Electrical switch unit for electrical device

Abstract

To provide an electrical switch unit for an electrical device such as an electrical device and a garden tool.SOLUTION: Disclosed is an electrical switch unit for an electrical device, including a case and a signaling module. The case accommodates an actuator 320 movably installed in the case. The signaling module comprises a circuit board 120 including a first region provided with a variable resistor element, the variable resistor element having a contact surface of the variable resistor element; and movement means operably connected to the actuator 320 and capable of bringing a conducting layer of a first film contact surface into contact with the contact surface of the variable resistor element in a plurality of contact point structures, in which an effective resistance of the variable resistor element is structured to vary in response to contacting the conductive layer of the first film contact surface with the contact surface of the variable resistor element at each of the plurality of contact point structures.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] The present invention relates to an electrical switch unit for electrical equipment such as electrical appliances, garden tools and the like. [Background technology]

[0002] Electrical devices, such as power tools and electric garden tools, convert input DC electrical power into mechanical power in the form of output torque or motion with a brushed or brushless DC motor. Typically, the electrical device includes a variable speed trigger mechanism, electrical switch contacts responsive to movement of an actuator in the variable speed trigger mechanism for selectively connecting and disconnecting DC power to the DC motor, motor signaling circuitry responsive to movement of the actuator for transmitting electrical signals indicative of a required DC motor speed, and a motor control circuit including power switching elements for selectively activating inputs to the stator windings of the DC motor in response to signals received from the motor signaling circuitry to thereby operate the DC motor at the required speed.

[0003] In electrical equipment, speed control is typically achieved by a potentiometer or similar device, which includes a variable resistor, e.g., a thin carbon film, mounted on a printed circuit board. For example, the effective resistance of the thin carbon film can be changed by sliding a conductive slider of the potentiometer across the surface of the thin carbon film in response to actuator movement. The variable voltage measured across the variable resistor can be used to indicate actuator movement and as a basis for controlling the speed of the electric motor. Repeated sliding of the conductive slider across the thin carbon film can significantly wear both the thin carbon film and the conductive slider, potentially resulting in inaccurate and unstable speed control operation. Furthermore, the thin carbon film is typically exposed to contaminant particles, which not only tend to short out the wiring in the conductive slider but can also exacerbate damage caused by the conductive slider wiping along the thin carbon film.

[0004] The applicant's U.S. Patent No. US10547257B2 discloses a variable speed controller for electrical equipment, in which the presence of a film between a variable resistor element and a slider contributes to reducing wear between the contact surface of the variable resistor element and the slider, since they are not in direct physical contact. Therefore, compared with conventional types of variable speed controllers, the reliability and stability of the operation of the variable speed controller can be maintained for a longer duration of use. Furthermore, the presence of the film also prevents contaminants from unintentionally shorting the wiring of the contact surface of the variable resistor element, thereby reducing unstable or inaccurate operation of the variable speed controller.

[0005] The contact surface of the variable resistor element in the patent includes a first region and a second region, and the first region and the second region are arranged in at least one of a series-connected or parallel-connected structure with respect to each other. By selectively electrically bridging different wirings in the first region to the conductive layer of the second region, it is necessary to selectively apply a variable voltage to the input pin of the integrated circuit chip, thereby changing the speed of the motor. However, since the wirings in the first region and the conductive layer of the second region are arranged in parallel on the same plane, this method requires a relatively large space and the cost of materials is relatively high. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to alleviate at least one of the above problems. [Means for solving the problem]

[0007] The present invention relates to several aspects. Embodiments of the present invention may include one or any combination of the various aspects described herein.

[0008] In a first aspect, the present invention provides an electric switch unit for an electric device used to control operation of a DC motor of the electric device, the electric switch unit comprising: a case housing an actuator movably mounted in the case, the actuator structure being adapted to be responsive to operation of a finger operable trigger, the actuator structure being adapted to be movable along an axis of movement from an OFF position in a direction towards an interior of an opening in the case towards an ON position, and to be movable along the axis of movement from the ON position in a direction towards an exterior of the opening in the case towards the OFF position; and a signaling module associated with the electric switch unit and including signaling circuitry, the signaling module being adapted to sense movement of the actuator and to output a signaling module signal indicative of the sensed movement or position of the actuator, the signaling module The module includes a circuit board including a first region having a variable resistor element with a contact surface of the variable resistor element; a membrane including a first membrane contact surface and a second membrane contact surface, the first membrane contact surface of the membrane having a first conductive layer, the first conductive layer of the first membrane contact surface separated from the contact surface of the variable resistor element by a spacing element, thereby forming a space between the two, one end of the first conductive layer of the first membrane contact surface electrically connected to the circuit board; and a moving means operably connected to an actuator, the moving means configured to move relative to the second membrane contact surface of the membrane in response to movement of the actuator to bring the first conductive layer of the first membrane contact surface into contact with the contact surface of the variable resistor element at a plurality of contact point structures, whereby the effective resistance of the variable resistor element changes in response to contacting the first conductive layer of the first membrane contact surface with the contact surface of the variable resistor element at each of the plurality of contact point structures.

[0009] Preferably, the variable resistor element is accessed by adopting a continuous variable resistor or a method in which a plurality of constant resistors are connected in series.

[0010] Preferably, exhaust holes are provided through the upper and lower surfaces of the circuit board at positions corresponding to the spaces in the circuit board.

[0011] Preferably, one end of the first conductive layer of the first membrane contact surface is in contact with and connected to a circuit board.

[0012] Preferably, a contact spring is arranged at one end of the second membrane contact surface corresponding to the first conductive layer of the first membrane contact surface, and the pressure of the contact spring can cause one end of the first conductive layer of the first membrane contact surface to contact and connect with the circuit board.

[0013] Also preferably, one end of the first conductive layer of the first membrane contact surface is adhered to the circuit board by a conductive adhesive layer.

[0014] Preferably, the electrical switch unit further includes a pair of electrical switch contacts, at least one of which is operably connected to the actuator, the pair of electrical switch contacts being arranged in a configuration in which they close in response to movement of the actuator along the axis of movement from an OFF position toward an ON position, so that power can be supplied from the DC power source to the DC motor via the pair of electrical switch contacts, and the pair of electrical switch contacts being arranged in a configuration in which they open in response to movement of the actuator along the axis of movement from the ON position toward the OFF position, so that power cannot be supplied from the DC power source to the DC motor via the pair of electrical switch contacts; a power module including at least one solid-state power switching element for controllably supplying power from the DC power source to the DC motor; and a control module including a control circuit for receiving signaling module signals and outputting control module signals in response to the received signaling module signals to control the at least one solid-state power switching element of the power module, the at least one solid-state power switching element controllably supplying power from the DC power source to the DC motor to allow the DC motor to operate at a speed corresponding to the sensed movement or position of the actuator.

[0015] In another aspect, the present invention provides an electric switch unit for an electric device used to control operation of a DC motor of the electric device, the electric switch unit comprising: a case accommodating an actuator movably mounted in the case, the actuator being configured to respond to operation of a trigger operable by a finger, the actuator being movable along an axis of movement from an OFF position toward an ON position in a direction toward the interior of an opening in the case, and being movable along the axis of movement from the ON position toward the exterior of the opening in the case toward the OFF position; and a signaling module associated with the electric switch unit and including a signaling circuit, the signaling module being configured to sense movement of the actuator and output a signaling module signal indicative of the sensed movement or position of the actuator, the signaling module being a circuit board including a first region having a variable resistor element and a second region having a signal control element, the first region and the second region being physically separated and partitioned. a circuit board having a variable resistor element contact surface and a signal control element contact surface; a film including a first film contact surface and a second film contact surface, the first film contact surface of the film having a first conductive layer and a second conductive layer, the first conductive layer and the second conductive layer of the first film contact surface being separated from the contact surface of the variable resistor element and the contact surface of the signal control element by a spacing element, thereby forming a space between them; and a film having one end of the first conductive layer and one end of the second conductive layer of the first film contact surface electrically connected to the circuit board, a moving means operably connected to the actuator, the moving means configured to move relative to the membrane second membrane contact surface in response to movement of the actuator and to bring a first conductive layer of the first membrane contact surface into contact with a contact surface of the variable resistor element at a plurality of contact point structures, whereby an effective resistance of the variable resistor element is changed in response to bringing the first conductive layer of the first membrane contact surface into contact with the contact surface of the variable resistor element at each of the plurality of contact point structures, in response to the moving means moving along the membrane second membrane contact surface;The second conductive layer of the first membrane contact surface can be contacted to the contact surface of the signal control element at a plurality of contact point structures, whereby the effective resistance of the signal control element is configured to change in response to contacting the second conductive layer of the first membrane contact surface to the contact surface of the signal control element at each of the plurality of contact point structures, or the circuitry of the signal control element is configured to switch a signal in response to contacting the second conductive layer of the first membrane contact surface to the contact surface of the signal control element at one of the plurality of contact point structures.

[0016] Preferably, the variable resistor element is accessed by adopting a continuous variable resistor or a method in which a plurality of constant resistors are connected in series.

[0017] Preferably, the signal control element is accessed by using a continuously variable resistor or a plurality of constant resistors connected in series, or by using an NC / NO switching circuit.

[0018] Preferably, the moving means is a rolling element, the rolling element including a first rolling portion and a second rolling portion, the first rolling portion being configured to be used to contact the first conductive layer with the contact surface of the variable resistor element, and the second rolling portion being configured to be used to contact the second conductive layer with the contact surface of the signal control element.

[0019] Preferably, exhaust holes are provided through the upper and lower surfaces of the circuit board at positions corresponding to the spaces in the circuit board.

[0020] Preferably, one end of the first conductive layer and one end of the second conductive layer of the first membrane contact surface are in contact with and connected to a circuit board.

[0021] Typically, contact springs are arranged at one end of the second membrane contact surface corresponding to the first conductive layer and the second conductive layer of the first membrane contact surface, and the pressure of the contact springs allows one end of the first conductive layer and the second conductive layer of the first membrane contact surface to contact and connect to the circuit board, respectively.

[0022] Preferably, one end of each of the first conductive layer and the second conductive layer on the first membrane contact surface is adhered to the circuit board by a conductive adhesive layer.

[0023] Preferably, the electrical switch unit further includes a pair of electrical switch contacts, at least one of which is operably connected to the actuator, the pair of electrical switch contacts being arranged in a configuration in which they close in response to movement of the actuator along the axis of movement from an OFF position toward an ON position, so that power can be supplied from the DC power source to the DC motor via the pair of electrical switch contacts, and the pair of electrical switch contacts being arranged in a configuration in which they open in response to movement of the actuator along the axis of movement from the ON position toward the OFF position, so that power cannot be supplied from the DC power source to the DC motor via the pair of electrical switch contacts; a power module including at least one solid-state power switching element for controllably supplying power from the DC power source to the DC motor; and a control module including a control circuit for receiving signaling module signals and outputting control module signals in response to the received signaling module signals to control the at least one solid-state power switching element of the power module, the at least one solid-state power switching element controllably supplying power from the DC power source to the DC motor to allow the DC motor to operate at a speed corresponding to the sensed movement or position of the actuator. [Brief explanation of the drawings]

[0024] The present invention can be more fully understood in the following detailed description of the preferred, non-limiting embodiments illustrated in the drawings.

[0025] [Figure 1A]1 shows a perspective view of a signal switch in which a user's finger presses the trigger, causing the actuator to move inward relative to the opening in the case along a movement axis (X-X') from an OFF position to an ON position. When the user's finger releases the trigger, a reset spring causes the actuator to move outward relative to the opening in the case along the movement axis (X-X') from the ON position to the OFF position. [Figure 1B] 1 shows an exploded view of a signal switch in which a user's finger presses the trigger, causing the actuator to move inward relative to the opening in the case along a movement axis (X-X') from an OFF position to an ON position. When the user's finger releases the trigger, a reset spring causes the actuator to move outward relative to the opening in the case along the movement axis (X-X') from an ON position to an OFF position. [Figure 2A] 1 shows a perspective view of an integrated switch in which a user's finger presses the trigger, causing the actuator to move inward relative to the opening in the case along a movement axis (X-X') from an OFF position to an ON position. When the user's finger releases the trigger, a reset spring causes the actuator to move outward relative to the opening in the case along the movement axis (X-X') from the ON position to the OFF position. [Figure 2B] 1 shows an exploded view of an integrated switch in which a user's finger presses the trigger, causing the actuator to move from an OFF position to an ON position along a movement axis (X-X') toward the interior of the opening in the case. When the user's finger releases the trigger, a reset spring causes the actuator to move from the ON position to the OFF position along the movement axis (X-X') toward the exterior of the opening in the case. [Figure 2C]1 shows a cross-sectional view of an integrated switch in which a user's finger presses the trigger, causing the actuator to move inward relative to the opening in the case along a movement axis (X-X') from an OFF position to an ON position. When the user's finger releases the trigger, a reset spring causes the actuator to move outward relative to the opening in the case along the movement axis (X-X') from the ON position to the OFF position. [Figure 3A] 1 shows a perspective view of the first embodiment of the signaling module and actuator attached. When a user's finger presses the trigger, the actuator moves from the OFF position to the ON position along the axis of movement (X-X'). When the user's finger releases the trigger, the reset spring moves the actuator from the ON position to the OFF position along the axis of movement (X-X'). [Figure 3B] 1 shows an exploded view of the first embodiment of the signaling module and actuator attached. When a user's finger presses the trigger, the actuator moves from the OFF position to the ON position along the axis of movement (X-X'). When the user's finger releases the trigger, the reset spring moves the actuator from the ON position to the OFF position along the axis of movement (X-X'). [Figure 4A-4B] 4A and 4B are perspective views of the operation sequence of the signaling module of the first embodiment, in which the rolling material is rotatably bonded to the second film contact surface, thereby causing the rolling material to contact the first conductive layer and the second conductive layer on the first film contact surface with the contact surface of the variable resistor element and the contact surface of the signal control element, respectively; in FIG. 4A, the rolling material is in the ON position, and in FIG. 4B, the rolling material is in the OFF position. [Figure 4C-4D] 4A and 4B show exploded and mounted views of the signaling module of the first embodiment in the on and off positions, respectively, where the signaling module includes a rolling element, a membrane, a spacing element, a contact surface of a variable resistor element, and a contact surface of a signal control element, where the rolling element in FIG. 4C is in the on position, and the rolling element in FIG. 4D is in the off position. [Figures 4E-4F] 4A and 4B show exploded and mounted views of the signaling module of the first embodiment in the on and off positions, respectively, where the signaling module includes a rolling element, a membrane, a spacing element, a contact surface of a variable resistor element, and a contact surface of a signal control element, where the rolling element in FIG. 4E is in the on position and the rolling element in FIG. 4F is in the off position. [Figure 5A] FIG. 5A shows a side view of a signaling module of a first embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element, and the second rolling portion of the rolling element brings the second conductive layer into contact with the contact surface of the signal control element. FIG. 5A shows a case in which one end of the first conductive layer or the second conductive layer is pressed against the circuit board by a contact spring, and the variable resistor element or signal control element in FIG. 5A employs multiple constant resistors connected in series. [Figure 5B] FIG. 5B shows a side view of a signaling module according to a first embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element, and the second rolling portion of the rolling element brings the second conductive layer into contact with the contact surface of the signal control element. FIG. 5B shows a case in which one end of the first conductive layer or the second conductive layer is attached to the circuit board by a conductive adhesive layer, and the variable resistor element or signal control element in FIG. 5B employs multiple constant resistors connected in series. [Figure 5C] FIG. 5B shows a side view of the signaling module of the first embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element, and the second rolling portion of the rolling element brings the second conductive layer into contact with the contact surface of the signal control element. FIG. 5C shows a case in which one end of the first conductive layer or the second conductive layer is pressed against the circuit board by a contact spring, and the variable resistor element or signal control element in FIG. 5C uses a continuous variable resistor. [Figure 5D]FIG. 5D shows a side view of a signaling module according to a first embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element, and the second rolling portion of the rolling element brings the second conductive layer into contact with the contact surface of the signal control element. FIG. 5D shows a case in which one end of the first conductive layer or the second conductive layer is attached to the circuit board by a conductive adhesive layer, and the variable resistor element or signal control element in FIG. 5D uses a continuous variable resistor. [Figure 6A] FIG. 6A shows a control circuit diagram of the electric switch unit of the first embodiment, in which the variable resistor element adopts a continuous variable resistor and the signal control element adopts an NC / NO switching circuit. [Figure 6B] FIG. 6B shows a control circuit diagram of the electric switch unit of the first embodiment, in which the variable resistor element and the signal control element both adopt continuous variable resistors. [Figure 6C] FIG. 6C shows a control circuit diagram of the electric switch unit of the first embodiment, in which the variable resistor element adopts a method in which a plurality of constant resistors are connected in series, and the signal control element adopts an NC / NO switching circuit. [Figure 6D] FIG. 6D shows a control circuit diagram of the electric switch unit of the first embodiment, in which both the variable resistor element and the signal control element adopt a method in which a plurality of constant resistors are connected in series. [Figure 7A] FIG. 7A shows a voltage change diagram of the control circuit shown in FIG. 6A, and FIG. 7A shows a case where the first region changes continuously from low level to high level, and the second region switches from low level to high level. [Figure 7B] FIG. 7B shows the voltage change diagram of the control circuit shown in FIG. 6A, and FIG. 7B shows the case where the first region changes continuously from high level to low level, and the second region switches from low level to high level. [Figure 7C] FIG. 7C shows the voltage change diagram of the control circuit shown in FIG. 6A, and FIG. 7C shows the case where the first region changes continuously from low level to high level, and the second region switches from high level to low level. [Figure 7D]FIG. 7D shows the voltage change diagram of the control circuit shown in FIG. 6A, and FIG. 7D shows the case where the first region changes continuously from high level to low level, and the second region switches from high level to low level. [Figure 7E] FIG. 7E shows a voltage change diagram of the control circuit shown in FIG. 6A, and FIG. 7E shows a case where the first region changes continuously from low level to high level, and the second region switches from low level to high level and from high level to low level. [Figure 7F] FIG. 7F shows a voltage change diagram of the control circuit shown in FIG. 6A, and FIG. 7F shows a case where the first region changes continuously from high level to low level, and the second region switches from low level to high level and from high level to low level. [Figure 8A] FIG. 8A shows a voltage change diagram of the control circuit shown in FIG. 6B, and FIG. 8A shows a case where the first region changes continuously from low level to high level, and the second region changes continuously from high level to low level. [Figure 8B] FIG. 8B shows a voltage change diagram of the control circuit shown in FIG. 6B, and FIG. 8B shows a case where the first region changes continuously from high level to low level, and the second region changes continuously from low level to high level. [Figure 9A] FIG. 9A shows a voltage change diagram of the control circuit shown in FIG. 6C, and FIG. 9A shows a case where the first region changes stepwise from low level to high level, and the second region is switched from low level to high level. [Figure 9B] FIG. 9B shows the voltage change diagram of the control circuit shown in FIG. 6C, and FIG. 9B shows the case where the first region changes stepwise from high level to low level, and the second region switches from low level to high level. [Figure 9C] FIG. 9C shows the voltage change diagram of the control circuit shown in FIG. 6C, and FIG. 9C shows the case where the first region changes stepwise from low level to high level, and the second region is switched from high level to low level. [Figure 9D]FIG. 9D shows the voltage change diagram of the control circuit shown in FIG. 6C, and FIG. 9D shows the case where the first region changes stepwise from high level to low level, and the second region is switched from high level to low level. [Figure 9E] FIG. 6C shows a voltage change diagram of the control circuit, and FIG. 9E shows a case where the first region changes stepwise from low level to high level, and the second region is switched from low level to high level and from high level to low level. [Figure 9F] FIG. 9F shows a voltage change diagram of the control circuit shown in FIG. 6C, and FIG. 9F shows a case where the first region changes stepwise from high level to low level, and the second region is switched from low level to high level and from high level to low level. [Figure 10A] FIG. 10A shows a voltage change diagram of the control circuit shown in FIG. 6D, and FIG. 10A shows a case where the first region changes stepwise from low level to high level, and the second region changes stepwise from high level to low level. [Figure 10B] FIG. 10B shows a voltage change diagram of the control circuit shown in FIG. 6D, and FIG. 10B shows a case where the first region changes stepwise from high level to low level, and the second region changes stepwise from low level to high level. [Figures 11A-11B] 11A and 11B show perspective views of the operation sequence of the signaling module of the second embodiment, in which the rolling material and the second membrane contact surface are rollably joined, whereby the rolling material contacts the first conductive layer on the first membrane contact surface with the contact surface of the variable resistor element, with the rolling material in the on position in FIG. 11A and the rolling material in the off position in FIG. 11B. [Figures 11C-11D] 11A and 11B show exploded and mounted views, respectively, of the signaling module of the second embodiment in the on and off positions, the signaling module including a rolling element, a membrane, a spacing element, and a contact surface of a variable resistor element, in which FIG. 11C shows the rolling element in the on position, and in FIG. 11D the rolling element in the off position. [Figures 11E-11F]11A and 11B show exploded and mounted views, respectively, of the signaling module of the second embodiment in the on and off positions, the signaling module including a rolling element, a membrane, a spacing element, and a contact surface of a variable resistor element, in which FIG. 11E shows the rolling element in the on position, and in FIG. 11F the rolling element in the off position. [Figure 12A] FIG. 12A shows a side view of a signaling module according to a second embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element. FIG. 12A shows a case in which one end of the first conductive layer is pressed against the circuit board by a contact spring, and the variable resistor element in FIG. 12A employs multiple constant resistors connected in series. [Figure 12B] FIG. 12B shows a side view of a signaling module according to a second embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element. FIG. 12B shows a case in which one end of the first conductive layer is bonded to the circuit board by a conductive adhesive layer. The variable resistor element in FIG. 12B employs multiple constant resistors connected in series. [Figure 12C] FIG. 12C shows a side view of a signaling module according to a second embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element. FIG. 12C shows a case in which one end of the first conductive layer and the circuit board are pressed together by a contact spring, and the variable resistor element in FIG. 12C uses a continuous variable resistor. [Figure 12D] FIG. 12D shows a side view of a signaling module according to a second embodiment, in which when the rolling element rolls on the second thin-film contact surface, the first rolling portion of the rolling element brings the first conductive layer into contact with the contact surface of the variable resistor element. FIG. 12D shows a case in which one end of the first conductive layer is adhered to the circuit board by a conductive adhesive layer, and the variable resistor element in FIG. 12D uses a continuous variable resistor. [Figure 13A] FIG. 13A shows a control circuit diagram of the electric switch unit of the second embodiment, in which the variable resistor element adopts a continuous variable resistor. [Figure 13B]FIG. 13B shows a control circuit diagram of the electric switch unit of the second embodiment, in which the variable resistor element adopts a system in which a plurality of constant resistors are connected in series. [Figure 14A] FIG. 14A shows a voltage change diagram of the control circuit shown in FIG. 13A, and FIG. 14A shows a case where the first region changes continuously from a low level to a high level. [Figure 14B] FIG. 14B shows a voltage change diagram of the control circuit shown in FIG. 13A, and FIG. 14B shows a case where the first region changes continuously from a high level to a low level. [Figure 15A] FIG. 15A shows a voltage change diagram of the control circuit shown in FIG. 13B, and FIG. 15A shows a case where the first region changes stepwise from a low level to a high level. [Figure 15B] FIG. 15B shows a voltage change diagram of the control circuit shown in FIG. 13B, and FIG. 15B shows a case where the first region changes stepwise from a high level to a low level. DETAILED DESCRIPTION OF THE INVENTION

[0026] Preferred embodiments of the present invention will now be described with reference to Figures 1A-15B. The present invention will be described herein for use in conjunction with power tools, which may include, for example, hand-operated power drills, power grinders, power sanders, power saws, power rotary drive tools, and the like. While the present invention will be described herein for use in conjunction with power tools, it should be clearly understood that this is merely for ease of illustrating functionality, and that alternative embodiments of the present invention may, of course, be used in conjunction with any other type of electrical equipment, such as power gardening tools. While the power tool embodiments described herein relate to variable speed power tools for purposes of illustration, it should be apparent that alternative embodiments of the present invention may be adapted for use in conjunction with non-variable speed power tools.

[0027] Power tools include brushed or brushless DC motors, which include a rotor and a stator, with the stator providing a magnetic field to drive the rotor. The rotor of a brushless DC motor includes an output shaft supported on a number of bearings to provide output torque and is surrounded by a stationary magnet that generates a magnetic field. The stator is mounted around the rotor, with an air gap between them. Stator windings are located in the air gap and are arranged relatively parallel to the rotor output shaft, and may be connected in a typical delta or three-phase star configuration. When current flows through the stator windings, the current generated in the stator windings generates a magnetic field that magnetically couples to the rotor, causing it to "drag" around the rotor. The rotor moves in rotation by aligning the magnetic field generated by the stationary magnets in the rotor assembly with the magnetic field generated by the stator. Therefore, by sequentially energizing the stator windings in a timed manner, the rotational movement of the rotor shaft can be controlled to achieve any desired operating speed and direction, as described in more detail below.

[0028] 1A-10B and 11A-15B show first and second embodiments of an electrical switch unit of the present invention. Each embodiment includes an electrical switch unit, the electrical switch unit including a case 300, the case 300 including a bottom case 300A and a cover 300B, which may be connected by a snap fit or screws to essentially enclose at least some of the components of a signaling module. The case 300 houses a pair of electrical switch contacts 310 and an actuator 320 operably connected to at least one of the pair of electrical switch contacts 310. The molded plastic case 300 is attached to the body of the power tool adjacent to the handle of the power tool, and the electrical switch contacts 310 are arranged in series in a circuit between a brushed or brushless DC motor of the power tool and a DC power source (e.g., a battery pack). 1A, 1B, and 2A-2C, a user's finger presses trigger 330, causing actuator 320 to move inward relative to the opening in case 300 along axis of movement X-X' from an OFF position to an ON position. When the user's finger releases trigger 330, reset spring 340 causes actuator 320 to move outward relative to the opening in case 300 along axis of movement X-X' from the ON position to the OFF position. Actuator 320 is operably connected to electrical switch contacts 310, such that in response to actuator 320 moving to the ON position, electrical switch contacts 310 form a closed circuit, thereby allowing power from a DC power source to be supplied to a brushed or brushless DC motor via the pair of electrical switch contacts 310. Conversely, in response to actuator 320 being in the OFF position, the pair of electrical switch contacts 310 are placed in an open circuit configuration, thereby preventing the DC power source from supplying power to a brushed or brushless DC motor via the pair of electrical switch contacts 310.Specifically, the pair of electrical switch contacts 310 includes a contact terminal and a fixed terminal. When the trigger 330 is not pressed, one end of the contact terminal faces the fixed terminal and the other end of the contact terminal abuts against the side surface of the actuator 320, in which case the contact terminal and the fixed terminal are disconnected. When the trigger 330 is pressed, the other end of the contact terminal separates from the side surface of the actuator 320, and the tension spring 350 pulls the contact terminal toward the fixed terminal, so that the contact terminal and the fixed terminal are connected and electrically connected. After the trigger 330 is released, the other end of the contact terminal abuts against the side surface of the actuator 320 again, in which case the contact terminal and the fixed terminal are disconnected.

[0029] 3A, 3B, and 4A-4F, depending on the amount of force applied to trigger 330 by a user's finger, actuator 320 can move within a certain range of positions along movement axis X-X', and a brushed or brushless DC motor is configured to be operated at a variable operating speed by linear movement of actuator 320 along movement axis X-X'. Specifically, actuator 320 is connected to a signaling module disposed in case 300, and the signaling module includes a signaling circuit that senses the linear movement of actuator 320 relative to a reference position and outputs a signaling module signal that indicates the sensed movement or position of actuator 320, thereby indicating the motor operating speed desired by the user.

[0030] 2A-2C, a power module 360 ​​is provided, which includes at least one solid-state power switching device, which in this example is a MOSFET, each connected in series with a corresponding stator winding of a brushed or brushless DC motor via a motor cable. The MOSFETs are arranged so that current can be selectively and controllably applied to the input of the corresponding stator winding of the brushed or brushless DC motor. By sequentially activating each stator winding according to a timing and sequence controlled with reference to a control module, the rotor's permanent magnets sequentially follow the propulsion magnetic field generated by the stator windings.

[0031] 2A-2C, a control module 370 including motor control circuitry receives signaling module signals from the signaling module and, in response to the received signaling module signals, outputs control module 370 electrical signals to operate a power module 360, which includes a plurality of MOSFETs connected to corresponding input terminals of the stator windings of a brushless DC motor. The control module 370 includes a microcontroller programmed to output control module 370 signals that drive the plurality of MOSFETs of the power module 360 ​​to energize corresponding stator windings according to a predetermined timing and sequence, so that the brushless DC motor operates in a predetermined manner (i.e., speed, direction, torque) corresponding to the movement of the actuator 320 dictated by the signaling module signals. The speed and torque of a brushed or brushless DC motor depend on the amount of power available to the stator windings via the corresponding input MOSFETs of the stator windings. In these embodiments, the amount of power delivered to the stator windings can be controllably varied using pulse-width modulation techniques, such that the output of a timing generator (e.g., a 555 circuit) is used as an input to the gates of the MOSFETs to suitably achieve high-speed switching of the MOSFETs, such that the power obtained by switching the MOSFETs into the stator windings provides the desired speed and torque generated by a brushed or brushless DC motor. The timing generator signal may then be used as a signal to control module 370 to control the operation of the MOSFETs. In some embodiments, control module 370 may include voltage regulation and protection circuitry to regulate the input voltage from the DC power source to each MOSFET.

[0032] In an embodiment of the present invention, the control module 370 is electrically integrated with the electrical switch contacts 310 and / or the signaling module, thereby allowing a relative direct electrical communication between the electrical switch contacts 310 and / or the signaling module and the control module 370. In this regard, the control module 370 and the signaling module can generally be formed on a single circuit board 120 and can be integrally formed on the circuit board itself, thereby providing a direct electrical connection. Specifically, the electrical connection between the electrical switch contacts 310, the signaling module, and the control module 370 is provided by conductive pins, conductive paths, conductive buses, etc., which can be integrally inserted into the circuit board 120 itself. The electrical switch unit shown in FIGS. 2A-2C is an integrated switch with a switch module (integrated switch), in which the control module 370 and the power module 360 ​​are further integrated on the circuit board 120 in addition to the signaling module. The integrated switch integrates the previously separate signal switch and control module 370, thereby simplifying installation and reducing installation time. In some embodiments, the signaling module and the control module 370 may be formed on physically separate circuit boards, and the physically separate circuit boards may be appropriately positioned relative to each other to allow a relatively direct and integrated electrical connection between the control module 370 and the electrical switch contacts 310 and / or the signaling module, and the electrical switch unit shown in Figures 1A and 1B is a separate switch (signal switch) without a switch module, has a signaling module, does not have the control module 370 and the power module 360, and may be connected to the circuit board on which the control module 370 and the power module 360 ​​are integrated by a bent wire 400 and a cable 410.

[0033] In an embodiment of the present invention, power module 360, along with control module 370 and signaling module of the electrical switch unit, are integrally formed on a single circuit board 120. As shown in FIGS. 2A-2C , because the MOSFETs disposed in power module 360 ​​tend to generate a relatively large amount of thermal energy, one or more heat dissipation and / or diffusion elements, such as heat dissipation fins 380, are attached to the surface of power module 360 ​​to dissipate and / or diffuse the thermal energy from the MOSFETs to the air in the surrounding environment. Due to the irregular surfaces of the typical topology of the MOSFETs and other components in power module 360, thermally conductive pads, thermally conductive paste, or thermally conductive compound can be used as intermediate heat transfer layers between the surfaces of the MOSFETs and elements such as heat dissipation fins 380 to achieve more efficient thermal communication with the MOSFETs. In some embodiments, signaling module and control module 370 may be integrally formed on a single circuit board, while power module 360 ​​is formed on a separate, physically separate circuit board. The two circuit boards can be mounted to each other in a parallel spaced apart configuration or in a relatively perpendicular configuration such that thermal energy from the MOSFETs mounted on the power module 360 ​​is isolated from the control module 370 and signaling module circuit boards, thereby reducing the possibility of thermal damage to these modules.

[0034] In an embodiment of the present invention, a direction control assembly is further provided, which includes, as shown in FIGS. 1A, 1B and 2A-2C, a turn bar 390 rotatably connected to the case 300, a slider member 420 operably connected to the other end of the turn bar 390, and a direction switching structure for controlling the steering of a brushed or brushless DC motor, which is provided between the slider member 420 and the circuit board 120, and the slider member 420 is provided on one side of the rotation plane of the turn bar 390, and the slider member 420 is driven by the turn bar 390 and is connected to the direction switching structure so as to be reciprocable, and the direction switching structure is provided on the slider member 420 facing the circuit board 120. The direction control assembly includes a direction-switching brush piece 430 mounted on the slider member 420, and first, second, and third conductive pieces mounted at intervals on the circuit board along the movement path of the slider member 420. One end of the direction-switching brush piece 430 is always slidably connected to the first conductive piece, and the other end alternately slides between the second and third conductive pieces. As can be seen from the above structure, when the turn bar 390 rotates, the direction-switching brush piece 430 on the slider member 420 drives the direction-switching structure of the circuit board 120 to slip, and generates a signal to control the direction switching of the brushed or brushless DC motor, and the control module 370 receives and processes the control signal. The specific operation process of the direction control assembly is as follows: When the turn bar 390 is in the center position, one end of the direction-switching brush 430 is always connected to the first conductive piece, and the other end is located between the second and third conductive pieces. At this time, the switch is not energized and no brushed or brushless DC motor signal is generated. When the turn bar 390 rotates clockwise, the direction-switching brush 430 is connected to the first and third conductive pieces, respectively. At this time, when the switch is energized, a forward signal for the brushed or brushless DC motor is generated. When the turn bar 390 rotates counterclockwise, the direction-switching brush 430 is connected to the first and second conductive pieces, respectively. At this time, when the switch is energized, a reverse signal for the brushed or brushless DC motor is generated, thereby realizing direction switching control of the brushed or brushless DC motor. In this embodiment, at least a portion of the signaling circuit is formed on the circuit board 120. Specifically, as shown in Figures 4A-4B-4E-4F and 5A-5D, the circuit board 120 includes a first region having a variable resistor element and a second region having a signal control element, where the variable resistor element has a variable resistor element contact surface 110A and the signal control element has a signal control element contact surface 110B. In this embodiment, the variable resistor element located in the first region can be accessed using a continuous variable resistor or a plurality of constant resistors connected in series, and the signal control element located in the second region can be accessed using a continuous variable resistor or a plurality of constant resistors connected in series, or an NC / NO switching circuit. Optionally, when the variable resistor element employs a continuous variable resistor and the signal control element employs an NC / NO switching circuit, its control circuit diagram is shown in Figure 6A and its voltage change diagram is shown in Figures 7A-7F; when both the variable resistor element and the signal control element employ a continuous variable resistor, its control circuit diagram is shown in Figure 6B and its voltage change diagram is shown in Figures 8A and 8B; when the variable resistor element employs a series-connected constant resistor and the signal control element employs an NC / NO switching circuit, its control circuit diagram is shown in Figure 6C and its voltage change diagram is shown in Figures 9A-9F; when both the variable resistor element and the signal control element employ a series-connected constant resistor, its control circuit diagram is shown in Figure 6D and its voltage change diagram is shown in Figures 10A and 10B. The control circuit is used to receive signals from the variable resistor element and the signal control element, and output signals to the control module 370 in response to the received signaling module signals. Specifically, as shown in Figures 6A to 6D, the variable resistor element in the first region has one end connected to the positive pole of the constant voltage power supply and the other end connected to the negative pole of the constant voltage power supply, the signal control element in the second region has one end connected to the normally closed terminal and the other end connected to the normally open terminal, and the connection end between the variable resistor element and the negative pole of the power supply is further electrically connected to a direction switching structure of a direction control assembly, thereby realizing direction switching control of a brushed or brushless DC motor.The bottom surface of the first conductive layer 130A faces and is connected to the contact surface 110A of the variable resistor element, one end of the first conductive layer 130A is connected to the output terminal, the bottom surface of the second conductive layer 130B faces and is connected to the contact surface 110B of the signal control element, and one end of the second conductive layer 130B is connected to the common terminal.

[0035] As an example, if the variable resistor element or signal control element employs a system in which multiple constant resistors are connected in series, the variable resistor element or signal control element may include, for example, nine resistors (one set) and may be configured to be connected in series between the power supply of the electrical device and the input pin of the control module 370. Eight conductive wires extend from eight intermediate nodes between the nine series-connected resistors, and these eight conductive wires are printed on the surface of the circuit board 120 to form an array of single discrete wires on the contact surface 110A of the variable resistor element or the contact surface 110B of the signal control element. As can be seen, by selectively electrically bridging different wires on the contact surface 110A of the variable resistor element or the contact surface 110B of the signal control element to the first conductive layer 130A or the second conductive layer 130B, respectively, a selectable variable voltage can be applied to the input pin of the control module 370. In a specific embodiment of the present invention, the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element are arranged in parallel on the same plane, and the first region and the second region are arranged to be physically separated and partitioned, for example, two independent elongated strips may be printed on the surface of the circuit board 120, as shown in Figures 4A-4B-4E-4F.

[0036] 5A-5D, the signaling module further includes a relatively thin and flexible membrane 130, which may be formed, for example, from a polymer, copolymer, or polymer composite material. The membrane 130 includes a first membrane contact surface 130C on the lower surface of the membrane 130 and a second membrane contact surface 130D on the upper surface of the membrane 130, and the first membrane contact surface 130C on the lower surface of the membrane 130 has a first conductive layer 130A and a second conductive layer 130B. The first conductive layer 130A and the second conductive layer 130B are formed by a conductive material printed on the first membrane contact surface 130C of the membrane 130. The film 130 is adhesively attached to the circuit board 120, so that the first film contact surface 130C of the film 130 faces the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element, and is separated from the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element by a spacing element 140, thereby forming a space 150 between them. The spacing element 140 surrounds the periphery of the film 130 and is located between the first conductive layer 130A, the second conductive layer 130B and the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element. The spacing element 140 may comprise a polymer, copolymer, or polymer composite material, and has one end adhesively bonded to the first conductive layer 130A and the second conductive layer 130B of the first membrane contact surface 130C, and the other end adhesively bonded to the variable resistor element contact surface 110A and the signal control element contact surface 110B. By default, the first conductive layer 130A and the second conductive layer 130B are biased to a position that is partitioned relative to the variable resistor element contact surface 110A and the signal control element contact surface 110B. This bias can be achieved by configuring the structure of the membrane 130 itself and / or by using an external biasing element such as the spacing element 140, so that the first conductive layer 130A and the second conductive layer 130B are electrically connected to the variable resistor element contact surface 110A and the signal control element contact surface 110B, respectively, at a certain contact point, regardless of whether the user presses the trigger 330.

[0037] In this embodiment, one end of the first conductive layer 130A and one end of the second conductive layer 130B of the first membrane contact surface 130C are electrically connected to the circuit board 120, for example, by a lead wire. In this embodiment, one end of the first conductive layer 130A and one end of the second conductive layer 130B of the first membrane contact surface 130C of the membrane 130 are respectively in contact with and connected to the circuit board 120. Optionally, two contact springs 170 can be used to press one end of the first conductive layer 130A and one end of the second conductive layer 130B of the first membrane contact surface 130C against the circuit board 120, respectively, to achieve electrical connection. The pressure of the contact springs 170 can cause one end of the first conductive layer 130A and one end of the second conductive layer 130B of the first membrane contact surface 130C to contact the circuit board 120 (contact position 190), as shown in FIGS. 5A and 5C . An electrical connection (contact position 190) may be achieved by adhering one end of the first conductive layer 130A and one end of the second conductive layer 130B of the first membrane contact surface 130C of the membrane 130 to the circuit board 120 using a conductive adhesive layer 180 (e.g., conductive paste, conductive tape, or glue such as epoxy gel, polyurethane gel, and acrylic gel), as shown in Figures 5B and 5D. In some embodiments, the electrical connection may be achieved by welding one end of the first conductive layer 130A and one end of the second conductive layer 130B of the first membrane contact surface 130C of the membrane 130 to the circuit board 120 using a silver welding rod or the like.

[0038] In this embodiment, the moving means is operably connected to the actuator 320 and is configured to be used to move along the second membrane contact surface 130D of the membrane 130 in response to movement of the actuator 320. The moving means may employ a sliding member such as a slider or a slide piece, and in this embodiment of the present invention, the moving means is a rolling member 100, for example, a roller, and is used to rollably move on the second membrane contact surface 130D of the membrane 130, thereby reducing friction and wear between the rolling member 100, the membrane 130, and the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element, and the reliability and stability of the operation of the electrical switch unit can be maintained for a longer duration of use. As shown in Figures 4A-4F, the rolling material 100 includes a first rolling portion 100A and a second rolling portion 100B, and as the rolling material 100 moves along the second film contact surface 130D of the film 130, the rolling material 100 applies an up and down force to the second film contact surface 130D of the film 130, causing the first conductive layer 130A and the second conductive layer 130B of the first film contact surface 130C to contact the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element, respectively, via multiple contact structures. In each of the plurality of contact point structures, the contact point is formed such that the first rolling portion 100A of the rolling element 100 contacts a portion of the first conductive layer 130A with the contact surface 110A of the variable resistor element, and the second rolling portion 100B contacts a portion of the second conductive layer 130B with the contact surface 110B of the signal control element. Thus, by the rolling element 100 rolling along the second film contact surface 130D of the film 130, the first conductive layer 130A and the second conductive layer 130B can be selectively electrically bridged to the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element, and the effective resistances of the variable resistor element and the signal control element can be controllably changed correspondingly, thereby applying a changing voltage signal to the input end of the control module 370. The variable voltage input directs movement of the actuator 320, and the control module 370 is programmed to control the operation of a brushed or brushless DC motor with reference to the variable voltage signal.It should be noted that the signal control element may employ an NC / NO switching circuit to perform signal control, and the circuit of the signal control element is configured to switch signals in response to contacting the second conductive layer with the contact surface of the signal control element at one of the plurality of contact point structures, and the selectable signals include, but are not limited to, on / off, selection of different signals, etc.

[0039] In this embodiment, as shown in FIGS. 3A and 3B , the rolling element 100 may be biased by a compression spring 100C in a direction substantially perpendicular to the direction of movement of the rolling element 100. The rolling element 100 may be attached to a bracket 100E by a pin shaft 100D, and the bracket 100E is mounted in a groove on one side of the actuator 320 near the circuit board 120. The rolling element 100 may be a sphere, an ellipsoid, a cylinder, or any other shape suitable for rolling. The structures of the first rolling portion 100A and the second rolling portion 100B of the rolling element 100 may be selected to match the structures of the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element. In this embodiment, the first rolling portion 100A and the second rolling portion 100B are independently separated and partitioned.

[0040] In this embodiment, exhaust holes 160 are formed through the upper and lower surfaces of the circuit board 120 at positions corresponding to the exhaust holes 160 on the circuit board 120. Optionally, circular holes are formed in the spacing element 140 at positions corresponding to the exhaust holes 160 on the circuit board 120, and the circular holes are connected to the spaces 150 corresponding to the contact surfaces 110A of the variable resistor element and the contact surfaces 110B of the signal control element via first and second slit holes, respectively. When the rolling element 100 rolls along the second membrane contact surface 130D of the membrane, the space 150 surrounded by the spacing element 140 is compressed, and the exhaust holes 160 are used to exhaust air when the space 150 is compressed.

[0041] In the signaling module of the electrical switch unit, the first conductive layer 130A and the second conductive layer 130B of the first membrane contact surface 130C are separated from the contact surface 110A of the variable resistor element and the contact surface 110B of the signal control element by the spacing element 140, respectively, so that the dimensions of the membrane 130, the spacing element 140 and the circuit board 120 can be reduced, thereby reducing the space occupied by the actuator 320 and the electrical switch, and also reducing the number of moving means, reducing the number from the conventional two sets of moving means to one set of moving means, which is advantageous in reducing material costs.

[0042] In a second embodiment, the signaling circuit is at least partially formed on a circuit board 220. Specifically, as shown in FIGS. 11A-11B-11E-11F and 12A-12D, the circuit board 220 includes a first region having a variable resistor element, the variable resistor element having a variable resistor element contact surface 210A. In an embodiment of the present invention, the variable resistor element located in the first region can be accessed using a continuous variable resistor or a method in which multiple constant resistors are connected in series. Optionally, if the variable resistor element uses a continuous variable resistor, its control circuit diagram is shown in FIG. 13A and its voltage change diagram is shown in FIGS. 14A and 14B. If the variable resistor element uses a method in which multiple constant resistors are connected in series, its control circuit diagram is shown in FIG. 13B and its voltage change diagram is shown in FIGS. 15A and 15B. 13A and 13B, one end of the variable resistor element in the first region is connected to the positive electrode of the power supply and the other end is connected to the negative electrode of the power supply, and the connection end between the variable resistor element and the negative electrode of the power supply is further electrically connected to the direction switching structure of the direction control assembly to realize the direction switching control of the brushed or brushless DC motor. The bottom surface of the first conductive layer 130A is connected to and faces the contact surface 210A of the variable resistor element, and one end of the first conductive layer 230A is connected to the output terminal.

[0043] As an example, if the variable resistor element employs a configuration in which multiple constant resistors are connected in series, the variable resistor element may include, for example, nine resistors (one set) and may be configured to be connected in series between the power source of the electrical device and the input pin of the control module 370. Eight conductive wires extend from eight intermediate nodes between the nine series-connected resistors, and these eight conductive wires are printed on the surface of the circuit board 220 to form an array of single discrete wires on the contact surface 210A of the variable resistor element. As can be seen, by selectively electrically bridging different wires on the contact surface 210A of the variable resistor element to the first conductive layer 230A, respectively, a selectable variable voltage can be applied to the input pin of the control module 370.

[0044] 12A-12D, the signaling module further includes a relatively thin and flexible membrane 230, which may be formed, for example, of a polymer, copolymer, or polymer composite material. The membrane 230 includes a first membrane contact surface 230C on the lower surface of the membrane 230 and a second membrane contact surface 230D on the upper surface of the membrane 230, with the first membrane contact surface 230C on the lower surface of the membrane 230 having a first conductive layer 230A. The first conductive layer 230A is formed by a conductive material printed on the first membrane contact surface 230C of the membrane 230. The membrane 230 is adhesively attached to the circuit board 220, such that the first membrane contact surface 230C of the membrane 230 faces the contact surface 210A of the variable resistor element and is separated from the contact surface 210A of the variable resistor element by a spacing element 240, thereby forming a space 250 between the two. The spacing element 240 surrounds the periphery of the membrane 230 and is positioned between the first conductive layer 230A and the variable resistor element contact surface 210A. The spacing element 240 may comprise a polymer, copolymer, or polymer composite, and has one end adhesively bonded to the first conductive layer 230A of the first membrane contact surface 230C and the other end adhesively bonded to the variable resistor element contact surface 210A. By default, the first conductive layer 230A is biased to a position that is partitioned relative to the variable resistor element contact surface 210A. This bias can be achieved by configuring the structure of the membrane 230 itself and / or by using an external biasing element such as the spacing element 240, so that the first conductive layer 230A and the variable resistor element contact surface 210A are connected and conductive at a certain contact point, regardless of whether the user presses the trigger 330.

[0045] In this alternative embodiment, one end of the first conductive layer 230A of the first membrane contact surface 230C is electrically connected to the circuit board 220, for example, by a lead wire. In this embodiment, one end of the first conductive layer 230A of the first membrane contact surface 230C of the membrane 230 is in contact with and connected to the circuit board 220. Optionally, one end of the first conductive layer 230A of the first membrane contact surface 230C can be pressed against the circuit board 220 by a contact spring 270 to achieve electrical connection, and the pressure of the contact spring 270 can bring one end of the first conductive layer 230A of the first membrane contact surface 230C into contact with the circuit board 220 (contact position 290), as shown in Figures 12A and 12C. An electrical connection (contact location 290) may be achieved by adhering one end of the first conductive layer 230A of the first membrane contact surface 230C of the membrane 230 to the circuit board 220 with a conductive adhesive layer 280 (e.g., conductive paste, conductive tape, or glue such as epoxy gel, polyurethane gel, and acrylic gel), as shown in Figures 12B and 12D. In some embodiments, the electrical connection may be achieved by welding one end of the first conductive layer 230A of the first membrane contact surface 230C of the membrane 230 to the circuit board 220 with a silver welding rod or the like.

[0046] In this alternative embodiment, the moving means is operably connected to the actuator 320 and is configured to be used in response to the moving means moving along the second membrane contact surface 230D of the membrane 230. The moving means may employ a sliding member such as a slider or a slide piece, and in this embodiment of the present invention, the moving means is a rolling member 200, for example a roller, which is used to rollably move on the second membrane contact surface 230D of the membrane 230, thereby reducing friction and wear between the rolling member 200, the membrane 230 and the contact surface 210A of the variable resistor element, and the reliability and stability of the operation of the electrical switch unit can be maintained for a longer duration of use. 11A-11B to 11E-11F, the rolling element 200 includes a first rolling portion 200A, whereby, as the rolling element 200 moves along the second film contact surface 230D of the film 230, the first conductive layer 230A of the first film contact surface 230C and the contact surface 210A of the variable resistor element come into contact at a plurality of contact point structures due to the vertical force applied from the rolling element 200 to the second film contact surface 230D of the film 230. In each of the plurality of contact point structures, a contact point is formed by the first rolling element 200A of the rolling element 200 to bring a portion of the first conductive layer 230A into contact with the contact surface 210A of the variable resistor element. Thus, as the rolling element 200 rolls along the second membrane contact surface 230D of the membrane 230, the first conductive layer 230A can be selectively electrically bridged to the contact surface 210A of the variable resistor element, and the effective resistance of the variable resistor element can be controllably changed correspondingly, thereby applying a varying voltage signal to the input of the control module 370. The variable voltage input directs movement of the actuator 320, and the control module 370 is programmed to control the operation of a brushed or brushless DC motor with reference to the variable voltage signal.

[0047] In this alternative embodiment, the rolling element 200 may be biased by a compression spring 200C in a direction substantially perpendicular to the direction of movement of the rolling element 200. The rolling element 200 may also be attached to a bracket 200E by a pin shaft 200D, and the bracket 200E is attached in a groove on one side of the actuator 320 near the circuit board 120, and the rolling element 200 may be a sphere, an ellipsoid, a cylinder, or any other shape suitable for rolling.

[0048] In this alternative embodiment, exhaust holes 260 are formed through the upper and lower surfaces of the circuit board 220 at positions corresponding to the space 250 in the circuit board 220. Optionally, circular holes are formed in the spacing element 240 at positions corresponding to the exhaust holes 260 in the circuit board 220, and the circular holes communicate with the corresponding space 250 via slit holes to connect the contact surface 210A of the variable resistor element to the corresponding space 250. When the rolling element 200 rolls along the second membrane contact surface 230D of the membrane, the space 250 surrounded by the spacing element 240 is compressed, and the exhaust holes 260 are used to exhaust air when the space 250 is compressed.

[0049] In the signaling module of the electrical switch unit, the first conductive layer 230A of the first membrane contact surface 230C is separated from the contact surface 210A of the variable resistor element by the spacing element 240, which allows the dimensions of the membrane 230, spacing element 240 and circuit board 220 to be reduced, thereby reducing the space occupied by the actuator 320 and the electrical switch, and also reducing the number of moving means, from the conventional two sets of moving means to one set of moving means, which is advantageous in reducing material costs. In an alternative embodiment of the present invention, the following arrangement may be used, for example, the circuit board may be manufactured from a flexible film material, and the rolling portion of the rolling member may be configured to contact the circuit board and the variable resistor element in a manner opposite to that of the above embodiment.

[0050] As will be appreciated by those skilled in the art, the invention described herein may be varied and modified, apart from as specifically described, without departing from the scope of the invention. It will be apparent to those skilled in the art that all such variations and modifications are within the spirit and scope of the invention as described herein. As will be appreciated, the invention includes all such variations and modifications. The invention further includes all steps or features cited or indicated in the specification, singly or collectively, and any and all combinations of any two or more of the above steps or features.

[0051] The reference herein to any prior art should not be taken as an admission or implied that the prior art forms part of the common general knowledge.

Claims

1. 1. An electric switch unit for an electric device, used to control the operation of a DC motor of the electric device, comprising: a case configured to house an actuator movably mounted to the case, the actuator being responsive to operation of a finger operable trigger to be movable along an axis of movement from an OFF position toward an ON position in a direction toward the interior of an opening in the case, and to be movable along the axis of movement from the ON position toward the exterior of the opening in the case toward the OFF position; a signaling module associated with the electrical switch unit and including a signaling circuit, the signaling circuit adapted to sense movement of the actuator and output a signaling module signal indicative of the sensed movement or position of the actuator; The signaling module includes: a circuit board including a first region having a variable resistor element with a contact surface of the variable resistor element; a membrane including a first membrane contact surface and a second membrane contact surface, the first membrane contact surface of the membrane having a first conductive layer, the first conductive layer of the first membrane contact surface being separated from the contact surface of the variable resistor element by a spacing element, thereby forming a space between them, and one end of the first conductive layer of the first membrane contact surface being electrically connected to the circuit board; a moving means operably connected to the actuator, the moving means configured to move relative to a second membrane contact surface of the membrane in response to movement of the actuator and to bring a first conductive layer of the first membrane contact surface into contact with a contact surface of the variable resistor element at a plurality of contact point structures, whereby an effective resistance of the variable resistor element changes in response to contacting the first conductive layer of the first membrane contact surface with the contact surface of the variable resistor element at each of the plurality of contact point structures.

2. 2. The electrical switch unit according to claim 1, wherein the variable resistor element is accessed by adopting a continuous variable resistor or a method in which a plurality of constant resistors are connected in series.

3. 2. The electrical switch unit according to claim 1, wherein exhaust holes are formed through the upper and lower surfaces of the circuit board at positions corresponding to the spaces in the circuit board.

4. The electrical switch unit according to claim 1 , wherein one end of the first conductive layer of the first membrane contact surface is connected in contact with the circuit board.

5. 5. The electrical switch unit of claim 4, wherein a contact spring is disposed at one end of the second membrane contact surface corresponding to the first conductive layer of the first membrane contact surface, and the pressure of the contact spring can cause the one end of the first conductive layer of the first membrane contact surface to contact and connect with the circuit board.

6. The electrical switch unit according to claim 4 , wherein one end of the first conductive layer of the first membrane contact surface is adhered to the circuit board by a conductive adhesive layer.

7. The electrical switch unit a pair of electrical switch contacts, at least one of which is operably connected to the actuator, the pair of electrical switch contacts being arranged in a structure to close in response to movement of the actuator along the axis of movement from the OFF position toward the ON position, so that power can be supplied from a DC power source to the DC motor via the pair of electrical switch contacts, and the pair of electrical switch contacts being arranged in a structure to open in response to movement of the actuator along the axis of movement from the ON position toward the OFF position, so that power cannot be supplied from the DC power source to the DC motor via the pair of electrical switch contacts; a power module including at least one solid state power switching device for controlling the supply of power from the DC power source to the DC motor; 2. The electrical switch unit of claim 1, further comprising: a control module including control circuitry for receiving the signaling module signal and outputting a control module signal in response to the received signaling module signal to control the at least one solid state power switching element of the power module, the at least one solid state power switching element controlling the supply of power from the DC power source to the DC motor to allow the DC motor to operate at a speed corresponding to the sensed actuator movement or position.

8. 1. An electric switch unit for an electric device, used to control the operation of a DC motor of the electric device, comprising: a case configured to accommodate an actuator movably attached to the case, the actuator being responsive to operation of a finger-operable trigger, the actuator being movable along a movement axis from an OFF position toward an ON position in a direction toward the interior of an opening in the case, and being movable along the movement axis from the ON position toward the exterior of the opening in the case; a signaling module associated with the electrical switch unit and including a signaling circuit, the signaling circuit adapted to sense movement of the actuator and output a signaling module signal indicative of the sensed movement or position of the actuator; The signaling module includes: a circuit board including a first region having a variable resistor element and a second region having a signal control element, the first region and the second region being arranged so as to be physically separated and partitioned, the variable resistor element having a variable resistor element contact surface, and the signal control element having a signal control element contact surface; a membrane including a first membrane contact surface and a second membrane contact surface, the first membrane contact surface of the membrane having a first conductive layer and a second conductive layer, the first conductive layer and the second conductive layer of the first membrane contact surface being separated from the contact surface of the variable resistor element and the contact surface of the signal control element by spacing elements, respectively, thereby forming spaces between them, and one end of the first conductive layer and the second conductive layer of the first membrane contact surface being electrically connected to the circuit board, respectively; a moving means operably connected to the actuator, the moving means configured to move relative to a second membrane contact surface of the membrane in response to movement of the actuator and to bring a first conductive layer of the first membrane contact surface into contact with a contact surface of the variable resistor element at a plurality of contact point structures, whereby an effective resistance of the variable resistor element is changed in response to contacting the first conductive layer of the first membrane contact surface with the contact surface of the variable resistor element at each of the plurality of contact point structures; the moving means is responsive to moving along the second membrane contact surface of the membrane to bring the second conductive layer of the first membrane contact surface into contact with the contact surface of the signal control element at a plurality of contact point structures, whereby an effective resistance of the signal control element is configured to change in response to contacting the second conductive layer of the first membrane contact surface with the contact surface of the signal control element at each of the plurality of contact point structures, or a circuit of the signal control element is configured to switch a signal in response to contacting the second conductive layer of the first membrane contact surface with the contact surface of the signal control element at one of the plurality of contact point structures.

9. 9. The electrical switch unit according to claim 8, wherein the variable resistor element is accessed by adopting a continuous variable resistor or a method in which a plurality of constant resistors are connected in series.

10. 9. The electrical switch unit according to claim 8, wherein the signal control element is accessed by using a continuously variable resistor or a plurality of constant resistors connected in series, or by using an NC / NO switching circuit.

11. 9. The electrical switch unit of claim 8, wherein the moving means is a rolling element, the rolling element including a first rolling portion and a second rolling portion, the first rolling portion configured to be used to contact the first conductive layer with a contact surface of the variable resistor element, and the second rolling portion configured to be used to contact the second conductive layer with a contact surface of the signal control element.

12. 9. The electric switch unit according to claim 8, wherein exhaust holes are formed through the upper and lower surfaces of the circuit board at positions on the circuit board corresponding to the spaces.

13. 9. The electrical switch unit according to claim 8, wherein one ends of the first conductive layer and the second conductive layer of the first membrane contact surface are respectively connected to and in contact with the circuit board.

14. 14. The electrical switch unit of claim 13, wherein contact springs are disposed at one end of the second membrane contact surface corresponding to the first conductive layer and the second conductive layer of the first membrane contact surface, and the pressure of the contact springs can bring one end of the first conductive layer and the second conductive layer of the first membrane contact surface into contact with and connect to the circuit board, respectively.

15. 14. The electrical switch unit according to claim 13, wherein one end of the first conductive layer and one end of the second conductive layer of the first membrane contact surface are respectively adhered to the circuit board by a conductive adhesive layer.

16. The electrical switch unit a pair of electrical switch contacts, at least one of which is operably connected to the actuator, the pair of electrical switch contacts being arranged in a structure to close in response to movement of the actuator along the axis of movement from the OFF position toward the ON position, so that power can be supplied from a DC power source to the DC motor via the pair of electrical switch contacts, and the pair of electrical switch contacts being arranged in a structure to open in response to movement of the actuator along the axis of movement from the ON position toward the OFF position, so that power cannot be supplied from the DC power source to the DC motor via the pair of electrical switch contacts; a power module including at least one solid state power switching device for controlling the supply of power from the DC power source to the DC motor; 9. The electrical switch unit of claim 8, further comprising: a control module including control circuitry for receiving the signaling module signal and outputting a control module signal in response to the received signaling module signal to control the at least one solid state power switching element of the power module, the at least one solid state power switching element controllingly supplying power from the DC power source to the DC motor to allow the DC motor to operate at a speed corresponding to the sensed actuator movement or position.

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