Abstract: The disclosure relates to the production by means of an electrical resistance welding method, of grids formed from metal wires crossing over another. The grid wires are carried through between rows of cooperating electrodes and, under pressure, are welded together at the cross points of the wires by an electric current. Each cross point of the wires and the surfaces of the associated electrodes of the grid welding machine, which lie in the welding region, are subjected to the action of a liquid coolant to increase the life of the electrodes and reduce distortion of the grid due to the localized heating of the wires.

Abstract: A grating of metal longitudinal strips (1) standing on edge in parallel with one another and narrower metal cross-strips (3) parallel with one another, is (for the achievement of higher load capacity) produced in such a way that in the longitudinal strips (1) slots (2) of changing width are incorporated, in which the inside width of the slot at the open end of the slot is chosen to the greater than, but on the contrary remote from this end of the slot is chosen to be less than the thickness of the cross-strips (3), cross-strips (3) are inserted into these slots (2) with the application to the strips (1, 3) of a welding voltage serving for the resistance welding, and with the application of pressure in the direction of insertion, so that material driven out from the edges of the slots forms weld beads (9) at the points of intersection of the strips.

Abstract: A stacking device for wire grids such as those welded grids used for reinforcing concrete, has vertical guides into which the free ends of a selected longitudinal wire of the grid slide so as to form a stack, one grid on top of another. One of the vertical guides can be pivoted out of its vertical position so as to release the stack onto a transporting device for removal.

Abstract: A lattice girder making machine has a stepwise feed mechanism for upper and lower chord wires; and a continuously operating bending mechanism for bending wire into zigzag strutting which is welded to the chord wires at a welding station. Between the bending mechanism ad the welding station the zigzag strutting slides along guides which allow the strutting alternately to contract resiliently and then to expand to accommodate the stepwise advance through the welding station. At the welding station the strutting is held at the required extension by fingers.

Abstract: A double point welding machine has active electrodes (3,4) and passive counter-electrodes (8,9) for simultaneously welding rods (5,6) together. In order to ensure that the welding pressure is uniform at both welding points, the counter-electrodes (8,9) are mounted on a current bridge (7) carried by a pressure beam (15). The pressure beam forms part of a four bar pivotal linkage the other arms of which are formed by rams (26,27) and a second beam (24) which is pivoted at a pivot (25).

Abstract: The invention relates to apparatus for and a method of moving a grid (G) longitudinally in stepwise fashion through a multi-spot welding machine by means of an element (5) arranged to engage a transverse rod (D) of the grid at a starting position, move the grid (G) forward through a number of steps at a first mean speed, and thereafter disengage from the rod (D) and return to the starting position at a mean speed greater than the first mean speed. The movement of the element (5) is controlled by a computer (31) so as to return to its starting position if the time required for its return from the position which it would occupy after the next step is greater than a preset maximum standstill time between steps.

Abstract: The invention concerns a mechanism for transferring cut-to-length wires out of a loose bundle of wires into a single layer of parallel wires. The mechanism comprises a wire channel, for receiving the single layer of parallel wires, which is inclined to the horizontal. The upper end of the lower side of the inclined channel extends beyond the upper end of the upper side to form a rest for the loose bundle of wires. At least one wiper-cam is positioned above the extended end of the lower side of the channel and is pivotable to and fro in the longitudinal direction of the channel, the end face of the cam facing the lower side of the channel being spaced from the lower side by a distance such as to allow a single wire to pass therebeneath into the channel. The lower side of the channel can be moved relative to the upper side of the channel.

Abstract: An alternating voltage amplifier circuit has a plurality of semiconductor amplifier elements, preferably field effect transistors, operated in a grounded gate (base) configuration. The amplification direction is not to be determined until the application of specific operating voltages and is reversible by means of reversing such voltages. At least two semiconductor amplifier elements are provided in parallel to one another. One of the semiconductor amplifier elements is effective in one direction of amplification as an input amplifier and, with the other semiconductor amplifier element, in the other amplification direction has a power amplifier, the other semiconductor amplifier element being connectible or disconnectible upon reversal of the amplification direction.

Abstract: The invention is concerned with an electrical resistance welding machine for producing a wire lattice by welding together longitudinal and transverse wires at their crossover points. The wires are fed stepwise between at least one pair of electrode devices and means synchronized with the feeding means bring the electrode devices together to clamp the wires at one of the crossover points to allow a welding operation to be effected. At least one of the electrode devices comprises a welding electrode in the form of a circularly cylindrical disc which is fitted to an electrode holder and can be rotated to bring new parts of its peripheral surface into the working position. The axis of the disc is inclined at an acute angle to the axial directions of the longitudinal and transverse lattice wires to provide an improved contact surface between the disc electrode and wires, particularly to avoid any tendency of the transverse wires to be displaced laterally by the contact pressure.

Abstract: The invention relates to a change-under-load transmission having an input shaft (1) and an output shaft (6), each carrying a pair of gearwheels (2, 3; 4, 5). A composite layshaft comprises two pairs of coaxial shafts (7, 8; 9, 10) which are aligned axially with one another. At their adjacent ends the shafts carry friction coupling elements (25, 31 and 25, 30) which have effective coupling faces (25', 31'; 26' 30'). At their remote ends each of the coaxial shafts carries a gearwheel (23, 27; 24, 28) which is in permanent mesh with an associated one of the gear wheels on the respective input or output shaft. Between the adjacent ends of the two pairs of coaxial shafts a central friction coupling element (32) is positioned so as to be freely slidable axially with respect to the coaxial shafts. Correspondingly positioned ones (7, 9 in FIG. 1; 8, 10 in FIG.

Abstract: A machine for stacking mesh reinforcement grids alternatingly in initial and reversed orientations includes a frame on which the grids to be reoriented are held during the reversing operation. The frame is mounted on swivelling arms for swivelling therewith and for turning relative thereto between two positions, and the frame is turned through 180.degree. relative to the arms during their swivelling to one of such positions and held stationary relative thereto during the swivelling toward the other position. Guide rails are retractably positioned along the feed path of the grids to support those grids which are not to be reoriented, prior to the retraction of such rails which takes place before the release of the reoriented grid from the frame.

Abstract: Wires are picked from a loose bundle of wires which have been cut to length, prior to feeding to a processing machine such as a grid welding machine. The bundle is laid on a supporting table (23) so that end parts of the wires project freely beyond the table. A lifting beam (18) having a vertical slot (19) is then raised beneath the projecting end parts of the wires so that most of the wires are raised but the others are received one above the other in the slot. A gripper having clamping cheeks (20) is applied from below and grips the lowermost wire in the slot. The gripper is mounted on a carrier (2) which is movable parallel to the wire axes to pull the gripped wire longitudinally out of the slot.

Abstract: A multispot mesh welding machine has a row of welding electrode holders (2) on one side of the working plane of the mesh (Q, L), each holder (2) being electrically connectable to a selected one of at least two busbars (11, 12, 13, 14) which extend across the machine transversely of the direction of advance of the mesh (Q, L), by a respective switching member (9) movable with respect to the electrode holder (2). Each of the elctrode holders (2) has a contact tongue (6) overlying the contact faces of the busbars (11, 12, 13, 14,) and the respective switching member (9) is positioned between the contact tongue (6) and the contact faces of the busbars (11, 12, 13, 14).

Abstract: A shearing machine for severing parallel longitudinal members of grids or gratings has a horizontal guide-beam (9) which is stationary during the cut and upon which are provided counterbutts (17) in the manner of comb teeth; and a cutter-beam (10) which is movable parallel to and alongside the guide-beam during the cut and upon which blades (18) are provided in the manner of comb teeth, the blades cooperating with the counterbutts on the guide-beam to shear longitudinal members extending through notches (19,20) formed between adjacent counterbutts of the guide-beam and between adjacent blades of the cutter-beam. The guide-beam and the cutter-beam are guided in a machine frame for vertical movement into and out of a working position in engagement with a grid or grating and are associated for common motion in the vertical direction.

Abstract: The invention relates to a method of cutting off sections of a grating web of any desired length by means of shears. In the event there occurs a gap between the cross-bars of a welding machine, wherein the occurrence of the gap is established by a computer, so as to enable the introduction of the cutting blades of the shears into the mesh of the grating web, the grating web is cut in response to a signal from the computer.

Abstract: The invention relates to a grid welding machine operating on the electrical resistance welding principle and having continuous forward feed of the longitudinal wires. Groups of rotary electrodes and counter-electrodes cooperate in pairs and are arranged above and below the feed path of the longitudinal wires respectively. The electrodes and counter-electrodes are formed as rollers, opposite each electrode roller on the far side of the feed path of the longitudinal wires a counter-electrode being disposed in the same plane. The electrode rollers are spring-loaded individually in the direction towards the associated counterelectrode roller. Between the counter-electrode rollers and coaxially therewith there are arranged substantially circular cross-wire feed discs each having a number of grooves provided at angular intervals along the periphery of said disc for receiving said cross-wires.

Abstract: The invention relates to an automatic control device for a bending machine for use in the production of loops of bar or wire material for concrete reinforcement. The device includes a preselector for preselecting the type of loop required and determines the sense of direction and amount of bending required in that loop-type. Additionally, a selector is provided for selecting the length of each side of the loop of the type selected by the loop-type preselector.

Abstract: The invention relates to electrical multi-spot resistance welding machine for the production of welded bar gratings produced by welding cross-bars into the narrow side of parallel, upright flat bars. Such a machine has a pressure-beam which is guided vertically on a frame for lowering onto and raising away from the bars to be welded. Two rows of electrodes are disposed on the pressure beam, the rows being transverse to the feed path of the flat bars and the electrodes in the two rows being aligned in the feed direction of the flat bars and the electrodes of each aligned pair thus formed are connected to the secondary terminals of opposite polarity of a respective welding transformer.

Abstract: The invention relates to multi-spot-welding machines for the production of lattice gratings suitable for use for example as walk ways, and which consist of upright flat bars parallel to one another and cross-bars welded transversely into these and again parallel to one another. The flat bars are usually fed intermittently to welding electrodes. The machine of the invention has at least one pair of cooperating electrodes which are aligned in the feed direction of the flat bars and spaced apart a distance substantially equal to the desired spacing of the cross-bars. The or each pair of electrodes is pressed in turn against each pair or cross-bars to be welded and the upright flat bars themselves act as current bridges between the electrodes of the or each pair. An abutment supports the flat bars against the force of the welding electrodes and this abutment has considerably greater hardness and wear resistance than the flat bar material.

Abstract: A multispot welding machine for producing a mesh web from arrays of wire running skew to the longitudinal direction of the web and crossing one another has two endless circulating feeders which carry deflector-pins and each of which has a working run defining a different one of the edges of the mesh web to be produced, a wire-layer which is movable to and fro across the feeders and arranged to lay a number of wires alternately about a corresponding number of deflector-pins on the working runs of the two feeders, and a welding zone having means for welding the wires together at their crossover points. The endless feeders circulate in a common plane which is parallel with the plane of production of the web, the deflector-pins project substantially perpendicularly from the common plane, and the working runs of the two feeders have in the neighbourhood of the welding zone a greater separation from one another than before and beyond the zone.