BE643286A - - Google Patents

Description

       

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 i a 1 y 1 T U '1 H V 1 H T tON. Mr. UlRUHMAN5 Antoine, kNGGiDE Dit aOUUURI 10ü riuw 'üxili0i18TIQaiN n ... rr * aw, .wWrwwrsir.nww.rl.ri.rwwwlrWwwllwwr11. The invention relates to a process of shearing or said welding and simultaneous cutting of thin films Thermoplastic materials such as, for example,
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 pollétbl1ne, the pollproP1ln .. the Po latyrene and would interfere with any. thermoplat1qu materials.

   I.p 014 .. to the manufacture of objects. such as 8aC 'and packaging or protection sccbeta, pouches, cases, glove and extra, obtained in whole or in part by superimposition and welding together of two or more excavated of said thermoplastic materials.
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 rlus apúc1alenent, the invention relates to the welding process consisting in exerting on the threads to be welded together a greater or lesser pressure for a more or less long time by means of one or more bars, knives or heating wires or heated so as to obtain the welding of these films together by local softening or melting along determined lines or profiles, with or without simultaneous cutting by melting and or crushing of said films by said bars,

   the so-called knives or heating wires.

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 more especially still, the invention relates to obtaining from continuous strips or sheaths. of thermoplastic material of objects such as bags, pouch *, cases, ganta and other objects more or less the like ..



  A known method consists in causing the bands or the sheath to be driven at Boude, by a mat * conveyor stopping bands or the ga making Ion stopping periods held bar a knife or a heating or heated film is applied to the material to be welded by a movement appreciably parpendioulair on the surface of the conveyor and withdrawn before the restarting of the latter, The welding can affect a simple shape such as one or more straight lines (bags) or on the contrary follow a more or less complicated profile ( ganta). The weld can be non-cutting (for example compartmentalization of a continuous sheath) or cutting (cutting of a sound in separate bags without waste or cutting of a profile such as a glove with separation of the waste).

   



   A disadvantage of this process is the loss of time resulting from stopping and restarting the conveyor each weld. Another disadvantage is the high price of the conveyor belt which must be able to withstand high local temperatures *
Another drawback is the difficulty of manufacturing a conveyor belt exhibiting no unevenness of thickness, in particular at the joint, an unevenness preventing regular welding and / or complete cutting of the object to be manufactured, which can lead to the rejection of a significant percentage of these objects.

   Another drawback is the need to frequently clean the conveyor belt where the material to be welded tends to become encrusted, in particular during simultaneous welding and cutting. Another drawback is the fragility of the conveyor belt, the surface of which deteriorates on contact with the heated knives and during frequent cleaning.



   Another disadvantage is the waste of time caused by frequent cleaning of the conveyor belt.

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   Another disadvantage is the impossibility of making the weld elsewhere than on the conveyor itself as a result of
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 the tendency of th rnt0pla <tiqu <x materials to adhere to their support after welding, another drawback. in the period of sharp welds is the tendency of <hardness <to be unreliable by shine. of the simply perpendicular movement of the knife vii-i -vi8 of the Support and because of the too short contact temple if one wishes to obtain high production rytg: eo.



   One of the aims of the invention is to obtain
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 Nûudupwtt raridra ranr peri. de ttmpa dut k ua <acuv <mMt lntermitttnt de IA mnt1br .. Another object of the invention is said to be able to make the eouduywt even of pïôfili aompliqudii tA outside the conveyor, which allows the use of coutto 88 boa walking in mqtdt1ux triiditionnelol eliminates the inconvenience of belt thickness inda.itce and avoids rejectlone in receding, avoids frequent cleaning of the belt as well as the loss of time and resulting wear avoids the encrustation of the material to be welded in the belt *
Another object of the invention is to obtain stronger welds while increasing the rate of
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 production, A Bouder machine and in application the principles of the invention most often involves three parts.

   or devices corresponding to three distinct functions which are also found in any existing intended machine.
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 at the same ut3elees These three parts are 1 In) The nlimontation or device having the function of bringing the sheets or the plastic sheath to the welding members.



  2) The actual welding devices. 2) The ejection or device whose function is to lead the soldered objects and, possibly the waste to the exit of the machine, It should be noted that, if the functions of the three parts of the machine are quite distinct, tell them
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 pnrtiaa can neanmolna include commuas organs. Thus for example, a belt conveyor can be used for @ feeding while extending into the welding part @ where it will serve as a support on which the welding will be done. @
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 The same may apply to the ejection conveyor.

   Finally, one end and the same conveyor can be extended into the three parts of the machine. Any other part of the machine can be common to two of the parts or to all three parts of said machine.

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   The present invention relates to the second of the parts listed above, to having the actual welding organs *. The other two parts, namely the feeding and the ejection, can include / understand generally any device @, distinct or not physically distinct from the actual welding members, without the principles of the invention being able to find me in any of these. modified.

     vans a machine conforming to the principles of the invention the welding between two or more sheets of thermoplastic material, 'obtained by squeezing more or less strongly said sheets between, on the one hand, a bar, a knife, a wire or any other suitable heating or heated object and, on the other hand, a support or welding base, which support can be a conveyor belt, a roller, a plate or any other suitable object, but with this new characteristic that the hot piece performs , during its contact with the sheets L weld and share with the said sheets a more or less pronounced angular movement,

   while in existing machines the hot part comes into contact with the sheets to be welded at an angle close to 90 and remains practically motionless with respect to said sheets throughout the duration of the weld, that is to say of contact with said leaves.



   A first intrinsic advantage of the angular displacement of the bending part during the welding is a local lami nage which, in addition to the effects of heat and pressure, favors the interlacing of the chains of molecules of the thermoplastic material and consequently improves the strength of the weld. In the particular case, the most frequent, where the hot part is both welding and cutting a second advantage intrinsic to the angular displacement of said part is to cause a safer and more complete separation of the parts welded and cut as a result of the existence of a rolling zone with zero thickness, zone the lnrwidth of which is added to the simple cutting effect and, where appropriate, to the effect of separation by fusion.



   However, this second intrinsic advantage offers its maximum effect when the axis of angular displacement of the welding and cutting part relative to the material to be welded merges with the cutting line * Said advantage decreases when the axis of said angular displacement forms an angle with the line of cut and said advantage disappears when said angle reaches 90.

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   To illustrate these advantages, FIG. 1 represents, in section and greatly magnified, the simple, non-cutting welding of two sheets of thermoplastic material (1) (2) welded by a hot part (3) undergoing an angular movement of the position (4) to position (5),
Note the rolling zone (6), Figure 2 represents, in section and greatly magnified, the weld-cut sheets (I) to (2) by means of a heating wire (7) undergoing an angular movement of the position (8) to position (9). Note the zero thickness rolling zone (10) added to the melting zones (11) a (12).



   Figure 3 showing * in section the essentials of a complete machine constituting one of the possible applications of the invention. plastic sheet eyes (1) Ó (2) from rolls ($ 1) *. (14) are driven by a conveyor belt (15) made of silicone rubber in a continuous movement in the direction of the arrow (16).



   A heating electrode formed by a wire (17) stretched over a non-combustible insulating part (18) pivots freely around an axis (19). This electrode occupies, when it is not in contact with the plastic, a vertical position shown in solid lines and limited by a stop (20) against which it is returned by gravity. The axis (19) is subjected (for example by a cam or pnr an electromagnet not shown) to a reciprocating vertical movement periodically pressing it against the plastic, which is itself supported by the conveyor (15) resting on a support roller (21). As soon as the electrode is pressed, the process of melting and hardening. plastic is primed.

   But concurrently, as a result of the uninterrupted movement of the belt, the electrode, while separating the plastic, initiates a pivoting movement around its axis (19) to take, when it is about to be raised, the position shown in dotted lines. returning to its ascent, being released, it resumes by gravity its vertical position and the cycle begins again.



  The parts welded and detached from each other (22, 23 etc.) continue to travel with the belt and leave the machine bare end thereof.

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   Two auxiliary conveyors (24,25) ensure the correct drive.



   Here appears a third advantage, not intrinsic to the invention, but made possible by it: the continuous movement of the belt and of the material to be welded saves the stopping time necessary for a non-electrode welding. swivel.



   A fourth non-intrinsic advantage is the absence of jolts of inertia allowing the construction of a machine that is lighter and therefore less bulky and less expensive.



   Figure 4 shows in section the diagram of another machine according to the principles of the invention. The rotating electrode has been replaced by a rotating electrode (26).



  This solution has the same advantages as the swivel electrode. In addition, it allows the realization of continuous movement of absolutely any profiles (for example gloves), which constitutes a fifth non-intrinsic advantage.
The electrode, both swiveling and rotating, can also rest, not on the conveyor belt, but on a separate roller. This possibility has been shown in Fig. (4) where the part of the belt which can be removed has been drawn in dotted lines.



   The welding is then done on the support roller (21).



  From this arrangement results a sixth advantage: the elimination of the silicone belt, excessively expensive and fragile, and whose joints, always unequal, cause significant waste in production. In addition, the loss of time due to frequent cleaning of the belt and its possible replacement are also eliminated. FIG. (5) shows the rotating electrode (26) seen perpendicular to its axis. It consists of a cylinder of insulating and incombustible material (27) on which is fixed a wire (28) heated by the passage of an electric current and matching the profile to be produced by welding (here a glove).

   In conclusion it is possible, by the application of the principles of the invention, to construct at a much lower cost, machines performing better welds at a higher rate, with less downtime and less waste.



   The description of the invention as it appears above has been given exclusively by way of non-limiting example as to the principles and the scope of said invention, which are clearly reproduced, explained and delimited in the claims below. .


    

Claims (1)

EMI7.1 R SVBN J3I ÇA TOJMJ, I, 'ood4d de icudura, eu de it11A11i and de 4'.op. a3mdlndea of excavation iapecrlui at the iSpifi dlîkûo tu of several bars, knives or dfliultli line where 6ctuff $ & characterized Oh and that during the time of application1i8 "10A of lot pressure exerted on said bars, said knives or heated or heating lines on the sites thermoplastic sheets, said barred or said heated or heated knives or fila are subjected in whole or in part with respect to the surface of said thermoplastic excavations to a more or less significant angular movement Belon un EMI7.2 common axis or parallel to all or part of the weld line * 2. Process for the simultaneous welding or welding and cutting of thermoplastic sheets according to claim 1, characterized in that said thermoplastic sheets move in a uniform and uninterrupted movement while a bar, knife or wire is heated. EMI7.3 or rectillene heater rotatable 1-wtt axis density by an angle about an axis parallel to the weld line said axis being distinct from said line, is EMI7.4 vdriodically applied by pressure against said sheets for a certain time during which said bar, said knife or wire is driven in the translational movement of said sheets to then resume EMI7.5 an initial position when said pressure diapnrnis, 3rd step of simultaneous welding or welding and cutting of thermoplastic sheets according to claim n I, characterized in that said thermoplastic sheets move in a uniform and uninterrupted movement while any number of bars, knives or wires heaters or heaters rectilinear or of any shape are arranged on a cylindrical surface and rotate around the axis of said surface so as to be applied by pressure on said stirrers with a relative speed practically zero by raort to said sheets, the contact between said bars, said knives or threads on the one hand and said sheets on the other hand being tangentially at one point or at several distinct points and (or) in a line or more lines located on a generatrix being perpendicular to the direction of movement of said sheets