The invention relates to a jig for use in bending ship's frame sections.

In bending steel profiles into frame sections for ships by hand or semi- automatically on a bending machine, an elongated jig is always used, which shows the wanted curved course of a frame section. Said jig is placed contra to the still straight profile and the course of the jig's edge is transferred on the still straight profile with chalk. During the step by step bending the chalk line obtains a straight course.

The jigs are obtained by drawing the wanted shape in real size on a plate or on foil and to place steel rods along it, which rods each form a part of the jig, and to hammer them into shape. The rods are then used one after the other and partly in an overlapping manner when bending the rib. After bending the portion which corresponds to a jig part a check takes place for in principe that portion by placing it on said plate or foil. After the entire profile has been bent, the total shape is checked by placing it on the plate or foil.

The transitions from the one jig part to the other jig part require close attention of the personnel to ensure that the bending line is not locally buckled or displaced, putting the quality of the whole directly at stake.

This manner of working moreover requires a lot of expensive material and effort, whereas moreover the floor is taken up by the plate and the people involved are physically very heavily burdened.

An object of the invention is to improve on this. To that end a jig is provided for use in forming frame sections by bending, the jig being elongated and consisting of a number of parts, which at the location of the complementary connection ends can be laid in line with each other, the complementary connection ends of the jig parts having aligning and placement means which engage each other in a confining manner.

The jig according to the invention has a functionality both in the separate jig parts (the bending itself) and in the entirety (after the bending of a frame section) : in the first case guiding and marking off during processing and in the second case the final check of the entire final shape of the bent frame section.

Preferably the aligning and placement means comprise coupling means, to increase the rigidity of the engagement.

Preferably the complementary connection ends have end edges extending from the one longitudinal edge of the jig to the other longitudinal edge of the jig according to a line, with in it at least a bulge and a receiving space complementary to it, respectively.

Preferably the end edges comprise a middle portion extending substantially in longitudinal direction of the jig between a first transverse portion, contiguous to the one longitudinal edge and a second transverse portion contiguous to the other longitudinal edge, at least two of the aforemen- tioned portions of the end edges being provided with complementary bulge and receiving space.

Preferably the middle portion is provided with a complementary bulge and receiving space.

Preferably the end edges are provided with complementary bulge and receiving space at at least two locations spaced apart in longitudinal direction. In this way the connection is made more rigid against bending movement in the plane of the jig.

When the bulge is substantially hook-shaped, the rigidity of the connection is further increased.

Preferably a receiving space is formed adjacent to the bulge on the one end edge for a complementary shaped bulge on the other end edge, so that the connection means engage into each other over a large edge length and in several directions.

If the jig has at least a receiving space with a portion which in transverse direction is limited in two opposing directions by the end edge concerned, a large certainty of placement and aligning in transverse direction is obtained.

If the jig has at least a receiving space with a portion which in longitudinal direction is limited in two opposing directions by the end edge concerned, a large certainty of placement in longitudinal direction is obtained.

It is advantageous here when said receiving space is situated in the middle portion, as a result of which tensile forces in longitudinal direction can be transferred without displacement of the jig parts.

It is furthermore advantageous here when said receiving space is situated in the first and/or second transverse portion, as a result of which pressure forces in longitudinal direction can be transferred.

By using a tensionless material that can be machined for making the jig

parts, such as for instance MDF plate, a correct engagement of the connection means is guaranteed. MDF plate material is moreover easy to handle and cheap. From one plate many jigs can be made.

The invention will now be elucidated on the basis of an exemplary em- bodiment shown in the attached drawing, in which : Figure 1 shows three jig parts in separate situation, which together can form a jig according to the invention ; Figure 2 shows the jig parts of figure 1 in assembled situation ; Figure 3 shows detail III of figure 2 ; and Figure 4 shows detail IV of figure 2.

In figure 1 three jig parts 1,2 and 3 are shown. Said jig parts 1,2 and 3 are made from MDF plate, accurately cut or milled from it via a CNC controlled machine according to a pre-calculated line, which as concerns one of the longitudinal edges exactly corresponds to the wanted bending line of the frame section profile to be bent with the help of the jig. The jig part 1 and the jig part 3 at one end are provided with an end edge 4 and 7, respectively, and the jig part 2 is provided with end edges 5 and 6 on both ends, the end edges 4-7 being formed in a special manner.

The end edges 4-7 namely do not only comprise a number of stretched portions, but also three hook-shaped lockings 4a-c, 5a-c, 6a-c and 7a-c, which are spaced apart in longitudinal direction. These lockings are milled in exactly the wanted shape, comparable to a jig-saw puzzle. They are formed such that lockings 4a, 5a, 4b, 5b and 4c, 5c fit exactly into each other, and the same goes for locking 6a, 7a, 6b, 7b and 6c, 7c. It is

ensured however that the locking 4a-4c cannot cooperate with the loc- kings 7a-7c by making the interspacings different, so that incorrect succes- sion of the jig parts is ruled out.

When the jig parts 1,2 and 3 are fitted into each other, they form a jig 10, which in this case has an inner edge, which follows exactly the wanted course of the frame section profile to the bent. Mutual displacement in longitudinal direction of the jig parts 1,2 or 3 or rotation at the location of the connection places is as good as ruled out with normal loads during work and do not lead to unacceptable deviations. The rotation is mainly counteracted by arranging several lockings spaced in longitudinal direction, for instance 4a, 5a, 4b, 5b and 4c, 5c.

As shown in figure 3, locking 4b is provided with a bulge 4d and an adjacent receiving space 4e. The locking 5b is formed with a receiving space 5d and a bulge 5e. The bulges 4d and 5e are situated mutually offset in transverse direction. When the lockings 4b and 5b engage exactly into each other, as a result a rigid connection is effected against movement caused by tensile forces on the parts 1 and 2 in the directions T.

In a similar manner rigidity against pressure forces D is increased at the location of the other lockings, such as for instance lockings 4c, 5c in figure 4. To that end locking 4c is provided with a receiving space 4f and a bulge 4g situated adjacent to it in longitudinal direction, whereas locking 5c is provided with a receiving space 5g and a bulge 5f situated adjacent to it in longitudinal direction.

The jig parts 1,2 and 3 have manageable lengths, for instance of a little over 2 meters.