SEALING SYSTEM, SECURITY SEAL AND INJECTION MOULDING SYSTEM FOR MANUFACTURING A SEALING SYSTEM

Abstract: A sealing system of the type in which a locking pin is received in a cavity containing a tooth that cooperates with the pin to prevent withdrawal of the pin. The object of the invention is to provide this type of seal but which is at the same time both of high security and simple to manufacture. In the system of the invention, the cavity (2) has two openings (14, 16) adjacent to each other and separated by the base (17) of the tooth (18). The cavity is otherwise totally closed and its inner wall (21), which extends to the bottom of the cavity, is curved under the base (17) of the tooth. This permits manufacture using an injection mould having a plate (39) provided with a fixed part (40) and a part (41) rotatably mounted on the fixed part to define therebetween the male mould portion for moulding a cavity with a tooth. An actuator (42) serves to rotate the rotary part (41) during opening of the mould, the rotary part (41) having a curved surface (52) corresponding to the curved part of the inner wall (21) of the cavity. Security seals and devices incorporating the new sealing system are also described.

Description: Title: "SEALING SYSTEM, SECURITY SEAL AND INJECTION MOULDING SYSTEM FOR MANUFACTURING A SEALING SYSTEM" The present invention refers to a new sealing system suitable for use in security seals and other devices designed to seal objects. Many sealing systems are known in which a locking pin is received within a cavity or orifice having internal teeth for cooperating with and locking the pin, thus prevent¬ ing relative movement between the two parts. However, many known drawbacks are associated with seals of this type, for example: a) although their manufacture is relatively simple, those systems that use orifices passing right through the part in which they are formed have a generally reduced degree of security since access to the teeth is available from the side of the orifice opposite that which is penetrated by the lock¬ ing pin; b) attempts to increase the degree of security of systems of type a) above often fail to provide the ideal secu- rity desired and almost always increase manufacturing costs; and c) those systems in which the bottoms of the locking pin receiving cavities are closed so as to prevent access to the pins after closure are manufactured using injection moulds having complex structures subject to all types of malfunction, this also increasing the cost of the final product to an inac- ceptable level. ' The purpose of the present invention is, therefore, to provide a high security sealing system that can be manufac¬ tured using an extremely simple injection mould that is not subject to malfunction. According to the present invention, a sealing system for a security seal is of the type comprising a first part having a cavity containing a tooth and a second part carrying a locking pin which, on being inserted into the cavity through an entry opening, cooperates in locking relation with the tooth to assume a sealed configuration that prevents its re¬ moval from the cavity. There is a second entry opening to the cavity adjacent the first entry opening and the region between the two entry openings comprises a base of the tooth. The cav- ity is substantially closed with the exception of the two entry openings and an inner wall of the cavity - which extends from the edge of one of the said entry openings to the bottom of the cavity which is opposite the entry openings - is curved under the base of the tooth. This novel sealing system is suitable for manufac¬ ture by injection moulding using a mould having a fixed part and a rotary part to mould the closed cavity with the inner tooth. This is possible precisely due to the novel character¬ istics of the sealing system, that is to say, the fact that there are two adjacent entry openings with the base of the tooth between them and that the inner wall of the the cavity is curved under the base of the tooth. With further reference to the sealing system, the tooth is preferably formed with a longitudinal slot and the locking pin has a longitudinal rib that fits into such slot in the sealed configuration. It is also preferable that the edge of the entry opening from which the curved wall extends is the edge of the second entry that is opposite the edge adjacent the base of the tooth. According to another aspect of the invention, a se¬ curity seal comprises a sealing system as defined above, an elongate flexible strip extending from the first part and formed along its length with a series of openings longitudinally spaced ftom each other, and hinge means joining the second part to the first part to permit the second part to be folded over the first part to present the locking pin to ^ the first entry opening of the cavity. Each of the openings in 5 the strip is dimensioned to permit passage therethrough of the i*. locking pin. In a preferred embodiment of the seal, there are guide means in the first part for passage of the free end of the flexible strip. Furthermore, the first part may be formed 10 with a protuberance adjacent one of the entry openings, the protuberance being dimensioned to penetrate one of the openings in the strip and being spaced from the first entry opening by a distance equal to the distance between the openings in the strip. 15 According to yet another aspect of the invention, a security seal in the form of a closure seal for sealing an opening in the end of a tubular member formed, in the proxim¬ ity of such opening, wit-i a pair of diametrically opposite openings, comprises a top panel and a cylindrical skirt 20 diametrically split into two halves hinged to each other along a vertical line at the division between the two halves of the skirt. An inner protuberance on each half serves for fitment into one of the pair of openings in the tubular member, so that the closure seal may be closed by articulation around the 25 end of the tubular member, axial movement in the closed posi¬ tion being prevented by the above mentioned fitment. The first and second halves comprise the said first and second parts of a sealing system according to this invention, with the cavity formed on the first half and the locking pin on the 30 second half on their respective vertical edges opposite the vertical hinge line so that, on closing the closure seal * around the end of the tubular member, the pin penetrates the cavity and seals the device. Other types of security seals and of devices that 35 have to be closed are also embraced by the present invention, provided that the new sealing system is used. In this respect, special attention should be given to the device for closing and sealing envelopes disclosed in Brazilian patent applica¬ tion PI 8903982 (and corresponding US 4,983,047) that could have its six ot more sealing systems substituted by the new system according to the present invention. Another seal comprising a sealing system according to the invention has the above mentioned first and second parts hinged to each other by two hinge lines separated by a portion having a dimension determining a separation between the first and second parts in the said sealed configuration. The first part is provided with an extension foldable over the cavity prior to closure of the seal and formed with an opening suitable to be penetrated by said locking pin but which is smaller than the first entry opening , such opening becoming aligned with the first entry opening when the extension is folded over the cavity. As already mentioned, the new sealing system is in- timately related to the fact that its manufacture may be fa¬ cilitated by a simple moulding process that is economic and highly reliable during prolonged operation. Thus, in accord¬ ance with another aspect of this invention, a moulding system in an injection mould for manufacturing the new sealing system comprises a mould plate mounting a first fixed part and a sec¬ ond movable part susceptible of movement comprising at least partial rotation between a first position in which the movable part cooperates with the fixed part to define a male formation for moulding a cavity with an internal tooth usable in the new sealing system, and a second demoulding position. It further comprises an actuator means adapted to cause movement of the movable part during an opening movement of the mould to permit demoulding. The present invention will be better understood from the following description given soley by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a security seal in accordance with a first preferred embodiment of the invention; Figure 2 is side view, partially in section, of the seal of Figure 1, showing the sealing system according to the invention immediately before use; Figure 3 is a view similar to that of Figure 1, but with the seal in the closed or sealed configuration; Figure 4 is a perspective view of a security seal in accordance with a second preferred embodiment of the in¬ vention, the seal being illustrated in position for sealing the end of a tubular element; Figure 5 is a top partially cut-away plan view of the seal of Figure 4 during closing; Figure 6 is a view sililar to that of Figure 5, but with the seal in the closed or sealed configuration; Figure 7 is a perspective view of a device for the closure and sealing of envelopes that incorporates various sealing systems according to the present invention; Figure 8 is a section through a plate of a mould, containing elements for moulding sealing systems according to the present invention; Figure 9 is a perspective view of two of the ele- ments shown in Figure 8; Figure 10 is a plan view of a further preferred em¬ bodiment of a security seal provided with a sealing system ac¬ cording to the invention, the seal being viewed in an open position; and Figure 11 is a cross sectional view along line A-A of Figure 10, except with the seal being prepared for closure. Referring now to Figures 1 e 2 of the drawings, they show a new security seal using a sealing system according to a preferred embodiment of the invention. The security seal co - prises a first part 1 provided with a capsule-like cavity.2 and a second part 3 integral with the first part 1 and hinged thereto about a hinge line 4 so as to be able to fold over and cover the cavity 2 in part 1. Part 1 of the seal comprises a flat base 5, in which cavity 2 is formed, two lateral flanges or guides 6 normal to the plane of the base and parallel to the side edges of the cavity and, at one end adjacent a first end of the cavity, a lateral strip 7 interconnecting corresponding ends of flanges 6 to define a passage 8. Adjacent the other end of cavity 2, base 5 is formed with a small rectangular protuberance 9, the function of which will be described later as will also an opening 10 cut into the end of part 3 and having one edge coinciding with hinge line 4. Part 1 is further provided with an elongate flexible strip 11 that extends from base 5 at a position adjacent pas¬ sage 8 and is formed with a series of rectangular openings 12 slightly larger than protuberance 9. Laterally of part 1 of the seal, there is an iden¬ tification tab 13. Considering now the sealing system in more detail, cavity 2 has an entry opening 14 for receiving a locking pin 15 formed at the end of part 3 that is remote from hinge line 4. Cavity 2 also has a second opening 16 adjacent to and in the same plane as entry opening 14, it being separated from the latter by the base 17 of a locking tooth 18 that projects into the interior of cavity 2. Tooth 18 is longitudinally split to form a double tooth, the distance between its free end and the bottom of cavity 2 being substantially the same as the axial dimension of a head 19 of locking pin 15 on part 3 of the seal. It will be observed that tooth 18 is inclined from its base 17 , partially under (as shown in Figure 2) entry opening 14 so that it presents a certain resistance to the complete insertion of the locking pin into cavity 2, after which - due to the resilience of the tooth - head 19 of pin 15 pass beyond the inner end of the tooth, a rib 20 along part of the length of pin 15 and immediately behind the head fitting into the slot defined by the longitudinal split in the tooth. In this manner, pin 15 becomes firmly caught in cavity 2 so as to exercise the locking function of the seal. Another important aspect of the seal according to this invention resides in the formation of the inner walls of cavity 2. It is that formation, combined with the localisation of tooth 18 between the two openings 14 and 16, that greatly facilitates the manufacture of the device (as will be de¬ scribed later) with a cavity having an internal tooth, that is totally closed with the exception of the two openings 14 and 16. It will therefore be seen that the cavity has two side walls normal to the plane of base 5 of part 1 of the seal, interconnected by a wall 21 that, as best seen in Figures 2 and 3, starts from an edge 22 of opening 16 and curves under¬ neath base 17 of tooth 18 to a point at the bottom of the cav- Figure 4, it may be placed around opening 30 and then closed so that the two protuberances fit into slots 32. The closure seal of Figures 4 to 6 is also provided with a sealing system almost identical to that of the seal of Figures 1 to 3. Thus the same characteristics are indicated with the same reference numbers. Half 26 of the seal is pro¬ vided with a lateral blade 33 formed at one end with a cavity 2 identical to that of the first embodiment, that is to say, it has entry openings 14 and 16, the split tooth 18 with its base 17 and the curved wall 21. The remaining part of blade 33 corresponds to the identification blade or tag 13 of the seal of the first embodiment. Half 27 of the seal is equally formed with a locking pin 15 with head 19 and a longitudinal rib 20, the only dif- ference being that the pin is connected to a small lateral blade 34 by means of a weakened region 35. Figure 5 shows closure seal 25 during closure while Figure 6 shows the seal in the closed or sealed configuration. It will be understood from the similarity to Figures 2 and 3 that closure of seal 25 is effected in a manner identical to that of the seal of the first embodiment described. Figure 7 shows another application of the sealing system described above, this time together with a device for closing and sealing envelopes. This device will not be de- scribed in detail since, with the exception of the sealing systems, it is identical to that described and illustrated in Brazilian patent application PI 8903982 of 08.08.89 (corre¬ sponding to US 4.983.047) of the present applicant and which is incorporated herein by way of reference. The envelope clo- sure device 36 shown in Figure 7 comprises one half 37 folded over another half 38, the two halves being sealed together by six sealing systems. In the case of PI 8903982, each sealing system comprises a locking pin upstanding from the half corre¬ sponding to half 37 and intended for being received in an orifice having internal teeth in the other half. In the device of Figure 7, each pin (not visible) in half 37 is identical to pin 15 in Figure 1 and each orifice with its internal teeth is substituted by a capsule type cavity identical to that used in the other embodiments of this invention. Apart from ensuring a

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CN g • H o O 44 g o 13 CN 13 01 3 o c 44 •H 44 Φ o Φ c 44 c ^ IH 4-! 44 tH o id Φ rd 14 c 44 ft o o > Φ 44 o σ. o U ■ri o O φ id c ft 01 O Φ o IH i φ φ 44 o id cn id cn G 01 φ fi ■ H id Φ 44 o m CJ- xi φ 01 C cn 44 -P 43 4 01 14 Φ o φ ϋ fi o fi Φ Eh 01 01 ft XJ Eh rd -P o Φ fd Φ 44 3 3 43 J- 01 01 •H ft 01 c 44 cn 01 rd 13 g 44 Φ g 44 01 44 c 44 13 44 01 φ •H G 13 cn • r-i .H 14 o 01 IH V-l id o φ o 13 •H O !H O cn 13 o g 13 - > •H CO rd 13 id φ 14 3 Φ 44 43 44 Φ id C id id O Φ H G fi 3 •H fi H id Φ rd ft id n 01 44 13 01 43 13 4 fd ft -P O 43 ft rd ft 01 H > J ft •H id 44 13 o — O 43 0] O co opening (14') when ≤aid extension (61) is folded over said cavity 9. Moulding system in an injection mould for manu¬ facturing a sealing system as claimed in claim 1, 2 or 3, characterised by comprising a mould plate (39) mounting a first fixed part (40) and a second movable part (41) suscepti¬ ble of movement comprising at least partial rotation between a first position in which said movable part (41) cooperates with said first fixed part (40) to define a male formation for moulding a cavity with an internal tooth usable in a sealing system as claimed in claim 1, 2 or 3, and a second demoulding position, said movable part (41) having a curved surface por¬ tion (52) corresponding to said curved part of the inner wall (21) of the cavity (2) of said sealing system; and an actuator means (42) adapted to cause the said movement of said movable part (41) during an opening movement of said mould to permit demoulding. 10. Moulding system according to claim 9, characterised in that said movable part (41) is rotatable through a limited angle about a fixed point with respect to said first fixed part (40). 11. Moulding system according to claim 10, characterised in that said first fixed part (40) and said sec¬ ond movable part (41) are provided with mutually cooperable articulation means (44,43) about which said movable part (41) may execute its said limited rotation with respect to said fixed part (40). 12. Moulding system according to claim 9, 10 or 11, characterised in that said actuator means (42) is spring bi- ased to maintain said second movable part (41) in its said second demoulding position and linear movement of said actuator means (42) causes said second movable part (41) to move to said first position. 13. Moulding system according to claim 12, characterised in that said linear movement of said actuator means (42) causes said second movable part to undergo a par¬ tial rotation about a fixed point relative to said mould plate (39).

Inventors: DE LIMA CASTRO NETTO EDUARDO D, DE LIMA CASTRO NETTO, EDUARDO DE
Applicants: ELC PROD SEGURANCA IND, LIMA CASTRO NETTO EDUARDO DE D, ELC PRODUTOS DE SEGURANCA INDUSTRIA E COMERCIO LTD
Application year: 1993
Main classification: B65D55
IPC codes: B29C45, B65D55, B65D77, G09F3