Long-life resistance-adjusting film strip applied to speed-adjusting switch circuit board

Abstract

The utility model relates to a long-life resistance-adjusting film strip applied to a speed-adjusting switch circuit board, which comprises a carbon film strip body printed on a printed circuit board (PCB), and further comprises metal zebra strips printed on the PCB and sequentially arranged in parallel at equal intervals along the length direction of the carbon film strip body, one end of each zebra strip close to the carbon film strip body is electrically connected with the carbon film strip body, and the other end of each zebra strip is electrically connected with the speed-adjusting switch circuit board. The zebra strip is used for being in contact with an electric brush or a speed regulation reed, and one end of the carbon film strip body is conducted with a control circuit. The zebra strip is arranged on one side of the carbon film strip body, and the zebra strip is in sliding contact with an electric brush or a reed, so that direct sliding friction between the electric brush and the carbon film strip body is avoided, the carbon film strip is prevented from being abraded, the service life of the carbon film strip body is effectively prolonged, and resistance change of the carbon film strip body caused by abrasion of the carbon film strip body is avoided; and long-term stability of speed regulation precision is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of circuit boards, and in particular relates to a long-life resistance-adjusting film strip applied to a speed regulating switch circuit board. Background Art

[0002] Speed ​​control switches are widely used in power tools. Speed ​​regulation is achieved primarily by adjusting the resistance of a carbon film strip on the switch's circuit board. This is achieved by sliding a brush or reed against the strip, adjusting the length of the strip connected to the circuit and, consequently, the current flowing through the circuit. However, the carbon film strip itself is relatively weak and easily wears out from prolonged friction with the brush or reed, resulting in abnormal resistance and affecting speed regulation accuracy. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a long-life resistance-adjusting film strip applied to a speed-adjusting switch circuit board, so as to solve the technical problem that the resistance value of a traditional carbon film strip changes due to wear and tear, and the speed-adjusting accuracy decreases.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: a long-life resistance-adjusting film strip applied to a speed control switch circuit board, comprising a carbon film strip body printed on a PCB board, characterized in that it also comprises metal zebra strips printed on the PCB board and arranged in parallel at equal intervals along the length direction of the carbon film strip body, all zebra strips are electrically connected to the carbon film strip body at one end close to the carbon film strip body, the zebra strips are used to contact a brush or a speed control reed, and one end of the carbon film strip body is connected to the control circuit.

[0005] As a preferred solution, the zebra strips extend to the central axis of the carbon film strip body, and the carbon film strip body covers the zebra strips.

[0006] As a preferred solution, the zebra strips are tilted, and the tilt angle thereof satisfies that the brush or the speed regulating reed is always in contact with at least one zebra strip when moving along the length direction of the carbon film strip body.

[0007] As a preferred solution, the zebra strip is inclined 15-40 degrees relative to the length direction of the carbon film strip body.

[0008] The beneficial effects of the present invention are as follows: the present invention arranges a zebra strip on one side of the carbon film strip body, and utilizes the zebra strip to slide in contact with the brush or reed, thereby avoiding direct sliding friction between the brush and the carbon film strip body, avoiding wear of the carbon film strip, effectively extending the service life of the carbon film strip body, avoiding changes in the resistance of the carbon film strip body due to wear of the carbon film strip body, and ensuring long-term stability of the speed regulation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The utility model discloses a long -life resistance regulating membrane strip applied to the speed regulating switch circuit board, which belongs to the technical field of the resistance regulating membrane strip.

[0010] Figure 1 It is the structure diagram of long -life resistance regulating membrane strip that the utility model discloses.

[0011] Figure 1 In it: 1, membrane strip body;2, zebra strip. Specific implementation

[0012] The utility model discloses a long -life resistance regulating membrane strip applied to the speed regulating switch circuit board, which belongs to the technical field of the resistance regulating membrane strip.

[0013] As Figure 1 The utility model discloses a long -life resistance regulating membrane strip applied to the speed regulating switch circuit board, which belongs to the technical field of the resistance regulating membrane strip, including the carbon membrane strip body 1 printed on the PCB board, still include the metal zebra strip 2 printed on the PCB board and the length direction of carbon membrane strip body 1 is arranged in parallel with equal interval in proper order, all zebra strip 2 is close to the one end of carbon membrane strip body 1 and is electrically connected with carbon membrane strip body 1, zebra strip 2 is used for contacting with electric brush or speed regulating spring blade, and one end of carbon membrane strip body 1 is connected with control circuit conduction.

[0014] In the embodiment, in order to ensure the connection reliability of zebra strip 2 and carbon membrane strip body 1, preferably, zebra strip 2 extends to the central axis of carbon membrane strip body 1, and carbon membrane strip body 1 covers zebra strip 2.

[0015] The zebra strip 2 in the embodiment is arranged obliquely, and the oblique angle satisfies that the electric brush or the speed regulating spring blade is always in contact with at least one zebra strip 2 when moving along the length direction of the carbon membrane strip body 1, so that the circuit is kept in a conduction state.

[0016] The zebra strip 2 is inclined at an angle of 15-40° with respect to the length direction of the carbon membrane strip body 1.

[0017] The utility model discloses a long -life resistance regulating membrane strip applied to the speed regulating switch circuit board, which belongs to the technical field of the resistance regulating membrane strip. Figure 1 As The utility model discloses a long -life resistance regulating membrane strip applied to the speed regulating switch circuit board, which belongs to the technical field of the resistance regulating membrane strip, including the carbon membrane strip body 1 printed on the PCB board, still include the metal zebra strip 2 printed on the PCB board and the length direction of carbon membrane strip body 1 is arranged in parallel with equal interval in proper order, all zebra strip 2 is close to the one end of carbon membrane strip body 1 and is electrically connected with carbon membrane strip body 1, zebra strip 2 is used for contacting with electric brush or speed regulating spring blade, and one end of carbon membrane strip body 1 is connected with control circuit conduction.

[0018] The above embodiments only illustrate the principles and effects of the present application, and some applied embodiments, but are not intended to limit the present application; it should be noted that, for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A long-life resistance regulating film strip applied to a speed regulating switch circuit board, comprising a carbon film strip body printed on a PCB board, characterized in that, It also comprises metal zebra strips printed on the PCB board and arranged in parallel with equal intervals along the length direction of the carbon film strip body, all the zebra strips are electrically connected with the carbon film strip body near one end of the carbon film strip body, the zebra strips are used to contact with the brush or the speed regulating spring sheet, and one end of the carbon film strip body is in conduction with the control circuit.

2. The long-life resistive membrane strip according to claim 1, characterized in that, The zebra strips extend to the central axis of the carbon film strip body, and the carbon film strip body covers the zebra strips.

3. The long-life resistive membrane strip of claim 1, wherein, The zebra strips are arranged in an inclined manner, and the inclination angle satisfies that the brush or the speed regulating spring sheet is always in contact with at least one zebra strip when moving along the length direction of the carbon film strip body.

4. The long-life resistive membrane strip of claim 1, wherein, The inclination angle of the zebra strips relative to the length direction of the carbon film strip body is 15-40°.

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