CN116710615A

CN116710615A - Pile mechanical joint with one or more slotted locking protrusions for easy installation of one or more locking pins

Info

Publication number: CN116710615A
Application number: CN202180083691.4A
Authority: CN
Inventors: 陈其键
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-12-22
Filing date: 2021-10-07
Publication date: 2023-09-05
Also published as: AU2021410532A1; EP4267803A1; KR20230122029A; WO2022139571A1; JP2023553842A

Abstract

A pile mechanical locking mechanism with one or more screw-in grooved locking protrusions (3) is provided, whereby by flexing of the non-welded, screw-in grooved protrusion(s) (3) and the locking pin(s) (7) in contact with a small part of the grooved protrusion(s) (3), the locking pin(s) (7) are easily installed even if common debris from the piling phase is present or even if dimensional tolerances of the connection plate (1) of the pile are not ideal due to manufacturing errors or external force damage. The mechanical locking mechanism is open or exposed in nature, thus facilitating the removal of debris and visual inspection of any possible physical obstruction of successful installation of the locking pin or pins (7).

Description

Pile mechanical joint with one or more slotted locking protrusions for easy installation of one or more locking pins

Technical Field

The present invention relates to piles for building foundations, and more particularly to pile segments and pile joints therefor.

Background

Conventionally, precast piles are produced in sections. In order to enable the piles to be installed deep in the ground (beyond the depth of the individual sections of piles), the individual piles are lengthened by connecting the individual sections by steel joints. There are mainly two types of steel joints, mechanical and welded.

Basically, a conventional welded steel joint for piles consists of the following steel members:

anchor rod (optional for prestressed pile)

One or more screw holes (normally used for prestressed piles)

Connecting plate

Skirting board

Typical welded steel joints are welded along the perimeter of the web. Sometimes welded steel connection plates are made into male (with protruding bars) and female (with steel pipes to accommodate the protruding bars of the male connection plates) connection plates; sometimes, welded connection plates are made identical (no protruding bars or pipes).

The anchor rods connected to the connection plates are used to transfer the stresses to which the pile is subjected, but in general some connection plates for prestressed piles do not have anchor rods, but instead the connection plates transfer the stresses to the prestressed steel wires, strands or tendons of the prestressed pile.

Current prestressed piles are usually attached to their connection plates by hooking the connection plates to the pile by means of prestressed wires, steel strands or tendons which, by performing other processes, compress and expand the ends into mushroom-shaped buttons, the expanded mushroom-shaped buttons being hooked end-on to the connection plates to secure the connection plates to the pile.

In the production process of the prestressed piles, connecting plates are placed at two ends of the pile mould, and steel connecting plates are placed at two opposite ends. The connection plates are fully secured by being secured to the pre-stressing wires, strands or tendons (for pre-stressed piles) or to the gates of the pile forms (for non-pre-stressed piles).

At present, such pile joints for connecting pile segments have been greatly improved. Examples of such joints are found in GB2363150a- "socket-and-spigot pile connections", which describe the connection of pile segments by introducing a spigot into a socket. The internal dimensions of the socket are sufficient to insert the plug without interference, thereby forming a joint without introducing other materials into the socket (although hot melt adhesive may be introduced into the socket). However, this method is expensive and not popular.

In WO2020094923- "pile joint" one or more pins are provided with machined holes for inserting one or more locking pins (the locking pin(s) enter the machined holes of the pin(s) to prevent the pin(s) from loosening). The locking pin is introduced from the outside of the pile and passes through the cylindrical cavity before contacting the one or more pins. This type of pile mechanical joint has been widely used and has fairly consistent performance, but requires a considerable thickness of the connection plate due to the thermal strain caused by welding one or more pins to the connection plate. Another common problem with this type of pile mechanical joint is that the cylindrical cavity through which the locking pin passes may be blocked or clogged by concrete during the pile concrete casting stage or by debris common to the pile driving stage, making this type of pile mechanical joint difficult to install or even inoperable.

In WO2015026223- "concrete pile end plates" one or more locking pins are fully hammered in to lock the pile joint through the full length (or most of the length) of the locking pin(s). This type of pile mechanical joint is expensive, susceptible to debris (which may be introduced at any time during the piling phase), and requires a very high level of machining tolerances in the manufacture of the pile mechanical joint components to ensure successful operation. The high cost, need for high manufacturing quality, and susceptibility of such a pile mechanical joint to failure by debris or dimensional errors make this type of pile mechanical joint less popular.

Furthermore, in order to achieve the connection of piles, there is a common problem with connection plates that need to be welded along the periphery, i.e. the quality of the weld is often questioned. In view of the fact that the welding of the periphery of the connection plate is performed outdoors rather than in a factory, the environmental impact may have an adverse effect on the welding quality. Furthermore, the weld quality is also directly dependent on the skill of the welder, which can be a problem with quality fluctuations and human error, and can severely impact the performance of the welded pile joint.

Thus, there is a need to design a cheaper, more efficient and sufficiently strong pile connection system that is easy to implement and that is able to meet any load bearing requirements while having consistent, reliable performance.

Disclosure of Invention

The present invention does not require welding the perimeter of the connection plate, which is necessary in the case of conventional welded joint designs, which have been found to be time consuming, where the quality of the final performance of the welded pile joint is largely dependent on the welder's skill.

The main components of the invention are described in detail as follows:

(1)one or more grooved protrusions

The head of one or more grooved protrusions is lathed into a mushroom shape with a bolt base or stem. The head has a diameter greater than the diameter of the bolt base or shank. The head of the one or more grooved protrusions should be precisely machined by a lathe to make uniform contact with the locking pin, which may be circular in cross section, and to ensure consistent working tolerances by accurately projecting from the web even in the event of dimensional errors in the web.

(2)One or more threaded holes for one or more grooved protrusions

One or more of the grooved protrusions are formed with a bolt base or shank. The stake attachment plates should be drilled and tapped to form threaded bores for receiving one or more bolt bases or stems with grooved protrusions.

(3)One or more receiving cavities for receiving one or more grooved raised heads of a connection plate of an opposing pile

One or more circular cavities are milled a set distance beside the one or more threaded bores using a flat end mill having a diameter slightly larger than the diameter of the head of the one or more fluted protrusions. The one or more cavities should receive one or more grooved protrusions of a connection plate of an opposing pile. In addition, a T-slot side mill may be used to further form a notch in which the lip of one or more fluted protrusions is placed to increase the locking strength.

(4)Milling grooves (grooves) or slots (slots) for locking pins in pile connecting plates

A slot or groove aperture is milled between the one or more threaded bores and the one or more receiving cavities using a side mill instead of an end mill to form a passageway through which the locking pin passes. The grooves or slots are machined in such a way that when the two connection plates are combined, a complete channel is formed by the two grooves or slots, so that the locking pin is inserted from the outside of the pile to contact the grooved protrusions. Substantially each slot or groove aperture forms half of the channel through which the locking pin will pass, and two slots or groove apertures form one complete channel.

(5)One or more locking pins

The locking pin or pins are typically cylindrical steel bars for insertion between two grooved protrusions (one head up and the other head down) after the two pile connecting plates are in contact. The one or more locking pins are inserted into the channel formed by the two grooves or slots of the two contacting connection plates and after the one or more locking pins are in contact with the grooved protrusions, the locking pins are hammered in to lock the pile sub together.

The present invention is essentially a mechanical joint locking mechanism for a pile joint comprising one or more slotted protrusions having a bolt base or shank, and corresponding one or more threaded holes in the connection plate of the pile; one or more receiving cavities (for receiving the opposing one or more protrusions of the opposing connector); the one or more milling grooves or slots in the connecting plate of the pile and its corresponding cross section may be one or more locking pins of any shape. The shape of the slot in the one or more slotted protrusions should depend on the cross-sectional shape of the one or more locking pins. The one or more slotted protrusions are in partial contact with a surface of the one or more locking pins. Further, since the one or more slotted protrusions only partially surround the perimeter of the one or more locking pins, this discontinuous manner allows the one or more slotted protrusions to flex somewhat, thereby facilitating insertion of the one or more locking pins. Load transfer (e.g., tensile load) will be transferred from the upper slotted projection to the lower slotted projection with the locking pin located between the upper and lower slotted projections.

The present invention does not require welding one or more grooved protrusions to the connection plate, but rather assembles the one or more grooved protrusions to the connection plate of the pile by threading the threaded portion of the one or more grooved protrusions onto the connection plate itself. Because no welding is required, no thermal strain is created by the welding, no thick web is required to distribute or withstand the thermal strain, and because there is no welding between the one or more grooved protrusions and the web, some flexing or lateral movement of the one or more grooved protrusions is possible, thus making the locking pin easy to install.

Further, movement of the one or more locking pins and friction with the one or more grooved protrusions creates a tightening torque due to the bolt base or shank of the one or more grooved protrusions. This increases the prestress of the locking mechanism and also serves to ensure the quality of the correct assembly of the locking mechanism when the mounting or hammering of the locking pin or pins is completed. The locking pin is also easy to install or hammer in, since the grooved protrusions are screwed onto the connection plate instead of welded onto the connection plate, and the grooved protrusions are rotatable. The contact of each locking pin with two slotted protrusions (one from each side of the opposite web) ensures that tensile loads can be borne.

One or more of the grooved protrusions of the present invention are threaded onto the web of the stake and each grooved protrusion, wherein the one or more grooved protrusions are precisely machined to meet operating tolerances. Inaccurate machining tolerances, damage or deformation of the connection plates often result in difficult or even impossible operation of the prior art mechanical joint, and thus do not present the problem for the present invention, given that one or more grooved protrusions themselves have the required tolerances when manufactured together. Once one or more grooved protrusions are screwed onto the connection plate, the protrusion (which is critical to the operating tolerances of the invention) is always accurate and independent of the dimensional conditions of the connection plate, due to the precision with which the grooved protrusions themselves have.

For the present invention, a typical implementation of the operation of the pile mechanical joint involves two opposing pile joints (the grooved protrusions are properly threaded into the respective threaded holes) being put together with the grooved protrusions all into the receiving cavity until the webs of the two piles are in full contact. When inserting one or more locking pins (a channel formed by the combination of two milled grooves or slots of two opposite webs), the locking of the pile sub is typically done by hammering such that the locking pin or pins come into contact with the protruding groove or grooves, thereby preventing the two pile sub from separating. The one or more locking pins will serve to transfer tensile loads and also prevent the webs from separating after the one or more locking pins are installed.

The open or exposed nature of the one or more fluted protrusions, the milling flutes or slots for the one or more locking pins, and the one or more receiving cavities means that debris is easily cleared and any possible physical obstruction to successful installation of the one or more locking pins is easily visually inspected.

Differences between the present invention and the three cited prior art pile mechanical joints will be described and addressed in detail below:

(a) In WO2020094923- "pile joint" one or more locking pins are inserted into one or more pins with machined holes, which has the disadvantage of being expensive and requiring high machining tolerances of the components to ensure easy installation of the locking pin or pins. Typical deformation on the pile connecting plate (which often occurs in typical piling operations) or over-working of the components may result in one or more locking pins being difficult or even impossible to hammer in. Furthermore, this type of prior art makes it difficult or even impossible to install one or more locking pins when the mechanism is contaminated with common debris introduced during the piling operation. The present invention does not have a machined hole, but rather cuts (or mills) a groove that is discontinuous in nature in one or more protrusions. For clarity, the machined holes of the prior art are cavities with continuous steel that completely surround the perimeter of the locking pin or pins, while the fluted protrusion or protrusions of the present invention do not surround the entire perimeter of the locking pin or pins and are therefore described as discontinuous. If the present invention is subject to inaccurate machining tolerances, or if the web is damaged and slightly deformed by the staking operation, the discontinuity of the one or more slotted protrusions of the present invention will still allow the one or more locking pins to be easily staked or installed because the one or more slotted protrusions are able to flex or bend slightly, which the prior art (the pin or pins with machined holes) would not allow. Because of the inherent ability of the present invention to allow the one or more fluted protrusions to flex, the presence of common debris in the mechanism at the pile driving stage does not affect the present invention as it does in the prior art, thus making the present invention virtually chipproof and easy to install one or more locking pins.

The prior art of the type described above requires welding one or more pins to the connection plate and does not use the one or more slotted raised bolt bases or bars of the present invention, which do not require welding and which can generate some tightening torque and increase pre-stressing when the one or more locking pins are fully installed. The present invention eliminates the need for welding so as to allow additional flex in the one or more slotted protrusions, thereby allowing for easy installation of the one or more locking pins.

(b) In the second type of prior art, WO2015026223- "end plates of concrete piles" it is necessary to participate in or be used for the locking mechanism by the full length (or the majority of the length) of one or more locking pins. A problem with this type of prior art is that high machining tolerances are required and that most or all of the length of one or more locking pins also be wedged into the locking mechanism. Machining errors, deformation or damage due to the piling operation may make it extremely difficult or even impossible for one or more locking pins to be hammered into or installed. This is not to say that in all cases such prior art locking pin or pins are difficult to insert, sometimes the locking pin or pins are easy to insert, but the likelihood of such prior art locking pin or pins being difficult to insert is much greater than in the present invention. The presence of common debris introduced during the piling phase makes it extremely difficult or even impossible for the prior art locking pin or pins to be installed. The present invention does not require that a majority of the length of one or more locking pins be wedged into place as in the prior art. The present invention requires only a small portion of the one or more locking pins to be in contact with the one or more grooved protrusions, which requires that for the prior art a large portion of the length of the one or more locking pins be used directly for the force transmission of the locking mechanism. The locking pin or pins of the present invention need not have any contact with the connection plate at all, as the grooved protrusion or protrusions transfer tension or bending forces directly to the locking pin or pins without the involvement or influence of the connection plate. This is in contrast to the prior art, in which the connection plate is not only in contact with the locking pin or pins, but the tensile or bending forces are actually transmitted directly from the connection plate to the locking pin or pins. The partial contact of the invention makes the invention virtually chipproof and easy to insert into one or more locking pins.

The prior art of the type described above does not use the bolt base or shank of the one or more slotted projections of the present invention, which does not require welding and which is capable of generating some tightening torque and additional prestress when the one or more locking pins are fully installed, as well as allowing some flexing of the one or more slotted projections, so that the one or more locking pins are easy to install.

The main object of the present invention is to provide a mechanical pile coupling which is easy to install due to the discontinuous nature of the one or more grooved protrusions and due to the contact of the one or more locking pins with the parts of the one or more grooved protrusions, and which is easier to install because it is not necessary to wedge a large part of the one or more locking pins into place so that the mechanical locking of the pile connecting plate can take its full function.

Another object of the present invention is to create a mechanical joint for piles which is simple in nature and which will provide or produce consistent performance due to its inherent simplicity.

A further object of the present invention is to create an economical mechanical pile joint which, although economical, does not affect its performance.

The above and other objects, features and advantages of the present invention will become more apparent from the following description when read in conjunction with the accompanying drawings.

Drawings

Fig. 1 shows a simplified typical square pile and a simplified typical standard welded connection plate of hollow cylindrical tubular piles.

Fig. 2 illustrates the present invention on a typical tube stake connection plate on a typical tube stake.

Fig. 3 shows an exemplary embodiment of the invention, wherein the cross-sectional shape of the locking pin is square.

Fig. 4 shows an exemplary embodiment of the present invention, in which the cross-sectional shape of the locking pin is circular.

Fig. 5 shows an exemplary embodiment of the invention with the grooved protrusion on the left and the locking pin on the right.

Detailed Description

Fig. 1 shows a conventional welded connection plate (1) for a simplified typical square pile and a simplified typical hollow cylindrical pipe pile, which the present invention seeks to replace. The upper left is a plan view of a typical tubular pile connecting plate (1), the upper right is a plan view of a typical square pile connecting plate (1), the lower left is a side view of a typical tubular pile connecting plate (1), and the lower right is a side view of a typical square pile connecting plate (1). The connecting plate (1) is poured or installed at the end of the precast pile, and when the deep pile penetration depth is required, the connecting plate (1) is welded along the whole periphery of the contact connecting plate (1), so that the length of each part of the precast pile is prolonged.

Fig. 2 shows the pile mechanical joint of the present invention on a pipe pile connection plate (1). In fig. 2 (a), the connection plates (1) of the pipe piles have threaded holes (2) which are initially used in the pipe pile manufacturing process for applying prestress to the prestress wire, strand or tendon of the pipe piles and also for fixing the connection plates (1) to the pile mould, the invention will use these same threaded holes (2) for mounting the grooved protrusions (3), the receiving cavities (4) for receiving the grooved protrusions (3) of the opposite connection plates (1) of the top pipe piles (5), and when the milled grooves or slots (6) of the top connection plates (1) and the bottom connection plates (1) are fully contacted, complete passages for locking pins (7) will be formed which will be installed to complete the locking process of the connection plates (1) to effect connection of the top pile connection plates (1) to the bottom pile connection plates (1). The single milling groove or slot (6) forms half of the complete channel of one locking pin (7), and when the top connection plate (1) and the bottom connection plate (1) are fully contacted, the two contacted milling grooves or slots (6) of the top connection plate (1) and the bottom connection plate (1) form the complete channel of one locking pin (7) to the grooved protrusion (3). As shown in fig. 2 (b) and 2 (c), the top pile (5) and the bottom pile (8) are connected after their one or more locking pins (7) are fully installed.

Fig. 3 shows an exemplary embodiment of the invention, in which the cross-sectional shape of the locking pin (7) is square. The upper drawing shows an unassembled locking mechanism of the invention, wherein the top web (1) and the bottom web (1) have grooved protrusions (3), respectively, a receiving cavity (4) for receiving the opposing grooved protrusions (3), and a milled groove or slot hole (6). The following figure shows the invention, only the locking pin (7) being uninstalled in order to more clearly understand the complexity of the invention. The lower drawing shows the top web (1) and the bottom web (1) in contact, the respective grooved protrusions (3) of the top web (1) and the bottom web (1) being located in the respective receiving cavities (4), and the rest of the operation being the mounting of the locking pins (7) into the channels formed by the two milling grooves or slots (6). The mounting of the locking pin (7) will prevent the disengagement of the two slotted protrusions (3) because the locking pin (7) blocks the disengagement channel of the slotted protrusions (3) thereby locking the two pile connecting plates (1) together.

Fig. 4 shows an exemplary embodiment of the invention, wherein the cross-sectional shape of the locking pin (7) is circular. The upper drawing shows an unassembled locking mechanism of the invention, wherein the top web (1) and the bottom web (1) have grooved protrusions (3), respectively, a receiving cavity (4) for receiving the opposing grooved protrusions (3), and a milled groove or slot hole (6). The following figure shows the invention, only the locking pin (7) being uninstalled in order to more clearly understand the complexity of the invention. The lower drawing shows the top (1) and bottom (1) webs in contact, the webs (1) and the respective grooved protrusions (3) of the bottom (1) webs of the top piles (5) being located in the respective receiving cavities (4), and the remainder of the operation being the mounting of the locking pins (7) into the channels formed by the two milled or slotted holes (6). The mounting of the locking pin (7) will prevent the disengagement of the two slotted protrusions (3) because the locking pin (7) blocks the disengagement channel of the slotted protrusions (3) thereby locking the two pile connecting plates (1) together.

Fig. 5 shows an exemplary embodiment of the invention, wherein the grooved protrusion (3) is on the left and the locking pin (7) is on the right.

In the present disclosure, the preferred embodiments of the invention have been shown and described and various alternatives and modifications are proposed, but it will be understood that these are not intended to be exhaustive and that other changes and modifications may be made within the scope of the invention. These suggestions are chosen and included herein for purposes of illustration so that others skilled in the art will fully understand the invention and its principles and be able to make modifications as may be best suited to the particular use contemplated.

Claim (modification according to treaty 19)

1. A pile mechanical joint, characterized by comprising one or more grooved protrusions (3) with bolt bases or bars and their corresponding one or more threaded holes (2) in the connection plate (1) of the pile; one or more accommodation chambers (4); one or more milling grooves or slots (6) in the connection plate (1) of the pile and its corresponding cross section may be one or more locking pins (7) of any shape, wherein the shape of the grooves in the one or more grooved protrusions (3) should depend on the cross sectional shape of the one or more locking pins (7), characterized in that the one or more grooved protrusions (3) are in partial contact with the surface of the one or more locking pins (7), whereby such a discontinuous manner allows the one or more grooved protrusions (3) to have a certain flex, as the one or more grooved protrusions (3) only partly surround the circumference of the one or more locking pins (7), for easy insertion of the one or more locking pins (7).

2. A pile mechanical joint according to claim 1, wherein the one or more slotted protrusions (3) in contact with a small portion of the one or more locking pins (7) facilitate the mounting of the one or more locking pins (7) due to the one or more slotted protrusions (3) being in contact with a small portion of the one or more locking pins (7), thereby facilitating the mounting of the one or more locking pins (7) even when the locking mechanism is contaminated by common debris introduced during the piling phase.

3. Pile mechanical joint according to claim 1, wherein the one or more grooved protrusions (3) are machined with precision a bolt seat or shank that is screwed to the threaded hole (2) of the connection plate (1) and the protrusion of the head of the one or more grooved protrusions (3) from the connection plate (1) is made accurate, ensuring accurate operating tolerances (ease of installation of the one or more locking pins (7) even if the connection plate (1) is slightly deformed, damaged and/or manufacturing tolerances are not accurate.

4. A pile mechanical joint according to claim 1, wherein one end of the one or more grooved protrusions (3) is threaded and the other end is provided with a grooved protrusion head (3) when manufactured separately from the connecting plate (1), such that when the one or more locking pins (7) are mounted, the locking mechanism will be further tightened due to the movement of the one or more locking pins (7) and the frictional contact created between the one or more locking pins (7) and the one or more grooved protrusions (3) causing the one or more grooved protrusions (3) to rotate.

5. A pile mechanical joint according to claim 1, wherein the one or more grooved protrusions (3) are threaded at one end and a grooved protrusion head (3) at the other end when manufactured separately from the connection plate (1), which one or more grooved protrusions (3) will allow some bending or lateral movement in the one or more grooved protrusions (3) due to lack of welding to the connection plate (1), thus making the one or more locking pins (7) easy to install.

6. A pile mechanical joint according to claim 1, wherein the two opposing webs (1) are prevented from separating by wedging the one or more locking pins (7) in place between the one or more grooved protrusions (3).

7. A pile mechanical joint according to claim 1, wherein any tensile load is transferred between the two opposing grooved protrusions (3) by wedging the one or more locking pins (7) in place between the grooved protrusions (3).

8. A pile mechanical joint according to claim 1, wherein, when the pile mechanical joint is fully assembled, the milled or slotted holes (6) for the one or more locking pins (7) of the top and bottom connection plates (1, 1) will form a complete channel for the one or more locking pins (7) to contact the one or more slotted protrusions (3).

9. A pile mechanical joint according to claim 1, wherein the pile mechanical joint locking mechanism comprises one or more grooved protrusions (3), milled grooves or slots (6) and one or more receiving cavities (4) which are open or exposed in nature, thus facilitating the removal of debris and the visual inspection of any possible physical obstacle to the successful installation of one or more locking pins (7).

10. A pile mechanical joint according to claim 1, wherein a lip for placing the one or more grooved protrusions (3) is formed on the one or more receiving cavities (4) by using a T-groove side mill to increase the locking strength.

11. A method of joining segmented piles together with a pile mechanical joint comprising one or more grooved protrusions (3) for locking the mechanical joint when mounting its corresponding one or more locking pins (7), wherein the connecting plate (1) is provided with one or more grooved protrusions (3) machined, the one or more grooved protrusions (3) being precision machined into a bolt base or shank screwed into a threaded hole (2) of the connecting plate (1), and with milling grooves or slots (6) for the corresponding one or more locking pins (7), and one or more receiving cavities (4):

(i) -placing together the top piles (5) and the bottom piles (8) with one or more grooved protrusions (3) fully assembled in respective threaded holes (2) so that the connection plates (1) are in contact;

(ii) -placing the one or more locking pins (7) into a channel formed by the milling groove or slot (6);

(iii) When the one or more locking pins (7) are fully installed or hammered in, the whole process is completed.

Claims

1. A pile mechanical joint, characterized by comprising one or more grooved protrusions (protuberants) (3) with bolt bases or bars and their corresponding one or more threaded holes (2) in a connecting plate (1) of the pile; one or more accommodation chambers (4); one or more milling grooves or slots (6) in the connection plate (1) of the pile and its corresponding cross section may be one or more locking pins (7) of any shape, wherein the shape of the grooves in the one or more grooved protrusions (3) should depend on the cross sectional shape of the one or more locking pins (7), characterized in that the one or more grooved protrusions (3) are in partial contact with the surface of the one or more locking pins (7), whereby such a discontinuous manner allows the one or more grooved protrusions (3) to have a certain flex, as the one or more grooved protrusions (3) only partly surround the circumference of the one or more locking pins (7), for easy insertion of the one or more locking pins (7).