Automatic arm raising device

Abstract

An automatic arm lifting device includes a base, a driving mechanism and an arm lifting mechanism. The driving mechanism includes a stepping motor mounted on the base and a rotating shaft set driven by the stepping motor. The rotating shaft set includes a rotating main rod part and an eccentric protruding part. The eccentric protruding part protrudes from an end surface of the rotating main rod part. The arm lifting mechanism includes a fixed sleeve mounted on the base, a lifting shaft rod movably arranged on the eccentric protruding part and a support platform connected to the lifting shaft rod and capable of supporting a tone arm. The eccentric protruding part drives the lifting shaft rod to move between a raised position and a lowered position. The stepping motor and the eccentric protruding part are designed to drive the lifting shaft rod to move. In addition, the stepping motor directly drives the eccentric protruding part to rotate, which can improve the problem of motor idling.

Description

Technical Field

[0001] This utility model relates to a lifting arm device, and more particularly to an automatic lifting arm device suitable for turntables. Background Technology

[0002] The main function of a turntable is to place a tonearm with a stylus on a record. As the record rotates, the stylus reads grooves of different depths on the record. The resulting electrical signal is converted from the vibration intensity and then played back using the turntable or an external speaker.

[0003] When a track finishes playing, or when it's time to stop playing, the tonearm usually needs to be lifted. Because the stylus needs to lightly touch the grooved surface to read the analog electrical signals formed by the fine grooves of varying depths, it is extremely sensitive and fragile. Therefore, one of the research goals in this field is to find a way to stably lift or lower the tonearm without causing mechanical idling and shortening its lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic arm-raising device that can overcome at least one of the shortcomings of the prior art.

[0005] The automatic arm lifting device of this utility model is applicable to a tonearm of a turntable and includes a base, a drive mechanism, and an arm lifting mechanism.

[0006] This base is suitable for installation on this turntable.

[0007] The drive mechanism includes a stepper motor mounted on the base and a rotating shaft assembly mounted on the stepper motor. The rotating shaft assembly includes a rotating main rod connected to the stepper motor and an eccentric protrusion. The rotating main rod includes an end face opposite to the stepper motor, from which the eccentric protrusion extends. The rotating shaft assembly is driven to rotate by the stepper motor, allowing the eccentric protrusion to rotate about its axis within a predetermined angle range.

[0008] The lifting mechanism includes a fixed sleeve mounted on the base, a lifting shaft that is movable up and down through the fixed sleeve, and a support platform connected to a top end of the lifting shaft. The lifting shaft rests against the eccentric protrusion.

[0009] When the rotating shaft assembly rotates, the eccentric protrusion drives the lifting shaft to move up and down relative to the fixed sleeve between a raised position and a lower position. The height of the support platform in the raised position is higher than the height of the support platform in the lower position, so that the tonearm can be placed on it.

[0010] The automatic arm raising device of this utility model further includes a sensing module and a control module. The sensing module is adapted to be connected to the control module and installed on the base. The sensing module senses the rotation state of the rotating shaft assembly of the drive mechanism and changes between a first state and a second state. In the first state, the sensing module generates a first sensing signal that is transmitted to the control module. In the second state, the sensing module generates a second sensing signal that is transmitted to the control module.

[0011] The automatic lifting arm device of this utility model, when the rotating shaft assembly rotates, the eccentric protrusion relative to the base switches between a raised state at a first height and a lowered state at a second height, so that the lifting shaft moves up and down relative to the fixed sleeve between the raised position and the lowered position. The first height is greater than the second height, and the predetermined angle range of the eccentric protrusion rotating around the axis is greater than 0 degrees and less than 180 degrees.

[0012] The automatic lifting arm device of this utility model includes a lifting main rod connected to the support platform and a swing rest part extending downward from the bottom end of the support platform in the opposite direction of the lifting main rod part. The swing rest part includes a swing rest surface that swings against the eccentric protrusion part.

[0013] The automatic lifting arm device of this utility model includes an eccentric protrusion of the rotating shaft assembly, which includes a support surface on which the lifting shaft rests, and a limiting surface extending downward from the support surface. The support surface and the limiting surface extend radially outward from the axis and are respectively sandwiched at an angle not greater than 90 degrees. The predetermined angle range of the eccentric protrusion rotating around the axis is greater than 30 degrees and less than 90 degrees.

[0014] The automatic lifting arm device of this utility model includes a limiting part connected to the eccentric protrusion and spaced apart from the rotating main rod. The rotating main rod and the limiting part extend along the axis. The rotating main rod, the eccentric protrusion and the limiting part together define a groove. The swinging part of the lifting shaft is limited to the groove and has a downward-facing swinging surface. The swinging part of the lifting shaft includes a main plate area extending downward from the lifting main rod and having the swinging surface, and an extension plate area extending downward from the main plate area. The swinging surface is exposed in the extension plate area, and the extension plate area has an extension surface facing the limiting surface of the eccentric protrusion.

[0015] The automatic arm-raising device of this utility model includes a sensing module comprising a cam connected to the drive mechanism and capable of being rotated by the stepper motor, and a spring sheet assembly. The spring sheet assembly includes a first conductive sheet and a second conductive sheet mounted on the base. The first conductive sheet has a constant elastic force toward the second conductive sheet and can be detached and elastically supported against the cam. The first conductive sheet and the second conductive sheet can switch between a first state and a second state. In the first state, the first conductive sheet elastically supports the cam, and the first conductive sheet and the second conductive sheet are electrically disconnected from each other to generate the first sensing signal. In the second state, the first conductive sheet is separated from the cam, and the first conductive sheet and the second conductive sheet are electrically connected to generate the second sensing signal.

[0016] In the automatic arm lifting device of this utility model, the cam rotates synchronously with the rotating shaft assembly. When the eccentric protrusion is in the lowering state and drives the lifting shaft to the lowered position, the first conductive plate elastically abuts against the cam and is in the first state. When the eccentric protrusion is in the lifting state and drives the lifting shaft to the raised position, the first conductive plate does not contact the cam and is in the second state.

[0017] The automatic arm raising device of this utility model further includes a control key connected to the control module. When the control key is operated, it transmits a control signal to the control module. The control module is triggered by the control signal to start the stepper motor and drive the eccentric protrusion to switch between the raised state and the lowered state.

[0018] The automatic arm raising device of this utility model is triggered when the control module receives the control signal and the first sensing signal, controlling the stepper motor to rotate in a first rotation direction, driving the eccentric protrusion to move the lifting shaft from the lowering position to the raising position. When the control module receives the control signal and the second sensing signal, it is triggered to control the stepper motor to rotate in a second rotation direction opposite to the first rotation direction, driving the eccentric protrusion to move the lifting shaft from the raising position to the lowering position.

[0019] The automatic tonearm lifting device of this utility model further includes a main control module disposed on the turntable. The control module is signal connected to the main control module and is adapted to be triggered by a trigger signal of the main control module when the main control module receives a termination signal from the tonearm, thereby controlling the stepper motor to rotate in a first rotation direction, driving the eccentric protrusion to move the lifting shaft from the lowered position to the raised position.

[0020] The automatic arm lifting device of this utility model has a stepper motor signal connected to the control module and can be controlled by the control module to start. The stepper motor drives the rotating shaft assembly to rotate within an angle range of 30 degrees to 60 degrees.

[0021] The beneficial effects of this invention are as follows: Utilizing the design of the stepper motor and the eccentric protrusion, the lifting shaft can be moved to the lowered and raised positions during rotation, which is quite novel. Furthermore, by using the stepper motor to directly drive the eccentric protrusion to rotate, the problems of motor idling and excessive rotation leading to energy waste can be improved. Attached Figure Description

[0022] Figure 1 This is a perspective view illustrating an embodiment of the automatic arm lifting device of this utility model applicable to a record player;

[0023] Figure 2 It is an incomplete perspective view illustrating that this embodiment is applicable to a tonearm of the turntable;

[0024] Figure 3 This is an exploded three-dimensional view illustrating this embodiment;

[0025] Figure 4 It is an incomplete sectional view, illustrating that in this embodiment, an eccentric protrusion is in a lowered state; a lifting shaft is in a lowered position; and a first conductive sheet and a second conductive sheet of a spring sheet assembly are in a first state.

[0026] Figure 5 This is an incomplete cross-sectional view from another angle, illustrating this embodiment;

[0027] Figure 6 It is similar Figure 4 The view illustrates that the eccentric protrusion of this embodiment is in a raised state; the lifting shaft is in a raised position; and the first conductive sheet and the second conductive sheet of the spring assembly are in a second state. Detailed Implementation

[0028] See Figures 1 to 2 This is an embodiment of the automatic arm lifting device 10 of this utility model, applicable to a turntable 9. The turntable 9 mainly includes a housing 91, a tonearm 92 disposed on the housing 91 and equipped with a stylus 93, a platter 94 rotatably disposed on the housing 91 for carrying a record (not shown), and a main control module 95 disposed on the housing 91. The main control module 95 is signal-connected to the tonearm 92 and the platter 94, and can control the rotation of the platter 94 and process audio signals. Since the main structure of the turntable 9 is familiar to those skilled in the art and is not the focus of this invention, it will not be described in detail here.

[0029] See Figure 1 , Figure 3 and Figure 4 The automatic arm lifting device 10 includes a base 1 disposed on the housing 91, a drive mechanism 2 disposed on the base 1, an arm lifting mechanism 3 disposed on the base 1, a control key 5 disposed on the housing 91, a sensing module 4 signal-connected to the main control module 95, and a control module 6 disposed on the housing 91. The control module 6 is signal-connected to the drive mechanism 2, the arm lifting mechanism 3, and the control key 5.

[0030] The base 1 includes a first base 11 mounted in the housing 91, and a second base 12 screwed to the front side of the first base 11. The first base 11 has a first plate 111 mounted on the top side of the housing 91, and a second plate 112 extending downward from the leading edge of the first plate 111. The second base 12 includes a hollow cylindrical tube 121. The cylindrical tube 121 forms a first through hole 122 extending back and forth along an axis M.

[0031] See Figures 3 to 5 The drive mechanism 2 includes a stepper motor 21 mounted on the first base 11 and a rotating shaft assembly 22 mounted on the stepper motor 21. The stepper motor 21 is signal-connected to the control module 6 and can be controlled to rotate in a first rotation direction T1 (e.g., ...). Figure 4 ) rotates, and a second rotation direction T2 is opposite to the first rotation direction T1 (e.g. Figure 6 The rotating shaft assembly 22 includes an output shaft 221 connected to a rotating shaft 211 of the stepper motor 21, and a rotating shaft 222 connected to the output shaft 221. When the stepper motor 21 is controlled, the stepper motor 21 drives the rotating shaft assembly 22 to rotate gradually according to a predetermined step angle.

[0032] In this way, the output shaft 221 and the rotating shaft 222 can be driven by the stepper motor 21 to rotate synchronously. The stepper motor 21 can drive the rotating shaft assembly 22 to rotate at an angle of 45 degrees. Therefore, the rotating shaft assembly 22 and the stepper motor 21 do not need to be connected with additional gears and / or belts to rotate slowly.

[0033] The rotating shaft 222 includes a rotating main shaft portion 223 that is inserted into the output shaft 221 and connected to the stepper motor 21, an eccentric protrusion portion 224, and a limiting portion 225.

[0034] The rotating main rod portion 223 is generally cylindrical and includes an end face 226 that is planar and faces away from the output rotating shaft 221. The eccentric protrusion portion 224 protrudes from the end face 226 and includes an upward-facing support surface 227 that can support the swing surface 325 of the lifting shaft 32, and a limiting surface 228 that extends downward from the support surface 227. The support surface 227 and the limiting surface 228 extend radially outward from the axis M and are positioned at an angle A not greater than 90 degrees between them.

[0035] The limiting part 225 is cylindrical and integrally connected to the eccentric protrusion part 224, and is spaced apart from the rotating main rod part 223. The rotating main rod part 223 and the limiting part 225 extend along the axis M, and the rotating main rod part 223, the eccentric protrusion part 224, and the limiting part 225 together define a groove 229. In this embodiment, the projection of the eccentric protrusion part 224 in the direction of the axis M is located in the projection of the rotating main rod part 223, and forms a fan shape with a 90-degree angle. The shapes of the eccentric protrusion part 224 and the groove 229 in the direction of the axis M together form a circle (e.g., ...). Figure 4 (As shown).

[0036] See Figure 4 and Figure 6 When the rotating shaft assembly 22 rotates, the eccentric protrusion 224 rotates around the axis M, and is in a raised state relative to the base 1 (e.g., Figure 6 ) and a descending state (such as Figure 4 The eccentric protrusion 224 is positioned at a first height H1 relative to the bottom edge of the first seat 11 during the raised state, and at a second height H2 relative to the bottom edge of the first seat 11 during the lowered state. The first height H1 is greater than the second height H2.

[0037] In this embodiment, the rotating shaft assembly 22 is driven to rotate 45 degrees at a time, causing the eccentric protrusion 224 to rotate 45 degrees around the axis. In some embodiments, the step angle range of the stepper motor 21 can be set. Since the rotating shaft assembly 22 is driven to rotate synchronously by the stepper motor 21, the eccentric protrusion 224 can rotate synchronously around the axis M within a predetermined angle range. In some embodiments, the predetermined angle range of the eccentric protrusion 224 around the axis is greater than 0 degrees and less than 180 degrees. In some embodiments, the predetermined angle α of the eccentric protrusion 224 around the axis M is greater than 30 degrees and less than 90 degrees. In some embodiments, the angle by which the stepper motor 21 drives the rotating shaft assembly 22 to rotate can be from 30 degrees to 60 degrees, causing the predetermined angle α of the eccentric protrusion 224 around the axis M to be greater than 30 degrees and less than 60 degrees.

[0038] See Figures 3 to 5The lifting mechanism 3 includes a fixed sleeve 31 installed on the base 1, a lifting shaft 32 that can move up and down through the fixed sleeve 31, and a support platform 33 connected to a top end of the lifting shaft 32.

[0039] The fixing sleeve 31 passes through the cylindrical tube 121 of the second base 12 and is fixed to the cylindrical tube 121 by a hexagonal fixing cap 34 (e.g., a hexagonal nut). The fixing sleeve 31 has a second through hole 311. The second through hole 311 corresponds to the position of the first through hole 122 of the cylindrical tube 121 and also extends back and forth along the axis M.

[0040] The rotating shaft 222 is rotatably inserted through the first through hole 122 of the cylindrical tube 121 and the second through hole 311 of the fixed sleeve 31, such that the rotating main shaft portion 223 and the limiting portion 225 of the rotating shaft 222 are respectively limited to the rear and front sides of the second through hole 311. The eccentric protrusion portion 224 is located in the fixed sleeve 31, and the lifting shaft 32 rests against the eccentric protrusion portion 224.

[0041] The lifting shaft 32 includes a lifting main shaft 321 connected to the support platform 33 at its top end, and a resting portion 322 extending downward from the lifting main shaft. The resting portion 322 is generally inverted "L"-shaped and includes a main plate area 323 extending downward from a bottom end of the lifting main shaft 321 opposite to the support platform 33, and an extension plate area 324 extending downward from the right bottom end of the main plate area 323. The main plate area 323 includes a resting surface 325 resting on the abutment surface 227 of the eccentric protrusion 224. The resting surface 325 faces downward and is exposed in the extension plate area 324. The extension plate area 324 has an extension surface 326 facing the limiting surface 228 of the eccentric protrusion 224. In this way, the swinging part 322 of the lifting shaft 32 is substantially fitted into the eccentric protrusion 224 and confined in the groove 229.

[0042] The lifting shaft 32 can move up and down relative to the fixed sleeve 31 between a raised position and a lowered position. When the eccentric protrusion 224 is in the lowered state, the lifting shaft 32, which rests against the eccentric protrusion 224, is in a lowered position. When the eccentric protrusion 224 is in the raised state, the lifting shaft 32, which rests against the eccentric protrusion 224, is in a raised position. Therefore, when the lifting shaft 32 is in the raised position, the height of the support platform 33 is higher than the height of the support platform 33 in the lowered position, allowing the tonearm 92 (e.g., Figure 2 (As shown) is placed on it. When the support platform 33 is in the lowered position, the support platform 33 is positioned below the tonearm 92 at intervals.

[0043] The sensing module 4 includes a cam 41 extending radially outward from the output shaft 221 of the drive mechanism 2, and a spring assembly 42 mounted on the base 1 and signal-connected to the main control module 95 of the turntable 9. The cam 41 can be driven to rotate by the stepper motor 21 and rotate synchronously with the eccentric protrusion 224. The spring assembly 42 includes a first conductive plate 421 and a second conductive plate 422 mounted on the first base 11. The first conductive plate 421 includes a long, flat, conductive first plate body 423, a first conductive block 424 protruding from the side of the first plate body 423 toward the second conductive plate 422, and an elastic support block 425 connected to the top side of the first plate body 423. The first plate body 423 of the first conductive plate 421 has a constant elastic force toward the second conductive plate 422, so that the elastic support block 425 can be moved away from and elastically support the cam 41. The second conductive sheet 422 includes a long, sheet-shaped, conductive second sheet body 426 and a second conductive block 427 protruding from the side of the second sheet body 426 toward the first conductive sheet 421. The second conductive block 427 can detachably contact the first conductive block 424, and can be electrically connected to each other.

[0044] See Figure 4 and Figure 6 The first conductive sheet 421 and the second conductive sheet 422 can be in a first state (such as...) Figure 4 ) and a second state (such as Figure 6 The system transitions between states. In the first state, the elastic support block 425 elastically abuts against the cam 41, and the first conductive block 424 and the second conductive block 427 are separated from each other, so that the first conductive sheet 421 and the second conductive sheet 422 are not electrically connected to each other, thereby generating a first sensing signal that can be transmitted to the control module 6. In the second state, the first conductive sheet 421 is separated from the cam 41, and the first conductive block 424 and the second conductive block 427 are in contact with each other, so that the first conductive sheet 421 and the second conductive sheet 422 are electrically connected, thereby generating a second sensing signal that can be transmitted to the control module 6.

[0045] Therefore, the sensing module 4 can sense the rotation state of the rotating shaft assembly 22 of the drive mechanism 2 in the first state (such as...). Figure 4 ) and the second state (such as Figure 6 The eccentric protrusion 224 is in the lowered state, and the cam 41 pushes the first conductive plate 421, so that the sensing module 4 is in the first state and generates the first sensing signal; when the eccentric protrusion 224 is in the raised state, the cam 41 separates from the first conductive plate 421, so that the sensing module 4 is in the second state and generates the second sensing signal.

[0046] See Figure 1 , Figure 3 The control key 5 is connected to the control module 6 and is mounted on the housing 91 of the turntable 9. When the control key 5 is operated, it transmits a control signal to the control module 6. The control module 6 is located on the housing 91 of the turntable 9 and is connected to the main control module 95 of the turntable 9.

[0047] See Figure 1 , Figure 3 , Figure 4 and Figure 6 The control module 6 can be triggered by the control signal to start the stepper motor 21, thereby causing the eccentric protrusion 224 to move from the raised state (e.g., Figure 6 ) transition to this descending state (e.g. Figure 4 (This can be done by) transitioning from the descending state to the rising state. In this embodiment, the control module 6 and the main control module 95 are integrated on the same circuit board, and the control module 6 is a controller or a processor. In other embodiments, the control module 6 and the main control module 95 can be located at different positions on the housing 91.

[0048] More specifically, when the control module 6 receives the control signal and the first sensing signal, it is triggered to control the stepper motor 21 to rotate in the first rotation direction T1, driving the eccentric protrusion 224 from the lowering state to the raising state, thereby moving the lifting shaft 32 from the lowering position to the raising position, and the tonearm 92 can be raised using the support platform 33; when the control module 6 receives the control signal and the second sensing signal, it is triggered to control the stepper motor 21 to rotate in the second rotation direction T2, driving the eccentric protrusion 224 to move the lifting shaft 32 from the raising position to the lowering position, and the tonearm 92 can be lowered using the support platform 33.

[0049] On the other hand, when the stylus 93 of the tonearm 92 reads the end of the groove (not shown), it generates a stop signal indicating the end of the track and transmits the stop signal to the main control module 95. The main control module 95 is triggered by the stop signal and generates a corresponding trigger signal, which is then transmitted to the control module 6. At this time, the control module 6 is triggered to control the stepper motor 21 to rotate in the first rotation direction T1, driving the eccentric protrusion 224 to move the lifting shaft 32 from the lowered position to the raised position, thereby raising the tonearm 92 located on the support platform 33. Specifically, when the tonearm 92 moves to the groove corresponding to the end of the track, the main control module 95 receives an automatic stop signal from a light sensor (not shown, e.g., a light cutoff device) installed on the turntable 9, which serves as the stop signal. Then, the main control module 95 transmits the trigger signal to the control module 6 to start the stepper motor 21 to rotate.

[0050] When using the automatic lifting arm device 10, the eccentric protrusion 224 can be controlled to be in the lifted state (e.g., Figure 6 This allows the lifting shaft 32 to be initially positioned in the raised position. At this time, the tonearm 92 can be placed on the support platform 33 and positioned at intervals above the record. The sensing module 4 is in the second state and transmits the second sensing signal to the control module 6.

[0051] Next, the control signal is generated by manipulating the control key 5. The control module 6 is triggered when it simultaneously receives the control signal and the second sensing signal, causing the stepper motor 21 to rotate, driving the rotating shaft assembly 22 to rotate. This causes the eccentric protrusion 224 to rotate around the axis within a predetermined angle, transitioning it to the lowered state relative to the base 1. This moves the lifting shaft 32 from the raised position to the lowered position. Therefore, the stylus 93 of the tonearm 92 can read the grooves of the rotating record and transmit the signal to the main control module 95, converting it into analog audio, which is then amplified and played by the speaker. Simultaneously, as the rotating shaft assembly 22 rotates, it also drives the cam 41 of the sensing module 4 to rotate synchronously to the first state, causing the sensing module 4 to generate the first sensing signal and transmit it to the control module 6. The control module 6 then analyzes and determines that the lifting shaft 32 is in the lowered position and records it.

[0052] When the main control module 95 receives a termination signal generated by the stylus 93 of the tonearm 92 reading the end point of the groove on the record (not shown), it generates a trigger signal to the control module 6. The control module 6 is triggered upon simultaneously receiving the trigger signal and the first sensing signal, and controls the stepper motor 21 to rotate, thereby driving the eccentric protrusion 224 to switch to the raised state, causing the lifting shaft 32 to move to the raised position. In this way, the tonearm 92 is raised and moved away from the record. Simultaneously, the sensing module 4 transmits the second sensing signal to the control module 6, enabling the control module 6 to analyze and determine that the lifting shaft 32 is in the raised position and record it. In some embodiments, after power-on, the control module 6 can first control and record that the lifting shaft 32 is in the lowered position as a "zero position." Once in the zero position, the lifting shaft 32 is then controlled to be in the raised position to protect the stylus 93.

[0053] Furthermore, the user can manually stop music playback by operating the control button 5 during record playback. The control signal and the first sensing signal are transmitted to the control module 6, triggering the control module 6 to control the stepper motor 21 to rotate. This also drives the eccentric protrusion 224 to the raised state, causing the lifting shaft 32 to lift the tonearm 92 and move it away from the record. Music stops when the stylus 93 of the tonearm 92 stops contacting the grooves of the record.

[0054] Since the rotation angle of the stepper motor 21 can be controlled to 45 degrees, and since the rotating shaft assembly 22 is directly connected to the stepper motor 21 and linked with one rotor (not shown) of the stepper motor 21, the automatic lifting arm device 10 does not require additional gears or belts, allowing the lifting shaft 32 to slowly rise and fall during operation. Because the lifting shaft 32 rises or falls by rotating the eccentric protrusion 224 of the rotating shaft assembly 22, and the rotation of the eccentric protrusion 224 is linked to the stepper motor 21, the wear and energy consumption caused by the idling of existing motors can be avoided. Furthermore, utilizing the design of the cam 41 and spring assembly 42 of the sensing module 4, the cam 41, linked to the eccentric protrusion 224, can sensitively sense whether the eccentric protrusion 224 is in a raised or lowered state. The presence or absence of energization of the spring assembly 42 generates a second sensing signal and a first sensing signal, respectively.

[0055] In summary, the automatic lifting arm device 10 of this utility model, utilizing the design of the stepper motor 21 and the eccentric protrusion 224, can be in a raised state with a first height H1 and a lowered state with a second height H2 during rotation, respectively driving the lifting shaft 32 to be in the lowered and raised positions, which is a very novel and innovative design. By using the stepper motor 21, which is set within a predetermined rotation range, to directly drive the eccentric protrusion 224 to rotate, the disadvantages of motor idling wear and energy waste are avoided. The design of the sensing module 4, corresponding to the eccentric protrusion 224 being in the lowered or raised state, respectively senses and generates the first sensing signal and the second sensing signal, which are very sensitive. Therefore, the purpose of this utility model is indeed achieved.

[0056] The above description is merely an embodiment of this utility model and should not be construed as limiting the scope of this utility model. Any simple equivalent changes and modifications made in accordance with the claims and description of this utility model shall still fall within the scope of this utility model.

Claims

1. An automatic tonearm lifting device, suitable for a turntable, and comprising a base suitable for mounting on the turntable, characterized in that: The automatic boom lifting device further includes a drive mechanism and a boom lifting mechanism. The drive mechanism includes a stepper motor mounted on the base and a rotating shaft assembly mounted on the stepper motor. The rotating shaft assembly includes a rotating main rod connected to the stepper motor and an eccentric protrusion. The rotating main rod includes an end face opposite to the stepper motor, and the eccentric protrusion extends from the end face. The rotating shaft assembly is driven to rotate by the stepper motor, allowing the eccentric protrusion to rotate around an axis within a predetermined angle range. The structure includes a fixed sleeve mounted on the base, a lifting shaft that can move up and down through the fixed sleeve, and a support platform connected to the top end of the lifting shaft. The lifting shaft rests against the eccentric protrusion. When the rotating shaft assembly rotates, the eccentric protrusion drives the lifting shaft to move up and down relative to the fixed sleeve between a raised position and a lowered position. The height of the support platform in the raised position is higher than the height of the support platform in the lowered position, so as to allow the tonearm to be placed on it.

2. The automatic arm-raising device according to claim 1, characterized in that: It also includes a sensing module and a control module. The sensing module is adapted to be connected to the control module and installed on the base. The sensing module senses the rotation state of the rotating shaft assembly of the drive mechanism and changes between a first state and a second state. In the first state, the sensing module generates a first sensing signal that is transmitted to the control module. In the second state, the sensing module generates a second sensing signal that is transmitted to the control module.

3. The automatic arm-raising device according to claim 2, characterized in that: When the rotating shaft assembly rotates, the eccentric protrusion relative to the base switches between a raised state at a first height and a lowered state at a second height, causing the lifting shaft to move up and down relative to the fixed sleeve between the raised and lowered positions. The first height is greater than the second height, and the predetermined angle range of the eccentric protrusion rotating around the axis is greater than 0 degrees and less than 180 degrees.

4. The automatic arm-raising device according to claim 3, characterized in that: The lifting shaft of the boom mechanism includes a lifting main shaft connected to the support platform, and a swing rest portion extending downward from the bottom end of the support platform in the opposite direction of the lifting main shaft portion. The swing rest portion includes a swing rest surface that rests against the eccentric protrusion portion.

5. The automatic arm-raising device according to claim 4, characterized in that: The eccentric protrusion of the rotating shaft assembly includes a support surface on which the lifting shaft rests, and a limiting surface extending downward from the support surface. The support surface and the limiting surface extend radially outward from the axis and are angled together at an angle not greater than 90 degrees. The predetermined angle range of the eccentric protrusion rotating around the axis is greater than 30 degrees and less than 90 degrees.

6. The automatic arm-raising device according to claim 5, characterized in that: The rotating shaft assembly of the drive mechanism also includes a limiting part connected to the eccentric protrusion and spaced apart from the rotating main rod. The rotating main rod and the limiting part extend along the axis. The rotating main rod, the eccentric protrusion, and the limiting part together define a groove. The swinging part of the lifting shaft is limited to the groove and has a downward-facing swinging surface. The swinging part of the lifting shaft includes a main plate area extending downward from the lifting main rod and having the swinging surface, and an extension plate area extending downward from the main plate area. The swinging surface is exposed in the extension plate area, and the extension plate area has an extension surface facing the limiting surface of the eccentric protrusion.

7. The automatic arm-raising device according to claim 3, characterized in that: The sensing module includes a cam connected to the drive mechanism and capable of being rotated by the stepper motor, and a spring assembly. The spring assembly includes a first conductive plate and a second conductive plate mounted on the base. The first conductive plate has a constant elastic force toward the second conductive plate and can be detached and elastically supported against the cam. The first conductive plate and the second conductive plate can switch between a first state and a second state. In the first state, the first conductive plate elastically supports the cam, and the first conductive plate and the second conductive plate are electrically disconnected from each other to generate the first sensing signal. In the second state, the first conductive plate is separated from the cam, and the first conductive plate and the second conductive plate are electrically connected to generate the second sensing signal.

8. The automatic arm-raising device according to claim 7, characterized in that: The cam rotates synchronously with the rotating shaft assembly. When the eccentric protrusion is in the lowering state and drives the lifting shaft to the lowered position, the first conductive plate elastically abuts against the cam and is in the first state. When the eccentric protrusion is in the lifting state and drives the lifting shaft to the raised position, the first conductive plate does not contact the cam and is in the second state.

9. The automatic arm-raising device according to claim 8, characterized in that: It also includes a control key connected to the control module. When the control key is operated, it transmits a control signal to the control module. The control module is triggered by the control signal to start the stepper motor and drive the eccentric protrusion to switch between the raised state and the lowered state.

10. The automatic arm-raising device according to claim 9, characterized in that: When the control module receives the control signal and the first sensing signal, it is triggered to control the stepper motor to rotate in the first rotation direction, driving the eccentric protrusion to move the lifting shaft from the lowered position to the raised position. When the control module receives the control signal and the second sensing signal, it is triggered to control the stepper motor to rotate in the second rotation direction opposite to the first rotation direction, driving the eccentric protrusion to move the lifting shaft from the raised position to the lowered position.

11. The automatic arm-raising device according to claim 9, characterized in that: It also includes a main control module installed in the turntable. The control module is connected to the main control module and is triggered by the trigger signal of the main control module when the main control module receives the termination signal from the tonearm. It controls the stepper motor to rotate in the first rotation direction, drives the eccentric protrusion to move the lifting shaft from the lowered position to the raised position.

12. The automatic arm-raising device according to claim 2, characterized in that: The stepper motor of the drive mechanism is connected to the control module and can be started by the control module. The stepper motor drives the rotating shaft assembly to rotate within an angle range of 30 degrees to 60 degrees.

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