GB2160252A - Expansible stud for stud chain links - Google Patents

Abstract

A stud for stud chain links comprises two parts (5,6) movable from an initial position in which they are close to each other and in which the stud is insertable between the two longitudinal legs 3 of a non-yielding link 2, to a position of use in which said parts are spaced from each other and, by means of a pressing member (7), are clamped between said legs. Member 7 is preferably a double threaded stud which effects separation and clamping of the parts. Alternatively it may be a wedge. <IMAGE>

Description

SPECIFICATION Stud for stud chain links Many types of chains, especially anchor chains, are provided with so-called studs or supports, on one hand to prevent the chain from forming kinks, on the other hand to increase its strength. Such a stud is a metal cross-member which is inserted in the middle of each link between the two cross-sectionally circular longitudinal legs thereof and which at its opposite ends has concave surfaces to engage with the round insides of the longitudinal legs. To manufacture a stud chain, a link-forming blank in the form of a steel bar is heated to a red-hot plastically workable state in which it is bent and hooked to the preceding link, and then the flat end surfaces of the bar are joined in a flash welding machine.

While the link thus shaped is still red-hot and workable, the stud is inserted between the still relatively widely spaced-apart longitudinal legs which are then, in a special pressing device, pressed against the opposite concave ends of the stud to secure the stud in position. After formation of the chain in this forming station, it is first conveyed to a hardening station in which it is subjected to a number of hardening and normalising operations, and then to a testing station for tensile testing and inspection.

During inspection, it sometimes happens that studs are discovered which in one way or another are defective, for example cracked.

When this happens, at least parts of the chain must be taken back to the forming station for exchange of both the defective stud and the associated link. Since the length of the chain frequently amounts to one or more kilometres and the weight amounts to several hundred kilograms per metre, taking the chain back to the forming station (and then once again back to the testing station) is extremely time-consuming and costly.

It is the object of the present invention to eliminate the above-mentioned disadvantages and create opportunities for easy and quick exchange of defective studs for stud chain links.

The present invention provides a stud which comprises two halves or parts movable from an intitial position in which they are close to each other and in which the stud is insertable between the two longitudinal legs of a nonyielding link, to a position of use in which said halves or parts are spaced from each other and, by means of a pressing member, are clamped between said legs.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a lateral view of a stud inserted in a chain link and shown in a position of use; Figure 2 is a similar lateral view illustrating the stud in an initial position; Figure 3 is an exploded view showing the components of the stud; Figure 4 is a perspective view showing the stud in the assembled state; Figure 5 is a further perspective view illustrating the stud in its state of use; Figure 6 is a cross-section showing an alternative embodiment of the stud according to the invention; Figure 7 is a cross-section on iine VII-VII in Fig. 6; and Figure 8 is a perspective view illustrating two washer parts included in the stud according to Figs. 6 and 7.

The stud shown in Figs. 1-5 and generally designated 1 is, as appears from Figs. 1 and 2, adapted to be mounted in known manner in approximately the middle of a chain link 2 which besides two U-shaped end portions has two longitudinal legs 3, 3' of circular crosssection. As is best shown in Fig. 4, the stud 1 has at its two opposite ends surfaces 4 which are concavely formed, preferably in the way as described in US patent specification 4,036,010.

In accordance with the principle of the invention, the stud 1 is divided into two separate, but interconnected parts 5, 6 movable from an initial position in which they are close to each other, according to Fig. 2, to a position of use in which said parts are spaced from each other, according to Fig. 1, and, by means of a pressing member, are clamped between the legs 3, 3'. In the embodiment shown in Figs. 1-5, a pin 7 (see Fig. 3) serves as a pressing member and has two threads 8, 9, i.e. a left-hand thread at one end and a right-hand thread at the opposite end, a hexagonal or otherwise polygonal collar 10 being arranged between the two threads for engagement by a tool for rotating the pin.

In the assembled state (see Figs. 1 and 4) of the stud, the external thread 8 engages with a corresponding internal thread 11 in a recess 1 2 in the stud half 5, while the thread 9, by analogy, engages with an internal thread 1 3 in a recess 14 in the stud half 6.

Fig. 3 shows how each of the two stud halves 5, 6 at its inwardly facing end has a circumferential shoulder 1 5 for cooperation with two generally U-shaped parts or plates 16, 16' (see Fig. 5).

If a defective stud of conventional type is discovered in a chain, it is removed from its link (for example by torch cutting) and replaced by a stud of the-type described. In an initial position, the two stud halves 5, 6 of the link are screwed down such that the pin 7 abuts the bottoms in the recesses 12, 14, whereby the two halves approach each other as much as possible and the stud is given its shortest possible total length. In this state, the stud can be inserted between the two longitudinal legs 3, 3' of the link 2, as shown in Fig.

2. in the next step, the pin 7 rotated by means of a wrench or like tool which is applied to the collar 10. Via the two different thread connections 8, 11 and 9, 13, the rotating movement of the pin provides for a longitudinal displacement of the stud halves 5, 6 in a direction away from each other such that, finally, their end surfaces 4 engage with the insides of the legs 3, 3' while clamping the stud therebetween. By appropriate selection of the type of thread and pitch, the force clamping the stud can be made very large such that the stud with full reliability can be clamped in the required position between said legs.Then the two U-shaped plates 16, 16' are mounted in that they are inserted from opposite sides into the space formed between the inwardly facing ends of the stud halves 5, 6, and then the plates are fixed by means of welds 1 7 in the manner shown in Fig. 5.

Before that, the pin 7 may optionally be fixed relatively of the stud halves 5, 6 by means of one or more welds.

In actual practice, the two plates 16, 16' have two functions, i.e. on one hand to conceal the portion of the pin 7 released during the clamping operation and, on the other hand, to reinforce the stud in its entirety.

In the alternative embodiment shown in Figs. 6-8, a wedge 7' is adapted to serve as a pressing member for the two stud halves or parts 5', 6'. In this case, one stud half 6' has a male pin 1 8 which is inserted into and guided by a corresponding female socket 1 9 in the other stud half 5', the wedge 7' being located between the end of the pin 1 8 and a bottom 20, defining the socket 1 9, of the stud half 5'. More precisely, the wedge 7' protrudes through two through holes 21, 21' in the shell-shaped or cylindrical wall 22 embracing the socket 1 9. Furthermore, the wedge 7' is guided in grooves 23 and 24 formed in, respectively, the end portion of the pin 7 and the inwardly facing side of the bottom portion 20.The stud described comprises also two preferably bevelled U-pieces 25, 25' similar to the previously described Uplates 16, 16'. As appears from Fig. 7, the wedge 7' is contemplated to have an initial length which is considerably greater than the width or thickness of the stud.

On application of the described stud between the two longitudinal legs of a chain link, the two halves 5', 6' are brought to a position close to each other, both the wedge 7' and the-U-pieces 25, 25' being removed.

Then the pin 1 8 abuts the bottom in the socket 19, the stud this being given its smallest possible total length. In this state, the stud can be freely inserted between the legs.

Then the two stud halves are separated from each other, and the wedge 7' is driven in to the position shown in Fig. 7, thus clamping the stud between the two longitudinal legs of the link. In a final step, the protruding ends of the wedge are cut off and, besides, the wedge as well as the two U-pieces 25, 25' are welded in the positions shown in the drawing.

By means of the invention, a defective stud can be exchanged without necessitating the return, in a complicated and costly manner, of the entire chain or parts thereof from the testing station to the forming station, as has previously been required.

The invention is, of course, not limited to the embodiments described above and shown in the drawings. Thus, it is possible to use optional types of pressing members, other than screws or wedges, to provide the necessary clamping of the stud. Instead of a double-threaded pin of the type as shown-in Figs.

1-5, a rotatable pin may be used which at one end has a thread, but which at the other end is smooth and engages with a correspondingly smooth recess in the corresponding stud half. Also other modifications are possible within the scope of the appended claims.

The stud according to the present invention can be used not only in the manufacture of chains, but also to repair old or used chains with defective studs.

Claims (9)

1. A stud for stud chain links, comprising two halves or parts movable from an initial position, in which they are close to each other and in which the stud is insertable between the two longitudinal legs of a non-yielding link, to a position of use, in which the halves or parts are spaced from each other, and, by means of a pressing member, are clampable between the said legs.

2. A stud as claimed in claim 1, in which the pressing member comprises a rotatable pin located between the two stud halves and having at least one external thread which engages with a corresponding internal thread in a recess in one stud half.

3. A stud as claimed in claim 2, in which the pin has two threads that is to say a lefthand thread at one end and a right-hand thread at the opposite end, both stud halves have recesses with internal threads corresponding to the two external threads of the pin.

4. A stud as claimed in claim 2 or 3, in which the pin has a polygonal collar or other means for engagement by a tool for rotating the pin.

5. A stud as claimed in claim 1, in which the pressing member comprises at least one wedge.

6. A stud as claimed in claim 5, in which one stud half has a male pin which is inserted into and guided by a corresponding female socket in the other stud half, and the wedge is located between the end of the pin and the base of the socket and protrudes through at least one transverse hole in a wall delimiting the socket.

7. A stud as claimed in claim 6, in which the wedge is guided in grooves both in the end of the pin and in the base of the socket.

8. A stud as claimed in any preceding claim, including, for concealing the pressing member in the state of use of the stud, two Upieces which are insertable from opposite sides into a space between the stud halves.

9. A stud substantially as described with reference to, and as shown in, Figs. 1 to 5 or Figs. 6 to 8 of the accompanying drawings.