DESCRIPTION

The present invention refers to a torque- controlled pipe expander particularly but non exclusively for the pipe expansion in heat exchangers and boilers.

Torque-controlled pipe expanders have long been present on the market, having a telescopic shaft controlling the rotation of the spindle which can be grasped by the operator through a knob.

The pipe expander is brought in suspension on a carriage in which the electronic controller is installed.

Generally a first translation axis and a second horizontal translation axis of the telescopic shaft can be provided, in order to assist the correct position of the spindle inside the pipe.

The two horizontal and vertical translation axes lie in a plane orthogonal to the axis of the telescopic shaft.

One of the main drawbacks of a traditional pipe expander of the aforementioned type consists in that the telescopic shaft is sometimes forced to remarkably extend axially in order to reach the correct working position, with the consequent risk of the occurring, during its rotation, of non negligible rotary eccentric masses which determine strong mechanical stresses and vibrations.

The pipe expander becomes in this way less safe for the operator and it is subjected to a more rapid deterioration of performance for the rapid wear to which its parts are subjected.

It is also known that such pipe expanders can lament a low flexibility of adaptation, and so they guarantee the joining of some working positions only by reducing their whole efficiency, being damaged by the high frictions determined in the axial and angular offsets formed among the jointed parts.

The loss of efficiency often is not exactly predictable, and varies from time to time with respect to the specific configuration in the junctions of the telescopic shafts, with the consequence that the pipe expander cannot be adapted in an automatic way for the execution of repeatable working cycles. The technical task of the present invention is therefore to realize a pipe expander with torque control, particularly for the pipe expansion in heat exchangers and boilers, permitting to eliminate the technical drawbacks lamented by the known technique.

One of the aims of this technical task is that to realize a pipe expander with torque control, particularly for the pipe expansion in heat exchanger or boilers having the maximum operating safety, a longer duration, an optimized efficiency and an intrinsic capability to sustain programmed cycles of working which can be repeated with the same efficiency.

Another task of the invention is to realize a pipe expander with torque control, particularly for the pipe expansion in heat exchangers and boilers, having a rapid piping cycle, a working uniformity, a strong, light and handy structure.

The technical task, and also these and other aims of the present invention are reached by realizing a pipe expander with torque control, particularly for the pipe expansion in heat exchangers and boilers, comprising an expander brought by a telescopic shaft actuated by a rotary motor sustained by a suspension device, applied to a carriage having an electronic controller of the pipe expander, characterized in that said rotary motor of the expander is supported by said suspension device in a movable way along the direction of the axes of the telescopic shaft.

Preferably the pipe expander with torque control comprises a rigid cover for the joint at a swivel joint between the telescopic shaft and the mandrel.

Preferably the covering handle of the expander for its handling has a safety element with a control manual releasable for the actuation of a stop switch of the rotary motor.

Preferably the safety element comprises a pivoted lever to the handle.

Preferably the pipe expander comprises an elastic tensioner able to maintain the concentricity between the telescopic shaft and the mandrel.

Preferably the elastic tensioner comprises a helical spring mounted on thrust bearings.

Preferably the suspension device has a first support element sustained by the carriage in a translational way, towards a first axis of translation, a second support element sustained by said first support element in a translational way towards a second axis of translation orthogonal to the first axis of translation, a third element of support sustained by said second support element in a rotary way around a first rotary axis parallel to said second axis of translation, a fourth support element sustained by said third support element in a translational way towards a third axis of translation orthogonal to said first rotary axis, the group comprising said rotary motor, said telescopic shaft and said expander being suspended to said fourth support element in a rotary way around a second rotary axis orthogonal to said first rotary axis.

Preferably the group comprising said rotary motor, said telescopic shaft and said expander is balanced with respect to the second rotary axis.

Preferably between the group comprising said rotary motor, said telescopic shaft and said expander and the fourth support element a first potentiometer is inserted, for the actuation of a first regulating motor of the position of the group, by means of said movement of said second support element along said first support element.

Preferably between said third support element and said second support element a second actuating potentiometer of the position of the group is inserted, comprising said rotary motor, said telescopic shaft and said expander by means of a displacement of said first support element along said carriage.

Preferably the carriage brings a seat for the operator.

Preferably a torque detector is present, resistant to the rotation of the expander, linked to the electronic controller and able to generate a stop signal of the rotary motor, when the detected resistant torque suddenly drops before reaching the threshold set.

Further characteristics and advantages of the invention will be clearer from the description of a preferred but non exclusive embodiment of the pipe expander with torque control according to the founding, shown in an indicative and non limited way in the annexed drawings, in which: Figure 1 shows a front view of the pipe expander;

Figure 2 shows a top side view of the pipe expander; and

Figure 3 shows a top side view of the group formed by the expander and the telescopic shaft and respective rotary motor provided with an element for its support in suspension, in the retracted position both of the group and the telescopic shaft;

Figure 4 shows a front view of the group in Figure 3 in the same position;

Figure 5 shows a top side view of the group formed by a telescopic shaft and its respective rotary motor provided with an element for its support in suspension, in the protruding position both of the group and the telescopic shaft;

Figure 6 shows a front view of the group in Figure 5 in the same position.

With reference to the cited figures, a pipe expander with torque control is shown, in particular for the expansion of pipes in heat exchangers and boilers, globally indicated with the reference number 1. The pipe expander 1 comprises an expander 1 brought by a telescopic shaft 2 sustained by a suspension device 3 applied to a carriage 4 having an electronic controller 5 of the expansion.

Advantageously the rotary motor 6 of the expander 1 is supported by the suspension device 3 in a movable way along the L direction of the axis of the telescopic shaft 2. The handling of the rotary motor 6 along the axis L is made manually or even by means of a not shown motor.

The carriage 4 has wheels 7 and hydraulic small lifting feet 8, in order to guarantee a rapid displacement of the pipe expander 1.

The suspension device 3 has a first support element 9 sustained by the carriage 4 in a translational way and towards a first translation axis S.

A second support element 10 is sustained by the first support element 9 in a translational way towards a second translation axis T orthogonal to the first translation axis S.

A third support element 11 is supported by the second support element 10 in a rotary way around a first rotary axis around a first rotary axis R parallel to the second translational axis T.

A fourth support element 29 is sustained by the third support element 11 in a translational way towards a third translational axis V orthogonal to the first rotary axis R.

The group 30 comprising the rotary motor 6, the telescopic shaft 2 and the expander 1 is sustained to the fourth support element 29 in a rotary way around a second rotary axis U orthogonal to the first rotary axis R.

The group 30 can therefore be handled according to handling axes comprising dropping the first translational axis S, the second translational axis T, the first rotary axis R, the third translational axis V, and the second rotary axis U.

In particular, the first translational axis S is horizontal and orthogonal to the third translational axis V also horizontal, the second translational axis T is vertical _/ the first rotary axis R is vertical and the second rotary axis U is horizontal. The displacement of the group 30 along the first translational axis S determines its linear right/left position, the displacement of the group 30 along the second translational axis T determines its linear high/low position, the displacement of the group 30 along the third translational axis V determines its linear back and forth position, the displacement of the group 30 along the first rotary axis determines its angular right/left position, and the displacement of the 30 along the second rotary axis U determines its angular high/low position.

The distribution of the masses in the group 30 is such that the group 30 is balanced with respect to the second rotary axis U. The telescopic shaft 2 comprises a first grooved part 2a integrally in translation and in rotation with the shaft 16 of the motor outlet 6 and a second part 2b sliding towards the axis L along the first part 2a with which it is integrally in rotation.

The second part 2b of the telescopic shaft 2 is coaxially covered by a protective tubular shirt 18 from which it is separated by means of suitable rotary bearings.

The protective shirt 18 is therefore integral in translation towards the axis L with the second part 2b of the telescopic shaft 2 but it is released from the rotation of the second part 2b of the telescopic shaft 2.

In order to avoid, especially when the telescopic shaft 2 is protruded, that the weight of the expander 1 and of the second part 2b of the telescopic shaft 2 be a full burden on the first part 2a of the telescopic shaft 2 by exerting an excessive bending moment, the protective shirt 18 has a flange 31 to which two or more support bars 32 are fixed, supported in a translational way towards the axis L in sliding holes 33, present in the group 30 on the bracket 34 sustaining the rotary motor 6.

The expander 1 comprises a bar la having at one of its ends a working head lb.

The bar la is coaxially covered by a coaxially hollow handle 14 apt to the handling of the expander 1.

Suitable rotary bearings separate the bar la from the handle 14 which therefore does not rotate during the rotation of the expander 1.

The handle 14 has a wider base 13 at the end of the bar la of the expander, directed towards the telescopic shaft 2.

The working head lb on the contrary is disposed outside the axial end of the handle 14, opposed to that in which the wider base 13 is present.

The telescopic shaft 2 is linked by means of an offset joint 12 to the bar la.

A rigid lug 17 is provided at the offset joint 12 and has a superimposed length with respect to the outer shirt 18 of the telescopic shaft 2.

The lug 17 is fixed to the base of the handle 14.

A protective bellows housing 19 for the covering of the first part 2a of the telescopic shaft 2 is fixed between the flange 31 and the lug 35 of the joint 36 between the outlet shaft 16 of the rotary motor 6 and the first part 2a of the telescopic shaft 2.

The lug 35 is separated by means of rotary bearings from the outlet shaft 16 and from the first part 2a of the telescopic shaft 2 and it is fixed to the bracket 34.

By providing in a sequence the handle 14, the lug 17, the shirt 18 and the protective cover 19 a continuous and complete cover of all the rotary parts is formed, with the exception of the working head lb of the expander 1, in order to use the expander in a regime of total safety for the operator.

In order to further increase the characteristics of safety, the handle 14 has a safety element 20 with a manual control, releasable for the actuation of a stopping switch 21 of the rotary motor 6.

The safety element 20 comprises a pivoted lever 22 in 37 with respect to the handle 14 at its end zone, from which the working head lb of the expander 1 protrudes.

The lever 22 axially develops along the handle 14 and it has a free shaped end 23 facing the switch

21 incorporated in the base 13 of the handle 14.

When the operator holds the handle 14, the lever

22 necessarily engages with its free shaped end 23 with the switch 21, which commutes in this way by generating an actuation signal of the electric supply of the rotary motor 6.

When for an illness or another accidental cause the operator leaves the handle 14 the lever 22 by means of a return spring (not shown) automatically returns in a position in which its free shaped end 23 disengages from the switch 21, by effecting again a commutation in a state in which a stopping signal of the electric supply of the rotary motor € is generated.

Advantageously, between the shirt 18 and the base 13 of the handle 14 an elastic tensioner 24 is present, able to maintain the coaxial state between the telescopic shaft 2 and the expander 1.

The elastic tensioner 24 in this case comprises a helical spring 25 housed on the offset joint 12 and supported on its first axial end to the base 13 of the handle 14 and on its second axial end to a flange 26 inside the shirt 18.

The spring 25 is mounted on thrust bearings apt to avoid their rotation.

The elastic tensioner 24 helps the operation without having to sustain the weight of the expander in the applications in which an angle between the expander 1 and the telescopic shaft 2 is required, and having only to overcome the slight elastic force applied in a transversal direction from the elastic tensioner 24 in order to direct correctly the expander 1 with respect to the telescopic shaft 2 in an application where this is necessary.

Advantageously, between the group 30 and the fourth support element 29 a first potentiometer 27 of a particular rotary type is inserted, for the actuation of a first motor (not shown) for regulating the position of the group 30 by means of a displacement of the second support element 10 along the first support element 9.

Advantageously, also between the third support element 11 and the second support element 10 a second potentiometer 28 is placed, also of a particular rotary type, for the actuation of a second motor (not shown) for regulating the position of the group by means of a displacement of the first support element 9 along the carriage 4.

The first potentiometer 27 and the second potentiometer 28 practically sustain the dragging action of the expander 1 actuated by the operator by means of the handle 14, in order to maintain the coaxial state between the expander 1 and the telescopic shaft 2. When the operator, by holding the handle 14 generates a horizontal and/or vertical angle between the expander 1 and the telescopic shaft 2, the first potentiometer 27 and/or the second potentiometer 28 pilot the respective motor in order to cause a displacement of the group 30, such to cancel the vertical and/or horizontal angle being formed.

In a non automatic version of the pipe expander the potentiometers 27 e 28 can also be absent, and the displacement of the pipe expander in vertical and in horizontal way, transversally to the advancing direction of the telescopic shaft is directly performed by the operator.

The operation of the pipe expander with a mainly coaxial disposition of the expander 1 with respect to the telescopic shaft, permits 2 an improvement of the efficiency for the reduction of losses, together with the rotary eccentric masses due to the possible translation by means of the rotary motor 6 in the L-direction of the telescopic shaft 2, and it reduces the wear and its difficult breaking of the parts, so increasing the duration of the device, and permitting a more precise and predictable detection of the torque resistant to the rotation of the expander 1, in such a way to make possible a final repeatable result, by means of setting programmed cycles for the expansion.

Advantageously _/ the pipe expander comprises a detector (not shown) of the torque resistant to the rotation of the expander 1, connected to the electronic controller 5 and able to generate a stopping signal of the rotary motor 6, when the detected torque drops immediately before having reached a preset threshold, for example due to the breaking of the working head lb of the expander 1.

The safety measures here shown guarantee a convenient and safe use of the pipe expander, at a suitable safety distance from the face of the operator.

In order to improve the convenience of use of the pipe expander also a seat 38 for the operator is provided, directly supported by the carriage 4.

The pipe expander with torque control so conceived is susceptible of various changes and modifications, all of them pertaining the concept of the invention; furthermore all the details can be replaced by technically equivalent elements. In practice the used materials, and also their size could be of any kind, according to the needs and to the state of the art.