DE2453321A1 - Forming elongate workpieces into annular articles - comprises pushing the heated ends of workpiece together - Google Patents

Abstract

A ring is made from a length of thermoplastic material by gripping its ends by clamps, pushing the ends onto a heating plate reciprocable to a position between the clamps, withdrawing the clamps, withdrawing the heating plate, and maring the clamps together to bond the heated ends together. The ring is provided with a ridge on its inner surface which ridge is engaged by a corresp. recess in each clamp, this sensing to align the ends of the length accurately.

Description

Ringfornunas chine The subject of this invention is a plant that ring-shaped workpieces made of long and thermoplastic materials Has to shape and manufacture objects. With this system or machine that provided with clamping devices for gripping and holding the ends of the workpiece is, but also with a heating plate, the two oppositely directed Has heating surfaces, the workpieces are attached to the heating plate by the clamping devices brought up and then connected to each other.

The shaping manufacturing of ring-shaped objects made of thermoplastic materials play an important role. at one of these cases is the manufacture of stroller tires solid elastomer plasticsw the market demands that these tires be very Must be manufactured inexpensively, with great importance nevertheless on the good appearance this stroller tire is placed.

The manufacture of such tires by injection molding is very expensive and also very much restricts the cross-sectional shape of the product to be manufactured strong one. The ones in the circumference or in the tread are important for the appearance incorporated grooves, and not only for the desired appearance of the tires, but rather also for the soft running properties of the tires, when used However, it is very difficult to produce such grooves using injection molding technology and shape.

It is believed that a process that will produce good results could be a combination that would is made up as follows: - from the injection molding of materials that do not have a circular cross-section; from cutting these materials into the appropriate lengths and from joining the ends of these materials to form a ring. The so far for this purpose developed and planned facilities were fraught with many problems. the Union of the two ends of a workpiece that is not circular in cross-section without good alignment of the ends with one another, i.e. without a match in shape, resulted in "scrap" that was unsightly and not perfectly round. In addition, the old methods of workpiece end fusing have become one Deformation and led to the formation of a "ridge". An important one for ring formation Another factor means that the shaping work can be carried out best when the workpiece is fresh from the injection molding machine. To be powerful To obtain a working machine must be a discontinuous process, like this one The process of tire manufacturing and tire molding is the case with a continuous ongoing process, for example injection molding, synchronized or synchronized be switched.

These and other difficulties and problems encountered so far known systems have emerged are within the scope of this invention to a perfect novel way avoided.

The aim of this invention is thus in the main to provide a Machine holding the two ends of a as a rod fed elongated Workpiece made of thermoplastic material to be connected to one another in this way is able to result in a ring.

Another object of this invention is to provide a machine which is designed in such a way that it is continuous supplied thermoplastic material is formed into ring-shaped tires.

Another object of this invention is to provide a machine which has to form rings or tires from rod-like materials in such a way that of you the ends of the materials are united, with exact alignment the non-circular cross-section of this supplied material.

Yet another object of this invention is to provide one Machine that works without burrs on workpieces made of thermoplastics is able to bring about a connection of the ends.

Another object of this invention is to provide a Machine for forming rings or hoops in which the finished ring or finished Tires can fall out of the processing zone without affecting parts of the machine having to affect.

Yet another object of this invention is to provide one Machine that v ,; the construction is so simple that the investment cost d the maintenance costs are low.

If these and other objectives of the invention are taken into account, then it should be clear to the professionals who work in that particular field because this invention is composed of a combination of parts that in the specification below and for those about the die-5 Patent application attached claims for patent protection is sought.

The subject of this invention is thus a plant or a machine for the production of ring-shaped objects made of thermoplastic materials. This system or machine includes two clamping devices that grab and hold the adjacent ends of the workpiece. Intended are also a heating plate for heating the workpiece ends as well as a device which brings the two softened workpiece ends together and these together connects. Around workpieces that do not have a circular cross-section, look good on one another To be able to align, a V-groove is worked into the workpiece, whereby accordingly shaped wedges assigned to the clamping devices in this V-groove on the workpiece intervene The melting together or fusing of the workpiece ends is achieved in that this is at the opposite ends or heating surfaces of the heating plate are held. These ends are from the heating plate removed again, even before the formation of a burr.

This invention will now be illustrated below with reference to the drawing Embodiment (of the embodiments shown in the drawing) closer explains t. The drawing shows in: -Fig. 1 A plant or machine of this invention in perspective view. This system or machine is used together with a It is reproduced truder.

Fig. 2 The function and mode of operation of important machine elements of this invention in general sketches.

Fig. 10 The system or machine in side view.

Fig. 11 The plant or machine in plan view.

Fig. In Eijie in the line XII-XII placed end view or front view FIG. 13 A front view laid in the line XIII-XIII, FIG. 14 Eiiie in the line XIV-XIV of Fig. 11 placedc side view.

Fig. 15 is a partially sectioned and shown in the line XV-XV of Fig. 11 laid view.

Fig. 16 A partially sectioned and shown in the line XVT-XVI of FIG. 15 laid view.

Fig. 18 A representation of the electrical circuit and the pneumatic Circuitry of the Plant of this Invention.

19 shows an illustration of a partially reproduced in cross section Tire 1 made according to the principle of this invention.

20 shows a plan relating to the wiring of the in the context of this r Invention used time-schaf tel'0 the detailed description of the construction and Operation of This Invention is a simplified description and illustration of the mode of operation, the representations of FIG. 2 to Fig. 9. Fig. 2 shows the start of the working process, i.e. the state in which a (left arranged clamping device 10 and a rec tits arranged Clamping device 10, each on the lines passing through points 12 and 13 are rotatably and pivotably mounted, part of a cylindrical and injection molded Grasp rod 14. Arranged over the extruded and cylindrical rod 14 are a cutting knife 15 and a heating plate 15. At this time, the cylinder-shaped Rod 14 held by the left clamping device 10 in a firm grip, whereas the cylindrical rod 14 held by the right clamping device 11 in this way as the rod 14 can slide in this clamping device 11.

As can be seen from Fig. 3, the left clamping device has 10 moved to the left and thereby also the end of the cylindrical rod 14 taken along.

Comes at a specific and predetermined position the leftward movement of the left clamping device 10 to a standstill the cylindrical rod 14 firmly clamped by the right clamping device 11, the cutting knife 15 moves downward to cut the rod L4 in such a way that that the workpiece 17 results.

Fig. 4 now shows that the cutting knife is retracted at the top has been that the clamping devices have continued to take care of theirs Pivot pins 12 and 13 'inwards, respectively.

According to Fig. 5, the clamping devices have an angle of Moved 180 °. The left clamping device 10 moves n; li right and the hot plate 16 will be hailed downwards.

As from Fig-. 6 shows, is the contact with the heating plate 16, which is now located between the two ends of Werkstjickes 17, made been.

Because of the flexible suspension of the heating plate 16, the through the Movement of the left clamp 10 transfers pressure evenly to each side the heating plate divided. Through the contact and temperature of the heating plate 16 the end faces of the workpiece 17 are correspondingly softened by melting.

Fig. 7 shows that just before the heating plate is moved out 16 from the space between the workpieces, the left clamping device 10 ends somewhat is moved back to the left, which has the consequence that the pressure from the softened Ends is removed, and the heating plate 16 without deforming the ends the end the space between the two workpiece ends can be moved out.

Fi (. 8 time the heating plate 16 out of the space between the two Workpiece ends have been moved out and the workpiece ends pressed firmly together so that a solid connection can be established between them.

The release of the workpiece 17, which is then removed from the system or from the machine can fall out, is shown with FIG. 9. Several opposite Directed movements bring the system back to its starting position.

Now a simplified representation of the function and the working method Given this invention, a machine will hereinafter be considered practical Embodiment of this invention will be described: -As from Fig. 1 showing the The essential features of this invention can best be seen to the ring forming machine marked with the general reference number 18 Extruder 19, a take-over device 20, a collecting device 21, a feed device 22, a processing device 23 and a control and regulation system 38.

The extruder 19 is a standard version for Manufacture of cylindrical rods 14 whose cross-section is equal to the cross-section of the tire 25 shown in FIG. 19. The main features of this Of the tires, it is expressly pointed out, are the grooves and projections 26 on the outer surface of the tire, but also the keyway 27 which is incorporated into the inner surface of the tire. The protrusions depressions 26 on the outer surface are important because they represent an important property which are difficult to achieve using conventional tire molding processes is. Keyway 27 on the inner surface of the tire is important as an aid to align the cross-sectional shapes with one another, as will be done in the following this patent application will be described later.

Fig. 12 reproduces the takeover device 20, namely on the extruder 19 aligned end of this transfer device 20. To this transfer device 20 include: the two wheels 28 and 29 and a guide that defines the passage 31 for the rod-shaped cylinder 14, i.e. the rod-shaped cylinder 14 must move through the space 31. The upper wheel 28 is an idle one Wheel, which is rotatably attached to the arms 33 with its shaft 32, which in turn in turn fost mounted on the base 34 sin (l. The guide 30 is via a connecting rod 35 attached to the arm 33. The lower wheel 29 sits on a shaft 36 which is in the holder 34 is rotatably mounted. Shaft 36 and wheel 29 are driven by a motor 37 and set in rotation.

The two arms or rods are assigned to the catching device 21 39 and a photocell 40.

10 and 11, the feed device 22 is in each case in the side view and shown in the top view. To this feed device 22 include: -the two wheels 41 and 42, a guide 43 as well a pneumatically operating displacement cylinder 44.

The upper wheel 41 is rotatable with its shaft 45 as an idle wheel Lever alarm 46 attached, which in turn on the bracket or the base 34 is attached. The guide 43 is attached to the lever arm 46 at the top. The lower Wheel 42, to which a lever arm 47 is attached, is rotatable in the holder or stored in the base. Between the outer end of the lever arm 47 and the bracket or base 34, a feed cylinder 44 is arranged in such a way that of it the lower Wheel 42 can be rotated forward and backward over an angle of 45 ° can.

The processing device 23 can be divided into four assemblies will. The cutting knife 15 and the pneumatic cylinder driving this cutting knife 15 48, but also the heating plate 16 and tfer driving the heating plate Pneumatic cylinders 49 are shown in FIG. 10. Fig. 10 shows the position of the left clamping device 10, the same also Fig.

11, the details being reproduced in FIGS. 14, 15, 16 and 17, respectively are. Shown in Fig. 10 is the position of the right clamping device 11, whose Details can be reproduced with FIG. 13.

As can be seen from FIG. 13, the cutting knife device is supported by a support arm 50 held. This cutting knife device includes: the cutting knife 15, the Cutting knife drive cylinder 48, the cutting knife guide 51 and the cutting support 52.

The right clamp assembly is also held by the support arm 50 from the right clamping device 11 with a fixed jaw 53 and one > movable jaw 54, with the right gripping cylinder 55, which closes the two clamping jaws caused, as well as a cylinder 56 for transmitting a rotary movement. The power transmission path between the right gripping cylinder 55 and the movable one Clamping jaw 54 corresponds to that for the left clamping device, which will be described in the following of this patent application will be described. From the rotary cylinder 56 is the right clamping device 11 via a rack 57 and a pinion to a Caused rotary movement, this rotary movement about the axis of the pinion 58 takes place.

It is important that the movable jaw 54 is directed towards them Has wedge 59 which engages in the keyway 27 of the cylindrical rod 14.

Are also attached to the support arm 30, as best shown in Fig. 10 can be seen, the feed cylinder 59, the splitting cylinder 60 and the Heating plate assembly. This heating plate assembly includes: -the heating plate or Welding plate 16, the welding plate drive cylinder, which the heating plate or Welding plate to proceed liat, as well as a fastening element that not only has to connect the heating plate 16 and the welding plate cylinder 49 to one another, but also the heating plate or welding plate 16 supplies the heat.

A thermal insulation is attached to the circumference of the fastening element 61 62 and an elastic stop device 63, which when they touch the earm 50 touched, the heating plate from the holding arm 50 and from the right Clamping device 11 pushes away.

As the last assembly of the processing device 23 is now the left Assembly shown and described. According to Fig. 11 belong to this left assembly: -die Slideways 64 and 65, the left clamping device 66, which are on the slideways is moved, as well as a feed cylinder 59, which the movement of the left clamping device 66 controls and regulates on the slide. This assembly also belongs to a distance cylinder 60, which controls and regulates the device 66 then takes over when it has been moved to the right-hand end on the slideways whereas a buffer cylinder or stop cylinder 67 is the movement of the device then monitors, controls and regulates when this is towards the left end of the slideways has been proceeded.

The left clamp assembly 66 itself is assembled from a (round plate 68, which moves or traverses on tien slideways 64 and 65 becomes, as well as a holding arm 69 which occurs rotatably via the bearing 70 can be pivoted is connected to the base plate 68. Type of the holding arm 69 attached are a stationCire Clamping jaw 71 and, via the pivot pin 73, also a movable clamping jaw 72. The left gripping cylinder acts along the axis of rotation of the holding arm, i.e. its bearing 70 74 on the gripping device via a hinge 75 in such a way that the clamping jaws be opened and closed. The hinge 75 creates with the jaws closed a state that at the end of the Clamping device only very reversible can be made. A similar drive system is also used for the right clamping device used. A rotary movement of the holding arm 69 comes about that the rack 76 on the pinion 77, which is attached to the holding arm 69, is moved. The order the base plate 68, the Halearmes 69 of the rack pinion 77 and the rack 76 is shown in FIG.

Fig. 14 also shows the rollers 78 that the rack 76 on the pinion 77 and the rotary cylinder 79, which drives the rack, hold.

The last system, the control and regulation system, is sketch force shown in FIG. This control and regulation system consists of one Combination of known construction elements, which are so arranged and each other are assigned that they have the devices and mechanisms previously described carry out the ring forming process already described above.

Using the description given so far, the use and the operation or function of this invention should be readily understood. In the The starting position or starting position shown in FIG. 1 is that in the injection molding process produced rod-shaped cylinder 14 from the wheels of the takeover device 20 pulled away from the extruder, the free end of the rod-shaped cylinder 14 is held by the feed device 22. The length in between can be in the Pick up device 21 sag until a sufficiently large part or sufficient great length saved has been and the photocell 40 responds, which in turn then closes switch P-1. It is assumed that both the feed cylinder 14 and the cutter cylinder 48 in the retracted Position. In this case, switches M-1 and M-6 are closed, what in turn results in the solenoid or magnetic drive S-3 causing the feed cylinder 44 moves to the right.

By this movement, the switch M-1 is opened, whereas switches M-2 and R-1 are closed. Closing R-1 will do that Approach of the feed cylinder 44 continued, in addition, it comes from the Closing the switch R-1 to approach the plunger of the buffer cylinder 67 and the spacer cylinder 60 using the solenoid or magnetic drive S-8. By working these cylinders, switch M-4 is closed, which in turn the result is that the relay R2 is energized, that the switch R-2 is closed. If switch M-3 closes, this indicates that that the feed cylinder 44 has extended its full stroke length continues to begin in this case then the feed cylinder 59 to work. In this case, be on it it should be noted that by operating the feed cylinder 44, the material, i. the rod-shaped cylinder 14 from the injection molding process, into the processing device 23 is introduced. The processing device is located at the beginning of a work cycle in the sketchy position shown in FIG. Both the cutting knife 15th as also the heating plate or welding plate 16 are located in their respective upper stream Sibilung, whereby the left clamping device 10 is pushed to the right, and zwarkderart, that both retaining clamps or jaws of ifrer Drehachsulaus are directed upwards are. The rod-shaped and extruded cylinder 14 is guided under the cutting knife, through the right clamping device 11 and under the heating plate 16 by the left clamping device 10.

When the feed movement begins, the solenoid becomes activated at the same time or magnetic drive S-2 controlled and put into operation in such a way that the left clamping device 10 using the left gripping cylinder 74 around the End of the extruded cylinder rod 14 closes. Albeit through the push movement the left clamping device 10 is moved to the left, it will in the end the end of the extruded cylinder rod 14 pulled through the machining device, until the left base of the clamping device, i.e. the base 66, the feed buffer cylinder 67 contacts. Is the buffer cylinder 67 that runs along the slideways 64 and 65 can be adjusted, then fully retracted the switch M-5 is closed. As a result, the solenoid S-5 the right gripping cylinder 55 for this purpose, the right clamping device 11 all around to close the extruded cylinder rod 14, but also to close it at the same time of the switch M-9 to bring about the knife movement via the solenoid S-6 and to initiate the knife cylinder 48.

The M-6 switch is opened by the cutting process, on the contrary the switch M-7 is closed.

Opening the switch M-6 has the consequence that the feed mecliai-ii.s'mus returns to the starting position, so that the feed buffer mechanism also continues and the spacer mechanism is brought to the home position via switch R-1 will. By closing switch M-7, relay R3 and the relay contacts R-3 switches the feed movement in the opposite direction In addition, the rotary movement of the clamping devices is also initiated. This turning movement is actuated through solenoid S-7 and cylinders 56 and 79.

After completing the turning movement, switch M-8 will close in addition, lowering the heating plate or the welding plate 16 over the welding plate cylinder 49 initiated. This lowering of the heating plate or welding plate takes place sylichronically with the rightward feed movement of the left clamping device 10, as can be seen from FIG.

Finally, the feed movement of the left clamping device leads 10 and the lowering of the heating plate or welding plate 16, both ends of the Workpiece come into contact with the heating plate or welding plate.

The contact time during which the two ends of the workpiece die Touching the heating plate or welding plate 16 is done in the usual way by time switches controlled and regulated, the end of the contact time by a pulsed extension of the spacer cylinder 60 is brought about by overriding the to the right directed movement of the left clamping device lower part 68 a temporary caused movement to the left. During the time in which the work pieces end Detach from the heating plate or welding plate, this becomes a heating plate or welding plate removed from the haunch between the ends of the workpiece and moved upwards. this has the consequence that when the pulse-like effect of the spacer cylinder - <- lers stops by resuming the rightward feed movement melted and deeply softened ends of the workpiece 17 in contact with one another to be brought. In this context it should be pointed out that d <'r for the welding process specific timer is designed and set in such a way, that then, when the contact time with the heating plate has expired, the contact W-l is opened, whereas deT 'Kont; ict W-3 just before the contact opens W-3 is closed. Due to the specified time delays, this follows through the opening of the contact W-1 caused the heating plate or the welding plate to start up briefly the initiation of the removal of the plate pressure by the closing process at contact W-2. The subsequent opening of contact W-3 removes the touch stopped, i.e. the movement sequence of the clamping device 10 directed to the left.

This has the effect that before the heating plate is started up the pressure of the workpiece ends on the Heating plate or on the welding plate is taken away. In this construction, the elastic stop 63 helps the heating plate pushes away from the workpiece and assigned to the right clamping device 11 But this means that there is contact between the ends of the workpiece and the heating plate is only given if from the workpiece end that to the left clamping device 10 heard, pressure is transferred to the heating plate or to the welding plate.

By resuming the rightward movement of the The left clamping device will have both melted and therefore soft ends of the workpiece brought into contact with one another. After the end of the workpiece end welding process give the clamping devices, i.e. the left clamping device and the right clamping device, the finished tire is easily released, which then falls unhindered into a container can. Based on the description, the return of the machine elements should be in their Starting positions be clear.

It should be understood that without departing from the spirit of this invention to have to make minor changes to the shape and construction of the embodiment of this invention can be made. It is for this reason that this invention is intended not only be limited to the exemplary embodiment described, but rather include everything within the scope of the claims attached to this patent application falls.

Claims (9)

Patent claims: - 1. Plant for the production of ring-shaped counterparts from rod-shaped thermoplastic workpieces with a first end and a second end. This system consists of a machine te; a first clamping device, which is mounted on this machine plate in such a way that it can be moved - This first clamping device for gripping and holding the to the workpiece belonging first end; a second and also movable on the machine attached clamping device for gripping and holding the second workpiece end; There is also a heating plate or welding plate with oppositely directed Surfaces, a first and a second surface that are mutually parallel are arranged. This plant d a d u r c h e k e n n n z e i c h n e that to it a takeover and positioning device is part of the first end of the Workpiece has to be fed to a first surface on the Ma nenplatte; that eventually a manipulator is also provided, which extends the second end of the workpiece bring the second clamp to a second surface of the machine platen Has. 2. Plant according to claim 1, characterized in that a cutting knife is present that the elongated workpiece from an emerging from the extruder and cut off the extruded elongated strand. 3. Plant according to claim 2, characterized in that between the Cutting knife and the extruder a take-over zone and a storage zone respectively is available; that finally always a display or a control process is carried out when there is a sufficiently large length of the extruded in this zone Rod cylinder has accumulated. 4. Plant according to claim 1, characterized in that the elongated or bar-shaped workpiece has a concave groove extending in the longitudinal direction having; that finally each of the clamping devices with a projection is corresponding Form is provided, which then engages in the groove when the workpiece from the clamping devices is being held. 5. Plant according to claim 1, characterized in that the first Clamping device can rotate about a first pivot point, which in view of the Base plate is fixed; that the second clamping device is a second Can rotate the pivot point, which is fixed with respect to the machine plate, 6th Installation according to Claim 5, in which the positioning device is indicated and the manipulator each have their associated clamping devices on the trunnions move by 180 ° from a first position to a second position rotating if the workpiece is held by the clamping devices; that the ends of the workpiece moved away from each other in the first position, but in the second position towards each other. 7. Plant according to claim Ci, characterized in that to the aforementioned Manipulator includes a first drive and a second drive, the second Drive can override the first drive from time to time; that these drives can be used to adjust the spacing between the second pivot pin and to change the bracket. 8. Aniage according to claim 1, d a d u r c h g e k'.e n n z e i c h n e that an elastic buffering device is present w the one given Maintain the distance between the heating plate and the first end at all times, except then when the second end is in touch with the heating plate. 9. Plant according to claim 1, characterized in that the plate can be placed in a position between the workpiece ends; that a touch contact between the plate and the workpiece ends; that the plate is not out of position removed when either end is in touch with it. - End -