GB2169232A

GB2169232A - Wire drawing device

Info

Publication number: GB2169232A
Application number: GB08530634A
Authority: GB
Inventors: Georgi Kostov Petkov; Stamen Nedeltchev Stoev; Nedyalko Marinov Nedyalkov
Original assignee: NPSP po Hydroplastichna Obrabotka na Metalite
Current assignee: NPSP po Hydroplastichna Obrabotka na Metalite
Priority date: 1984-12-17
Filing date: 1985-12-12
Publication date: 1986-07-09
Also published as: GR853026B; JPS61180609A; DE3542293A1; HUT39639A; GB8530634D0; IT8548883A0; BG41686A1

Abstract

A wire drawing device of simplified design is so constructed that the hydroplasticising fluid is able to act simultaneously as lubricating fluid. The device comprises a hydroplastic working block (5) having disposed symmetrically with respect to the longitudinal axis thereof first and second multiplicators (17,18) the high-pressure chambers (15,16) of which are connected through first back-pressure valves (13,14) to a work chamber (6) in the hydroplastic working block and supply high pressure fluid, generally lubricating fluid, to the feedstock (10) being worked, and the low-pressure chambers (21,22) of the multiplicators being connected through second back-pressure valves (23,24) to an external supply source of hydraulic fluid. <IMAGE>

Description

SPECIFICATION Wire drawing device This invention relates to a wire drawing device for producing lengths of wire of indefinite length from a feedstock of an indefinite length, which device is for use in connection with mechanical engineering and electrical engineering activities.

A wire drawing device which is described in Bulgarian Author's Certificate No.35632 comprises an inlet nozzle, a shaping nozzle and pressure chambers. In advance of the inlet nozzle is provided a push-and-knurl mechanism and a bath for freely lubricating the surface of the metal being fed in, which components are attached to the housing of a hydroplastic working block. The inlet nozzle is provided upstream of the hydroplastic working block and the shaping nozzle is mounted downstream of it. In addition, there are two pressure chambers separated by a two-step piston having a central longitudinal passage in which there is mounted an intermediate nozzle.In advance of the housing of the hydroplastic working block and disposed radially around a high pressure chamber to which is supplied hydraulic working fluid are located a number of feed elements which are connected to a low pressure chamber. Each feed pulse element for supply of fluid to the high pressure chamber consists of a cylinder mounted to the housing of the hydroplastic working block by a detachable connection. In each cylinder is located a piston equpped with a set of valves.

A disadvantage of this construction of wire drawing device is the number of components required in its construction, in particular a substantial number of pulse elements, valves, passages and gaskets, which reduces reliability, lowers preformance, and creates conditions for a low rate of productivity. Such a complicated system for supply of hydrualic working fluid makes no contribution to the lubrication of the metal being processed which requires separate working elements. Moreover, no contribution is made to the required high pressure of fluid acting on the feedstock. Finally the disadvantage exists that the third nozzle mounted within the two-step piston moves backwards with the piston in a straight line when pressure fluctuations occur in one of the chambers, thus creating conditions for disturbing surface character of the metal and in some cases for feedstock fracture to occur.

According to the present invention, there is provided a wire drawing device which comprises a hydroplastic working block, an inlet nozzle and an outlet nozzle associated with a working passage through the hydroplastic working block, an outer hydrodynamic tube associated with the inlet nozzle and an inner hydrodynamic tube associated with the outlet nozzle and a fluid container attached to the hydroplastic working block and communicating with the interior of the hydrodynamic tubes, there being disposed symmetrically with respect to the longitudinal axis of the hydroplastic working block first and second multiplicators the high pressure chambers of which are connected through first back-pressure valves to the interior of the hydroplastic working block and the low pressure chambers of the multiplicators being connected through second back pressure valves to an external source of hydraulic fluid.

A wire drawing device embodying this invention has a relatively simple design which guarantees high reliability, high performance and high productivity. The working fluid which acts on the metal being drawn during use of the device may be a lubricating fluid so that the device of the invention then operates to provide a hydrodynamic lubricating layer of adjustable pressure parameters; there is then no need for provision of any other lubricating system. The high pressure in the hydroplastic working block which is set according to the plasticity equation results in tensile strength reduction in that part of the feedstock which is in the hydroplastic working block. The design of the device of the invention is such that it permits wires of indefinite length to be drawn from feedstocks of non-ferrous metals and different grades of steel.

For a better understanding of the invention and to show how the same can be carried into effect, reference will now be made, by way of example only, to the accompanying drawing which is a longitudinal section through a wire drawing device embodying this invention.

Referring to the drawing, there is shown a central working unit comprising a lubricating chamber 1 attached to an outer hydrodynamic tube 2 which is in engagement with an inlet nozzle 3 by means of a nut 4 attached to the housing of a hydroplastic working block 5. In the housing of the hydroplastic working block 5, there is formed a work chamber 6 in which is located a lubricating fluid. An inner hydrodynamic tube 7 with an associated outlet nozzle 8 is held by means of a nut 9 within the hydroplastic working block 5 which acts as a housing for it.

Extending along the longitudinal axis of the housing of the hydroplastic working block 5, there can be seen a portion of a feedstock 10 of indefinite length. Work chamber 6 is connected through first side channel 11 and second side channel 12 respectively by means of first back-pressure valves 13 and 14 with high pressure chambers 15 and 16 of first multiplicator 17 and second multiplicator 18 wherein pistons 19 and 20 are positioned. Above the larger diameter faces of the pistons 19 and 20 are formed low pressure chambers 21 and 22 respectively which are connected through tubes (not shown) with second back-pressure valves 23 and 24 respectively which are connected to a supply source for a hydraulic fluid.In the first and second multiplicators 17 and 18 are incorporated third back-pressure valves 25 and 26 respectively which are connected to another fluid supply source, in this case a source of lubricating fluid. Electrically operable signal units 27 and 28 are disposed in the first and second multiplicators 17 and 18 respectively.

The wire drawing device operates as follows: Previously elongated feedstock 10 is fed into the device, passing in turn through lubricating chamber 1, outer hydrodynamic tube 2, inlet nozzle 3, inner hydrodynamic tube 7 and outlet nozzle 8. The wire leaving outlet nozzle 8 is coiled around a drawing drum (not shown) which provides the tension for drawing the feedstock through the device.

When this condition has been achieved, provision is made for supply to the device of lubricating fluid from the second aforementioned supply source, fluid passing through ducts (not shown) and the third back-pressure valves 25 and 26 then the first back-pressure valves 13 and 14 to load and de-aerate high pressure chambers 15 and 16. Work chamber 6 is likewise filled and air displaced therefrom as fluid which is of highly lubricating character is charged to it.

At this stage, hydraulic fluid (oil) is supplied through ducts and second back-pressure valve 23 to low pressure chamber 21 of the first multiplicator 17 to establish a low-pressure P,. At this stage, low-pressure chamber 22 of second multiplicator 18 is not supplied with hydraulic fluid and is reserved for subsequent use. As a result of the multiplicating action of first multiplicator 17, the pressure of the lubricating fluid in the high pressure chamber 15 increases to a value P2 with the relationship P2 = KP, obtaining, K being the multiplication factor of the multiplicator. At this stage, the device is ready to operate in a conventional operating mode. The drawing drum rotates at its chosen working speed to initiate normal processing of feedstock 10 with indefinite length.During the travel of the feedstock through the device, a hydrodynamic wedge of lubricating fluid (oil) is produced in the outer hydrodynamic tube, providing for good lubricating of the feedstock. At the same time, a high pressure of this fluid is established in inlet nozzle 3. Under the conditions thus established, the processing of feedstock 10 is able to continue in the inner hydrodynamic tube 7 from which it passes through outlet nozzle 8. In addition to its lubricating properties, resulting in lowering of tensile stresses in the feedstock, the fluid which is supplied to the hydroplastic working block 5 promotes the rendering plastic of the metal being processed. There is a relatively low consumption of lubricating fluid and the high pressure chamber 15 is only discharged over a relatively long period.

When the volume of lubricating fluid in high pressure chamber 15 has dropped to a sufficiently low value, piston 19 actuates electrical signal unit 27 to provide for the feeding of lubricating fluid through second back pressure valve 24 to the low pressure chamber 22 of the second multiplicator 18 as a result of which the high pressure of lubricating fluid in the work chamber 6 and in the high pressure chamber 16 of the second multiplicator 18 is maintained by operation of the second multiplicator 18. While the second multiplicator is operating, the first multiplicator 17 is automatically prepared for its subsequent operation. The device of the invention is programmed so that the first and second multiplicators 17 and 18 operate alternately for a length of time sufficient for the entire feedstock 10 to undergo drawing in work chamber 6, emerging onto the winding drum with a coating of lubricating fluid after working under a guaranteed high pressure.

Claims

1. A wire drawing device which comprises a hydroplastic working block, an inlet nozzle and an outlet nozzle associated with a working passage through the hydroplastic working block, an outer hydrodynamic tube associated with the inlet nozzle and an inner hydrodynamic tube associated with the outlet nozzle and a fluid container attached to the hydroplastic working block and communicating with the interior of the hydrodynamic tubes, there being disposed symmetrically with respect to the longitudinal axis of the hydroplastic working block first and second multiplicators the high pressure chambers of which are connected through first back-pressure valves to the interior of the hydroplastic working block and the low pressure chambers of the multiplicators being connected through second back pressure valves to an external source of hydraulic fluid.

2. A device as claimed in claim 1, wherein the fluid container is connected to a source of a lubricating fluid.

3. A device as claimed in claim 1 or 2, which comprises electrically operating signal units associated with each multiplicator for actuating operation of one multiplicator and replenishment of the fluid container associated with the other multiplicator simultaneously to maintain supply of lubricating fluid to the hydroplastic working block under a pressure exceeding a predetermined minimum at all stages during a wire drawing operation.

4. Apparatus as claimed in any one of the preceding claims, comprising additional back-pressure valves in ducting communicating the high-pressure chambers of the multiplicators with a source of hydraulic fluid for supply to the high-pressure chambers.

5. A wire drawing device, substantially as hereinbefore described with reference to and as shown in the accompanying drawing.