2.2.2 Hanging Wheel
1.Basic Structure and Function of Hanging Wheels
(1)Basic structure
The hanging wheel is a special tool for driving on overhead conductors,and Fig.2-24 shows the structure of the manual hanging wheel for double bundle conductors.It consists of swing frame,front road wheel,auxiliary wheel,front road wheel handle,auxiliary wheel handle,chain,chain cover,cushion,backrest,frame,rear road wheel handle,rear road wheel,bumper joint,bumper,chain gear,pedal and brake.Fig.2-25 shows a single-conductor hanging wheel.
Fig.2-24 Structure of Manual Hanging Wheel for Double Bundle Conductors
1-swing frame;2-front road wheel;3-auxiliary wheel;4-front road wheel handle;5-auxiliary wheel handle;6-chain;7-chain cover;8-cushion;9-backrest;10-framework;11-rear road wheel handle;12-rear road wheel;13-bumper joint;14-bumper;15-chain gear 16-pedal;17-brake
Fig.2-25 Single-conductor Hanging Wheel
(2)Main functions
The hanging wheel is used as a vehicle when the spacer,anti-vibration hammer and other accessories of the transmission line are installed or repaired,or the line crimping pipe is inspected,replaced,and maintained.
2.Basic Type and Technical Parameters of Hanging Wheels
(1)Basic type
①According to the number of conductors on which the wheel walks:There are single-conductor,double-bundle conductor,three-bundle conductor and four-bundle conductor hanging wheels.A single-conductor hanging wheel generally uses two wheels;the other multi-bundle conductor hanging wheels have 4 to 10 wheels,respectively.
②According to the driving mode of the hanging wheels:There are man-powered and motor-powered hanging wheels.Most of the man-powered hanging wheels use a pedal-like driving method like the bicycle;the motor-powered hanging wheels use a small gasoline engine as the power and are driven by hydraulic transmission or chain transmission.
③According to the overall structure of the hanging wheel:It can be divided into two types:basket type and frame type hanging wheels.The transmission of the basket type is installed in an easy-to-purchase metal basket,and the operator stands in the basket while working.The shape of the frame-type hanging wheel is similar to that of a bicycle or a scooter,and the operator sits on the cushion to work.
Fig.2-26 shows the pedal type hanging wheel of double-bundle conductor,and Fig.2-27 shows several common hanging wheels.
Fig.2-26 Pedal Type Hanging Wheel of Bundled Conductor
Fig.2-27 Tackle Diagram
(a)SFS-1×150 single-conductor hanging wheel;(b)SFC-2×150 double-bundle conductor hanging wheel;(c)man-powered pedal type four-bundle conductor hanging wheel;(d)four-conductor eight-sheave frame type motor-powered hanging wheel
1-long pin axle;2-hinged connecting plate;3-hydraulic cylinder;4-driven wheel arm;5-pin shaft;6-plug pin;7-conductor;8-drive wheel;9-distance measuring device;10-cable clamp brake;11-frame;12-hydraulic pump;13-plug pin for preventing falling;14-hydraulic motor;15-anti-falling chain;16-drive wheel arm;17-driven wheel;18-operation box
(2)Performance data
①Product code
The product code consists of voltage class,hanging wheel symbol,characteristics,and applicable range,such as F500-SB-ZA(B).
Wherein:F indicates the hanging wheel;
500 indicates 500kV;
SB indicates double drive roll type;
Z indicates linear type;
Aindicates a maximum slope of 14°;
B-maximum slope of 20°.
②Technical requirements
a.Material requirements:The hanging wheel shall be made from high strength,light weight and non-brittle materials in accordance with national standards.
b.Rated load:The rated load of the hanging wheel shall be no less than 900N.(https://www.daowen.com)
c.Safety:The hanging wheel shall have double safety devices.
③Driving performance requirements
a.The hanging wheel shall be able to pass the spacer,the anti-vibration hammer and the suspension insulator string.
b.The active road wheel sheave groove shall be inlaid with conductive abrasion resistant rubber.
c.There shall be no charging or discharging when driving on an alive line;
d.The hanging wheel distance shall be able to vary within 450(-30 to+50)mm.
e.The dimensions of the hanging wheel shall be compact and not greater than the data shown in Fig.2-2-8.
f.The climbing ability of the A-type hanging wheel shall reach 14°,and the climbing ability of the B-type hanging wheel shall reach 20°.
g.The hanging wheel shall be equipped with the forward gear,the reverse gear and the neutral gear.When it is reversed,it can also pass the spacer,the anti-vibration hammer and the suspension insulator string.The B-type hanging wheel shall be equipped with high speed and low speed gears.
④Structural requirements:The structure of the hanging wheel shall be light,easy to operate,transport and store.The weight of the A-type hanging wheel is below 40kg,and
the weight of the B-type hanging wheel is below 50kg.
⑤Process requirements:The surface of parts of the hanging wheel shall be free of sharp edges and corners,and the interfaces shall be rounded;the processing,heat treatment and assembly shall be carried out in accordance with the provisions of the national standard,and the surface of the material shall be subjected to anti-corrosion treatment.
3.Inspection Items Before Use of the Hanging Wheel
(1)Visual inspection shall be carried out before use,including inspection of the overall shape,materials,signs,and technology.
(2)Before use,the hanging wheel shall be inspected to see if the structure of each part is firm and reliable,if the transmission structure is flexible,and if the safety devices are intact and reliable.
(3)Before use,inspect if the hanging wheel is subjected to mechanical load test and if the test cycle is within the validity period.
4.Precautions for Use of Hanging Wheel
(1)When the operator is working on...,the cross-sectional area of the conductor and ground wire shall satisfy the requirement that it shall not be less than 120mm2 for steel-cored aluminum stranded conductors,not be less than 50mm2 for steel strands,and not be less than 95mm2 for copper strands.
(2)In any of the following cases,the work shall be carried out after verification and approval by the chief engineer of the unit,including:work on the conductor and ground wire in the isolated span;work on the conductor and ground wire with broken strands;work on the ground wire corroded;work on conductors and ground wires with small cross sections or other models;work on conductors or ground wires by more than two people.
(3)Before hanging the ladder(or hanging wheel)on the conductor and ground wire,the operator must check the fastening of the conductor and ground wire at the pole and tower at both ends of the span.After the hanging ladder(or the hanging wheel)is loaded,the minimum distance between the ground wire and the human body to the electrified body is 0.5m greater than the minimum safe distance between the human body and the electrified body,and the minimum distance between the conductor and the human body to the crossed power line is 1.0m greater than the minimum safe distance between the human body and the electrified body.
(4)It is strictly forbidden to hang ladders(or hanging wheels)on the porcelain cross arm line.Before the ladders(or hanging wheels)hung on the line are rotated,the cross arm shall be fixed.
5.Precautions for Storage of Hanging Wheel
(1)The hanging wheels shall be stored in a well-ventilated and dry environment,and put on shelves.
(2)When the hanging wheel is not used for a long time,it shall be cleaned and coated with anti-rust oil to avoid rust.
6.Preventive Test of the Hanging Wheel
The preventive test of the hanging wheel includes visual inspection,stepping test,static load test,dynamic load test,bumper test and brake test,and the contents are as follows.
(1)Mainly inspect the shape,materials,technologies and signs of the hanging wheel,and the frequency is once a year.
(2)Stepping test.Under the rated load of 900N,the stepping of the hanging wheel on the analog line shall be normal,and it can smoothly pass the spacer,the anti-vibration hammer and the suspension insulator string in the analog line.The frequency is once a year.
(3)Static load test.A load of 2250N is applied to the cushion of the hanging wheel and it lasts 5 minutes on the analog line.The cushion of the hanging wheel shall be complete,good,and free of permanent deformation.The test cycle is 1 year.
(4)Dynamic load test.A load of 900N(including the operator's load)is applied to the cushion of the hanging wheel,and it can step on the analog line back and forth three times normally,which is equipped with a spacer,an anti-vibration hammer and a suspension insulator string.The test cycle is 1 year.
(5)Bumper test.The front and rear active road wheels on the side of the hanging wheel are disengaged from the conductors,so that one side of the two bumpers is directly placed on the conductors,and it is normal when the load of 1350N is applied,without permanent deformation.The test cycle is 1 year.
(6)Brake test.The braking performance of the hanging wheel shall be good,and the test carried out in the following ways shall meet the requirements.For the type A hanging wheel,when it bears a person on a slope ofα=14°(total load 900N),it glides at the speed of 3km/h,and the brake displacement shall be≤0.2m;for the type B hanging wheel,when it bears a person on the slope ofα=20°(total load 900N),it glides at the speed of 3km/h,and the brake displacement shall be≤0.3m.The test cycle is 1 year.