DE1924061A1 - Local friction welding of overlapping plas- - tics sheets, for hooping packagings - Google Patents

Abstract

Tensioner is on a body which carries the band regions to be joined between friction clamps. At least one clamp is movable in a rapid reciprocation, to take up the strip section lying on it and maintain a pressure. The reciprocation is perp. to the length of the overlapping strips. Pref., the reciprocating clamp is mounted on a stamp which can move towards the other clamp.

Description

Device for area-wise welding of partially overlapping ends Tapes of thermoplastic material by means of frictional heat The invention relates to a device for area-wise welding of partially overlapping ends Tapes made of thermoplastic material by means of frictional heat, especially in the Strapping of packages, with a base body having a tensioning device, which carries the band areas to be connected between the friction jaws, wherein at least one friction jaw with entrainment of the band section lying against it a rapid back and forth movement when maintaining contact pressure is relocatable. In these known devices, the reciprocating movement takes place the friction jaw and the belt section resting against it in the longitudinal direction of the belt. By this back and forth movement of the belt section in contact with the friction jaw The longitudinal direction of the belt is that between the tensioning device and the friction jaw extending band area steered, whereby a permanent deformation in the band cross-section and thus a reduction in belt strength occurs.

The invention is based on the object of providing a device of the initially described to create explained type in which such disadvantages are avoided. This goal is essentially achieved according to the invention in that the to-and-fro movement takes place transversely to the longitudinal extent of the overlapping tape areas. This will achieved that in the back and forth movement transversely to the longitudinal extension of the over overlapping band areas, only very slight changes in length occur, as a rule lie within the elastic deformation of the band. A permanent cross-sectional deformation length of the tape is avoided.

One is advantageous transversely to the overlapping band area running to and fro movement performing friction jaw slidably on an in Mounted in the direction of the opposing jaw displaceable punch. This achieves that only a few parts have to perform the reciprocating movement while the required The friction jaw is pressed in the direction of the counter jaw by means of a stamp.

The displaceable friction jaw advantageously has an extension with a recess into which an arm of a pivotably mounted on the base body two-armed lever engages, the other arm in a fork-shaped end a Eccentric part of a drive axis running parallel to the longitudinal direction of the belt recorded. This ensures that the rotary movement of the drive axle is easier Way over the eccentric part and the two-armed lever in a reciprocating manner Movement of the friction shoe is reshaped, The lengths of the reciprocating movements can thereby in a simple manner by the eccentricity of the eccentric part and the Leverage ratio of the two-armed lever can be varied.

The fork-shaped end of the lever arm is expediently covered a bush which is placed on the eccentric part of the drive axle with a needle bearing is. As a result, the friction between the fork-shaped end is reduced in a simple manner of the two-armed lever and the eccentric part, the the slidable friction jaw in the direction of the opposing jaw pressing the punch the action of a spring-loaded lever that strives to the stamp and thus to transfer the friction jaw into the pressing position 0 This ensures that the Stamp and thus the friction jaw is held in a force-locking manner in its pressing position.

The pressure lever pivotably mounted on the base body has an advantageous effect with a short lever arm on a rear extension of the punch, while the other lever arm is longer and has a recess for partial engagement has a helical compression spring, which is at its other end in a supports a cover plate provided for the punch guide recess. Through this it is achieved that with a spring whose spring force is relatively weak, a large contact pressure of the friction shoe is achieved.

Advantageously, the lever acting on the stamp is located a pawl pivotally mounted, which is in the release position of the stamp against creates a shoulder formed by a projection. This ensures that the Andrllckhebel and thus the punch and the friction jaw in their release position is lockable. In this position, the bands between the friction jaw and the counter jaw can be inserted.

The friction jaw is expediently affected one relatively weak spring that strives to oppose the friction jaw and thus the punch to hold the lockable pressure lever. This ensures that this spring presses the friction jaw and the punch against the fixed pressure lever, so that the bands can be inserted between the friction jaw and the opposing jaw.

The pawl mounted on the pressure lever is useful with a a lever provided nose can be lifted. This allows the pawl in a simple manner be excavated so that the pressure lever the punch and the friction jaw in their Active position transferred.

The drive shaft driving the friction jaw advantageously drives at the same time A tensioning wheel of the tensioning device is attached via a worm and a worm wheel. Through this it is achieved that the torque acting on the drive axle at the same time drives the tensioning wheel of the tensioning device to tension the strapping.

According to a further proposal of the invention, the clamping device when a predeterminable tape tension is reached, the drive axle automatically releases itself uncouple and move the pawl mounted on the pressure lever to the release position. This ensures that when a predeterminable belt tension is reached, a further tensioning of the strapping is set and the friction jaw is in its operative position is transferred, whereby the Sohweissvorgang is initiated.

When the predetermined belt tension is reached, a with the drive axis of the friction jaw coupled, the screw having the axis part move in the longitudinal direction, and thus move away from the drive axis of the friction shoe uncouple and actuate the lever that lifts the pawl with the nose, thereby. becomes easier in Way for disengaging the clamping device and bringing the Friction jaw a longitudinal displacement of the anyway having an axial component Worm gear used.

The shaft part having the screw advantageously has on its one end is a coupling part with a plurality of radially outwardly projecting projections on, which rest in the coupled position against the coupling pin and in the uncoupled position in recesses of the coupling pin arranged without overdrive are. This ensures that the worm in the coupled position having axle part are rotatably connected to the drive axle, while in the decoupled position the further rotating drive axle with the coupling pin the outwardly protruding projections of the coupling part in recesses without contact records.

Advantageously, the coupling pins are from the free ends of planetary gear axles of a planetary gear provided on the drive axle of the friction jaw educated. As a result, the coupling pins are already present in a simple manner Planetary gear shafts used, with the planetary gear transmission at the same time being a large one Reduction is achieved.

The aohgea part which has the screw expediently has a circumferential annular groove in which the lever actuating the latch with a nose engages with a cam provided on its axis. This will make it easier Way achieved that duroh the displacement of the screw exhibiting Axis part at the same time the pawl is released so that the friction jaw is in their active position is convicted.

It is useful to have one for the screw on the axis part the worm wheel slotted bushing a @ fgesch @ ben, which is at one end against the thrust bearing of the axle part and the other end against the cam of the pawl release lever. It is thereby achieved that the pivoting of the axis having the cam over the bushing takes place, which is supported against the thrust bearing, which is required anyway.

A spring advantageously acts on the pawl against the direction of extraction a, which is loaded itt an adjustable preload force. This achieves that the pawl automatically returns to its operative position and with the adjustable Pretensioning force the increased belt tension is adjustable.

The pretensioning spring is advantageously a very helical compression spring formed and arranged inside the hollow Klinke kenausrückhebels, wherein one spring end on one provided on the pawl into the hollow pawl release lever protruding Ar acts. This makes the spring in a simple manner in any case existing ratchet release lever arranged, so that further means for the holder the spring are dispensable.

A threaded pin acts on the other end of the spring in an expedient manner one that is drawn into a threaded hole in the free face of the ratchet release lever and with is locked with a screw button. This makes it easy Way, the preload of the helical compression spring adjustable, the preload adjusting threaded pin cannot unintentionally loosen.

The one that interacts with the nose of the ratchet release lever is useful Part of the pawl by a pivoting part held in its operative position by a spring educated. It is thereby achieved that the latch release lever having the nose can be transferred into its operative position, even if the pawl is already in its Locked position.

The tensioning device is advantageously a spring-loaded release lever assigned, itt the one hand the counter jaw for the tensioning wheel in a release position and on the other hand the pressure lever for the stamp can be moved into the fixed position is. It is thereby achieved in a simple manner that after the welding of the band areas by actuating the release lever, the tape from the tensioning device and from the Welding device is removable.

Advantageously, the release lever acts with a laterally held one Roll sit together on an inclined surface of the pressure lever. It is thereby achieved that when the release lever is actuated, the spring-loaded Andrdekhebel in its The release position is transferred and the latch is held in this position can.

Conveniently, the drive axle for the friction jaw is from driven by a motor, preferably a high-speed air motor. Through this is achieved that a particularly fast back and forth movement the friction shoe is achieved, so that the temperature required for welding is very high will soon be achieved.

A knife can expediently be attached to the friction jaw, which can be moved back and forth be held to cut the tape. In this way, the backward and forward movement of the friction shoe used to cut the tape.

The invention is shown in an exemplary embodiment in the drawing namely show: FIG. 1 the device according to the invention in side view, partially broken off, FIG. 2 shows a detail of FIG. 1, partially in section, FIG. 3 shows that in FIG Fig. 2 shows detail of the device in a different position, Fig. 4 a Section along the line IVTIV of FIG. 1, FIG. 5 a section along the line V-V 1, partially broken away, FIG. 6 shows a section along the line VI-VI of Fig. 5, Fig. 7 a section along the line Vil-VIl of Fig. 1 and Fig. 8 is an end view of the supplementary part.

The device shown in the drawings is powered by an air motor lo driven. The axis of rotation ii of the compressed air motor lo runs parallel to the band, not shown in detail, to be connected to the device.

The compressed air motor io is on the base body via a gear part 12 13 flanged to the device. The base body 13 has a counter jaw 14 for a friction jaw 15, between which the partially overlapping bands for can be arranged by welding. The counter jaw 14 is below the partially overlapping bands, while the friction jaw 15 is arranged over it is.

As can be seen in particular from FIG. 4, the friction jaw 15 is slidable transversely to the longitudinal direction of the belts.

For this purpose, the friction jaw 15 is provided with an extension 16 which has a recess 17. An arm 18 engages in this recess 17 on the base body 13 pivotally mounted two-armed lever 19, the other arm 21 with a fork-shaped end 22 an eccentric part 20 which is parallel to the longitudinal direction of the belt extending drive axle 11 detected. The eccentric part 2e of the drive axle is left while being provided with a bush 24 mounted on a needle bearing 23 so that the Friction is relatively small.

About the eccentric 20 and the two-armed lever 19 is thus the Friction jaw 15 when rotating the drive shaft il a reciprocating movement imposed.

The friction jaw 15 lies against with the interposition of rollers 25 the underside of a stamp 26 on. The friction jaw 15 will be there held in contact with a spring 27 inserted in the underside of the base body, wherein the spring at the same time the friction jaw 15 and the punch 26 in the release position convicted.

The punch 26 has a rear extension 28 in a vertical guide 29 is supported vertically displaceable. The one open to the front Guide 29 of the punch extension 28 is closed by a cover plate 3o. A pressure lever 31 acts on the free end of the punch extension 28, The Pressure lever 3i is supported pivotably about the screw pin 32 and has a short arm 33, which when the pressure lever 31 is pivoted into the position shown in FIG. 3 active position shown the Stem pel 26 and thus the friction jaw 15 in the active position convicted. The pressure lever 31 has a slightly longer arm 34 in which a Recess 35 for a helical compression spring 36 is present. This helical compression spring 36 is supported with its other end in a recess 37 in the cover plate 30 away. The pressure lever 31 thus endeavors to achieve its in Fig. 3 shown active position öinzunebien.

The pressure lever 31 has a third arm 38 on which a bearing pin 39 is provided. On this bearing pin 31, as shown in particular in FIG. 1 er-siobtlioh, a pawl 40 pivotally mounted. The pawl 4o works in the release position according to FIG. 2 with a shoulder 42 formed by a projection 41 together, the guide on the punch 29 and the cover plate 30 are provided is. The pressure lever 31 and thus the punch 26 and the friction jaw 15 is thus in the Release position can be locked.

The pawl 40 is connected to a pawl release lever 43 via a nose 44 can be lifted out. As can be seen in particular from FIG. 1, can thus with a Pivoting the pawl release lever 43 in the counterclockwise direction Pawl 40 lifted. The nose 44 engaging under the pawl 40 is of one Stamped part formed, which can be adjusted with two screws 45 to 46 on the latch> release lever 43 is held.

As already mentioned, the compressed air motor 10 is a transmission part 12 downstream. This gear part 12 is designed as a planetary gear. The planetary gear axles 47 also serve as coupling pins for a coupling part 48, which is provided on a downstream axle part 49. The coupling part 48 is, as can be seen in particular from FIG. 8, with six radially outwardly protruding projections so provided that in the engaged position against the coupling pins formed by the planetary gear axle are in contact. Removed from the free ends, the coupling pins 47 are provided with recesses 51 in which the radially outwardly projecting projections So of the coupling part 48 in the uncoupled Position are arranged without contact. In the uncoupled position can thus rotate the planetary gear axles 47 around the coupling part 48 without taking it along. The coupling part 48 and the axle part 49 are therefore required to disengage the clutch longitudinal to move. This is done on the rotatable Axle part 49, the worm 52 of a worm gear is placed in such a way that during operation of the transmission on the axis part 49 having the worm 52 Component in the alignment of the coupling 47,48 acts.

The worm 52 of the worm gear mechanism acts on the worm gear 51 a, on the axis 54 of which a tensioning wheel 55 of a tensioning device 56 is held in a rotationally fixed manner is. The clamping device 56 is used to clamp a package or the like. laid Umrelfungsbandes. The tensioning wheel 55 is pivotable about a screw pin 57 assigned counter-jaw 58, which holds the lower end of the tape.

The pivotably mounted counter jaw 58 is under the action a leg spring, not shown, arranged around the screw pin 57, whose legs are supported against the pins 59 and 6e. The pivoted te counter-jaw 58 is thus held positively in its operative position. At the The pivotably mounted counter jaw 58 is a pivotably mounted band holder 61 stored, with a nose 62 protruding downward in the operative position, the tape holds sideways. The tape holder 61 is provided with an upwardly protruding pin, which protrudes into a recess 64. This causes the tape holder 61 to be transferred the counter-jaw 58 in its release position is also transferred to its release position.

On the pivotable counter jaw 58 is an angled release lever 65 attached. By actuating this release lever 65, the counter jaw 58 is the Clamping device 56 can be moved into its release position. On the release lever 65 is a laterally mounted roller 66 is provided with an inclined surface 67 a @ arm 38 of the pressure lever 31 cooperates. When the release lever 65 the pressure lever 31 is thus transferred into its release position.

When the release lever 65 is actuated, not only the Counter jaw 58 of the clamping device 56 but also the friction jaw 15 in their release positions transferred so that the device is removable from the belt. When you press the Release lever 65 is at the same time another tape holder 68 in its release position transferred, which comes into operative connection with the lower edge of the release lever 65. The tape holder 68 is on the endo of the device facing the friction jaw 15 mounted displaceably in the vertical direction on a Sohraubzapfen 69, which in a horizontally extending arm 70 has a recess 71 for the band.

The screw pin 69 engages through it. an elongated hole 72, the one has lateral recess 73 for a spring 74. The spring 74 strives to to hold the tape holder in the operative position.

As already mentioned, the clamping device is disengaged 56 driving axle part 49 by a longitudinal displacement of the screw 52 having axle part 49.

The axis part 49 having the screw 52 is thereby of a Spring force held in the coupled position, @o that the shift and thus the uncoupling of the axle part 49 only after the adjustable spring force has been exceeded he follows. The axis part 49 having the screw 52 has a circumferential one for this purpose Annular groove 75 in which the pawl 40 with a nose 44 actuating the pawl release lever 43 engages with a cam 77 provided on its axis 76.

The axis part 49 having the screw 52 is united for the worm wheel 53 slotted bush 78 pushed on, which is at one end against the axial bearing 79 of the axle part 49 and at the other end against the cam 77 of the ratchet release lever 43 supports. This causes the displacement of the axle part 49 and the axial bearing 79 transferred directly to the cam 77 of the ratchet release lever 43.

When the part of the axis having the worm 52 is displaced 49 is thus at the same time the axis 76 of the ratchet release lever via the cam 77 43 pivoted, in the sense of lifting the pawl 40. The pawl 40 is stationary however, under the action of a helical compression spring 80, which is inside the hollow Ratchet release lever 43 is arranged. The helical compression spring 80 is supported here with one of its ends against one provided on the pawl 40, into the hollow pawl release lever 43 protruding arm 81 from. A threaded pin 82 acts on the other end of the spring one that goes into a threaded hole 83 in the free face of the ratchet release lever is retracted and locked with a screw button 84. With this helical compression spring 80, the bias of which is adjustable, the pawl 40 is thus in its locking position held. Only after the pawl has been exceeded in its locked position Pivoting of the pawl release lever 43 is possible by force. With the adjustable ' Pre-tensioning force of the helical compression spring So the tensioning force of the tensioning device 56 can be set, because with the spring force of the helical compression spring, so does that the screw 52 having the axis part 49 is held in the operative position. at an exceeding of the adjustable clamping force of the clamping device 46 moves the shaft part 49 having the worm 52 thus couples the drive the clamping device and lifts the pawl 4o so that the friction jaw 15 in it Active position is transferred. When you broke the desired belt tension thus becomes there. Tensioning of the belt set and nit the friction jaw 15 on the overhead Tape end a reciprocating motion is imposed, so that the thermoplastic Existing plastic straps are rubbed against each other, developing heat in the process, which is sufficient to soften at least the surfaces of the tapes that are on top of one another and weld them together.

A knife 85 is held on the friction jaw 15, which can be moved to and fro, that during the back and forth movement of the friction jaw 15 at the same time on the overhead End of tape acts and rubs through.

As already mentioned, the embodiment shown is only an example Realization of the invention and this is not limited to it. Rather are still various other designs and modifications possible.

Claims (24)

Expectations: 1. Device for partial welding of itself in areas overlapping tapes of thermoplastic material by means of frictional heat, in particular when strapping packages, with a clamping device having Base body, the friction jaws that hold the band areas to be connected between them carries, with at least one friction jaw taking along the band section lying against it in a rapid to-and-fro movement while maintaining a pressure druoke is displaceable, characterized in that the back and forth movement is transverse to the longitudinal extension of the overlapping tape areas. 2. Apparatus according to claim 1, characterized in that the one performing a reciprocating movement transversely to the overlapping belt area Friction jaw displaceable on a punch displaceable in the direction of the counter jaw is stored. 3. Apparatus according to claim l or 2, characterized in that the sliding friction shoe has an extension with a recess, in which engages one arm of a two-armed lever pivotably mounted on the base body, the other arm with a fork-shaped end an eccentric part of a parallel to the longitudinal direction of the belt running drive axis detected. 4. Apparatus according to claim 3, characterized in that the fork-shaped The end of the lever arm grasps a socket, those with a needle bearing is placed on the eccentric part of the drive axle. 5. Device according to one or more of claims 1 to 4, characterized characterized in that the sliding friction jaw in the direction of the opposing jaw pressing stamp is under the action of a spring-loaded lever that strives is to transfer the punch and thus the friction jaw into the pressing position. 6. Apparatus according to claim 5, characterized in that the am Base body pivotably mounted pressure lever with a short lever arm on one rear extension of the punch acts, while the other lever arm is longer is dimensioned and a recess for the partial engagement of a helical compression spring has, the other end in a in a cover plate for the Supports punch guide provided recess. 7. Device according to one or more of claims 1 to 6, characterized characterized in that a pawl is pivotable on the lever acting on the punch is stored, which is in the release position of the stamp against one of a Protrusion formed shoulder. 8. Device according to one or more of claims 1 to 7, characterized characterized in that the friction shoe is under the action of a relatively weak spring stands, which strives to the friction jaw and thus the punch against the fixable To hold the pressure gable. 9. Device according to one or more of claims 1 to 8, characterized characterized in that the latch mounted on the Andrüokhebel with one on a lever provided nose can be lifted. 10. Device according to one or more of claims 1 to 10, characterized characterized in that the drive shaft driving the friction shoe also has a Worm and a worm wheel drives a tensioning wheel of the tensioning device. 11. Device in particular according to one or more of the claims 1 to 10, characterized in that the clamping device when reaching a Predeterminable belt tension is automatically released from the drive axle the latch on the pressure lever moves into the release position. 12. Device according to claim 11, characterized in that when the predetermined belt tension is reached an axis part which is coupled to the drive axis of the friction jaw and has the worm shifts in the longitudinal direction, thereby moving away from the drive axis of the friction jaw uncoupled and actuated the lever that lifts the pawl with the nose. 13. The apparatus according to claim 12, characterized in that the the screw having the axis part at one end of a coupling part with several has radially outwardly projecting projections in the coupled position rest against the coupling pin and in the uncoupled position in recesses the coupling pins are arranged without contact. 14. The device according to claim 13, characterized in that the Coupling pin from the free ends of planetary gear axles one on the drive axle the friction shoe provided planetary gear are formed. 15. Device according to one or more of claims 11 to 14, characterized in that 'the one having the screw Axle part has a circumferential annular groove in which the one actuating the pawl with a nose Lever engages with a cam provided on its axis. 16. Device according to one or more of claims 11 to 15, characterized in that on the axis part having the screw one for the worm wheel slotted bushing is pushed on, which is at one end against the Axial bearing of the axle part and at the other end against the cam of the ratchet release lever supports. 17. Device according to one or more of claims ll to 16, characterized in that the pawl is also a spring counter to the direction of extraction acts, which is loaded with adjustable preload force. 18. The device according to claim 17, characterized in that the Pre-tensioning spring designed as a helical compression spring and inside the hollow ratchet release lever is arranged, wherein the one spring end on a provided on the pawl, in the hollow ratchet release lever protruding arm acts. 19. Apparatus according to claim 17 or 18, characterized in that that a threaded pin acts on the other end of the spring, which is inserted into a threaded hole pulled into the free face of the ratchet release lever and with a screw button is segregated. 20. Device according to one or more of claims 1 to 19, characterized characterized in that the cooperating with the nose of the ratchet release lever Part of the pawl by a pivoting part held in its operative position by a spring is formed. 21. Device according to one or more of claims 1 to 20, characterized characterized in that the clamping device is assigned a spring-loaded release lever is, with the one hand the counter jaw for the tensioning wheel in a release position and on the other hand the pressure lever for the stamp can be moved into the fixed position is. 22. The device according to claim 21, characterized in that the Release lever with a laterally mounted roller with an inclined surface of the pressure lever cooperates. 23. The device according to one or more of claims l to 22, characterized characterized in that the drive axle for the friction shoe is from a motor, preferably is driven by a fast running booklet motor. 24. Device according to one or more of claims 1 to 23, characterized characterized in that on the back and forth friction jaw a knife for cutting off of the tape is held. L e r s e i t e