FR2640251A1 - SQUARED BASE BODY FOR MULTI-JAWER BURNER JAW - Google Patents

Abstract

The invention relates to a sickle-shaped base body for the jaw of a multi-jaw clamshell which is provided at its upper part with a bore for accommodating the jaw support and below that. here, at the upper part of its external or convex side, a bore for the articulation of the piston rod of a hydraulic cylinder and at the concave internal side of which the jaw plates can be welded. According to the invention, the base body 1 is formed in one piece of cast steel and has a U-profile with branches 2 directed inward. The invention applies in particular to clamshells for the transshipment of materials that are difficult to grasp.

Description

The present invention relates to a sickle-shaped basic body for

  a jaw of a multi-jaw grab that is provided at its upper end with a bore for housing on and below the jaw support at the top of its convex outer side , a bore for the articulation of the piston rod of a hydraulic cylinder and at its concave internal sides

  can be welded jaw plates.

  Multi-jaw grabs are usually used for the transshipment of hard-to-grab materials such as stones, pebbles or scrap, which, for the most part, also have highly abrasive properties. According to the special mode of use, the five usual jaws of a multi-jaw clamshell form, in their closed state, in which at least the tips of the jaws contact or almost touch each other, a container which can be

  open, half closed or closed between the jaws.

  known jaw bodies of the type indicated above usually consisting of a welded construction with a box profile. For the manufacture of this jaw base body is welded two plates parallel to each other, sickle-shaped, forming the side walls at their inner and outer edges to corresponding curved caps. At the free end of the box profile is then inserted a tooth which is also welded, by a continuous weld, to the front edge of the base body profile consisting of a welded construction. Depending on the method of use, base bodies are then provided with sheets welded to their

internal sides.

  Known multi-jaw grabs have, because of the box-type welded construction of their basic body, not only a significant dead weight but also wear-out because the walls of the welded construction are at the base of identical thickness and the convex inner walls of the base body are subject to particularly high wear, so the multi-jaw grab becomes unusable when the outer sides are totally worn although the other parts of the box-like profile

  present in themselves a sufficient resistance.

  The welds of least resistance are particularly susceptible to wear, which means that the multi-jaw grab is already unusable before the outer walls of the base body are worn out. The known basic bodies possess, in addition to their tendency to wear, because of their minimal wear volume in the critical zone, a low structural strength due to the welded construction. In fact, the welded constructions have, in addition to the least resistance of the welds, inevitable internal stresses and undergo, due to the unavoidable effects of notching, an amplified corrosion. Finally, the box shape of the base body profile also leads to higher resistance to penetration when closing the multi-jaw grab. All of these disadvantages are related to high manufacturing prices, which are due to the construction

welded.

  It is therefore an object of the present invention to provide a jaw base body for a multi-jaw grab that can be manufactured with high strength and low weight in a cost-effective manner. According to the invention, this task is solved, in the case of a jaw base body of the type indicated above, in that this base body is formed in a molded steel piece and has a U-shaped profile. with branches pointing inwards. The basic jaw body according to the invention can be

  manufactured economically as a molded steel part.

  This molded steel part has, due to its U-shaped profile, a high structural strength which is due to the favorable moment of geometrical inertia of the profile and the lack of welding. The basic body according to the invention can in principle be used for the various embodiments of multi-jaw clamshells, in that it is sufficient to weld jaw plates of various configurations to its inwardly facing branches. . The basic body according to the invention represents, as a molded part, a monobloc for better arrangement and manufacture of the various variants of a multiple grab bucket

jaws.

  In addition to the considerably lower cost of manufacturing the molded part vis-à-vis a base body which consists of a welded construction, the weight of the basic body according to the invention is also lower because of the profiling and use

optimal material.

  Usefully, the back located on the outside, connecting the branches directed towards the inside of the molded section, is rounded. This form of the basic body leads not only to a decrease in resistance to penetration but also to a lesser attack by

erosion of abrasive materials.

  The wear resistance of the basic body according to the invention can be further increased by the fact that the wear volume in the critical zone is increased. This is why, usefully, the profile of the basic body is made to a greater thickness, at least to its zone

  lower on the back area connecting the branches.

  So, overall, the basic body according to the invention leads, with a lighter construction and lower manufacturing costs, to a greater strength and a longer life due to

its slightest tendency to wear.

  The invention will be better understood, and other purposes, features, details and advantages thereof

  will become clearer during the description

  explanatory text which will follow with reference to the accompanying schematic drawings given solely by way of example illustrating an embodiment of the invention, and in which: - Figure 1 shows a side view of the molded steel jaw base body; FIG. 2 is a sectional view through the base body taken along line A-A of FIG. 1; - Figure 3 is a sectional view through the base body made along the line B-B of Figure 1, in enlarged representation; Fig. 4 is a sectional view through the base body taken along line C-C of Fig. 1; FIG. 5 is a sectional view taken through the base body along line D-D of FIG. 1; and - Figure 6 is a basic body view in

  the direction of the arrow Z in FIG.

  The sickle-shaped base body 1 of a jaw of a multi-jaw grab bucket is made of cast steel and has a U-shaped profile between its upper and lower ends with branches 2 pointing towards the interior which are connected to each other by a rounded back 3 directed outwards. The height of the branches of the profile is adapted to the curve of the bending moment on the base body. The edges of the inwardly directed limbs 2 are bevelled outwardly, as can be seen in the drawing, which favors the junction weld with the jaw plates. The groove or groove formed between the limbs 2 of the profile is closed, at the upper end of the base body 1, by the transverse pad 4 formed in one piece with the profile. The branches 6, joined by the cast iron, pass adjacent to this pad 4, on the right zone of the base body i on its rear side 2, which have a substantially triangular shape and have, in the area of their upper tip, thickenings. 7 which are traversed by aligned holes 8 which form the housing holes for the connection of the rod of

  piston of the closing and opening cylinder.

R E V E ND I C AT I 0 N S

  A sickle base body of a jaw for a multi-jaw grab that is provided at its upper end with a bore for housing on and below the jaw support, at the upper part of its convex outer side, a bore for the piston rod of a hydraulic cylinder and to the inner side of which can be welded jaw plates, characterized in that the base body (1) is formed in one piece made of cast steel and has a U-shaped profile with branches (2)

directed inward.

  Base body according to claim 1, characterized in that the outwardly directed back (3), which connects the branches (2) directed towards the inside of the

molded profile, is rounded.

  3. Basic body according to any one of

  1 or 2, characterized in that the profile of the

  base body (1) is formed with a greater wall thickness at least at its lower zone, on the

  rounded back area (3) connecting the branches (2).