This standard specifies the technical requirements, test and inspection rules for ground loading cranes. JB/T 7688.3-1995 Technical conditions for metallurgical cranes Ground loading cranes JB/T7688.3-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Metallurgical Cranes
Ground Loading Cranes
1 Subject Content and Scope of Application
This standard specifies the technical requirements, test and inspection rules, etc. for ground loading cranes. JB/T 7688.3-95wwW.bzxz.Net
This standard applies to ground loading cranes (hereinafter referred to as cranes) that use a material box pick-up rod as a picking device to load open-hearth furnaces. 2 Reference Standards
GB3766 General Technical Conditions for Hydraulic Systems
JB/T7688.1 Technical Conditions for Metallurgical Cranes General Requirements JB/T7688.2 Technical Conditions for Metallurgical Cranes Open-hearth Loading Bridge Cranes JB11365 Accuracy of Bevel Gears and Hypoid Gears 3 Technical Requirements
Except for the following requirements, other technical requirements shall comply with the relevant provisions in JB/T7688.1. 3.1 Environmental conditions
The minimum working environment temperature of the crane is -10°C and the maximum is not more than 105°C. 3.2 Performance
The rated lifting capacity of the crane is the sum of the mass of the material box and the material being lifted. 3.3 Main components
3.3.1 The material of the crankshaft and connecting rod of the lifting lever swing mechanism shall not be lower than 45 steel in GB699. The limit deviation of the dimension of the upper and lower axis distance of the crankshaft is ±1 mm.
3.3.2 The material of the lifting lever shall comply with the provisions of Article 3.4.2 of JB/T7688.2. 3.3.3 The material of the front and rear wheel axles of the trolley and the car shall not be lower than 45 steel in GB699. 3.3.4 The wheels are recommended to be forged wheels made of 65Mn steel. The tread hardness is 300~380HBS. The depth of the hardened layer is not less than 20mm and the hardness at the depth is not less than 260HBS. The tolerance of the wheel tread diameter is h9. 3.3.5 The material of the upper and lower guide springs of the trolley shall not be less than 45 steel, and the tread hardness shall not be less than 40HRC. The depth of the hardened layer is 2~~4mm. The tolerance of the roller diameter is h9. 3.3.6 The precision of the bevel gear pair used in the reducer shall not be less than grade 8 in GB11365, and the precision of the open bevel gear pair shall not be less than grade 9.
3.3.7 The height difference of each group of springs in the swing mechanism buffer device shall not be greater than 3mm. 3.3.8 Bridge
3.3.8.1 The camber of the main beam mid-span is (0~1/2000)S. 3.3.8.2 The diagonal difference of the bridge shall not be greater than 4mm. 3.3.8.3 The upper wheel gauge K and the lower wheel gauge K of the trolley. The limit deviation shall not exceed 2mm (see Figure 1). 3.3.8.4 The height difference between the two tracks on the same section perpendicular to the running direction of the trolley shall not exceed 2mm (see Figure 1). Approved by the Ministry of Machinery Industry of the People's Republic of China on June 16, 1995 and implemented on July 1, 1996
JB/T 7688.3-95
3.3.8.5 The limit deviation of the distance A between the upper wheel track surface and the lower wheel track surface of the trolley is 0.5mm, and the limit deviation of the distance B between the lower wheel track surface is ±1mm (see Figure 1).
3.3.8.6 The limit deviation of the trolley stop C is ±2mm (see Figure 1). 3.3.8.7 It is recommended that the lifting rod locking mechanism adopts hydraulic drive, and its hydraulic components should meet the requirements of GB3766. 3.4 Assembly
3.4.1 The gap between the lower wheel of the trolley and its track surface is 2~~4mm. 3.4.2 The clearance between the trolley frame and the car block on each side is 4~5mm. 3.4.3 After the sections of the boom are connected, the requirements for the connection surface shall comply with Article 3.5.10 of JB/T7688.2. 3.4.4 Each set of springs in the buffer device of the boom swing mechanism shall be pre-tightened and leveled, and the height difference shall not exceed 4mm. After installation, the pull rod bolts must be tightened and must not be loosened.
3.4.5 Adjust the spring and stroke of the hydraulic pusher or other lock box mechanism in the boom locking mechanism to make the lock box accurate and reliable. 3.4.6 The maximum deviation of the span of the crane is ±4mm. 3.4.7 The maximum deviation of the track gauge K measured by the trolley wheels shall not exceed ±2mm. 3.4.8 For the assembled unloaded trolley, the driving wheel shall be in contact with the supporting rail surface, and the gap between the passive wheel tread and the rail surface shall not be greater than 0.3 mm.
3.4.9 The clearance between the upper and lower guide spring rollers of the trolley and the two side car block slideways should be 1 to 2 mm. 3.5 Electrical equipment
The power supply collector frame of the crane should have good rigidity, and the collector should be in uniform contact with the power supply slide line. 3.6 Safety and hygiene
3.6.1 The driver's cab should have a good field of vision, and its horizontal field of vision angle should not be less than 280°. 3.6.2 It is recommended to install a trolley operation limiter. 3.6.3 The trolley should be equipped with a handwheel device that can move the trolley to prevent the material box from being withdrawn from the furnace in the event of a sudden power outage. 3.6.4 Other requirements shall be in accordance with the relevant provisions of Articles 3.9.1, 3.9.5, 3.9.8, 3.9.9, 3.9.11, 3.9.133.9.20 and 3.9.25 of JB/T7688.1.
3.7 Lubrication
The crane should adopt point lubrication. Others shall be in accordance with Article 3.11 of JB/T7688.1. 564
4 Test
4.1 Visual inspection
JB/T 7688.3—95
The visual inspection of the crane shall be in accordance with the relevant provisions of Article 4.1 of JB/T7688.1. 4.2 Qualification test
It is recommended to adopt the method of gradual loading during the test, and it is allowed to load to the rated lifting weight at one time. Perform action tests in all directions at standard voltage and rated speed of the motor. In addition to verifying the contents specified in Article 4.2 of JB/T7688.1, the items listed in Table 1 should also be included.
Project name
Working speed
Lifting rod rotation speed
Lifting rod swing frequency
Handwheel device for moving trolley when power is off
Material box locking mechanism
Material box locking indicator device
4.3 Load-bearing capacity test
4.3.1 Static load test
Measurement unit
Times/min
Required value
As specified in the design drawings
Can be moved flexibly and conveniently Trolley
Flexible and reliable
Flexible and reliable
In addition to the relevant requirements of Article 4.3.1 of JB/T7688.1, the static load test of the crane shall also meet the following requirements: Limit deviation
Park the empty trolley (wheelbase center) in the center of the span, and the boom is perpendicular to the direction of travel of the trolley to determine the base point; a.
During the test, the trolley is moved to the middle of the span and loaded at 1.25G, based on the amount added to the material box. After unloading, check whether there is permanent deformation at the base point of the main beam in the middle of the span.
4.3.2 Dynamic load test
In addition to the relevant requirements of Article 4.3.2 of JB/T7688.1, the dynamic load test of the crane shall also meet the following requirements: a.
During the test, load 1.1G, which is added to the material box; the swing, rotation and locking mechanism of the material box lifting rod shall be tested repeatedly for 5 times; b.
During the test, each mechanism is required to operate smoothly and meet the functional requirements of each mechanism. When the lifting rod rotation is linked with the trolley running mechanism, no jamming is allowed.
5 Inspection rules
According to Chapter 5 of JB/T7688.1.
6 Marking, packaging, transportation and storage
According to Chapter 6 of JB/T7688.1.
Warranty period
According to Chapter 7 of JB/T7688.1.
Additional Notes;
This standard was proposed and managed by the Beijing Hoisting and Conveying Machinery Research Institute of the Ministry of Machinery Industry. This standard was drafted by Taiyuan Heavy Machinery Plant, and Beijing Hoisting and Conveying Machinery Research Institute participated in the drafting. The main drafter of this standard was Zhao Yonghua.
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