FR2462950A1 - MACHINE AND METHOD FOR CONTINUOUS MILLING OF BATTERY GRILLS - Google Patents

Abstract

THE INVENTION CONCERNS A PROCESS AND A MACHINE ALLOWING THE CONTINUOUS MOLDING OF ACCUMULATOR GRILLS. IN THE PERIPHERAL FACE OF THE ROTARY DRUM 24 OF THE MACHINE IS MACHINE THE FOOTPRINT 42 CORRESPONDING TO AN ACCUMULATOR GRID. A CURVILINE-FACED SKATE 40 IS MOUNTED FIXED AGAINST DRUM 24 AND SLIDES ON DRUM 24. SKATE 40 HAS AN INTERNAL PASSAGE CONNECTED TO A DUCT 60 WHICH EXTENDS TOWARD THE PERIPHERY OF THE DRUM AND OF WHICH ONE END IS CONNECTED TO A SOURCE 66 OF MOLTEN LEAD UNDER PRESSURE, THE OTHER END BEING CONNECTED TO A STRANGLE OUTLET 58 WHICH MAINTAINS PRESSURE AND CONTROLS THE LEAD FLOW IN DUCT 60. APPLICATION TO THE SERIAL MANUFACTURING OF MOLDED ACCUMULATORS.

Description

The present invention relates to a machine and method for

  mold battery grids and,

  more particularly, to a machine and a process

  so much to mold such grids continuously.

  Currently. the battery gates are generally individually molded into molds having removable portions, the cavity of the configuration of said gates being machined in the form of surface grooves in the opposite faces of said mold parts. The faces of this mold, in which the cavity of the grid is machined,

  are periodically coated with a thin layer of pulp cork.

  or acetylene smoke (lampblack) that acts as an insulator to prevent the lead from cooling before all the grooves delineating the grid footprint are

  completely filled. The manufacture, by this process, of grill

  individual accumulators, is relatively slow and

  requires considerable skill on the part of the operator.

  In recent years, experiments have been attempted to mold accumulator grids in a more rapid and continuous manner using a rotating drum on the peripheral face of which is machined the desired imprint of the

  battery grid. Such molding machines in

  have raised many difficulties, especially those

  consisting of obtaining a complete filling of the superficial grooves

  the grid footprint using lead

  melted while rotating the drum at a sufficient rate

  fast. Because of these difficulties and many others, the continuous molding of battery gates using such drums has not been widely used.

industrial so far.

  The present invention therefore firstly relates to a machine and a method for continuous molding of

  accumulator grills and overcoming the difficulties

  countered in the processes and machines of the prior art.

  More specificaly. the present invention aims to pro-

  to set up a machine and a process which, in order to continuously mold battery grids, use a rotary drum in the peripheral face of which the impression is machined

  said grids, a complete and rapid filling of this

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  preinte being assured by directing the lead under a large pressure and in a quantity much greater than that necessary to fill the imprint of the grid when

the drum turns.

  The machine according to the invention comprises a shoe having a smooth curved surface, whose conformation

  corresponds closely to that of the cylindrical peripheral face

  only drum. This pad is held in a fixed position against the periphery of the drum when it rotates, so that

  to achieve easy sliding contact between these two -.

  elements. An internal passage opening formed in the pad opens at the surface of the drum and is connected to a source

  molten lead under pressure, the outlet orifice being

  by a suitable means to keep the molten metal flowing

  in the passage opening at a pressure greater than the pres-

  atmospheric pressure. Such an embodiment confers more

  important advantages that will emerge from the description

  below. The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which: FIG. 1 is an elevational section of an accumulator grid molding machine according to the invention, according to a plane perpendicular to the axis of rotation of the molding drum; FIG. 2 is a plan view of a continuous strip section of an accumulator grid molded into said machine; Figure 3 is a section through the line III-III of Figure 1; Figure 4 is a section through line IV-IV of Figure 3;

  FIG. 4a is a section on an enlarged scale

  Figure 5 is an enlarged fragmentary section illustrating a portion of the machine of Figure 1; Figure 6 is a fragmentary section through the line VI-VI of Figure 5;

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  Figure 7 is a fragmentary section illustrating an alternative embodiment of the pad of the machine; Figure 8 is a section through the line VIII-VIII of Figure 7; and FIG. 9 is a fragmentary elevational view with partial sectional view of another variant embodiment of FIG.

machine according to the invention.

  Referring firstly to Figures 1 and 3, it is seen that the machine according to the invention eomoorte a support frame 10 by means of which it is mounted on a support structure 12 of a tank 14 containing molten lead . The frame 10 may have any suitable embodiment and, in the example shown, it comprises a pair of spaced apart gutters 16 supported at their opposite ends on vertical threaded rods 18, so that they can be adjusted.

  vertically. A pair of pads 20 integral with the drops

  16 supports an axis 22 on which is keyed a tamper

  Molding shaft 24. A shaft stripping. 26 is connected to the axis 22 to rotate the drum 24 at the desired speed. In the example illustrated in FIG. 1, the drum

  24 turns counterclockwise.

  A pair of support bars 28 is mounted on the axis 22, on the opposite faces of the tembr 24, by means of

  pads 30. Each support bar 28 is attached to an

  tremité, by a screw 32, to its adjacent gutter 16 next

  a desired angle of inclination. A pair of guide bars

  34 spaced laterally is mounted on the support bars.

  port 28 with screws 36 and 3P which adjust the guide bars 34 in the direction of the support bars 28 or away from them. A pad 40 is mounted between the

guide bars 34.

  The desired pattern of the imprint of the accumulator grid 42 is machined in the smooth cylindrical peripheral face of the drum 24. This imprint consists of a plurality of circumferentially oriented grooves 44, and several transversely extending grooves 46. The throats 44

  are designed to form souls 44a and 44b extending

  The transverse grooves 46 are intended to form transverse webs 46a and 46b of the completed grid shown in FIG. 2. The webs 44b and 46b are normally wider than the webs 44a and 46a, and they form the outer frame of the web. grid completed. On one side of the grid, the groove 44 is widened to delimit a conventional welding tab 44c adjacent one end of each grid. On either side of this tab, the cavity of the grid protrudes internally from the lateral edges of the drum 24, so that the lateral external sections 48 of said drum 24 are in the form of continuous smooth surfaces. and

  cylindrical parts which are in contact with the same cylindrical surface

  that only beads 48a delimited by the grooves 44 and 46.

  In the illustrated embodiment, the drum 24 has a central core 50 at the lapping DériphérieIle extends a cylindrical flange 52-. . The imprint 42 of the grid is machined

  on the outer face of this rim 52-.

  The pad 40 is in the form of a metal block

  with a slightly inclined face 54 which marries

  the shape of the sections 48 and 48a of the outer face cy--

  the drum-24, which is in sliding contact with these sections. An easy sliding contact between the curved face 54 of the shoe 40 and the peripheral face of the drum 24 is obtained by adjusting the screws 36 and 38. In the embodiment of FIGS. 1 to 6 and of FIG. an inlet orifice 56 on one face and an outlet orifice 58 on its face

  opposite. An inner conduit 60 extends transversely across

  to the skate 40! is open to the curved face 54 and connects the inlet 56 and the outlet 58. This conduit 60 has a smaller section than the inlet and outlet ports, to which it is connected at opposite ends thereof through passage orifices 62 bent upwards. As shown in FIG. 6, the duct 60 extends in the same direction

  the impression 42, transversely to the drum 24. As -

  3, a duct 64 is directed downwards, from the inlet orifice 56, towards the molten lead contained in FIG.

  in the tank 14, and is connected to the outlet of a pump 66.

  A suitable drive shaft 68 extending upwardly from the pump is intended to drive the latter to

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  the desired speed. A similar duct 70 extends downwards into the tank 14 from the outlet orifice 58 and flows into this tank via a check valve 72, the importance of this restraint imposed by said valve 72 being adjustable by means of a control rod 74. The valve 72 makes it possible to regulate the flow rate of the flow of lead and

  its return pressure in the duct 60.

  The level of the liquid lead in the tank 14 is designated

  76. It should be noted that the region below

  drum 24 is at a certain distance beyond

  above the level 76 of the lead and that the pad 40 is partially immersed in the lead contained in the tank 14. The pad 40 is pierced with several orific-es cooling 78 arranged

  each above level 76 lead. In the form of reali-

  As shown, three orifices 78 of this type extend transversely across the pad 40, downstream of the conduit 60, and one of these orifices 78 extends transversely across

  said shoe 40, upstream of said duct 60.

  The upstream cooling 80 serves to prevent the molten lead from flowing in a clockwise direction from the conduit 60 and

  escape from the region separating the drum and the ex-

  upper end of the pad 40. The terms "upstream" and "downstream" are used herein in relation to

  in the direction of rotation of the drum 24. The orifices 78 are connected to

  dice by a set of tubes 80 suitable for cir-

  a cooling fluid (such as water) to

  40. Similarly, a thermocouple is housed preferably

  in a recess 82 in the shoe 40.

  In use, the drum 24 is rotated at the desired speed and the pump 66 is actuated to continuously supply the inlet port 56 with a molten lead alloy (for example at a temperature between 3710 C and 4270 C). The inside of the flange 52 of the drum is preferably cooled by air nozzles 84, so as to keep the molding surface of the drum at a substantially lower temperature (for example between 2040 C and 2600 C) at the solidification temperature. cast alloy. Therefore, the molten lead directed to the conduit 60 by the pump 66 through the inlet port 56 is cooled

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  rapidly when it comes into contact with the faces 48 and 48a of the grooves 44 and 46 on the peripheral face of the drum 24. Since this drum rotates in a counter-clockwise direction, the lead having a tendency to solidify on the surfaces 48 and 48a is scraped from these surfaces by a downwardly directed ridge 86 of the conduit 60, and tends to accumulate along this ridge. However, since the molten lead discharged in the conduit 60 by the pump 66 is in a large amount.

  excess of that necessary to fill the por-

  adjacent to the rotating impression, the circulation

  The lead stream passing through the conduit 60 is maintained at a relatively high temperature and sufficient to melt, disintegrate, or displace the solidified lead scraped from the surface of the drum. The fast and continuous flow of molten lead at high temperature in the conduit 60 therefore prevents the solidified lead from settling along the ridge 86, thus preventing an obstruction of said conduit 60. Moreover, since the valve 72 prevents the flow of lead to return freely to the tank 14 by passing through the outlet orifice 58, the lead present in the conduit 60 is advantageously maintained at a high pressure, higher than the atmospheric pressure. This pressure is sufficient to ensure a continuous supply of lead and to repress the molten lead in the regions of the grooves 44 and 46 which have just made an upward rotation opposite the conduit 60. In this way, we obtain a final and complete filling grooves 44 and 46 even when the latter are empty or greedy after they have turned in line with the conduit 60. Therefore, by the combination of an excessive amount of lead and a pressure greater than the imposed atmospheric pressure lead introduced into the footprint of E

  grid, we obtain an integral filling of the succes-

  of said footprint, while maintaining a cool-

  very fast inside the gorge. This rapid cooling results in a uniform and very fine grain structure of the lead alloy. This very fine grain structure is excellent in molded storage grids,

  because of its resistance to corrosion.

  As the regions filled with gorges

  44 and 46 perform an upward rotation in an anti-

  hour, they advance along the side of the ice pad 40

  by the orifices 78 on the side downstream of the conduit 60.

  As a result, the temperature of the lead in these grooves is progressively lowered so that, when the lead exits the end downstream of the pad, it has solidified to form a continuous band having the configuration of the battery grid. Preferably, this band S is removed from the upper face of the drum, so as to have cooled to a sufficiently low temperature to give it a sufficiently rigid consistency to easily grasp it. After this strip is out of the region between the pad and the drum, it is cooled substantially by the nozzles 84 which direct air currents to the inner and outer faces of the flange 52 when these faces rotate opposite said pad , and before the grid is removed. Subsequently, the band S is directed to a matrix (not shown) which cuts it into grids

separate accumulators.

  Typically, in a machine according to the present invention,

  In this invention, the drum has a diameter of about 7 cm, a width of about 8 cm, and it rotates at about revolutions per minute to reach a linear velocity of 28.65 m per minute. The battery gates are molded from a lead alloy containing about 0.9% Ca and O; 3% Sn, and they have a length of 13.9 cm, a width of about 5 cm and a thickness of 0.8 cm. Each grid weighs about 18 grams and the bands weigh about 126 grams per linear meter. At a linear speed of 28.65 m per minute, the strips use about 3.63 kg of alloy at the minute. The pump 66 has a capacity of about 20.43 kg per minute and can be used at full capacity or its inlet port can be adjusted so that this pump discharges a little less than its full capacity, depending on the capacity of the pump. the adjustment of the check valve 72. The pad 40 has a

  length of about 10 cm and a width of about 8cm. The con-

  duit 60 has a width of about 0.9 cm, a depth of about

  0.7 cm, and is located about 2.5 cm from the upper end

of said pad.

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  The vessel containing the lead is heated to a temperature of

  between 3990 C and 4270 C. With a water of

  cooling at a temperature of about 210 C and the air nozzles shown, the temperature of the pad is stabilized at about 301 C, and that of the peripheral face of the drum at about 232 C. Although these relative dimensions and other parameters

  given as an example and have no critical value.

  that, many fundamental data are important. By

  For example, it is very important to maintain a small

  the sliding between the curved face 54 of the pad 40 and the peripheral face of the drum. Since the temperature of the pad differs substantially from that of the drum, and some of these members have some temperature variations, it is recommended to maintain the length of the pad 40 at a minimum length compatible with the relatively fast solidification of the drum. strip grid, in order to maintain a close sliding contact between these

  two elements. In addition, a longer skid requires

  application of greater clamping force to the drum.

  bour to get close close contact with this

  deny, resulting in excessive friction. he is also

  desirable to provide a relatively narrow conduit 60 for -

  prevent the drum temperature from becoming excessive-

  high in the region of the latter in contact with the

  skate. In addition, it is important that the higher end

  of the pad and the part of the drum in contact with it are maintained at sufficiently

  to prevent melted lead under pressure from

  borders of these regions. The amount of molten lead delivered by the pump must be sufficiently excessive in relation to the amount required to fill the

  the grid, in order to keep the temperature sufficiently high

  of lead in duct 60 so as to melt and

  to evacuate lead that has solidified in the

  smooth wheels of the drum. Furthermore. the pressure exerted on the molten lead in the conduit 60 must be high enough to push this lead into all the gaps, or

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  good for overcoming any blockages of lead that may

  in grooves 44 and 46 of the impression when they are

  cause an upward rotation opposite duct 60.

  The shoe 88 illustrated in Figures 7 and 8 differs only slightly from the pad 40 described above. In this shoe 88 two

  90 and 92 of the molten lead flow are trans-

  versally through the skate. These holes are plugged at one end. At its opposite end, one of these orifices is

  connected to an inlet tube from the pump 66, the other

  fice being connected to an outlet tube extending towards the check valve 72. In the curved face 94 of the shoe 88, is

  machined conduit 96 similar to the conduit 60. However, this

  duit 96 is closed at opposite ends thereof. Several pairs of passages 98 and 100, inclined in opposite directions, respectively extend from orifices 90 and 92 to

  96. Thus, referring to Figure 8 and admitting

  while the orifice 90 is the inlet orifice and the orifice 92 is the outlet orifice, the molten lead is directed in the form of a continuous jet which flows upwards in the

  leads 96, by traversing the inclined passages 98, then des-

  This conduit leads from the conduit 96 to the discharge port 92 and from there opens into the lead tank via the check valve 72. It should be noted that, regardless of whether the lead in the skate be spared

  as illustrated in FIGS. 1 to 6 or in the

  nie illustrated in Figures 7 and 8, the conduit traversed by this lead is connected in series with the input and the output of the path traveled by the lead circuit. Therefore. the molten lead circulates continuously through the entire length of this conduit. This steady stream of molten lead at a

  temperature and under a pressure greater than

  atmospheric pressure avoids excessive cooling and prevents

  that the lead is deposited on the localized surfaces of the drum to which the molten lead is directed.-This also ensures that the solidified lead scraped from the

  drum by the lower edge of the pipe is melted,

  or otherwise eliminated in order to avoid an obstruction

  duct and incomplete filling of the grooves

  storing the imprint of the battery grid.

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  In the embodiment of FIG. 9, the difference

  1 is that a shoe 40a is mounted to the upper face of a drum 24 instead of being on its underside. When the skate is mounted so that it is not partially immersed

  in the molten lead contained in the tank 14, the temperature

  this skid is kept relatively high by means of

  Auxiliary Heaters 102. With the exception of this difference,

  and the operation of the variant embodiment of the

  Figure 9 are substantially identical to those of

described above.

  It should be noted that in each of the

  illustrated embodiments, the drum is disposed of

  not to come into contact with molten lead in the tank.

  This is desirable, not only to maintain this drum

  at a temperature advantageously low allowing a solidification

  but also because of the fact that

  bour is wetted by the lead bath, oxides and other surface alteration agents are formed which accumulate or appear on the peripheral surface of the drum. It should also be noted that lead flows between the tank and the

  driven in a completely closed path. In this way, we

  nihile almost completely the tendency for the formation and inclusion of film-and oxide particles in the metal

cast fusion.

  It goes without saying that many modifications can be made to the process and to the machine described and shown

  without departing from the scope of the invention.

Claims (12)

  1. Machine for continuously molding battery gates and characterized in that it comprises a rotary drum (24) having a cylindrical peripheral surface, means (22, 26) for driving said   drum in a direction at a predetermined speed   mined, said peripheral face having a recess (42) machined in depth and matching the shape of the desired configuration of the accumulator grid, a pad (40) mounted   in a fixed manner and having a curved surface (54) extends   with a close slip contact on a region   relatively small curvilinear of said circumferential peripheral surface   lindrique said drum (24), this pad (40) being drilled for   allow the passage of the molten lead, a part of the said   wise consisting of a duct (60) oriented directly towards said curved surface (54), transversely thereto,   and communicating with a circumferential region of the   said drum (24) passing substantially through the entire width of the cavity (42), a vessel (14) containing molten lead, means (56, 66, 64) directing molten lead from said vessel (14) audit passage in a quantity substantially   excessive compared to that needed to   said impression (42) when said drum (24) rotates opposite said conduit (60), means (58, 70) for returning the excess lead quantity of said conduit to said vessel (14), means (72) to maintain molten lead in said conduit (60) at a pressure above atmospheric pressure so as to ensure complete filling of said cavity (42), means (78) for   maintain the peripheral face of said drum (24) at a temperature of   sufficiently lower than the melting temperature of the lead, so that some of this lead tends to solidify against the periphery of said rotary drum   (24) within the circumferential projection of said cone   duit (60), the downstream side of said duct (60) being delimited by a transversely oriented edge (86) intended to scrape the lead solidify from the outer face of said drum (24), and means (66) forcing the lead molten to travel the conduit (60) at a velocity large enough to melt -2462 N / A   again, at least partially, and removing the accumulated lead, against said edge of said conduit (60) and return to the tank (14>.   -2. Machine according to claim J, characterized in that the means for holding the lead in the conduit   (60) at a pressure above atmospheric pressure   is an ornane (72) for throttling the flow of lead to prevent it from flowing freely from said conduit (-60) to the tank (14).   3. Machine according to claim 1, characterized in that the drum (24) and the pad (40) are both mounted so as not to be in physical contact with the lead contained in said tank (14), means to maintain said pad (40) at an elevated temperature selected for -maintening the lead in the conduit (60) to a temperature   desired means of molding, other means   of said rotary drum (24) at a temperature sufficient to   low to allow relatively fast and complete solidification of said lead in the region of the cavity (42) extending between the lower edge (86) of said conduit (60) and   the lower end of said pad (40).   4. Machine according to claim 1, characterized in that the passage comprises an inlet port (56) and an outlet orifice (58) connected in series with the conduit (60) to ensure a continuous flow of lead in merger on any the length of said conduit (60).   5. Machine according to claim 1, characterized in that the duct (60) extends transversely in the pad (40), closer to the upper end of said   pad (40) only from its lower end.   - 6. Machine according to claim 5, characterized   in that it comprises means (78) for cooling the   the upper extremity of the pad (40) to prevent reflux   lead from the region between the drum (24) and the end   upper half of said pad (40), and means (78) for cooling the lower extreme region of said pad (40-) to a greater extent than said region   extreme extreme of said pad (40).   7. Machine according to claim 1, characterized in that the passage comprises an inlet orifice (56) and an outlet orifice (58) located on opposite sides of the duct (60) and spaced radially outwardly thereof said inlet port (56) being connected to said conduit (60) through a radially inwardly inclined passageway (62), said outlet port (58) being connected to said conduit (60)   by a passage opening (62) inclined radially outwards   said molten lead flows into said conduit (60) towards the periphery of the drum (24) and leaves said conduit (60) in a direction away from the periphery of said drum (24).   8. A method of continuously molding accumulator grids on a rotating cylindrical drum in the peripheral face of which is formed a gate cavity, in   leader of molten lead from a tank to   successive faces of the peripheral face of said rotary drum   tif, by traversing a duct formed in a fixed   a relatively short curved surface, marrying the   from the periphery of said drum and being in sliding contact with   closely with the latter, the said crossing duct   essentially the entire width of said direct imprint-   in the vicinity of the periphery of the drum, a method of   characterized in that it consists in continuously directing molten lead through said shoe (40) to said duct (60) and to the portion of said cavity (42) facing said shoe (40) in a substantially excessive amount by to that necessary to fill said portion of said cavity (42); controlling the temperature of said drum (24)   so that part of the lead tends to become   diode against the periphery of said rotary drum (24) at the in-   interior of the circumferential projection of said conduit (60) to scrape the solidified lead against the outer face of said drum (24) by the upper edge (86) of said conduit (60) to return the excess molten lead to the vessel (14) from which it comes; and molten lead said conduit (60) at a speed sufficiently large to remelt at least partially and remove lead 2462tSO   accumulated at the lower edge (86) of said conduit (60).   9. The method of claim 8, characterized in that the lead flowing through the conduit (60) is maintained at a pressure greater than atmospheric pressure by throttling the return flow of said lead to the tank (14). 10. Process according to claim 8, characterized in that it also consists in cooling the drum (24)   until the temperature is sufficiently low to ensure   rapid and complete identification of the strip grid (S) when   it comes out of the lower end of the pad (40).   11. The method of claim 8, characterized in that the drum (24) and the pad (40) are maintained   out of physical contact with the lead of the tank (14).   12. Process according to claim 11, characterized   in that the conduit (60) is disposed circumferentially between the upper and lower ends of the pad (40), and in that the method further comprises cooling said pad (40) to the sides of the conduit (60) respectively upstream and downstream, said pad (40) being further cooled on the downstream side of said   conduit (60) than its upstream side.