WO2010063515A1

WO2010063515A1 - Fluid-operated actuator with improved stroke limit adjustment means

Info

Publication number: WO2010063515A1
Application number: PCT/EP2009/064006
Authority: WO
Inventors: Antonio Marinoni; Ignazio Paris; Santo Rota
Original assignee: Air Torque SpA
Current assignee: Air Torque SpA
Priority date: 2008-12-04
Filing date: 2009-10-23
Publication date: 2010-06-10
Anticipated expiration: 2011-06-04
Also published as: ITMI20082150A1; IT1392075B1

Abstract

A fluid-operated actuator (1) with improved stroke limit adjustment means comprising a containment body (2) that forms a sliding chamber (3) of at least one piston (4) for the actuation of a control shaft (10) which can be associated with a valve to be driven. Stroke limit means are associated with the control shaft (10), inside the containment body (2), consisting of an elongated plate (20) that forms, on a first side, a cam-like profile provided with end portions (22) for providing stroke limits that are offset by -5° and +5° with respect to the theoretical open and closed positions of the valve. A central portion (23) is further provided for locking the valve open and closed. The plate (20) has, on a second side which is opposite to the first side, a second cam-like profile with end portions (24) that provide stroke limits which are offset by angles larger than the offset provided by the end portions of the cam-like profile.

Description

FLUID-OPERATED ACTUATOR WITH IMPROVED STROKE LIMIT

ADJUSTMENT MEANS

Technical Field

The present invention relates to a fluid-operated actuator with improved stroke limit adjustment means.

Background Art

As is known, with the fluid-operated actuators typically used for the remote actuation of valves and the like it is quite useful to be able to adjust the stroke limit position of the actuator and therefore of the valve on which said actuator is installed.

This solution allows optimization of the alignment between the flow control element of the valve and the several unions for connection of said actuator, thus achieving perfect alignment between the flow control element and the actuator itself. For achieving this function, a cam is normally provided which is connected to the actuation shaft and provides the stroke limit in the open and closed positions, with the possibility of adjustment by approximately 5° in both directions.

Moreover, in many situations, it is necessary to be able to lock the actuator in the open or closed position; therefore, the cam that is used, which allows adjustment by a few degrees for opening and closure, is usually provided with a central lug which makes it possible, by means of the external adjustment screws, to perform locking in the open and closed conditions. In other cases it is necessary to be able to adjust the rotation of the actuator with a relatively wide angular offset, and therefore in these cases it is necessary to use cams that are different from the ones that allow an offset of a few degrees.

With current solutions, there is, therefore, the need to have two different types of cam, which must be installed as a function of the contingent requirements; this causes problems in parts storage and the need to have both cam types available. Disclosure of the Invention

The aim of the invention is to solve the problems described above, by providing a fluid-operated actuator with improved stroke limit adjustment means, which makes it possible, with a single cam, to obtain angular offsets of a few degrees, locking, and the possibility of adjusting the stroke limit according to a very wide angular offset.

Within this aim, an object of the invention is to provide a fluid- operated actuator in which it is possible to lock in position the adjustment made, preventing inappropriate access to the stroke limit adjustment screws.

Another object of the present invention is to provide a fluid-operated actuator which, thanks to its particular constructive characteristics, is capable of giving the greatest assurances of reliability and safety in use. Another object of the present invention is to provide a fluid-operated actuator that can be obtained easily starting from commonly commercially available elements and materials and is also competitive from a purely economic point of view.

This aim and these other objects that will become better apparent hereinafter are achieved by a fluid-operated actuator with improved stroke limit adjustment means, according to the invention, comprising a containment body that forms a sliding chamber of at least one piston for the actuation of a control shaft which can be associated with a valve to be driven, stroke limit means being associated with said control shaft, inside said containment body, and consisting of an elongated plate that forms, on a first side, a cam-like profile provided with end portions for providing stroke limits that are offset by -5° and +5° with respect to the theoretical open and closed positions of said valve, a central portion being further provided for locking said valve open and closed, characterized in that said plate has, on a second side which is opposite to said first side, a second cam-like profile with end portions that provide stroke limits which are offset by angles that are larger than the offset provided by the end portions of said cam-like profile.

Brief Description of the Drawings Further characteristics and advantages of the present invention will become better apparent from the description of a preferred but not exclusive embodiment of a fluid-operated actuator with improved stroke limit adjustment means, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a perspective view of the fluid-operated actuator with the stroke limit means arranged for offset by a few degrees; Figure 2 is a plan view of the actuator of Figure 1; Figure 3 is a diagram of the extent of the angular offset for opening and closure; Figure 4 is a plan view of the actuator, with the stroke limit means in the locking position;

Figure 5 is a perspective view of the safety means that prevent access to the screws;

Figure 6 is a perspective view of the change in position of the elongated plate for varying the adjustment possibilities;

Figure 7 is a perspective view of the actuator with the plate arranged so as to allow a wide angular offset in the open and closed positions; Figure 8 is a plan view of the actuator of Figure 7; and Figure 9 is a diagram of the possibilities of angular offset of the open and closed positions.

Ways of carrying out the Invention

With reference to the figures, the fluid-operated actuator with improved stroke limit adjustment means, generally designated by the reference numeral 1, comprises a containment body 2 which forms internally a chamber 3 in which mutually opposite pistons 4 can slide which act against preloaded springs 5 that produce the return stroke.

The pistons 4 are provided with rack-like portions 6, which engage a pinion formed on the control shaft 10, which is connected to a valve to be driven. Stroke limit means are provided inside the containment body 2 by means of an elongated plate 20, which centrally forms a seat 21 for mating with the control shaft 10.

The elongated plate 20 has, on a first side, end portions 22, which can be engaged by adjustment screws 25 which can be accessed from the outside of the containment body 2, so as to provide the stroke limit, which can be varied by a few degrees and specifically from -5° to +5° with respect to the theoretical zero position, so that it is possible to better connect the fluid- operated actuator to the valve.

In the central portion of the first side, the plate 20 forms a lug 23, which allows open and closed locking by using longer adjustment screws

25, which make it possible to block the rotation of the control shaft, as shown schematically in Figure 4.

In order to ensure locking safety, safety means are provided which consist of a padlock 30, which engages by means of its shackle 31 holes 32 formed in a locking body 33, which can be threaded by inserting in the slot

34 the grooves 35 formed by the adjustment screws.

In this manner, the heads of the screws are covered, preventing the possibility of operating them and consequently maintaining the locked position. The locking body 30 cannot be extracted as long as the shackle 31 of the padlock is inserted in the holes 32.

An important particularity of the invention is the fact that the plate

20, on its second side, which lies opposite the first side, forms a second cam-like profile, which has end portions 24 shaped so as to obtain an offset angle both for opening and for closure, as shown in Figure 9, which is considerably wider than the offset angle shown in the first figure.

In particular, it is possible to obtain an offset from -5° to +15° in the open position and an offset from 75° to 95° in the closed position.

From what has been illustrated above it can be seen that the invention achieves the proposed aim and objects, and in particular the fact is stressed that the particular shape given to the plate 20 makes it possible, by means of a single element, to adapt to all the contingent needs, since the same plate makes it possible, by positioning a first side so that it is directed toward the adjustment screws, to have the usual adjustments of a few degrees for opening and closure as well as the locking position, whereas by reversing the plate, which is connected to the control shaft, it is possible to have a considerably wider angular offset in the open and closed positions, thus allowing better adaptation to all the contingent requirements of application.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2008A002150 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A fluid-operated actuator (1) with improved stroke limit adjustment means, comprising a containment body (2) that forms a sliding chamber (3) of at least one piston (4) for the actuation of a control shaft (10) which can be associated with a valve to be driven, stroke limit means being associated with said control shaft (10), inside said containment body (2), and consisting of an elongated plate (20) that forms, on a first side, a cam-like profile provided with end portions (22) for providing stroke limits that are offset by -5° and +5° with respect to the theoretical open and closed positions of said valve, a central portion (23) being further provided for locking said valve open and closed, characterized in that said plate (20) has, on a second side which is opposite to said first side, a second cam-like profile with end portions (24) that provide stroke limits which are offset by angles that are larger than the offset provided by the end portions of said cam-like profile.

2. The fluid-operated actuator according to claim 1, characterized in that said cam-like profile (24) provides a stroke limit that is offset from -5° to +15° in the open position and from 75° to 95° in the closed position.

3. The fluid-operated actuator according to the preceding claims, characterized in that said elongated plate (20) can be reversed for engaging the adjustment screws (25), connected to said containment body, selectively with said first profile or said second cam-like profile.

4. The fluid-operated actuator according to one or more of the preceding claims, characterized in that it comprises safety means which have a locking body (33) provided with a slot (34) which can be inserted in grooves (35) formed by said adjustment screws (25), a padlock (30) being further provided whose shackle (31) engages in holes (32) formed by said locking body (33) for preventing its sliding disengagement from said adjustment screws (25).

5. The fluid-operated actuator according to one or more of the preceding claims, characterized in that said plate (20) can be mated removably with said control shaft ( 10).