Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
  • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
  • B26F1/0015—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor specially adapted for perforating tubes
  • B26F1/0023—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor specially adapted for perforating tubes by rotary tools, e.g. saws

Definitions

• the invention relates to a method and a device for cutting slots in tubular bodies.
• Double-walled corrugated pipes with a smooth inner hose, which is connected on the inside to the troughs by welding, are particularly critical. Slanted or laterally offset slots in the wave troughs can damage the weld and make the pipe unusable.
• the invention solves this problem with the features in the characterizing part of the main method and device claim.
• the invention proposes to intermittently transport the tubular body, in particular a single-wall or multi-wall corrugated tube, and to introduce the slots at the times when the tube is at a standstill. This has the great advantage that geometric errors in the insertion of the slots are practically excluded. There can also be no more damage to the welds on multi-wall corrugated pipes.
• the method according to the invention enables axially fixed knife shafts and thus also reliable detection of the pipe contour and exact guidance of the cutting knife.
• corrugated tubes can be slotted with any wave heights and spacings, with no kinematics constraints with regard to the number and distribution of the slots over the circumference and in the longitudinal direction. Every wave trough can be provided with slits, as well as every second, every third, etc.
• the method can be used for any types and materials of tubular bodies. It is particularly suitable for plastic corrugated pipes, preferably double-walled.
• the corrugated tube can alternatively also be single-walled or have any other design.
• the cutting device according to the invention has the advantage of simple kinematics of the knife shafts, which only rotate but do not have to move in the longitudinal direction.
• the knife shafts can therefore be constructed in a structurally simple manner and be sufficiently stable to absorb the cutting reaction forces. This also enables a reduction in cross-sections and a denser arrangement and distribution of the knife shafts around the tube.
• the knife shafts and the conveyor device are coordinated with each other in terms of drive and alignment.
• the knife shafts can rotate continuously.
• the conveyor can be designed differently, for example as an intermittent gripper.
• screw conveyors with straight and inclined passage sections are provided for corrugated pipes, which can also rotate continuously. With the sloping aisle sections, the pipe is transported while it is at The straight passage sections are engaged.
• This version has the advantage of a simple, compact and robust construction. It can be easily adapted and varied to different pipe shapes by varying the parameters of the knife shafts and screw conveyors.
• the cutting device can also be easily converted.
• the knife shafts and the screw conveyors have a common drive, into which a gear ratio may be switched on.
• the transport screws can also sit directly on the knife shafts, which minimizes the construction effort and size.
• multi-flight screw conveyors are used accordingly.
• the screw conveyors can also be catchy and quickly translated in relation to the knife shafts.
• the worm threads can have two or more straight sections.
• the angular positions and directions of rotation of the knife shafts are coordinated to optimize the cutting forces and cutting reactions.
• the straight aisle sections are preferably shorter than the oblique and just as long as is necessary for the engagement and the guidance of the cutting knives.
• the dimensions also depend on the pipe shape and the cutting specifications.
• the straight sections cover a circumferential angle between 70 ° and 100 ° depending on their number per gear. So that the protruding knife tips of adjacent shafts do not interfere with one another, they are axially offset from one another. The offset is based on the cutting specifications and also serves to make the slots in the troughs two or more times.
• Fig. 3 an end view of the knife shaft distribution
• Fig.4 a knife shaft in side view
• Fig. 5 u. 6 Cross sections through the knife shaft.
• the cutting device (1) shown in FIGS. 1 and 2 is used to cut slots (13) into the valleys of a corrugated pipe (2) with closed valleys and heights.
• the tube is designed as a double-walled corrugated tube (2) made of thermoplastic material with a smooth inner skin and a corrugated outer skin.
• Such a corrugated tube (2) is known for example from DE-OS 36 05 329.
• Corrugated pipes serve e.g. as a drain pipe for drainage or irrigation pipes.
• Fig. 1 and 2 illustrate the corrugated tube (2) on the input side for transport and arranged to be distributed outside the housing (12) has four screw conveyors (3) with longitudinal axes uniformly around the corrugated tube axis'.
• the tube (2) also engages in the form of conical friction rollers on the input side, which rotate about transverse axes and prevent the tube (2) from being undesirably twisted about its longitudinal axis.
• On the output side there are also two mutually opposing identical screw conveyors (3).
• the corrugated tube (2) is additionally guided on a flange (16). For a clearer representation, the corrugated tube (2) is only shown on the output side.
• the screw conveyors (3) have one or more gears.
• the screw conveyors (3) have straight passage sections (4) and inclined, i.e. helically wound passage sections (5).
• the individual worm threads each have the straight and inclined gear sections (4, 5) on the same circumferential area.
• the straight aisle sections (4) extend over a circumferential angle between 70 ° and 100 °.
• knife shafts (6) are evenly distributed in the housing (12) around the circumference of the tube.
• the knife shafts (6) extend along the transport direction (14) and are axially fixed so that they can only rotate about their longitudinal axis.
• a cutting knife (7) is arranged on each cutter shaft (6) and moves in a circular path.
• the knife shafts (6) are coupled to each other and to the feed screws (3) in terms of drive (see Fig. 1). They are driven from the outside by a drive wheel (11), for example via a chain drive.
• the individual cutter shafts (6) are driven by a drive shaft (15) and a transfer case arranged in the rear part of the housing (12).
• the drive for the screw conveyors (3) is derived from the shaft (15).
• the drive transmission is designed so that during the turning phase, in which the straight gear sections (4) are engaged and hold the tube (2), the knife shafts (6) cut the slots in the tube (2).
• all cutter shafts (6) are out of engagement, so that the tube (2) can be transported further by means of the inclined passage sections (5).
• the cutting knives (7) are axially offset from one another on adjacent knife shafts (6) so as not to collide with one another during one revolution.
• the offset is preferably directed alternately forwards and backwards. Its size depends on the corrugated pipe pitch and the desired slot spacing. If only every second wave trough is to be slit, the offset is correspondingly greater than with slitting each wave trough.
• the knife shafts (6) are also offset from one another in terms of their angle of rotation, ie the angular position of their cutting knives (7). Relative to the pipe axis (14) or the engagement position with the pipe (2), the offset is 180.
• the cutting knives (7) thus come into engagement with the tube (2) in two groups a and b.
• the knife shafts (6) also rotate alternately in opposite directions.
• the mutual assignment of the knife shafts is made in such a way that the reaction forces of the cutting knives (7) in engagement cancel each other out by none Initiate moments on the pipe (2). It is also advantageous if the angular positions of the knife shafts (6) are selected so that the same number of cutting knives (7) are always in engagement. 3 shows this knife position and the division of the knife shafts into two groups of the same size (6a and 6b).
• Fig. 4 - 6 illustrate the design of the knife shafts (6) in detail.
• a single cutting knife (7) protruding perpendicular to the shaft axis is arranged on each knife shaft (6).
• Guide fins (8) are arranged on both sides of the cutting knife (6) and in the angular position in the center thereof, which plunge into the adjacent troughs of the tube (2) simultaneously with the cutting knife (7) and ensure centering of the position.
• the fins (8) are curved on the outside and extend approximately over 1/4 of the shaft circumference.
• the fins (8) have a common, stepped foot part (9) with which they are inserted into a correspondingly recessed opening in the knife shaft (6).
• the foot section (9) is held in place by two countersunk screws on the outside.
• the cutting knife (7) is longitudinally displaceable with a similar foot part with an elongated hole within the foot part (9) and the knife shaft (6). Its immersion depth is set at the rear using a screw (17), while the knife body is clamped by means of a clamping screw (10).
• the knives are arranged in two groups offset by 180 ° analogous to the embodiment shown.
• every second wave trough is to be slit, a two-flight screw conveyor is used, in which each course, however, now has two straight sections of approx. 70 °, so that in the first stand break one knife group and in the second stand break the other knife group for engagement is coming.
• the screw conveyors can have two straight sections in one passage without geometric problems because of the smaller pitch. This means that a screw arrangement inside the housing is also possible.
• the transport screws have two gears, each gear having a straight section of approximately 100 over a 360 ° circumferential angle.
• the transport screws sit directly on the knife shafts and are arranged inside or outside the housing.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Milling Processes (AREA)
• Nonmetal Cutting Devices (AREA)
• Turning (AREA)
• Screw Conveyors (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6380113

Family Applications (1)

Country Status (5)

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Family Cites Families (11)

• 1989
  • 1989-05-05 DE DE19893914779 patent/DE3914779A1/de not_active Ceased
• 1990
  • 1990-05-02 EP EP19900906927 patent/EP0472551A1/de not_active Withdrawn
  • 1990-05-02 CA CA 2054685 patent/CA2054685C/en not_active Expired - Fee Related
  • 1990-05-02 WO PCT/EP1990/000704 patent/WO1990013400A1/de not_active Application Discontinuation
  • 1990-05-02 JP JP2506585A patent/JPH0710518B2/ja not_active Expired - Lifetime

Non-Patent Citations (1)

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