Patent Description:
More particularly, the invention relates to an apparatus for the orbital cutting of pipes of different thickness and diameter and made of plastic material, resin, composite material, or of any other material suitable for the manufacture of pipes for the distribution and dispensing of liquids and/or gaseous fluids.

As is known, pipes of the type described above are generally made monolithically, for example by extrusion or molding, and are cut into pipe segments of predetermined length that, if necessary, are shortened to size in order to obtain the dimensions required in each instance for the intended use.

The cutting operation is often performed at the building site and during installation, in order to obtain segments that are then joined with various methods, such as interlocking and/or fusing, both to provide new ducts and to maintain existing ducts.

The most commonly used apparatuses for pipe cutting are those that utilize circular sawing machines for woodcutting that, by suitable anchoring and guiding systems, are turned with an orbital motion around the pipe.

<CIT> discloses a portable and dismountable self centering orbital pipe cutter having two double opening cradles equipped with an integrated and removable connector for forming rigid assembling associated with a centering saddle. The saddle has radial gauges arranged in contact with internal or external surface of a pipe to be cut, and is provided with two straps for fixing the pipe. The cradles are equipped with telescopic hydraulic jacks and manual jacks terminated by support pads.

<CIT> discloses a municipal common water pipe cutting device having a chuck, a support and an electric saw; the chuck clamps a water pipe; the support is mounted on the chuck; and the electric saw is mounted on the support. The chuck comprises a lower chuck, an upper chuck, a guide rail, lower flanges, screw rods, upper flanges and a positioning hole; the lower chuck and the upper chuck are spliced into the whole chuck; and the water pipe is clamped by the chuck. The guide rails are arranged at the side parts of the lower chuck and the upper chuck; and the guide rail of the lower chuck and the guide rail of the upper chuck are combined into a circular rail. The lower flanges are arranged on the two sides of a lower connector, a screw rod is arranged on the lower flange on each side, the upper flanges are arranged on the two sides of the upper chuck, through holes are formed in the upper flanges, the number and the positions of the through holes correspond to those of the screws, the lower chuck and the upper chuck are connected and fixed through threaded fasteners, and the positioning hole is formed in the side face of a guide rail of the upper chuck.

<CIT> discloses a pipe cutter of a circumferentially cutting type including an annular base adapted to encircle the pipe to be cut and carrying clamping elements for clamping it non rotatively to the pipe, with an annular rotor rotatively mounted by this base and which is also adapted to encircle the pipe. A is cutting tool adapted to work inwardly against the pipe. This pipe cutter has an apparatus for transmitting rotative force to the rotor from the annular base, the latter thereby transmitting the reaction to the pipe itself. Thus the device may be a self-contained unit which may be used to cut the pipe circumferentially without the need of other apparatus such as a pipe clamp or vise which might otherwise be required to hold the pipe against rotating with the cutting tool.

<CIT> discloses an industrial pipe cutting using a rolling wheel cutting assembly affixed to a tool slide assembly of a split ring pipe cutter.

Those types of apparatus, despite being widely used, are not however free from drawbacks.

First of all, as a consequence of any deformation or ovalization of the pipe, the cut performed is often not perpendicular to the axis of the pipe, or the starting and end points of the cut do not coincide, consequently creating steps.

Moreover, the advancement of the sawing machine is manual and is performed by one or two operators who are forced to remain proximate to the cutting region, making this operation potentially dangerous.

The aim of the present invention is to provide a pipe cutting apparatus that overcomes the drawbacks of the cited prior art.

Within the scope of this aim, a particular object of the invention is to provide an apparatus that allows to perform cuts that are perfectly perpendicular to the axis of the pipe.

A further object of the invention is to provide an apparatus that allows to perform clean and precise cuts, in which the cut starting and end points coincide without creating any step.

A further object of the invention is to provide an apparatus that is capable of compensating for any deformation or ovalization of the pipe.

A further object of the invention is to provide an apparatus that allows to perform cuts that are not contaminated by lubricants or other substances.

A further object of the invention is to provide an apparatus that allows to perform cuts in complete safety, preserving the safety of the operators who perform the various process steps.

This aim and these objects, as well as others which will become better apparent hereinafter, are achieved by a pipe cutting apparatus as defined in claim <NUM>.

Further characteristics and advantages will become better apparent from the description of a preferred but not exclusive embodiment of a pipe cutting apparatus according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:.

With reference to the cited figures, the pipe cutting apparatus according to the invention, generally designated by the reference numeral <NUM>, has a substantially rigid annular frame <NUM> adapted to be coupled to a pipe <NUM> to be cut, a means <NUM> for cutting the pipe <NUM> which is associated detachably with the annular frame <NUM>, and a movement means <NUM> adapted to move the cutting means <NUM> with respect to the annular frame <NUM> about an axis of revolution <NUM> which is designed, during use, to substantially coincide with the longitudinal axis <NUM> of the pipe <NUM>.

The annular frame <NUM> completely surrounds the pipe <NUM> and is associated thereto with a preset position and inclination with respect to the longitudinal axis <NUM>, by means of a plurality of clamp plates <NUM> for contact with the outer face of said pipe <NUM>.

The clamp plates <NUM> can be actuated individually and can move on command, for example by means of threaded members <NUM>, radially toward the axis of revolution <NUM> and/or radially away from said axis, as shown substantially in <FIG>.

In this manner it is possible to compensate for any ovalization or deformation of the pipe <NUM> and to fix thereto the annular frame <NUM> so as to make the axis of revolution <NUM> substantially coincide with the longitudinal axis <NUM>.

Preferably, the clamp plates <NUM> are arranged symmetrically with respect to the axis of revolution <NUM> and are evenly angularly distributed along the circumference formed by the annular frame <NUM>.

Advantageously, the annular frame <NUM> is formed by two or more frame members which are shaped like an annular sector and can be connected to each other by virtue of an adapted mating means <NUM>, which can include for example screws <NUM>.

In the embodiment shown by way of example, the frame members are two, designated respectively by the reference numerals 2a and 2b, and are substantially semicircular.

This last characteristic is particularly advantageous, for example, if the pipe <NUM> is part of a continuous line, since it allows to couple the annular frame <NUM> along any point of the pipe <NUM> and therefore not necessarily at the terminal portion thereof.

In the embodiment shown by way of example, the apparatus <NUM> includes two annular rails <NUM> which are mutually parallel and spaced and are an integral part of the structure of the annular frame <NUM>.

However, the person skilled in the art may understand that the apparatus <NUM> could have an annular frame <NUM> with a structure of its own to which the annular rails <NUM> are coupled, or could have a different number of annular rails <NUM> (one or more than two).

In the shown example, each annular rail <NUM>, being an integral part of the annular frame <NUM>, is divided into two rail members, designated respectively by the reference numerals 9a and 9b, which are substantially semicircular or more generally shaped like an annular sector.

The rail members 9a and 9b are mutually joined by the mating means <NUM> which, in addition to ensuring the connection between the two members, allows to avoid interrupting the continuity of the circumferential profile of each annular rail <NUM> and to maintain the lateral alignment of the rail members 9a and 9b.

Preferably, interlocking shaped portions <NUM> are provided at the mating surfaces of the rail members 9a and 9b, as shown in <FIG>.

A carriage <NUM> which supports the cutting means <NUM> is associated slidingly and removably with the annular rails <NUM>.

In the embodiment illustrated by way of example, the carriage <NUM> has a body which is monolithic or formed by parts that are rendered mutually integral so as to avoid mutual separation, and straddles the outer cylindrical edge <NUM> of the annular rails <NUM>, which are partially inserted in a substantially rectangular opening <NUM> provided in the body of the carriage <NUM>.

Preferably, at least two sides of the opening <NUM> there are sliders <NUM> which render the mating between the carriage <NUM> and the annular rails <NUM> particularly fluid with minimal play.

Conveniently, the carriage <NUM> is provided with engagement members <NUM> which can engage selectively the annular rails <NUM>.

In the embodiment illustrated by way of example, the engagement members <NUM> include a pair of rollers <NUM> keyed on a shaft <NUM>, which is mounted rotatably on the carriage <NUM> about a first axis of rotation <NUM> which is substantially parallel, in use, to the axis of revolution <NUM>.

Each roller <NUM> preferably has a circumferential groove <NUM> designed to engage by rolling with the outer cylindrical edge <NUM>, i.e., the edge that is distal with respect to the axis of revolution <NUM>, of a corresponding annular rail <NUM>.

The engagement members <NUM> furthermore include two pairs of pins <NUM> which are accommodated in respective seats <NUM> provided in supporting members <NUM> which are mounted so that they can slide on the carriage <NUM>.

The pins <NUM> can rotate with respect to second axes of rotation <NUM>, which are substantially mutually parallel despite not necessarily coinciding, and are also parallel, in use, to the axis of revolution <NUM>.

The pins <NUM> can slide axially with respect to the second axes of rotation <NUM> and their sliding can be prevented, for example, by means of adapted retention members <NUM>, which can move transversely to said axes between a locking position and a release position.

When the carriage <NUM> is mated with the annular rails <NUM>, the pins <NUM> are designed to engage by rolling with an inner cylindrical edge <NUM>, i.e., an edge which is proximal with respect to the axis of revolution <NUM>, of the annular rails <NUM>.

In practice, the rollers <NUM> and the pins <NUM> respectively engage the two opposite peripheral edges <NUM> and <NUM> of the annular rails <NUM>, with the first axis of rotation <NUM> and the second axes of rotation <NUM> arranged substantially like the vertices of a triangle.

Advantageously, the supporting members <NUM> can move with respect to the carriage body <NUM> away from and toward each other.

The mutual approach of the supporting members <NUM> allows to facilitate the mating of the carriage <NUM> with the annular rails <NUM>.

The mutual spacing of the supporting members <NUM> allows to stable the mating between the carriage <NUM> and the annular rails <NUM>, reducing the radial plays with respect to the axis of revolution <NUM> between the two components of the apparatus <NUM>.

Preferably, the supporting members <NUM> are joined to the body of the carriage <NUM> by virtue of screw members <NUM>, which engage in slotted through holes <NUM> provided in the body.

Thus, by tightening or loosening the screw members <NUM> it is possible to respectively block the supporting members <NUM> to the carriage <NUM> or release their sliding within a stroke that is delimited by the slotted through holes <NUM>.

In the embodiment illustrated by way of example, the cutting means <NUM> includes a sawing machine <NUM>, of the type commonly commercially available.

The sawing machine <NUM> is mounted on the carriage <NUM> so that it can move on command radially toward the axis of revolution <NUM> and/or radially away from it.

Preferably, the sawing machine <NUM> is hinged to the body of the carriage <NUM> about a pivoting axis <NUM> which is substantially parallel, in use, to the axis of revolution <NUM>.

The adjustment of the angular position of the sawing machine <NUM> can be achieved, for example, by acting on a locking/release handle <NUM>.

The sawing machine <NUM> is equipped with a cutting disk <NUM> which is mounted on a shaft turned by a first motor <NUM>, for example of the electric type, about a third axis of rotation <NUM> which is substantially parallel, in use, to the axis of revolution <NUM>.

The oscillating motion of the sawing machine <NUM> about the pivoting axis <NUM>, i.e., with respect to the carriage <NUM> mated with the annular rails <NUM>, allows to make the cutting disk <NUM> sink to a greater or smaller extent into the thickness of the pipe <NUM>, as shown in <FIG> and <FIG>.

The sawing machine <NUM> is also provided with an orbital motion around the axis of revolution <NUM>, i.e., around the pipe <NUM>, which is obtained by virtue of the movement means <NUM> which interacts with the carriage <NUM>.

The movement means <NUM> includes a first transmission member <NUM> which is mounted rotatably on the carriage <NUM>, about the first axis of rotation <NUM>, and a second fixed transmission member <NUM>, which is coupled to the annular frame <NUM>.

Preferably, the first transmission member <NUM> is constituted by a pinion <NUM>, preferably of the roller type, which is integral with the shaft <NUM>, which is turned about the first rotation axis <NUM> by a second motor <NUM>, for example of the electric type, supported by the carriage <NUM>.

In the embodiment illustrated by way of example, the pinion <NUM> is obtained by winding and welding a chain around the shaft <NUM>, but in alternative embodiments, not shown, it might be provided differently.

The second transmission member <NUM> instead essentially consists of a ring gear <NUM> provided with teeth adapted to engage in succession the rollers of the pinion <NUM>.

Preferably, the ring gear <NUM> is an integral part of the annular frame <NUM> and therefore it, too, is divided into two ring gear members, designated by the reference numerals 34a and 34b respectively, which are substantially semicircular or more generally shaped like an annular sector.

The ring gear members 34a and 34b are mutually joined by virtue of the mating means <NUM>, which are configured so as to avoid interrupting the continuity of the pitch of the set of teeth of the ring gear <NUM> and maintain the lateral alignment of the ring gear members 34a and 34b, as shown substantially in <FIG>.

The operation of the pipe cutting apparatus according to the present invention is as follows.

In a preliminary step of preparation of the apparatus <NUM> for the cut required by the specific process, the annular frame <NUM> is associated with and coupled to the pipe <NUM>, as shown substantially in <FIG> and <FIG>.

Functionally, assuming that initially the clamp plates <NUM> are in the position of maximum radial spacing from the axis of revolution <NUM>, the association of the annular frame <NUM> with the pipe <NUM> occurs by arranging the two frame members 2a and 2b around it and by joining them by virtue of the mating means <NUM>.

If the cut is to be performed at or proximate to the end portion of the pipe <NUM>, the operation of mating the two frame members 2a and 2b so as to form a single body does not necessarily have to occur astride the pipe <NUM> but can also be performed separately, associating the annular frame <NUM> with it at a later time.

Once the annular frame <NUM> is correctly fitted over the pipe <NUM>, the clamp plates <NUM> are moved radially closer to the axis of revolution <NUM>, trying to make said axis coincide substantially with the longitudinal axis <NUM> of the pipe <NUM> and to compensate for any ovalization or deformation of the pipe.

This operation is performed by acting on the threaded members <NUM>, which by rotating modify the radial position of the clamp plates <NUM> until they rest with a slight pressure against the outer face of the pipe <NUM>.

When the annular frame <NUM> is coupled correctly to the pipe <NUM>, the carriage <NUM> and the sawing machine <NUM> are associated with it, as shown substantially in <FIG>.

Beforehand, the pins <NUM> are retracted into the respective seats <NUM>, completely freeing the opening <NUM>, and to move mutually closer the supporting members <NUM>, loosening the screw members <NUM> and making them slide in the slotted through holes <NUM> until the supporting members <NUM> are brought to their minimum mutual distance.

At this point, the carriage <NUM> is arranged astride the annular frame <NUM>, partially inserting the annular rails <NUM> in the opening <NUM>, until the outer cylindrical edge <NUM> of each rail is engaged in the circumferential groove <NUM> of the corresponding roller <NUM> and the teeth of the ring gear <NUM> engage in the openings formed in the pinion <NUM> by the chain.

Subsequently, the pins <NUM> are extracted from the respective seats <NUM>, making them protrude from the supporting members <NUM> toward the inside of the opening <NUM>, as shown substantially in <FIG>.

The position of the pins is then locked by means of the retention members <NUM> and the supporting members <NUM> are moved mutually apart by making the screw members <NUM> slide in the slotted through holes <NUM> until the supporting members <NUM> are moved to the maximum possible mutual distance, i.e. so as to engage the pins <NUM> with the inner cylindrical edge <NUM> of the annular rails <NUM>, eliminating plays completely.

With the tightening of the screw members <NUM>, the operations required to associate the cutting means <NUM> with the annular frame <NUM> substantially end and it is possible to start the operations for cutting the pipe <NUM>.

The sawing machine <NUM> is thus started, by supplying power to the first motor <NUM>, and moved toward the axis of revolution <NUM>, making it oscillate about the pivoting axis <NUM>.

When the cutting disk <NUM> sinks into the wall of the pipe <NUM> until it crosses its thickness completely, the position of the sawing machine <NUM> with respect to the carriage <NUM> is locked by acting on the handle <NUM>.

At this point, the second motor <NUM> is also powered and, by means of the continuous rolling of the pinion <NUM> on the ring gear <NUM>, causes the advancement of the carriage <NUM> and the sawing machine <NUM> along the circumference of the pipe <NUM> with an orbital motion.

Once the sawing machine <NUM> has performed a full rotation about the pipe <NUM> and has completed the cut, the second motor <NUM> and the first motor <NUM> are turned off.

In this condition it is possible to separate the carriage <NUM> from the annular frame <NUM> and the annular frame <NUM> from the pipe <NUM> with operations which are the reverse of the ones described previously.

In practice it has been found that the invention achieves the intended aim and objects, providing a pipe cutting apparatus which, also by the presence of a rigid annular frame that guides the orbital motion of the sawing machine, allows to perform cuts that are perfectly perpendicular to the axis of the pipe.

Also, in this manner the cuts are clean and precise and the cut starting and end points coincide without creating any step.

A further advantage is that the apparatus according to the present invention is capable of compensating for any deformation or ovalization of the pipe.

A further advantage is that the cuts are not contaminated by lubricants or other substances.

It should also be considered that the apparatus according to the present invention allows to perform cuts in total safety for the operators.

Claim 1:
A pipe cutting apparatus, comprising a substantially rigid annular frame (<NUM>) adapted to be coupled to a pipe (<NUM>) to be cut; a cutting means (<NUM>) for cutting said pipe (<NUM>) being removably associated with said annular frame (<NUM>), and a movement means (<NUM>) adapted to move said cutting means (<NUM>) with respect to said annular frame (<NUM>) about an axis of revolution (<NUM>) configured to substantially coincide with the longitudinal axis (<NUM>) of said pipe (<NUM>); said annular frame (<NUM>) comprising at least one annular rail (<NUM>) which comprises two or more rail members (9a, 9b) shaped as an annular sector, said rail members (9a, 9b) being connectable to each other by mating means (<NUM>) so as not to break the continuity of the profile of said annular rail (<NUM>) and maintain the lateral alignment of said rail members (9a, 9b); said cutting means (<NUM>) comprising a carriage (<NUM>) that is slidingly and removably associated with said annular rail (<NUM>); said carriage (<NUM>) having engagement members (<NUM>) which can selectively engage said annular rail (<NUM>); said engagement members (<NUM>) comprising at least one pair of pins (<NUM>) rotatably mounted on said carriage (<NUM>) about second axes of rotation (<NUM>) which are substantially parallel to said axis of revolution (<NUM>); said pins (<NUM>) being adapted to engage an inner cylindrical edge (<NUM>) of said annular rail (<NUM>); said apparatus being characterized in that said pins (<NUM>) are accommodated in respective seats (<NUM>) formed on supporting members (<NUM>) slidingly mounted on said carriage (<NUM>); said pins (<NUM>) being rotatable with respect to said second axes of rotation (<NUM>) and being able to slide selectively with respect to said second axes of rotation (<NUM>).