Abstract:
A device to protect apparatus has a movable section moved alternately by drive means housed in a fixed casing of said apparatus, this alternating motion relative to the fixed casing creating an opening that expands and contracts in a lengthwise direction. The protection device comprises: a plurality of protection elements each having at least one covering portion designed to transversally close said opening and extending lengthwise; means for fixing one end of the protection device to the apparatus; and means for fixing the opposite end of the protection device to the movable part of the apparatus, retaining means also being envisaged for connecting adjacent protection elements to one another and designed to allow the plurality of protection elements to telescopically extend and retract so as to close off said opening lengthwise as the opening expands and contracts.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a device for the protection of moving machine parts. 
     In a machine tool or other manufacturing machine, the moving parts, especially the drive parts, are generally required to be protected by a suitable device or movable appliance, which, following the movements of the machine, keeps the moving parts shut off from the outside environment in order to prevent accidents to personnel working on or near the machine, to prevent dirt or other objects from coming into contact with the moving parts, thus reducing machine efficiency, and to prevent damage due to splashing of lubricant or other material. 
     Various different types of protective devices are known. These include devices designed to cover an opening in a casing which houses moving machine parts, this opening expanding and contracting at least in a lengthwise direction while the machine is working. These devices comprise a set of flat covering plates which protect the working parts of the machine located in the housing. 
     In these known protection devices, the covering plates as a whole are able to move between an extended position in which the plates are lined up lengthwise and completely close the opening, thus covering the working parts of the machine, and a retracted position in which the plates are gathered up over one another. 
     To enable the linear extension and retraction movements of the plurality of covering plates, protection devices of this kind have separate lateral mounting blocks with grooves in them. The lengthwise edges of each plate are inserted into the corresponding grooves so that the plates can slide backwards and forwards in separate parallel planes. 
     The main drawbacks of a protection device of this kind, used for closing flat openings, stem from the large number of parts which it consists of. This is in itself a major disadvantage but is closely connected to another major disadvantage due to the fact that, to close an opening of variable size on working apparatus, a suitable number of mounting blocks must be fitted beforehand on the sides of the opening in a plane above that in which the opening itself lies. The resulting structure can be extremely bulky and, indeed, a protection device of this kind cannot be applied to working apparatus at all unless sufficient room is provided to accommodate these cumbersome, lateral mounting blocks. 
     Another serious disadvantage is that chips and swarf from machining operations tend to settle in the the grooves in the mounting blocks, causing the protection plates to jam and, in the long run, making the protection device unusable. 
     The present invention has for an object to overcome the above mentioned drawbacks. 
     SUMMARY OF THE INVENTION 
     This object is achieved by providing a protection device, especially for apparatus with a moving part driven alternately by drive means housed in a fixed casing, so as to form an opening that, during operation, expands and contracts lengthwise relative to the fixed housing as a result of the alternate movements; said protection device being characterized in that it comprises: a plurality of protection elements each having at least one covering portion designed to transversally close said opening and extending lengthwise; means for attaching one end of the plurality of protection elements to the fixed part of the housing; and means for attaching the opposite end of the plurality of protection elements to the movable part of the apparatus; the protection device further comprising retaining means for connecting adjacent protection elements to one another and designed to allow the plurality of protection elements to telescopically extend and retract so as to close off said opening lengthwise as the opening expands and contracts. 
     A protection device made in this way, that extends and retracts telescopically, does not require additional lateral mounting blocks and therefore has a much simpler structure than previously known devices. Another advantage is that it can be mounted inside the opening in the fixed housing, which means that it can be used in confined spaces on apparatus to which the known devices of the kind describe above cannot be applied. 
     Another advantage of the protection device disclosed herein is that it does not jam on account of chips and swarf as is the case with known devices. 
     The present invention also relates to an apparatus and a vise that mount the present protection device, respectively. 
     The dependent claims refer to specific, advantageous embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the invention are apparent from the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention and in which: 
     FIG. 1 is a perspective view of the vise that mounts the preferred embodiment of the present protection device, shown in the retracted position; 
     FIG. 2 is a perspective view of the vise that mounts the preferred embodiment of the present protection device, shown in the extended position; 
     FIG. 3 is a side view, with parts in cross section, of the preferred embodiment of the present protection device, shown in the extended position; 
     FIG. 4 is a front perspective view of the preferred embodiment of the present protection device, shown in the extended position; 
     FIG. 5 is a top view of the preferred embodiment of the present protection device, shown in the extended position; 
     FIG. 6 is a bottom view of the preferred embodiment of the present protection device, shown in the extended position; 
     FIG. 7 is an exploded view of a pair of adjacent protection elements of the preferred embodiment of the present protection device; 
     FIG. 8 is a view of FIG. 3 in cross section through line  8 - 8 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show an apparatus  10 , namely a vise, comprising a fixed body or casing  12  which houses a longitudinal lead screw  14  that drives a movable block  16  in a straight line towards a second, fixed block  18  attached to the casing  12 , the blocks having holes  20  and  22  in them so that screws can be inserted into them in order to mount corresponding jaws (not illustrated) used to securely hold parts to be worked. 
     The vise illustrated here also envisages a tubular element  24  attached to the casing  12 , protruding from one end of it and coaxially mounting, in such a way that it can freely rotate, an external extension  26  of the lead screw designed to be driven by the output shaft of a motor or by equivalent drive means. 
     As it moves along in a straight line, the jaw mounting block  16  creates an opening behind it which expands and contracts in a lengthwise direction during work and which is covered over by the protection device  28  made according to a preferred embodiment of the present invention. In FIG. 1, the protection device  28  is shown in a gathered up or retracted condition where almost all of it protrudes from the casing  12 , while in FIG. 2, it is shown in an extended condition where it completely covers the variable size opening. 
     These two figures, in particular FIG. 1, show that the extensible protection device slides, if necessary guided as it extends and retracts, between the top edges of two opposite longitudinal walls  27 ,  29  of the casing which houses the lead screw. 
     Also, the top part of the casing  12  is preferably open at the end where the protection device is attached to the fixed part of it so that the protection device can protrude from it and, when gathered up in the retracted position, can be supported on the outside of it. 
     FIG. 2 in particular shows that the protection device  28  is made up of a plurality of protection elements consisting, in this preferred embodiment, of a first end protection element  30  attachable to the movable jaw mounting block  16  and a set of intermediate protection elements, labelled  32 ,  34 ,  36  and  38  located between the first end protection element  30  and a supporting end element  40  which can be attached to the fixed part of the apparatus, in this case, to the protruding tubular element  24 , as described in more detail below. 
     With reference also to FIGS. from  3  to  8 , it can be seen that each protection element in turn comprises a covering portion, labelled  30   c ,  32   c ,  34   c ,  36   c ,  38   c  wide enough to tranversally cover the opening and extending for a certain length. 
     In the preferred embodiment illustrated here, to enable the covering device to move between the sidewalls  27  and  29  of the casing, there are retaining means for connecting adjacent or consecutive protection elements to one another and allowing the plurality of protection elements to telescopically extend and retract by holding one protection element to the adjacent or consecutive element while at the same time letting them slide over one another. 
     With reference to FIGS. 6 and 7 in particular, the retaining means of each protection element comprise a first and a second longitudinal sliding element, labelled  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b ,  38   a ,  38   b , consisting of flexible rectangular sliding and retaining strips positioned under the corresponding covering portions  30   c ,  32   c ,  34   c ,  36   c ,  38   c  and pressing the adjacent protection element against the underside of the covering portion of each protection element. 
     Said first and second longitudinal sliding and retaining strips protrude from the opposite longitudinal edges of the corresponding covering portions in such a way that the first and second strips of all the protection elements are longitudinally aligned and so that the inner or upper surface of each strip slides against the outer or lower surface of the longitudinal strip of the next protection element, as clearly shown in FIG.  3 . 
     In the preferred embodiment described here, there is a pair of longitudinal sliding and retaining strips for each protection element to connect all the protection elements to one sliding and another. However, each protection element might instead have only one retaining strip or more than two sliding and retaining strips. 
     The retaining strips  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b ,  38   a ,  38   b  of each protection element protrude from the latter in a lengthwise direction and are fixed at one end to the corresponding covering portion  30   c ,  32   c ,  34   c ,  36   c ,  38   c  thanks to substantially perpendicular fixing portions, labelled  30   d ,  32   d ,  34   d ,  36   d  and  38   d  in FIG.  6 . Hence, it is possible to obtain covering portions whose width may be completely independent of the shape of the corresponding retaining means and which may, as in this case, be constant for all the covering portions, so as to form a protection device which spans the full width of the opening between the walls  27  and  29  along the entire length of the opening. 
     The above mentioned fixing portions  30   d ,  32   d ,  34   d ,  36   d  and  38   d  also have the effect of transversally stiffening the covering portions. 
     The perpendicular fixing portions  30   d ,  32   d ,  34   d ,  36   d  and  38   d  are long enough to enable them to be inserted between the retaining means  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b ,  38   a ,  38   b  and the covering portions  30   c ,  32   c ,  34   c ,  36   c ,  38   c  of the adjacent or consecutive elements  32 ,  34 ,  36 ,  38 ,  40 . 
     The perpendicular fixing portions  30   d ,  32   d ,  34   d ,  36   d  and  38   d  consist of an edge of the flat covering portion folded down at right angles at one end of the protection element in such a way as to form a surface against which each protection element  30 ,  32 ,  34 ,  36 ,  38  stops against each adjacent or consecutive protection element  32 ,  34 ,  36 ,  38 ,  40  when they slide over each other to reach the retracted position. 
     With reference in particular to FIGS. 3,  6 ,  7  and  8 , it can be seen that to guide each protection element  30 ,  32 ,  34 ,  36 ,  38  during extension and retraction, the protection elements  32 ,  34 ,  36 ,  38  are equipped with first and second guide elements labelled  32   e ,  32   e ,  34   e ,  34   e ,  36   e ,  36   e ,  38   e ,  38   e  acting sideways in opposite directions on the longitudinal sliding and retaining strips of the preceding protection element, that is to say, on the strips  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b.    
     Said first strips  30   a ,  32   a ,  34   a ,  36   a ,  38   a  and second strips  30   b ,  32   b ,  34   b ,  36   b ,  38   b  of the protection elements are aligned lengthwise in such a way that the strips of any two adjacent protection elements are laterally offset from each other and so that the side guide elements  32   e ,  32   e  and  36   e ,  36   e  can act on the longitudinal edges of the retaining strips  30   a ,  30   b ,  34   a ,  34   b  of the preceding element which are bent transversally towards the outside of the protection devic e , while the side guide elements  34   e ,  34   e ,  38   e ,  38   e  act on the longitudinal edges of the retaining strips  32   a ,  32   b ,  36   a ,  36   b  of the preceding element which are bent transversally towards the inside of the protection device. 
     To guide the retaining strips  38   a  and  38   b  of the protection element  38 , the end support element  40  is equipped with similar guide elements  40   e ,  40   e  which act on the longitudinal edges bent transversely towards the inside of the retaining strips  38   a  and  38   b  of the preceding element. 
     As illustrated, the side guide elements  32   e ,  32   e ,  34   e ,  34   e ,  36   e ,  36   e ,  38   e ,  38   e ,  40   e ,  40   e  protrude perpendicularly from the strips of the corresponding protection elements and consist of short longitudinal portions. 
     As clearly shown in FIGS. 6 and 7, means are also envisaged for stopping the extension of the protection elements when the protection device is in the extended position, said means comprising, on each protection element, transverse portions or teeth  30   f ,  30   f ,  32   f ,  32   f ,  34   f ,  34   f ,  36   f ,  36   f ,  38   f ,  38   f  which protrude from the free end of the corresponding retaining strips  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b ,  38   a ,  38   b , said teeth coming into contact with an opposing stop part made on the transverse vertical edge of corresponding side guide elements  32   e ,  34   e ,  36   e ,  38   e ,  40   e . Only the edges  32   g ,  32 g and  34   g ,  34   g  are shown in FIG. 7 by way of example. 
     There are also perpendicular retaining and guide means acting on each longitudinal sliding strip to keep it in contact with the strip of the adjacent protection element. Said perpendicular retaining and guide means acting on each longitudinal sliding and retaining strip  32 ,  34 ,  36 ,  38  and on the end support element  40 , comprise for each longitudinal sliding strip  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b ,  38   a ,  38   b  a corresponding element  32   i ,  32   i ,  34   i ,  34   i ,  36   i ,  36   i ,  38   i ,  38   i ,  40   i ,  40   i , extending transversally from the free end of a perpendicular side guide element  32   e ,  32   e ,  34   e ,  34   e ,  36   e ,  36   e ,  38   e ,  38   e ,  40   e ,  40   e  and designed to slide on the underside of the corresponding longitudinal strip  30   a ,  30   b ,  32   a ,  32   b ,  34   a ,  34   b ,  36   a ,  36   b ,  38   a ,  38   b.    
     As shown in FIGS. 3,  4  and  6 , the end element  40  of the protection device is attached to the fixed part  24  of the apparatus by attachment means comprising opposing jaws  42 ,  44  extending downwards from the end support element  40  and yielding elastically in such a way that they can be inserted into the fixed part  24 , their inner profile being arc-shaped to adapt to the circular shape of the fixed part  24 . 
     In particular, these opposing gripper jaws  42  and  44  are mounted on the end support element  40  by a flat portion  45  (shown in FIGS. 3 and 4) extending substantially perpendicular close to the rear end of the end element  40  so that when the plurality of protection elements are in the retracted position, they are supported on the outside of the aforementioned opening, as clearly shown in FIG. 1, thanks to the longitudinal side elements  40   a ,  40   b  in which the strips  38   a  and  38   b  of the preceding protection element  38  are slidably supported. 
     In particular, as shown in FIG. 3, said flat portion  45  is substantially perpendicular but inclined slightly towards the front of the protection device in such a way as to exert an opposing force which keeps the protection device, when fitted, substantially within the area bounded by the sidewalls of the apparatus. 
     As clearly shown in FIG. 6, the end support element  40  also has a flat portion  47  having, on the side facing the preceding protection element  38 , a stop edge  40   d  which comes into contact with the portion  38   d  of the preceding protection element  38 . 
     Appropriate means are also envisaged for attaching the first end protection element to the movable part of the apparatus. They comprise (see FIGS. 3 and 6) a pair of hook-like elements  46  which are inserted into corresponding slots made in a flat portion  48  that is integral with the movable mounting block  16 . 
     The drawings also show clearly that each protection element  30   c ,  32   c ,  34   c ,  36   c ,  38   c  consists of a small flat plate, substantially quadrilateral in shape and having a transversal edge  30   h ,  32   h ,  34   h ,  36   h ,  38   h  slightly inclined or curved downwards so as to make good contact with the top surface of the corresponding covering portion  32   c ,  34   c ,  36   c ,  38   c  of the adjacent protection element or with the flat portion  47  of the support element  40  in order to create a hermetic seal between the covering portions. 
     Each protection element in the present protection device is preferably made from metal plate suitably formed by shearing and bending. However, other materials, such as, for example, a suitable plastic, and any other forming process could be effectively used for the present invention. 
     The invention described can be subject to modifications and variations without thereby departing from the scope of the inventive concept Moreover, all the details of the invention may be substituted by technically equivalent elements.