Double-track double-scale compasses

Abstract

The utility model provides a pair of double-track double-scale compasses, which relates to the technical field of compasses, and comprises a fixed connector, a first support leg, a second support leg, a positioning needle and a lead core, the first support leg and the second support leg are arranged in the fixed connector and are coaxially arranged, the positioning needle and the lead core are respectively arranged at the lower ends of the first support leg and the second support leg, and the first support leg and the second support leg are connected with each other. An arc-shaped first graduated scale is arranged at the upper end of the first supporting leg, the radius of the first graduated scale is larger than that of the second graduated scale, a groove is formed in the connecting axis of the first supporting leg and used for clamping the connecting axis of the second supporting leg, and an arc-shaped second graduated scale is arranged at the upper end of the second supporting leg and used for clamping the connecting axis of the second supporting leg. The first graduated scale and the second graduated scale are coaxial and different in size after being installed, and scales are arranged on the first graduated scale and the second graduated scale. The pair of compasses solves the problem that the existing compasses are inaccurate in precision when being used.

Description

Technical Field

[0001] The utility model relates to the technical field of compasses, in particular to a double-track double-scale compass. Background Art

[0002] The existing metal compasses on the market may have parts falling off and rusting during use. After long-term use, they are prone to loosening and sliding, resulting in reduced accuracy. In addition, an angle ruler is required to proceed to the next step.

[0003] After actual use, it was found that a "digital compass" currently on the market has the following problems: 1. The error is too large. Different adjustment methods can produce different radius sizes under the same scale. The error is about 3mm or larger during actual use; 2. Although the "push-type design" eliminates the cumbersome storage box, when it is taken out of a school bag, the positioning pin will always be squeezed in the bag and pressed out. At this time, it will either get stuck in the school bag or prick your hand. Summary of the invention

[0004] The utility model provides a double-track double-scale compass to solve the problems of inaccurate precision and large error in the use of the existing compass.

[0005] In order to solve the technical problem, the utility model adopts the following technical solution: a double-track double-scale compass, comprising a fixed connector, a first leg, a second leg, and a positioning needle, wherein the first leg and the second leg are arranged in the fixed connector and are coaxially arranged, the positioning needle and the lead are respectively installed at the lower ends of the first leg and the second leg, and the lower ends of the first leg and the second leg are respectively provided with a core fixing cover for fixing the positioning needle and the lead; characterized in that,

[0006] The upper end of the first leg is provided with a first arc-shaped scale and a first connector, a positioning groove is provided inside the first connector, the upper end of the second leg is provided with a second arc-shaped scale and a second connector, the first scale and the second scale are coaxial scales with different radii after installation, the radius of the first scale is greater than the radius of the second scale, and scales are provided on the first scale and the second scale;

[0007] The first leg and the second leg are coaxially connected in the fixed connection head through a rotating shaft, and the first leg and the second leg can swing around the rotating shaft;

[0008] A window is provided on the connecting plate on the side of the fixed connecting head, and scale pointers are symmetrically arranged at the upper and lower ends of the window to facilitate viewing and calibration of the scale.

[0009] Furthermore, the thicknesses of the first scale, the second scale, the first leg, and the second leg are consistent.

[0010] Furthermore, a first reinforcing rib is provided between the first scale and the first connecting head, and a second reinforcing rib is provided between the second scale and the second connecting head, and the connection strength and rigidity of the first scale and the second scale are ensured by the provision of the reinforcing rib.

[0011] Furthermore, there are two core fixing covers, which are threadedly connected to the first leg and the second leg. A mounting groove is provided at the center of the thread at the lower end of the leg for mounting a positioning pin or a lead core.

[0012] Furthermore, one end of the rotating shaft has a positioning step, and the other end has an external thread, which is fixed by a locking nut.

[0013] Furthermore, the outer movable sleeves of the first leg and the second leg are provided with a shell.

[0014] The beneficial effects of the utility model are as follows: the utility model is provided with scales on both legs, and the double scales are used to reduce errors and ensure the accuracy of angles. The provision of the first reinforcing rib increases the stability of the first leg, making it convenient for the first reinforcing rib to clamp the second scale. A window and a pointer used in conjunction with the scale are provided on the fixed connecting head, which is convenient for the compass to accurately control and calibrate the angle when in use. The compass is fixed by a rotating shaft and a locking nut to reduce the wear of the rotating shaft on the legs, and the two legs can be opened and closed independently without affecting each other. A core fixing cover is provided at the lower end of the leg for threaded connection, which is convenient for the replacement of the lead core. The inaccurate precision of the existing compass when in use can be effectively solved, and the problem of needing to use an additional protractor when drawing is also solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0016] Figure 2 It is a side view structural schematic diagram of the utility model;

[0017] Figure 3 This is a schematic diagram of the structure of the utility model with the legs opened;

[0018] Figure 4 This is a schematic diagram of the structure of the connection between the core fixing cover and the supporting legs of the utility model;

[0019] Figure 5 This is a front view of the first leg of the utility model;

[0020] Figure 6 It is a left view of the first leg of the utility model;

[0021] Figure 7 It is a right side view of the first leg of the utility model;

[0022] Figure 8It is a front view of the second leg of the utility model;

[0023] Fig. 9 It is a right side view of the second leg of the utility model;

[0024] Fig.10 This is a schematic diagram of the installation structure of the first leg and the second leg of the utility model;

[0025] Fig.11 It is a schematic diagram of the structure of the utility model with a housing;

[0026] Fig.12 This is an experimental diagram of the compass scale marking of the utility model.

[0027] In the figure: 1. fixed connector, 2. window, 3. second scale, 4. second leg, 5. core cap, 6. positioning pin, 7. lead core, 8. first leg, 9. first reinforcing rib, 10. first scale, 11. scale pointer, 12. rotating shaft, 1201. locking nut, 13. first connecting hole, 14. first connector, 15. positioning groove, 16. second connector, 17. second connecting hole, 18. outer shell, 19. second reinforcing rib. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] refer to Figures 1 to 11 A double-track double-scale compass, comprising a fixed connector 1, a first leg 8, a second leg 4, and a positioning pin 6. The first leg 8 and the second leg 4 are arranged in the fixed connector and are coaxially arranged. The positioning pin 6 and the lead core 7 are respectively installed at the lower ends of the first leg 8 and the second leg 4. The lower ends of the first leg 8 and the second leg 4 are provided with a fixed core cover 5 for fixing the positioning pin 6 or the lead core 7. The upper end of the first leg is provided with an arc-shaped first scale 10 and a first connector 14. A positioning groove 15 is provided inside the first connector. The two side walls of the positioning groove are provided with a first connecting hole 13. The upper end of the second leg A second arc-shaped scale 3 and a second connector 16 are provided at the end, and a second connecting hole 17 is provided on the second connecting head. After installation, the first scale and the second scale are coaxial scales with different radii. The radius of the first scale is larger than the radius of the second scale, and scales are provided on the first scale and the second scale; the first leg 8 and the second leg 4 are coaxially connected in the fixed connecting head through a rotating shaft 12, and the first leg 8 and the second leg 4 can swing around the rotating shaft; a window 2 is provided on the connecting plate on the side of the fixed connecting head, and scale pointers 11 are symmetrically provided on the upper and lower ends of the window to facilitate viewing and correction of the scales.

[0030] refer to Figure 3Furthermore, the thicknesses of the first scale 10, the second scale 3, the first leg 8, and the second leg 4 are consistent.

[0031] refer to Figure 2 or Figure 5 or Figure 6 or Figure 7 or Fig. 9 Furthermore, a first reinforcing rib 9 is provided between the first scale 10 and the first connecting head 14, and a second reinforcing rib 19 is provided between the second scale 3 and the second connecting head 16, and the connection strength and rigidity of the first scale and the second scale are ensured by setting the reinforcing ribs.

[0032] Furthermore, one end of the rotating shaft 12 has a positioning step and the other end has an external thread, which is fixed by a locking nut 1201. This structure is simple to set up and easy to adjust, and it is convenient to adjust the tightness.

[0033] refer to Fig.10 Furthermore, the outer movable sleeves of the first leg 8 and the second leg 4 are provided with a shell 18.

[0034] Furthermore, the compass body is made of plastic or wood.

[0035] Working principle: First, in order to ensure the accuracy and clarity of the scale, set the length of the compass legs unchanged and the length of the lead core and the positioning pin to be constant at 7mm. (Take the second leg as an example) Let the distance from the axis to the tip of the positioning pin be L, and the radius of the circle to be drawn be R. Take the central axis of the main body as the reference line, and the center of the leg rotation circle is on the central axis. Then the vertical distance from the tip of the positioning pin to the reference line is half of the radius of the circle drawn, which is calculated as R / 2. Let the angle between the second leg and the reference line be A. According to the sine theorem, we can get: R=2LsinA. When the leg length L is constant, how large the radius of the circle is needed, just substitute it into the formula to find out the size of A. When the deflection angle of one leg is A, the closing angle is 2A, and then the scale can be marked according to a certain method; the following table is the test data of the distance from the axis to the tip of the positioning pin;

[0036] R / 2 sI A R 5mm 0.0556 3.1873° 1cm 10mm 0.1111 6.3787° 2cm 15mm 0.1667 9.596° 3cm 20mm 0.2222 12.8383° 4cm 25mm 0.2778 16.1289° 5cm 30mm 0.3333 19.4692° 6cm 35mm 0.3889 22.8861° 7cm 40mm 0.4444 26.385° 8cm 45mm 0.5 30° 9cm 50mm 0.5556 33.7521° 10cm 55mm 0.6111 37.6691° 11cm 60mm 0.6667 41.8129° 12cm 65mm 0.7222 46.2364° 13cm

[0037] According to the table above, the most suitable data is when the distance from the axis to the tip of the positioning needle is 90mm.

[0038] refer to Fig.12, Scale marking method: (Take the right leg as an example) Using the characteristic of "equal vertical angles", extend the straight line between the tip of the positioning needle and the axis to the circular ruler to make the 0 scale line. Then take the angle A corresponding to R = 1cm, 2cm, ... 13cm, and use the vertical angle property to mark as accurately as possible on the right side of the 0 scale. The second scale is marked on the outer edge, and the first scale is marked on the inner edge; except for a few errors within 1mm due to marking errors, the radius corresponding to all other situations has an error within 0.2mm, or even 0.1mm or less, which basically meets most drawing tasks in learning and life.

[0039] The method of using the utility model (taking R=50mm as an example):

[0040] (1) Adjust the bolts properly before use to prevent them from loosening during drawing;

[0041] (2) Adjust the first leg first: Hold the pen tip with one hand and adjust the first leg with the other hand so that the mark "5" on the outer rail ruler is aligned with the upper pointer;

[0042] (3) Adjust the second leg: Hold the left leg with one hand and adjust the second leg with the other hand so that the mark "5" on the inner rail ruler is aligned with the lower pointer;

[0043] (4) Hold the handle on the fixed connector with one hand and make a circle with a radius of 50 mm.

[0044] The lead core and the positioning needle described in the utility model are existing products, and the placement positions can be switched left and right.

[0045] Based on the above description, those skilled in the art can make simple changes and modifications without departing from the technical concept of the present invention, which should fall within the protection scope of the present invention.

Claims

1. A double-track double-scale compass, comprising a fixed connector, a first leg, a second leg, and a positioning needle, wherein the first leg and the second leg are arranged in the fixed connector and are coaxially arranged, the positioning needle and the lead are respectively installed at the lower ends of the first leg and the second leg, and the lower ends of the first leg and the second leg are respectively provided with a core fixing cover for fixing the positioning needle and the lead; characterized in that: The upper end of the first leg is provided with a first arc-shaped scale and a first connector, a positioning groove is provided inside the first connector, and first connecting holes are provided on both side walls of the positioning groove; the upper end of the second leg is provided with a second arc-shaped scale and a second connector, and the second connector is provided with a second connecting hole; the first scale and the second scale are coaxial scales with different radii after installation, the radius of the first scale is greater than the radius of the second scale, and scales are provided on the first scale and the second scale; The first leg and the second leg are coaxially connected in the fixed connection head through a rotating shaft, and the first leg and the second leg can swing around the rotating shaft; A window is provided on the connecting plate on the side of the fixed connecting head, and scale pointers are symmetrically arranged at the upper and lower ends of the window to facilitate viewing and calibration of the scale.

2. A double-track double-scale compass according to claim 1, characterized in that: The thickness of the first scale and the second scale are consistent.

3. A double-track double-scale compass according to claim 1, characterized in that: A first reinforcing rib is provided between the first scale and the first connector, and a second reinforcing rib is provided between the second scale and the second connector.

4. A double-track double-scale compass according to claim 1, characterized in that: The core fixing cover is connected with the first leg and the second leg by threads, and a mounting groove is arranged at the center of the threads at the lower ends of the legs for mounting a positioning pin or a lead core.

5. A double-track double-scale compass according to any one of claims 1 to 4, characterized in that: One end of the rotating shaft is provided with a positioning step, and the other end is provided with an external thread, which is fixed by a locking nut.

6. A double-track double-scale compass according to claim 1, characterized in that: The outer movable sleeves of the first supporting leg and the second supporting leg are provided with shells.

7. A double-track double-scale compass according to claim 5, characterized in that: The outer movable sleeves of the first supporting leg and the second supporting leg are provided with shells.

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