Magnetic type well lid opening device

Abstract

The utility model relates to the technical field of magnetic type well lid opening device, concretely relates to a magnetic type well lid opening device. Including lever, support axle, magnetic attraction subassembly, guide cylinder and moving rod. Support axle is located in the middle part of lever and is used as fulcrum. The guide cylinder is fixed to one end of the lever, the moving rod is arranged in the guide cylinder and can move along the axial direction, and the axial floating structure is formed. The lower end of the moving rod is hinged with the magnetic attraction subassembly through the pin shaft, the pin shaft is provided with the boss, the moving rod is provided with the limit slot, the boss extends into the limit slot and can slide in it, the maximum pitch angle of the magnetic attraction subassembly is limited through the slot end wall, and the angle limit structure is formed. The axial floating structure absorbs the transverse displacement caused by the rotation of the lever, and reduces the transverse shear force transmitted to the adsorption interface; the angle limit structure restricts the posture of the magnetic attraction subassembly, and prevents excessive overturning. The two synergies effectively inhibit the transverse sliding trend of the magnetic attraction subassembly on the well lid surface, and improve the adsorption stability and operation safety.

Description

Technical Field

[0001] This utility model relates to the technical field of magnetic manhole cover opening devices, specifically to a magnetic manhole cover opening device. Background Technology

[0002] Magnetic manhole cover opening devices are a common tool in municipal operations. A typical structure involves directly hinged the magnetic component to the end of a lever via a pin. This hinged structure provides the magnetic component with pitch freedom, allowing it to initially adapt to the manhole cover surface.

[0003] However, this structure has significant drawbacks in actual prying of manhole covers: because the lever end inevitably moves along an arc trajectory, while the magnetic component adheres to the essentially fixed manhole cover, the lack of coordination between their movements easily leads to slippage of the magnetic component on the manhole cover surface. This slippage is particularly pronounced under greater force or on uneven manhole cover surfaces, and may even cause the magnetic component to detach completely from the cover, posing a safety risk. Existing structures lack effective mechanisms to suppress this slippage problem. Utility Model Content

[0004] The purpose of this invention is to provide a magnetic manhole cover opening device to solve the problem that the magnetic components in the prior art are prone to slipping or even detaching from the manhole cover surface during prying operations, thereby improving the reliability and safety of the operation.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] The device includes a lever, a support shaft, and a magnetic traction assembly. The support shaft is located in the middle of the lever and is used to support the wellhead edge as a prying fulcrum. It also includes a guide cylinder and a moving rod. The guide cylinder is fixedly connected to one end of the lever. The moving rod passes through the guide cylinder and can move axially relative to the guide cylinder. The lower end of the moving rod is hinged to the magnetic traction assembly by a pin. The pin has an outwardly extending boss. The moving rod has a limiting groove. The boss extends at least partially into the limiting groove and slides with the limiting groove. The limiting groove has two opposite end walls on the sliding path of the sliding engagement.

[0007] Furthermore, the limiting groove is arc-shaped, and the center of the arc is located on the axis of the pin.

[0008] Furthermore, the width of the limiting groove in the arc-shaped extension direction is greater than the width of the boss in the same direction.

[0009] Furthermore, the end of the pin is provided with an annular groove, in which an elastic retaining ring is installed, and the elastic retaining ring abuts against the end face of the hole on the moving rod through which the pin passes.

[0010] Furthermore, the movable rod is connected to the inner wall of the guide cylinder via at least one roller; the roller is rotatably mounted on the movable rod.

[0011] Furthermore, there are multiple rollers, which are distributed at intervals along the circumference of the moving rod.

[0012] Furthermore, the movable rod is provided with a mounting groove, and the roller is mounted in the mounting groove via a rotating shaft; an elastic element is provided in the mounting groove, and the elastic element acts on the rotating shaft, causing the roller to have a tendency to move towards the inner wall of the guide cylinder.

[0013] Furthermore, a pressure block is provided between the elastic element and the rotating shaft.

[0014] The advantages of the magnetic manhole cover opening device described in this utility model compared to the prior art are as follows:

[0015] The movable rod can move axially along the guide cylinder fixed to the lever end. This axial floating structure absorbs the lateral displacement component caused by the lever rotation, thereby reducing the lateral shear force transmitted to the magnetic attraction assembly and the manhole cover adsorption interface. At the same time, through the sliding fit between the boss on the pin and the upper limit groove of the movable rod, as well as the end abutment, a mechanical hard limit is formed on the pitch angle of the magnetic attraction assembly, effectively limiting its tendency to overturn and avoiding the self-increasing slip component force due to attitude instability.

[0016] The aforementioned axial floating and angular limiting mechanisms work synergistically: the floating structure reduces initial disturbances that cause attitude changes, while the limiting structure ensures that attitude changes are always constrained within a safe range. Together, they allow necessary adaptive adjustments during dynamic prying while maintaining the stability of the adsorption core's attitude, thus systematically suppressing the overall slippage tendency of the magnetic traction assembly. Attached Figure Description

[0017] Figure 1 This is one of the front views of this utility model;

[0018] Figure 2 for Figure 1 Enlarged view of A in the middle;

[0019] Figure 3 This is a partial structural side view of the present invention;

[0020] Figure 4 This is the second front view of the present invention;

[0021] Figure 5 for Figure 4 A magnified view of B in the middle.

[0022] The attached diagram shows the following markings and corresponding component names: 10-Lever, 20-Support Shaft, 30-Magnetic Attachment, 40-Guide Cylinder, 50-Moving Rod, 60-Pin Shaft, 61-Boss, 62-Annular Slot, 63-Elastic Snap Ring, 70-Limiting Slot, 80-Roller, 90-Rotating Shaft, 100-Mounting Slot, 110-Elastic Component, 120-Pressure Block. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0024] Example:

[0025] refer to Figures 1-3 The device includes a lever 10, a support shaft 20, a magnetic suction assembly 30, a guide cylinder 40, and a moving rod 50. The support shaft 20 is located at the middle of the length of the lever 10. The lever 10 is rotatably supported on the support shaft 20. During operation, the support shaft 20 is placed at the edge of the wellhead, forming a fulcrum for prying.

[0026] The magnetic attraction assembly 30 includes a mounting base and a permanent magnet fixed to the lower end of the mounting base. The permanent magnet is used to attract the surface of the manhole cover.

[0027] The guide cylinder 40 is fixedly connected to one end (i.e., the working end) of the lever 10. Specifically, the guide cylinder 40 can be fixedly connected to the lever 10 by welding, bolting, or integral molding.

[0028] The movable rod 50 passes through the guide cylinder 40. To enable axial movement of the movable rod 50 relative to the guide cylinder 40, a movable gap is provided between the movable rod 50 and the guide cylinder 40. As a specific implementation, the outer diameter of the movable rod 50 is designed to be smaller than the inner diameter of the guide cylinder 40.

[0029] To prevent the movable rod 50 from completely disengaging from the guide cylinder 40 during movement, a limiting structure can be provided on the movable rod 50. For example, a flange, step, or locally thickened section can be formed on the rod body of the movable rod 50, and the outer diameter of the limiting structure portion is larger than the inner diameter of the guide cylinder 40.

[0030] The lower end of the movable rod 50 is hinged to the mounting base of the magnetic attraction assembly 30 via a pin 60. Specifically, the lower end of the movable rod 50 is provided with a first hinge hole, and the mounting base is provided with a corresponding second hinge hole. The pin 60 passes through the first hinge hole and the second hinge hole.

[0031] The pin 60 has an outwardly extending boss 61. A limiting groove 70 is formed on the shaft of the moving rod 50, and the boss 61 extends into the limiting groove 70. The boss 61 and the sidewall of the limiting groove 70 are in clearance fit, allowing the boss 61 to slide within the limiting groove 70. The limiting groove 70 has an end wall 71 at each end of the sliding path to block the boss 61 when it slides to its limit position.

[0032] In this embodiment, the limiting groove 70 is in the shape of an arc. The cross-sectional shape of the arc-shaped limiting groove 70 can be rectangular, U-shaped, or other suitable shapes. The center O of the arc trajectory of the limiting groove 70 is located on the axis of the pin 60. Thus, the sliding path of the boss 61 in the limiting groove 70 is concentric with the axis of the pin 60.

[0033] It is worth noting that, along the arcuate extension direction of the limiting groove 70, the minimum distance between its two side groove walls is defined as the groove width W1, and the maximum dimension of the boss 61 in the same direction is defined as the platform width W2. In this embodiment, the groove width W1 is greater than the platform width W2.

[0034] Based on the dimensional relationship W1 > W2, a movable gap is formed around the boss 61 between at least two sides of the boss 61 and the corresponding groove wall of the limiting groove 70. The size of this movable gap (i.e., the difference between W1 and W2) is configured to allow the boss 61 to slide without interference within the limiting groove 70.

[0035] Furthermore, an annular groove 62 is provided at one end of the pin 60 that protrudes from the hinged through hole of the moving rod 50. An elastic retaining ring 63 is installed in the annular groove 62. The elastic retaining ring 63 abuts axially against the end face of the hinged through hole on the moving rod 50 through which the pin 60 passes.

[0036] Specifically, the cross-sectional shape of the annular groove 62 is, for example, rectangular or V-shaped, and its depth and width are configured to stably accommodate the elastic retaining ring 63. After installation, the elastic retaining ring 63 partially protrudes beyond the annular groove 62. The outer diameter of the elastic retaining ring 63 in its free state is larger than the diameter of the hinged through hole of the moving rod 50.

[0037] As an optional implementation, a small axial gap may exist between the elastic retaining ring 63 and the end face of the moving rod 50. Alternatively, the elastic retaining ring 63 may maintain contact with the end face of the moving rod 50 due to its elastic restoring force.

[0038] refer to Figures 4-5In some embodiments, the outer peripheral surface of the movable rod 50 does not directly contact the inner peripheral surface of the guide cylinder 40, but is indirectly connected and supported by at least one roller 80. The roller 80 is located between the movable rod 50 and the guide cylinder 40 and is rotatably mounted on the movable rod 50.

[0039] After installation, the outer circumferential surface of the roller 80 remains in contact with the inner wall of the guide cylinder 40, thereby forming a rolling support interface between the moving rod 50 and the guide cylinder 40. The axis of rotation of the roller 80 is approximately parallel to the radial direction of the moving rod 50.

[0040] With this structure, when the moving rod 50 moves axially along the guide cylinder 40, the rolling friction between the roller 80 and the inner wall of the guide cylinder 40 provides motion guidance.

[0041] Furthermore, the number of rollers 80 is multiple, for example, three, four or more. These rollers 80 are evenly spaced along the circumference of the moving rod 50. Specifically, the rotation axes of the multiple rollers 80 are located in the same plane perpendicular to the axis of the moving rod 50, or are staggered along the axial direction of the moving rod 50.

[0042] In the assembled state, the outer circumferential surfaces of the plurality of rollers 80 are in contact with the inner wall of the guide cylinder 40. Each roller 80 independently bears a portion of the radial load from the moving rod 50. Thus, the plurality of rollers 80 form discontinuous, segmented annular contact areas with the inner wall of the guide cylinder 40 along the entire circumferential direction of the moving rod 50, collectively constraining the moving rod 50 at multiple points in the circumferential direction.

[0043] More importantly, at least one mounting groove 100 is recessed radially along the shaft of the movable rod 50. The opening of the mounting groove 100 faces the inner wall of the guide cylinder 40. The roller 80 is rotatably mounted via a pivot 90. The pivot 90 passes through the central hole of the roller 80, and its two ends extend and are supported in the corresponding mounting grooves 100.

[0044] To achieve elastic pressing, an elastic element 110 is provided between the bottom of at least one of the mounting grooves 100 and the rotating shaft 90. The elastic element 110 is axially accommodated within the mounting groove 100. One end of the elastic element 110 abuts against the bottom wall of the mounting groove 100, and the other end interacts with the outer peripheral surface or end of the rotating shaft 90.

[0045] In the assembled state, the elastic element 110 is in a compressed, pre-tightened state. Thereby, the elastic element 110 continuously applies a biasing force to the rotating shaft 90 in the direction of the opening of the mounting groove 100 (i.e., towards the inner wall of the guide cylinder 40). This biasing force is transmitted through the rotating shaft 90 to the roller 80, forcing the outer circumferential surface of the roller 80 to press against the inner wall of the guide cylinder 40.

[0046] Optionally, the elastic element 110 may be a component with axial elasticity, such as a helical compression spring, wave spring, disc spring, or elastic rubber column. The depth of the mounting groove 100 is set to be greater than the length of the elastic element 110 in its free state to ensure that it can be pre-compressed.

[0047] Furthermore, within the radial mounting groove 100, between the elastic member 110 and the rotating shaft 90, an independent pressure block 120 is added. The pressure block 120 is entirely housed within the cavity of the radial mounting groove 100.

[0048] The pressure block 120 has a first end face and a second end face. The first end face faces the elastic member 110 and is used to directly contact or indirectly abut against the end of the elastic member 110. The second end face faces the rotating shaft 90 and is configured as a contact surface that matches the outer peripheral contour of the rotating shaft 90. For example, the contact surface may be an inwardly concave arc surface to partially enclose the rotating shaft 90; or it may be a plane to tangentially contact the generatrix of the rotating shaft 90.

[0049] The pressure block 120 is arranged in the radial mounting groove 100 such that when the elastic member 110 is in a compressed state, the first end face of the pressure block 120 abuts against the elastic member 110, and its second end face abuts against the outer peripheral surface of the rotating shaft 90. Thus, the pressure block 120 forms a force transmission intermediate between the elastic member 110 and the rotating shaft 90.

[0050] Optionally, the pressure block 120 may be made of metal or engineering plastic. Its thickness along the depth direction of the mounting groove 100 is less than the difference between the depth of the mounting groove 100 and the compressed length of the elastic member 110, so as to reserve space for the installation of the pressure block 120 and the compression of the elastic member 110.

[0051] Working principle:

[0052] During operation, the permanent magnet of the magnetic attraction component 30 is attracted to the surface of the well cover, and the support shaft 20 is placed at the edge of the well opening as a fulcrum for the lever 10.

[0053] When the operator presses down on the non-working end of the lever 10, the lever 10 rotates around the support shaft 20. During this process, the movement trajectory of the working end of the lever 10 is an arc.

[0054] Since one end of the lever 10 is fixedly connected to the guide cylinder 40, the guide cylinder 40 moves accordingly. The moving rod 50 passes through the guide cylinder 40, and there is a gap between the moving rod 50 and the guide cylinder 40 that allows axial movement. Therefore, the arcuate movement of the guide cylinder 40 will not force the lower end of the moving rod 50 (i.e., the attraction point of the magnetic component 30) to undergo a lateral displacement of the same magnitude. Instead, the moving rod 50 can move axially relative to the guide cylinder 40, thereby absorbing the forced lateral displacement component caused by the rotation of the lever.

[0055] The lower end of the movable rod 50 is hinged to the magnetic suction assembly 30 via the pin 60. When the lever 10 pries and lifts the manhole cover upward, the reaction force of the manhole cover acts on the magnetic suction assembly 30, causing it to tend to pitch and rotate around the pin 60.

[0056] At this time, the boss 61 on the pin 60 slides within the limiting groove 70 of the moving rod 50. The extension trajectory of the limiting groove 70 restricts the sliding path of the boss 61, thereby limiting the maximum pitch angle of the magnetic attraction assembly 30 relative to the moving rod 50.

[0057] Meanwhile, if the roller 80 is provided between the moving rod 50 and the guide cylinder 40, the roller 80 transforms the sliding friction between the moving rod 50 and the guide cylinder 40 into rolling friction. If the roller 80 is elastically pressed against the elastic member 110, it can automatically compensate for gaps and maintain stable rolling contact. If there are multiple rollers 80 distributed circumferentially, they provide uniform radial support for the moving rod 50, which helps maintain alignment.

[0058] The axial displacement capability and the angle limiting capability work together. Axial displacement reduces the lateral shear force transmitted to the contact surface between the magnetic suction component 30 and the manhole cover; angle limiting prevents the magnetic suction component 30 from over-rotating, avoiding self-inflicted lateral slippage due to excessive rotation angle. The combination of the two allows the adsorption surface of the magnetic suction component 30 to maintain a more stable normal contact with the surface of the manhole cover during prying.

[0059] Ultimately, by leveraging the operating force and through the motion conversion and posture constraint of the aforementioned structure, the lifting force is applied more effectively to the normal direction of the manhole cover, thereby opening the manhole cover smoothly and effortlessly, and reducing the risk of the magnetic suction component accidentally slipping off the surface of the manhole cover.

[0060] The various illustrative embodiments mentioned in this specification refer to specific structures described in connection with those embodiments that are included in at least one embodiment of the general description in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a structure is described in connection with any embodiment, it is intended that implementing such a structure in conjunction with other embodiments falls within the scope of this utility model.

Claims

1. A magnetic manhole cover opening device, comprising a lever, a support shaft, and a magnetic assembly, wherein the support shaft is located in the middle of the lever and is used to be placed at the edge of the manhole as a prying fulcrum, characterized in that, Also includes: A guide cylinder and a movable rod, wherein the guide cylinder is fixedly connected to one end of the lever, and the movable rod passes through the guide cylinder and can move relative to the guide cylinder along the axial direction of the guide cylinder; The lower end of the movable rod is hinged to the magnetic attraction assembly via a pin, and the pin is provided with an outwardly extending boss. The movable rod has a limiting groove, and the boss extends at least partially into the limiting groove and slides in cooperation with the limiting groove. The limiting groove has two end walls that are opposite to each other on the sliding path of the sliding cooperation.

2. The magnetic manhole cover opening device according to claim 1, characterized in that, The limiting groove is arc-shaped, and the center of the arc is located on the axis of the pin.

3. The magnetic manhole cover opening device according to claim 2, characterized in that, The width of the limiting groove in the arc-shaped extension direction is greater than the width of the boss in the same direction.

4. The magnetic manhole cover opening device according to claim 3, characterized in that, The end of the pin is provided with an annular groove, in which an elastic retaining ring is installed. The elastic retaining ring abuts against the end face of the hole on the moving rod through which the pin passes.

5. The magnetic manhole cover opening device according to claim 4, characterized in that, The movable rod is connected to the inner wall of the guide cylinder via at least one roller; the roller is rotatably mounted on the movable rod.

6. The magnetic manhole cover opening device according to claim 5, characterized in that, The number of rollers is multiple, and the multiple rollers are distributed at intervals along the circumference of the moving rod.

7. The magnetic manhole cover opening device according to claim 6, characterized in that, The movable rod is provided with a mounting groove, and the roller is mounted in the mounting groove through a rotating shaft; an elastic element is provided in the mounting groove, and the elastic element acts on the rotating shaft, so that the roller has a tendency to move towards the inner wall of the guide cylinder.

8. The magnetic manhole cover opening device according to claim 7, characterized in that, A pressure block is provided between the elastic element and the rotating shaft.

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