A transfer device for coal mine electromechanical equipment

Abstract

The application discloses a coal mine electromechanical equipment transfer device and relates to the technical field of electromechanical equipment. The device comprises a base provided with a plurality of rollers at the bottom, a first protective frame is arranged on the top surface of the base, a second protective frame is slidably arranged outside the first protective frame, the second protective frame is connected with a lifting power assembly, the lifting power assembly drives the second protective frame to lift along the height direction relative to the first protective frame, the first protective frame and the second protective frame are both provided with loading and unloading openings for loading and unloading electromechanical equipment, movable loading and unloading plates are arranged at the loading and unloading openings, locking assemblies are arranged between the loading and unloading plates and the first protective frame or the base, and the locking assemblies are used for fixing the positions of the loading and unloading plates. Under the drive of the lifting power assembly, the second protective frame can lift along the height direction relative to the first protective frame, the lateral height of the transfer device can be adjusted, the lateral protection requirements of electromechanical equipment of different heights are met, and the problem that the electromechanical equipment is scratched on the side during transfer is avoided.

Description

Technical Field

[0001] This invention relates to the field of electromechanical equipment technology, and more specifically, to a transfer device for coal mine electromechanical equipment. Background Technology

[0002] The mining and production processes in underground coal mines require the operation of a large number of coal mine electromechanical equipment. This equipment is large and heavy, necessitating transportation via trolleys or other transfer devices.

[0003] Existing protective devices for moving electromechanical equipment use fixing mechanisms to secure the equipment to be transported within the transport device to prevent collisions and damage during transportation. However, the height of the transport device is fixed, and when taller electromechanical equipment is placed on it, the top of the equipment cannot be shielded, making it prone to side scraping during loading, unloading, and transportation.

[0004] In conclusion, how to avoid side-scratching of electromechanical equipment during transportation is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a transfer device for coal mine electromechanical equipment that can meet the lateral protection requirements of electromechanical equipment at different heights, thereby avoiding side scraping problems during transfer.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A transfer device for coal mine electromechanical equipment includes a base with a plurality of rollers at the bottom, a first protective frame on the top surface of the base, a second protective frame slidably disposed outside the first protective frame, the second protective frame being connected to a lifting power component, the lifting power component driving the second protective frame to move up and down relative to the first protective frame in the height direction;

[0008] Both the first protective frame and the second protective frame are provided with loading and unloading ports for loading and unloading electromechanical equipment. A movable loading and unloading plate is provided at the loading and unloading port, and a locking component is provided between the loading and unloading plate and the base or the first protective frame. The locking component is used to fix the position of the loading and unloading plate.

[0009] Preferably, one of the first protective frame and the second protective frame is provided with a slide groove arranged along the height direction, and the other is provided with a slider slidably installed in the slide groove. The slider is provided with a limiting part at the end that is relatively away from the slide groove, and the limiting part is used to prevent the slider from coming out of the slide groove along the normal direction.

[0010] Preferably, the lifting power assembly includes a vertically arranged lifting motor, which is connected to the base via a motor bracket and to the second protective frame.

[0011] Preferably, the lifting power assembly includes a horizontally arranged adjusting screw, an adjusting sleeve is slidably sleeved on the adjusting screw, the adjusting sleeve is connected to a vertically arranged connecting rod, and the connecting rod is slidably disposed in a horizontal groove of the base;

[0012] The connecting rod has a wedge-shaped transmission block at its top, which is relatively far from the adjusting screw. The transmission block is used to contact and abut against the wedge-shaped force-bearing block on the outer surface of the second protective frame. When the adjusting screw rotates, the adjusting screw sleeve drives the transmission block to move laterally, so as to push the force-bearing block and the second protective frame to rise in the height direction.

[0013] Preferably, the outer side of the second protective frame is provided with two force-bearing blocks, and the force-bearing blocks are symmetrically arranged with respect to the vertical symmetrical surface of the second protective frame;

[0014] The adjusting screw includes a connecting part and screw parts located at both ends of the connecting part, and two adjusting screw sleeves are respectively fitted over the two screw parts.

[0015] Preferably, at least one end of the adjusting screw is provided with an adjusting part, and the diameter of the adjusting part is larger than the diameter of the screw part.

[0016] Preferably, the loading and unloading plate is hinged to the base, and when the loading and unloading plate is in the loading and unloading position, the end of the loading and unloading plate that is relatively away from the base is in contact with the ground.

[0017] Preferably, the locking assembly includes a limiting adjustment screw and a guide rod disposed at the top of the first protective frame, the limiting adjustment screw is externally threaded with a limiting plate, and the guide rod is slidably sleeved in the guide hole of the limiting plate;

[0018] One of the bottom of the limiting plate and the top of the loading and unloading plate is provided with a limiting protrusion, and the other is provided with a limiting groove that engages with the limiting protrusion.

[0019] Preferably, the top of the guide rod is provided with a limiting part, and the diameter of the limiting part is larger than the diameter of the guide rod.

[0020] Preferably, the locking assembly is symmetrically arranged about the vertical symmetrical surface of the first protective frame.

[0021] The coal mine electromechanical equipment transfer device provided by the present invention has a second protective frame that can be raised and lowered relative to the first protective frame in the height direction under the drive of the lifting power component, thereby adjusting the lateral height of the transfer device and meeting the lateral protection requirements of electromechanical equipment of different heights, thus avoiding the problem of side scraping of electromechanical equipment during transfer. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 A schematic diagram of a specific embodiment of the transfer device for coal mine electromechanical equipment provided by the present invention;

[0024] Figure 2 A schematic diagram of the transfer device for coal mine electromechanical equipment from another angle;

[0025] Figure 3 This is an assembly diagram of the first and second protective frames;

[0026] Figure 4 This is an assembly diagram of the base and mounting plate.

[0027] Figures 1-4 middle:

[0028] 1-Base; 11-Roller; 12-Horizontal slide rail; 13-Handrail; 14-Loading / unloading plate mounting slot; 15-Screw mounting seat; 2-First protective frame; 21-Slider; 3-Second protective frame; 31-Vertical slide rail; 4-Loading / unloading plate; 41-Limiting insertion hole; 51-Adjusting screw; 52-Adjusting screw sleeve; 53-Connecting rod; 531-Transmission block; 54-Force-bearing block; 61-Limiting adjusting screw; 62-Guide rod; 63-Limiting plate; 631-Limiting rod. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The core of this invention is to provide a transfer device for coal mine electromechanical equipment. The lateral height of the transfer device is adjustable, which meets the lateral protection requirements of electromechanical equipment of different heights, thereby avoiding the problem of side scraping of electromechanical equipment during transfer.

[0031] The transfer device for coal mine electromechanical equipment provided by the present invention includes a base 1 with a plurality of rollers 11 at the bottom, a first protective frame 2 on the top surface of the base 1, a second protective frame 3 slidably disposed outside the first protective frame 2, the second protective frame 3 being connected to a lifting power component, and the lifting power component driving the second protective frame 3 to move up and down relative to the first protective frame 2 in the height direction.

[0032] Both the first protective frame 2 and the second protective frame 3 are provided with loading and unloading ports for loading and unloading electromechanical equipment. A movable loading and unloading plate 4 is provided at the loading and unloading port, and a locking component is provided between the loading and unloading plate 4 and the base 1 or the first protective frame 2. The locking component is used to fix the position of the loading and unloading plate 4.

[0033] Please refer to Figure 1 The first protective frame 2 and the second protective frame 3 are slidably connected. The overall lateral height of the protective frame of the transfer device can be adjusted by raising and lowering the second protective frame 3 relative to the first protective frame 2 in the height direction, thereby meeting the lateral protection requirements of electromechanical equipment of different heights and successfully preventing the top of the electromechanical equipment from being higher than the top surface of the second protective frame 3.

[0034] The heights of the first protective frame 2 and the second protective frame 3 are determined according to the height range of the electromechanical equipment in actual production. Preferably, the height of the first protective frame 2 is the same as the minimum height h of the electromechanical equipment, and the stroke of the second protective frame 3 is greater than or equal to the height difference Δh of the electromechanical equipment, so that when the second protective frame 3 is at its maximum stroke, the height of the top surface of the second protective frame 3 is greater than or equal to the maximum height H of the electromechanical equipment; wherein, the height difference Δh of the electromechanical equipment is Hh.

[0035] The first protective frame 2 and the second protective frame 3 are slidably connected. Specifically, the two can be slidably connected through a guide rail slider pair, a ball screw pair, etc. Considering the structural complexity and maintainability of the protective device, one of the first protective frame 2 and the second protective frame 3 is usually provided with a slide groove set along the height direction, and the other is provided with a slider 21 slidably installed in the slide groove. The end of the slider 21 that is relatively far away from the slide groove is provided with a limiting part, which is used to prevent the slider from coming out of the slide groove along the normal direction.

[0036] Please refer to Figure 1 The second protective frame 3 is provided with a vertical slide groove 31 along the height direction, and a slider 21 protrudes from the outer surface of the first protective frame 2. The slider 21 is slidably installed in the vertical slide groove 31; one end of the slider 21 is provided with a limiting part, which can be a circular limiting part, such as... Figure 3The rectangular limiting part shown can be used as long as the diameter of the limiting part is greater than the outer diameter of the slider 21. The other end of the slider 21 is connected to the first protective frame 2. The slider 21 and the first protective frame 2 can be connected by a detachable method such as threaded connection or pin connection.

[0037] The lifting power component is connected to the second protective frame 3 and is used to drive the second protective frame 3 to move up and down relative to the first protective frame 2 in the height direction. The lifting power component can be set as a linear power mechanism such as a linear motor, cylinder, or hydraulic cylinder, or as a transmission component such as a servo motor, ball screw pair, or gear rack pair. Of course, considering that the second protective frame 3 is relatively light, it can also be without a power source and only the transmission component is used to drive the second protective frame 3 to move up and down.

[0038] In order to enable the mechanical and electrical equipment to be loaded and unloaded into or out of the transfer device in a normal manner, both the first protective frame 2 and the second protective frame 3 are provided with loading and unloading ports. The loading and unloading ports of the first protective frame 2 are located at the same positions as those of the second protective frame 3, so as to reduce the transfer path of the mechanical and electrical equipment and facilitate the rapid loading and unloading needs of the mechanical and electrical equipment.

[0039] The loading and unloading port can be located on the side or at the rear of the transfer device. However, if the loading and unloading port is located on the side, the side of the first protective frame 2 or the side of the second protective frame 3 with the loading and unloading port would be divided into two parts. Each part would require a lifting power component to drive synchronous lifting, which would not only result in a complex structure and high equipment cost, but also make the lifting control more complex and less reliable as both parts would need to be controlled synchronously. Therefore, preferably, the loading and unloading port can be located at the rear of both the first protective frame 2 and the second protective frame 3.

[0040] In order to protect the surface of the electromechanical equipment that is relatively close to the loading and unloading port, the loading and unloading port is equipped with a movable loading and unloading plate 4. Considering that the second protective frame 3 can be raised and lowered relative to the base 1 and the first protective frame 2 in the height direction, the loading and unloading plate 4 is connected to the base 1 or the first protective frame 2. Specifically, the two can be connected by hinged pivot or by sliding pair such as guide rail slider mechanism.

[0041] In order to facilitate fixing the position of the loading and unloading plate 4 during transfer and to prevent the mechanical and electrical equipment from colliding or even falling out, a locking component is provided between the loading and unloading plate 4 and the base 1 or the first protective frame 2. The locking component is used to fix the position of the loading and unloading plate 4 so that the loading and unloading plate 4 is fixed in the loading and unloading position or the transfer position. When the loading and unloading plate 4 is in the loading and unloading position, the loading and unloading plate 4 is exposed at the loading and unloading port. When the loading and unloading plate 4 is in the transfer position, the loading and unloading plate 4 is set perpendicular to the base 1.

[0042] The locking components can be specifically set as locking screws, fixing pins, fixing buckles, etc. The number and distribution of the locking components need to be determined according to the size and installation method of the loading and unloading plate 4 in actual production. The locking components are symmetrically arranged about the vertical symmetrical surface of the first protective frame 2 so that the locking force on the left and right ends of the loading and unloading plate 4 is relatively uniform, and the loading and unloading plate 4 is prevented from opening on one side during the transfer process.

[0043] In this embodiment, the second protective frame 3 can be raised and lowered relative to the first protective frame 2 in the height direction under the drive of the lifting power component, thereby adjusting the lateral height of the transfer device and meeting the lateral protection requirements of electromechanical equipment of different heights, thus avoiding the problem of side scratches of electromechanical equipment during transfer.

[0044] Preferably, in order to facilitate the movement of the transfer device, the outer surface of the base 1 is provided with a handrail 13. The handrail 13 is used for the user to push the base 1 so as to better control the forward movement and turning of the transfer device. The specific material, structure, size, setting position and connection method of the handrail 13 are determined according to the needs of actual production and with reference to the existing handrail structure, and will not be described in detail here.

[0045] Based on the above embodiments, the structure of the lifting power assembly is defined. The lifting power assembly includes a horizontally arranged adjusting screw 51, an adjusting screw sleeve 52 is slidably sleeved on the outside of the adjusting screw 51, the adjusting screw sleeve 52 is connected to a vertically arranged connecting rod 53, and the connecting rod 53 is slidably arranged in the horizontal sliding groove 12 of the base 1.

[0046] The connecting rod 53 has a wedge-shaped transmission block 531 at its top, which is relatively far from the adjusting screw 51. The transmission block 531 is used to contact and abut against the wedge-shaped force-bearing block 54 on the outer surface of the second protective frame 3. When the adjusting screw 51 rotates, the adjusting screw sleeve 52 drives the transmission block 531 to move laterally, so as to push the force-bearing block 54 and the second protective frame 3 to rise in the height direction.

[0047] The adjusting screw 51 is mounted on the side of the base 1 via the screw mounting seat 15, as shown below. Figure 1 and Figure 2 As shown, at least one end of the adjusting screw 51 protrudes beyond the screw mounting base 15 in the length direction to adjust the rotation of the adjusting screw 51;

[0048] An adjusting screw sleeve 52 is provided on the outer sleeve of the adjusting screw 51. The adjusting screw sleeve 52 is connected to a vertically arranged connecting rod 53. The connecting rod 53 is slidably disposed in the transverse sliding groove 12 of the base 1. The sliding connection between the connecting rod 53 and the transverse sliding groove 12 restricts the movement direction of the adjusting screw sleeve 52, thereby converting the rotation of the adjusting screw 51 into the axial reciprocating movement of the adjusting screw sleeve 52 along the adjusting screw 51.

[0049] The top of the connecting rod 53 is provided with a wedge-shaped transmission block 531. The transmission block 531 contacts and abuts against the force-bearing block 54 of the second protective frame 3. The wedge-shaped contact surface can move the transmission block 531 axially back and forth, which is converted into the force-bearing block 54 moving up and down in the vertical direction.

[0050] In this embodiment, the adjusting screw 51 drives the adjusting sleeve 52 and the connecting rod 53 to move axially, and then drives the force block 54 to rise and fall vertically through the wedge-shaped contact surface of the transmission block 531 and the force block 54. The lifting power component has a relatively simple structure, strong structural stability and reliability, and high adjustment accuracy.

[0051] Based on the above embodiments, two force-bearing blocks 54 can be provided on the outer side of the second protective frame 3, and the force-bearing blocks 54 are symmetrically arranged about the vertical symmetrical surface of the second protective frame 3.

[0052] The adjusting screw 51 includes a connecting part and screw parts located at both ends of the connecting part, and two adjusting screw sleeves 52 are respectively fitted onto the two screw parts.

[0053] Compared to the second protective frame 3 which only has a single force-bearing block 54 on its outer side, the symmetrical design of the two force-bearing blocks 54 makes the force on the second protective frame 3 more uniform, allowing the second protective frame 3 to rise and fall more smoothly relative to the first protective frame 2 in the height direction.

[0054] Preferably, at least one end of the adjusting screw 51 is provided with an adjusting part, the diameter of which is larger than the diameter of the screw part; the adjusting part is used to limit the axial movement of the adjusting screw 51, so as to avoid the adjusting screw 51 moving axially and affecting the cooperation state of the transmission block 531 and the force block 54.

[0055] Alternatively, a lifting power assembly can be installed, including a vertically positioned lifting motor. The lifting motor is connected to the base 1 via a motor bracket and to the second protective frame 3. The lifting motor is a linear motor, and the extension and retraction of the motor shaft drives the second protective frame 3 to move up and down relative to the first protective frame 2 in the height direction. The structure is simple, the lifting adjustment and control are simple, and the adjustment accuracy is high.

[0056] Based on the above embodiments, the connection method of the loading and unloading plate 4 is defined. The loading and unloading plate 4 is hinged to the base 1. When the loading and unloading plate 4 is in the loading and unloading position, the end of the loading and unloading plate 4 that is relatively far away from the base 1 abuts against the ground.

[0057] Please refer to Figure 4 The loading / unloading plate 4 is hinged to the loading / unloading plate mounting groove 14 of the base 1 via a pivot. When the loading / unloading plate 4 is in the transfer position, such as Figure 1 As shown, the bottom surface of the loading and unloading plate 4 is a certain distance from the bottom of the loading and unloading plate mounting groove 14 so that the loading and unloading plate 4 can rotate around the axis.

[0058] In this embodiment, the loading and unloading plate 4 can be used as a ramp at the loading and unloading position, which facilitates the transfer of electromechanical equipment between the ground and the base 1.

[0059] Based on the above embodiments, the structure of the locking assembly is defined. The locking assembly includes a limit adjusting screw 61 and a guide rod 62 located at the top of the first protective frame 2. The limit adjusting screw 61 is externally threaded with a limit plate 63, and the guide rod 62 is slidably sleeved in the guide hole of the limit plate 63.

[0060] One of the bottom of the limiting plate 63 and the top of the loading and unloading plate 4 is provided with a limiting protrusion, and the other is provided with a limiting groove that engages with the limiting protrusion.

[0061] The guide rod 62 is slidably sleeved in the guide hole of the limiting plate 63. The guide rod 62 is used to limit the rotation of the limiting plate 63 so that the rotation of the limiting adjusting screw 61 can be converted into the movement of the limiting plate 63 along the axial direction of the limiting adjusting screw 61 by utilizing the threaded pair between the limiting adjusting screw 61 and the limiting plate 63.

[0062] Preferably, in order to prevent the limiting plate 63 from detaching from the guide rod 62, the top of the guide rod 62 is provided with a limiting part, the diameter of which is larger than the diameter of the guide rod 62. The limiting part can be specifically configured as a limiting plate, a limiting block, etc. The limiting part can not only prevent the limiting plate 63 from detaching from the guide rod 62 and the guide rod 62 from losing its rotation restriction function on the limiting plate 63, but also limit the lifting stroke of the limiting plate 63.

[0063] The bottom of the limiting plate 63 and the top of the loading and unloading plate 4 are connected by a limiting protrusion and a limiting groove, so that the loading and unloading plate 4 can be fixed in the loading and unloading position by using the limiting plate 63; the specific shape of the limiting protrusion and the limiting groove is not limited, as long as they can be stably connected and matched.

[0064] Please refer to Figure 2 and Figure 4 The top of the loading and unloading plate 4 is provided with a limiting hole 41, and the bottom of the limiting plate 63 is provided with a limiting rod 631 for inserting or pulling out of the limiting hole 41.

[0065] In this embodiment, the locking assembly has a simple structure, is easy to adjust, and has a good locking effect.

[0066] It should be noted that the first and second protective frames 2 and 3 in this application are only used to distinguish the different positions and do not contain any limitation on the order.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0068] The foregoing has provided a detailed description of the transfer device for coal mine electromechanical equipment provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A transfer device for coal mine electromechanical equipment, characterized in that, The base (1) includes a base with several rollers (11) at the bottom. The top surface of the base (1) is provided with a first protective frame (2). A second protective frame (3) is slidably provided outside the first protective frame (2). The second protective frame (3) is connected to a lifting power component. The lifting power component drives the second protective frame (3) to rise and fall relative to the first protective frame (2) in the height direction. Both the first protective frame (2) and the second protective frame (3) are provided with loading and unloading ports for loading and unloading of electromechanical equipment. A movable loading and unloading plate (4) is provided at the loading and unloading port, and a locking component is provided between the loading and unloading plate (4) and the base (1) or the first protective frame (2). The locking component is used to fix the position of the loading and unloading plate (4).

2. The transfer device for coal mine electromechanical equipment according to claim 1, characterized in that, One of the first protective frame (2) and the second protective frame (3) is provided with a slide groove arranged along the height direction, and the other is provided with a slider (21) slidably installed in the slide groove. The slider (21) is provided with a limiting part at the end that is relatively away from the slide groove. The limiting part is used to prevent the slider (21) from coming out of the slide groove along the normal direction.

3. The transfer device for coal mine electromechanical equipment according to claim 2, characterized in that, The lifting power assembly includes a vertically arranged lifting motor, which is connected to the base (1) via a motor bracket and is connected to the second protective frame (3).

4. The transfer device for coal mine electromechanical equipment according to claim 2, characterized in that, The lifting power assembly includes a horizontally arranged adjusting screw (51), an adjusting screw sleeve (52) is slidably sleeved on the outside of the adjusting screw (51), the adjusting screw sleeve (52) is connected to a vertically arranged connecting rod (53), and the connecting rod (53) is slidably arranged in the horizontal sliding groove (12) of the base (1); The connecting rod (53) has a wedge-shaped transmission block (531) at its top, which is relatively far from the adjusting screw (51). The transmission block (531) is used to contact and abut against the wedge-shaped force block (54) on the outer surface of the second protective frame (3). When the adjusting screw (51) rotates, the adjusting sleeve (52) drives the transmission block (531) to move laterally, so as to push the force block (54) and the second protective frame (3) to rise in the height direction.

5. The transfer device for coal mine electromechanical equipment according to claim 4, characterized in that, The outer side of the second protective frame (3) is provided with two force-bearing blocks (54), and the force-bearing blocks (54) are symmetrically arranged about the vertical symmetrical surface of the second protective frame (3); The adjusting screw (51) includes a connecting part and a screw part located at both ends of the connecting part, and the two adjusting screw sleeves (52) are respectively sleeved on the two screw parts.

6. The transfer device for coal mine electromechanical equipment according to claim 5, characterized in that, At least one end of the adjusting screw (51) is provided with an adjusting part, the diameter of which is larger than the diameter of the screw part.

7. The transfer device for coal mine electromechanical equipment according to any one of claims 1-6, characterized in that, The loading and unloading plate (4) is hinged to the base (1). When the loading and unloading plate (4) is in the loading and unloading position, the end of the loading and unloading plate (4) that is relatively far away from the base (1) is in contact with the ground.

8. The transfer device for coal mine electromechanical equipment according to claim 7, characterized in that, The locking assembly includes a limiting adjustment screw (61) and a guide rod (62) located at the top of the first protective frame (2). The limiting adjustment screw (61) is externally threaded with a limiting plate (63), and the guide rod (62) is slidably sleeved in the guide hole of the limiting plate (63). One of the bottom of the limiting plate (63) and the top of the loading and unloading plate (4) is provided with a limiting protrusion, and the other is provided with a limiting groove that engages with the limiting protrusion.

9. The transfer device for coal mine electromechanical equipment according to claim 8, characterized in that, The top of the guide rod (62) is provided with a limiting part, the diameter of which is larger than the diameter of the guide rod (62).

10. The transfer device for coal mine electromechanical equipment according to any one of claims 1-6, characterized in that, The locking assembly is arranged symmetrically with respect to the vertical symmetry of the first protective frame (2).

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