EP1702730A1

EP1702730A1 - Cutting assembly for continuously cutting plastics material pipe lenghts

Info

Publication number: EP1702730A1
Application number: EP05015284A
Authority: EP
Inventors: Achille Merlett Tecnoplastic S.p.a. Crugnola
Original assignee: Merlett Tecnoplastic SpA
Current assignee: Merlett Tecnoplastic SpA
Priority date: 2005-03-18
Filing date: 2005-07-14
Publication date: 2006-09-20
Anticipated expiration: 2025-07-14
Also published as: ATE407774T1; DE602005009655D1; EP1702730B1; ES2314524T3; DK1702730T3; ITMI20050453A1

Abstract

The present invention relates to a cutting assembly for continuously cutting plastics material pipe lengths, comprising, on a bearing framework, at least a cutting unit including gripping means for gripping a tubular element, the gripping means being associated with cutting means for cutting the tubular element and means for blowing pressurized air into the tubular element, to hold its gauge or calibrated size.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a cutting assembly for continuously cutting plastics material pipe lengths.
As is known, in methods for making plastics material flexible hoses such as, for example, irrigating, garden, aerodynamic use, pressurized air, shower use hoses and the like, is conventionally used pressurized air which is supplied by the extruding head or optionally by a dedicated nozzle assembled on the coil winder, operating to hold at a desired value the tube or pipe gauge.
This operation is performed to hold the tube or pipe in an inflated condition and to assure a constant size and, moreover, to apply outer layers, metal or plastic coils, and the like.
This approach is affected by a great drawback, deriving from the impossibility of cutting in-line the product into product or pipe lengths, but actually, the tubular product can be exclusively wound into coils of a comparatively high variable length.
This involves a great production complexity, with a consequent high increase of the cost.
In fact, the tubes or pipes to be sold in lengths are subjected to a subsequent cutting operation by using very expensive automatic cutters.
Moreover, the tube or pipe, which is made in a coil arrangement and successively cut into pipe lengths, is frequently affected by a great ovalization, due to the fact that the tubular material is wound up as it is in a still hot condition.
Actually, the requirement of providing pressurized air inside said pipe does not allow to perform an exchange between a pipe length and a following pipe length, with a high frequency, since, in conventional methods, the tube would be inflated and a comparatively high amount of defective tubular material would be produced.

SUMMARY OF THE INVENTION

Accordingly, the aim of the present invention is to overcome the above mentioned problem, by providing a cutting assembly for continuously cutting plastics material tube lengths, which allows to provide preset length tubes, while holding a constant pressure inside the tube, to achieve an optimum production yield.
Within the scope of the above mentioned aim, a main object of the present invention is to provide such a cutting assembly allowing to make pipe or tube lengths which can be cut with a high frequency and which are provided in a ready for packaging condition.
Another object of the present invention is to provide such a cutting assembly which, owing to its specifically designed characteristics, is very reliable and safe in operation.
Another object of the present invention is to provide such a cutting assembly which is very simple construction wise and which, moreover, is very competitive from a mere economic standpoint.
According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a cutting assembly for continuously cutting plastics material tube lengths, characterized in that said cutting assembly comprises, on a bearing framework, at least a cutting unit including gripping means for gripping a tubular element, said gripping means being coupled to cutting means for cutting said tubular element and pressurized air blowing means for blowing pressurized air into said tubular element to hold a set gauge thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of the invention which is illustrated, by way of an indicative, but not limitative example in the accompanying drawings, where:

Figure 1 is a schematic front elevation view illustrating the cutting assembly according to the present invention;
Figure 2 is a top plan view illustrating that same cutting assembly;
Figure 3 is an end view illustrating the cutting assembly;
Figure 4 is a cross-sectional view illustrating a cutting unit, in a rest or inoperative condition thereof;
Figure 5 is a perspective view of the cutting unit shown in a rest or inoperative condition thereof;
Figure 6 is a cross-sectional view illustrating the cutting unit in a cutting condition thereof; and
Figure 7 is a perspective view showing the cutting unit in a cutting condition or status thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the number references of the above mentioned figures, the cutting assembly for continuously cutting plastics material tube or pipe lengths, according to the present invention, which has been generally indicated by the reference number 1, comprises a bearing framework 2, which is arranged near an extruding head, therefrom exits a plastics material tubular element, which can be either flexible, half-rigid, or rigid.
A main feature of the present invention is that on the cutting framework are provided a first and second cutting units, which are respectively indicated by the reference numbers 3 and 4.
Each cutting unit comprises gripping means for gripping a tubular element 5 being extruded, said gripping means comprising a gripper element 10, the jaws of which define a slanted surface 11, thereon operates a clamping element 12, including wedge-like surfaces, which is driven by a first piston 13.
To said cutting unit a slider 20 is associated or coupled, said slider supporting a cutting blade 21 having a throughgoing hole 22 which is driven by the first piston 13 as a cutting operation is to be performed.
On said slider a nozzle 30 is supported, said nozzle being arranged at said hole 22 and being driven by a second piston 31 to be engaged inside said tube or pipe 5 after having performed the cutting operation.
On the bearing framework 2 are provided a first and second cutting units which operate alternately to engage with the tubular element, after having cut it, and to be driven therewith to the desired length.
After having achieved the set or desired length, a switching element 40 displaces the tubular element 5 to arrange it at the other cutting unit, which is arranged at the start portion.
Thus, it is possible to perform in succession a plurality of cuts, while holding a set air pressure inside the tube.
In operation, upon a preset command, the first piston 13 drives the slider 20, therewith is rigid the blade 21 including the throughgoing hole 22.
As said blade is driven, it operates the gripping gripper 10 which is clamped by the clamping element 12 which firmly holds the tubular element to be cut through.
As it achieves its end position, the cutting blade will present, at the hole of the cut tubular element, the throughgoing hole 22 of said blade.
At this time, the second piston 31 will operate, with a very high speed, the air inlet nozzle 30 for supplying air inside the cut tubular element.
Thus, the overall cutting unit can start to slide along an operating track defined on the bearing framework 2 to pass from the operating starting position, where the cutting operation is performed, to an end of cycle position, entraining with it the pipe as evenly inflated by pressurized air.
In the meanwhile, the other cutting unit, which is identical to the first cutting unit, will return to the operating cycle starting position, to be set for the following cutting operation.
Upon receiving an electric command, the first cutting unit will be stopped at an end of cycle position and will discharge the tube.
Simultaneously, the switching element 40 will bring the tube at the second cutting unit.
The second cutting unit, in particular, will cut through the tube in a precisely identical manner to the above disclosed operation.
More specifically, the first cutting unit causes the gripper to be opened, thereby discharging the tube length which is collected in a collecting region.
The operating cycle will start again and the first cutting unit will return to the cycle start position, whereas the second cutting unit will be driven with the cut through pipe or tube.
With the above disclosed embodiment, for each said operating step, the tubular element will be always held in a pressurized condition, owing to a quick exchanging between the first and second cutting assemblies or units.
From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects.
In particular, the fact is to be pointed out that the invention provides a cutting assembly having a very high production yield, which allows to make tubes and the tube lengths with an accurate size or gauge precision, since pressurized air is always held inside the tubular element.
Another important aspect of the invention is that it is possible to continuously control the product and its size, with a further advantage of fully eliminating the ovalization of the made tube lengths and the bending of the tube material deriving from the fact that it is collected into a roll.
The invention, as disclosed, is susceptible to several modifications and variations, all of which will come within the scope of the invention.
Moreover, all the constructional details can be replaced by other technically equivalent elements.
In practicing the invention, the used materials, as well as the contingent size and shapes, can be any, depending on requirements.

Claims

A cutting assembly for continuously cutting plastics material tube lengths, characterized in that said cutting assembly comprises, on a bearing framework, at least a cutting unit including gripping means for gripping a tubular element, said gripping means being associated with cutting means for cutting said tubular element and pressurized air blowing means for blowing air into said tubular element to hold at a set value the gauge thereof.
A cutting assembly, according to the preceding claim, characterized in that said gripping means comprise gripper means having a jaw pair including a slanted surface for engagement with clamping means.
A cutting assembly, according to the preceding claims, characterized in that said clamping means are slidably driven by a first piston.
A cutting assembly, according to one or more of the preceding claims, characterized in that said cutting assembly comprises a slider supporting said cutting means and said air blowing means.
A cutting assembly, according to one or more of the preceding claims, characterized in that said cutting means comprise a blade having a throughgoing hole at said air blowing means.
A cutting assembly, according to one or more of the preceding claims, characterized in that said cutting assembly further comprises a nozzle which can be engaged in an end portion of a cut tube and can be driven so as to be engaged in said tubular element by a second piston coupled to said slider.
A cutting assembly, according to one or more of the preceding claims, characterized in that said cutting assembly comprises a first and second cutting units, which are alternately movable on said bearing framework from an operating cycle starting position to an operating cycle end position and vice versa.
A cutting assembly, according to one or more of the preceding claims, characterized in that said cutting assembly comprises a switching device for alternately engaging said tubular element with said first and second cutting unit.
A cutting assembly for continuously cutting plastics material tube lengths, according to one or more of the preceding claims, and substantially as broadly disclosed and illustrated, and for the intended aim and objects.