Contact wheel assembly and rolling type lower contact collector shoe adopting same

Abstract

The invention provides a trolley wheel assembly and a rolling type lower contact collector shoe using the trolley wheel assembly, the trolley wheel assembly comprises a first trolley wheel support, the first trolley wheel support is provided with two second trolley wheel supports, the second trolley wheel supports are provided with trolley wheel parts, and the trolley wheel parts are connected with the trolley wheel supports. The trolley wheel part comprises a trolley wheel, a carbon brush arranged in the trolley wheel and a fixing rod which is installed on the second trolley wheel support and arranged in the carbon brush in a penetrating mode. The invention has the following beneficial effects: the contact wheel is used for replacing a carbon slide plate, so that the original surface-to-surface contact between the carbon slide plate and the contact rail is changed into line-to-surface contact, sliding friction is changed into rolling friction, and the friction loss is reduced; meanwhile, compared with a carbon sliding plate, the contact wheel is more uniform in abrasion and better in heat dissipation condition, and the heat accumulation condition caused by abrasion is improved; and a pair of trolley wheels is adopted to cope with electric sparks generated by instant derailment caused by sudden load change or track irregularity in train operation.

Description

Technical Field

[0001] The present invention relates to the technical field of friction performance between a collector shoe and a contact rail, and in particular to a contact wheel assembly and a rolling lower contact collector shoe using the contact wheel assembly. Background Art

[0002] With the continuous development of society and the continuous expansion of cities, the congestion faced by residents and the pollution of automobile exhaust are becoming more and more serious. Rail transit has become the preferred mode of travel for people. The contact rail-collector shoe system is one of the main current collection forms adopted by the urban rail transit traction power supply system. The collector shoe is the current collection device in the rail shoe system. As a channel for subway vehicles to obtain electricity from the outside world, the collector shoe is usually installed on both sides of the bottom of the vehicle body. It is mainly composed of four parts: base, swing arm, locking and retraction mechanism and cable line; the base is mainly used to fix the collector shoe on the vehicle body and fix other components. The base also plays the role of dustproof, shockproof and isolation protection; the swing arm is a long strip structure made of steel, one end of which is under the base. The shaft extends out from the swing arm, and the other end is used to fix the carbon slide board. The swing arm is mainly used to connect the collector shoe and the contact rail, and transmit electric energy from the carbon slide board to the collector shoe; the cable is used to transmit electric energy, one end of which is connected to the carbon slide board, and the other end is connected to the vehicle's power system. The cable is required to be able to move a certain range with the swing arm; in order to ensure that the carbon slide board can have good contact with the contact rail when the vehicle is running and to achieve the best current collection effect, the contact pressure of the carbon slide board to the standard static pressure of the contact rail is generally controlled at 140N, and the left and right error is within 20N.

[0003] Compared with the pantograph system, the rail shoe system has the advantages of simple structure, small size and light weight, small wind resistance during driving, and lower comprehensive construction cost than the pantograph system. However, using the collector shoe as a current collecting device also has new problems: 1. The sliding wear between the carbon slide plate and the contact rail is relatively large. Unlike the line-to-surface friction between the carbon slide plate and the contact line in the pantograph system, the friction between the carbon slide plate and the contact rail belongs to surface-to-surface friction with a high friction coefficient; 2. The contact part between the carbon slide plate surface of the collector shoe and the third rail hardly changes, which causes the carbon slide plate of the third rail structure to wear faster, and long-term friction will cause heat accumulation inside it, causing the physical and electrical properties of the carbon slide plate to change, affecting the overall current collecting effect, which also makes it difficult to further increase the speed of vehicles collecting current on the third rail; 3. During the train driving, the carbon slide plate and the contact rail may be momentarily off the track, resulting in electric sparks, damaging the carbon slide plate, and affecting its service life.

[0004] Domestic and foreign research mainly simulates the movement between the contact rail and the collector shoe, and conducts simulation experiments by constantly changing the contact conditions. Finally, the experimental results are summarized to find the best parameters suitable for the rail shoe system, so as to continuously improve the friction problem of the rail shoe system; therefore, the current research on the collector shoe is mainly focused on simulating the movement between the rail shoes, establishing a simulation model, and conducting simulation experiments by constantly changing the contact conditions. There are few improvements to the collector shoe from a structural perspective. Therefore, the present invention proposes a collector shoe with a new structure based on the improved collector shoe structure. Summary of the invention

[0005] In view of the shortcomings of the prior art mentioned above, the object of the present invention is to provide a contact wheel assembly and a rolling lower contact collector shoe using the contact wheel assembly, so as to solve the problem in the prior art that the friction between the carbon slide plate and the contact rail is surface friction and has a high friction coefficient.

[0006] To achieve the above objectives and other related objectives, the present invention provides the following technical solutions:

[0007] A trolley assembly comprises a first trolley bracket, two second trolley brackets are mounted on the first trolley bracket, a trolley component is mounted on the second trolley bracket, the trolley component comprises a trolley, a carbon brush arranged in the trolley, and a fixing rod mounted on the second trolley bracket and passing through the carbon brush, two fixing rings located on both sides of the carbon brush are also provided on the outer surface of the fixing rod, a bearing mounted on the outer surface of the fixing rod is provided between the fixing ring and the second trolley bracket, and the outer surface of the bearing is connected to the inner surface of the trolley.

[0008] The above technical solution uses a contact wheel instead of a carbon slide board, thereby converting the original surface contact between the carbon slide board and the contact rail into line contact, converting the sliding friction into rolling friction, and reducing its friction loss; at the same time, the contact wheel wears more evenly than the carbon slide board, and the heat dissipation conditions are better, and the heat accumulation caused by wear is improved; and a pair of contact wheels can be used to cope with the electric sparks caused by sudden load changes during train operation or uneven tracks that lead to instantaneous derailment.

[0009] In one embodiment of the present invention, the contact wheel is made of graphite, a support cage is installed inside the contact wheel, a wear-resistant conductive layer is provided on the outer surface of the contact wheel, and a graphite lubricating layer is provided on the inner surface of the contact wheel.

[0010] In one embodiment of the present invention, the outer surface of the carbon brush contacts the inner surface of the contact wheel through a first spring, a circular hole for placing the first spring is opened in the fixing rod, and the inner surface of the carbon brush is connected to the cable through a contact head.

[0011] In one embodiment of the present invention, the carbon brush comprises a carbon brush block and two protrusions integrally formed with the carbon brush block, the carbon brush block is arc-shaped, and limiting grooves matching the protrusions are provided on opposite sides of the two fixing rings.

[0012] A rolling lower contact collector shoe using the contact wheel assembly comprises a base, the side of the base is connected to a swing arm frame movably connected to the first contact wheel bracket through a rotating assembly, the base is provided with a driving assembly for driving the swing arm frame to swing, the driving assembly comprises a driving cylinder mounted on the base, a gear component and a connecting rod mounted on the driving cylinder, one end of the connecting rod is movably connected to the gear component, and the other end of the connecting rod is movably connected to the swing arm frame; under the action of the driving cylinder, this technical solution drives the connecting rod to move up and down through the gear component, thereby causing the swing arm frame to swing up and down.

[0013] In one embodiment of the present invention, the rotating assembly includes two mounting blocks installed on the side of the base close to the swing arm frame, and a rotating shaft is passed through the two mounting blocks. The outer surface of the rotating shaft is movably connected to a connecting frame located between the two mounting blocks and installed on the swing arm frame.

[0014] In one embodiment of the present invention, the driving assembly also includes a second spring and a third spring located on both sides of the connecting rod, one end of the second spring and the third spring is movably connected to the base, and the other end of the second spring and the third spring is movably connected to the swing arm frame.

[0015] In one embodiment of the present invention, the gear component includes a toothed plate mounted on the telescopic rod of the driving cylinder and a gear mounted on the base and meshing with the toothed plate. The side of the gear away from the base is movably connected to the connecting rod via a connecting piece. A sliding rod is also installed on the base and is located below the driving cylinder and is slidably connected to the toothed plate. This technical solution can drive the toothed plate to slide on the sliding rod by extending and shortening the telescopic rod of the driving cylinder, thereby causing the gear to rotate, thereby driving the connecting rod to move up and down.

[0016] As described above, a contact wheel assembly and a rolling lower contact collector shoe using the contact wheel assembly of the present invention have the following beneficial effects: the present invention uses a pair of contact wheels to replace the traditional sliding slide plate, and at the same time installs a carbon brush inside the contact wheel, so that the outer surface of the carbon brush directly contacts the contact wheel to receive electricity, and the inner surface connects the cable to supply power to the vehicle through the contact head. Compared with the traditional sliding slide plate, the contact wheel greatly reduces the friction between the contact rail and the contact rail. At the same time, the contact wheel wears more evenly than the carbon slide plate, and the heat dissipation condition is better, and the heat accumulation caused by wear is improved; and the design of the two contact wheels can ensure that when the vehicle encounters wheel-rail separation due to uneven rail surface or instantaneous load impact during driving, at least one contact wheel is in good contact with the contact rail. At the same time, the two contact wheels have an extra degree of freedom and can rotate at a certain angle. Therefore, when the contact rail and the ground have a certain slope, they can also run smoothly, so the present invention has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a left front perspective schematic diagram of a trolley assembly in a first embodiment of the present invention;

[0018] Figure 2 A right front perspective view of a trolley assembly in a first embodiment of the present invention is shown;

[0019] Figure 3 A right front perspective schematic diagram showing a trolley assembly without a trolley installed in the first embodiment of the present invention;

[0020] Figure 4 The diagram is a left top perspective view of the trolley assembly in the first embodiment of the present invention without the trolley installed;

[0021] Figure 5 It is a right front perspective schematic diagram showing the trolley assembly in the first embodiment of the present invention without the trolley and the carbon brush installed;

[0022] Figure 6 A perspective schematic diagram of a trolley in a trolley assembly according to a first embodiment of the present invention is shown;

[0023] Figure 7 Shown is a three-dimensional schematic diagram of a carbon brush in a trolley assembly in a first embodiment of the present invention;

[0024] Figure 8 It is a left front perspective schematic diagram of a rolling lower contact collector shoe using the contact wheel assembly in a second embodiment of the present invention;

[0025] Fig. 9 It is a rear perspective schematic diagram of a rolling lower contact collector shoe using the contact wheel assembly in the second embodiment of the present invention;

[0026] Fig.10 It is a schematic diagram showing the force analysis when the contact wheel in the rolling lower contact collector shoe using the contact wheel assembly contacts the contact rail in the second embodiment of the present invention;

[0027] Fig.11 Shown is a schematic diagram of the mechanical properties of ordinary carbon steel in the rolling lower contact collector shoe using the contact wheel assembly in the second embodiment of the present invention.

[0028] Component number description

[0029] 1. First trolley bracket; 2. Second trolley bracket; 3. trolley component; 301. trolley; 302. Carbon brush; 3021. Carbon brush block; 3022. Bump; 303. Fixed rod; 4. Fixed ring; 5. Bearing; 6. Round hole; 7. Limiting groove; 8. Base; 9. Rotating assembly; 901. Mounting block; 902. Rotating shaft; 903. Connecting frame; 10. Swing arm frame; 11. Driving assembly; 1101. Driving cylinder; 1102. Gear component; 1103. Connecting rod; 1104. Second spring; 1105. Third spring; 12. Tooth plate; 13. Gear; 14. Sliding rod. DETAILED DESCRIPTION

[0030] The following specific embodiments illustrate the implementation of the present invention, and those familiar with the technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0031] See also Figures 1 to 7 A first embodiment of the present invention relates to a trolley assembly, comprising a first trolley bracket 1, on which two second trolley brackets 2 are mounted, on which a trolley component 3 is mounted, the trolley component 3 comprising a trolley 301, a carbon brush 302 arranged in the trolley 301 and a fixing rod 303 mounted on the second trolley bracket 2 and passing through the carbon brush 302, and two fixing rings 4 located on both sides of the carbon brush 302 are also provided on the outer surface of the fixing rod 303; wherein, the second trolley bracket 2 is used to fix the trolley 301 and the carbon brush 302, the first trolley bracket 1 is mounted on the swing arm bracket 10 described below, and in order to prevent dust from entering the interior of the trolley 301, the support baffles on both sides of the second trolley bracket 2 are slightly larger than the diameter of the trolley 301, and considering the overall rigidity of the bracket, the trolley bracket is not required to use insulating materials.

[0032] The material of the contact wheel 301 is graphite, and a support cage is installed inside the contact wheel 301. The outer surface of the contact wheel 301 is provided with a wear-resistant conductive layer, and the inner surface of the contact wheel 301 is provided with a graphite lubricating layer, wherein the contact wheel 301 is a cylindrical structure with graphite as the main material, and a steel cage is embedded inside as a support to ensure its strength, that is, the material of the support cage is steel, and the graphite lubricating layer is used to reduce the gap and friction when contacting with the carbon brush 302; a bearing 5 installed on the outer surface of the fixed rod 303 is provided between the fixing ring 4 and the second contact wheel bracket 2, and the outer surface of the bearing 5 is connected to the inner surface of the contact wheel 301.

[0033] The carbon brush 302 is a small block made of graphite. The outer surface of the carbon brush 302 directly contacts the contact wheel 301 to receive electricity, and the inner surface of the carbon brush 302 supplies power to the vehicle through the contact head connecting cable; the outer surface of the carbon brush 302 contacts the inner surface of the contact wheel 301 through the first spring, and a circular hole 6 for placing the first spring is opened in the fixed rod 303, wherein the first spring provides an outward pre-tightening force for the carbon brush 302 to ensure the contact quality; the carbon brush 302 includes a carbon brush block 3021 and two protrusions 3022 integrally formed with the carbon brush block 3021, the carbon brush block 3021 is in the shape of an arc, and the opposite sides of the two fixing rings 4 are provided with limiting grooves 7 matching the protrusions 3022, wherein the protrusions 3022 of the carbon brush 302 are assembled in the limiting grooves 7 to ensure that they will not rotate with the rotation of the contact wheel 301 during movement.

[0034] Specifically, when the contact wheel 301 contacts the contact rail, the contact wheel 301 rotates under the action of the bearing 5, and the rotating contact wheel 301 contacts the outer surface of the carbon brush 302. The carbon brush 302 is energized by continuous contact friction, and then the contact head on the inner surface of the carbon brush 302 is connected to the cable to supply power to the vehicle.

[0035] More specifically, considering that the contact between the contact wheel 301 and the contact rail is line-surface contact, when the contact rail surface is uneven or has seams, the instantaneous load impact may cause the contact wheel 301 to separate from the contact rail and generate sparks. The instantaneous high temperature will damage the contact wheel 301 and also make the input voltage unstable, damaging the vehicle's electrical system. In order to alleviate this problem, the present invention provides two contact wheels 301, so that when the vehicle encounters the above problem during operation, at least one contact wheel 301 is in good contact with the contact rail, and the other contact wheel 301 is short-circuited because the air resistance value is much greater than the graphite resistance value, thereby effectively reducing the probability of spark generation and stabilizing the input voltage. At the same time, the double contact wheel structure has an additional degree of freedom and can rotate at a certain angle, so it can also operate smoothly when the contact rail and the ground have a certain slope.

[0036] See also Figure 8 and Fig. 9A second embodiment of the present invention relates to a rolling lower contact collector shoe using the contact wheel assembly, including a base 8, a side of the base 8 is connected to a swing arm frame 10 movably connected to the first contact wheel bracket 1 through a rotating assembly 9, the rotating assembly 9 includes two mounting blocks 901 installed on the side of the base 8 close to the swing arm frame 10, a rotating shaft 902 is passed through the two mounting blocks 901, and the outer surface of the rotating shaft 902 is movably connected to a connecting frame 903 located between the two mounting blocks 901 and installed on the swing arm frame 10.

[0037] The base 8 is provided with a driving assembly 11 for driving the swing arm frame 10 to swing. The driving assembly 11 includes a driving cylinder 1101 installed on the base 8, a gear component 1102 and a connecting rod 1103 installed on the driving cylinder 1101, one end of the connecting rod 1103 is movably connected to the gear component 1102, and the other end of the connecting rod 1103 is movably connected to the swing arm frame 10. The driving assembly 11 also includes a second spring 1104 and a third spring 1105 located on both sides of the connecting rod 1103. 4 and one end of the third spring 1105 are movably connected to the base 8, and the other ends of the second spring 1104 and the third spring 1105 are movably connected to the swing arm frame 10. The gear component 1102 includes a toothed plate 12 installed on the telescopic rod of the driving cylinder 1101 and a gear 13 installed on the base 8 and meshing with the toothed plate 12. The side of the gear 13 away from the base 8 is movably connected to the connecting rod 1103 through a connecting piece. A sliding rod 14 is also installed on the base 8 and is located below the driving cylinder 1101 and is slidably connected to the toothed plate 12.

[0038] For the rolling lower contact collector shoe adopting the contact wheel assembly of the present invention, the base 8, rotating assembly 9 and driving assembly 11 in the rolling lower contact collector shoe all refer to the prior art. For details, please refer to Cao Haiping's "Shanghai Metro Line 17 Current Collector Fault Analysis and Improvement Plan", see Rail Transit Equipment and Technology No. 6, November 2021, the article number is: 2095-5251 (2021) 06-0030-03.

[0039] Specifically, the first contact wheel bracket 1 is installed on the swing arm frame 10. The swing arm frame 10 is mainly used to carry the flow receiving component of the collector shoe, and is also connected to the locking and retracting mechanism for controlling the swinging thereof, that is, the driving component 11. Since the flow receiving component is subjected to the static load caused by the locking force and the impact load caused by the uneven track surface when the vehicle is running, the strength and toughness requirements of the swing arm frame 10 are relatively high. In order to reduce the cost and difficulty of the manufacturing process, the swing arm frame 10 is divided into a part fixed to the shaft and a part fixed to the flow receiving component, that is, a swing arm fixing part and a swing arm main body part. This structure can reduce the cost without reducing the overall strength and simplify the assembly process of the swing arm. The swing arm fixing part is composed of two identical parts, which are mainly used to fix the swing arm main body and the shaft. Each part is fixed to the shaft through two deep groove ball bearings; the swing arm main body is mainly used to carry the flow receiving component of the collector shoe, and is also connected to the locking and retracting mechanism for controlling the swinging thereof.

[0040] When there is a locking force of 100N between the trolley and the steel-aluminum composite rail, the stress, strain and displacement are mainly concentrated in the trolley bracket part and the upper part of the trolley 301. For details, please refer to Fig.10 Therefore, the use of a pair of trolleys can effectively reduce the stress concentration. At the same time, a steel cage is embedded in the graphite to ensure its strength. The analysis material is ordinary carbon steel. For the mechanical properties of ordinary carbon steel, please refer to Fig.11 .

[0041] More specifically, the present invention can reduce friction loss: by adopting a rolling contact method, friction is converted into rolling, which greatly reduces friction loss and extends the service life of the system; the present invention has good wear uniformity and heat dissipation: the contact wheel 301 wears more evenly and has good heat dissipation conditions, which effectively reduces the heat accumulation problem caused by wear and improves the stability of the system; the present invention has strong adaptability: the design of a pair of contact wheels 301 can adapt to the sudden load change during train operation or the instantaneous derailment caused by uneven tracks, thereby improving the safety and reliability of the system; the present invention has a stable power supply: through the contact between the carbon brush 302 and the contact wheel 301, a stable supply of power is achieved, and at the same time, the design of the carbon brush 302 ensures the contact quality and conductive performance; the present invention has low maintenance cost: the uniform wear design is adopted to greatly reduce the maintenance cost of the system, reduce the maintenance cycle and repair costs; so the present invention is easy to promote and use.

[0042] In summary, the present invention uses a pair of contact wheels 301 to replace the traditional sliding slide plate, and at the same time installs a carbon brush 302 inside the contact wheel 301, so that the outer surface of the carbon brush 302 directly contacts the contact wheel 301 to receive electricity, and the inner surface is connected to the cable through the contact head to supply power to the vehicle; compared with the traditional sliding slide plate, the contact wheel 301 greatly reduces the friction between the contact rail and the contact rail. At the same time, compared with the carbon slide plate, the contact wheel 301 wears more evenly, has better heat dissipation conditions, and improves the heat accumulation caused by wear; and the design of the two contact wheels 301 can ensure that when the vehicle encounters uneven rail surface or instantaneous When the wheel-rail is separated due to load impact, at least one contact wheel 301 is in good contact with the contact rail. At the same time, the two contact wheels 301 can rotate at a certain angle because of the extra degree of freedom. Therefore, they can also run smoothly when there is a certain slope between the contact rail and the ground. Therefore, the present invention has broad application prospects and can be widely used in the field of rail transit, such as the power collection systems of various means of transportation such as subways, trams, high-speed railways, etc. Its superior performance and stable and reliable characteristics will greatly improve the operation efficiency and safety of the vehicle, while reducing the maintenance cost of the system. It has broad market prospects and promotion value.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. All equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A trolley assembly, characterized in that: The invention comprises a first trolley bracket (1), two second trolley brackets (2) are mounted on the first trolley bracket (1), a trolley component (3) is mounted on the second trolley bracket (2), the trolley component (3) comprises a trolley (301), a carbon brush (302) arranged in the trolley (301), and a fixing rod (303) mounted on the second trolley bracket (2) and inserted into the carbon brush (302), two fixing rings (4) located on both sides of the carbon brush (302) are also arranged on the outer surface of the fixing rod (303), a bearing (5) mounted on the outer surface of the fixing rod (303) is arranged between the fixing ring (4) and the second trolley bracket (2), and the outer surface of the bearing (5) is connected to the inner surface of the trolley (301).

2. A trolley assembly according to claim 1, characterized in that: The material of the contact wheel (301) is graphite. A support cage is installed inside the contact wheel (301). A wear-resistant conductive layer is provided on the outer surface of the contact wheel (301), and a graphite lubricating layer is provided on the inner surface of the contact wheel (301).

3. A trolley assembly according to claim 1, characterized in that: The outer surface of the carbon brush (302) contacts the inner surface of the contact wheel (301) through a first spring, a circular hole (6) for placing the first spring is provided in the fixing rod (303), and the inner surface of the carbon brush (302) is connected to the cable through a contact head.

4. A trolley assembly according to claim 1, characterized in that: The carbon brush (302) comprises a carbon brush block (3021) and two protrusions (3022) integrally formed with the carbon brush block (3021); the carbon brush block (3021) is arc-shaped; and limiting grooves (7) matching the protrusions (3022) are provided on opposite sides of the two fixing rings (4).

5. A rolling lower contact collector shoe using the contact wheel assembly according to any one of claims 1 to 4, characterized in that: The invention comprises a base (8), the side of the base (8) is connected to a swing arm frame (10) movably connected to the first contact wheel bracket (1) through a rotating assembly (9), the base (8) is provided with a driving assembly (11) for driving the swing arm frame (10) to swing, the driving assembly (11) comprises a driving cylinder (1101) installed on the base (8), a gear component (1102) installed on the driving cylinder (1101) and a connecting rod (1103), one end of the connecting rod (1103) is movably connected to the gear component (1102), and the other end of the connecting rod (1103) is movably connected to the swing arm frame (10).

6. The rolling lower contact collector shoe using the contact wheel assembly according to claim 5, characterized in that: The rotating assembly (9) comprises two mounting blocks (901) mounted on the side of the base (8) close to the swing arm frame (10), a rotating shaft (902) passing through the two mounting blocks (901), and an outer surface of the rotating shaft (902) is movably connected to a connecting frame (903) located between the two mounting blocks (901) and mounted on the swing arm frame (10).

7. The rolling lower contact collector shoe using the contact wheel assembly according to claim 5, characterized in that: The driving assembly (11) further comprises a second spring (1104) and a third spring (1105) located on both sides of the connecting rod (1103), one end of the second spring (1104) and the third spring (1105) being movably connected to the base (8), and the other end of the second spring (1104) and the third spring (1105) being movably connected to the swing arm frame (10).

8. The rolling lower contact collector shoe using the contact wheel assembly according to claim 5, characterized in that: The gear component (1102) comprises a toothed plate (12) mounted on the telescopic rod of the driving cylinder (1101) and a gear (13) mounted on the base (8) and meshing with the toothed plate (12); the side of the gear (13) away from the base (8) is movably connected to the connecting rod (1103) via a connecting piece; and a sliding rod (14) is also mounted on the base (8) and is located below the driving cylinder (1101) and is slidably connected to the toothed plate (12).

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