EP0017674B1

EP0017674B1 - Apparatus for twisting together the end portions of wire around a bundle

Info

Publication number: EP0017674B1
Application number: EP19790200178
Authority: EP
Inventors: Jan Middel; Hendrik Franke
Original assignee: Hoogovens Groep BV
Current assignee: Tata Steel Ijmuiden BV
Priority date: 1979-04-11
Filing date: 1979-04-11
Publication date: 1983-09-28
Also published as: EP0017674A1; DE2966216D1

Description

This invention relates to apparatus for twisting together the end portions of wire around a bundle, so as to form a twist knot securing the wire, comprising a rotatable head, means for rotating the head about a vertical axis, and a pair of arms each having a first end pivotally mounted on said head so that the second end is movable towards and away from said axis, there being a slot in said second end of each arm to receive the wire, wherein said slots respectively receive the ends of the wire in the open position of said arms, and said arms are closed together as the head is rotated so as to twist the ends of the wire together, said arms are pivotally mounted on horizontal axes so as to be capable of free uncontrolled movement inwardly towards the vertical axis whereby the arms are pulled inwardly by the wire when the head rotates to form the knot, means being provided for drawing the wire around the bundle from a continuous stock of wire and means for cutting off the length of wire extending around the bundle after the wire has been drawn.
Such apparatus is known by the U.S. patent specification 1 684 723 in the form of a portable binding tool for twisting the free ends of a piece of binding wire, which has been passed around two crossing reinforcing rods at their cross-over points.
Bundling machinery is used in rod and wire mills, and a bundle in this connection is a number of mostly parallel rods or wires, fastened together into a mass convenient for handling or conveyance. In a mill there is small bundling equipment for bundling a number of rods, together with a counting device for rods and so-called large bundling equipment for bundling a number of small bundles of rods, together with a counting device for the small bundles.
To secure the bundles, wire lengths are passed circumferentially around them, and are knotted at the free ends. This knotting operation is still usually performed manually; it is strenuous work and, with for instance wire of 5 mm diameter, means that the wire must previously be annealed in order to render it soft enough to be manipulated. The annealing of the wire increases its cost.
German patent specification No. 310 265 discloses a stationary device in a rod and wire mill wherein the pivoted arms are moved, in their open position, so as to embrace the bundle with their ends projecting beyond the bundle whereupon a straight and already cut length of wire is passed through the specially shaped slots in the ends of the arms. The arms are then withdrawn past the bundle so that the wire is bent and lies alongside three sides of the bundle, then the arms are pivoted so that their ends move together to bring the wire ends together, this being a positive action effected by moving guide slots acting on pins on the arms, and the head carrying the arms is rotated to through 180° to twist the wire ends round each other.
The known apparatus has two particular disadvantages. Firstly, it is complicated, since complex means for controlling the movement of the arms is necessary. Secondly, automatic adaptation to different bundle sizes is not possible, because the wire is cut to length before being wrapped around the bundle.
The apparatus according to the present invention is a simplification of the apparatus known from said German patent specification, and also provides means for forming a knot which is independent of the means for wrapping the wire around the bundle.
The apparatus for twisting together the end portions of wire around the bundle according to the present invention is characterized in that the arms are freely pivoted on the said horizontal axes and are biased outwardly by gravity, during the rotating movement of the arms the binding wire slips through the slots and in their closed position the arms provide a central space which is preferably cylindrical and in which the knot is formed and in that an axially extending spigot with a conical extremity is located in said central space, the knot being formed by winding the end portions of the wire around the spigot and its conical extremity.
As the rotation is about a vertical axis, the bias is provided to return the arms to the open position after the knot is formed.
It is to be remarked that U.S. patent specification 4 117 872 describes also a portable binding tool for twisting the free ends of a binding wire, particularly for holding together metal reinforcing rods at their cross-over points, in which during the rotating movement of the components 36 the binding wire also slips through the receiving passageways 34a, 34b.
The slots in the arms are shaped so as to clamp the wire automatically when the head begins to rotate.
The apparatus according to the invention is used with separate means for wrapping the wire around the bundle and cutting it to length afterwards; thus the length of the wire can be adapted in each case to the bundle size. The head can perform as many rotations as is desired, in fact until the wire ends are pulled out of the slots in the arms into the knot (compare the 180° turn only of the old proposal of the German patent specification discussed above). Thicker wire (e.g. 6 mm) than is used for manual knotting can be used, providing a stronger knot, and prior annealing is not required.
By the invention it is possible to provide devices which can be universal for all types of arrangements e.g. semi-automatic bundling, small bundle, single wire, single twist up to fully automatic bundling, vertical set-up, double wire, double twist.
The principle underlying the invention and one practical embodiment constructed in accordance therewith will be described below with reference to the drawings, in which

Figs. 1 a, 1 b and 1 c show stages in the operation of a simplified device falling outside the scope of the claim but helping to explain the invention, here illustrated diagrammatically, and shown forming a twist knot in a U-shaped bent wire previously applied to a small bundle of bars;
Fig. 2 is a perspective view of the arms of the practical embodiment of the device of the invention in their open position;
Fig. 3 is a perspective view of the device of Fig. 2 with the arms in their closed position; and Fig. 4 is a perspective view of the knot formed by the device of Figs. 2 and 3.

Fig. 1 a shows a bundle of bar material 1, preformed by means of a trough (not shown), and having around it a U-shaped previously bent bundling wire 2 which has been applied either manually or by means of a machine (not shown), which pulls the wire from a store around the bundle and then cuts the wire at the appropriate point. A rotatable head 3 is mounted on a holder 8, which can be rotated round its vertical axis 9 by means of a motor (not shown). The head 3 carries two jaws or arms 4 which at one end are mounted pivotally on the head 3 in such a way that their outer ends can move freely towards and away from the axis 9. The two arms 4 are, in this case, identical and are mounted 180° apart around the axis 9. At their outer ends the arms 4 are provided in one face with a throat-shaped slot 6. Fig. 1 a shows the ends 7 of the U-shaped wire length 2 inserted e.g. by hand in the slots 6.
The wire length 2 is slightly wider than the actual bundle diameter, so that the ends 7 can be inserted easily into·the slots 6.
When the head 3 is rotated, the wire ends 7 become tightly held in the slots 6, so that both arms 4 pivot towards the axis 9 during the initial rotation through 180° in which the wire ends 7 come into the position shown in Fig. 1 b. In this position the bundling wire 2 lies stretched around the bundle 1.
Further turning of the head 3 causes the ends 7 of the bundling wire 2 to be completely twisted together, the ends 7 being dragged through the slots 6 as they are formed into the twist knot (see Fig. 1 c). When these ends emerge from the slots, the arms 4 return to their open starting position, pivoting around the pivot points 5 of the arms 4. As the rotatable head is arranged with a vertical axis (9) of rotation, opening of the arms is brought about by the force of gravity. What is important is that the free inward rotating of the arms, pulled by the wire, during the initial period of rotation should not be substantially hindered.
The length of the arms as well as the spacing from the pivot points of the arms to the trough or other support for the bundle should be suitably chosen for each case, and may be calculated in such a way that small as well as large bundles can be handled by a single machine according to the invention.
From Fig. 1 c can be seen that a knot is made in the form of a protruding braid. A flatter knot can be obtained however by using the proper embodiment of the invention to be described now.
Figs. 2 and 3 show a more developed form of rotating twis: head forming part of apparatus embodying the invention. The two arms 100, 101 which are mounted on the rotating head 102 by pivots 103 each have two parallel flanks 104 joined at their free ends 105 by identical shaped metal blocks 106. These blocks 106 have flat inner faces 107 which mutually abut in the closed position of the arms 100, 101 (Fig. 3) and which have central axially extending grooves 108. Also mounted on the head 102 is an axial column 109 carrying an axial spigot 110 which lies in the grooves 108 in the closed position when conical extremity 111 of the spigot 110 projects into a cylindrical space 112 provided between the blocks 106 by semicylindrical recesses 113 beyond the flat faces 107. The rear wall of each recess 113 is open to a slot 114 which is partly overhung by a triangular flange 115. Outwardly projecting lugs 116 of each block 106 provide the outwardly diverging sides of each slot 114.
The slots 114 do not reach the inner faces 107.
In operation the wire ends are brought manually or automatically into the slots 114, before the head is rotated. Upon rotation, the wires are caught by the blocks 106, particularly by the flanges 115, so that the wire ends become twisted first around each other and later around the spigot 110. The cylindrical space 112 provides room for the twists of the knot to collect. When the wire ends have entirely been absorbed into the knot sufficiently to come free of the slots 114, the arms 100, 101 are released, and fall apart under the action of gravity.
The knot so formed is seen in perspective in Fig. 4. Part of the length extending around the bundle is shown at 120. Adjacent this is a portion 121 where the wire is tightly twisted, while closer to the free ends 122 of the wire are the more open twists 123 formed around the spigot 110.

Claims

Apparatus for twisting together the end portions (7) of wire (2) around a bundle (1) so as to form a twist knot securing the wire, comprising a rotatable head (3; 102), means for rotating the head about a vertical axis (9) and a pair of arms (4; 100, 101), each having a first end pivotally mounted (5; 103) on said head (3; 102) so that the second end is movable towards and away from said axis, there being a slot (6; 114) in said second end of each arm to receive the wire, wherein said slots respectively receive the ends of the wire in the open position of said arms and said arms are closed together as the head is rotated so as to twist the ends of the wire together, said arms are pivotally mounted on horizontal axes (5; 103) so as to be capable of free uncontrolled movement inwardly towards the vertical axis (9) whereby the arms are pulled inwardly by the wire when the head rotates to form the knot, means being provided for drawing the wire around the bundle from a continuous stock of wire and means for cutting off the length of wire extending around the bundle after the wire has been drawn, characterised in that the arms (4; 100, 101) are freely pivoted on the said horizontal axes (5; 103) and are biased outwardly by gravity, during the rotating movement of the arms (4; 100, 101) the binding wire (2) slips through the slots (6; 114) and in their closed position the arms (100, 101) provide a central space (112) which is preferably cylindrical and in which the knot is formed and In that an axially extending spigot (110) with a conical extremity (111) is located in said central space (112), the knot being formed by winding the end portions of the wire around the spigot (110) and its conical extremity (111).