Abstract:
A guard for gas cylinder actuators, comprising a rigid or deformable covering element, to be fixed to the stem of the gas cylinder actuator with which it is associated or to the translating body against which the gas cylinder actuator is intended to act, the covering element being contoured so as to extend radially from the fixing region in order to protect the stem and the opening of the body of the actuator from which the stem exits.

Description:
[0001]    The present invention relates to a guard for gas cylinder actuators. 
       BACKGROUND OF THE INVENTION 
       [0002]    Generally, gas cylinder actuators are part of equipment for locking a metal sheet adapted to be shaped in a press or worked with another pressing system, for blanking or drawing, and are used to extract or retain the metal sheet during its working. 
         [0003]    Usually, in this type of work and when using these pressing systems, oils or other emulsifying liquids are used abundantly in order to improve work. 
         [0004]    However, while these oils or similar liquids fully perform their task of improving sheet metal working, they often damage the gas cylinder actuators, which are also fitted within the die. 
         [0005]    The oil in fact penetrates the gas cylinder actuators, passing through the gasket, entrained by the moving stem; this condition creates problems in terms of durability of the gas cylinder actuator, since it compromises its tightness with respect to the pressurized gas. 
         [0006]    In order to obviate this drawback, protective domes are known which can be made of various materials, depending on the aggressive agents from which the associated gas cylinder actuator is to be protected, and must be fixed so as to cover part of the body of the gas cylinder actuator on the stem side, which is the part that is most subject to being splashed by the oils and fluids that fall from the overlying metal sheet being worked. 
         [0007]    These domes have a passage hole for the work strokes of the stem, and therefore, although they achieve the task of protecting the body of the gas cylinder actuator, they do not protect sufficiently the gaskets between the body and the stem, since the aggressive liquids penetrate between the hole of a dome and the stem that passes through it and reach the dynamic seals between the body and the stem of the gas cylinder actuator. 
       SUMMARY OF THE INVENTION 
       [0008]    The aim of the present invention is to provide a guard for gas cylinder actuators which is capable of obviating the drawbacks of known types of dome-like device. 
         [0009]    Within this aim, an object of the present invention is to provide a guard which can be applied easily also to existing and working gas cylinder actuators. 
         [0010]    Another object of the present invention is to provide a guard which prevents oils or any other liquid or fluid in general from reaching the dynamic seals provided within the body of a gas cylinder actuator for the stem. 
         [0011]    Another object of the present invention is to provide a guard for gas cylinder actuators which can be manufactured with low costs and with known systems and technologies. 
         [0012]    This aim and these and other objects, which will become better apparent hereinafter, are achieved by a guard for gas cylinder actuators, characterized in that it is constituted by a rigid or deformable covering element, to be fixed to the stem of the gas cylinder actuator with which it is associated or to the translating body against which the gas cylinder actuator is intended to act, said covering element being contoured so as to extend radially from the fixing region in order to protect the stem and the opening of the body of the actuator from which said stem exits. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Further characteristics and advantages of the invention will become better apparent from the following detailed description of six preferred but not exclusive embodiments thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a side view of a gas cylinder actuator with a device according to the invention; 
           [0015]      FIG. 2  is the same side view as in  FIG. 1 , in which the stem of the actuator is extended out of the body of said actuator; 
           [0016]      FIG. 3  is a view of a first embodiment of the means for fixing the covering element to the stem; 
           [0017]      FIG. 4  is a view of a second embodiment of the means for fixing the covering element to the stem; 
           [0018]      FIGS. 5 and 6  are each sectional side views, in two different configurations, of a device according to the invention in a second embodiment thereof; 
           [0019]      FIG. 7  is a sectional side view of a device according to the invention in a third embodiment; 
           [0020]      FIG. 8  is a view of a device according to the invention in a fourth embodiment; 
           [0021]      FIGS. 8   a  and  8   b  each show a variation of a detail of the device in its fourth embodiment; 
           [0022]      FIG. 9  is a partially sectional side view of a device according to the invention in a fifth embodiment thereof; 
           [0023]      FIG. 10  is a partially sectional side view of a device according to the invention in a sixth embodiment thereof. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    With reference to the figures, a guard for gas cylinder actuators according to the invention is generally designated by the reference numeral  10  in its first embodiment. 
         [0025]    The guard  10  comprises a covering element, which is constituted by a dome  11  designed to be keyed by way of fixing means at an end  12   a  of a stem  12  of a gas cylinder actuator  13 . 
         [0026]    The dome  11  is constituted by a tubular body  14 , which is shaped so as to affect a body  15  of the actuator  13  both when the stem  12  is completely extended and when the stem  12  is completely retracted. 
         [0027]    In the embodiment shown, the substantially cylindrical tubular body  14  has, monolithically therewith, an annular cover  17  which surrounds the stem  12 ; therefore, the stem  12  enters a hole  18  of the annular cover  17 ; this embodiment with the body  14  and the cover  17  provided monolithically is, as mentioned, an example, and the tubular body  14  and the annular cover  17  can also be provided as two separate elements which are mutually joined. 
         [0028]    The dome  11  can be made of aluminum, iron, or other metallic materials, but is preferably made of plastic material, particularly polyurethane. 
         [0029]    Such plastic material is transparent or semitransparent, colored or not, so that in any case the entire gas cylinder actuator remains visible to an operator who has to check it when it is in use. 
         [0030]    The dome  11  can also be made of rubber. 
         [0031]      FIG. 3  shows schematically, in a first embodiment, the means for fixing the dome  11  to the stem  12 . 
         [0032]    Such means comprise a snap ring or elastic toroidal ring  19 , which is partially inserted within a corresponding annular slot  20  provided on the end  12   a  of the stem and partly protrudes so as to block the rim of the hole  18  of the annular cover  17 , such rim abutting against a shoulder  21  which is also formed on the stem  12  proximate to the slot  20 . 
         [0033]    The assembly of the actuator and the dome is therefore extremely easy, since it is sufficient to insert the end  12   a  of the stem in the hole  18  of the dome and insert the ring  19  in its seat  20 . 
         [0034]      FIG. 4  is a view of the fixing means in a second embodiment thereof. 
         [0035]    In this second embodiment, the fixing means are constituted by the threaded hole  118  and by a complementary thread  122  provided on the end  112   a  of the stem  112 , onto which the hole  118  is screwed until abutment against the shoulder  121  occurs. 
         [0036]    In another embodiment of the fixing means, which is similar to what will be described hereinafter for a fourth embodiment of the invention and illustrated in  FIG. 8   a , the dome  11  can be keyed to the stem  12  so as to interlock with its hole  18  in an annular slot provided on the stem  12 . 
         [0037]    With the guard according to the invention it has been shown that it is substantially impossible for oil or other emulsified liquid that falls from above the actuator  13  to reach an opening  16  of the body  15  from which the stem  12  exits, proximate to which the seals for the stem are provided in the body  15 . 
         [0038]    As an alternative, the dome  11  can be simply keyed by interference on the end  12   a  of the stem. 
         [0039]    In a second embodiment, shown in  FIGS. 5 and 6  and designated therein by the reference numeral  210 , the guard according to the invention comprises a covering element provided by a telescopic dome  211 . 
         [0040]    The telescopic dome  211  therefore comprises a series of concentric annular parts which can be telescoped with respect to each other, a first base part  211   a  being intended to be fixed to a plane  224  which is jointly connected to the body  215  of the actuator  213 , a last upper part  211   n  being provided with the annular cover  217  to be keyed to the stem  212 . 
         [0041]    In  FIG. 5 , the guard  210  is shown as it appears when the stem  212  is retracted; in  FIG. 6  it is instead shown when the stem is extended. 
         [0042]    The guard  210  with the telescopic dome  211 , by way of the fixing of the annular body  217  and also of the base edge, provided by a perimetric flap  225  of the first annular part  211   a  of the dome  211 , to the plane  224 , prevents the passage of oil or other debris also in the direction from the base of the actuator  213  toward the end of the stem  212 . 
         [0043]    In a third embodiment, shown in  FIG. 7 , the guard  310  comprises a covering element, which is constituted by a concertina hood  311  which is deformable and is provided with a central hole  318  in which the stem  312  of the actuator  313  is inserted and, on the opposite side, the perimetric flap  325  for fixing to the plane  324  which is jointly connected to the body  315  of the actuator  313 . 
         [0044]    In a fourth embodiment, shown in  FIGS. 8 ,  8   a  and  8   b , the device  410  comprises a covering element, which is constituted by a disk  411  to be keyed onto the stem  412  of the actuator  413 . 
         [0045]    The disc  411  has a central hole  418 , by means of which it can be keyed onto the stem  412  in various manners, two of which are described hereinafter. 
         [0046]      FIG. 8   a  shows the disk  411  keyed by interlocking with its hole  418  in an annular slot  430  provided on the stem  412 . 
         [0047]      FIG. 8   b  shows the disk  411  forced onto the stem  412  and in abutment against a shoulder  431  formed on the stem  412 . 
         [0048]    Of course, the disk  411  can also be simply keyed by forcing on the stem  412 . 
         [0049]    In a fifth embodiment thereof, shown schematically in  FIG. 9  and designated therein by the reference numeral  510 , the device  510  comprises a dome  511  which, instead of being keyed so as to surround the stem  512  as in the first embodiment of the device  10  or  110 , is fixed to the upper face  512   b  of such stem by way of one or more threaded elements  532 . 
         [0050]    The cover  517 , which is monolithic with the tubular body  514 , is therefore arranged so as to surmount both the stem  512  and the body  515  of the actuator  513 . 
         [0051]    In a sixth embodiment, shown schematically in  FIG. 10 , the device  610  comprises a covering element, which is constituted by a dome  611  which, instead of being keyed to the stem  612  of the gas actuator cylinder  613 , is fixed to the translating body  623  against which the gas actuator cylinder  613  is designed to act. 
         [0052]    The translating body  623  is for example the movable part, which is arranged upward according to what is shown in  FIG. 10 , of a die or of a press. 
         [0053]    This solution allows to interpose the dome  611  between the opening  616  of the body  615  of the actuator  613 , from which the stem  612  exits, and the translating body  623  from which oil and other undesirable debris usually descend, without resorting to particular machinings of the stem  612  but simply by fixing for example by means of screws  632  the cover  617  of the dome  611  to the translating body  623  or to another body which is rigidly coupled thereto. 
         [0054]    The guard according to the invention must be understood as being providable also in other embodiments which are similar to such sixth embodiment, in which respectively the telescopic dome  211  and the concertina hood  311  are fixed to a corresponding translating body instead of being keyed to the stem of the actuator with which they are associated. 
         [0055]    The guard according to the invention, in addition to protecting against aggressive liquids, is also very useful for sheltering gas cylinder actuators from metal waste and various dirt, which is typical of sheet metal dies and causes damage to the rubber and polyurethane seals of gas cylinder actuators. 
         [0056]    The dome  11 ,  211 ,  511 , the disc  411  and the concertina hood  311  must be understood as being providable in any shape and size to be fitted on gas cylinder actuators of any type. 
         [0057]    In practice it has been found that the invention thus described solves the drawbacks noted in known types of protection for gas cylinder actuators. 
         [0058]    In particular, the present invention provides a guard  10  which can be applied easily also to existing and operating actuators, since it is sufficient to act, if necessary, with simple machinings on the end  12   a  or  112   a  of the stem  12  or  112 , or even just to force the dome, the disk or the hood, depending on the embodiment, for their hole, on such stem of the actuator, without resorting to any machining. 
         [0059]    Further, the present invention provides a guard which prevents oils or any other liquid or fluid in general, but also waste, dust and other machining residues, from reaching the dynamic seals provided within the body of a gas cylinder actuator for the stem, with great advantages for the durability of the actuator. 
         [0060]    Moreover, the present invention provides a guard for gas cylinder actuators which can be manufactured cheaply with known systems and technologies. 
         [0061]    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. 
         [0062]    In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art. 
         [0063]    The disclosures in Italian Patent Application No. PD2007A000226 from which this application claims priority are incorporated herein by reference. 
         [0064]    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.