An electronic stylus with a pressure sensing structure and an overload protection function

Abstract

The present invention provides an electronic stylus with a pressure sensing structure and an overload protection function, including a pen barrel. A main board fixing frame is arranged inside the pen barrel, a metal core rod is arranged inside the main board fixing frame, a rubber sleeve is arranged at one end of the metal core rod, a metal tube is also arranged on the metal core rod, the metal tube is sleeved on the metal core rod, an elastic member is arranged at the other end of the metal core rod, the elastic member is also connected with a top block, and a limiting bump for fixing the top block is also arranged inside the metal tube. The electronic stylus with a pressure sensing structure and an overload protection function provided by the present invention has the advantages of reasonable structural design, convenient use, etc., and has a long service life and great economic value.

Description

Technical Field

[0001] The present invention relates to the technical field of pen design, and in particular, to an electronic touch pen with a pressure sensing structure and an overload protection function. Background Art

[0002] A pressure-sensitive pen refers to a digital pressure-sensing pen used for drawing, generally used in conjunction with a graphics tablet. Currently, there are two types: an active pressure-sensitive pen that requires a battery and a passive pressure-sensitive pen that relies on the graphics tablet to provide wireless power. In the prior art, the pressure-sensitive pen tip is fixedly connected to the pressure-sensitive element, the spring is pre-compressed between the pen tip and the front end cap, the front end cap is fixedly connected to the module bracket with glue, and the contact spring, the contact head, the pressure-sensitive element and its components, the contact steel sheet, and the silicone rubber ring are enclosed in a cylinder to form a pressure transmission mechanism module, and the housing is fixedly connected to the module with glue. The positive pressure received by the contact head causes the contact point of the pressure-sensitive element to press against the steel sheet, and the steel sheet compresses the silicone rubber ring, that is, the pressure received by the contact head compresses the silicone rubber ring, and the contact head moves inward under the action of the pressure. In this process, the pressure-sensitive element senses the pressure. The main disadvantages of the prior art solutions

[0003] a. There are shaft-hole fits between the contact head and the housing, the front end cap, and the module bracket respectively, which easily generate additional frictional resistance, resulting in the positive pressure received by the contact head not being transmitted to the pressure-sensitive element;

[0004] b. The flexible FPC will exert a pressure or a tensile force on the pressure-sensitive element and its components (for different products, or for the same product at different times, this force is uncertain), resulting in the positive pressure received by the contact head not being accurately transmitted to the pressure-sensitive element;

[0005] c. The contact steel sheet is too thin. After tilting: it can neither accurately transmit the pressure of the contact head nor will it generate a lateral force on the pressure-sensitive element to damage the pressure-sensitive element. Moreover, after the contact steel sheet tilts, the silicone rubber ring will not rebound in place (skew), causing the pre-pressure received by the pressure-sensitive element to change and unable to correctly sense the pressure transmitted by the contact head;

[0006] d. The compression amount of the silicone rubber ring is too small to limit the stroke of the contact head, resulting in damage to the pressure-sensitive element under a large pressure. (Because the positive pressure on the contact head will compress the silicone rubber ring, and the maximum working pressure of the pressure-sensitive element may have compressed the silicone rubber ring to the limit, so the stroke of the contact head cannot be limited. Therefore, further improvement is needed. Summary of the Invention

[0007] The present invention provides an electronic touch pen with a pressure sensing structure and an overload protection function, which has a reasonable structural design and is convenient to use, aiming at the above-mentioned deficiencies of the prior art.

[0008] The technical solution adopted by the present invention to solve the above problems is as follows:

[0009] The present invention provides an electronic stylus with a pressure sensing structure and an overload protection function, including a pen barrel. A main board fixing frame is arranged inside the pen barrel. A metal core rod is arranged inside the main board fixing frame. One end of the metal core rod is provided with a rubber sleeve. A metal tube is also arranged on the metal core rod. The metal tube is sleeved on the metal core rod. An elastic member is arranged at the other end of the metal core rod. The elastic member is also connected with a top block. The metal tube is internally provided with a limiting bump for fixing the top block. A pre-pressure spring and a first metal contact piece are sleeved outside the top block. The top block is connected with a second metal contact piece. The second metal contact piece is connected with a plastic isolation piece. A magnet is arranged inside the plastic isolation piece. The magnet contacts a pressure sensor. The pressure sensor is arranged on the main board.

[0010] Further, a core rod slot is arranged on the metal core rod. A clamping body matched with the core rod slot is arranged on the rubber sleeve.

[0011] Further, a top block slot is arranged on the top block for combining with the limiting bump. A blocking body is also arranged on the top block. The blocking body is arranged outside the metal tube.

[0012] Further, the elastic member is an overload spring.

[0013] Further, a core rod convex block is also arranged on the metal core rod. A free stroke L1 is formed between the core rod convex block and the metal tube.

[0014] Further, a free stroke L2 exists between the blocking body and the metal tube.

[0015] The beneficial effects obtained by the present invention are as follows:

[0016] The electronic stylus with a pressure sensing structure and an overload protection function provided by the present invention has the advantages of reasonable structural design and convenient use, making the pressure-signal change curve of the pressure sensor more sensitive; moreover, the contact point of this pressure sensor is extremely small (for example, the area of the pressure contact surface is below 0.05 mm²). High pressure will crush the contact steel sheet. The crushed steel sheet wraps the contact point of the pressure-sensitive element, which will generate a lateral force on the pressure-sensitive element, and the lateral force will easily damage the pressure-sensitive element. Therefore, this solution realizes that under any conditions, the pressure-sensitive element will definitely not be subjected to a large pressure, has a long service life and great economic value. Description of the Drawings

[0017] Figure 1 is a cross-sectional view of an electronic stylus with a pressure sensing structure and an overload protection function according to the present invention;

[0018] Figure 2It is another cross-sectional view of an electronic stylus with a pressure-sensitive structure and an overload protection function according to the present invention;

[0019] Figure 3 It is a partial structural view of an electronic stylus with a pressure-sensitive structure and an overload protection function according to the present invention;

[0020] Figure 4 It is a partial exploded view of an electronic stylus with a pressure-sensitive structure and an overload protection function according to the present invention. Detailed implementation manners

[0021] The following specifically illustrates the implementation manners of the present invention in conjunction with the accompanying drawings. The accompanying drawings are only for reference and illustration, and do not constitute a limitation on the protection scope of the present invention patent.

[0022] As Figures 1-4 shown, the present invention provides an electronic stylus with a pressure-sensitive structure and an overload protection function, including a pen barrel 1. A main board fixing frame 2 is arranged inside the pen barrel 1. A metal core rod 3 is arranged inside the main board fixing frame 2. One end of the metal core rod 3 is provided with a rubber sleeve 4. A metal tube 5 is also arranged on the metal core rod 3. The metal tube 5 is sleeved on the metal core rod 3. The other end of the metal core rod 3 is provided with an elastic member 6. The elastic member 6 is also connected with a top block 7. A limiting bump 51 for fixing the top block 7 is arranged inside the metal tube 5. A pre-pressure spring 8 and a first metal contact piece 9 are sleeved outside the top block 7. The top block 7 is connected with a second metal contact piece 10. The second metal contact piece 10 is connected with a plastic isolation sheet 11. A magnet 12 is arranged inside the plastic isolation sheet 11. The magnet 12 contacts a pressure sensor 13. The pressure sensor 13 is arranged on a main board 14.

[0023] In this embodiment, a core rod card slot 31 is arranged on the metal core rod 3. A card body 41 matched with the core rod card slot 31 is arranged on the rubber sleeve 4.

[0024] In this embodiment, a top block card slot 71 is arranged on the top block 7 for combining with the limiting bump 51. A blocking body 72 is also arranged on the top block 7. The blocking body 72 is arranged outside the metal tube 5.

[0025] In this embodiment, the elastic member 6 is an overload spring.

[0026] In this embodiment, a core rod convex block 32 is also arranged on the metal core rod 3. A free stroke L1 is formed between the core rod convex block 32 and the metal tube 5.

[0027] In this embodiment, a free stroke L2 exists between the blocking body 72 and the metal tube 5.

[0028] In this embodiment: The nib assembly (including the rubber sleeve, metal core rod, and metal tube) is in a sliding fit with the main board bracket through a shaft and hole; the magnet assembly (including the plastic spacer and magnet) is in a sliding fit with the main board bracket; the inner hole of the main board bracket has good coaxiality; and the frictional resistance is minimized as much as possible.

[0029] The ball head of the top block contacts the plane of the second metal contact. When the nib is laterally pressed, the magnet assembly will not be affected by the lateral force; nor will the pressure sensor be affected by the lateral force. (The pressure sensor is easily damaged by the lateral force)

[0030] Analyze the problem based on the situation where the nib is subjected to an axial pressure. The frictional resistance can be almost ignored, as follows:

[0031] Accurately transmit the pressure:

[0032] a When the nib assembly is subjected to a pressure less than F2, the nib assembly will not move, and the pressure will be accurately transmitted to the pressure sensor.

[0033] b When the nib assembly is subjected to a pressure greater than F2, the nib assembly compresses the overload spring, and the top block does not move, and the pressure is accurately transmitted to the pressure sensor.

[0034] c When the nib moves a stroke of L1 under the action of pressure, the nib assembly is limited by the main board bracket and cannot move downward anymore. At this time, the compression pressure of the overload spring is F3, and the pressure received by the pressure sensor is also F3. Under various assembly errors, it is set that L2 is greater than L1.

[0035] 2.2.3 Protection of the pressure-sensitive element:

[0036] d When the nib assembly is subjected to a pressure greater than F3, the nib assembly has been limited by the main board bracket. At this time, the compression pressure of the overload spring is F3, and the pressure received by the pressure sensor is F3 + F1. F3 + F1 is the overload protection pressure of the pressure sensor.

[0037] When the nib is subjected to a lateral pressure, the frictional force f1 between the upper part of the nib and the main board bracket is increased. Assume that when the nib is subjected to a lateral pressure, its axial component force is Fz, the frictional force between the nib assembly and the main board bracket is f1, and the frictional force between the nib assembly and the top block is f2. Then the force received by the pressure sensor is Fz + F1 - f1. The overload protection pressure of the pressure sensor is F3 + F1 + f2 - f1.

[0038] An electronic touch pen with a pressure sensing structure and an overload protection function provided by the present invention has the advantages of reasonable structural design and convenient use, making the pressure-signal change curve of the pressure sensor more sensitive; moreover, the contact point of the pressure sensor is extremely small (for example, the area of the pressure contact surface is below 0.05 mm^2), and high pressure will crush the contact steel sheet. The crushed steel sheet wraps the contact point of the pressure-sensitive element, which will exert a lateral force on the pressure-sensitive element, and the lateral force will easily damage the pressure-sensitive element. Therefore, this solution realizes that under any conditions, the pressure-sensitive element will definitely not be subjected to a large pressure, has a long service life and great economic value.

[0039] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. An electronic stylus with a pressure sensing structure and an overload protection function, including a pen barrel, characterized in that: A main board fixing bracket is arranged inside the pen container. A metal core rod is arranged inside the main board fixing bracket. One end of the metal core rod is provided with a rubber sleeve. A metal tube is also arranged on the metal core rod. The metal tube is sleeved on the metal core rod. An elastic member is arranged at the other end of the metal core rod. The elastic member is also connected with a top block. A limiting bump for fixing the top block is arranged inside the metal tube. A pre-pressure spring and a first metal contact are sleeved outside the top block. The top block is connected with a second metal contact. The second metal contact is connected with a plastic isolation sheet. A magnet is arranged inside the plastic isolation sheet. The magnet contacts a pressure sensor. The pressure sensor is arranged on the main board. A core rod slot is arranged on the metal core rod. A clamping body matched with the core rod slot is arranged on the rubber sleeve. A top block slot is arranged on the top block for combining with the limiting bump. A blocking body is also arranged on the top block. The blocking body is arranged outside the metal tube. The elastic member is an overload spring. A core rod convex block is also arranged on the metal core rod. A free stroke L1 is formed between the core rod convex block and the metal tube. A free stroke L2 exists between the blocking body and the metal tube.

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