LU82627A1 - METHOD FOR INJECTION MOLDING OF PLASTIC CONTAINERS FOR ELECTRICAL BATTERIES AND ACCUMULATORS AND MOLD FOR CARRYING OUT SAID METHOD - Google Patents

Description

BL-2911 / EM / BM

O / R / 7 GRAND-DUCHY OF LUXEMBOURG Patent No. Üü? ........... ”.......“ ^ Γ du Sj.uiUßÄ.J980 ..... I? | ro Dear Minister, r of Economy and Middle Classes

Book title · -s »or ........................................ Service de Intellectual property

“'PM? LUXEMBOURG

Patent Application I. Application

The company known as MCS - F.Ui MORANDI SneVia delta Resistenza 17 ._______ (i) Aîolinetto di Mazzano (Brescia) Λ Italy ____________________________________________________ 3 £ 9B ^ mMe ... peœ..X.ltyeM ^ Æ ... Ei ^ lirigerf Inç.eon8.en ... propr ... ind.ir 46. rue ........ (2) du Cimetière * Luxembourga________agying as agents______________________________________ * deposit (s) this fifteenth of July nineteen hundred and eighty___________________________________ (3) „at —.IsL .___________ hours, at the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for invention concerning: ________________ (4) batteries and accumulators electrical and mold for your implementation________________ of this process "__________ _______________________________________________________________________________________________________________________________ 2. the delegation of power, dated 3ß .., ... iy: id) .... ß: ß.ß.Q .___________ 3. description in lan gue ......... French ................................ of the invention in two copies ; 4. two___________ drawing boards, in two copies; 5. the receipt of taxes paid to the Registration Office in Luxembourg, the attic July one thousand nine oent eighty _____________ declares (s) assuming responsibility for this declaration, that the inventor (s) is (are): Ëi @ trg .. £ ranamcQ..MQlMÆÔZ, ..... Via.Æ ...... Yer ^ .taj .... Motine.tto..diIiazzana ..... ÇBr.esaia) .s ..... (5)

Italy................................................. .................................................. .................................................. .................................................. .................................................. ...............

claims (s) for the above patent application the priority of one (s) application (s) of (6) _________________....................... ................................ filed in (7) .......... Italy,................................................ .................................................. .

March 27, nineteen hundred and eighty ____________________________________________________________________________________________________ (8) ........ under So SIS? A / 80 _____________________________________________________ _______________________________________________________________________________________________ on behalf of .............. the applicant _______________________________________________________________________________________________________________________________________________________________ (9) elect (elect) for him / her and, if appointed, for his / her representative, in Luxembourg .... ................................

46 ....... rue du Cimetière, ....... Luxembourg __________________________________________________________________________________________________________________________________________________ (10) requests (s) the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, - with deferment of this issue to ............ “................................ .............month. (11) lJun ^ s ... jmnâataire .....................

.......... '* ——? - f— V “H. Procès-verbal de Dépôt' The above-mentioned“ application for a patent for invention has been filed with the Ministry of the Economy and

Middle Classes, Intellectual Property Service in Luxembourg, dated: 15 ji £ U & LJ980 t. . Pr. Minister ^ '·,% eg Economy and Average Classes, / - ". F *." J ΏΜΟ.

] J BL-2911 / EM / BM

'S. Claim of the priority of a patent application filed in Italy on March 27, 1980 under No 5137 A / 80 /: / i t

Ä V

i jl i

; PATENT

i; | Injection molding process of material bins! plastic for electric batteries and accumulators and mold for the implementation of this process'

The company known as: M C S - F.lli MORANDI S.n.c. Via délia Resistenza 17 Molinetto di Mazzano (Brescia) s Italy .1 i t ^ '1 ------- * · -. . .

4

*. W

The present invention relates to a method of injection molding of plastic hollow bodies affecting the cross section of a quadrilateral and it relates more particularly to tanks for batteries, electric accumulators and the like. The invention further relates to an improved mold for carrying out the method.

In the construction of electric batteries and accumulators, plastic tank-shaped bodies are used comprising a bottom, peripheral walls and an upper opening, these bodies being intended to contain the components of each module of the electrical appliance.

. · These tanks are currently being prepared according to a technique known and widely followed, by a molding process on injection presses which provides for the injection of plastic material into the mold, carried out at one end of the tank. to obtain, and more precisely on the bottom or the upper edge. The injection of plastic material can be carried out at one or more points on the bottom or edge of the tank, but in all cases it always takes place parallel to the axis of the body, or else along the length of the side walls. Tray.

! Such a molding technique requires that the walls of the tank to be obtained be thick in order to allow the mold to be filled with plastic and to obtain final dimensions respecting the required tolerances. In practice, it is not possible to produce tanks having thin walls.

Currently, although the trend would be to realize thin-walled bins, we have not been able to obtain satisfactory results.

| The possibility of reducing the thicknesses of the walls of the tanks having the indicated destination would above all have the advantage of appreciable savings in plastic material, in addition to a reduction in weight. However, the injection process described above and so far does not allow this.

I 35 The injection of plastic material carried out at one end of the tank to be carried out reduces the production capacity! »- potential of an injection molding machine with already finished characteristics, insofar as the path that the material is% * --jr%, <'2 obliged to carry out to pass from one part to another of the imprint in the mold and / or the high thicknesses required require significant time to fill the mold first and then cool the part.

The possibilities of injection molding machines are furthermore also limited by the fact that only molds with a limited number of impressions and, more generally, with a single impression, can be used.

Indeed, according to known techniques, the imprint 10 on the mold is provided so that the large surfaces of the piece extend in the direction of closure of the mold.

This in itself implies using high-power presses to contain the thrusts in the closing direction \ of the mold, even when the latter has a single imprint. 15 Thus, to use molds with several cavities, it is necessary to provide presses of even greater power, which is not economical.

It should be noted, moreover, that with the injection process used up to now, the poin-20 Çon intended to form the cavity of the tank obtained must be centered and locked in the mold, to avoid swerves when injecting material.

It is therefore necessary to provide the mold with means for centering the punch, means which, of course, contribute to complicating the apparatus.

In cases where means are provided for blocking the punch during injection, zones of cold junction are formed in the walls of the tank at the level of said means when the latter are removed. These areas can compromise the use of the bins as they tend to create electrical problems with the battery or the like.

The use of conventional molds also implies the need to extract the part from the mold and therefore have mechanical means capable of performing this function.

Attempts have been made to obtain tubs having the above-mentioned function and having reduced thicknesses by providing for the formation of the tub in two halves of "Ü" sections molded separately and joined together by welding techniques. appropriate.

However, such bins are not only difficult to achieve, but also economically unprofitable.

The main object of the present invention is, on the contrary, to eliminate the aforementioned drawbacks and disadvantages of known techniques and to allow the production of tubs in a single piece with walls of reduced thickness by fully utilizing the production capacities of the presses. injection of the conventional type and using molds of a simple structure and construction comprising one or more impressions, preferably and advantageously two or even more than two impressions, for molding several pieces simultaneously.

The molding process according to the invention uses a mold with at least one imprint and a punch intended to extend and be extracted from said imprint * and is characterized in that it consists in injecting plastic material. 20 as in the mold cavity at at least two opposite side walls of the tank to be obtained and at an intermediate height between the bottom and the top of the tank.

Thus, the plastic is injected into the impression, in at least two opposite directions, both directed transversely with respect to the container to be obtained, or else in directions perpendicular to the major axis of said container to be produced.

Always according to this product, one can carry out the in-! jection of plastic material at a single point of each of the two opposite walls of the tank to be obtained, or else at several points of these walls separated in height, but always in the zone between the bottom and the top of the tank.

The injection of material thus carried out makes it possible to rapidly fill each impression of the mold, the path that the material must take to reach the zones of the impression furthest from the points of injection. , anyway, shorter than in the prior art.

11 "

This therefore results in the possibility of significantly reducing the thicknesses of the walls of the tank obtained without ever compromising the speed and correctness of filling the mold in order to obtain suitable tanks. The reduction in thicknesses itself implies a reduction in the cooling times of the injected material which, together with the speed of filling of the mold, makes it possible to take full advantage of the production capacities of the injection press used.

The injection of material carried out in at least two opposite directions directed transversely with respect to the mold cavity, and therefore to the punch intended to form the cavity in the tank obtained, eliminates the need to guide and center the punch during the injection. In fact, the thrusts originating from the pressure of the material injected in opposite directions are themselves sufficient to ensure correct centering of the punch. The conventional mechanical means for centering the punch are therefore also eliminated and, consequently, the drawbacks generally caused by the use of these means 20 for the tray itself and its use.

The invention also relates to a mold for implementing the method, a mold comprising two half-molds, one of which is fixed to a part of the fixed type and the other to a mobile part of a molding press, both half-molds having 25 connection surfaces situated in a vertical plane and indentations delimiting in combination with movable punches corresponding to vertical extraction as many cavities which correspond by their shape and their dimensions to the tank to be obtained which has two large walls, two small walls 30 and a bottom, characterized in that the large walls of each mold cavity are parallel to the direction of closure of the mold, while the small walls are perpendicular to said direction and parallel to the joint plane of the two half-molds , the bottom of the tank being defined by a mold sector so-35aire of the movable part so that, the mold being open, the tank obtained can fall freely down during I retreat it of the corresponding punch, at least one of the two half-molds having at least one pair of pouring-outlet channels in the cavity in opposite directions and at level 5 "of at least two opposite walls of the tank to be obtained .

'”\ \ \

'AT

\ __ i; - • '* 6 Other characteristics and advantages of the invention will emerge from the detailed description which follows with reference to the appended drawing given solely by way of nonlimiting example.

5 In the attached drawing:

Fig. 1 is a cross section of the closed mold, obtained in the plane of the plastics pouring channels, ie along the line I-I of FIG. 2.

Fig. 2 is a central section of the mold, along line II-II of FIG. 1.

Fig. 3 is a section of the open mold with the punches being extracted and the part being discharged, falling by its own weight.

Fig. 4 is an interior view of the mold in the conditions conforming to FIG. 3 and according to the arrows IV-IV of the same figure 3-

Fig. 5 is a perspective view of an example of a tray that can be obtained.

The method described above essentially provides for the production by injection molding of a tank 10 affecting the section of a quadrilateral and comprising two large vertical walls 11, two small vertical walls 12 and a bottom 13, according to the representation of the drawing. and in particular in Figure 5.

This molding process uses, for example, a mold constituted by two elements or mold halves 1-2, one of which is fixed to the fixed part 3 and the other to the movable part k of a horizontal injection press. current, not shown here.

The arrows A-B in FIG. 1 indicate the directions of closing and respectively opening of the mold.

The two mold halves 1-2 have indentations l'-2 'which delimit in combination with one another and with a punch 5 which can be withdrawn vertically perpendicularly to the directions of closing and opening of the mold, a cavity whose shape and the dimensions correspond to those of the tank | 10 to perform.

-L In the accompanying drawing, there is shown a mold with two · 7 cavities and two punches for the simultaneous formation of two trays. However, the mold cavities could be more than two in number or there could be only one, depending on the requirements, the power of the press used, etc.

In all cases, each cavity of the mold is formed so that the large walls 11 of the tank to be obtained are parallel to the closing direction of the mold, while the small walls 12 are arranged perpendicular to this direction, that is to say ie parallel to the joint planes. 6 of the two halves.

. The bottom 13 of the tank is itself defined by a base sector 7 of the linked mold and which can move with the movable half 2 (see FIG. 3) and designed to be inserted, when the mold is closed, in a housing correspondent 8 formed in the fixed half in vertical alignment with the corresponding imprint and therefore with the punch corresponding to said imprint.

In the mold, in association with the cavity or each cavity, the casting channels 9-9 ′ of the plastic material are formed, which start from the injection nozzle 1 ^ of the material and which open into said cavity. imprint in opposite directions and at an intermediate height between the bottom and the edge of the tank to be obtained.

25 The pouring channels 9-9 'provided for each cavity may be two in number opposite one another as shown in FIGS. 1 and 2, without however eliminating the possibility of providing several pairs > opposite pouring channels, possibly separated in height. In addition, the casting channels 9-9 'can open; . at the level of the large walls of the tank to be obtained and / or at the level; small walls. Casting of the hot channel type for supplying material to at least two walls of the tank may comprise a fastener of the conventional type (of round, rectangular shape, etc.) 35 or submerged, or else to a tunnel with automatic sectioning, with or without carrot rejection.

A mold of the type indicated k has the advantage that the thrusts of the injected material corresponding to the large walls of the part are contained and supported directly by

•. NOT

'* 8 the mold surfaces, while the pushes at the level of the small walls must remain supported by the closing power of the press. As a result, with equal press power, it is possible, compared to the conventional technique and · 5 used previously, to have and use several impressions in the half-mold., Which is all to the advantage of an increase in yield of said press.

The controlled injection of material carried out in opposite directions on at least two opposite walls of the tank to be obtained 10 guarantees automatic and correct centering of the punch in the mold, without any need for any auxiliary centering means.

Thanks to the fact that the base sector 7 for forming the bottom of the tank can move with the movable half, there is also the advantage of automatic demolding of the tank, without the need for extractors. Indeed, when the movable mold half 2 is distant from the fixed half-mold 1, below the molded tray, there is no obstacle for the tray to fall freely by its own weight 20 while the punch 5 is moved upward, as shown in Figures 3 and k of the drawing, the upward movement of the tray being generally prevented by the blocking effected by an insertion 15 provided in the mold for guiding the punch.

The mold described above has the advantage that the simple insertion of corners 16 of various and appropriate heights into the mold cavities (see FIG. 2) makes it possible to obtain tubs of various heights, without this having to be done. disassemble the mold or modify the overall structure, which is necessary with the prior art molds.

The molding process and the mold described make it possible to injection mold plastic tubs having walls of reduced thickness, the time required for cutting is reduced even if presses with low closing power are used, production being thus increased and the cost reduced.

1: Of course, the invention is not limited to the embodiment K which has just been described and which has been shown '· k'! »% \ 9 to the accompanying drawings. Many modifications of details can be made without departing from the scope of the present invention.

¥ "" i i 4

Claims (1)

'' CLAIMS 1 ° - Injection molding process of plastic tubs, in particular for batteries and electric accumulators, and in which a mold is used, at least, an imprint and a punch intended to extend and to be extracted of said imprint, characterized in that it consists in injecting plastic material into the imprint of the mold at at least two opposite side walls of the container to be obtained and at an intermediate height between the bottom and the top of the bac. * 10 2 ° - A method according to claim 1, characterized "in that one performs the injection of plastic material into the mold cavity in at least two opposite directions both directed transversely to the tank to be obtained, in directions perpendicular to the long axis of the container and of the punch intended to form the cavity in said container. 3 ° - Method according to claim 1, characterized in that one performs the injection of plastic material into the mold cavity at a single point of each of at least two opposite walls of the tank to be obtained. 4 ° - Method according to claim 1, characterized in that one performs the injection of plastic material into the imprint of the mold simultaneously at several points of each of at least two opposite walls of the tank to obtain, these points being offset in height. 25 ° - Method according to claim 1 and any one of claims 2 to 4, characterized in that the material is injected in two opposite directions of at least two side walls by hot casting with classic, or submerged, or tunnel attachment. 6 ° - improved mold intended to implement the molding process according to claim 1 and or any one of claims 2 to 5, and comprising two half-molds (1-2) one of which is fixed to a part of the fixed type and the other to a movable part of a molding press, the two half-molds having connection surfaces located * // in a vertical plane and indentations delimiting in combination with movable punches corresponding to extraction. / • “11 t vertical as many cavities which correspond by their shape and their dimensions to the tank to be obtained which comprises two large walls, two small walls and a bottom, characterized in that the large walls of each mold cavity are parallel 5 to the direction of closure of the mold, while the small walls are perpendicular to said direction and parallel to the joint plane of the two half-molds, the bottom of the tank being defined by a sector of mold integral with the movable part so that the open mold, the container obtained can fall freely downwards when the corresponding punch is withdrawn, * at least one of the two half-molds having at least one pair of pouring channels opening into the cavity in opposite directions and at at least two opposite walls of the tank to be obtained. 15 7 ° - mold, according to claim 6, characterized in that it comprises at least one removable insertion intended to be fixed in one, at least, of the cavities to modify the height of the tank to be obtained. :. · / S ««