Adjustable electric locomotive pantograph pressure detector

Abstract

The utility model relates to the technical field of internal combustion engine locomotive pantograph, disclose adjustable electric locomotive pantograph pressure detector, including host computer, the bottom of host computer is provided with mounting mechanism, the outer wall of host computer is provided with buffer mechanism, buffer mechanism is used for buffering the impact of the impact force that collision occurs, the top left side of host computer is provided with slide hole, the mounting mechanism includes mounting shaft, the top end rotation connection of mounting shaft is in the inner wall bottom of host computer, the bottom fixed connection of mounting shaft has the sliding plate, the inner wall bottom sliding connection of sliding plate has the lead screw, the bottom front and back side of mounting shaft all are fixedly connected with slide block no.

Description

Technical Field

[0001] This utility model relates to the field of pantograph technology for internal combustion locomotives, and in particular to an adjustable pantograph pressure detector for electric locomotives. Background Technology

[0002] The pantograph pressure detector for electric locomotives is a key testing device in the electric locomotive operation and maintenance system. Its core function is to monitor and dynamically adjust the contact pressure between the pantograph and the overhead contact line in real time, ensuring that the pressure is maintained within a safe range suitable for different operating scenarios. This device is widely used in railway locomotive depots, vehicle maintenance bases, and rail transit operation and maintenance stations. It can not only accurately collect core parameters such as static pressure, pressure difference, pantograph lifting height, and pantograph lifting and lowering time, but also avoid two key problems through pressure regulation: first, excessive pressure leads to accelerated wear of the overhead contact line wire and shortens the life of the pantograph slide plate; second, insufficient pressure causes offline arcing, resulting in interruption of current transmission. Especially when hybrid locomotives switch to electric drive, offline problems can lead to unstable power output. Its performance is directly related to the operational safety, power supply reliability, and service life of core components of electric locomotives, making it an important supporting device for intelligent operation and maintenance of modern railway transportation.

[0003] Early pantograph pressure detection devices typically consisted of a separate mechanical force gauge, a manual adjusting screw, and a pointer-type instrument. These required bolts to rigidly connect the force gauge to the pantograph head, and pressure adjustment relied on manual calibration by turning the screw one turn at a time. For hybrid locomotives, where the pantograph installation space is more compact due to the internal combustion engine and transmission system layout, this device suffered from low measurement accuracy and low adjustment efficiency. Furthermore, the bolt fixing required specific mounting holes for different locomotive models, necessitating complete disassembly and reassembly when switching between hybrid and pure electric locomotives, making operation extremely inconvenient. To address these shortcomings, current detection instruments employ an integrated design, combining the pressure sensor, data acquisition module, and electromagnetic adjustment unit into a compact main unit. Data is displayed in real-time on a digital screen, and a pneumatic drive mechanism replaces the manual screw, significantly improving pressure adjustment response speed, especially in hybrid locomotives. Under electric drive conditions, pressure compensation algorithms can avoid interference from internal combustion engine vibration on measurement accuracy. However, the existing installation structure of the detector still has shortcomings in adaptability. Its sensor bracket adopts a design of metal buckles with fixed curvature or connecting plates with preset hole positions, which cannot adapt to the differences in the curvature of the pantograph head and the changes in the spacing of the mounting holes of different models of electric locomotives. When operators switch between hybrid locomotives and pure electric locomotives for testing, they need to carry bracket accessories of different specifications, disassemble the old bracket and install the new bracket. During this process, leveling with shims and securing with straps are also required to ensure the fit of the sensor. When operating on the roof of a hybrid locomotive, the installation time is long for each installation. This not only fails to meet the needs of efficient turnover in railway operation and maintenance, but also increases the safety risk of operators touching the high-temperature components of the internal combustion engine due to the extended high-altitude operation time, highlighting the technical limitations of the existing installation structure in terms of adaptability and convenience. Utility Model Content

[0004] To overcome the above shortcomings, this utility model provides an adjustable pantograph pressure detector for electric locomotives, aiming to improve the problem that the existing technology cannot adaptively adjust the installation structure, resulting in a cumbersome and time-consuming installation process.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an adjustable pantograph pressure detector for electric locomotives, including a main unit, a mounting mechanism at the bottom of the main unit, a buffer mechanism on the outer wall of the main unit for buffering the impact force of a collision, and a sliding hole on the top left side of the main unit.

[0006] The installation mechanism includes an installation shaft, the top end of which is rotatably connected to the bottom of the inner wall of the main unit. A sliding plate is fixedly connected to the bottom end of the installation shaft. A lead screw is slidably connected to the bottom of the inner wall of the sliding plate. A slider is fixedly connected to both the front and rear sides of the bottom of the installation shaft. A slide rail is slidably connected to the inner wall of each slider. A fixing plate is fixedly connected to the left and right ends of each slide rail. A hook is fixedly connected to the front and rear sides of each fixing plate. A stabilizing plate is rotatably connected to the side of each fixing plate that is far apart from the other side. A limit component is provided on the inner wall of the lead screw.

[0007] As a further description of the above technical solution:

[0008] The buffer mechanism includes two fixing bars, the bottoms of which are fixedly connected to the front and rear sides of the top of the main unit, respectively. The bottoms of the two fixing bars are threaded to the same protective shell. A telescopic rod is provided in the middle of the inner wall of the protective shell, and springs are provided on both the left and right sides of the inner wall of the protective shell.

[0009] As a further description of the above technical solution:

[0010] The limiting assembly includes a limiting rod, the outer wall of which is fixedly connected to the inner wall of the lead screw, a limiting block is fixedly connected to the bottom of the mounting shaft, and a guide plate is slidably connected to the bottom of the limiting block.

[0011] As a further description of the above technical solution:

[0012] Stabilizing plates 2 are fixedly connected to the bottom front and rear sides of the main unit, and the bottom of the two stabilizing plates 2 is provided with sliding grooves.

[0013] As a further description of the above technical solution:

[0014] The inner wall of the chute is slidably connected to a second slider, and the bottom of the second slider is fixedly connected to a handle.

[0015] As a further description of the above technical solution:

[0016] A measuring hook is slidably connected to the inner wall of the sliding hole, and an alarm is provided on the rear left side of the main unit.

[0017] As a further description of the above technical solution:

[0018] Multiple heat sinks are fixedly connected to both the left and right sides of the host, and a screen is fixedly connected to the top right side of the host.

[0019] As a further description of the above technical solution:

[0020] A toolbox is fixedly connected to the rear right end of the host, and a connection port is provided on the front left end of the host.

[0021] This utility model has the following beneficial effects:

[0022] 1. In this utility model, the mounting shaft is fixedly connected to the sliding plate, and the sliding plate is slidably engaged with the lead screw. Combined with the slider one sliding along the slide rail, the fixing plate can be adjusted horizontally with the slide rail. With the hook on the fixing plate and the rotatable stabilizing plate one, it can adapt to the differences in pantograph head width and mounting hole position of different vehicle models. There is no need to replace the adapter parts. The limiting component locks the position of the lead screw to ensure no displacement after installation.

[0023] 2. In this utility model, the fixing strip securely connects the protective shell to the top of the main unit. The springs on the left and right sides of the inner wall of the protective shell and the telescopic rod in the middle form a double buffer structure. When the equipment is hit or falls from a height, the spring first absorbs part of the impact energy through elastic deformation, and the telescopic rod extends and retracts synchronously to further offset the impact. The two work together to greatly reduce the impact force on the main unit, avoid damage to the internal components of the main unit due to the collision, and significantly improve the equipment's anti-drop and anti-collision capabilities. Attached Figure Description

[0024] Figure 1 This is a perspective view of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0025] Figure 2 This is a front view of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0026] Figure 3 This is a rear view of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0027] Figure 4 This is a schematic diagram of the installation mechanism of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0028] Figure 5 This is a structural exploded view of the limiting component of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0029] Figure 6 This is a structural exploded view of the buffer mechanism of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0030] Figure 7 This is a structural exploded view of the buffer mechanism of the adjustable pantograph pressure detector for electric locomotives proposed in this utility model.

[0031] Legend:

[0032] 1. Main unit; 2. Mounting mechanism; 201. Mounting shaft; 202. Slide plate; 203. Lead screw; 204. Slider one; 205. Slide rail; 206. Fixing plate; 207. Hook; 208. Stabilizing plate one; 209. Limiting assembly; 2091. Limiting rod; 2092. Limiting block; 2093. Guide plate; 3. Buffering mechanism; 301. Fixing strip; 302. Protective shell; 303. Spring; 304. Telescopic rod; 4. Sliding hole; 5. Stabilizing plate two; 6. Slide groove; 7. Slider two; 8. Handle; 9. Measuring hook; 10. Alarm; 11. Radiator; 12. Screen; 13. Toolbox; 14. Connection port. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] Reference Figure 1 , Figure 2 and Figure 4 An embodiment of this utility model provides an adjustable pantograph pressure detector for electric locomotives, including a main unit 1. The main unit 1 provides an installation carrier and protective shell for various mechanisms and components. An installation mechanism 2 is provided at the bottom of the main unit 1. The installation mechanism 2 is used to achieve precise connection and fixation between the main unit 1 and the pantograph. A buffer mechanism 3 is provided on the outer wall of the main unit 1. The buffer mechanism 3 is used to buffer the impact force of collisions and prevent damage to the main unit 1 and internal components due to collisions. A sliding hole 4 is provided on the top left side of the main unit 1. The sliding hole 4 provides a guide channel for the sliding of subsequent measuring components.

[0035] The mounting mechanism 2 includes a mounting shaft 201, which drives the sliding plate 202 to achieve rotation and lifting adjustment. The top end of the mounting shaft 201 is rotatably connected to the bottom of the inner wall of the main unit 1. This connection allows the mounting shaft 201 to rotate flexibly around the bottom of the inner wall of the main unit 1. The bottom end of the mounting shaft 201 is fixedly connected to the sliding plate 202, which carries the lead screw 203 and drives it to achieve horizontal sliding. The lead screw 203 is slidably connected to the bottom of the inner wall of the sliding plate 202. The lead screw 203 is used to drive the sliding plate 202 and related components to achieve fine horizontal adjustment. Slider 1 204 is fixedly connected to the front and rear sides of the bottom of the mounting shaft 201. Slider 1 204 slides along the slide rail 205 to achieve smooth lifting and lowering of the mounting shaft 201. The inner walls of the two slider 1 204 are slidably connected to the slide rail 205, which provides guidance for the sliding of the slider 1 204 and ensures the stability of the lifting and lowering process of the mounting shaft 201. The left and right ends of the two slide rails 205 are fixedly connected to the fixing plates 20. 6. The fixing plate 206 is used to install the hook 207 and the first stabilizing plate 208, and at the same time realizes the contact and fixation with the pantograph. The front and rear sides of the two fixing plates 206 are fixedly connected with hooks 207. The hooks 207 are used to hook the pantograph mounting holes to realize the quick connection between the fixing plate 206 and the pantograph. The side of the two fixing plates 206 that is far apart is rotatably connected with the first stabilizing plate 208. The first stabilizing plate 208 can be rotated to adjust the angle, increase the contact area with the pantograph or the mounting surface, and improve the installation stability. The inner wall of the lead screw 203 is provided with a limit component 209. The limit component 209 is used to lock the position of the lead screw 203 to prevent the lead screw 203 from shifting after installation and causing the equipment connection to loosen. The rear right end of the main unit 1 is fixedly connected with a toolbox 13. The toolbox 13 is used to store the tools and spare parts required for testing, which are convenient for operators to access. The front left end of the main unit 1 is provided with a connection port 14. The connection port 14 is used to realize the data transmission or power connection between the main unit 1 and external equipment.

[0036] Specifically, in the adjustable pantograph pressure detector for electric locomotives, the main unit 1 provides an installation carrier and protective shell for various mechanisms and components. The installation mechanism 2 achieves precise connection and fixation between the main unit 1 and the pantograph. The buffer mechanism 3 buffers the impact force caused by collisions, preventing damage to the main unit 1 and its internal components. The sliding hole 4 provides a guide channel for the sliding of subsequent measuring components. The mounting shaft 201 drives the sliding plate 202 to achieve rotation and lifting adjustment. The connection between the mounting shaft 201 and the main unit 1 allows the mounting shaft 201 to rotate flexibly. The sliding plate 202 carries the lead screw 203 and drives it to achieve horizontal sliding. The lead screw 203 drives the sliding plate 202 and related components to achieve fine adjustment in the horizontal direction. The slider 204 slides along the slide rail 205. The mounting shaft 201 is raised and lowered smoothly. The slide rail 205 provides guidance for the sliding of the slider 204 to ensure the stability of the mounting shaft 201. The mounting hook 207 on the fixing plate 206 and the stabilizing plate 208 make contact with the pantograph and fix it. The hook 207 hooks the pantograph mounting hole to realize the quick connection between the fixing plate 206 and the pantograph. The stabilizing plate 208 increases the contact area by rotating to adjust the angle and improve the installation stability. The limit component 209 locks the position of the lead screw 203 to prevent the lead screw 203 from shifting after installation and causing the equipment connection to loosen. The toolbox 13 stores the tools and spare parts required for testing for easy access by the operator. The connection port 14 realizes the data transmission or power connection between the host 1 and external equipment.

[0037] Reference Figure 1 , Figure 3 and Figure 6 The buffer mechanism 3 includes two fixing strips 301, which are used to stably connect the protective shell 302 to the main unit 1, thus achieving the fixed installation of the buffer mechanism 3. The bottoms of the two fixing strips 301 are respectively fixedly connected to the front and rear sides of the top of the main unit 1. This connection position can ensure that the buffer mechanism 3 provides comprehensive protection for the top of the main unit 1. The bottoms of the two fixing strips 301 are threadedly connected to the same protective shell 302. The protective shell 302 is used to wrap the telescopic rod 304 and the spring 303 to prevent the buffer components from being damaged by external dust or impact. The telescopic rod 304 is provided in the middle of the inner wall of the protective shell 302. The telescopic rod 304 is used to extend and retract during a collision. Deformation offsets the impact force, forming a double buffer with spring 303. Spring 303 is provided on both the left and right sides of the inner wall of the protective shell 302. Spring 303 is used to absorb impact energy through elastic deformation when a collision occurs, initially weakening the force on the main unit 1. Multiple heat sinks 11 are fixedly connected to the left and right sides of the main unit 1. Heat sinks 11 are used to conduct heat generated by the internal components of the main unit 1 to prevent the detection accuracy and service life of the equipment from being affected by excessive temperature. Screen 12 is fixedly connected to the top right side of the main unit 1. Screen 12 is used to display pantograph pressure detection data and equipment working status information in real time, which is convenient for operators to view and judge intuitively.

[0038] Specifically, in the buffer mechanism 3, the fixing strip 301 stably connects the protective shell 302 to the main unit 1 to achieve the fixed installation of the buffer mechanism 3. The connection between the fixing strip 301 and the main unit 1 ensures that the buffer mechanism 3 provides comprehensive protection for the top of the main unit 1. The protective shell 302 encloses the telescopic rod 304 and the spring 303 to prevent the buffer components from being damaged by external dust or impact. When there is a collision, the telescopic rod 304 offsets the impact force through telescopic deformation, forming a double buffer with the spring 303. When a collision occurs, the spring 303 absorbs the impact energy through elastic deformation, initially weakening the force on the main unit 1. The heat sink 11 dissipates the heat generated by the internal components of the main unit 1 to prevent the equipment from affecting the detection accuracy and service life due to excessive temperature. The screen 12 displays the pantograph pressure detection data and equipment working status information in real time, making it convenient for operators to view and judge intuitively.

[0039] Reference Figure 1 , Figure 5 and Figure 7 The limiting assembly 209 includes a limiting rod 2091, which is fixed to the inner wall of the lead screw 203, providing an installation reference and motion constraint for the limiting block 2092. The outer wall of the limiting rod 2091 is fixedly connected to the inner wall of the lead screw 203. This connection method ensures that the limiting rod 2091 and the lead screw 203 move synchronously, avoiding relative displacement from affecting the limiting effect. The bottom of the mounting shaft 201 is fixedly connected to the limiting block 2092, which is used to slide along the guide plate 2093, cooperating with the limiting rod 2091 to lock the position of the lead screw 203. The bottom of the limiting block 2092 is slidably connected to the guide plate 2093, which serves as the sliding surface for the limiting block 2092. The system provides a guiding path to ensure precise and stable limiting actions. Stabilizing plates 2 and 5 are fixedly connected to the bottom front and rear sides of the main unit 1. Stabilizing plates 2 and 5 are used to support the slide groove 6 and slider 2 and 7, providing installation support for the handle 8. The bottom of both stabilizing plates 2 and 5 is provided with slide groove 6. The slide groove 6 provides space and guidance for the sliding of slider 2 and 7, making it easy to adjust the position of the handle 8. Slider 2 and 7 are slidably connected to the inner wall of the slide groove 6. Slider 2 and 7 are used to drive the handle 8 to move along the slide groove 6, realizing adaptive adjustment of the position of the handle 8. The bottom of slider 2 and 7 is fixedly connected to the handle 8, which is used for the operator to hold, making it easy to carry the equipment or stabilize the main unit 1 during installation. It is suitable for the narrow operating space on the roof of hybrid vehicles.

[0040] Specifically, in the limiting component 209, the limiting rod 2091 and the inner wall of the lead screw 203 are fixed to provide an installation reference and motion constraint for the limiting block 2092. The connection between the limiting rod 2091 and the lead screw 203 ensures that the two move synchronously and avoids relative displacement from affecting the limiting effect. The limiting block 2092 slides along the guide plate 2093 to cooperate with the limiting rod 2091 to lock the position of the lead screw 203. The guide plate 2093 provides a guiding path for the sliding of the limiting block 2092 to ensure accurate and stable limiting action. The second stabilizing plate 5 carries the slide groove 6 and the second slider 7 to provide installation support for the handle 8. The slide groove 6 provides space and guidance for the sliding of the second slider 7 to facilitate adjustment of the position of the handle 8. The second slider 7 drives the handle 8 to move along the slide groove 6 to achieve adaptive adjustment of the position of the handle 8. The handle 8 is provided for the operator to hold and carry the equipment or stabilize the main unit 1 during installation to adapt to the narrow operating space on the roof of the hybrid vehicle.

[0041] Working principle: The operator first places the main unit 1 in the pantograph detection area and rotates the mounting shaft 201. The top of the mounting shaft 201 is rotatably connected to the bottom of the inner wall of the main unit 1. When the sliding plate 202 fixed at the bottom rotates with the mounting shaft 201, the lead screw 203 at the bottom of its inner wall will synchronously drive the sliding plate 202 to make slight adjustments in the horizontal direction. At the same time, the sliders 204 on the front and rear sides of the bottom of the mounting shaft 201 slide along the slide rail 205. To accommodate the difference in pantograph head width for different vehicle models, the hooks 207 on both sides are aligned with the pantograph mounting holes. Meanwhile, the fixed plate is rotated. The stabilizing plate 208 on the side away from the fixed plate 206 can be rotated to contact the horizontal plane, increasing the ground contact area. The limiting rod 2091 is fixed to the inner wall of the lead screw 203 and slides along the guide plate 2093 through the limiting block 2092 to lock the position of the lead screw 203 and prevent displacement after installation. The stabilizing plate 5 at the bottom of the main unit 1 cooperates with the slider 7. The operator can slide the slider 7 to adjust the position of the handle 8. In the narrow space of the roof of the hybrid vehicle, the main unit 1 is stabilized by the handle 8 without the need for shims for leveling or straps for fixing.

[0042] Furthermore, when the device collides or falls accidentally on the roof of a hybrid vehicle, the buffer mechanism 3 activates first to provide protection. The protective shell 302 is connected to the top of the main unit 1 via the fixing strip 301. The springs 303 on the left and right sides of its inner wall absorb the impact energy of the protective shell 302. At the same time, the telescopic rod 304 in the middle of the inner wall extends and retracts synchronously, forming a double buffer with the springs 303 to prevent the main unit 1 from directly bearing the impact. This solves the problem of existing devices being damaged due to lack of buffer. During testing, the measuring hook 9 slides along the sliding hole 4 to connect with the pantograph. If the measuring hook 9 is misaligned or the device is tilted due to a collision, the alarm 10 on the left rear side of the main unit 1 will immediately sound an audible and visual alarm to remind the operator to make timely adjustments. During the testing process, the heat sinks 11 on the left and right sides of the main unit 1 continuously dissipate heat. The screen 12 displays the buffer status and test data in real time. The toolbox 13 can store spare buffer components, and the connection port 14 ensures stable data transmission, comprehensively improving the safety and reliability of the device in collision scenarios.

[0043] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An adjustable pantograph pressure detector for electric locomotives, comprising a main unit (1), characterized in that: The bottom of the host (1) is provided with an installation mechanism (2), the outer wall of the host (1) is provided with a buffer mechanism (3), the buffer mechanism (3) is used to buffer the impact force of the collision, and a sliding hole (4) is opened on the top left side of the host (1). The installation mechanism (2) includes an installation shaft (201), the top end of which is rotatably connected to the bottom of the inner wall of the host (1), a slide plate (202) is fixedly connected to the bottom end of the installation shaft (201), a lead screw (203) is slidably connected to the bottom of the inner wall of the slide plate (202), a slider (204) is fixedly connected to the front and rear sides of the bottom of the installation shaft (201), a slide rail (205) is slidably connected to the inner walls of the two sliders (204), a fixing plate (206) is fixedly connected to the left and right ends of the two slide rails (205), a hook (207) is fixedly connected to the front and rear sides of the two fixing plates (206), a stabilizing plate (208) is rotatably connected to the side of the two fixing plates (206) that is far apart from each other, and a limit component (209) is provided on the inner wall of the lead screw (203).

2. The adjustable electric locomotive pantograph pressure detector according to claim 1, characterized in that: The buffer mechanism (3) includes two fixing bars (301). The bottoms of the two fixing bars (301) are respectively fixedly connected to the front and rear sides of the top of the host (1). The bottoms of the two fixing bars (301) are threadedly connected to the same protective shell (302). A telescopic rod (304) is provided at the middle of the inner wall of the protective shell (302). Springs (303) are provided on the left and right sides of the inner wall of the protective shell (302).

3. The adjustable electric locomotive pantograph pressure detector according to claim 1, wherein: The limiting component (209) includes a limiting rod (2091), the outer wall of which is fixedly connected to the inner wall of the lead screw (203), and a limiting block (2092) is fixedly connected to the bottom of the mounting shaft (201). A guide plate (2093) is slidably connected to the bottom of the limiting block (2092).

4. The adjustable electric locomotive pantograph pressure detector of claim 1, wherein: The bottom front and rear sides of the host (1) are fixedly connected to a second stabilizing plate (5), and the bottom of the two second stabilizing plates (5) are provided with a sliding groove (6).

5. The adjustable electric locomotive pantograph pressure detector according to claim 4, characterized in that: The inner wall of the slide (6) is slidably connected to a slider two (7), and the bottom of the slider two (7) is fixedly connected to a handle (8).

6. The adjustable pantograph pressure detector for electric locomotives according to claim 1, characterized in that: The inner wall of the sliding hole (4) is slidably connected to a measuring hook (9), and an alarm (10) is provided on the rear left side of the main unit (1).

7. The adjustable pantograph pressure detector for electric locomotives according to claim 1, characterized in that: Multiple heat sinks (11) are fixedly connected to the left and right sides of the host (1), and a screen (12) is fixedly connected to the top right side of the host (1).

8. The adjustable pantograph pressure detector for electric locomotives according to claim 1, characterized in that: A toolbox (13) is fixedly connected to the rear right end of the host (1), and a connection port (14) is provided on the front left end of the host (1).

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