FR2612117A1 - METHOD AND APPARATUS FOR ENCLOSING RINGS, BRACELETS AND THE LIKE IN A BODY OF TRANSPARENT PLASTIC MATERIAL - Google Patents

Abstract

THE PROCESS AND THE APPARATUS DESCRIBED PROVIDE FOR A RING 27 TO BE PLACED BETWEEN TWO PRESSURES 3A, 4A, IN THE FORM OF TWO HALF-MOLDS 3, 4 ASSOCIATED WITH AN INJECTION PRESS. THE SETTING OF THE RING TAKES PLACE BY SUPPORT ELEMENTS 14, 15 SLIDING ENGAGED THROUGH THE SAID HALF-MOLDS 3, 4. THE HALF-MOLDS ARE CLOSED TO ONE ANOTHER, SO THAT THE RING IS CONTAINED IN A CAVITY 5, DEFINED BY THE SAID PUNCHES 3A, 4A, INTO WHICH THE TRANSPARENT PLASTIC MATERIAL IN A LIQUID STATE IS THEN INJECTED. WHEN THE PLASTIC MATERIAL IS NOT YET COMPLETELY SOLIDIFIED, THE SUPPORT ELEMENTS 14, 15, CONTROLS FROM THE EXTERIOR OF THE RESPECTIVE HALF-MOLDS, ARE REMOVED FROM THE RING 27 WHICH REMAINS SUSPENDED IN THE PLASTIC MATERIAL. THE PLASTIC MATERIAL CONTAINED IN CAVITY 5 IS AFTER COMPRESSED AND FINALLY COOLED UNTIL ITS SOLIDIFICATION. WE OBTAIN A RING ENGLOBATED IN AN ANNULAR PLASTIC BODY WHICH SHAPES THE SHAPE OF THE RING ITSELF.

Description

- 1 7

  The present invention relates to a method and a

  apparatus for including rings, bracelets and the like

  laires in a transparent plastic body and it is especially applicable in the field of jewelry and imitation jewelry. The present invention

  also relates to the product obtained by the men-

mentioned above.

  We know that there are methods by which a stone or the like can be included in a material

  transparent plastic in order to obtain aesthetic effects

  special ticks on the finished product, normally obtained

  naked as a result of other body finishing work in

plastic material.

  These methods essentially provide for the object to be placed on the mass of molten plastic and

  dropped into it by gravity.

  More particularly, taking into account the temperature

  solidification of the molten plastic and the weight of the stone, we manage to calculate the time

  necessary for the latter to dive deep

  predetermined deur inside the plastic material, normally up to half of the object which one wishes to obtain before the plastic material, while cooling, solidifies in a stable way, which allows the stone

  to stay there for good.

  The methods of the type described involve long working times, necessary for the slow cooling and solidification of the plastic to take place. It should also be emphasized that the known art has many limitations compared to the types of objects which

  can be encompassed and to the body conformations in ma-

-2-

  plastic that can be obtained. More particularly

  These are only very simple objects, such as stones, which can be included in

  plastic bodies which must be of

  also elementary geometric guration.

  Because of the problems described above, the methods

  according to the known art do not allow to include rings, bracelets and the like in plastic bodies

of similar configuration.

  In this situation, the main object of the present invention is to solve the aforementioned drawbacks by

  a process and apparatus by which one can

  quickly and precisely spheres rings, bracelets and the like in transparent plastic bodies having

the desired configuration.

  This goal and others, which will emerge more clearly.

  In the course of this description, are es-

  substantially achieved by a process for including rings, bracelets and the like in a transparent plastic body, characterized in that it comprises the following stages: - placing of a ring on support elements

  sliding through half molds

  pectives protruding into reciprocal depressions-

  opposite, formed in the half-molds; - reciprocal bringing together of the half-molds;

  - injection of the molten plastic material in the -

so-called depressions;

  - release of the ring from the support elements by the

  ring housing of the latter;

  - compression of the plastic in the pushers -

  ment; - 3 - - cooling of the plastic material until it solidifies; - reciprocal spacing of the half-molds and removal of these from the semi-finished product obtained; - removal of excess plastic by drilling in the area circumscribed by

the ring in the product obtained.

  According to the invention the method described above is implemented by an apparatus capable of including rings, bracelets and the like in a transparent plastic body comprising a mold composed of at least two half-molds capable of approaching one on the other and provided with respective depressions in defining form, when the

  half-molds are brought together, a cavity having the shape of the

  said plastic body, closing means capable of bringing said reciprocals closer and further apart and injection means intended to send plastic material into the mold cavity, characterized in that it comprises a plurality of support elements slidably engaged through the mold halves and control means for alternately reciprocating the support elements from a position of

  rest in which the support elements have their ex-

  respective grip hoppers hidden in the corresponding half-molds, in a working position in which said grip ends protrude from the corresponding half-molds in said recesses for the purpose of

  supporting said ring in a removable manner.

  Still according to the present invention, by the process

  dice and the apparatus described above can advantageously

  Obtain an annular transparent plastic body, characterized in that it contains a -4-

a ring inside.

  Other characteristics and advantages of the invention

  will be better understood from the detailed description which follows

  of a method and an apparatus for including bat-

  gues, bracelets and the like in a trans parent plastic body, made with reference to the appended drawings, given by way of nonlimiting example, in which: - Figure 1 is a schematic and partially uninterrupted section of the apparatus in question, executed along line II of Figure 2;

  - Figure 2 is a front view, schematic and inter-

  broken, of the apparatus shown in Figure 1;

  - Figure 3 is a schematic section showing the par-

  essential parts of a drilling unit forming part of the apparatus in question;

  - Figure 4 is an elevational view of an enclosed ring

  open in a transparent plastic body according to the present invention.

  Referring to the figures cited, we have generally

  diqué en 1 an apparatus able to include rings, bra-

  celets and the like in a plastic body.

  With particular reference to Figures 1 and 2,

  the apparatus 1 comprises a mold 2 associated with a pressure

  se of known and conventional injection, from which we have illustrated only certain parts which will be taken into

  consideration individually during the description.

  The mold 2 essentially consists of at least one

  first half-mold 3 and a second half-mold 4 above-

  capable of approaching one another and provided with respective sockets 3a and 4a of symmetrical shapes, so as to define, when the half-molds are brought together, a cavity 5 of suitably shaped annular configuration. The reconciliation and reciprocal spacing of the half-molds 3 and 4 is obtained by closing means 6 partially shown and forming part

  of the aforementioned injection press. The means of iron-

  procedure 6 comprise a first support member 7 and a second support member 8 reciprocally opposite,

  fixed respectively to the mold halves 3 and 4 and mobi-

  them so as to come closer and separate one of

  the other in a known and conventional way.

  The press with which the mold 2 is associated is in

  additionally provided with injection means, partially

  shown, which send the plastic in the liquid state into the cavity 5 when the half-molds 3 and 4 are

  close together. Sending plastic material

  that in the cavity 5 takes place through an injector tube 10 which

  passes through the first support member 7 and the first half

  mold 3 and is provided with a supply line 10a through

  which the material to be introduced into the cavity 5 is

  seen. It can easily be seen in FIG. 1 that the supply pipe 10a has a diverging frustoconical shape

  towards the second half-mold 4, and it is in com-

  munication with the annular cavity 5 through a passage zone 11 which is defined between the half-molds 3 and 4 when the latter are brought together, as

as shown in Figure 1.

  A guide sleeve 12 is rigidly introduced into the half-mold 4; is is next to the inlet tube

  , in correspondence of the passage zone 11 and presents

  te a housing 12a of frustoconical configuration conver-

  giant towards the ejector tube. A pushing element 13 acts in correspondence with the housing 12a; it crosses - in a sliding manner the guide sleeve 12 and the second support member 8. The pushing element 13 acts on

  order of known means contained in the press

  jection, so as to cause, as will emerge more

  clearly thereafter, the release of the parts produced

  tes in the mold 2. When the mold 2 is closed, the pushing element 13 returns to the position shown in FIG. 1 thanks to the return rods 9 which are

  linked to the latter in solidarity and which cross-

  slidingly feels the second support member

  8, on these rods abutting the first support member

port 7.

  According to the present invention, a plurality of pre-

  first support elements 14 and a plurality of second-

  my support elements 15 are associated respectively

  with molds 3 and 4. The first and second elements

  supporting elements 14 and 15 pass through

  health the corresponding half-molds 3 and 4 and each have

  their respective grip end 14a, 15a located near

  mite of the corresponding depression 3a, 4a. As can be seen in FIG. 2 in which the first half-mold 3 and the parts which are directly associated with it have been shown from the front, it is provided that four support elements 14, 15 be associated with each of the half-molds 3 and 4; these support elements are distributed circumferentially around a common axis which coincides with the axis of the injector tube 10 and have a configuration

  laminar oriented radially with respect to the pre-

  cited. Advantageously, the grip ends 14a of the first support elements 14 are chamfered on

  their edge disposed on the side opposite the axis of the tube

  jector 10. The plug ends 15a of the second

  support elements 15 have a straight profile.

  -7- Control means generally indicated at 16 act on the first and on the second support elements 14 and 15 in order to move them simultaneously

  relative to the half-molds 3 and 4 from a position of re-

  pos, in which the grip ends 14a and 15a are hidden inside the mold halves 3 and 4, at a

  working position in which the pri-

  protrude inside the respective recesses

3a and 4a.

  These control means 16 comprise, by each of the half-molds 3 and 4, a mobile support 17 disposed in a lo

  gement 18 formed in the respective half-mold 3, 4, the-

  which rigidly engages the respective support elements

  14, 15. The mobile supports 17 are engaged respectively-

  slidingly along the ejector tube 10 and along the pushing element 13 and are actuated by respective control levers 19 according to a movement

  spacing and approximation to the cavi-

  tee 5. Each control lever 19 is pivoted at 20 on the respective support member 7 and 8 and has a fork portion 19a, best represented in the figure.

  2, which extends along the housing 18 for engagement

  manage the respective mobile support 17 in correspondence with a groove 17a formed on the circumference thereof (see

Figure 1).

  Global drilling means are also provided.

  ment indicated at 21 in FIG. 3, acting in a manner

  re to eliminate the excess parts of the demolded products

  the. It is preferable that the drilling means 21 form a separate unit from the injection press to which

- 8 -

mold 2 is associated.

  In an original way, the drilling means 21 corrpor

  tent a support base 22, rigidly engaging at a part

  fixed tie of a not shown column drill being known and conventional, and a cutter 23 provided with a

  tail 23a which allows its connection to the pin of the

above mentioned.

  In an original way, the support base 23 is provided

  a through hole 24 with a vertical axis and a push-in

  25 lying around the hole 24 and having a configuration

  ration similar to that of recesses 3a and 4a. The cutter 23 advantageously has a closed tubular configuration on the side of the shank 23a, arranged coaxially by

  relative to the through hole 24 and having an outside diameter

  slightly smaller than the diameter of the through hole.

  The milling cutter 23 is provided with a front toothing 26 distributed

  circumferentially fogging on its end in

look of the support base 22.

  Having described the apparatus in question from a particularly structural point of view, its functioning,

  according to the method of the present invention, is as follows.

  If it is assumed that the preheating of the abovementioned injection press has already been carried out, the working cycle of the apparatus 1 provides that the mold 2 is placed open with the half-molds 3 and 4 spaced apart from each other and that the support elements 14 and 15 are in their

working position.

  After that the process first provides for the placement

  ce of a ring, indicated at 27, on the gripping ends 14a of the first support elements 14. In the example described here, provision is made for the ring 27 to be produced

  in gold, a material whose physical characteristics

  -9- are particularly concerned with the implementation of the process

of the invention.

  After the engagement of the ring 27 on the support elements 14, the mold 2 is closed by bringing the support member 7 closer to the support member

  8, which consequently leads to reconciliation

  near half-molds 3 and 4. In this situation the

  grip ends 15a of the second support elements

  yours 15 come into contact with the ring 27 and fix their positioning in the cavity 6 in opposition to the

first support elements 14.

  The injection of the plas-

  transparent tick in the liquid state in the supply line

  conducted l1a obtained in the injector tube 10. The molten plastic material is distributed homogeneously in the mold 2 and fills the passage area 11, the cavity 5

and the housing 12a.

  The transparent plastic material used can be

  advantageously polycarbonate or polymethyl methacrylate.

  In the example taken into consideration, provision is made for the plastic to be heated by known means contained in the injection press, so as to have

  a temperature between 255 and 295 C in corresponding

  dance of the injector tube 10 and that it is injected at a

  pressure between 20 kg and 30 kg. The injec-

  2 cm2 of the material should preferably be

  a speed of about 0.8 cm per minute per second,

during a period of 3.5 seconds.

  After this time has elapsed there is the release of the ring 27 from the support elements 14 and which are brought to the rest position by the levers

  19 which can be operated automatically-

- 10 -

  or manually. In this situation the ring 27 remains suspended in the plastic which has a density high enough for displacements of

the ring does not occur.

  Immediately after the above-mentioned release, the plastic present in the injector tube 10 and inside the mold 2 is compressed to a pressure ranging from

  kg to 30 kg, for a period of approximately 3.8 sec-

  cm2 cm2 condes. This compression step advantageously causes

  the elimination of the slots previously produced in the ma-

  plastic part by the plug ends 14a, 15a

during the injection stage.

  There is now a step of cooling the plastic inside the mold 2, so as to cause the solidification of the plastic. This

  the cooling step takes place allowing it to remain,

  over a period of about 20 seconds, the plastic material

  that and the ring 27 in the mold 2 which is maintained at a

temperature between 100 C and 120 C.

  The support member 8 is then moved away from the support member 7, which causes the opening of the mold 2. In

  this situation the semi-finished product obtained from pre-

  cédentes of molding is separated from the first half-mold 3 to be then finally demoulded under the action of the pushing element 13 which causes its forced release

of housing 12a.

  During demolding, the semi-finished product has different parts of surplus plastic, due to the solidification of the plastic present in the passage zone 11, in the supply line 10a and

  in the housing 12a during the above cooling.

  The configuration of the semi-finished product during demolding is

- i1 -

  clearly visible in Figure 3 o the semi-finished product has

  been shown, in broken lines, in cross section

  trale and indicated overall at 28.

  The elimination of the surplus parts of the semi-finished product 28 is obtained by drilling means 21. In more detail, it is provided that the semi-finished product 28 is positioned on the support base 22 according to what has been put in evidence

  in FIG. 3. The cutter 23 is then lowered di-

  rection of the support base 22, so as to cause the per

  lapping of semi-finished product 28 within a circumscribed area

  written by ring 27. The particular structure of

  drilling means 21 according to the invention advantageously allows-

  ment the execution of a very precise drilling following the-

  which one obtains a waste 28a which is moved away by fall to

through hole 24.

  After performing the drilling, the product obtained can be subjected to finishing operations, carried out

  in a conventional manner and known per se, in order to obtain

  nir, by sanding, the elimination of any roughness

still superficial.

  Advantageously, as visible in FIG. 4, at the end of the process described, the ring 27 appears to be encompassed

  in a perfectly transparent plastic body

  annuity, indicated at 29, of annular configuration, which reproduces the shape of the cavity 5 formed in the mold 2. Obviously, if we give different shapes to the cavity 5 we can obtain several conformations of the annular plastic body 29 which can be chosen according to the type of ring, bracelet or similar which must be included, as well as according to the aesthetic effect

that we want to reach.

The invention reaches the target markets.

- 12 -

  By the apparatus and the method described, it is indeed possible to quickly and according to a precise and predetermined positioning, include rings, bracelets and

  similar in a plastic body of suitable conformation

  nable. Obviously, numerous modifications and variants can be made to the present invention, without

  as far away from the framework of the concept that characterizes it.

  In particular, the data provided in relation to the

  peratures, pressures and times for the execution of the molding operations can vary according to the

  materials used, as well as dimensions and sizes

my product to get.

  The process in question can also be advantageous.

  sement employed in order to encompass any object which does not have an annular configuration while always obtaining, compared to the known art, several advantages with regard to production times and variety of forms

  which can be given to the plastic body.

- 13 -

Claims (12)

R E V E N D I C A T I ON S   1. Method for including rings, bracelets and   similar in a transparent plastic body   te, characterized in that it comprises the following stages: - placing of a ring (27) on support elements   (14, 15) which slide halfway through   respective molds (3, 4) projecting into recesses   mutually opposite cements (3a, 4a) formed in the half-molds (3, 4); - reciprocal bringing together of the half-molds (3, 4); - injection of the molten plastic material into said recesses (3a, 4a); disengagement of the ring (27) from the support elements (14,15) by the spacing of the ring from the latter;   - compression of the plastic in the pushers -   elements (3a, 4a); - cooling of the plastic material until it solidifies;   - reciprocal spacing of the half-molds (3, 4) and remove-   of these semi-finished products (28); - elimination of the surplus plastic material by the execution of a drilling in the zone circumscribed by the ring in the product obtained.   2. Method according to claim 1, characterized in that, after said step of removing the material in   surplus, we carry out a finishing operation of the pro-   duit obtained by sanding the surfaces of the transparent plastic body. 3. Method according to claim 1, characterized in that during the injection step the plastic material in the liquid state is injected at a temperature between 250Wp and 295 C, at a pressure between - 14 -   kg and 30 kg cm2 cm2 4. Method according to claim 1, characterized in   that the half-molds (3, 4) are kept at a temperature deletion from 100 C - 120 C.   5. Method according to claim 1, characterized in   that a period of 3.5 seconds has elapsed since the   from the injection stage to the degassing stage   gement of the ring (27) of the support elements (14,15).   6. Method according to claim 1, characterized in that the compression step is carried out during a period of 3.8 seconds.   7. Method according to claim 1, characterized in   that during the compression step the plastic material   that is compressed to a pressure between 10 kg and 30 kg cm2 cm2 9. Method according to claim 1, characterized in that said cooling takes place for approximately seconds.   9. Method according to claim 1, characterized   in that the plastic is polycarbonate.   10. Apparatus for including rings, bracelets   and the like in a transparent plastic body,   taking: - a mold (2) composed of at least two half-molds (3, 4) capable of approaching one another and provided with respective recesses (3a, 4a) in shape defining, when the half -moulds (3, 4) are brought together, a cavity (5) having the shape of said plastic body; closing means (6) capable of bringing said semi-molds (3, 4) closer and further apart; - injection means (10, 10a) intended to send plastic material into the cavity (5) of the mold (2), characterized in that it comprises: - 15 -   - a plurality of support elements (14, 15) slidably engaged through the half-molds (3, 4);   - control means (16) for moving alternative-   back and forth the support elements (14, 15) from a rest position in which the support elements have their respective gripping ends (14a, 15a) hidden in the mold halves (3, 4) corresponding to a working position in which said ends of   socket (14a, 15a) protrude from the corresponding half-molds   dants (3,4) in said recesses (3a, 4a) for the purpose of removably supporting said ring (27); and   - drilling means (21) intended to eliminate par-   excess product (28) removed from said mold (2).   11. Apparatus according to claim 10, characterized in that said control means (16) comprise, by each of said half-molds (3,4), a movable support (17) which are rigidly engaged the respective sou elements   yours (14,15), slidingly guided according to a movement   spacing and approximation of said recesses (3a, 4a) and actuated by a pivoted control lever (19)   on an integral part of the corresponding half-mold.   12. Apparatus according to claim 10, character-   laughed in that said support elements (14, 15) are distributed circumferentially around an axis   common and have a radially oriented laminar configuration   relative to said common axis.   13. Apparatus according to claims 10 and 12,   characterized in that the grip ends (14a, 15a) of the support elements (14, 15) corresponding to at least one of said half-molds (3, 4) are chamfered on their respective edges arranged on the side opposite to the 'common axis. - 16 -   14. Apparatus according to claim 10, character-   laughed in that said drilling means (21) comprise a support base (22) provided with a through hole (24) vertical around the top of which extends a recess (25) of configuration equal to that of the recesses (3a   and 4a) formed in the half-molds (3, 4), and a   se (23) of tubular conformation arranged coaxially with respect to the through hole and provided with a front toothing (26) distributed circumferentially on its end opposite the support base (22), said support base (22) and said cutter (23) can be   fixed respectively to a fixed part and to a pin- che of a drill press.   15. Body of transparent plastic material of annular shape, characterized in that it contains a ring with its interior.