Pneumatic motor assembly for a lubricant pump

Abstract

A pneumatic motor assembly for a lubricant pump comprises a body which forms a cavity supplied with compressed air, a first hole and a second hole which are formed axially on the side wall of the cavity, a stem, which is slidingly accommodated in the first and second holes and supports, at one end, a piston which moves in a cylinder associated with the body and, at the other end, cooperates with the riser of the pump. An exchanger means is accommodated in the cavity and is provided with an axial through hole which slidingly accommodates a narrow intermediate portion of the stem; a means for diverting the air is associated with a front opening of the cavity and interacts with the exchanger means; and an elastic means cooperates laterally with the exchanger means; the axial through hole includes a wider end portion, which is directed toward the end of the stem that is provided with the piston and accommodates a non-narrow part of the stem during the return stroke of the piston; the elastic means is arranged between the exchanger means and the side wall.

1 . A pneumatic motor assembly for a lubricant pump that comprises a body, which forms a cavity supplied with compressed air, a first hole and a second hole formed axially on the side wall of said cavity, a stem, slidingly accommodated in said holes and supporting, at one end, a piston moving in a cylinder associated with said body and, at the other end, cooperating with the riser of said pump; an exchanger means, accommodated in said cavity and provided with an axial through hole slidingly accommodating a narrow intermediate portion of said stem; a means for diverting said air, associated with a front opening of said cavity and interacting with said exchanger means, and an elastic means which cooperates laterally with said exchanger means, characterized in that said axial through hole comprises a wider end portion, directed toward said end of said stem that is provided with said piston and accommodating a non-narrow part of said stem during the return stroke of said piston; and in that said elastic means are arranged between said exchanger means and said side wall.  
     
     
         2 . The assembly according to  claim 1 , characterized in that said non-narrow part is located directly behind said narrow portion along the return stroke of said piston.  
     
     
         3 . The motor assembly according to one or more of the preceding claims, characterized in that said exchanger means comprises a locator formed by said wider end portion and by said axial through hole, said locator forming an abutment for the corresponding locator formed on said stem astride said narrow portion and said non-narrow part.  
     
     
         4 . The motor assembly according to one or more of the preceding claims, characterized in that said exchanger means comprises an extension toward said riser and in that said narrow intermediate portion comprises an extension equal to said extension of said exchanger means.  
     
     
         5 . The motor assembly according to one or more of the preceding claims, characterized in that it comprises a guiding and sealing bush, screwed into said first hole and protruding moderately into said cylinder so as to not interfere with said return stroke of said piston.  
     
     
         6 . The motor assembly according to one or more of the preceding claims, characterized in that it comprises a guiding and sealing cartridge, rigidly coupled to said second hole and protruding along said stem outside said body toward said riser.  
     
     
         7 . The motor assembly according to one or more of the preceding claims, characterized in that said cartridge comprises a first tubular segment, externally provided with a threaded end part that engages said second complementarily threaded hole and is internally provided with a threaded part.  
     
     
         8 . The motor assembly according to one or more of the preceding claims, characterized in that said cartridge comprises a second tubular segment, internally coaxial to said first segment, and shorter than said first segment, said segment being externally provided with a threaded end part that engages in said complementarily threaded part of said first segment and is internally provided, at said threaded end part, with a hexagonal seat for accommodating a handling tool for screwing said second segment into said first segment, and is provided, on the side of said riser, with an annular gasket for providing a seal on said stem against seepages of air from said cavity to said riser.  
     
     
         9 . The motor assembly according to one or more of the preceding claims, characterized in that said cartridge comprises an inverted U-shaped annular gasket, inserted in said first segment on the side of said riser just below said second segment and preventing seepages of lubricant from said riser into said assembly.  
     
     
         10 . The motor assembly according to one or more of the preceding claims, characterized in that it comprises an annular secondary chamber formed in the bottom of said cylinder.  
     
     
         11 . The motor assembly according to  claim 1 , characterized in that said elastic means comprises a pair of springs.  
     
     
         12 . The motor assembly according to  claim 11 , characterized in that each one of said springs comprises two legs, two arms and a central concavity directed toward said cavity.  
     
     
         13 . The motor assembly according to  claim 12 , characterized in that before assembly said two legs are divaricated and in the active condition said two legs are substantially parallel.  
     
     
         14 . The motor assembly according to  claim 12 , characterized in that before assembly said two legs and said two arms form an obtuse angle and in that in the active condition said two legs and said two arms form a substantially right angle.  
     
     
         15 . The motor assembly according to  claim 12 , characterized in that said legs are inserted in seats formed respectively in said exchanger means and in said body.  
     
     
         16 . The motor assembly according to  claim 15 , characterized in that said seats of said exchanger means comprise two holes and two elastic pins inserted in said pair of holes.  
     
     
         17 . The motor assembly according to  claim 16 , characterized in that said holes in said exchanger means are formed in the central area of a flattened region, in a symmetrical position and at right angles to the longitudinal central axis of said exchanger means.  
     
     
         18 . The motor assembly according to  claim 15 , characterized in that said seats of said body comprise two holes, each divided into a first portion and a second portion, and two elastic pins, inserted in said second portions of said holes.  
     
     
         19 . The motor assembly according to  claim 18 , characterized in that said first portion has a larger diameter than said second portion.  
     
     
         20 . The motor assembly according to  claim 18 , characterized in that said holes in said body are formed in the central band of said body, symmetrically and at right angles with respect to the longitudinal central axis of said body.  
     
     
         21 . The motor assembly according to  claim 19 , characterized in that said first portions of said holes affect said side wall so as to form straight grooves which allow to insert said springs in said pins inserted beforehand in said second portions.  
     
     
         22 . The motor assembly according to one or more of the preceding claims, characterized in that said springs are held in position by two pins inserted in said first portions, said pins being in turn held in position by said diverting means.  
     
     
         23 . The motor assembly according to one or more of the preceding claims, characterized in that said springs are formed by at least one wire shaped so as to lie on a plane.