Push rod type resistance adjusting mechanism with more stable contact state

Abstract

The utility model relates to a push rod type resistance adjusting mechanism with a more stable contact state, which comprises a switch base, a push rod connected to the base in a sliding mode, a reset spring arranged in the base and used for driving the push rod to reset, a sliding block connected to the base in a sliding mode and a resistance adjusting elastic piece fixedly connected to the sliding block. A partition plate is arranged on the base, located on one side of the push rod and parallel to the push rod, a long hole extending in the sliding direction of the push rod is formed in the partition plate, the sliding block is slidably connected into the long hole with the two long edges of the long hole as rails, and the resistance adjusting elastic piece is fixedly connected to the face, back to the push rod, of the sliding block. A contact pin of the resistance adjusting elastic piece abuts against a resistance adjusting carbon film on the PCB parallel to the partition plate, the push rod is provided with a connecting column which extends towards the long hole and is connected with the sliding block, and when the push rod axially moves in a reciprocating mode, the connecting column drives the sliding block to move in a reciprocating mode in the length direction of the long hole.

Description

Technical Field

[0001] This utility model belongs to the field of switch technology, specifically relating to a push rod type resistance adjustment mechanism with more stable contact state. Background Technology

[0002] Currently, potentiometer functions in power tool switches are typically achieved through a resistor in conjunction with a resistive element and a printed carbon film or multi-segment copper foil on a PCB. However, since the resistive element in current switches is usually mounted on the switch's push rod, pressing the push rod causes the resistive element to reciprocate along the push rod's axis, changing its position on the printed carbon film or multi-segment copper foil to alter the resistance value in the circuit and thus adjust the motor speed of the power tool.

[0003] However, because the switch push rod and the switch housing are in clearance fit, the direction in which the operator presses the push rod is random when using the switch. The push rod has a certain degree of freedom when it is pushed, and the adjusting spring installed on the push rod will also change with the direction of the push rod. This causes the sliding path of the adjusting spring on the printed carbon film or multi-segment copper foil to be inconsistent, affecting the contact state of the adjusting spring.

[0004] In addition, the push rod inside the switch will drive other mechanisms such as the moving contact group. At this time, the push rod will also be tilted due to the reaction force of these mechanisms, which will affect the contact state of the adjusting spring.

[0005] It is evident that the conventional structure in which the adjusting spring is directly connected to the push rod has the technical problem of unstable offset in multiple directions when the adjusting spring slides. This can lead to a decrease in the contact stability between the adjusting spring and the printed carbon film or multiple copper foil segments, or an instability in the resistance value of the circuit, thus affecting the output stability of the power tool. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a push rod type resistance adjustment mechanism with more stable contact state, and to solve the technical problem that the contact stability between the resistance adjustment spring and the printed carbon film or multi-segment copper foil is affected by the direction of push rod movement in conventional push rod type resistance adjustment mechanisms, which leads to a decrease in the contact stability between the resistance adjustment spring and the printed carbon film or multi-segment copper foil or an unstable resistance value in the circuit.

[0007] To solve the above technical problems, the technical solution adopted by the present utility model is as follows: A push rod type resistance adjusting mechanism with a more stable contact state, which includes a switch base, a push rod slidably connected to the base, and a return spring disposed in the base for driving the push rod to reset. It also includes a slider slidably connected to the base and a resistance adjusting elastic piece fixedly connected to the slider. A partition is provided on the base, the partition is located on one side of the push rod and is parallel to the push rod. A long hole extending along the sliding direction of the push rod is formed on the partition. The slider is slidably connected in the long hole with the two long sides of the long hole as tracks. The resistance adjusting elastic piece is fixedly connected to the side of the slider facing away from the push rod. The contact feet of the resistance adjusting elastic piece abut against the resistance adjusting carbon film on the PCB board parallel to the partition. A connecting column extending towards the long hole and connected to the slider is provided on the push rod. When the push rod moves axially back and forth, the connecting column drives the slider to move back and forth along the length direction of the long hole.

[0008] As a preferred solution, two parallel guiding grooves are provided on the side of the partition facing away from the push rod. The two guiding grooves are respectively arranged on the two side edges of the long hole and both extend along the long side of the long hole. The slider has a "Ji" - shaped structure, the middle part of which is embedded in the long hole, and the two outward - turned edges on both sides are respectively embedded in the two guiding grooves. The middle part of the resistance adjusting elastic piece is a connecting part. The two ends of the connecting part extending along the length direction of the long hole respectively extend out of the two ends of the slider to form contact feet. Each contact foot is bent and inclined towards the PCB board at the same angle. The elastic force between the resistance adjusting elastic piece and the PCB board drives the outward - turned edges on both sides of the slider to always remain in contact with the two guiding grooves. The connecting part is fixedly connected to the slider.

[0009] As a preferred solution, there are four connecting columns. The four connecting columns are respectively arranged in pairs at the front and rear ends of the sliding direction of the slider. The slider is clamped between the four connecting columns. The front and rear ends of the slider are flat end faces perpendicular to its sliding direction. Each connecting column can slide relative to the slider along the width direction of the long hole.

[0010] As a preferred solution, the slider is formed by bending a sheet. A plurality of clamping plates arranged in a matrix are formed on the slider by stamping. The connecting part of the resistance adjusting elastic piece is clamped between the clamping plates.

[0011] As a preferred solution, a blind hole extending axially is formed at one end of the push rod located in the base. A guiding column coaxial with the blind hole is fixedly provided on the inner wall of the base opposite to the blind hole. The return spring is sleeved on the guiding column, and both the guiding column and the return spring are inserted into the blind hole of the push rod.

[0012] The beneficial effects of this utility model are as follows: This utility model uses elongated holes to restrict the sliding direction of the slider, thereby reducing or eliminating the lateral offset of the adjusting spring when it slides along the PCB board. At the same time, the sliding connection between the elongated holes and the slider maintains the distance between the slider and the PCB board, ensuring a stable contact between the adjusting spring and the carbon film on the CPB board. By using the elongated holes to restrict the slider, the influence of unstable radial deviation during the axial sliding of the push rod on the contact stability between the adjusting spring and the carbon film or copper foil is effectively overcome, thereby improving the output stability of the switch and improving product quality. Attached Figure Description

[0013] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, wherein:

[0014] Figure 1 This is an exploded structural diagram of the present invention;

[0015] Figure 2 This is a schematic diagram of the specific assembly structure of the slider described in this utility model;

[0016] Figure 3 This is a schematic diagram of the specific connection structure between the connecting column and the slider described in this utility model;

[0017] Figure 4 This is a schematic diagram of the application structure of the push rod type resistance adjustment mechanism described in this utility model in a switch;

[0018] Figures 1-4 In the middle: 1. Base; 2. Push rod; 3. Return spring; 4. Slider; 4a. Outward flange; 5. Adjustable spring; 5a. Connecting part; 5b. Contact foot; 6. Partition; 7. Long hole; 8. Connecting post; 9. Guide post; 10. Guide groove; 11. Snap-on plate; 12. Blind hole; 13. PCB board; 14. Switch housing. Detailed Implementation

[0019] The specific implementation scheme of this utility model will now be described in detail with reference to the accompanying drawings.

[0020] like Figures 1-4A push-rod type resistance adjusting mechanism with a more stable contact state is shown, which includes a base 1 of the switch, a push rod 2 slidably connected to the base 1, and a return spring 3 arranged in the base 1 for driving the push rod 2 to reset. It also includes a slider 4 slidably connected to the base 1 and a resistance adjusting elastic sheet 5 fixedly connected to the slider 4. A partition plate 6 is arranged on the base 1. The partition plate 6 is located on one side of the push rod 2 and is parallel to the push rod 2. A long hole 7 extending along the sliding direction of the push rod 2 is formed on the partition plate 6. The slider 4 is slidably connected in the long hole 7 with the two long sides of the long hole as tracks. The resistance adjusting elastic sheet 5 is fixedly connected to the side of the slider 4 facing away from the push rod 2. The contact feet of the resistance adjusting elastic sheet 5 are abutted against the resistance adjusting carbon film on the PCB board parallel to the partition plate 6. A connecting column 8 extending towards the long hole 7 and connected to the slider 4 is arranged on the push rod 2. When the push rod 2 moves axially back and forth, the connecting column 8 drives the slider 4 to move back and forth along the length direction of the long hole 7.

[0021] The long hole 7 restricts the sliding direction of the slider 4, reducing or eliminating the left-right offset amount when the resistance adjusting elastic sheet 5 slides along the PCB board. At the same time, by using the sliding connection relationship between the long hole 7 and the slider 4, the distance between the slider 4 and the PCB board is kept unchanged, ensuring a stable contact relationship between the resistance adjusting elastic sheet 5 and the carbon film on the CPB board. By using the restriction of the long hole 7 on the slider 4, the influence of the unstable radial deviation existing when the push rod 2 slides axially on the contact stability between the resistance adjusting elastic sheet 5 and the carbon film or copper foil is effectively overcome, improving the output stability of the switch and the product quality.

[0022] In this embodiment, two mutually parallel guiding grooves 10 are arranged on the side of the partition plate 6 facing away from the push rod 2. The two guiding grooves 10 are respectively arranged on both side edges of the long hole 7 and both extend along the long sides of the long hole 7. The slider 4 has a "ji" - shaped structure. The middle part of it is embedded in the long hole 7, and the outer turned - up edges 4a on both sides are respectively embedded in the two guiding grooves 10. The middle part of the resistance adjusting elastic sheet 5 is a connecting part 5a. The two ends of the connecting part 5a along the length direction of the long hole respectively extend out beyond the two ends of the slider 4 to form contact feet 5b. Each contact foot 5b is bent and inclined towards the PCB board at the same angle. The elastic force between the resistance adjusting elastic sheet 5 and the PCB board drives the outer turned - up edges 4a on both sides of the slider 4 to always keep in contact with the two guiding grooves 10. The connecting part 5a is fixedly connected to the slider 4.

[0023] The guiding grooves 10 are used to further guide and position the outer turned - up edges 4a of the slider 4, effectively blocking the slider 4 from moving away from the PCB board, thereby further ensuring the distance between the slider 4 and the PCB board and ensuring the contact stability between the resistance adjusting elastic sheet 5 and the carbon film or copper foil.

[0024] In this embodiment, there are four connecting posts 8. The four connecting posts 8 are arranged in pairs at the front and rear ends of the slider 4 in the sliding direction. The slider 4 is engaged between the four connecting posts 8. The front and rear ends of the slider 4 are both straight end faces perpendicular to its sliding direction. Each connecting post 8 can slide relative to the slider 4 along the width direction of the elongated hole 7. This can improve the problem of the connecting post 8 causing the slider 4 to shift when it shifts along the width direction of the elongated hole 7.

[0025] In practical applications, the number of connecting posts 8 is not fixed. Users can increase or decrease the number of connecting posts 8 and the specific connection method with the slider 4 according to actual needs, such as snap-fit, riveting, plug-in, welding, etc.

[0026] In this embodiment, the slider 4 is preferably formed by bending a sheet, and multiple matrix-arranged snap-fit ​​plates 11 are formed on the slider 4 by stamping. The connecting part 5a of the damping spring 5 is snapped between each snap-fit ​​plate 11. Such a slider structure is simple, has low manufacturing cost, is structurally stable, and has high reliability.

[0027] The push rod 2 has an axially extending blind hole 12 at one end inside the base 1. A guide post 9 coaxial with the blind hole 12 is fixedly installed on the inner wall of the base 1 opposite to the blind hole 12. The reset spring 3 is sleeved on the guide post 9. Both the guide post 9 and the reset spring 3 are inserted into the blind hole 12 of the push rod 2.

[0028] Since the partition plate 6 has an elongated hole, it cannot effectively guide the push rod 2. In this embodiment, the guide post 9 is directly inserted into the blind hole of the push rod 2, which can effectively improve the stability of the axial movement of the push rod 2 and reduce its radial offset.

[0029] The working process of this utility model is as follows: combining Figures 1-4 First, the push rod type resistance adjustment mechanism described in this embodiment is arranged as follows: Figure 4As shown, the assembly is performed so that the adjusting spring 5 abuts against the carbon film on the PCB board 13 to maintain contact. Finally, the switch housing 14 is closed to maintain the positional relationship between the PCB board 13 and the base 1, thereby keeping the contact relationship between the adjusting spring 5 and the carbon film on the PCB board 13 constant. When using the switch, the user adjusts the output signal strength of the switch by pressing the push rod 2. At the same time as pressing the push rod 2, the connecting post 8 on the push rod 2 drives the slider 4 to slide along the elongated hole 7. The slider 4 drives the individual contacts 5b of the adjusting spring 5 to slide on the carbon film, thereby changing the resistance value of the carbon film connected to the circuit and changing the output signal strength of the switch. When the end of the push rod 2 inside the switch moves away from the slider 4 due to force, the connecting post 8 will move a certain distance away from the slider 4, but will not disengage from the slider 4. The outer flange 4a of the slider 4, blocked by the guide groove 10 on the partition 6, maintains a constant distance from the PCB board 13, thereby ensuring that the contact relationship between the adjusting spring 5 and the carbon film on the PCB board 13 remains unchanged. When the push rod 2 is located inside the switch and is offset along the width of the elongated hole 7 due to the force, the connecting post 8 can also slide in the opposite direction relative to the slider 4 along the width of the elongated hole 7. At the same time, the slider 4 is limited by the elongated hole 7 and keeps its sliding direction from shifting, thereby stabilizing the resistance value of the carbon film connected to the circuit, improving the output stability of the switch, and improving the quality of the switch.

[0030] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some examples of its application, and are not intended to limit the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention.

Claims

1. A push-rod type resistance adjustment mechanism with more stable contact state, comprising a switch base (1), a push rod (2) slidably connected to the base (1), and a reset spring (3) disposed in the base (1) for driving the push rod (2) to reset, characterized in that, It further includes a slider (4) slidably connected to the base (1) and a variable resistor elastic sheet (5) fixedly connected to the slider (4). A partition plate (6) is provided on the base (1). The partition plate (6) is located on one side of the push rod (2) and is parallel to the push rod (2). A long hole (7) extending along the sliding direction of the push rod (2) is formed on the partition plate (6). The slider (4) is slidably connected in the long hole (7) with the two long sides of the long hole as tracks. The variable resistor elastic sheet (5) is fixedly connected to the side of the slider (4) facing away from the push rod (2). The contact feet of the variable resistor elastic sheet (5) are in contact with the variable resistor carbon film on the PCB board parallel to the partition plate (6). A connecting column (8) extending towards the long hole (7) and connected to the slider (4) is provided on the push rod (2). When the push rod (2) moves axially back and forth, the connecting column (8) drives the slider (4) to move back and forth along the length direction of the long hole (7).

2. The push-rod type resistance adjustment mechanism according to claim 1, characterized in that, On the side of the partition plate (6) facing away from the push rod (2), two mutually parallel guiding grooves (10) are provided. The two guiding grooves (10) are respectively arranged on both side edges of the long hole (7) and both extend along the long side of the long hole (7). The slider (4) has a "U" - shaped structure. The middle part of it is embedded in the long hole (7), and the outward - turned edges (4a) on both sides are respectively embedded in the two guiding grooves (10). The middle part of the variable resistor elastic sheet (5) is a connecting part (5a). The two ends of the connecting part (5a) along the length direction of the long hole respectively extend outwards beyond the two ends of the slider (4) to form contact feet (5b). Each contact foot (5b) is bent and inclined towards the PCB board at the same angle. The elastic force between the variable resistor elastic sheet (5) and the PCB board drives the outward - turned edges (4a) on both sides of the slider (4) to always keep in contact with the two guiding grooves (10). The connecting part (5a) is fixedly connected to the slider (4).

3. The push-rod type resistance adjustment mechanism according to claim 2, characterized in that, There are four connecting columns (8). The four connecting columns are divided into two pairs and are respectively arranged at the front and rear ends in the sliding direction of the slider. The slider is clamped between the four connecting columns. Both the front and rear ends of the slider are flat end faces perpendicular to its sliding direction. Each connecting column can slide relative to the slider along the width direction of the long hole.

4. The push-rod type resistance adjustment mechanism according to claim 2, characterized in that, The slider (4) is formed by bending a plate. A plurality of card - connecting plates (11) arranged in a matrix are formed on the slider (4) by stamping. The connecting part (5a) of the variable resistor elastic sheet (5) is clamped between the card - connecting plates (11).

5. The push-rod type resistance adjustment mechanism according to claim 1, characterized in that, At one end of the push rod (2) located inside the base (1), a blind hole (12) extending axially is formed. On the inner wall of the base (1) opposite to the blind hole (12), a guiding column (9) coaxial with the blind hole (12) is fixedly provided. The return spring (3) is sleeved on the guiding column (9), and both the guiding column (9) and the return spring (3) are inserted into the blind hole (12) of the push rod (2).

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