Rotatable waist fixing device for playing electric guitar and electric bass

Abstract

The utility model belongs to the technical field of playing musical instrument fixing, and particularly relates to a rotatable waist fixing device for electric guitar and electric bass playing, which comprises a shell frame, an inner clamping assembly, a leg supporting assembly and an adjustable pressing assembly, vertical flanges are integrally arranged on two sides of the shell frame, the inner clamping assembly is arranged in the shell frame, and the leg supporting assembly is arranged in the shell frame. The leg supporting assembly is arranged on one side of the outer shell frame, and the adjustable pressing assembly is arranged on the vertical side, corresponding to the leg supporting assembly, of the outer shell frame and corresponds to the inner clamping assembly. According to the utility model, through the synergistic effect of the inner clamping assembly and the adjustable pressing assembly, the adjustable pressing assembly is utilized to realize stable fixation with the waist, and through the cooperation of the inner clamping assembly and the installation assembly, the rotation function is realized, so that the electric guitar or the electric bass can perform 360-degree unobstructed rotation with the waist of a player as the axis; the problem that position switching is delayed due to constraint of the shoulder strap in the fast playing process is solved, the rotating action and the playing skill are seamlessly connected, and the performance effect is improved.

Description

Technical Field

[0001] This utility model belongs to the field of musical instrument fixing technology, specifically relating to a rotatable waist fixing device for playing electric guitars and electric basses. Background Technology

[0002] In traditional playing, electric guitars or basses are typically suspended in front of the player via shoulder straps. While this method ensures basic instrument stability, it severely restricts the player's performance freedom. Especially in genres like rock and metal that require strong stage presence, players often need to rotate the instrument to enhance the visual impact of their performance or to achieve smooth transitions between playing positions. However, with traditional shoulder straps, instrument rotation is physically limited by the straps wrapping around the body, typically allowing only a limited rotation of 90-180 degrees. Furthermore, the straps are prone to twisting and tangling after rotation, affecting the continuity of subsequent playing movements and potentially causing the instrument to fall uncontrollably. In addition, during high-speed passages requiring alternating hand positions, traditional methods fail to provide a stable pivot point, making it difficult for the player to precisely control the rotation angle and speed, severely impacting improvisational stage performance. Therefore, this invention proposes a rotatable waist support device for electric guitar and bass playing to solve these problems. Utility Model Content

[0003] The purpose of this invention is to provide a rotatable waist support device for playing electric guitars and electric basses, which can solve the above-mentioned technical problems.

[0004] The specific technical solution adopted by this utility model is as follows:

[0005] This utility model provides a rotatable waist fixing device for playing electric guitars and electric basses, including an outer frame, an inner clamping component, a leg support component, and an adjustable clamping component. The outer frame has vertical flanges integrally provided on both sides. The inner clamping component is disposed inside the outer frame. The leg support component is disposed on one side of the outer frame. The adjustable clamping component is disposed on the vertical side of the outer frame corresponding to the leg support component and is corresponding to the inner clamping component.

[0006] The inner clamping assembly includes a bearing pressure plate, a movable clamping plate, an outer pressure plate, and a locking pin. A flange bearing is installed through the bottom plate of the outer casing frame. The bearing pressure plate is located inside the outer casing frame and is fitted onto the flange bearing. The movable clamping plate movably abuts against the side of the bearing pressure plate, and the outer pressure plate abuts against the side of the movable clamping plate. A fastening screw is installed on the bottom plate of the outer casing frame, and the fastening screw passes through the bearing pressure plate and the movable clamping plate and is threadedly connected to the outer pressure plate. A rivet nut is fitted onto the movable clamping plate through an opening, and the rivet nut is screwed onto the fastening screw and presses against the surface of the bearing pressure plate. The locking pin passes through the flange bearing and is fitted into a positioning hole, and the positioning hole is opened through the outer pressure plate. The outer casing frame is correspondingly provided with a mounting assembly for connecting to an electric guitar or electric bass.

[0007] The adjustable clamping assembly includes an elastic frame plate and a clamping elastic element. Two vertical ear plates are provided on opposite sides of the two vertical flanges. Long screws are threaded through the two vertical ear plates and the vertical flanges. The vertical ear plates abut against the outer surface of the inner cover. The clamping elastic element is sleeved on the long screw and is located between the elastic frame plate and the inner cover. The clamping elastic element is a torsion spring, which uses the torsion spring's counter-pushing effect to maintain pressure on the elastic frame plate. The outer surface of the inner cover elastically holds a belt pressure plate for preventing belt disengagement. The belt pressure plate is integrally located on the side of the elastic frame plate away from the clamping elastic element.

[0008] Preferably, an adjustment hole is provided through the vertical flange, and a push-pull ear plate is slidably fitted inside the adjustment hole. The push-pull ear plate is integrally fixed to the other side of the movable plate. The mounting assembly includes an inner pin, a bridge plate, and wood screws. The inner pin is fitted through the bridge plate and fixedly connected with a locking pin. The wood screws are threaded through the reserved holes on both sides of the bridge plate and installed on the side of the electric guitar or electric bass.

[0009] Preferably, the vertical flange is provided in two pieces, and an embedded cover is embedded between the two pieces. Vertical baffles are provided on both sides of the embedded cover. The embedded cover and the two baffles wrap around the inner sides of the two vertical flanges of the outer frame. External protrusions are provided on the other two sides of the embedded cover, and the external protrusions are engaged with the notches opened on the surface of the vertical flange.

[0010] Preferably, the leg support assembly includes a leg support arm, an adjusting nut, and an eccentric locking handle. Two movable ear plates are fitted between the two vertical flanges, and the two movable ear plates are respectively fixed on both sides of the leg support arm. The screw on the eccentric locking handle passes through the vertical flanges and the movable ear plates and is threadedly connected to the adjusting nut. Friction pads are provided on opposite sides of the two movable ear plates, and the friction pads are fitted onto the screw on the eccentric locking handle and located between the adjusting nut and the movable ear plates.

[0011] Preferably, the lower side of the leg support arm is provided with a support arm crossbar, a square root screw and a butterfly nut. The square root screw passes through the leg support arm and the support arm crossbar and is threadedly connected to the butterfly nut. The support arm crossbar is configured with an inwardly concave arc shape.

[0012] Preferably, the sides of the movable retaining plate and the outer pressure plate inside the outer casing are provided with a thrust elastic element. The two sides of the thrust elastic element are respectively sleeved on the fixed protrusion and the movable protrusion. The fixed protrusion is fixed to the side of the bearing pressure plate, and the movable protrusion is fixed to one side of the movable retaining plate.

[0013] Preferably, the outer wall of the locking pin is provided with an annular groove at the corresponding position of the movable plate, and the movable plate is provided with a displacement hole that cooperates with the locking pin. Under the elastic force of the push elastic element, the positioning hole and the displacement hole of the outer pressure plate form an interlocking structure and are locked into the annular groove. The side of the movable plate opposite to the movable protrusion is provided with a movable opening, and the movable opening is sleeved on the outer periphery of one of the fastening screws.

[0014] Preferably, the annular groove on the locking pin and the displacement hole on the movable plate form a rotatable insertion fit, and the sliding displacement of the push-pull ear plate in the adjusting movable hole is equal to the moving displacement of the fastening screw in the movable opening.

[0015] The beneficial effects are:

[0016] 1. This utility model utilizes the synergistic effect of the inner clamping component and the adjustable clamping component to achieve a stable fixation to the waist. At the same time, the inner clamping component and the mounting component work together to achieve a rotation function, allowing the electric guitar or electric bass to rotate 360° without obstruction around the player's waist as the axis. This solves the problem of delayed position switching caused by shoulder strap restraint during fast playing, and makes the rotation action and playing technique seamlessly connected, truly achieving a performance effect of unity between the player and the instrument.

[0017] 2. This utility model, through the cooperation of the inner card component and the mounting component, enables the quick installation and disassembly of electric guitars or electric basses, significantly improving ease of use.

[0018] 3. This utility model, through the design of the leg support component, utilizes the cooperation between the leg support arm and the support arm crossbar to provide tilt angle support for the rotating electric guitar or electric bass, which can not only adapt to the needs of players with different body shapes, but also avoid interference with the face and legs when rotating 360°. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the main structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the leg support arm in the unfolded and locked state of this utility model.

[0021] Figure 3 This is a schematic diagram of the internal cross-sectional structure of the outer shell when the leg support arm of this utility model is unfolded;

[0022] Figure 4 This is an exploded structural diagram of the various parts of this utility model;

[0023] Figure 5 This is a schematic diagram of the leg support arm and leg support crossbar in a relaxed state according to this utility model.

[0024] Figure 6 This is a schematic diagram of the installation state of this utility model with an electric guitar or electric bass.

[0025] The attached diagram lists the components represented by each number as follows:

[0026] 1. Flange bearing; 2. Bearing pressure plate; 2a. Fixed protrusion; 3. Movable clamping plate; 3a. Movable protrusion; 3b. Displacement hole; 3c. Movable opening; 4. Outer pressure plate; 4a. Positioning hole; 5. Fastening screw; 6. Inner pin; 7. Elastic frame plate; 7a. Vertical ear plate; 7b. Belt pressure plate; 8. Clamping elastic element; 9. Leg support arm; 9a. Movable ear plate; 10. Support arm crossbar; 11. Butterfly nut; 12. Reverse push elastic element; 13. Outer frame; 13a. Vertical flange; 13b. Adjustment hole; 13c. Notch; 14. Friction pad; 15. Adjusting nut; 16. Square root screw; 17. Push-pull ear plate; 18. Inset cover; 18a. Outer protrusion; 19. Eccentric lock handle; 20. Bridge plate; 21. Locking pin; 21a. Ring groove; 22. Wood screw. Detailed Implementation

[0027] To make the objectives and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of this utility model and does not strictly limit the scope of protection specifically claimed by this utility model.

[0028] like Figure 1-6 As shown, a rotatable waist fixing device for playing electric guitar and electric bass includes an outer frame 13, an inner clamping component, a leg support component, and an adjustable clamping component. Vertical flanges 13a are integrally provided on both sides of the outer frame 13. The inner clamping component is disposed inside the outer frame 13. The leg support component is disposed on one side of the outer frame 13. The adjustable clamping component is disposed on the vertical side of the outer frame 13 corresponding to the leg support component and is corresponding to the inner clamping component.

[0029] The inner clamping assembly includes a bearing pressure plate 2, a movable clamping plate 3, an outer pressure plate 4, and a locking pin 21. A flange bearing 1 is installed through the bottom plate of the outer frame 13. The bearing pressure plate 2 is located inside the outer frame 13 and is fitted onto the flange bearing 1. The movable clamping plate 3 is movably pressed against the side of the bearing pressure plate 2, and the outer pressure plate 4 is pressed against the side of the movable clamping plate 3. A fastening screw 5 is installed on the bottom plate of the outer frame 13, and the fastening screw 5 passes through the bearing pressure plate 2 and the movable clamping plate 3 and is threadedly connected to the outer pressure plate 4. The movable clamping plate 3 is fitted with a rivet nut through an opening, and the rivet nut is screwed onto the fastening screw 5 and presses against the surface of the bearing pressure plate 2. The locking pin 21 passes through the flange bearing 1 and is fitted into the positioning hole 4a, and the positioning hole 4a is opened through the outer pressure plate 4. The outer frame 13 is correspondingly provided with a mounting assembly for connecting to an electric guitar or electric bass.

[0030] The adjustable clamping assembly includes an elastic frame plate 7 and a clamping elastic element 8. Two vertical ear plates 7a are provided on opposite sides of two vertical flanges 13a. Long screws are threaded through the two vertical ear plates 7a and the vertical flanges 13a. The vertical ear plates 7a abut against the outer surface of the inner cover 18. The clamping elastic element 8 is sleeved on the long screw and is located between the elastic frame plate 7 and the inner cover 18. The clamping elastic element 8 is a torsion spring. The pressure on the elastic frame plate 7 is maintained by the torsion spring's counter-pushing effect. The outer surface of the inner cover 18 elastically holds a belt pressure plate 7b to prevent the belt from slipping off. The belt pressure plate 7b is integrally located on the side of the elastic frame plate 7 away from the clamping elastic element 8. This design allows the belt pressure plate 7b to open by pressing the elastic frame plate 7, making it easy to put the belt on and fix it to the user's waist.

[0031] As an optional implementation, an adjustment hole 13b is provided through the vertical flange 13a, and a push-pull ear plate 17 is slidably fitted inside the adjustment hole 13b. The push-pull ear plate 17 is integrally fixed on the other side of the movable card plate 3. The mounting components include an inner pin 6, a bridge plate 20, and a wood screw 22. The inner pin 6 is fitted through the bridge plate 20 and is fixedly connected to the locking pin 21. The wood screw 22 is threaded through the reserved holes on both sides of the bridge plate 20 and installed on the side of the electric guitar or electric bass. This design allows the electric guitar or electric bass to be installed with the bridge plate 20 via the wood screw 22. The bridge plate 20 and the locking pin 21 cooperate to achieve a quick insertion and connection operation with the inner card assembly, which is convenient for fixed use during performance.

[0032] See attached document Figure 4The vertical flanges 13a are configured as two pieces, and an embedded cover 18 is embedded between the two pieces. Vertical baffles are provided on both sides of the embedded cover 18. The embedded cover 18 and the two baffles wrap around the inner side of the two vertical flanges 13a of the outer frame 13. External protrusions 18a are provided on the other two sides of the embedded cover 18, and the external protrusions 18a are engaged with the recesses 13c opened on the surface of the vertical flanges 13a. The embedded cover 18 is tightly embedded between the two vertical flanges 13a by mechanical pressing, and the external protrusions 18a are simultaneously tightly embedded in the recesses 13c to improve the fixing effect of the embedded cover 18.

[0033] See attached document Figure 5 The leg support assembly includes a leg support arm 9, an adjusting nut 15, and an eccentric locking handle 19. Two movable ear plates 9a are fitted between two vertical flanges 13a and fixed to both sides of the leg support arm 9. The screw on the eccentric locking handle 19 passes through the vertical flanges 13a and the movable ear plates 9a and is threaded to the adjusting nut 15. Friction pads 14 are provided on opposite sides of the two movable ear plates 9a and are fitted onto the screw on the eccentric locking handle 19 and located between the adjusting nut 15 and the movable ear plates 9a. The eccentric locking handle 19, the adjusting nut 15, and the friction pads 14 are an assembly of a folding handle clamping bolt and nut. This design allows the leg support arm 9 to adjust its angle by cooperating with the eccentric locking handle 19 and the adjusting nut 15, adapting to the needs of players with different body shapes and avoiding interference with the face and legs during 360° rotation.

[0034] Furthermore, the lower side of the leg support arm 9 is provided with a support arm crossbar 10, a square screw 16, and a butterfly nut 11. The square screw 16 passes through the leg support arm 9 and the support arm crossbar 10 and is threadedly connected to the butterfly nut 11. The butterfly nut 11 cooperates with the square screw 16 to realize the rotation adjustment and fixation of the support arm crossbar 10, thereby supporting the weight of the electric guitar or electric bass. The support arm crossbar 10 is set with an inward arc shape. This design allows the support arm crossbar 10 to rest against the root of the thigh to support the weight of the electric guitar or electric bass, forming an upward tilt playing angle.

[0035] Furthermore, the movable retaining plate 3 and the outer pressure plate 4 inside the outer casing 13 are provided with a push-back elastic member 12. The two sides of the push-back elastic member 12 are respectively sleeved on the fixed protrusion 2a and the movable protrusion 3a. The fixed protrusion 2a is fixed on the side of the bearing pressure plate 2, and the movable protrusion 3a is fixed on one side of the movable retaining plate 3. The push-back elastic member 12 is a spring, which can push the fixed protrusion 2a away from the movable protrusion 3a at all times, thereby driving the movable plate 3 to rotate around another fastening screw 5 as the center, thereby driving the movable retaining plate 3 to lock and restrict the locking pin 21.

[0036] Furthermore, an annular groove 21a is provided on the outer wall of the locking pin 21 at the corresponding position of the movable plate 3. The movable plate 3 is provided with a displacement hole 3b that cooperates with the locking pin 21. Under the elastic force of the push elastic member 12, the movable plate 3 causes the positioning hole 4a of the outer pressure plate 4 and the displacement hole 3b to form an interlocking structure and be inserted into the annular groove 21a. The movable plate 3 is provided with a movable opening 3c on the side opposite to the movable protrusion 3a. The movable opening 3c is sleeved on the outer periphery of one of the fastening screws 5. By adjusting the displacement of the movable plate 3, the movable opening 3c and the fastening screw 5 form a dynamic cooperation space.

[0037] Furthermore, the annular groove 21a on the locking pin 21 and the displacement hole 3b on the movable plate 3 form a rotatable insertion fit. The sliding displacement of the push-pull ear plate 17 in the adjusting movable hole 13b is equal to the moving displacement of the fastening screw 5 in the movable opening 3c. Thus, when the push-pull ear plate 17 is pushed and adjusted, it drives the movable plate 3 to rotate around another fastening screw as the center, thereby driving the displacement hole 3b to release the annular groove 21a from the engagement.

[0038] Using the above structure, the steps are as follows:

[0039] 1. Steps for lumbar support:

[0040] 1.1 Pressing the elastic frame plate 7 on the adjustable clamping assembly causes the included angle between the belt pressure plate 7b and the inner cover 18 to widen;

[0041] 1.2 Insert the belt between the elastic frame plate 7 and the inner cover 18. After releasing the elastic frame plate 7, clamp the elastic element 8 (torsion spring) to push the belt pressure plate 7b to press the belt and prevent it from falling off.

[0042] 1.3 Secure the belt around the performer's waist.

[0043] 2. Leg support adjustment steps:

[0044] 2.1 Loosen the eccentric lock handle 19 on the leg support assembly to release the lock on the leg support arm 9;

[0045] 2.2 Adjust the angle of the leg support arm 9 to fit against the root of the thigh, tighten the eccentric lock handle 19, and press the movable ear plate 9a with the adjusting nut 15 to achieve a stable fixation.

[0046] 3. Instrument assembly steps:

[0047] 3.1 First, fix the bridge plate 20 to the locking pin 21 with the inner pin 6, and then use wood screws 22 to install the bridge plate 20 on the side of the electric guitar or electric bass.

[0048] 3.2 Insert the locking pin 21 into the flange bearing 1. At this time, the sleeve holes on the movable clamping plate 3 and the outer pressure plate 4 are automatically engaged in the annular groove 21a of the locking pin 21 under the action of the reverse elastic element 12 (spring), forming an axial limit.

[0049] 3.3 After installation, the electric guitar or bass can rotate freely 360° around the axis of flange bearing 1.

[0050] The above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. All standard parts used in this application can be purchased from the market, and can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts and embedded snap-fits that are mature in the prior art. The machinery, parts, and equipment all adopt conventional models in the prior art, and this application is mainly used to protect mechanical devices. Structures, devices, and operating methods not specifically described or explained in this utility model, unless otherwise specified or limited, are implemented according to conventional methods in the field.

Claims

1. A rotatable waist support device for playing electric guitars and electric basses, characterized in that: It includes an outer shell frame (13), an inner clamping assembly, a leg support assembly, and an adjustable clamping assembly. The outer shell frame (13) has vertical flanges (13a) integrally provided on both sides. The inner clamping assembly is disposed inside the outer shell frame (13). The leg support assembly is disposed on one side of the outer shell frame (13). The adjustable clamping assembly is disposed on the vertical side of the outer shell frame (13) corresponding to the leg support assembly and corresponding to the inner clamping assembly. The inner clamping assembly includes a bearing pressure plate (2), a movable clamping plate (3), an outer pressure plate (4), and a locking pin (21). A flange bearing (1) is installed through the bottom plate of the outer casing frame (13). The bearing pressure plate (2) is located inside the outer casing frame (13) and is fitted onto the flange bearing (1). The movable clamping plate (3) movably abuts against the side of the bearing pressure plate (2). The outer pressure plate (4) abuts against the side of the movable clamping plate (3). Fastening screws (5) are installed on the bottom plate of the outer casing frame (13). The thread (5) passes through the bearing pressure plate (2) and the movable clamping plate (3) and is threadedly connected to the outer pressure plate (4). The movable clamping plate (3) is fitted with a rivet nut through the opening, and the rivet nut is screwed on the fastening screw (5) and pressed on the surface of the bearing pressure plate (2). The locking pin (21) passes through the flange bearing (1) and is fitted in the positioning hole (4a), and the positioning hole (4a) is opened through the outer pressure plate (4). The outer frame (13) is correspondingly provided with a mounting component for connecting to an electric guitar or electric bass. The adjustable clamping assembly includes an elastic frame plate (7) and a clamping elastic element (8). Two vertical ear plates (7a) are provided on opposite sides of the two vertical flanges (13a). Long screws are sleeved through the two vertical ear plates (7a) and the vertical flanges (13a). The vertical ear plates (7a) abut against the outer surface of the inner cover (18). The clamping elastic element (8) is sleeved on the long screw and is located between the elastic frame plate (7) and the inner cover (18). The clamping elastic element (8) is a torsion spring. The pressure on the elastic frame plate (7) is maintained by the torsion spring's counter-pushing effect. The outer surface of the inner cover (18) elastically holds a belt pressure plate (7b) for limiting belt disengagement. The belt pressure plate (7b) is integrally located on the side of the elastic frame plate (7) away from the clamping elastic element (8).

2. The rotatable waist support device for playing electric guitars and electric basses according to claim 1, characterized in that: An adjustment hole (13b) is provided through the vertical flange (13a), and a push-pull ear plate (17) is slidably fitted inside the adjustment hole (13b). The push-pull ear plate (17) is integrally fixed on the other side of the movable card plate (3). The mounting assembly includes an inner pin (6), a bridge plate (20), and a wood screw (22). The inner pin (6) is fitted through the bridge plate (20) and fixedly connected with the locking pin (21). The wood screw (22) is threaded through the reserved holes on both sides of the bridge plate (20) and installed on the side of the electric guitar or electric bass.

3. The rotatable waist fixing device for playing electric guitars and electric basses according to claim 2, characterized in that: The vertical flange (13a) is configured as two pieces, and an embedded cover (18) is embedded between the two pieces. Vertical baffles are provided on both sides of the embedded cover (18). The embedded cover (18) and the two baffles wrap around the inner sides of the two vertical flanges (13a) of the outer frame (13). Outer protrusions (18a) are provided on the other two sides of the embedded cover (18), and the outer protrusions (18a) are engaged with the notches (13c) opened on the surface of the vertical flange (13a).

4. The rotatable waist support device for playing electric guitars and electric basses according to claim 3, characterized in that: The leg support assembly includes a leg support arm (9), an adjusting nut (15), and an eccentric lock handle (19). Two movable ear plates (9a) are fitted between the two vertical flanges (13a) and are respectively fixed on both sides of the leg support arm (9). The screw on the eccentric lock handle (19) passes through the vertical flange (13a) and the movable ear plate (9a) and is threaded to the adjusting nut (15). Friction pads (14) are provided on opposite sides of the two movable ear plates (9a), and the friction pads (14) are fitted on the screw on the eccentric lock handle (19) and located between the adjusting nut (15) and the movable ear plate (9a).

5. A rotatable waist support device for playing electric guitars and electric basses according to claim 4, characterized in that: The lower side of the leg support arm (9) is provided with a support arm crossbar (10), a square root screw (16) and a butterfly nut (11). The square root screw (16) passes through the leg support arm (9) and the support arm crossbar (10) and is threadedly connected to the butterfly nut (11).

6. A rotatable waist support device for playing electric guitars and electric basses according to claim 5, characterized in that: The movable retaining plate (3) and the outer pressure plate (4) inside the outer shell frame (13) are provided with a reverse thrust elastic element (12). The two sides of the reverse thrust elastic element (12) are respectively sleeved on the fixed protrusion (2a) and the movable protrusion (3a). The fixed protrusion (2a) is fixed on the side of the bearing pressure plate (2), and the movable protrusion (3a) is fixed on one side of the movable retaining plate (3).

7. A rotatable waist support device for playing electric guitars and electric basses according to claim 6, characterized in that: The outer wall of the locking pin (21) is provided with an annular groove (21a) corresponding to the position of the movable plate (3). The movable plate (3) is provided with a displacement hole (3b) that cooperates with the locking pin (21). Under the elastic force of the push elastic member (12), the positioning hole (4a) of the outer pressure plate (4) and the displacement hole (3b) form an interlocking structure and are inserted into the annular groove (21a). The movable plate (3) is provided with a movable opening (3c) on the side opposite to the movable protrusion (3a). The movable opening (3c) is sleeved on the outer periphery of one of the fastening screws (5).

8. A rotatable waist support device for playing electric guitars and electric basses according to claim 7, characterized in that: The annular groove (21a) on the locking pin (21) and the displacement hole (3b) on the movable plate (3) form a rotatable insertion fit. The sliding displacement of the push-pull ear plate (17) in the adjusting movable hole (13b) is equal to the movable displacement of the fastening screw (5) in the movable opening (3c).

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