CN115306803A - Adjustable support arm - Google Patents

Abstract

The invention relates to an adjustable supporting arm which comprises a front arm, a rear arm, a knob adjusting structure and a rear arm connecting block, wherein the rear arm connecting block is fixed on the front arm, the rear arm connecting block is connected to the rear arm by being inserted into a mounting hole, the knob adjusting structure is mounted at the tail end of the front arm, the elasticity is adjusted by rotating the knob adjusting structure, the knob adjusting structure makes a sound in the rotating process to provide sound feedback for a user, and the rear arm connecting block makes a sound when rotating in the mounting hole of the rear arm to provide sound feedback for the user. The adjustable supporting arm has the function of adjusting the force value by the knob, has various force value adjusting modes, and can be flexibly selected by a user to directly rotate the knob or rotate the knob by a tool. The supporting arm of the device also has a sound feedback function, and when the knob is rotated or the rear arm is rotated, the supporting arm can make a sound to remind a user of the current state and give sound feedback.

Description

adjustable support arm

technical field

The present invention relates to the field of mechanical structures, in particular to the field of support devices, in particular to an adjustable support arm.

Background technique

The support arm in the prior art usually adopts the method of adjusting the strength of the upper arm, usually using tools such as an Allen wrench. The support arm in the prior art does not have a control prompt sound when adjusting the strength or rotating the product angle, and cannot remind the user, which is very inconvenient. The support arm base of the support arm in the prior art is cumbersome to operate when using the preset and quick clamping functions, and is inconvenient to use.

Contents of the invention

The object of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide an adjustable support arm satisfying the requirements of simple structure, easy operation and wide application range.

In order to achieve the above object, the adjustable support arm of the present invention has the following structure:

The main feature of the adjustable support arm is that the adjustable support arm includes a forearm, a rear arm, a knob adjustment structure and a rear arm connection block, the knob adjustment structure is installed at the end of the forearm, and the adjustment structure is adjusted by rotating the knob. To adjust the elastic force, the rear arm connection block is fixed on the forearm, and the rear arm connection block is connected to the rear arm by being inserted into the mounting hole; the knob adjustment structure has a first sound feedback mechanism, and/or the The rear arm connection block has a second sound feedback mechanism, and the first sound feedback mechanism and/or the second sound feedback mechanism emit sound during rotation to provide sound feedback for the user.

Preferably, the knob adjustment structure includes an adjustment shaft, a knob, an adjustment screw and a gear. There is a notch inside the end of the forearm, the adjustment shaft is embedded in the notch, and the gear is sleeved on the adjustment shaft. Above, the adjustment shaft is connected to the adjustment screw, gear and knob, the adjustment shaft drives the gear to rotate, the knob and the adjustment screw are synchronized through the connection of the adjustment shaft, the knob is fastened on the forearm, and the rotation of the knob , adjust the elastic force by driving the adjusting screw to rotate through the adjusting shaft.

Preferably, the first sound feedback mechanism includes a steel ball, a spring and a set screw, and the set screw fixes the steel ball and the spring in the threaded hole of the forearm, and pushes against the teeth of the gear, and the knob rotates During the process, the adjusting screw is driven to rotate by the adjusting shaft, and the gear is driven to rotate by the adjusting shaft, and rubs against the steel ball to make a sound;

Alternatively, the first sound feedback mechanism includes a second pinball screw, the second pinball screw is fixed in the threaded hole of the forearm, and is pushed against the teeth of the gear. During the rotation of the knob, the adjustment shaft The adjusting screw is driven to rotate, and the gear is driven to rotate by the adjusting shaft, and rubs against the second pinball screw to make a sound.

Preferably, there is a gear at the bottom of the rear arm connecting block, and the second sound feedback mechanism includes a steel ball, a spring and a set screw. When the rear arm connecting block is inserted into the rear arm, the tightening The set screws screw the steel ball and spring in from the bottom of the rear arm, and snap into the gear of the rear arm connection block. When the rear arm connection block rotates in the hole of the rear arm, the steel ball and spring rub against the gear of the rear arm connection block and make a sound , providing user voice feedback;

Alternatively, the second sound feedback mechanism includes a second pinball screw, and when the rear arm connecting block is inserted into the rear arm, the second pinball screw is screwed in from the bottom of the rear arm and snapped into the rear arm In the gear of the connecting block, when the rear arm connecting block rotates in the hole of the rear arm, the friction between the pinball screw and the gear of the rear arm connecting block makes a sound, providing the user with sound feedback.

Preferably, the knob adjustment structure further includes a wrench, the top of the knob has an adjustment hole, one end of the wrench is inserted into the adjustment hole, and the knob is turned by turning the wrench.

Preferably, the adjustment shaft is a hexagonal shaft or a non-rotating shaft.

Preferably, the forearm includes a first forearm assembly and a second forearm assembly, the structures of the first forearm assembly and the second forearm assembly are similar, and the first forearm assembly and the second forearm assembly are combined to form the forearm , the first sound feedback mechanism is fixed on the threaded hole of the second forearm.

The adjustable support arm of the present invention has the function of adjusting the force value with a knob, and has multiple modes for adjusting the force value. The user can flexibly choose to turn the knob directly or through a tool. The support arm of this device also has a sound feedback function. When the knob is turned or the rear arm is rotated, the support arm will make a sound to remind the user of the state at this time and give sound feedback to prevent the user from being confused when adjusting. Whether the installation has been completed, it is more convenient to use.

Description of drawings

Fig. 1 is a structural schematic diagram of the adjustable support arm of the present invention.

Fig. 2a is a schematic diagram of the first sound feedback mechanism including steel balls, springs and set screws of the knob adjustment structure of the adjustable support arm of the present invention.

Fig. 2b is a schematic diagram of the first sound feedback mechanism including the second pinball screw of the knob adjustment structure of the adjustable support arm of the present invention.

Fig. 3a is a schematic diagram of a second sound feedback mechanism including steel balls, springs and set screws of the rear arm connection block of the adjustable support arm of the present invention.

Fig. 3b is a schematic diagram of the second sound feedback mechanism including the second pinball screw of the rear arm connection block of the adjustable support arm of the present invention.

Reference signs:

1 forearm

2 rear arms

3 Rear arm connection block

4 first forearm

5 second forearm

6 knobs

7 Adjustment shaft

8 gears

9 Adjusting screw

10 wrench

11 Knob adjustment structure

12 Second marble screw

21 steel ball

22 springs

23 set screw

Detailed ways

In order to describe the technical content of the present invention more clearly, further description will be given below in conjunction with specific embodiments.

The adjustable support arm of the present invention includes a forearm 1, a rear arm 2, a knob adjustment structure 11 and a rear arm connection block 3, the knob adjustment structure 11 is installed at the end of the forearm 1, and adjusted by rotating the knob adjustment structure 11 elastic force, the rear arm connection block 3 is fixed on the forearm 1, and the rear arm connection block 3 is connected to the rear arm 2 by being inserted into the installation hole; the knob adjustment structure 11 has a first sound feedback mechanism, And/or the rear arm connection block 3 has a second sound feedback mechanism, and the first sound feedback mechanism and/or the second sound feedback mechanism emit sound during rotation, providing sound feedback for the user.

As a preferred embodiment of the present invention, the knob adjustment structure 11 includes an adjustment shaft 7, a knob 6, an adjustment screw 9, and a gear 8. There is a notch inside the end of the forearm 1, and the adjustment shaft 7 is embedded in In the notch, the gear 8 is sleeved on the adjustment shaft 7, the adjustment shaft 7 is connected with the adjustment screw 9, the gear 8 and the knob 6, the adjustment shaft 7 drives the gear 8 to rotate, the knob 6 and the adjustment The screw 9 is connected through the adjustment shaft 7 for synchronization. The knob 6 is fastened on the forearm 1, and the knob 6 is rotated to drive the adjustment screw 9 to rotate through the adjustment shaft 7 to adjust the elastic force.

As a preferred embodiment of the present invention, the first sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23, and the set screw 23 fixes the steel ball 21 and the spring 22 in the threaded hole of the forearm 1, and the top In the teeth of the gear 8, during the rotation of the knob 6, the adjustment screw 9 is driven by the adjustment shaft 7 to rotate, and the gear 8 is driven to rotate by the adjustment shaft 7, and rubs against the steel ball 21 to make a sound;

Alternatively, the first sound feedback mechanism includes a second pinball screw 12, the second pinball screw 12 is fixed in the threaded hole of the forearm 1, and is pushed against the teeth of the gear 8, and the knob 6 is rotated Among them, the adjusting screw 9 is driven to rotate by the adjusting shaft 7, and the gear 8 is driven to rotate by the adjusting shaft 7, and rubs against the second pinball screw 12 to make a sound.

As a preferred embodiment of the present invention, the bottom of the rear arm connection block 3 has a gear 8, and the second sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23. When the rear arm connection block 3 When inserting the rear arm 2, the set screw 23 will screw the steel ball 21 and the spring 22 in from the bottom of the rear arm 2, and snap into the gear 8 of the rear arm connection block 3, the rear arm connection block 3 is on the rear arm 2 When rotating in the hole, the steel ball 21 and the spring 22 rub against the gear 8 of the rear arm connection block 3 to make a sound, providing the user with sound feedback;

Alternatively, the second sound feedback mechanism includes a second pinball screw 12, and when the rear arm connecting block 3 is inserted into the rear arm 2, the second pinball screw 12 is screwed in from below the rear arm 2, And snap into the gear 8 of the rear arm connection block 3, when the rear arm connection block 3 rotates in the hole of the rear arm 2, the pinball screw rubs against the gear 8 of the rear arm connection block 3 to make a sound, providing the user with sound feedback.

Specifically, the knob adjustment structure 11 may have a first sound feedback mechanism, which emits sound during rotation to provide sound feedback, and the rear arm connecting block 3 may also have a second sound feedback mechanism, which emits sound during rotation to provide sound feedback, And in the first sound feedback mechanism or the second sound feedback mechanism, can have two kinds of forms, be respectively steel ball 21, spring 22, and set screw 23, or be the second pinball screw 12. Therefore, the device can have the following forms:

Form one:

The knob adjustment structure has a first sound feedback mechanism, and the first sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23, and the set screw 23 fixes the steel ball 21 and the spring 22 in the threaded hole of the forearm 1 , topped in the teeth of the gear 8, during the rotation of the knob 6, the adjustment screw 9 is driven to rotate by the adjustment shaft 7, and the gear 8 is driven by the adjustment shaft 7 to rotate, and rubs against the steel ball 21 to make a sound.

Form two:

The knob adjustment structure has a first sound feedback mechanism, and the first sound feedback mechanism includes a second pinball screw 12 , and the second pinball screw 12 is fixed in the threaded hole of the forearm 1 and pushed against the teeth of the gear 8 , during the rotation of the knob 6, the adjustment screw 9 is driven to rotate by the adjustment shaft 7, and the gear 8 is driven to rotate by the adjustment shaft 7, and rubs against the second pinball screw 12 to make a sound.

Form three:

The rear arm connection block has a second sound feedback mechanism, and the second sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23. There is a gear 8 at the bottom of the rear arm connection block 3. When the rear arm connection block 3 When the arm connecting block 3 is inserted into the rear arm 2, the set screw 23 will screw the steel ball 21 and the spring 22 in from the bottom of the rear arm 2, and snap into the gear 8 of the rear arm connecting block 3, and the rear arm connecting block 3 will When the hole of the rear arm 2 rotates, the steel ball 21 and the spring 22 rub against the gear 8 of the rear arm connection block 3 to make a sound, providing the user with sound feedback.

Form four:

The rear arm connection block has a second sound feedback mechanism, the second sound feedback mechanism includes a second pinball screw 12, and the bottom of the rear arm connection block 3 has a gear 8, when the rear arm connection block 3 When inserting the rear arm 2, the second pinball screw 12 is screwed in from the bottom of the rear arm 2, and snapped into the gear 8 of the rear arm connection block 3, when the rear arm connection block 3 rotates in the hole of the rear arm 2 , the friction between the pinball screw and the gear 8 of the rear arm connection block 3 makes a sound, providing the user with sound feedback.

Form five:

The knob adjustment structure has a first sound feedback mechanism, and the first sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23, and the set screw 23 fixes the steel ball 21 and the spring 22 in the threaded hole of the forearm 1 , topped in the teeth of the gear 8, during the rotation of the knob 6, the adjustment screw 9 is driven to rotate by the adjustment shaft 7, and the gear 8 is driven by the adjustment shaft 7 to rotate, and rubs against the steel ball 21 to make a sound;

The rear arm connection block has a second sound feedback mechanism, and the second sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23. There is a gear 8 at the bottom of the rear arm connection block 3. When the rear arm connection block 3 When the arm connecting block 3 is inserted into the rear arm 2, the set screw 23 will screw the steel ball 21 and the spring 22 in from the bottom of the rear arm 2, and snap into the gear 8 of the rear arm connecting block 3, and the rear arm connecting block 3 will When the hole of the rear arm 2 rotates, the steel ball 21 and the spring 22 rub against the gear 8 of the rear arm connection block 3 to make a sound, providing the user with sound feedback.

Form six:

The knob adjustment structure has a first sound feedback mechanism, and the first sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23, and the set screw 23 fixes the steel ball 21 and the spring 22 in the threaded hole of the forearm 1 , topped in the teeth of the gear 8, during the rotation of the knob 6, the adjustment screw 9 is driven to rotate by the adjustment shaft 7, and the gear 8 is driven by the adjustment shaft 7 to rotate, and rubs against the steel ball 21 to make a sound;

The rear arm connection block has a second sound feedback mechanism, the second sound feedback mechanism includes a second pinball screw 12, and the bottom of the rear arm connection block 3 has a gear 8, when the rear arm connection block 3 When inserting the rear arm 2, the second pinball screw 12 is screwed in from the bottom of the rear arm 2, and snapped into the gear 8 of the rear arm connection block 3, when the rear arm connection block 3 rotates in the hole of the rear arm 2 , the friction between the pinball screw and the gear 8 of the rear arm connection block 3 makes a sound, providing the user with sound feedback.

Form seven:

The knob adjustment structure has a first sound feedback mechanism, and the first sound feedback mechanism includes a second pinball screw 12 , and the second pinball screw 12 is fixed in the threaded hole of the forearm 1 and pushed against the teeth of the gear 8 , during the rotation of the knob 6, the adjustment screw 9 is driven by the adjustment shaft 7 to rotate, and the gear 8 is driven to rotate by the adjustment shaft 7, and rubs against the second pinball screw 12 to make a sound;

The rear arm connection block has a second sound feedback mechanism, and the second sound feedback mechanism includes a steel ball 21, a spring 22 and a set screw 23. There is a gear 8 at the bottom of the rear arm connection block 3. When the rear arm connection block 3 When the arm connecting block 3 is inserted into the rear arm 2, the set screw 23 will screw the steel ball 21 and the spring 22 in from the bottom of the rear arm 2, and snap into the gear 8 of the rear arm connecting block 3, and the rear arm connecting block 3 will When the hole of the rear arm 2 rotates, the steel ball 21 and the spring 22 rub against the gear 8 of the rear arm connection block 3 to make a sound, providing the user with sound feedback.

Form eight:

The knob adjustment structure has a first sound feedback mechanism, and the first sound feedback mechanism includes a second pinball screw 12 , and the second pinball screw 12 is fixed in the threaded hole of the forearm 1 and pushed against the teeth of the gear 8 , during the rotation of the knob 6, the adjustment screw 9 is driven by the adjustment shaft 7 to rotate, and the gear 8 is driven to rotate by the adjustment shaft 7, and rubs against the second pinball screw 12 to make a sound;

The rear arm connection block has a second sound feedback mechanism, the second sound feedback mechanism includes a second pinball screw 12, and the bottom of the rear arm connection block 3 has a gear 8, when the rear arm connection block 3 When inserting the rear arm 2, the second pinball screw 12 is screwed in from the bottom of the rear arm 2, and snapped into the gear 8 of the rear arm connection block 3, when the rear arm connection block 3 rotates in the hole of the rear arm 2 , the friction between the pinball screw and the gear 8 of the rear arm connection block 3 makes a sound, providing the user with sound feedback. As a preferred embodiment of the present invention, the knob adjustment structure 11 also includes a wrench 10, the top of the knob 6 has an adjustment hole, one end of the wrench 10 is inserted into the adjustment hole, and the knob 6 is rotated by turning the wrench 10 .

As a preferred embodiment of the present invention, the adjustment shaft 7 is a hexagonal shaft or a non-rotating shaft.

As a preferred embodiment of the present invention, the forearm 1 includes a first forearm 4 assembly and a second forearm 5 assembly, the structure of the first forearm 4 assembly and the second forearm 5 assembly is similar, and the first forearm 4 assembly is assembled The forearm 1 is composed of the second forearm 5 assembly, and the first sound feedback mechanism is fixed in the threaded hole of the second forearm 5 .

In a specific embodiment of the present invention, it has the function of adjusting the force value of the knob and the function of sound feedback.

(1) The function of the knob to adjust the force value:

The present invention has two modes of adjusting the force value, that is, adjusting the knob 6 directly clockwise or counterclockwise, or adjusting through the adjustment hole at the top of the knob 6 with a tool.

The structural principles are shown in Figures 2a and ab: the adjustment shaft 7 is connected to the adjustment screw 9 and the knob 6 . The knob 6 snaps onto the first forearm assembly 4 and the second forearm assembly 5 . Turn the knob 6 to drive the adjustment screw 9 to rotate through the adjustment shaft 7 to realize the adjustment of the elastic force. The user can also use the wrench 10 to turn the knob 6 to adjust the elastic force. The elastic force refers to the load-bearing force of the forearm, that is, the force value that can reach a balanced state when a display with a certain weight is loaded. When reaching equilibrium, the monitor can achieve "free stop" within an adjustable height range.

As shown in Figure 2a, the adjustment shaft 7, that is, the hexagonal shaft, is connected with the adjustment screw 9, the gear 8 and the knob 6; The spring 22 is fixed to the threaded hole of the second forearm 5 , against the teeth of the gear 8 . Turn the knob 6 to drive the adjustment screw 9 to rotate through the adjustment shaft 7 to realize the adjustment of the elastic force. During the adjustment process, the gear 8 is driven by the adjustment shaft 7 to rotate, and rubs against the steel ball 21 to make a sound, thereby notifying the user that the adjustment of the elastic force is effective. The user can also use the wrench 10 to turn the knob to adjust the elastic force.

(2) Sound feedback function:

A. When adjusting the force value, there will be a rhythmic sound when rotating, giving feedback to the operator:

The structural principle is shown in Figure 2b, the adjustment shaft 7 drives the gear 8 to rotate, the second pinball screw 12 is screwed into the threaded hole of the forearm 1, and is pushed against the teeth of the gear 8, and the second pinball screw 12 rubs against the gear 8 to make a sound .

B. When rotating the product, it emits a rhythmic sound and gives feedback to the operator:

The structural principle is shown in Figure 3b. The bottom of the rear arm connecting block 3 has teeth, and the second pinball screw 12 is screwed in from the bottom of the rear arm 2. When the rear arm connecting block 3 is inserted into the rear arm 2, the second pinball screw 12 is stuck. When the rear arm connection block 3 rotates in the hole of the rear arm 2, the second pinball screw 12 rubs against the teeth of the rear arm connection block 3 to make a sound. As shown in Fig. 3a, the second sound feedback mechanism includes steel balls, springs and set screws, and the structural principle is the same as above.

For the specific implementation solution of this embodiment, reference may be made to relevant descriptions in the foregoing embodiments, and details are not repeated here.

It can be understood that, the same or similar parts in the above embodiments can be referred to each other, and the content that is not described in detail in some embodiments can be referred to the same or similar content in other embodiments.

It should be noted that, in the description of the present invention, the terms "first", "second" and so on are only used for description purposes, and should not be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" means at least two.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The adjustable support arm of the present invention has the function of adjusting the force value with a knob, and has multiple modes for adjusting the force value. The user can flexibly choose to turn the knob directly or through a tool. The support arm of this device also has a sound feedback function. When the knob is turned or the rear arm is rotated, the support arm will make a sound to remind the user of the state at this time and give sound feedback to prevent the user from being confused when adjusting. Whether the installation has been completed, it is more convenient to use.

In this specification, the invention has been described with reference to specific embodiments thereof. However, it is obvious that various modifications and changes can be made without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.

Claims (7)

1. An adjustable support arm, characterized in that, the adjustable support arm comprises a forearm, a rear arm, a knob adjustment structure and a rear arm connection block, and the knob adjustment structure is installed at the end of the forearm, and adjusted by rotating the knob structure to adjust the elastic force, the rear arm connection block is fixed on the forearm, and the rear arm connection block is connected to the rear arm by being inserted into the installation hole; the knob adjustment structure has a first sound feedback mechanism, and/ Or the rear arm connection block has a second sound feedback mechanism, and the first sound feedback mechanism and/or the second sound feedback mechanism emit sound during rotation to provide sound feedback for the user. 2. The adjustable support arm according to claim 1, wherein the knob adjustment structure includes an adjustment shaft, a knob, an adjustment screw and a gear, there is a notch inside the end of the forearm, and the adjustment The shaft is embedded in the notch, the gear is sleeved on the adjustment shaft, the adjustment shaft is connected with the adjustment screw, the gear and the knob, the adjustment shaft drives the gear to rotate, and the knob and the adjustment screw are connected through the adjustment shaft. Synchronously, the knob is fastened on the forearm, and the knob is rotated to drive the adjustment screw to rotate through the adjustment shaft to adjust the elastic force. 3. The adjustable support arm according to claim 2, wherein the first acoustic feedback mechanism comprises a steel ball, a spring and a set screw, and the set screw fixes the steel ball and the spring to the threads of the forearm The hole is placed in the tooth of the gear. During the rotation of the knob, the adjustment screw is driven by the adjustment shaft to rotate, and the gear is driven by the adjustment shaft to rotate and rub against the steel ball to make a sound; Alternatively, the first sound feedback mechanism includes a second pinball screw, the second pinball screw is fixed in the threaded hole of the forearm, and is pushed against the teeth of the gear. During the rotation of the knob, the adjustment shaft The adjusting screw is driven to rotate, and the gear is driven to rotate by the adjusting shaft, and rubs against the second pinball screw to make a sound. 4. The adjustable support arm according to claim 1, wherein there is a gear at the bottom of the connecting block of the rear arm, and the second sound feedback mechanism includes a steel ball, a spring and a set screw, when the When the connecting block of the rear arm is inserted into the rear arm, the set screw will screw the steel ball and spring in from the bottom of the rear arm, and snap into the gear of the connecting block of the rear arm. When the connecting block of the rear arm rotates in the hole of the rear arm , the friction between the steel ball and the spring and the gear of the rear arm connection block makes a sound, providing the user with sound feedback; Alternatively, the second sound feedback mechanism includes a second pinball screw, and when the rear arm connecting block is inserted into the rear arm, the second pinball screw is screwed in from the bottom of the rear arm and snapped into the rear arm In the gear of the connecting block, when the rear arm connecting block rotates in the hole of the rear arm, the friction between the pinball screw and the gear of the rear arm connecting block makes a sound, providing the user with sound feedback. 5. The adjustable support arm according to claim 1, characterized in that, the knob adjustment structure further comprises a wrench, the top of the knob has an adjustment hole, one end of the wrench is inserted into the adjustment hole, and by turning Wrench to turn the knob. 6. The adjustable support arm according to claim 2, wherein the adjustment shaft is a hexagonal shaft or a non-rotating shaft. 7. The adjustable support arm according to claim 1, wherein the forearm comprises a first forearm assembly and a second forearm assembly, the first forearm assembly and the second forearm assembly are similar in structure and are assembled together The first forearm assembly and the second forearm assembly form the forearm, and the first sound feedback mechanism is fixed in the threaded hole of the second forearm.

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