1. Device for removing locking pin from chain connecting link, characterized in
i) a shape adapted holding member (10) arranged to accommodate a chain connecting link (1) with an orientation relatively to the holding member (10) determined by the shape of the latter, the holding member (10) having a rotational axis (A) for attachment of a positioning member (20), and
10 ii) a positioning member (20) arranged to be pivotally attached to the holding member (10) about the rotational axis (A) which is arranged to be perpendicular to the axis of a locking pin (4) in a chain connecting link (1) when the holding member (10) holds a chain connecting link (1), as well as
iii) a piston member (24) held by the positioning member (20), said piston member (24) 15 being arranged to be moved linearly by a force from an hydraulic cylinder (25), the piston member (24) being arranged perpendicular to the rotational axis (A).
2. Device as claimed in claim 1, characterized in that the connecting link (1) is a "kenter" type chain connecting link.
3. Device as claimed in claim 1, characterized in that the positioning member (20) is so
: shaped that during use a gap (C) is formed between this and the connecting link (1) in the area in which the piston member (24) meets the locking pin (4) to allow visual control of the positioning of the piston member (24).
4. Device as claimed in claim 1, characterized in that the piston member (24) extends through the hydraulic cylinder (25) to thereby allow the back end thereof to be pounded during use. 0 5. Device as claimed in claim 1, characterized in that the positioning member (20) and holding member (10) are arranged to be hinged together at both sides of the connecting link (1) to thereby ensure a greater degree of stability.
6. Device as claimed in claim 1, characterized in that the hinged connection at one side the connecting link (1) has the form of an "eye" (21) around a pivot (14) and at the opposite side with a lacking dog (17) around an attachment member (22). 7. Device as claimed in claim 1, characterized in that the positioning member (20) mainly has the shape of an arm (23) holding an hydraulic cylinder (), means for the connection of hydraulic pressure to the hydraulic cylinder, a piston member (24) which is linearly movably attached in the hydraulic cylinder (25) and a circular "eye" (21) adapted to be positioned over a cylindrical pivot (14) on the holding member,
The present invention concerns a device for removing locking pins form chain connecting links as defined by the preamble of claim 1.
Background In some connections, especially offshore but also on shore, chains are used to secure or hold heavy cargo, vessels and vessel anchors. Such chains are commonly assembled by short chains to one long chain by means of chain connecting links which has substantially same external shape as a chain element.
Where the chain is dimensioned and shaped to withstand heavy forces, also the chain connecting link must be able to withstand the same forces. With regard to chains especially made for ships, for anchors etc. a certain standardization has taken place. For instance is a type of chain connecting links known as "Kenter" largely used, admittedly with some variations thereof.
The Kenter connecting link is mainly comprised by two U-shaped parts having different leg lengths and thickness for each of the legs, such that when two is faced towards one another, the short leg of one will fit into the long leg of the other, since the long leg is formed with a void dimensioned to receive the thinner, shorter leg. When both respective short legs have been pushed into opposite long legs in such a pair a complete connecting link is formed. To lock the two parts together a metal locking pin is pressed or knocked into for the purpose adapted, aslant openings in the long legs of each element. Thereby the two parts are locked together in a secure manner so long as the locking pin remains in place. Between the long sides of the connecting link there is also solid goods in the form of an intermediate or "bridge" piece that hides and protects the locking pin and which divides the else oblong "eye" of the connecting link into two mainly circular eyes, each adapted to receive a respective chain for joining the two to one.
Other chain connecting links can have a shape that deviates somewhat from the Kenter connecting link, for example links in which the locking pin locking the two parts together is arranged perpendicular to the length axis of the link, not aslant. This is conditional upon the entire connecting link being designed somewhat different. When a chain is pulled up, there is often a need to open the connecting link, that being for replacement, repair or just to.split in into separate short chains. The commonly used way to do this is to place last chain element before or after a connecting link in a so-called shark-mouth on deck, so that this part of the chain is held in place. Then one can use a sledgehammer and mandrel to attempt knocking out the locking pin. This is, however, a heavy, time consuming, very noisy and not least dangerous work task. The environment in which such chains are located and the forces they are exposed to, can lead to the locking pin becoming jammed and very hard to remove. In extreme cases the connecting link may need to be destroyed by a cutting torch. Use of open flames and heat on deck is generally undesirable and labelled as a risk operation.
It is therefore e need to provide equipment which is simpler, faster, less dangerous and less noisy to use for this task. Equipment for such purpose is shown in US patent No. 4,870,739. The equipment according to this patent comprises a hydraulic pump and an assembled unit designed to be bolted around a chain connecting link so that a locking pin arranged perpendicular to the length axis thereof can be forced out. The assembled unit has two long bolts which extend from a first "shoe" so that one bolt can be positioned on each side of the connecting link. At opposite side of the connecting link another shoe is placed and the entire equipment is assembled by tightening nuts fitting threads on each bolt. This equipment provides a much better solution than the sledge but time and tools are required for the assembly. In addition this solution is not suited for Kenter type connecting links in which the locking pin is positioned aslant the length axis of the link. Another disadvantage is that the positioning of the expelling member in relation to the locking pin is difficult because the connection point between the two is hidden by the first shoe.
It is thus an objective of the present invention to provide equipment to open chain connecting links, which is risk free to operate, simple to use, and which can be adapted to different types of connecting links.
It is furthermore an objective that the positioning of the equipment in relation to the relevant connecting link not shall constitute a problem.
The present invention Said objectives are achieved by the device according to the present invention as defined by claim 1. Preferred embodiments of the invention are disclosed by the dependent claims.
It is in this connection referred to the drawings, where:
Fig. la shows a Kenter type connection link in its closed position.
Fig. lb shows a part of a Kenter type connection link. Fig. 2a shows an embodiment of the device holding member according to the invention.
Fig. 2b shows an embodiment of the device positioning member according to the invention.
Fig. 3 shows the device according to Fig. 2a/ 2b in operation.
Figure la shows a Kenter connection link in closet position in which two "halves" 2 and 3 are locket together by means of a locking pin 4. The half 2 has the shape of a letter U with different leg length, having a long leg 2a which is hollow with an internal diameter adapted to the outer diameter of the short leg 2b. The half 3 is similar to half 2. Thereby two halves facing one another can be combined by introduced the short leg 2b into the long leg 3a while the short leg 3b is introduced into the long leg 2a. The long legs 2a, 3a each has an opening for receiving a locking pin 4 which can be introduced by force to prevent the two halves to come apart. In order that the locking pin shall not interfere with the short legs 2b, 3b, it is arranged aslant as shown by figure la.
An intermediate part 5 is shown between 2a and 3a arranged to hide and protect the locking pin in this area and dividing the combined connection link in two mainly circular openings 6 and 7 each suited to receive a respective end link of a chain.
Figure lb shows the half 3 with long leg 3a and short leg 3b. With dotted lines is indicated the opening 8 for a locking pin.
Figure 2a shows the holding member 10 of the present subject matter with a bottom element 11 and a to the bottom element, by the axis 13 pivotally attached top element 12. The top element has a pivot 14 forming an element of an (imaginary) rotation axis A (dotted line) perpendicular to the axis 13. Centering members 15a, 15b are attached to the bottom element 11 and/ or the top element 12 to ensure that a connection link placed in the holding member will have a precisely defined position relative to the holding member. This is also ensured by the fact that the bottom element 11 has a form-fitting inner surface 16 that is carefully adapted to the shape of the Kenter connection link. The inner surface 16 is typically not a continuous surface but a structure consisting of curved ribs with open spaces there between.
Just below the pivot 14 on the top element 12 a locking dog 17 is attached to the bottom element 11. The pivotal point 19 for the locking dog lies in the imaginary axis defined by the pivot 14, when the top element 12 is turned down in the direction towards the bottom element 11. The top element 12 has handles 18 intended to be held by the user.
Figure 2b shows the positioning member 20 being adapted to cooperate with the holding member 10 and together constitute the device according to the present invention. The positioning member has an eye 21 adapted to surround the pivot 14 of the holding member and an attachment member 22 adapted to be engaged by the locking dog 17. Since the pivotal point 19 of the locking dog has common axis with the pivot 14, namely the pivotal axis A, the entire positioning member can be turned in a plane common with (or parallel with) the plane of a Kenter connecting link 1 enveloped by the holding member and the positioning member. In the main body 23 of the positioning member there is an hydraulic cylinder 25 with a piston member 24 which when actuated by the hydraulic cylinder, will protrude from an opening 26 in the main body 23. By designing the hydraulic cylinder 25 with a central passage thorough which the piston member extends, a free end of the piston member may at any time be available at the back (to the left of Figure 2b) thereof, so that the force upon the piston member may be increased by hitting it when already under tension from the hydraulic cylinder. With an arrow and the letter C to the right of the main body 23 is indicated that there will be a clearance between the positioning member and a (Kenter) connecting link positioned in the holding member. It will thus be possible to visually verify that the piston member is correctly positioned in relation to the locking pin before force is applied to the piston member to push out the locking pin. The positioning member 20 is also equipped with handles 27.
Use of the device
The operation sequence for opening of the connecting link is as follows. The chain in question from which a connecting link is to be removed, is arranged in a desired manner, e.g. in a "shark jaw" that is rigidly attached to a ship deck or a dock site onshore, to steadily support the chain. It should however be emphasized that use of the present device does not require that the chain is completely steadily supported. The bottom element 11 of the holding member 10 is pushed onto the connecting link in question from one side while the top element 12 is rotated away from the bottom element at the pivotal axis 13. When the bottom element is correctly positioned in relation to the connecting link, defined by correct contact between the connecting link and the inner surface 16 as well as between connecting link and centering members 15a, 15b, the top element 12 is rotated as far towards the bottom element 11 as possible. Due to the form fitting of the holding member in relation to the connecting link, it is only possible to rotate the top element when the connecting link is correctly positioned in the holding member. Since the locking pin 4 has a thick and a thin end, it is vital that the holding member's 10 inner surface 16 is positioned adjacent the thick end of the locking pin as explained more in detail below.
It is not critical how the holding member is oriented, the bottom member does not have to be positioned below the top element, the elements can be oriented side by side (upright), aslant, or with any other orientation. It does, however, simplify the subsequent mounting of the positioning member if the top element is oriented such that the pivot 14 is facing mainly upwards.
The positioning member 20 is thereafter attached to the holding member by hanging the eye 21 over the pivot 14. Thereafter the locking dog 17 is attached to the attachment member 22. It is actually not a need for the locking dog 17 or the attachment member 22, but the full enclosure of the connecting link between the holding member and the positioning member thereby obtained ensures a stable behavior of the device even when extreme forces is applied from the hydraulic cylinder. In addition the extra fixture by the locking dog contributes to prevent the positioning member to slip off if the orientation is upright or even upside down. When the holding member and positioning member is attached to one another as described, the axis defined by the pivot 14 and the pivotal point 19 is perpendicular to the locking pin in the connecting link in question and the piston member 24 will be in the same plane as the locking pin. By rotating the positioning member about the axis defined by the pivot 14 and the pivotal point 19, the opening 22 is brought to a point just outwards from the locking pin 4, and in this position the piston member 24 will be parallel with - and in line with - the locking pin 4. It is referred to Figure 3 where the end of the piston member 24 is in contact with the thin end of the locking pin 4 and in the process of pushing it out. In Figure 3 most of the holding member 10 is omitted for simplicity's sake, but it shows how the centering members 15a, 15b cooperates in holding the connecting link in a fixed orientation in relation to the device according to the present invention. The rotatability of the positioning member 20 ensures that the correct position can be obtained independent of the orientation of the holding member in relation to the connecting link (except that the side covering the thick end of the locking pin must face towards the surface 16), by rotating the positioning member either to the left or to the right of the centre position for connecting links with aslantly orientated locking pin. In the case of connecting links having the locking pin at a right angle, the positioning member 10 is orientated in its centre position.
In practice the positioning can take place while at the same time starting to move the piston member linearly by means of the hydraulic cylinder 25. As an example a coarse orientation of the positioning member may be performed first. Thereafter the piston member may be moved forward until nearly in contact with the lcoking pin 4 or with the leg 2a or 3a close by the locking pin. Then the positioning member is adjusted again and the piston member 24 moved forward until touching the locking pin 4. If the piston member is not hitting at the center of the end surface of the locking pin 4, a last adjustment of the positioning member is performed before the pressure is increased on the piston member which inexorably pushes out the locking pin. If desired "click stops" may be arranged at certain positions of the positioning member, by means of small recesses in an otherwise circular disc at the back side of the locking dog 17 and a wedge member adapted to the recesses in the bottom element 11 of the holding member 10, the wedge member being pushed into the recesses by a controlled force from a spring. Such click stops can be arranged in a tight pattern or just a few adapted to certain types of connecting links.
A person skilled in the art understands that there are other ways than the one shown to hinge the positioning member pivotally to the holding member and all known ways to accomplish such hinged connection are within the frame of the present invention.
While the holding member must be specially adapted to each type of connecting link for which it is intended, the positioning member may be made in a manner allowing it to cooperate with a number of different holding members, provided there is an axis standardization among the holding members. If a higher degree of versatility is desired, a "universal" holding member may be designed in which a lining chosen among a number of available linings are used together with the holding member, while only the linings are form fitted to the relevant type of connecting link to be opened in each relevant case. By "form fittet" holding member is understood that the holding member can only be attached to the connecting link with one defined orientation. The holding member can thus only be attached to a relevant connecting link when their mutual orientation is entirely "correct", which a.o. means that it is thereby ensured that the angle between the pivotal axis of the holding member and the locking pin in a connecting link held by same, is perpendicular (90 degrees).
The positioning member 20 is arranged to be attached to the holding member 10 when a connecting link is placed within the latter and by rotation the position member 10 can position a piston member 24 against the end of the locking pin 4 in the connecting link. Since the holding member 10 due to its (inner) shape always will have a defined orientation in relation to a binding link on which it is arranged, it is easy to position the piston member 24 correctly by rotating the position member 20, since the piston member is perpendicular to the pivotal axis A and therefore will be parallel with the locking pin 4 when the positioning is correct.
It is furthermore a clear advantage if control of correct positioning can be made visually and it is therefore preferred to let the positioning member have a recess towards the connecting link just for that purpose.