FR2487247A1 - ACCUMULATOR TRAY MOLD - Google Patents

Abstract

THIS MOLD FOR MOLDING ACCUMULATOR BINS WITH THIN ELASTIC RIBS INCLINED AT ACUTE ANGLE ON THE TERMINAL WALLS OR ON THE BIN PARTITIONS TO ELASTICALLY RETAIN THE PLATES A LITTLE NEAR THE MIDDLE IN THE COMPARTMENTS INCLUDED WITH MANDRINS 24 D'ARONDE, AND EJECTION BARS 30 OF COMPLEMENTARY SHAPE WHICH SLIDE IN THE MORTITS TO ACT ON THE BOTTOM OF THE BIN AT THE TIME OF DISMOLDING. THE PARTS OF THE FOOTPRINT OF THE MOLD WHICH ARE USED TO MOLD THE RIBS ARE SHAPED, ON THE ONE HAND, IN THE SIDE FACES OF THE EJECTION BARS, AND, ON THE OTHER HAND, IN THE FACES OF THE MORTITS WHICH ARE OPPOSED TO THESE FACES LATERALS.

Description

148714?

  The present invention relates to molds for injection molding of accumulator tanks, the

  walls have thin and elastic ribs, ve-

  bare moldings, which project at an acute angle into the compartment or compartments defined by the walls. The ribs

  flex to different degrees, depending on the e-

  thickness of the elements which constitute the electrochemical components of the accumulator and they serve to firmly retain these components in the tank while giving them a flexible support which prevents them from vibrating. Good

  that the invention is particularly applicable to the

  lage of tanks with lead-acid batteries with multiple cells for automobiles, it is also applicable to batteries with single cell or other types

accumulators.

  Lead-acid storage batteries for cars

  have standardized external dimensions, class-

  in different categories. Typically, manufacturers

  cants provide accumulators with capabilities

  different energy accumulation in each category

  gory. To do this, we change the number of positive plates

  ves and negative in each element of the accumulator.

  However, by modifying the number of plates, we modify

  also the thickness of the element which must be posi-

  tightened and firmly retained in the corresponding compartment

  laying. Typically, accumulators with low energy storage capacity contain approximately nine plates per cell while accumulators with higher storage capacity can contain up to sixteen plates per cell. These elements vary in thickness between 2.4 cm, for low capacity accumulators

  and about 4.24 cm for high capacity accumulators

  quoted, according to the number of plates and specifications

  particulars of the manufacturer. In most accumulations-

  teurs currently found on the market, each element is kept spaced from the walls which delimit its compartment by relatively thick ribs (for example about 1.5 mm) which have come from molding

  perpendicular to the walls and which are in constant support

  Place the elements and hold them firmly in the middle of the compartment. We use larger ribs (that is to say, which form a more accentuated relief on the

  wall) for thin elements and, conversely, nerves

  narrower for thicker elements. These ribs are simply formed by cutting slits

in the massive mold cores.

  To realize a variety of battery models

  many manufacturers of accumulators keep at least one tray mold in stock for each

  accumulator model and they have to stop their chai-

  production to move from one model to the next.

  Other manufacturers have a smaller name in stock -

  number of molds but place additional inert spacers

  tional (for example additional separators) in each element of the accumulator to add thickness to the elements which include a smaller number of plates. However, this solution adds the additional cost of the spacer and, frequently, it involves handling the elements in the manufacturing workshop, in particular during installation.

of the item in the bin.

  At least one manufacturer molds oversized ribs

  born in a small number of standardized containers, then

  eg the ribs at the desired dimension, which depends on the thickness of the element intended to be housed in the tray in question. This technique is described in the patent

US 4,041,603.

  This solution requires a separate update operation

  the measurement and the tools necessary for this operation.

  Other manufacturers have proposed to mold elastic ribs (about 0.6 mm) inclined on the walls of the tank and which flex to an extent which is a function of the thickness of the element housed in the compartment considered. However, the molding of trays of this type is difficult if the ribs must have large dimensions (in height and in width). In this regard, it is difficult, even under the best conditions, to machine with precision fine slits inclined in a mold core with conventional tools without creating underpins or returns; and polishing the surfaces of these slots to a degree sufficient to reduce the frictional resistance which is exerted on the ribs during the demolding of the tray. Even when forming

  relatively smooth side slits, the fact that the Aur-

  face of the mold which forms the ribs is large relative-

  the thickness of these ribs creates such resistance

  release force that the force necessary to disengage the ribs from narrow slits frequently has the effect of stretching and deforming the ribs. Sometimes the

  ribs tear leaving parts of them

  same housed in the slot, which requires a stop of

  machine and mold cleaning. Finally, the experiment

  rience has shown that these molds require excessively long molding cycle times, on the one hand, to ensure

  an adequate filling of the mold impressions of the nerves

  which are narrow and poorly ventilated at the start of the cycle.

  key and, on the other hand, to clear the ribs of the em-

  preformed without deformation during demolding of the

the end of the cycle.

  The present invention relates to a mold for the injection molding of storage tanks made of material.

  thermoplastic with thin elastic ribs

  inclined ticks coming from molding on the walls of

  compartments to hold electrochemical components

  of the accumulator. A preferred embodiment of the mold comprises a core-carrying part which comprises one or more mandrel (s) for molding in the shape of the compartment (s), means serving to demold the tray from the mandrel (s), the mold release means comprising

  several dovetail ejection bars which slide

  alternately smells in mortises of complete form

  provided in the mandrel (s). More precise

  The invention consists in the fact that the parts of the mold cavity intended to form the ribs

  are formed in the divergent walls of the bars of

  dovetail junction and between these bars and the divergent walls (which diverge away from the

  external surface of the mandrel) mortises

  plementary. The ejection bar forms one side of the em-

  preinte molding of the rib and the wall of the mor-

  shut up forms the opposite side. Ejection bars and

  mortises are machined and polished separately before as-

  semiblocking. As a result, their critical surfaces are more easily accessible with the appropriate tools and a more precise finish can be obtained. Ejection bars

  help to clear the tray from the mandrel (s)

  concurrently pushing on the bottom of the tank and on the upper ends of the ribs to release the tank from the mandrel (s) without causing deformation

  ribs. In addition, the ejection bars

  place with tray during ejection, at least until the ribs are almost free from mortises

  of the mandrel (s). This displacement of the ejection bars

  tion with the ribs virtually eliminates rubbing

  ment on the ribs which would result from an interfacial adhesion between the ribs and the ejection bars while the ribs are still contained in their narrow mold cavities. This displacement, combined

  with the thrust exerted on the upper surface of the nerves

  vures, seems to reduce the effort required to free the ribs from the impression and to offset part of this effort from the base and the root of the ribs where it was

  concentrated so far thus causing deformation

  ribs. The release means also include an extraction plate to attack the edge

  of the tank and exert a mold release force on this edge.

  In a preferred embodiment, the plate of ex-

  traction and the ejection bars move joint-

- 248724?

  ment (for example over a distance of approximately 7.5 to 8.0

  cm) until the upper ends of the nervu-

  res are almost free from the extremity or extremities

  mites of the mandrel (s). At this moment, the direction of the ejection bars is reversed and the extraction plate releases the ribs which are now released from the bars

  ejection and, finally, the rest of the mandrel (s).

  While the extraction plate completes the separation

  between the tank and the mandrel (s), the ejection bars

  tion return to their retracted position and are ready for the next molding cycle. The molding footprint

  ribs is vented between the bars

  jection and mortises, which allows faster and more complete filling of these fingerprints during

injection.

  Other characteristics and advantages of the invention

  will appear during the description which follows. To the

  attached drawings, given only by way of example, - Figure 1 is a perspective view in section

  a multi-type accumulator tank of the soft type

  in a mold according to the invention;

  - Figure 2 is a plan view of the storage tank -

  figure 1; - Figure 3 is a side elevational view of a core-carrying part of a mold according to the invention, in the open position of the mold (that is to say with the

  female part of the mold moved towards the rear of the ob-

  servant); - Figure 4 is a front elevation view and

  section of a core-carrying part of a mold according to the

  vention, in the direction of arrows 4-4 of Figure 3 but in the closed position of the mold (that is to say coupled to the female or fixed part of the mold); - Figure 5 is a bottom view in section of the core-carrying part of the mold in the direction of the arrows -5 in Figure 3 but in the closed position of the mold (that is to say in the position coupled with the fixed or female part of the mold); - Figure 6 is an elevational front view in section of the core-carrying part of the mold shown in Figure 4 (that is to say with the fixed or female part of the mold remote) at a stage of the beginning of the demolding cycle, this figure showing the extraction plate in

  a partially advanced position and the ejection bars

  tion in a fully advanced position; - Figure 7 is a front elevational view in section of the core-carrying part of the mold shown in Figure 4 (that is to say with the fixed or female part of the mold remote) at a final stage of demolding cycle, this figure showing the extraction plate in a fully advanced position and the ejection bars in a retracted position; - Figure 8 is an enlarged perspective view of a mandrel and corresponding ejection bars of the mold of Figure 3, in the retracted position; FIG. 9 is an enlarged perspective view of the mandrel and of the mold ejection bars of FIG. 3,

  in the maximum extension position.

  Figures 1 and 2 are respectively views in

  perspective and plan of tanks 2 of thermo-accumulator

  multiple element plastics injection molded into molds according to the invention. The invention is however also equally applicable to single-element containers. End walls 4, side walls 6 and the bottom

  8 delimit tray 2 while inter-element partitions

  elements 10 divide tray 2 into a series of compartments

  individual elements 12. The electrochemical components

  of the accumulator, that is to say the

  that the separators and connectors are inserted into the various compartments 12 by the open upper face of the tank (that is to say the face delimited by an edge 16 and they are electrically connected so

  suitable for supplying the desired battery voltage

  tor. Thin flexible ribs 14 came from

  molding with partitions 10 and with termi-

  nales 4 and are arranged so as to form an angle (for example 600) with these partitions and walls. The ribs 14 have their base 13 on the bottom 8 and their root 15 on the partitions 10 and the walls 4. The ribs 14 flex to an extent which is a function of the different thicknesses of the components and they serve to keep the components spaced apart from the compartment walls and protect these components from damage due to

vibrations.

We will now describe the mold.

  Figures 3 to 5 are different views of the main

  pale elements of a mold according to the invention. FIG. 3 shows the core-carrying part of the mold seen from the front, in the open position of the mold, in which the

  female or fixed part of the mold is located behind the ob-

  servant. In a press, the half-molds move-

  would run horizontally and separate from each other in a vertical joint plane. Figures 4 and 5 are views showing the closed position of the mold, which show the core-carrying part 18 with the fixed or female part 74 of the mold in place and ready to receive the

  molten material (constituted for example by polypropylene

born).

  The core-carrying part 18 of the mold comprises a counter

  fixed plate 20, a core 22 and means serving to

  mold the tray 2 of the core 22. The core 22 comprises a series of mandrels 24 which have dimensions-corresponding

  to those of compartments 12. The mandrels 24 include

  nent a series of pairs of dovetail mortises 26 (for example trapezoidal), which are formed in their molding surface 28. The mortises 26 of each pair are arranged back to back, so that the ribs 14 molded in these pairs of mortises are directly

  face to face in compartment 12 of the accumulator.

  Furthermore, the mortises of a mandrel are directly opposed to the mortises of the mandrel (s) directly

-2487247

  adjacent (s), so that the ribs 14 formed in these mortises are directly opposed to each other on the opposite faces of the partition 10 formed between these ribs. A series of ejection bars 30 of complementary shape respectively fit in the corresponding ribs 26 and are adapted to slide alternately in these mortises as will be described later. Cavities 32 (Figures 8 and 9) formed in

  the divergent faces 88 of the ejection bars 30 delimited

  try the mold impressions of the ribs. The ejection bars 30 are joined to a base 34 housed in a

  groove 47 itself formed in a plate 40 of ejector

  tion or actuation of the ejectors. The base includes

  a part 36 forming a tenon adapted to be housed in sliding

  sement in a complementary opening 38 formed in the plate 40 for actuating the ejectors. A flange 42

  formed on the base 34 is spaced from the action plate-

  40 by an interval 44. Screws 43 are received

  sliding in openings 45 of the plate

  jection 40 and retain the base 34 in the groove 47 of the plate 40 but have dimensions studied to allow a relative displacement between the base 34 and the plate 40, so as to admit a withdrawal, as well as

will expose it in the continuation.

  The ejector actuation plate 40 is itself

  even actuated by hydraulic cylinders 46 bolt-

  born on the plate 40 in 48. Piston rods 50 exceed

  sant cylinders 46 slide through openings

  52 of the ejection plate 40 and are fixed in a

  adjustable to the fixed counterplate 20, as indicated

  qué (figure 4). Columns 51 are anchored in the plate

  than 20 and serve to guide the ejection plate 40 during

during the release.

  The mandrels 24 are kept tightly assembled to each other and to the core-carrying part 18 by

  fixed mounting plates 54 and 56. In this regard, the

  cines or bases 58 of the mandrels 24 diverge outwards

  laughing and cooperate with an opening 60 of complete shape

  Mentaire formed in the front mounting plate 54. The rear mounting plate 56 is then bolted to the front plate 54 and the mandrels are thus tightly pressed against each other. The fixed mounting plates 54 and 56 are rigidly fixed to columns 62 and rails 64 which are in turn rigidly fixed to

  the fixed counter plate 20 and serve to hold the plates

  ques 54 and 56 spaced from the counterplate 20. The ejection bars 30 protrude from the base 34 and through

  an opening 57 formed in the rear mounting plate

  re 56 then, beyond, they pass through the mandrels 24.

  An extraction plate 66 is adjacent to the front mounting plate 54 and is used, in combination with the ejection bars 30, to separate the tank 2 from the mandrels 24 after molding. The extraction plate 66 has a cavity 68 in the shape of a cross to cooperate with the fixed or female part 74 of the mold, as shown in FIGS. 4 and 5. The plate 66 is screwed (FIG. 5) to the rods pistons 69 of hydraulic cylinders 70 which, in turn, are bolted to the counterplate 20. Four guide columns 72 (Figures 3, 6 and 7) are anchored to the front fixed mounting plate 54 and serve both guide plate 66 and do

  coincide the core-carrying part 18 of the mold with the part

  fixed or female tie 74 during closing of the mold.

  Four coordination pins 73 are anchored to the ejection plate 40 by mounting plates 75. The coordination pins 73 slide through openings made in the mounting plates 54 and 56 to press against the rear face of the plate 66

  and they serve to maintain the spacing between the

  ques 40 and 66 during ejection.

  The fixed or female part of the mold 74 is not shown

  tee that in Figures 4 and 6 and it-comprises a main body 76 in which is formed a cavity 78. According to the usual technique, four cam doors 80 slide and adjust in the cavity 78 appropriately to define with this cavity a molding imprint 82 which has the shape of the tank. When the mold is opened, a spring 84 which acts in conjunction with an appropriate linkage (not shown) forces the doors 80 to slide.

  travel along surfaces 86 and, under this effect, move away

  hinder laterally from the core 22 to release the external face of the tank 2 from the mold. When closing, the doors slide back to the position shown

  in Figures 4 and 5. Appropriate means (not shown

  are provided for injecting the plastic material into the impression 82. These fixed parts of the mold are well known in the art and do not require

further description.

  We will now describe the operating mode of the mold.

  Figures 6 and 7 show the positions of the main

  pale elements of the core-carrying part 18 of the mold at different stages of the mold release cycle. When the injected thermoplastic material is solidified in the imprint 82 of the mold, the core-carrying part 18 of the

  mold separates from the fixed or female part 74 and

  drags with it the tray 2 which has tightened tightly around the core 22. At this stage, the various moving parts of the part 18 are approximately in the position shown in FIG. 4. When the core 22 is released from the fixed or female part 74 of the mold, the hydraulic cylinders 70 come into action and the extraction plate 66 advances slightly (from about 1.27 to 3.18 mm) to attack the edge 16 of the tank 2 which has slightly moved back relative to the face of the plate 66 as a result of the withdrawal. This slightly moves the plate 66 away from the front mounting plate 64 and the ends of the coordination pins 73. The hydraulic cylinders 46 are then actuated to advance the plate

  actuation of the ejectors until the pins

  coordination pins 73 are again in contact with the rear face of the plate 66. In this movement, the screws 43 slide in their housings and the interval

  44 existing between the plate 40 and the base 34 is formed.

  The interval 44 is adjusted so as to be equal to the shrinkage which occurs at the edge 16 and it thus prevents the ejection bars 30 from piercing the bottom of the tank 2 before the plate 66 can start to

  push tray 2 out of core 22. After these short shifts

  initial elements, the extraction plate 66, the actuation plate 40, the base 34 and the ejection bars

  move forward jointly to eject tray 2 from the

  drins 24 as shown clearly in Figure 6. The coordination pins 73 hold the plates 66 and 40 in their relative positions and thus prevent the plate 40 does not exceed the plate 66

  and that the bottom of the tank 2 is pierced by the ejection bars

tion 30.

  When the ejection bars 30 have advanced sufficiently

  ment (approximately 76.2 to 88.9 mm) so that the ribs 14 are practically disengaged from the mandrels 24, the action

  cylinders 46 are reversed as well as the direction of movement

  ment of the plate 40. When the plate 40 reverses its movement, the screws 43 slide in their holes 45 until their heads come into contact against the rear face of the plate 40, then pull the base 34 back and retract the ejection bars 30 in the mandrels 24 (Figure 7). While the ejection bars

  retract into the mandrels 24, the extraction plate

  tion 66 continues its forward movement to push the tray and release it from the mandrels 24 (FIG. 7). Then, the plate 66 reverses its movement and returns to the position

  shown in Figure 4, the mold closes and the cy-

molding key repeats.

  Figures 8 and 9 are perspective views on a larger scale of typical examples of mandrels 24 and ejection bars 30 according to the invention. Figure 8

  shows the ejection bars 30 in their retracted position

  tee or molding. In this position, the cavity 32 which is machined in the divergent faces 88 of the bars

  form a molding imprint of ribs in

  hoeing with the corresponding divergent walls 90 of the mortises 26 of complementary shape. The walls 90 of the mortises 26 diverge from the surface 28 of the mandrel 24 at an angle approximately equal to the acute angle that the ribs 14 form with the partitions 10 in the

tray 12 finished.

  The invention provides a mold which can be used industrially for injection molding of a storage tank of thermoplastic material which has thin inclined and elastic retaining ribs which protrude into the compartments of the elements of the tank, which mold can be easily machined and polished and which can also be implemented with industrially applicable molding cycle times, without causing

  no stretching, tearing or other deformation

  rib tables during demolding of the tank.

248724?

Claims (5)

  1. Mold for injection molding a tank (2) for   accumulator which comprises a bottom (8), side walls   rails (6) and end walls (4) which delimit a compartment (12) intended to contain the electrochemical components of the accumulator, this tank having a series of thin and elastic ribs (14), which have come in one piece with said terminal walls and   protrude at an acute angle thereto in said com-   part to maintain the electrochemical components roughly in the middle of the compartment, this mold comprising a female part (74) and a core-carrying part (18) which cooperate in the closed position of the mold to delimit a molding imprint corresponding to the tray said core-carrying portion comprising a mandrel (24) which has an external surface suitable for molding the   internal surface of the compartment, and means for   mold the mandrel pan, this mold being characterized by   what said demolding means include:   line of mortises (26) formed in the mandrel (24), each mortise being defined in part by at least one side wall (90) which is inclined inwards from the surface (28) of the mandrel, forming a angle approximately equal to said acute angle, ejector bars (30) of roughly complementary shape, each of which   alternately slides in a mortise (26) corresponding   laying, each of the ejection bars being defined in part by at least one face (88) juxtaposed to said side wall (90) of the mortise and being adapted to move between an extension position, release of the tank and a retracted tray molding position; a cavity (32) formed in said face (88) of each bar to define a rib molding imprint between said ejection bar and the corresponding wall of the mortise while the ejection bar (30) is in its retracted position; and means (46, 40, 34) for moving said ejection bars between the retracted position and the extended position so that the ejection bars (30) move with the ribs (14) to disengage these ribs of their molding impressions (32) when the tank (2) is removed from the mandrel (24).   2. Mold according to claim 1, characterized in that the container comprises a bottom, side and end walls and at least one partition (10) parallel to said end walls and which divides the container into at least two compartments (12) intended for contain electrochemical components of the accumulator, this tank comprising a series of thin and elastic ribs (14) formed integrally with the partition or with the end walls and protrude at an acute angle on this partition or these walls   inside said compartments, to maintain the-   said electrochemical components roughly in the middle a   inside said compartments, said holder part   core (18) comprising several mandrels (24) each of which has an external surface (28) intended to mold the internal surface of the corresponding compartment and in that said release means comprise: several mortises (26) with dovetail, each mortise being defined in part by opposite side walls (90) which diverge from said surface (28) at an angle approximately equal to said acute angle; and in that each of the ejection bars (30) is defined in part by opposite faces (88) which are juxtaposed with said   side walls (90) of the mortises, a cavity (32)   swam in each of these faces (88) defining a rib molding imprint between the ejection bar   (30) and the side wall (90) of the corresponding mortise   when said ejection bar is in the said retracted position.   3. Mold according to any one of the claims   1 and 2, characterized in that the container has an upper edge (16) and said release means comprise   first means and second means serving respectively Z487247   tively exert a push on the tank at its upper edge (16) and its bottom (8), to release   the mandrel tray, said first means being constituted   killed by an extraction plate (66) and the second means comprising said ejection bars (30). 4. Mold according to claim 3, characterized in that it comprises means (34, 40, 43, 44, 73) for coordinating the movement of the ejection bars (30) and that of the extraction plate (66 ) during demolding so as to prevent the ejection bars from passing beyond the extraction plate and from piercing the bottom (8) of the tank (2), said ejection bars (30) being in the retracted position to form said rib molding imprints (32) during molding and then moving with the ribs (14) to said extension position to release the ribs from their imprints   molding without excessive resistance or deformation has ribs.   5. Mold according to any one of the claims   1 to 4, characterized in that each mandrel (24) comprises at least two pairs of mortises (26), each pair comprising mortises arranged back to back on the opposite sides of the mandrel.