DE1238194B - Device for slitting plastic pipes, in particular for drainage purposes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

B29d

German KL: 39 a3- 23/00

Number: 1238194

File number: F 45432 X / 39 a3

Filing date: March 6, 1965

Opened on: April 6, 1967

It is known to cut plastic pipes with rotating circular saws or milling cutters that periodically be moved back and forth to the pipe. The slits created in the process have one inside the pipe unavoidable burr. Experience shows that this gives, for example, when used as a drainage pipe Reason for so-called ochering, which over time leads to complete closure of the Slots and thus leads to the pipe becoming unusable.

It is also known to perform the perforation of the pipe from the inside of the pipe by in the Flow path of the still soft plastic material flow obstacles inserted and removed again will. A corresponding elongated hole is therefore cut out at the points of these obstacles. at a known device of this type radial plungers are arranged in the inner mandrel, which against Spring pressure can be pressed outwards into the flow path of the material by cams. The cams are located at the front end of the screw of a standard plastic screw press. This execution has several disadvantages. One disadvantage is that you have to adjust the diameter of the pipe below is too limited because the tappets and the camshaft, but especially the coil springs for the Plunger return take up considerable space in the direction of the diameter of the pipe. Another The disadvantage is that the distance between the recesses in the longitudinal direction of the tube is rigidly dependent on the speed of the Press screw is bound, so it cannot be chosen according to other circumstances or freely. Finally, the known device is quite expensive. In particular if a plurality of If slitting devices are to be provided for different pipe diameters, this is very disadvantageous.

The invention relates in the narrower sense to a slot device in which the slots also are generated from the inside of the pipe by flow obstacles that can be switched on and off.

It is the object of the invention, through the formation of the flow obstacles and their control elements, to create a system that is much simpler and easier to manufacture Specify slitting device in which there is no coupling of the slitting sequence with the screw speed is present, which accordingly does not require the use of an upstream plastic press is bound with a screw and also with pipes of a comparatively very small inner diameter is usable.

The new device for slitting art device for slitting plastic pipes, especially for drainage purposes

Applicant:

Frieseke & Hoepfner G. m. B. H.,

Erlangen-Bruck, Tennenloher Str. 41

Named as inventor:

Ludwig Müller,

Heinz Bisping, Erlangen

fabric pipes, in particular for drainage purposes, in the the tube is guided in an annular gap between a calibration tube and an inner mandrel and at which can be switched on and off from the inside of the pipe Flow obstacles for the still soft plastic material are generated and the Flow obstacles arranged in the inner mandrel, movable outwards, the material flow in places are interrupting bodies, which are in Connection with sliding surfaces provided on the bodies in and out of engagement with the material are brought, characterized in that the flow obstacles are attached tangentially in the inner mandrel Bolt mounted as well as extending in the flow direction of the plastic and outwards are pivotable cutting blades and that the control cam for pivoting the cutting blade in and out is axially displaceable. It should be noted that the control body also perform periodic rotary movements can, if the control cam runs approximately spirally on the control body. But this is again more complex. In any case, it is only important that the part in engagement with the knife is Control cam on the knife moved back and forth in the axial direction.

The control cams can be turned relatively easily on the control body. Return springs for the swiveled-out cutting knives are unnecessary, since both the swiveling out and the return the knife inevitably caused in a simple manner by appropriate design of the control cams will.

In one embodiment of the invention, the calibration tube has opposite the cutting knives Indentations. The cutting knives in the

709 548/377

Claims (1)

3 4 extended state. This makes a mandrel displaceable lengthways. To the sliding drive particularly clean working of the device achieved. is used for pneumatic or hydraulic working In a further embodiment of the invention, cylinder 18 is used. This will not be discussed in more detail, the inside of the tube at the points where, because it does not belong to the invention,
The slitting is to be made later, with 5 At the rear end, the inner mandrel has a longitudinal groove. This can have different connection pieces 19 for the supply of cooling profile. In this way it can be achieved that the liquid. This flows, as indicated by the arrows drawn in from the inner wall of the pipe into the slot, rounded on the outside of the pipe 15 and thus effectively prevents ocher formation for a particularly long time to the space 20 of the inner mandrel. The longitudinal groove can easily be made in the opening 21 and the inside of the pipe back for play-out in that the inner let-out 22. thorn in front of the cutting knives cams or the like has, the brierungsrohr 4 with the cutting blades has a recess 23. Furthermore, the cursing. The pipe sliding past then already has an inner mandrel close to the entry of the plastic mass in the mentioned groove if there is a cam, a nose, in the place of the cutting 15 the calibration annulus knife comes. 24 or the like. In a further embodiment of the invention, the FIG. 1 shows the cutting knife 13 in one Control body, which carries the control cams, from a middle position. Here are each of his two Tube are moved, the lugs 11 and 12 on the edge of one of the control cams 9 in a manner known per se for supplying or draining cooling liquid 20 and 10 respectively. If now the pipe 15 and thus the serves for the inner mandrel. As a drive for the tubular control body 8 by the working cylinder 18 according to If a pneumatic or hydraulic movement is pulled at the rear, the cutting knife 13 positions itself Working cylinder according to FIG. 3 because of its small dimensions. Through the bridge between and simplicity in construction are advantageous. Because of the curves 9 and 10, the nose 12 is up Pistons inherently straight movements 25 and thus the upper one that forms the flow obstacle executes, a gear mechanism is unnecessary, such as the rear corner of the knife in the recess 23 it presses for example when using electric. The mass flow is interrupted by gates would be required. The use of one of these so that, in the end, the desired deepening like working cylinder offers the possibility, which is located in the exiting pipe. The nose 11 of the measuring Retraction and extension of the knife relatively suddenly 30 sers 13 slides during the pivoting movement on the to be done. Then the front and sole of the control cam 9 are also. Rear edges of the slots are not as sharp as. In an analogous manner, when the in the known embodiment, the nose 11 of the knife is raised by the control body 8 in the ram. Cam and thus more continuously in the Ma- The nose 12 now slides on the bottom of the curve material current are brought. 35 10 and the cutting edge of the knife 13 disappears The control of the periodic movements of the completely inside mandrel. It is obvious that both The tube for the control body is expediently inevitable in the swiveling out and in of the knife is effected in a known manner from the exiting plastic pipe by the drive of the control body 8, causes itself. A feeler roller can run on this. fen, which reaches the spring forces with contact and other follower members 40, as in the case of the opening known type for the control of the working cylinder described known design with spring-loaded is provided. loaded tappets is not the case. The invention is explained below with the aid of one. In the embodiment according to FIG. 4, there is only one the drawing illustrated and somewhat schema control cam 25 required. This is where the un- tized embodiment explained. It shows 45 tere end of a rotating arrow here, for example 1 shows the device according to the invention in the shaped knife 26. As can be seen from the dashed lines Side view, partially cut open, borrowed, is also here when moving the control Fig. 2 shows the cutting device from Fig. 1 with in body 8 a pivoting forward of the flow the inner mandrel swiveled cutting knife, resistance forming tip 27 of the knife in F i g. 3 effects the same cutting device with the inner dome removed, pivoted cutting knife, as can be seen from the exemplary embodiment, 4 shows a cutting device with a different shape, the solution according to the invention for the ter control cam and cutting knife. actual slitting process by just a few According to FIG. 1, the plastic mass produced by a plastic press and for this purpose simply designed and easily manufactured of any type emerges over the 55 parts. It is also easy to see that the flange connection 1 is inserted into the angled injection head 2. The cutting knife, in particular in the form of the measuring device, is then passed through an annular channel to the outlet 13 from FIG. 1, as well as the control cams very flat mouthpiece 3 out. This is formed from which and can be designed elongated. As a result, calibration tube 4 and an inner mandrel, which is the new slot device also for tubes verden parts 5 and 6. At the front end has 60 reversible, which has a very small inner diameter, the part 5 has a central bore 7 in which the.
Control body 8 is located. The latter has two control cams 9 and 10. In these, noses 11 and 12 slide.
of the cutting knife 13, which is pivotably mounted at 14. 65 1. Device for slitting plastic The control body 8 is in permanent connection with pipes, in particular for drainage purposes, in the a tube 15 guided centrally in the inner mandrel, the tube in an annular gap between a This is guided via sealing members 16 and 17 in the inner calibration tube and an inner mandrel