阅读说明：本技术 道路运输液体危险货物车辆人孔盖锁合装置的设计方法 (Design method of manhole cover locking device of road transportation liquid dangerous cargo vehicle ) 是由 高吟 孟令启 高洪 肖平 王磊 徐凌峰 张磊 周玄 姚垚 张菲菲 于 2020-12-18 设计创作，主要内容包括：本发明公开了一种道路运输液体危险货物车辆人孔盖锁合装置的设计方法,包括步骤：S1、确定锁合装置的结构为包括与人孔凸台转动连接的曲柄、与人孔盖和曲柄转动连接的连杆和位于人孔凸台外侧的操纵手柄,曲柄、连杆、人孔凸台和人孔盖构成曲柄滑块机构；S2、确定锁合装置须满足的极位锁止条件；S3、确定人孔盖能够打开须满足的条件；S4、确定人孔盖在打开后能够相对于连杆进行转动须满足的条件。本发明的道路运输液体危险货物车辆人孔盖锁合装置的设计方法,设置的锁合装置可以利用曲柄滑块机构的极位锁止特性,实现人孔盖的锁止固定,具有结构简单、锁止安全牢靠的优点,可以确保人孔盖盖合锁止安全牢靠。(The invention discloses a design method of a manhole cover locking device of a vehicle for transporting liquid dangerous goods on roads, which comprises the following steps: s1, determining that the locking device has a structure comprising a crank rotationally connected with the manhole boss, a connecting rod rotationally connected with the manhole cover and the crank, and an operating handle positioned on the outer side of the manhole boss, wherein the crank, the connecting rod, the manhole boss and the manhole cover form a crank sliding block mechanism; s2, determining the pole locking condition which needs to be met by the locking device; s3, determining conditions which need to be met when the manhole cover can be opened; and S4, determining the conditions which are required to be met when the manhole cover can rotate relative to the connecting rod after being opened. According to the design method of the manhole cover locking device of the vehicle for road transportation of the liquid dangerous goods, the arranged locking device can realize locking and fixing of the manhole cover by utilizing the extreme locking characteristic of the crank-slider mechanism, has the advantages of simple structure and safe and firm locking, and can ensure that the manhole cover is safely and firmly locked.)

1. The design method of the manhole cover locking device of the vehicle for road transportation of the liquid dangerous goods is characterized by comprising the following steps:

s1, determining the structure of the locking device as comprising a crank rotationally connected with the manhole boss, two connecting rods rotationally connected with the manhole cover and the crank and an operating handle positioned outside the manhole boss, wherein the two cranks and the two connecting rods are fixedly connected with the operating handle, and the crank, the connecting rods, the manhole boss and the manhole cover form a crank slider mechanism;

s2, determining the polar position locking condition that the locking device needs to meet according to the requirement that the crank slider mechanism is at the dead point position and the connecting rod and the crank are in the overlapping collinear state after the manhole cover is covered;

s3, determining conditions which need to be met when the manhole cover can be opened;

and S4, determining the conditions which are required to be met when the manhole cover can rotate relative to the connecting rod after being opened.

2. The method of claim 1, wherein one end of the connecting rod is rotatably connected to the manhole cover by a manhole cover pin, the other end of the connecting rod is rotatably connected to one end of the crank by a hinge pin, the other end of the crank is rotatably connected to the manhole boss by a crank pin, the manhole boss has a first threaded hole into which the crank pin is inserted, and the manhole cover has a second threaded hole into which the manhole cover pin is inserted.

3. The method for designing a manhole cover locking device of a road transportation vehicle for dangerous liquid cargo according to claim 2, wherein in step S2, the locking device has to satisfy the extreme locking conditions: h₂+H+H₁＝L₂-L₁Wherein H is₂The vertical distance between the axis of the first threaded hole on the manhole boss and the step surface in the accommodating hole, H is the depth of the accommodating hole, H₁The axis of the second threaded hole on the manhole cover and the manhole coverPerpendicular distance between the interfaces of (1), L₂Is the length of the connecting rod, L₁Is the length of the crank.

4. The method for designing a manhole cover locking device of a vehicle for road transportation of dangerous goods according to claim 3, wherein in step S3, the conditions to be satisfied when the manhole cover is opened are: h<2L₁。

5. The method for designing a manhole cover locking device of a vehicle for road transportation of dangerous goods as claimed in claim 4, wherein in step S4, it is determined that the conditions to be satisfied when the manhole cover can rotate relative to the connecting rod after being opened are: h'<H，L₁+L₂-(H₂+H)>R, H' is the height of the boss under the manhole cover, and R is the radius or semi-major axis length of the interface of the manhole cover.

6. The design method of manhole cover locking device of road transportation liquid dangerous cargo vehicle of any of claims 1 to 5, wherein the two connecting rods and the two cranks are symmetrically arranged.

7. The design method of manhole cover locking device of road transportation liquid dangerous cargo vehicle of any one of claims 1 to 6, wherein when the crank-slider mechanism is at the dead point position, the operating handle is tightly attached to the outer circumferential surface of the manhole boss.

Technical Field

The invention belongs to the technical field of special transport vehicles, and particularly relates to a design method of a manhole cover locking device of a vehicle for transporting liquid dangerous goods on roads.

Background

National standard GB 18564.1-2019 road transport liquid dangerous cargo tank vehicle part 1: in the technical requirements of the metal normal-pressure tank body, the liquid dangerous goods transported by the dangerous goods tank vehicle are defined as the liquid goods which have dangerous characteristics of explosion, flammability, toxicity, infection, corrosion, oxidation and the like, are easy to cause personal injury, property loss or environmental pollution and need to be specially protected in transportation, storage, production, operation, use and treatment. And the manhole cover of the road transportation liquid dangerous cargo tank vehicle is set for injecting liquid into the top and facilitating the working personnel to enter the tank body for working or overhauling, and meanwhile, the liquid in the tank is sealed, so that the leakage effect in the transportation process is prevented. The national standard GB 18564.1-2019 requires that the tank body is provided with at least one manhole, generally can be arranged at the top of the tank body, and each sub-bin is provided with at least one manhole; the manhole should be a round hole with a nominal diameter greater than or equal to 500mm or an elliptical hole with a nominal diameter of 500mm x 400 mm. The technical requirements and the test method for the manhole cover of the tank vehicle for transporting the flammable liquid dangerous goods by the QC/T1065-2017 road are strictly specified.

When the tank vehicle for the liquid dangerous goods transported on the road transports the liquid dangerous goods, the canned liquid dangerous goods are continuously vibrated due to the effects of inertia force of acceleration and deceleration driving, centrifugal force during sharp turning and the like, the manhole cover is required to be safe and firm after being closed in order to prevent the transported liquid dangerous goods from leaking from the cover opening, and the tank vehicle is convenient, flexible and free of clamping stagnation during opening the cover, and the requirements cannot be met by the prior art.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a design method of a manhole cover locking device of a vehicle for transporting liquid dangerous goods on the road, and aims to ensure that the locking of the cover of the manhole cover is safe and firm.

In order to achieve the purpose, the invention adopts the technical scheme that: the design method of the manhole cover locking device of the road transportation liquid dangerous cargo vehicle comprises the following steps:

s1, determining the structure of the locking device as comprising a crank rotationally connected with the manhole boss, two connecting rods rotationally connected with the manhole cover and the crank and an operating handle positioned outside the manhole boss, wherein the two cranks and the two connecting rods are fixedly connected with the operating handle, and the crank, the connecting rods, the manhole boss and the manhole cover form a crank slider mechanism;

s2, determining the polar position locking condition that the locking device needs to meet according to the requirement that the crank slider mechanism is at the dead point position and the connecting rod and the crank are in the overlapping collinear state after the manhole cover is covered;

s3, determining conditions which need to be met when the manhole cover can be opened;

and S4, determining the conditions which are required to be met when the manhole cover can rotate relative to the connecting rod after being opened.

One end of the connecting rod is rotatably connected with the manhole cover through a manhole cover pin shaft, the other end of the connecting rod is rotatably connected with one end of the crank through a hinge pin shaft, the other end of the crank is rotatably connected with a manhole boss through a crank pin shaft, the manhole boss is provided with a first threaded hole for the crank pin shaft to insert, and the manhole cover is provided with a second threaded hole for the manhole cover pin shaft to insert.

In step S2, the pole locking condition that the locking device must satisfy is: h₂+H+H₁＝L₂-L₁Wherein H is₂The vertical distance between the axis of the first threaded hole on the manhole boss and the step surface in the accommodating hole, H is the depth of the accommodating hole, H₁Is the vertical distance, L, between the axis of the second threaded hole in the manhole cover and the interface on the manhole cover₂Is the length of the connecting rod, L₁Is the length of the crank.

In step S3, the conditions to be satisfied when the manhole cover is opened are determined as follows: h<2L₁。

In step S4, the conditions that the manhole cover can rotate with respect to the link after being opened are determined as follows: h'<H，L₁+L₂-(H₂+H)>R, H' is the height of the boss under the manhole cover, and R is the radius or semi-major axis length of the interface of the manhole cover.

The two connecting rods and the two cranks are symmetrically arranged.

When the crank slider mechanism is positioned at a dead point position, the operating handle is tightly attached to the outer circular surface of the manhole boss.

According to the design method of the manhole cover locking device of the vehicle for road transportation of the liquid dangerous goods, the arranged locking device can realize locking and fixing of the manhole cover by utilizing the extreme locking characteristic of the crank-slider mechanism, has the advantages of simple structure and safe and firm locking, and can ensure that the manhole cover is safely and firmly locked.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a schematic view of a cylindrical manhole boss;

FIG. 2 is a schematic view of an elliptical cylindrical manhole boss;

FIG. 3 is a schematic view of a cylindrical manhole cover;

FIG. 4 is a schematic view of an elliptical cylindrical manhole cover;

FIG. 5 is a crank pin schematic;

FIG. 6 is a schematic view of the crank;

FIG. 7 is a schematic view of a connecting rod;

FIG. 8 is a schematic view of a circular joystick;

FIG. 9 is a schematic view of an elliptical joystick;

FIG. 10 is a schematic view of a manhole cover pin;

FIG. 11 is a schematic view of the polar locking device in an uncapped state with the manhole boss being cylindrical;

FIG. 12 is a schematic view of the closed state of the polar locking device when the manhole boss is cylindrical;

FIG. 13 is a schematic view of the polar locking device in an uncapped state when the manhole boss is in an elliptic cylinder shape;

FIG. 14 is a schematic view of the closed state of the polar locking device when the manhole boss is an elliptic cylinder;

FIG. 15 is a flow chart of the design method of the manhole cover locking device of the road transportation liquid dangerous cargo vehicle of the invention;

labeled as: 1. a manhole boss; 101. an outer circular surface; 101A, a cylindrical counter bore; 101B, a first threaded hole; 101C, step surface; 102. an outer circular surface; 102A, an elliptic cylindrical counter bore; 102B, a first threaded hole; 102C, step surfaces; 2. a manhole cover; 201. a cylindrical manhole cover; 201B, a lower boss; 201D, an upper boss; 201A, a second threaded hole; 201C, interface; 202. an elliptical cylindrical manhole cover; 202B, a lower boss; 202D, an upper boss; 202A and a second threaded hole; 202C, interface; 3. a crank pin shaft; 3A, a threaded rod; 3B, cylindrical bosses; 3C, a crank pin shaft 3; 3D, axially positioning a clamp spring groove by a crank; 4. a crank; 4A, a crank pin hole; 4B, connecting rod pin holes; 4C, a boss; 5. a connecting rod; 5B, a hinge hole of the manhole cover; 5A, a crank hinge hole; 5E, a motion plane; 5C, rectangular positioning grooves; 5D, a threaded hole; 5F, a side surface; 6. a control handle; 601. a circular operating handle; 601C, a semicircular structure; 601D, a semicircular handle; 601A, positioning holes; 601B, an upper plane; 602. an elliptical manipulating handle; 602C, a semi-elliptical arc structure; 602D, a semicircular gripper; 602A, positioning holes; 602B, an upper plane; 7. a manhole cover pin shaft; 7A, a threaded shaft; 7D, a cylindrical boss; 7B, a hinge shaft; 7C, positioning a clamp spring groove.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings for a purpose of helping those skilled in the art to more fully, accurately and deeply understand the concept and technical solution of the present invention and to facilitate its implementation.

As shown in fig. 11 to 15, the present invention provides a design method of a manhole cover locking device of a vehicle for road transportation of liquid dangerous goods, comprising the following steps:

s1, determining the structure of the locking device as comprising a crank 4 rotationally connected with a manhole boss 1, a connecting rod 5 rotationally connected with the manhole cover 2 and the crank 4 and an operating handle 6 positioned on the outer side of the manhole boss 1, wherein the two cranks 4 and the two connecting rods 5 are arranged, the operating handle 6 is connected with the two connecting rods 5, and the crank 4, the connecting rod 5, the manhole boss 1 and the manhole cover 2 form a crank slider mechanism;

s2, determining the polar position locking condition that the locking device needs to meet according to the requirement that the crank slide block mechanism is at the dead point position and the connecting rod 5 and the crank 4 are in the overlapping collinear state after the manhole cover 2 is covered;

s3, determining the conditions to be met when the manhole cover 2 can be opened;

s4, determining a condition to be satisfied when the manhole cover 2 can be rotated with respect to the link 5 after being opened.

Specifically, as shown in fig. 11 to 14, in the step S1, two links 5 and two cranks 4 are symmetrically arranged, the manhole cover 2 and the manhole boss 1 are coaxially disposed, the manhole cover 2 is located between the two links 5, the manhole boss 1 is located between the two cranks 4, an included angle between the two links 5 is 180 degrees, accordingly, an included angle between the two cranks 4 is also 180 degrees, one manipulating handle 6 is provided, the manipulating handle 6 is fixedly connected to the two links 5, and the manipulating handle 6 is used for being held by a hand of an operator. Two sets of completely symmetrical slider-crank mechanisms (wherein the manhole cover 2 is equivalent to a slider moving along a counter bore in the manhole boss) are arranged at two sides of the manhole boss 1. The operating handle 6 is fixedly connected with the two connecting rods 5 at the two sides, so that the linkage of the two groups of symmetrical crank sliding block mechanisms is realized. When the crank slider mechanism is at the dead point position, the operating handle 6 is tightly attached to the outer circular surface of the manhole boss 1.

Moreover, the two connecting rods 5 at two sides are fixedly connected by the operating handle 6, so that the operating handle 6 becomes a manual operation force application component for locking and unlocking the crank slider mechanisms (namely, the locking device for the manhole cover polar position of the road transportation liquid dangerous cargo tank vehicle) symmetrically arranged at two sides of the manhole boss 1, and the manual operation force application component is lighter and more labor-saving compared with the way that the force application component is arranged on the crank 4.

As shown in fig. 11 to 14, one end of the connecting rod 5 is rotatably connected to the manhole cover 2 through a manhole cover pin 7, the other end of the connecting rod 5 is rotatably connected to one end of the crank 4 through a hinge pin, and the other end of the crank 4 is rotatably connected to the manhole boss 1 through a crank pin 3. The axis of the manhole cover pin shaft 7 is vertical to the axis of the manhole cover 2, the axis of the crank pin shaft 3 is vertical to the axis of the manhole boss 1, and the axis of the crank pin shaft 3 is parallel to the axis of the manhole cover pin shaft 7. One end of the connecting rod 5 is provided with a manhole cover hinge hole through which the manhole cover pin shaft 7 penetrates, the other end of the connecting rod 5 is provided with a crank hinge hole through which the hinge pin shaft penetrates, one end of the crank 4 is provided with a connecting rod pin hole through which the hinge pin shaft penetrates, and the other end of the crank 4 is provided with a crank pin hole through which the crank pin shaft 3 penetrates.

As shown in fig. 1 and 3, the manhole cover 2 includes an upper boss and a lower boss connected to a bottom surface of the upper boss, the lower boss has a diameter smaller than that of the upper boss, and the upper boss and the lower boss are coaxially disposed. Manhole boss 1 has the hole of dodging and lets the holding hole of boss embedding down, dodges the hole and holds the hole and be coaxial setting, dodges the hole and is located the below of holding the hole and the diameter of dodging the hole and is less than the diameter of holding the hole, holds the counter bore that the hole formed for starting to extend downwards towards the inside of manhole boss 1 from the top surface of manhole boss 1, dodges the through-hole that the hole formed for starting to extend downwards towards the bottom surface of manhole boss 1 from holding the hole bottom.

The sealing part of the tank body of the vehicle is a manhole boss 1, and the tank body can have two different cross-sectional shapes of a circle and an ellipse according to the requirements of GB 18564.1-2019.

As shown in fig. 1, the manhole boss 1 is a cylindrical structure, the cross section of the manhole boss 1 is a circle with a radius of 500mm, the outer circular surface 101 of the manhole boss 1 is a cylindrical surface, the accommodating hole and the avoiding hole are circular holes, the accommodating hole is a cylindrical counter bore 101A, and the depth of the accommodating hole is H mm (H: (a) (b))A step surface 101C is formed between the accommodating hole and the avoiding hole, the depth of the accommodating hole is the vertical distance between the top surface of the manhole boss 1 and the step surface 101C, the top surface of the manhole boss 1 and the step surface 101C are parallel planes, and the wall thickness is delta mm (selected according to the national standard GB 18564.1-2019 according to the difference that the tank body materials are steel, aluminum and aluminum alloy). Two first threaded holes 101B are formed in the outer circular surface 101 of the manhole boss 1, the first threaded holes 101B are used for allowing the crank pin shaft 3 to be inserted, the axis of each first threaded hole 101B is perpendicular to the axis of the manhole boss 1, the two first threaded holes 101B are coaxially arranged, and the perpendicular distance between the axis of each first threaded hole 101B and the step surface 101C of the accommodating hole is H₂。

As shown in fig. 2, the manhole boss 1 has an elliptical structure, the cross section of the manhole boss 1 has a long axis and a short axis respectively equal to 500mm and 400mm, the cross section of the outer circular surface 101 of the manhole boss 1 has an elliptical shape, and the accommodating hole and the avoiding hole are elliptical holes. The containing hole is an elliptic cylindrical counter bore 102A, the depth of the containing hole is H mm (a step surface 102C is formed between the containing hole and the avoiding hole, the depth of the containing hole is the vertical distance between the top surface of the manhole boss 1 and the step surface 102C, the top surface of the manhole boss 1 and the step surface 102C are parallel planes), and the wall thickness is delta mm (the wall thickness can be selected according to the national standard GB 18564.1-2019 according to the difference of steel, aluminum and aluminum alloy which are used as tank body materials). Two first threaded holes 102B are formed in the outer circular surface 102 of the manhole boss 1, the axis of each first threaded hole 102B is perpendicular to the axis of the manhole boss 1, the two first threaded holes 102B are coaxially arranged, the axis of each first threaded hole 102B is a short axis with an oval cross section, each first threaded hole 102B is used for allowing the crank pin shaft 3 to be inserted, and the perpendicular distance between the axis of each first threaded hole 102B and the step surface 101C of the containing hole is H₂。

In order to match the manhole boss 1, the manhole cover 2 is also divided into two different cross-sectional shapes, circular and elliptical (see GB 18564.1-2019).

As shown in fig. 1 and 3, the manhole boss 1 is a cylindrical structure, the accommodating hole and the avoiding hole are circular holes, the lower boss 201B is circular, the upper boss 201D is cylindrical, the diameter of the lower boss 201B is the same as that of the accommodating hole, and the upper boss 201D and the lower boss 201B are connected with each otherAn interface 201C is arranged between the lower bosses 201B, the interface 201C is a plane perpendicular to the axes of the upper bosses and the lower bosses, and after the manhole cover 2 is fixed on the manhole boss 1, the interface 201C is attached to the top surface of the manhole boss 1, namely the bottom surface of the upper boss. The outer diameter of the lower boss 201B is smaller than that of the upper boss, the excircle radius of the lower boss 201B is (500-delta) mm, and the height of the lower boss 201B is H' mm; two second threaded holes 201A are formed in the cross section, perpendicular to the axis, of the outer circular surface of the upper boss 201D, the axes of the two second threaded holes 201A coincide with the diameter of the cross section circle, the two second threaded holes 201A are coaxially arranged, the second threaded holes 201A are used for allowing the manhole cover pin shaft 7 to be inserted, and the perpendicular distance between the axis of the second threaded holes 201A and the interface 201C is H₁。

As shown in fig. 2 and 4, the manhole boss 1 has an elliptical structure, the accommodating hole and the avoiding hole are elliptical holes, the lower boss 202B has an elliptical ring shape, the cross section of the upper boss 202D has an elliptical shape, the lengths of the long axis and the short axis of the lower boss 201B are the same as the lengths of the long axis and the short axis of the accommodating hole, respectively, an interface 202C is provided between the upper boss 202D and the lower boss 202B, the interface 202C is a plane perpendicular to the axes of the upper boss and the lower boss, and after the manhole cover 2 is fixed on the manhole boss 1, the interface 202C is attached to the top surface of the manhole boss 1. The section of the lower boss 202B is an ellipse with the major and minor axes respectively equal to (500-delta) mm and (400-delta) mm, and the height of the lower boss 202B is H' mm; two second threaded holes 202A are formed in the cross section, perpendicular to the axis of the elliptic cylinder, of the outer circular surface of the upper boss 202D, the axis of each second threaded hole 202A is a short axis of the elliptic cross section, the two second threaded holes 202A are coaxially arranged, the second threaded holes 202A are used for allowing the manhole cover pin shaft 7 to be inserted, and the perpendicular distance between the axis of each second threaded hole 202A and the interface 202C is H₁。

As shown in fig. 5, the crank pin 3 includes a threaded rod 3A, a cylindrical boss 3B which is coaxially and fixedly connected with the threaded rod 3A, and a first pin body 3C which is coaxially and fixedly connected with the cylindrical boss 3B, a first clamp spring groove 3D is provided on the first pin body 3C, and the first clamp spring groove 3D is a circular groove extending along the whole circumferential direction on the outer circumferential surface of the first pin body 3C. The cylindrical boss 3B is positioned between the threaded rod 3A and the first pin shaft body 3C, and the diameter of the cylindrical boss 3B is larger than that of the threaded rod 3A and the first pin shaft body 3C. The threaded rod 3A is provided with an external thread, the threaded rod 3A is inserted into a first threaded hole 101B or 102B in the manhole boss 1, and the threaded rod 3A is in threaded connection with the manhole boss 1. During assembly, the threaded rods 3A of the two crank pin shafts 3 are screwed into the two first threaded holes 101B or 102B of the manhole boss 1, and the first pin shaft body 3C penetrates through a crank pin hole in the crank 4.

As shown in fig. 6, the crank 4 has a rod-like structure with a rectangular cross section, and one end of the crank 4 is provided with a crank pin hole 4A and the other end of the crank 4 is provided with a connecting rod pin hole 4B. The crank 4 is provided with a boss 4C, the boss 4C and the connecting rod pin hole 4B are located at the same end of the crank 4, the boss 4C extends out towards one side of the crank 4, the boss 4C is used for compensating a gap between the motion planes of the crank 4 and the connecting rod 5 during assembly, the connecting rod 5 is ensured to be compactly assembled on the outer side of the crank 4, the boss 4C is located between the crank 4 and the connecting rod 5, the connecting rod pin hole 4B penetrates through the boss 4C, and the crank 4 is located between the connecting rod 5 and the manhole boss 1. During assembly, a crank pin hole 4A of the crank 4 is arranged in a first pin shaft body 3C of the crank pin shaft 3, and a clamp spring (not shown in the figure) is arranged in a first clamp spring groove 3D on the outer end face of the crank 4, so that the crank 4 is axially fixed relative to the crank pin shaft 3.

As shown in fig. 7, the length of the connecting rod 5 is greater than that of the crank 4, the connecting rod 5 is a rod-shaped structure, the cross section of the connecting rod is rectangular, one end of the connecting rod 5 is provided with a manhole cover hinge hole 5B, the other end of the connecting rod 5 is provided with a crank hinge hole 5A, and the middle of the motion plane 5E of the connecting rod 5 is provided with a rectangular positioning slot 5C and a threaded hole 5D. The outer surface of the link 5 comprises a plane of movement 5E and a side 5F, the plane of movement 5E and the side 5F being perpendicular to each other. The end of the operating handle 6 is embedded into the rectangular positioning groove 5C of the connecting rod 5, the two ends of the operating handle 6 are fixedly connected with the two connecting rods 5 through screws, and the screws are screwed into the threaded holes 5D.

The operating handle 6 has two different structures according to the manhole boss 1, and also has two different structural forms.

As shown in fig. 1 and 8, the manhole boss 1 is a cylindrical structure, the outer circumferential surface of the manhole boss 1 is a cylindrical surface, the operating handle 6 is a semicircular ring and is an axisymmetric structure, the main body portion of the operating handle 6 is a semicircular structure 601C, the radius of the semicircular structure 601C is slightly larger than the radius of the outer circumferential surface 101 of the manhole boss 1, and the radius of the semicircular structure 601C is 500+3 mm; the middle position in the arc length direction of the semicircular structure 601C is provided with a hand grip 601D with the diameter of 8cm, the hand grip 601D is used for holding by the hand of an operator, and the positions close to the two ends of the semicircular structure 601C are respectively provided with a positioning hole 601A matched with the rectangular positioning groove 5C and the circular threaded hole 5D. When the operating handle 6 is assembled with the connecting rod 5, the inner sides of the two ends of the operating handle 6 are inserted into the rectangular positioning groove 5C formed in the middle of the moving plane 5E of the connecting rod 5, the positioning hole 601A is aligned with the threaded hole 5D, and then the fastening screw (not shown) is installed, so that the operating handle 6 and the connecting rod 5 are fixedly connected. Through the matching arrangement of the rectangular positioning groove 5C and the threaded hole 5D with the positioning hole 601A, the operating handle 6 can be prevented from loosening due to relative movement between the operating handle 6 and the connecting rod 5 in the operating process, and the upper plane 601B of the operating handle 6 can be ensured to be vertical to the movement plane 5E of the connecting rod 5 and the side surface 5F of the connecting rod 5 at the same time, so that the operating handle 6 can be ensured to be tightly attached to the outer circular surface of the manhole boss after the manhole cover is covered. The upper plane 601B of the bar handle 6 is a plane perpendicular to the axis of the bar handle 6.

As shown in fig. 2 and 9, the manhole boss 1 has an elliptical structure, the cross section of the outer circumferential surface of the manhole boss 1 has an elliptical shape, and the operating handle 6 has a semi-elliptical ring shape and an axisymmetric structure. The main body part of the operating handle 6 is a semi-elliptical arc structure 602C, and the long and short axes of the semi-elliptical arc structure 602C are respectively equal to 500+3mm and 400+3mm (a semi-elliptical arc is reserved by taking the short axis as a symmetry axis); a circular hand grip 602D with the diameter of 8cm is arranged in the middle of the semi-elliptical arc 602C, the hand grip 602D is used for being held by the hand of an operator, and positioning holes 602A matched with the rectangular positioning groove 5C and the circular threaded hole 5D are respectively arranged at positions close to the two ends of the semi-elliptical arc 602C. When the semi-elliptical operating handle 6 is assembled with the connecting rod 5, the inner sides of the two ends of the operating handle 6 are inserted into the rectangular positioning groove 5C formed in the middle of the movement plane 5E of the connecting rod 5, the positioning hole 602A is aligned with the circular threaded hole 5D, and then the fastening screw (not shown in the figure) is installed, so that the operating handle 6 and the connecting rod 5 are fixedly connected. Through the matching arrangement of the rectangular positioning groove 5C and the circular threaded hole 5D with the positioning hole 602A, the operating handle 6 can be prevented from loosening due to relative movement with the connecting rod 5 in the operating process, and the upper plane 602B of the operating handle 6 can be ensured to be perpendicular to the moving plane 5E and the side surface 5F of the connecting rod 5 at the same time, so that the operating handle 6 can be ensured to be tightly attached to the outer circular surface of the manhole boss 1 after the manhole cover 2 is covered.

As shown in fig. 10, the manhole cover pin 7 includes a threaded shaft 7A, a cylindrical boss 7D coaxially and fixedly connected to the threaded shaft 7A, and a second pin body 7B coaxially and fixedly connected to the cylindrical boss 7D, the second pin body 7B is provided with a second clamp spring groove 7C, and the second clamp spring groove 7C is a circular groove extending along the entire circumferential direction on the outer circumferential surface of the second pin body 7B. The cylindrical boss 7D is located between the threaded shaft 7A and the second pin shaft body 7B and the diameter of the cylindrical boss 7D is larger than the diameter of the threaded shaft 7A and the second pin shaft body 7B. The threaded shaft 7A is provided with an external thread, the threaded shaft 7A is inserted into a second threaded hole 201A or 202A on the manhole boss 1, and the threaded shaft 7A is in threaded connection with the manhole boss 1. During assembly, the threaded shafts 7A of the two manhole cover pin shafts 7 are screwed into the two second threaded holes 201A or 202A of the manhole cover 2, so that the manhole cover pin shafts 7 are fixedly connected with the manhole cover 2. When the connecting rod 5 is assembled, the second pin shaft body 7B penetrates through a manhole cover hinge hole in the connecting rod 5, and then the clamp spring is installed in the second clamp spring groove 7C, so that the connecting rod 5 is axially fixed relative to the manhole cover pin shaft 7; after the centers of the crank hinge hole 5A and the connecting rod pin hole 4B on the crank 4 are aligned, the hinge pin shaft is arranged and axially positioned.

Two cranks 4 are respectively arranged at the inner sides of the two connecting rods 5. As shown in fig. 11 to 14, when assembling, the crank 4 is installed on the manhole boss 1, and the crank 4 is rotated relative to the manhole boss 1; connecting the crank 4 and the connecting rod 5 by a hinge pin shaft; then the connecting rod 5 is connected with the manhole cover 2 through a manhole cover pin shaft 7, and the connecting rod 5 and the manhole cover 2 can rotate relatively; finally, the operating handle 6 is fixedly connected to the two connecting rods 5.

As shown in fig. 12 and 14, the closing process of the manhole cover 2 is as follows: the operator presses the manhole cover 2 into the manhole boss 1 with one hand, so that the lower boss falls into the containing hole (the lower boss 201B falls into the cylindrical counter bore 101A or the lower boss 202B falls into the elliptical cylindrical counter bore 102A); the other hand of the operator holds the grip of the operating handle and presses the operating handle 6 downwards until the inner circular surface of the operating handle 6 is attached to the outer circular surface of the manhole boss 1, at the moment, the connecting rod 5 and the crank 4 are respectively in the overlapped collinear position, the position of the manhole cover 2 is fixed, and the crank slider mechanism is in the dead point position, so that the manhole cover 2 cannot be opened even if a large force is acted on the manhole cover 2. When the cover is opened, the hand grip on the control handle 6 is pulled upwards by one hand, so that the manhole cover 2 can be separated from the manhole boss 1. During the opening and closing process of the manhole cover 2, the operating handle 6 can only move at one side of the manhole boss 1, so that the rotation angle range of the crank 4 is controlled within the range of 0-180 degrees.

The structural size of the locking device meets the requirements of distance between the axes of the two threaded holes on the manhole boss and the lower end surface of the counter bore in the manhole boss and the depth of the counter bore in the manhole boss, and the sum of the distances from the axes of the two threaded holes on the manhole cover 2 to the interface of the upper and lower bosses thereof is equal to the length difference between the connecting rod 5 and the crank 4, when downward pressure is applied to the operating handle 6, the operating handle 6 can be tightly attached to the outer circular surface of the manhole boss, the crank-slider mechanism (i.e. the manhole cover polar locking device of the road transportation liquid dangerous cargo tank vehicle) is in the locking position, the connecting rod 5 and the crank 4 are in the overlapped collinear position, when the external force on the operating handle 6 is removed, the crank-slider mechanism is positioned at a dead point position, the locking is very firm, and the unlocking can be realized only by applying an external couple moment on the connecting rod 5 or the crank 4.

In step S2, the center distance L between the crank pin hole 4A and the link pin hole 4B of the crank 4 is set₁(ii) a The center distance between a manhole cover hinge hole 5B on the connecting rod 5 and a crank hinge hole 5A is L₂。

In step S2, according to the dead point locking principle of the slider-crank mechanism, in order to ensure that the locking device can achieve secure and reliable locking of the manhole cover, the polar position locking conditions that need to be satisfied are: vertical distance H between axis of first threaded hole on manhole boss 1 and step surface in accommodating hole₂Depth H of the receiving hole, and second threaded hole axis and manhole on the manhole cover 2Vertical distance H between the dividing surfaces on the cover 2₁Must be equal to the length L of the connecting rod 5₂Length L of crank 4₁I.e.:

H₂+H+H₁＝L₂-L₁ (1)

in the above step S3, in order to ensure that the lower boss of the manhole cover 2 can smoothly leave the receiving hole of the manhole boss 1 when the operating handle 6 moves upward, the following conditions should be satisfied:

H<2L₁ (2)

in step S4, in order to ensure that the manhole cover 2 can rotate freely with respect to the tie rod 5 and does not interfere with the upper edge of the manhole boss 1 after the manhole cover 2 is opened, the following conditions must be satisfied:

H′<H (3)

L₁+L₂-(H₂+H)>R (4)

in the above formula, H₂Is the vertical distance between the axis of the first threaded hole on the manhole boss 1 and the step surface in the accommodating hole, H is the depth of the accommodating hole, H₁Is the vertical distance, L, between the axis of the second threaded hole in the manhole cover 2 and the interface in the manhole cover 2₂Is the length, L, of the connecting rod 5₁Is the length of the crank 4 and H' is the height of the boss under the manhole cover. Wherein, the value of R in the formula (4) is that R is the radius of the bottom surface of the upper boss 201D (namely the radius of the circular interface) of the cylindrical manhole cover 201; for an oval cylindrical manhole cover 202, R is the length of the semimajor axis of the bottom ellipse of the upper boss 202D (i.e., the length of the semimajor axis of the oval interface).

The invention is described above with reference to the accompanying drawings. It is to be understood that the specific implementations of the invention are not limited in this respect. Various insubstantial improvements are made by adopting the method conception and the technical scheme of the invention; the present invention is not limited to the above embodiments, and can be modified in various ways.