is provided on the chalk clip slider, and the chalk clip locking threaded hole is threadedly matched with the chalk clip locking screw.

[0019] Preferably, the chalk clip sliding grooves include strip-shaped grooves respectively arranged at the top and bottom of the rotary ruler and the folding ruler. The chalk clip slider is U-shaped, and its open end is bent inward and matches the strip-shaped groove.

[0020] Preferably, chalk clip sliding short grooves are respectively arranged on the scale edge of the end of the base ruler far from the rotating main shaft and the scale edge of the free end of the folding ruler. When the rotary ruler and the folding ruler are both in the folded state, sliding the chalk clip mechanism to the chalk clip sliding short grooves of the base ruler and the folding ruler can fix the folded state.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention integrates multiple functions, can realize the functions of drawing circles, straight lines and angle measurement, is convenient to carry, has a simple structure, ingenious design, stable functions and high efficiency of operation, and solves the problems of various types of existing teaching aids and inconvenience in carrying. Description of the Drawings

[0022] Figure 1 is the overall structural schematic diagram of the present invention.

[0023] Figure 2Yes Figure 1 An enlarged exploded view of part A in [description].

[0024] Figure 3 An overall exploded structure diagram of the present invention.

[0025] Figure 4 A cross-sectional view of the rotating main shaft in the present invention.

[0026] Figure 5 A structure diagram of the clamping mechanism when it extends in the present invention.

[0027] Figure 6 A structure diagram of the clamping mechanism when it retracts in the present invention.

[0028] Figure 7 In the present invention Figure 5 and Figure 6 A schematic diagram of the inflection point position of the locking groove at part B.

[0029] Figure 8 A sectional view of the locking groove in the present invention.

[0030] Figure 9 A partial cross-sectional view of the end of the folding ruler in the present invention.

[0031] Figure 10 A folding state diagram of the present invention.

[0032] Figure 11 A straight ruler state diagram of the present invention.

[0033] Figure 12 An angle measurement state diagram of the present invention.

[0034] Figure 13 Yes Figure 12 An enlarged view of C in [description].

[0035] Figure 14 A compass ruler state diagram of the present invention.

[0036] In the figure: 1. Rotating main shaft, 11. Adjusting knob, 12. Limiting disc, 13. Screw rod, 14. Aiming contraction rod, 15. Magnet, 16. Angle measurement cone; 2. Base ruler; 3. Rotating ruler, 31. Ring sleeve, 32. Rotating ruler locking screw, 33. Lock hole; 4. Folding ruler; 5. Chalk clip mechanism, 51. Chalk clip slider, 52. Chalk clip locking screw, 53. Chalk locking screw, 54. U-shaped chalk kit, 55. Chalk clip sliding short groove; 6. Double round head connection mechanism, 61. Double round head connection block, 62. Sub-screw, 63. Female sleeve; 7. Clamping mechanism, 71. L-shaped guiding lock rod, 72. Swing rod, 73. Compression spring, 74. Sliding button, 75. Locking groove, 76. Guiding straight groove, 77. First guiding bending groove, 78. Second guiding bending groove. Detailed implementation mode

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further specifically described below through embodiments in conjunction with the accompanying drawings.

[0038] Embodiment: A foldable multifunctional teaching aid. As shown in the figure, it includes a rotating main shaft 1, a base ruler 2, a rotating ruler 3 and a folding ruler 4. The rotating main shaft 1 is in the shape of a cylindrical boss and is composed of three concentric cylinders with different diameters. From bottom to top, the outer diameter decreases, and they are the bottom cylindrical section, the middle cylindrical section and the top cylindrical section in sequence. One end of the base ruler 2 is fixedly connected to the side surface of the bottom cylindrical section. One end of the rotating ruler 3 is fixedly connected with a circular ring sleeve 31. Specifically, the end of the rotating ruler 3 is fixedly connected to the bottom of the circular ring sleeve 31. The circular ring sleeve 31 is rotatably sleeved on the middle cylindrical section, and the end face of the rotating ruler 3 close to the rotating main shaft 1 is an arc surface, and this arc surface matches the circumferential side surface of the bottom cylindrical section. The above settings enable the base ruler 2 and the rotating ruler 3 to rotate relative to each other through the rotation of the circular ring sleeve 31 around the rotating main shaft 1, and the heights of the base ruler 2 and the rotating ruler 3 both correspond to the bottom cylindrical section, making their heights the same. The end of the rotating ruler 3 far from the rotating main shaft 1 is rotatably connected to the folding ruler 4, and the sum of the lengths of the base ruler 2 and the folding ruler 4 is equivalent to the length of the rotating ruler 3, so that the base ruler 2, the rotating ruler 3 and the folding ruler 4 can be unfolded into a straight line, and the base ruler 2 and the folding ruler 4 can also be folded inwards to fit with the rotating ruler 3. The length after folding is the length of the rotating ruler 3.

[0039] In this embodiment, one side of the base ruler 2, the rotating ruler 3 and the folding ruler 4 is provided with scales. The side provided with scales is defined as the scale side, and the other side is the back side. When the three are unfolded into a straight line, the scale sides are on the same side and continuous.

[0040] In the above structure, the scale sides of the base ruler 2 and the rotating ruler 3 are both tangent to the circumference of the bottom cylindrical section of the rotating main shaft 1, and the straight lines where the back sides of the base ruler 2 and the rotating ruler 3 are located both pass through the center of the bottom surface of the rotating main shaft 1, so that when the rotating ruler 3 is unfolded to 180° with the base ruler 2, its scale side is aligned with the scale side of the base ruler 2, and when folded, the back side of the rotating ruler 3 can fit with the back side of the base ruler 2. One end of the back side of the rotating ruler 3 far from the base ruler 2 is hinged to one end of the back side of the folding ruler 4, so that when the folding ruler 4 is unfolded, its scale side is aligned with the scale side of the rotating ruler 3, and when folded, the back side of the folding ruler 4 fits with the back side of the rotating ruler 3.

[0041] In this embodiment, a radial threaded hole is opened on the circular ring sleeve 31, and a rotating ruler locking screw 32 is threadedly matched in the radial threaded hole. By tightening the rotating ruler locking screw 32 to make it abut against the rotating main shaft 1, the position of the rotating ruler 3 can be fixed, and by loosening the rotating ruler locking screw 32, the rotating ruler 3 can rotate freely.

[0042] In this embodiment, the back edges of the rotary ruler 3 and the folding ruler 4 are respectively provided with chalk clip sliding grooves, and the chalk clip sliding grooves include strip-shaped grooves respectively provided at the top and bottom of the rotary ruler and the folding ruler; a chalk clip mechanism 5 is slidably arranged in the chalk clip sliding grooves. The chalk clip mechanism 5 includes a chalk clip slider 51 matching the chalk clip sliding grooves, a chalk clip locking screw 52 and a chalk locking screw 53. The chalk clip slider 51 is U-shaped, and its open end is bent inwards and matches the strip-shaped groove. The chalk clip slider 51 enters the chalk clip sliding groove from the outer end of the folding ruler 4 and can slide along the chalk clip sliding groove. Two parallel U-shaped chalk sets 54 are arranged on the outer side of the chalk clip slider 51, and a chalk locking threaded hole is fixedly arranged between the two U-shaped chalk sets 54. The chalk locking threaded hole is threadedly matched with the chalk locking screw 53. After the chalk is installed in the U-shaped chalk set 54, tightening the chalk locking screw 53 can fix the chalk; a chalk clip locking threaded hole is formed in the chalk clip slider 51, and the chalk clip locking threaded hole is threadedly matched with the chalk clip locking screw 52. Tightening the chalk clip locking screw 52 can fix the chalk clip mechanism 5 at any position on the rotary ruler 3 or the folding ruler 4.

[0043] Chalk clip sliding short grooves 55 are respectively arranged on the scale edge of the end of the base ruler 2 far from the rotation main shaft 1 and the scale edge of the free end of the folding ruler 4. When the rotary ruler 3 and the folding ruler 4 are both in the folded state, the chalk clip mechanism 5 can slide within a small range along the chalk clip sliding short grooves 55. Sliding the chalk clip mechanism 5 to the chalk clip sliding short grooves 55 of the base ruler 2 and the folding ruler 4 can fix the folded state. Specifically, when the teaching aid is in the unfolded state, the chalk clip mechanism 5 can be slid into the chalk clip sliding short grooves 55 from the end of the folding ruler 4 or the base ruler 2. After the teaching aid is folded, move the chalk clip mechanism 5 to the middle of the folding ruler 4 and the base ruler 2 and fix it with the chalk clip locking screw 52, so as to fix the folded state of the teaching aid and prevent it from unfolding.

[0044] In this embodiment, the rotation of the rotating ruler 3 around the rotating main shaft 1 and the chalk clip mechanism 5 can realize drawing a circle. To avoid friction between the rotating ruler 3 and the blackboard during circle drawing, a fixed-point lifting mechanism is provided inside the rotating main shaft 1. The fixed-point lifting mechanism includes an adjusting knob 11, a limiting disc 12, a screw 13, a sighting retractable rod 14, and a magnet 15. In the middle of the rotating main shaft 1, a screw hole, a square guiding hole, and a magnet accommodating cavity are sequentially arranged from top to bottom along the axial direction. The adjusting knob 11 is fixed to the end of the screw 13, and the limiting disc 12 is fixed on the screw 13. The screw 13 passes through the screw hole, and the adjusting knob 11 and the limiting disc 12 are respectively located above and below the screw hole. The radial dimensions of the adjusting knob 11 and the limiting disc 12 are larger than the screw hole, so that the axial degree of freedom of the screw 13 is 0. The sighting retractable rod 14 is slidably arranged in the square guiding hole, and the cross-sectional shape of the sighting retractable rod 14 matches that of the square guiding hole, so that the sighting retractable rod 14 can only slide up and down and cannot rotate. A threaded hole matching the screw 13 is provided at the top of the sighting retractable rod 14, and the bottom of the sighting retractable rod 14 is fixedly connected to the magnet 15. By rotating the adjusting knob 11 to drive the screw 13 to rotate, the sighting retractable rod 14 is driven to slide up and down, and then the magnet 15 is driven to move up and down. When the magnet 15 moves upward, it can be accommodated in the magnet accommodating cavity. When the magnet 15 moves downward, it can be made lower than the bottom surface of the rotating main shaft 1. When drawing a circle, the magnet 15 is attracted to the blackboard, and there will be a certain gap between the rotating ruler 3 and the folding ruler 4 of the teaching aid and the blackboard, thus avoiding friction with the blackboard during circle drawing.

[0045] The teaching aid of this embodiment also has the function of angle measurement. Specifically, an external thread is provided on the top cylindrical section of the rotating main shaft 1, and an angle measurement cone 16 is thread-matched with the top cylindrical section. The angle measurement cone 16 can also limit the ring sleeve 31 below it, and when the angle measurement cone 16 is in the lowest limit position, there is a gap between the bottom surface of the angle measurement cone 16 and the top end surface of the ring sleeve 31 to avoid affecting the rotation of the ring sleeve 31. Angle scale lines from 0° to 180° are provided on the angle measurement cone 16, and an alignment line is provided on the ring sleeve 31. When the rotating ruler 3 and the base ruler 2 are at 180°, the alignment line is aligned with the 180° scale on the angle measurement cone 16.

[0046] When measuring an angle, keep the rotary ruler 3 and the folding ruler 4 in a straight line when unfolded. Loosen the rotary ruler locking screw 32, align the scale edge of the base ruler 2 with one side of the angle to be measured, and align the scale edges of the rotary ruler 3 and the folding ruler 4 with the other side of the angle to be measured. Then, observe the angle corresponding to the angle scale on the angle surveying cone 16 and the scale line on the ring sleeve 31 to achieve angle measurement. By adjusting the angle between the base ruler 2 and the rotary ruler 3 and observing the angle corresponding to the angle scale on the angle surveying cone 16 and the scale line on the ring sleeve 31 at the same time, when the desired angle value to be marked is reached, lock the rotary ruler locking screw 32. Then, place the teaching aid on the blackboard and draw the two sides of the desired angle along the scale edge of the base ruler 2 and the scale edge of the rotary ruler 3 respectively to achieve angle marking.

[0047] In this embodiment, the rotary ruler 3 and the folding ruler 4 are hinged through a double-round-head connection mechanism 6. The double-round-head connection mechanism 6 is mainly composed of a double-round-head connection block 61, a sub-screw 62, and a female sleeve 63. There are two through holes at appropriate positions on the double-round-head connection block 61. At the end of the rotary ruler 3 far from the rotating main shaft 1, there is an earring above and below near the back edge, and there are two through holes with the same diameter at appropriate positions on the earring. At one end of the folding ruler 4 close to the rotary ruler 3, there is also an earring above and below near the back edge, and there are also two through holes with the same diameter at appropriate positions on the earring. Two female sleeves 63 pass through the through holes of the rotary ruler, the double-round-head connection block, and the folding ruler from bottom to top respectively. There is a clearance fit between the outer circle of the female sleeve 63 and the through holes of the rotary ruler, the double-round-head connection block, and the folding ruler. There is an internal threaded hole at the upper end of the female sleeve 63. The external thread of the sub-screw 62 and the internal thread of the female sleeve 63 are mating parts. Two sub-screws 62 are tightened into the threaded holes of the female sleeve 63 from top to bottom respectively. There are counterbores on the upper and lower surfaces of the two through holes of the rotary ruler 3 and the two through holes of the folding ruler 4, so that the cap ends of the sub-screws 62 and the female sleeve 63 are both in the counterbores. Through the connection of the sub-screw 62 and the female sleeve 63, the double-round-head connection block 61 makes the connection between the rotary ruler 3 and the folding ruler 4 form a hinged relationship.

[0048] In the above structure, in order to enable the rotary ruler 3 and the folding ruler 4 to be relatively fixed after being unfolded and thus be conveniently used as a straight ruler, a clamping mechanism 7 is provided between the rotary ruler 3 and the folding ruler 4. The clamping mechanism 7 includes an L-shaped guiding locking rod 71, a swing rod 72, a compression spring 73 and a sliding button 74. Among them, the L-shaped guiding locking rod 71, the swing rod 72 and the compression spring 73 are arranged in a cavity at the end of the folding ruler 4 close to the rotary ruler 3. Specifically, the folding ruler 4 has upper and lower parts, and hollow parts are respectively provided on the opposite surfaces of the two parts. The hollow parts of the two parts form a cavity; after the clamping mechanism 7 is installed, the upper and lower parts are fixedly connected. The L-shaped guiding locking rod 71 is slidably arranged in the cavity along the length direction of the folding ruler 4. A locking hole 33 corresponding to the L-shaped guiding locking rod 71 is opened on the end face of the rotary ruler 3 close to the folding ruler 4. When the folding ruler 4 and the rotary ruler 3 are unfolded, the front end of the L-shaped guiding locking rod 71 can extend out of the end face of the folding ruler and be inserted into the locking hole 33; the other end of the L-shaped guiding locking rod 71 passes through the side wall of the folding ruler 4 and extends outside the folding ruler 4 to be fixedly connected with the sliding button 74. A strip-shaped groove is opened on the side wall of the folding ruler 4 for the L-shaped guiding locking rod 71 to move back and forth. The compression spring 73 is arranged between the tail end of the L-shaped guiding locking rod 71 and the inner end face of the cavity. When the L-shaped guiding locking rod 71 moves backward, the compression spring 73 is further compressed; a locking groove thin plate is provided on one side of the L-shaped guiding locking rod 71, and a locking groove 75 is opened on the locking groove thin plate; the swing rod 72 is swingably arranged in the cavity. Specifically, one end of it is hinged on the plane below the cavity of the folding ruler 4, so that it can swing in the horizontal direction. The free end of the swing rod 72 is bent downward by 90°, so that the bent part is located in the locking groove 75. When the L-shaped guiding locking rod 71 moves back and forth, the free end of the swing rod 72 can slide relatively in the locking groove 75 along the locking groove 75 and drive the swing rod 72 to swing.

[0049] The above-mentioned locking groove 75 is specifically a quasi-q-shaped groove composed of a guiding straight groove 76, a first guiding bending groove 77 and a second guiding bending groove 78. Taking the direction when the scale side of the folding ruler 4 faces downward and the back side faces upward as a reference, the guiding straight groove 76 is parallel to the folding ruler 4. The first guiding bending groove 77 is connected below one end of the guiding straight groove 76 close to the rotary ruler 3. The other end of the first guiding bending groove 77 is connected to one end of the second guiding bending groove 78, and the other end of the second guiding bending groove 78 is connected to the relative middle part of the guiding straight groove 76.

[0050] Several key points are provided on the locking groove 75. It should be noted that the "high" and "low" of the points are both based on Figure 7 the direction shown when the scale side of the folding ruler 4 faces downward and the back side faces upward, which is only limited to explaining the working principle of the retraction and ejection of the L-shaped guiding locking rod 71; the swing of the swing rod 72 depends on the shape of the locking groove 75. As the L-shaped guiding locking rod 71 makes a linear reciprocating motion, the sliding of the free end of the swing 72 in the locking groove 75 causes the swing rod 72 to swing.

[0051] Specifically, the relative middle part of the first guiding bending groove 77 bends inward. There are three inflection points on the outer side of the first guiding bending groove 77, which are inflection point b, inflection point d, and inflection point y from top to bottom in sequence; there are three inflection points on the inner side of the first guiding bending groove 77, which are inflection point w, inflection point c, and inflection point x from top to bottom in sequence; inflection point w is higher than inflection point b, and inflection point d is higher than inflection point c; at the connection between the second guiding bending groove 78 and the guiding straight groove 76, there is an inner inflection point v and an outer inflection point u, and inflection point u is higher than inflection point v.

[0052] When the rotating ruler 3 and the folding ruler 4 are unfolded from the folded state to a straight line, the free end of the swing rod 72 is initially located at the inflection point c of the locking groove 75, and the compression spring 73 is in a compressed state, so that the L-shaped guiding locking rod 71 has a tendency to extend outward under the action of the compression spring 73, while the free end of the swing rod 72 presses against the locking groove 75 at the position of the inflection point c to prevent it from extending. If based on Figure 7 the shown direction, the sliding button 76 is slid to the right to drive the L-shaped guiding locking rod 71 to move to the right, and the compression spring 73 is further compressed. Since the inflection point c is lower than the inflection point d, the free end of the swing rod 72 contacts the edge of the locking groove of the "d-y" section and is guided by the "d-y" section to rotate clockwise by a certain angle from the shown horizontal position until the free end of the swing rod 72 slides to the inflection point y; then the sliding button 74 is released, and through the rebound action of the compression spring 73, the L-shaped guiding locking rod 71 will move to the left, and the free end of the swing rod 72 will slide along the second guiding bending groove 78 and then enter the guiding straight groove 76, that is, the free end of the swing rod 72 slides from the inflection point y through the inflection point z to the rightmost inflection point a. At this time, the L-shaped guiding locking rod 71 is inserted into the locking hole 33 of the rotating ruler, realizing the clamping of the rotating ruler 3 and the folding ruler 4.

[0053] When the rotating ruler 3 and the folding ruler 4 are folded from the unfolded state, the free end of the swing rod 72 is initially located at the inflection point a of the locking groove 75. The sliding button 74 is slid to the right to drive the L-shaped guide locking rod 71 to move right, and the free end of the swing rod 72 will move left relative to the guide straight groove 76 of the locking groove. It should be noted that since the inflection point u is higher than the inflection point v, the free end of the swing rod 72 will not slide towards the second guide bending groove 78 when the teaching aid is placed horizontally (only in the extreme case where the scale side is facing downwards, the swing rod 72 may slide into the second guide bending groove 78 due to its own gravity. However, according to the usage habits of most people, when the rotating ruler 3 and the folding ruler 4 are folded, the scale side is generally not completely downward; even in the posture with the scale side facing downwards, as long as the moving speed of the L-shaped guide locking rod 71 is not particularly slow, since the inflection point u is higher than the inflection point v, theoretically the free end of the swing rod 72 will not slide into the second guide bending groove 78 at this moment; further, even in extreme cases, the free end of the swing rod 72 slides into the second guide bending groove The free end of the swing rod 72 slides along the guide straight groove 76 to the leftmost end and then enters the first guide bending groove 77. Since the inflection point b is lower than the inflection point w, the free end of the swing rod 72 will move to the inflection point b and cannot continue to move left. Then release the sliding button 74. Through the rebound effect of the compression spring 73, the L-shaped guide locking rod 71 will move to the left, and the free end of the swing rod 72 will contact the first guide bending groove 77. The "wc" section of 7 is guided by the "wc" end and finally slides to the position of the inflection point c. Under the action of the compression spring 73, the free end of the rocker arm 72 presses the lock groove 75 at the inflection point c to prevent the L-shaped guide locking rod 71 from moving. At this time, the L-shaped guide locking rod 71 is retracted into the cavity and no longer extends out. In this process, after the L-shaped guide locking rod 71 is retracted, the folding ruler 4 can be folded, and then clamped between the scale edges of the folding ruler and the base ruler by the aforementioned chalk clamp mechanism, thus completing the folding of the teaching aid.

[0054] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A folding multi-functional teaching aid, characterized in that, it includes a rotating main shaft, a base ruler, a rotating ruler, a folding ruler and a clamping mechanism. One end of the base ruler is fixedly connected to the relative bottom side of the rotating main shaft. A circular ring sleeve is fixedly connected to the top of one end of the rotating ruler. The circular ring sleeve is rotatably sleeved on the rotating main shaft and is located above the base ruler; scales are provided on one side of the base ruler, the rotating ruler and the folding ruler. The side with the scale is defined as the scale side, and the side away from the scale side is defined as the back side; the scale sides of the base ruler and the rotating ruler are both tangent to the bottom circumference of the rotating main shaft. The straight lines where the back sides of the base ruler and the rotating ruler are located both pass through the center of the bottom surface of the rotating main shaft, so that when the rotating ruler is unfolded to be 180° with the base ruler, its scale side is aligned with the scale side of the base ruler, and when folded, the back side of the rotating ruler can fit with the back side of the base ruler; the end of the back side of the rotating ruler away from the base ruler is hinged to one end of the back side of the folding ruler, so that when the folding ruler is unfolded, its scale side is aligned with the scale side of the rotating ruler, and when folded, the back side of the folding ruler fits with the back side of the rotating ruler; the sum of the lengths of the base ruler and the folding ruler is equal to the length of the rotating ruler; the clamping mechanism includes an L-shaped guiding lock rod, a swing rod, a compression spring and a sliding button. A cavity is provided inside the end of the folding ruler close to the rotating ruler. The L-shaped guiding lock rod is slidably arranged in the cavity along the length direction of the folding ruler. A lock hole corresponding to the L-shaped guiding lock rod is opened on the end face of the rotating ruler close to the folding ruler. The front end of the L-shaped guiding lock rod can extend out of the end face of the folding ruler and be inserted into the lock hole; the sliding button is arranged outside the folding ruler and is fixedly connected to the L-shaped guiding lock rod. The compression spring is arranged between the tail end of the L-shaped guiding lock rod and the inner end face of the cavity; a lock groove thin plate is provided on one side of the L-shaped guiding lock rod, and a lock groove is opened on the lock groove thin plate. The swing rod is swingably arranged in the cavity. The free end of the swing rod can slide along the lock groove, so that the L-shaped guiding lock rod can be clamped when it extends out or retracts; the lock groove is a quasi-q-shaped groove composed of a guiding straight groove, a first guiding bending groove and a second guiding bending groove. In the direction where the scale side of the folding ruler is downward and the back side is upward, the guiding straight groove is parallel to the folding ruler. The first guiding bending groove is connected below one end of the guiding straight groove close to the rotating ruler. The other end of the first guiding bending groove is connected to one end of the second guiding bending groove. The other end of the second guiding bending groove is connected to the relative middle part of the guiding straight groove; the relative middle part of the first guiding bending groove bends inward. There are three inflection points on the outer side of the first guiding bending groove, which are inflection point b, inflection point d, and inflection point y from top to bottom; there are three inflection points on the inner side of the first guiding bending groove, which are inflection point w, inflection point c, and inflection point x from top to bottom; inflection point w is higher than inflection point b, and inflection point d is higher than inflection point c; at the connection of the second guiding bending groove and the guiding straight groove, there is an inner inflection point v and an outer inflection point u, and inflection point u is higher than inflection point v; a radial threaded hole is opened on the circular ring sleeve, and a rotating ruler locking screw is threadedly matched in the radial threaded hole.

2. The folding multi-functional teaching aid according to claim 1, characterized in that, The rotating main shaft is in the shape of a cylindrical boss, and successively includes a bottom cylindrical section, a middle cylindrical section, and a top cylindrical section with decreasing outer diameters from bottom to top. The base scale is fixed on the outer side of the bottom cylindrical section. The ring sleeve is sleeved on the middle cylindrical section. The end face of the rotating scale close to the rotating main shaft is an arc surface and matches the circumferential side of the bottom cylindrical section.

3. A folding multi-functional teaching aid according to claim 2, characterized in that the top cylindrical section is provided with an external thread, and an angle measuring cone is thread-matched with the top cylindrical section. The angle measuring cone is provided with angle scale lines of 0° - 180°. An alignment line is provided on the ring sleeve. When the rotating scale and the base scale form 180°, the alignment line is aligned with the 180° scale on the angle measuring cone.

4. A folding multi-functional teaching aid according to claim 1, characterized in that the rotating scale and the folding scale are hinged by a double-round-head connection mechanism.

5. A folding multi-functional teaching aid according to claim 1 or 2, characterized in that a fixed-point lifting mechanism is provided inside the rotating main shaft. The fixed-point lifting mechanism includes an adjustment knob, a limiting disc, a screw rod, a sighting contraction rod, and a magnet. A screw rod through-hole, a square guiding hole, and a magnet accommodating cavity are successively provided along the axial direction from top to bottom in the middle of the rotating main shaft. The adjustment knob is fixed to the end of the screw rod. The limiting disc is fixed on the screw rod. The screw rod passes through the screw rod through-hole, and the adjustment knob and the limiting disc are respectively located above and below the screw rod through-hole. The radial dimensions of the adjustment knob and the limiting disc are larger than the screw rod through-hole, so that the axial freedom degree of the screw rod is 0. The sighting contraction rod is slidably arranged in the square guiding hole, and the cross-sectional shape of the sighting contraction rod matches the direction guiding hole. A threaded hole matching the screw rod is provided at the top of the sighting contraction rod, and the bottom of the sighting contraction rod is connected to the magnet.

6. A folding multi-functional teaching aid according to claim 1, characterized in that chalk clip sliding grooves are respectively provided on the back edges of the rotating scale and the folding scale. A chalk clip mechanism is slidably arranged in the chalk clip sliding grooves. The chalk clip mechanism includes a chalk clip slider matching the chalk clip sliding grooves, a chalk clip locking screw, and a chalk locking screw. Two parallel U-shaped chalk sets are provided on the outer side of the chalk clip slider. A chalk locking threaded hole is fixed between the two U-shaped chalk sets. The chalk locking threaded hole is thread-matched with the chalk locking screw. A chalk clip locking threaded hole is provided on the chalk clip slider. The chalk clip locking threaded hole is thread-matched with the chalk clip locking screw.

7. A folding multi-functional teaching aid according to claim 6, characterized in that the chalk clip sliding grooves include strip-shaped grooves respectively provided at the top and bottom of the rotating scale and the folding scale. The chalk clip slider is U-shaped, and its open end is bent inward and matches the strip-shaped grooves.

8. A folding multi-functional teaching aid according to claim 7, characterized in that Chalk clip sliding short grooves are respectively provided on the scale edge of the end of the base ruler away from the rotation main shaft and the scale edge of the free end of the folding ruler. When both the rotating ruler and the folding ruler are in the folded state, sliding the chalk clip mechanism into the chalk clip sliding short grooves of the base ruler and the folding ruler can fix the folded state.

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