FR2473948A1 - Injection moulding machine - with multicavity component embossed numbering system comprising coaxial slings which can be automatically indexed - Google Patents

Abstract

Multiimpression injection moulding tool is fitted with a series of concentric rings each bearing a series of numbers or other characters at intervals which match the space between adjacent mould cavities. Rachet systems allow each ring to progressively index by one cavity so that each successive moulding cycle produces mouldings with different numbers. Used esp. for moulding items for security systems, so that each moulding of a set within the total numerical capacity of the concentric rings has a unique number which is not, to lay eyes, part of a simple sequence of serial numbers. Esp. for six rings each numbered 0-9, the first moulding cycle produces mouldings bearing the nos. 000000 - 999999; then if one ring is indexed round the next set of mouldings are 100000, 211111, 322222, etc.

Description

FRENCH REPUBLIC

NATIONAL INSTITUTE

INDUSTRIAL PROPERTY

  PARIS Y N of publication: (Use only for

reproduction orders).

2,473,948

REQUEST

OF PATENT INVENTION

  No 80 01 171 (9) Mold for injection molding of coded parts,

  International classification (Int. Cl. 3).

  Deposit date........................

Priority claimed:

  for example sealing members.

B 29 F 1/022.

January 21, 1980.

    Date of availability

  request public ............ B.O.P.I. - "Lists-" n 30 of 24-7-1981.

  Applicant: DE LIMA CASTRO NETTO Eduardo, residing in Brazil.

  Invention of: Eduardo De Lima Castro Netto.

  Holder: Idem Mandatory: Cabinet Lavoix,

  2, place d'Estienne-d'Orves, 75441 Paris Cedex 09.

  D Sale of booklets at IMPRIMERIE NATIONALE, 27, rue de la Convention - 75732 PARIS CEDEX 15 A1 @

  The present invention relates to injection molding

  joining plastic parts numbered or otherwise coded using a multi-cavity mold. We already know a mold in which the imprints

  are arranged in a row and are crossed by ban-

  hardened steel on which numbers or letters are engraved in such a way that each strip presents a number or a letter with each imprint. The bands are continuous and circulate by embracing suitable wheels provided for

  ends of the mold, while the back strands of the ban-

  do not pass through the imprints but on the contrary behind the mold. Between each molding operation and the next, the bands advance to present the number or the

  next letter to fingerprints. This type of mold presents dif-

  major drawbacks, one of which is the complexity of the device used to actuate the bands, which can be hydraulic, electromagnetic or mechanical. For engraving

  and the order of the bands, one must take into account the numbering-

  ge or sequential coding of parts or articles produced.

  The object of the invention is to produce a sim-

  folded and extremely effective for multiple moldings producing numbered or coded articles and, in one form

  preferred embodiment, making it possible to produce such articles

  keys without any repetition of combinations in as many as possible but without taking production into account

sequential of these combinations.

  According to the invention, an injection mold comprising two half-molds which can be separated after each operation

  molding and having conjugate working faces de-

  limiting between them several molding imprints and injection channels which open into said imprints,

  is characterized in that it comprises concentric rings

  as provided in a first half-mold, which can turn

  ner around a reference axis perpendicular to said conjugate faces and form portions of said imprints

  at regularly spaced points around the reference axis

  rence, each ring presenting towards the inside of each

  imprints a brand that is different from the one it pre-

  feel other fingerprints, ways to rotate

  one of the rings in successive steps so that its marks

  that they are presented one by one to said imprints and to rotate each of the other rings by one step each time the previous ring has completed a turn, like this

  occurs in a mechanical counter, and means of ac-

  actuation for actuating said rotating rings by one step at each separation and reconciliation cycle

half-molds.

  According to a preferred characteristic, the rings,

  each of which may be provided with marks produced under the form

  me of numbers or letters distributed in sequence on its periphery, are adjusted and pressed against each other when the two half-molds are brought together so that

  their conjugate surfaces are in contact with each other.

  To be sure there will be no repeat

  tition of combination of numbers or letters between the different footprints, each footprint is previously provided with an engraved number or letter which does not move with

  rings. In this way, the mold can produce without re-

  petition as many u-combinations as possible

  using the marks existing on the rings and on the em-

prints.

  In the preferred embodiment of the invention, the mold has ten cavities crossed by six rings, each of which is engraved with the numbers 0, 1, 2.13; 4, 5, 6, 7, 8, and 9 or the letters A, B, C, D, E, F, G, H, I and J, all zeros, all some, etc., being aligned, at start of production along spokes which extend from the reference axis towards the imprints which already bear the numbers 0,1,2. .9 respectively permanently engraved. Therefore, in the first operation of

  molding, the ten pieces: .or articles produced are therefore bare-

  numbered 0000000, 1111111, .. 9999999, the first digit

  being the one permanently engraved in the imprint

  you considered and the others being those of the rings.

  The first ring to rotate is preferably the one that produces the second digit in the series (the first being the fixed digit), so that in the molding operation

  next, the ten pieces will be numbered 01000000, 2322222 ..

  9099999. When the first print produces the article number

  rotated 0900000 and that the last product numbered item

  9899999, the next cycle of opening and closing the movement

  will also move the second ring by one step, so that the articles produced will have the numbers 0010000,

1121111 ... 9909999.

  The result of using a numbering mode

  age like this is to avoid repeating combinations

  before ten million digital items were produced

  rotated from 0000000 to 9999999. In addition, the articles are produced without numerical sequence but without repetition, which is of great interest when the articles must be used with safety but that it is not desirable that third parties know advance the next batch numbers

  of a series. This is very advantageous in the case of the pro-

  duction of tamper-evident sealing members, such as, by

  example, those described in the U.S. Patent No 4.106.801.

  Other features and advantages of the invention

  tion will appear during the description which follows.

  In the accompanying drawings given solely by way of example, FIG. 1 is a sectional view of a constructed mold

  according to a preferred embodiment of the invention, mainly

  following the line I-I of FIG. 3;

  Fig. 2 is a plan view of the face of a half

  mold of the mold of FIG. 1; Fig. 3 is a plan view of the face of the other half-mold of the mold of FIG. 1;

  Fig. 4 is a bottom view of the drive mechanism

  dragging of the outer ring of the half-mold of FIG. 3; Fig. 5 is a bottom view of one of the other drive mechanisms; and Fig. 6 is a side view of the mold in position

semi open.

  According to the embodiment shown in the drawings and which constitutes a preferred embodiment of the invention, a circular injection mold comprises two

  half-molds 1 and 2 having conjugate faces which are

  join in 3 and delimit between them ten footprints 4 (u-

  in the half-mold 1) used to mold numbered labels. As shown more clearly in FIG. 2, the indentations define parts 5 molding plates which are arranged radially around the center

of the mold.

  The half-mold 1 is the movable part when the mold is mounted in the injection machine and the half-mold 2 is fixed and has a central injection nozzle 6. The half-mold 1 has an interior cavity 7 enclosing a sliding plate 8 on which project a main ejection pin 9 and ten pairs of ejection pins

  secondary 10 which precisely cross cor-

  correspondents arranged in the half-mold 1 and which extend

  to the latter's working face. The ejection pin

  main tion 9 is aligned with the injection nozzle 6

  provided in the second half-mold 2 while the two bro-

  ejection pins 10 of each pair of ejection pins

  condaries are engaged in a corresponding impression 4.

  The ejector carrier plate 8 is itself mounted on a metal part 11 which passes through a hole in the rear plate 12 of the half-mold 1, and, on the other side, it is provided with a head 12a whose diameter is greater than that of the hole and which is kept away from the plate 12 by a spring. The working face of the half-mold 1 is hollowed out of ten channels 13 which start from the end of the hole crossed by the main ejection pin 9, each channel ending in a throttle 14 at the point where it communicates with the

  part of the molding of the imprint plate 4 corres-

laying.

  Qaunt in the second half-mold, it has a structure

  composite or laminated in the sense that it includes a

  front part which defines the working facet, a part

  intermediary in which the numbering mechanism is mounted

  floor and a rear or base part which is connected to the

  injection machine positive injection (not shown). The front part comprises an outer ring 15 provided with an outer rim 16 serving to ensure the exact positioning of the other half-mold 1 and of a flat and smooth face which

  cooperates with the combined working face of the half-mold 1.

  Io Along the inner periphery of this smooth face, the crown 15 has ten small cavities at the places where the parts 5 of the impressions 4 formed in the other are

  half-mold 1. Elements 17 in which are engraved indi-

  empty fingerprint numbers (0, 1, 2, 3, 4 ... 9)

  are rigidly fixed in these small cavities.

  Inside the crown 15 are arranged six

  cylindrical rings 18, 19, 20, 21, 22 and 23 split radially-

  ment in 60 as can be seen in FIG. 3. The ring 23

  the innermost one has a cone-shaped inner lip

  that 24 which cooperates with a frusto-conical element 25 which completes

  te the front part of the half-mold 2. All the rings 18 to 23 carry the ten digits 0. 1, 2, 3, 4, 5, 6, 7, 8 and 9 engraved

  at regular intervals, so that when they are cor-

  aligned straight, the rings form with the gra-

ves 17 combinations made up of seven digits and available

  located along the radial lines corresponding to parts 5

of imprints 4, (see Fig. 2).

  The frustoconical element 25 has a central hole which comprises a cylindrical part and a conical part separated by a shoulder 26. The conical part and the spreading

  26 correctly position the inner end of the information nozzle

  jection 6 when the mold is closed; the shoulder 26 serving

  also to support one end of a compression spring

  sion 27. The intermediate part of the half-mold 2 comprises a support element 30 fixed to the base plate 28 by three

  screw 29 (of which only one is visible in Fig. 1) and which pre-

  feels a hole with two diameters, that is to say a hole

  ge comprising an upper part of small diameter and a lower part of larger diameter, these two parts

being separated by an inner flange 31.

The second end or lower end of the compression spring 27 is pressed against the upper surface of the flange 31, while the head of the nozzle

  injection 6 is retained in said part of large diameter

  meter of the drilling of the support element 30. The conical element, which is biased towards the outside by the spring 27, sees its movement limited by three screws 32 (of which only one is visible in FIG. 1) whose heads are engaged with

  clearance in cavities 33 of the support element 30.

  Said intermediate part of the half-mold 2 comprises

  also takes an outer ring 34 between the base plate 28 and the outer ring 15 of the front part of the half-mold. This ring 34 is spaced from the support element 30 to delimit in an annular space which contains

  six toothed wheels 35, 36, 37, 38, 39 and 40, which include

  carry central sleeves which project upwards and have diameters respectively identical to those of the corresponding rings 18, 19, 20, 21, 22 and 23. The

  wheel sleeves 35 to 40 are coupled to the corresponding rings

  laying 18 to 23 by lugs which project from top to bottom on the rings and penetrate into radial slots made in the corresponding sleeves, which allows the rings split in 60 to expand and contract to a limited extent . The toothed wheels 35 to 40, which can rotate relative to each other around the support element 30, cooperate in a manner which will be described below with a group of five identical toothed pinions 41, 42, 43, 44 and 45 mounted one above the other on a

load-bearing pin 46 fixed to the base plate 28 by a screw 47.

  The set of pinions is housed in a cavity in the crown 34, outside the space in which the toothed wheels are

housed.

The upper toothed wheel 35, which drives the outer split ring 18, is shown seen from below in FIG. 4, on which it can be seen that this wheel is provided with ten ratchet teeth 48, so that a rotation of this

gear with an angle corresponding to the pitch of the displaced teeth

  this the numbers on the ring 18 from a footprint 5 to an-

  be. However, the ratchet teeth 48 are formed only in the upper half of the toothed wheel 35, while the lower part of this wheel is free of teeth, with the exception of six gear teeth 49 arranged on an arc

  limited to one step of ratchet teeth 48.

The ratchet teeth 48 cooperate with two diametrically opposite pawls and 51, of which the pawl 51 retains

the toothed wheel in each position and the pawl 50 drives

  does this gear wheel under the action of a slider 52 which is

in turn driven by a lever 53 integral with this coulis-

bucket. The two pawls 50 and 51 are properly mounted

in suitable cavities in the outer crown

  lower 34 of the intermediate part of the half-mold 2, the

  vier 53 emerging radially outside of this crown.

The six teeth 49 of the gear 35 cooperate a

times per revolution of this wheel with the upper half of the pi-

  gnon 41. Each of the pinions has 40 teeth, so that at the end of each revolution of the toothed wheel 35, the teeth 49 of

this wheel rotate the pinion 41 a fraction of a turn.

  Fig. 5 is a bottom view of the second toothed wheel 36. This wheel has eighty teeth 54, only six of which, indicated by the reference 54 ', have the total height of the toothed wheel. The teeth 54 have the same pitch as the teeth 49 and they are permanently engaged with the lower half of the teeth of the pinion 41 so that at each step or fraction of a turn of the pinion 41, the wheel

  tooth 36 and the corresponding ring 19 turn one tenth

me back. The lower half of the six teeth 54 'mesh with the upper half of the following pinion 42, half of which

  is permanently engaged with the upper part

of the next gear 37. This gear and

  also the toothed wheels 38 and 39 are identical to the wheel 37 except that their inner sleeves have smaller and smaller diameters. The toothed wheel 40, being the last and not having to cooperate with two pinions, has only

teeth of maximum height.

  Each of the toothed wheels 36, 37, 38, 39 and 40 is also combined with a corresponding spring pawl 55 which cooperates with the teeth 54 to align and maintain the corresponding toothed wheel and the corresponding encrypted ring.

  after each step ahead. These pawls 55 are vertically aligned

wedging below the ratchet 51 of the ratchet wheel 35,

  all pawls being mounted on the same axis.

Finally, to complete the description of the

mold structure, it should be noted that the half-mold

upper 1 is provided on its outer wall with a fork

  te 56 with two branches which extends generally in di-

  rection of the half-mold 2 but is inclined relative to the axis of the mold. As indicated in FIG. 6, the fork serves as an actuating member for the lever 53, and moves this lever to the left in a slot 57 in the crown 34 of the intermediate part of the half-mold 2 when the mold closes, and to the right when the mold opens. This has the effect that at each cycle of opening and closing of the mold, the ratchet wheel 35 rotates by a step of one of

his teeth 48.

We will now consider the operation of the mold in the position shown in FIGS. 1 to 6, that is to say while the mold is closed and the different imprints 4 have their parts 5 associated with. Numbers identical to

  those of the various rings 17 to 21 (0000000, 1111111, ... 9999999).

The injection of the plastic material takes place through the nozzle 6. The plastic material injected through the nozzle 6 is distributed along the ten radial channels 13 and through the throttles 14 to fill the ten cavities 4 and, by therefore, mold ten labels

numbered by combinations 0000000, 1111111, 2222222 ...

9999999. When the injection (not shown) separates the half-mold 1 from the half-mold 2 thereby allowing the conical element 25 (see Fig. 6) to protrude beyond the face

  of the half-mold 2, under the effect of the force of the res-

compression spell 27. This movement is limited only by the heads of the three screws 32 which abut against the bottom of the cavities

  33. Under these conditions, the rings 18 to 23, which are closed

due in 60 (Fig. 3), become relatively free and, in any case, capable of rotating relative to each other.

At the same time, during the opening of the mold, the

  vier 53 moves to the left under the action of the four-

  chette 56 (see Fig. 6), which advances the pawl 50 (Fig. 4) and rotates the ratchet wheel 35 by a tenth of a turn, that is to say by a tooth pitch 48 At the same time, the pawl 51 meshes with the next tooth 48 located on the other side of the wheel to retain it and prevent it from describing undesirable movements. This rotation of a tenth of a turn of the toothed wheel 35 also results in an identical rotation of the outer ring 18, so that the number

  0 of this ring advances to the imprint N'1, its number 1 advances

  this at footprint N02 and so on. The following combinations

  so will be 0100000, 1211111, 2322222, 3433333, 4544444,

5655555, 6766666, 7877777, 8988888 and 9099999.

  Just before the mold reaches its open position

  total green, the head 12a of the piece 11 abuts against a

fixed part of the injection machine, which pushes the plate

  that ejector holder 8 forwards, towards the working face of the mold, projecting the ends of the ejection pins 9 and 10 beyond the working face of the half-mold 2 to eject the parts mussels and carrots

for injecting the imprints 4 and the channels 13.

At the end of the closing movement of the mold, the fa-

  this working half-mold 1 strikes the conical element 25 and pushes it backwards by overcoming the elastic force of the spring 27 and making it resume the configuration of Fig.l. This expands or deploys the rings 18 to 23 ensuring that these rings are exactly fitted into each other without leaving spaces or gaps

  which would give rise to the formation of burrs during the

next jection.

  Until the tenth injection, i.e. until the number combinations reach 0900000, 1011111, 2122222, ... 9899999, the mold works

  just repeat. On the contrary, when the mold opens to-

  after the tenth injection, the rotation of the toothed wheel 35

(one tenth of a turn) makes the teeth 49 cooperate with the pi-

upper rod 41, which transmits the rotation of a tenth of a turn to the second toothed wheel 36. As a result, the ring 18 returns to its initial position and the next ring 19 is

  simultaneously set in motion to advance its figures

fres from one footprint to another; This means that the eleventh

  the injection will produce the following combinations: 0010000,

1121111, 2232222, 3343333..9909999.

Continuing injection cycles will therefore produce ten million combinations (from 0000000 to 9999999), without repetition and without giving the appearance of producing a

series.

  Although the mold mentioned above uses numbers on its marker rings 18 to 23, it goes without saying that

  is also possible to use letters or other ca-

identification characters. Furthermore, FIG. 3 shows a

  variant in which the ten digits are used alternately

  nance with the letters A, B, C, D, E, F, G, H, I and J. Consequently, it suffices to rotate the rings 18 to 23 with a small relative rotation by. compared to their respective cogwheels 35 to 40 and to replace the elements 17 by others bearing engraved letters to transform the combinations

  of numbers in combinations of letters.

  It is also evident that the number of footprints

tes 4 was limited to ten only because of the application to the decimal system. In an eighteen cavity mold, for example, it is possible to use rings carrying eighteen

  letters (from A to R), in which case the ratchet wheel 35 should have

seder eighteen teeth 48 while teeth 49 and gears 36 to 40 should be suitably coordinated to transmit from one to the other of the steps of an eighteenth

of turn.

  It would also be possible to produce the mold which has just been described with twenty imprints, the rings then carrying the alphanumeric engravings represented on

Fig. 3, so that all combinations of the ten let-

three and ten digits can be used without repetition

tion.

1 - Mold for compression injection molding

two half molds which separate after each operation

molding and have joint working faces

  fords delimiting between them a series of molding impressions and injection channels which open into these

footprints, this mold being characterized in that it comprises

  takes concentric rings (18 to 23) provided in

a first (2) half-mold, which can rotate

  reference axis turn perpendicular to said faces

  working (3) and form portions of said imprint

tes (4) at regularly spaced points around said

* reference axis, each ring presenting towards the interior

  laughter of each imprint a mark which is different from those which it presents to the other imprints, means (35 to 45) serving to rotate one of the rings

in successive steps so that its brands are pre-

felt one by one at said fingerprints and to rotate

  each of the other rings one step each time the year-

  previous round has completed a round, as happens

  in a mechanical counter, and operating means

ment (50,53,56) used to actuate said turning rings

  steps of each step of separation and reconciliation

the half-molds.

2 - Mold according to claim 1, characterized in that said concentric rings (18 to 23) are

adjusted and tight against each other when -

  the half-molds are close together and their surfaces of

  work (3) are in contact with each other.

3 - mold according to claim 2, character-

  se in that said rings (18 to 23) are expandable,

  these rings are in the expanded state when the fac-

these working half-molds are in contact with each other.

  4 - Mold according to claim 3, character-

  se in that said rings (18 to 23) are located

  the unexpanded state when the half-molds (2,1) are dried

  trimmed together, to facilitate rotation

relative of the rings.

13 2473948

- Mold according to claim 4, characterized in that it comprises means (24,25) serving to

  dilate the rings (18 to 23) when the half-slack

are brought together.

  6 - Mold according to claim 5, characterized in that said means serving to expand the

rings include an element (25) having the form

  me of a cone or truncated cone, centered on said axis of the mold and which forms the central portion of said first half-mold (2), the base or the large base of this element (25) constituting a part of the working face of the first half-mold, an inner surface

  conical (24) associated with the innermost ring (23)

  inside of said rings and which cooperates with the conical surface of the element (25) and elastic means (27) which tend to place this element (25) in a projecting position relative to the other portion of the surface

of the first half-mold.

7 - Mold according to any one of the claims

  cations 3 to 6, characterized in that each of the rings

  (18 to 23) is split so that it can expand.

  8 - Mold according to any desrevendica-

1 to 7, characterized in that it comprises ten em-

  preints (4) and that each ring has ten marks.

9 - Mold according to claim 8, character-

  laughed at in that the ten brands are represented by

the figures 0,1,2 ... 9.

  Mold according to any one of the claims

1 to 8, characterized in that the marks are represented by letters in numbers equal to that of the imprints.

  11 - Mold according to claim 9, character-

  marked in that the rings (18 to 23) bear ten other additional marks placed in the intervals which separate the figures, these other marks comprising letters, so that the mold can be used so as to present in the imprints, namely the figures ,

either the letters.

12 - Mold according to any one of the claims

  cations 1 to 11, characterized in that each imprint (4) has a fixed mark which differs from the mark

  of each of the other fingerprints.