A snap-in pad dowel connection assembly

Abstract

The application relates to the technical field of transformer assembly, and discloses a buckle type cushion block nail pressing connecting assembly which comprises a nail pressing and a cushion block matched with the nail pressing. The nail pressing has a nail rod, an elastic pressing cap fixed to the upper end of the nail rod, and an elastic ring sleeved on the lower part of the nail rod. During installation, the nail pressing is placed above the installation hole of the flange plate of the lower clamp, the elastic pressing cap is knocked, the nail rod is driven to pass through the installation hole, at this time, the elastic ring is compressed and shrunk to pass through the installation hole and restore the deformation below the flange plate, and the elastic ring is locked on the flange plate together with the elastic pressing cap above the flange plate. The utility model realizes quick installation and disassembly without special tools, provides reliable connection and excellent anti-loosening performance through a double elastic buckle structure, simultaneously obviously simplifies the structure, and reduces the cost.

Description

Technical Field

[0001] This utility model relates to the field of transformer component technology, and more specifically, to a snap-fit ​​pad pin connection component. Background Technology

[0002] In the assembly of dry-type or oil-immersed transformers, axial clamping of the coils is typically achieved through a pad and clamping pin structure to ensure stability and prevent displacement or loosening due to electromagnetic vibration, thermal expansion and contraction, or transportation bumps. Traditional clamping pin structures often use a bolt and nut combination. For example, Chinese Patent CN210068700U discloses a transformer clamping pin structure that uses a threaded rod, clamping pin head, and elastic element (such as a disc spring) to subject the coil to both rigid pressure and elastic preload, thus improving the anti-loosening effect. However, this structure still requires tightening bolts and nuts, making the assembly process relatively cumbersome and involving many parts. Another prior art, such as Chinese Patent CN222440324U, focuses on an anti-horizontal displacement structure between the pad body and the channel steel, using an auxiliary positioning component and a sliding groove to lock the bolts. While this enhances horizontal stability, its core fixing still relies on bolt tightening, and does not simplify the installation process.

[0003] Existing bolted connection methods have the following main drawbacks: 1. Installation and disassembly require specialized tools such as wrenches, which are inconvenient to operate within the limited space of a transformer; 2. Under long-term vibration, bolted connections still carry the risk of loosening, requiring regular inspection and maintenance; 3. The large number of parts (bolts, nuts, washers, etc.) results in relatively high material and management costs. This is particularly true for fixing the pads on the lower clamping parts of a transformer (usually a channel steel structure), where tightening bolts from below is especially inconvenient. Therefore, there is an urgent need for a pad clamping pin structure specifically designed for lower clamping parts installation scenarios, requiring no specialized tools, offering quick and reliable operation, and lower costs. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a snap-fit ​​pad pin connection assembly, which enables quick installation through snap-fit ​​connection, requires no special tools, and provides reliable axial limiting and anti-loosening effects.

[0005] To achieve the above objectives, this utility model provides the following technical solution: A snap-fit ​​pad and pin connection assembly is applied to a transformer. The transformer includes a lower clamp and a pad. The lower clamp includes a horizontally arranged flange plate with a mounting hole. The connection assembly includes a pin and a pad. The pin includes a pin rod and a cap fixedly disposed at the upper end of the pin rod. The pin rod is used to pass through the mounting hole from top to bottom. At least one elastic retaining ring is provided on the pin rod, and the elastic retaining ring is located below the flange plate. The radial dimension of the elastic retaining ring in its natural state is larger than the hole of the mounting hole. The pressure cap is made of elastic material and its radial dimension is larger than the diameter of the mounting hole. Its lower end is used to abut against the upper end face of the flange plate. The lower end face of the pad has a snap-fit ​​groove opposite the pressure cap. The pressure cap deforms and embeds into the snap-fit ​​groove when compressed. After embedding, it forms an interference fit with the side wall of the snap-fit ​​groove through its elastic restoring force.

[0006] Furthermore, the distance between the lower end face of the pressure cap and the upper end face of the elastic retaining ring is greater than or equal to the thickness of the flange plate.

[0007] Furthermore, the lower end of the nail rod is provided with a tapered tip for easy insertion, and the elastic retaining ring is disposed above the tapered tip.

[0008] Furthermore, the nail rod is provided with an annular limiting boss, which is located at the lower end of the elastic retaining ring to prevent the elastic retaining ring from sliding off downwards along the nail rod.

[0009] Furthermore, the pressure cap is mushroom-shaped, comprising a columnar root connected to the nail rod and an enlarged head located at the upper end of the columnar root, wherein the upper surface of the enlarged head is a spherical or conical guide surface.

[0010] Furthermore, the pressure cap is cylindrical.

[0011] Furthermore, the length of the snap-fit ​​groove is greater than the diameter of the pressure cap, and the width of the snap-fit ​​groove is less than the diameter of the pressure cap.

[0012] Furthermore, the nail rod and the pressure cap are integrally formed.

[0013] Furthermore, the nail rod is made of metal.

[0014] Furthermore, the nail rod and the elastic retaining ring are integrally formed structures, both made of elastic material.

[0015] The beneficial effects provided by this utility model are as follows: This invention completely eliminates the need for the traditional tightening of bolts. During installation, simply align the pressure pin with the mounting hole of the lower clamp flange and apply downward pressure to the pressure cap to drive the pin rod downward. The elastic retaining ring on the pin rod undergoes radial elastic contraction as it passes through the mounting hole, and instantly recovers after passing through the hole, clamping itself under the flange plate. Together with the pressure cap above, it forms a clamping fixation for the flange plate, a process completed in one step. Subsequently, align the snap-fit ​​groove of the pad with the pressure cap and apply downward pressure to the pad, causing the elastic pressure cap to deform, embed, and recover, thus completing the fixation of the pad. The entire assembly process requires no wrenches, screwdrivers, or any special tools; it can be completed with just two simple taps or presses, greatly simplifying the operation steps. It is particularly suitable for efficient assembly inside transformers where space is limited, significantly improving assembly efficiency. After recovering its deformation, the contact between the elastic retaining ring and the lower surface of the flange plate provides a continuous, non-threaded holding force, effectively resisting the axial loosening tendency caused by transformer electromagnetic vibration and thermal expansion and contraction. After the pressure cap is embedded in the snap-fit ​​groove, the elastic restoring force of its material generates continuous static friction and radial clamping force between its sidewall and the sidewall of the snap-fit ​​groove, forming a stable snap-fit. This dual elastic constraint structure has better vibration resistance and anti-loosening performance than traditional bolts that rely solely on thread friction. When replacement or maintenance is required, simply use a pry bar or other simple tools to pry the pad upwards, allowing the pressure cap to elastically disengage from the snap-fit ​​groove and remove the pad. Then, use an appropriate tool to push the pressure pin upwards from below, causing the elastic retaining ring to retract radially, allowing the pressure pin to be completely removed from the mounting hole. The entire disassembly process is the reverse of the installation process, making it simple and quick. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a three-dimensional structural diagram of the snap-fit ​​pad pin connection assembly provided by this utility model; Figure 2 This is a three-dimensional structural diagram of the pad block in the snap-fit ​​pad block pin connection assembly provided by this utility model; Figure 3 This is a schematic diagram of the assembly of the snap-fit ​​pad pin connection assembly provided by this utility model.

[0018] Figure label: 1-Lower clamping part; 11-Flange plate; 2-Padded block; 21-Snap-fit ​​groove; 3-Pressure nail; 31-Pressure cap; 32-Nail shaft; 33-Conical tip; 34-Elastic retaining ring. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] It should be noted that the directional terms such as "upper," "middle," "lower," "inner," and "outer" used below are defined based on the accompanying drawings in the instruction manual.

[0022] Please refer to Figures 1 to 3 A snap-fit ​​pad pin connection assembly is provided for quickly fixing a transformer pad 2 onto a lower clamp 1. The lower clamp 1 is typically a channel steel structure with a horizontal steel flange 11, on which circular mounting holes are pre-drilled. The pad 2 is a rectangular block made of insulating material, with a transverse strip groove machined on its lower end face as a snap-fit ​​groove 21.

[0023] The core of the connecting assembly is the pressure nail 3. The pressure nail 3 is an integrated component, mainly including the nail rod 32 as the main body, the pressure cap 31 fixed to the upper end of the nail rod 32, and the elastic retaining ring 34 sleeved on the lower part of the nail rod 32.

[0024] The nail shank 32 is a straight rod with a diameter slightly smaller than the mounting hole diameter to ensure smooth passage. The lower end of the nail shank 32 is machined with a conical tip 33. The main function of this conical tip 33 is to guide the nail shank 32 to align smoothly and enter the mounting hole during the initial installation stage, reducing alignment difficulty. The nail shank 32 is preferably made of a metallic material, such as Q235 steel, to ensure sufficient structural strength and rigidity to transmit and withstand the clamping force.

[0025] The elastic retaining ring 34 can be a standard rubber O-ring, which is fitted and fixed on the nail shank 32 and located above the conical tip 33. In a natural, unloaded state, the outer diameter of the elastic retaining ring 34 is larger than the diameter of the mounting hole on the lower clamping flange plate 11. The nail shank 32 may be machined with an annular groove or provided with an annular boss for axial positioning of the elastic retaining ring 34, preventing it from accidentally slipping off along the nail shank 32 during transportation or installation.

[0026] The pressure cap 31 is made of an engineering plastic with good elasticity and fatigue resistance, such as nylon or polyoxymethylene. The pressure cap 31 is fixedly connected to the top of the nail shank 32. Its radial dimension, i.e., diameter or maximum width, is designed to be larger than the diameter of the mounting hole. The shape of the pressure cap 31 can be designed as a simple cylindrical elastomer. Correspondingly, the snap-fit ​​groove 21 on the pad 2 can be designed as a matching circular blind hole or through hole.

[0027] The key relative dimensions of each component must meet the following design requirements: the axial distance between the lower end face of the pressure cap 31 and the upper end face of the elastic retaining ring 34 should be greater than or equal to the thickness of the flange plate 11 of the lower clamping member. This dimensional relationship is the basis for the reliable clamping and fixing of this solution. It ensures that when the pressure pin 3 is installed in place, the flange plate 11 can be firmly constrained between the lower end face of the pressure cap 31 and the upper end face of the elastic retaining ring 34 without axial movement or gap.

[0028] The assembly and working process is as follows: The first step is to install the pressure pin 3 onto the lower clamp 1. The operator places the pressure pin 3 above the flange plate 11 of the lower clamp 1, aligning the tapered tip 33 of the pin shank 32 with the mounting hole on the flange plate 11. Then, using a rubber mallet or similar tool, the top of the pressure cap 31 is struck vertically downwards. The striking force drives the entire pressure pin 3 downwards. When the elastic retaining ring 34 contacts the edge of the mounting hole, it is compressed by the edge of the hole, causing it to radially elastically contract, making its instantaneous outer diameter smaller than the hole diameter, thus allowing it to pass smoothly through the hole. At the instant the elastic retaining ring 34 completely passes through the mounting hole, it loses the constraint of the hole wall and rapidly returns radially to its original size due to the elasticity of its rubber material. Because the recovered outer diameter is larger than the hole diameter, the upper side or end face of the elastic retaining ring 34 firmly abuts against the lower surface of the flange plate 11. Simultaneously, the lower end face of the pressure cap 31 also abuts against the upper surface of the flange plate 11 under the impact force. Thus, the pressure nail 3, through the pressure cap 31 above and the elastic retaining ring 34 below, achieves the upper and lower clamping of the lower clamping flange plate 11, and is reliably axially locked in the predetermined position.

[0029] The second step is to install the pad 2. Place the pad 2 at the predetermined position above the transformer coil and between the lower clamp 1, and adjust the pad 2 so that the snap-fit ​​groove 21 at its lower end aligns with the cap 31 of the pre-installed clamping nail 3. Then, tap the upper surface of the pad 2 downwards. Under pressure, the top of the cap 31 first contacts the entrance edge of the snap-fit ​​groove 21. As the pad 2 continues to descend, the cap 31 is squeezed by the side wall of the snap-fit ​​groove 21, and its upper part undergoes elastic compression deformation (mainly radial contraction), thus allowing it to enter the relatively narrow snap-fit ​​groove 21. When the cap 31 is fully embedded in the snap-fit ​​groove 21, the external tapping force stops, and the elastic material of the cap 31 attempts to return to its original shape. However, due to the limitation of the width of the snap-fit ​​groove 21, a tight interference fit is formed between its side wall and the side wall of the snap-fit ​​groove 21, thereby generating a strong static friction force and radial clamping force, thus firmly fixing the pad 2 to the clamping nail 3. This process not only achieves mechanical connection, but also the elastic deformation and recovery characteristics of the pressure cap 31 provide a continuous, flexible elastic preload for the pad block 2 and the transformer coil pressed by it, which helps to compensate for minor deformation or loosening that may occur during operation.

[0030] As another feasible implementation, the pressure cap 31 can be designed in the shape of a mushroom head, with a smooth spherical or conical guide surface at the top. This shape is beneficial for guiding its own deformation when subjected to downward pressure. Its installation and fixing principle is the same as that of Embodiment 1, which relies on the pressure cap 31 undergoing elastic deformation under impact to enter the locking groove 21, and then relying on its elastic restoring force to form an interference fit with the groove wall to achieve reliable locking.

[0031] In another variant embodiment, the pressure pin 3 can be designed as an all-plastic structure. Specifically, the pin shank 32 and the pressure cap 31 can be manufactured as a single integral component using a high-strength engineering plastic (such as glass fiber reinforced nylon) through an integrated injection molding process. In this case, the function of the elastic retaining ring 34 can be achieved by directly molding multiple or a single elastic arc-shaped protrusion or barb structure around the pin shank 32 of the integrally molded part, with the protrusion and pin shank 32 being made of the same material. This all-plastic integrated solution can further reduce the weight and manufacturing cost of the product while maintaining excellent insulation performance, making it suitable for applications with special insulation requirements.

[0032] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0033] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0034] The above provides a detailed description of the snap-fit ​​pad pin connection assembly provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that those skilled in the art can make several improvements and modifications to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A snap-fit ​​pad pin connection assembly, applied to a transformer, the transformer including a lower clamp and a pad, the lower clamp including a horizontally arranged flange plate, the flange plate having mounting holes; characterized in that, The connecting assembly includes a pressure pin and a pad; the pressure pin includes a pin shaft and a pressure cap fixedly disposed at the upper end of the pin shaft; the pin shaft is used to pass through the mounting hole from top to bottom; the pin shaft is provided with at least one elastic retainer, the elastic retainer being located below the flange plate; the elastic retainer has a radial dimension larger than the diameter of the mounting hole in its natural state, and can generate radial elastic contraction to pass through the mounting hole when axially compressed, and radially recovers after passing through the mounting hole, so as to prevent the pin shaft from coming out of the mounting hole upward; the pressure cap is made of elastic material, its radial dimension is larger than the diameter of the mounting hole, and its lower end is used to abut against the upper end face of the flange plate; the lower end face of the pad is provided with a snap-fit ​​groove opposite the pressure cap, the pressure cap deforms and embeds into the snap-fit ​​groove when compressed, and after embedding, it forms an interference fit with the side wall of the snap-fit ​​groove through its elastic restoring force to fix it.

2. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The distance between the lower end face of the pressure cap and the upper end face of the elastic retaining ring is greater than or equal to the thickness of the flange plate.

3. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The lower end of the nail rod is provided with a tapered tip for easy insertion, and the elastic retaining ring is disposed above the tapered tip.

4. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The pressure cap is cylindrical.

5. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The length of the snap-fit ​​groove is greater than the diameter of the pressure cap, and the width of the snap-fit ​​groove is less than the diameter of the pressure cap.

6. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The nail rod and the pressure cap are integrally formed.

7. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The nail rod is made of metal.

8. The snap-fit ​​pad pin connection assembly according to claim 1, characterized in that, The nail rod and the elastic retaining ring are integrally formed structures, both made of elastic material.

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