Patent Document

FIELD OF THE INVENTION 
     The present invention pertains to a linear handling unit of the type comprising a fixed body, a movable body that is driven and is alternately movable on the fixed body with the interposition of bearings, at least one linear fluid-type actuator to control the alternate movements of the movable body on the fixed body, and a gripping tool applied to an end interface of the movable body. 
     BACKGROUND OF THE INVENTION 
     Linear handling units of the above-mentioned type have already become known. These units include the type comprising, e.g., as was found in a previous patent of the same applicant, profiled elements which are extruded, light and are easily assembled with the features of being compact, reliable and usable with either a horizontal or a vertical arrangement and combined for setting up units of various configurations and performances. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     The present invention is aimed at providing a novel, original linear movement unit which is improved in terms of the joining of its components, the guiding and sliding of the movable body with respect to the fixed body and positioning and/or correcting and recovering the clearances. 
     The present invention is also aimed at proposing to provide linear recirculating ball bearings having a novel configuration, which can be used not only and advantageously in the linear handling units, but also in other equipment. 
     These objectives of the present invention and evident advantages which derive therefrom are accomplished with a linear handling unit that comprises a fixed body and a movable body which are complementary and superimposed, where one of the bodies carries opposing linear bearings in the front and a motor apparatus, and the other body carries, longitudinally, two lateral studs for guiding and coupling with said linear bearings, and where said studs are in flexible-expandable flanges with an adjusting bar placed therebetween and engaged by means of setscrews to vary the expansion of said flanges and to regulate the clearance between both studs at the same time and the respective bearings. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of the linear unit according to the present invention; 
     FIG. 2 is a plane view of the unit of FIG. 1, from the base of the body considered to be fixed here; 
     FIG. 3 shows a plane view of the unit of FIG. 1, from the base of the body considered to be movable here; 
     FIG. 4 is a side view of the unit of FIG. 1; 
     FIG. 5 is a side view of the unit of FIG. 1, the side opposite the side shown in FIG. 1; 
     FIG. 6 is a longitudinal sectional view of the unit at the level of the actuator apparatus; 
     FIG. 7 is a cross sectional view of the unit according to the arrow VII—VII of FIG. 5; 
     FIG. 8 is a cross sectional view of the unit according to the arrow VIII—VIII, of FIG. 5; 
     FIG. 9 is a cross sectional view according to arrow IX—IX of FIG. 5; 
     FIG. 10 is an exploded view of the components of a linear bearing; 
     FIG. 11 is a perspective view of the assembled linear bearing; and 
     FIG. 12 is a partially sectional perspective view of the bearing of FIG.  11 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in particular, the handling unit shown comprises two complementary, superimposed bodies  11 ,  12 , one fixed and the other alternately sliding on the fixed one. For reference, the body  11  is considered to be fixed here and the body  12  movable, even though the opposite is possible, and the same objects are accomplished at any rate. 
     The two fixed  11  and movable  12  bodies can be obtained from extruded, profiled elements, made of metal, such as aluminum or its alloys and/or advantageously made of a plastic material. 
     The fixed body  11  has a basically U-shaped section with a base  13  and two lateral walls  14 , which are perpendicular to the base, are parallel and delimit between them a channel  15 , in which is arranged the movable body for its linear movements. 
     The fixed body  11  carries, in the base  13 , a motor apparatus for controlling the movable body  12  and on the internal side of each lateral wall  14  a system of linear bearings  16  extending along the fixed body and intended to support and guide the movable body. 
     A longitudinal groove  17  for the mounting of accessories, such as a limit stop  18 , sensors or another device, is provided on the external side of each lateral wall. 
     In the example illustrated, the motor apparatus comprises two fluid-type, parallel pistons  19  which are housed and slide in cylindrical chambers  20  provided symmetrically in the base  13  of the fixed body. The pistons  19  have a dual purpose and have their rods  19 ′ fixed to an interface plate  21  applied to one end of the movable body  12 . For alternate movements of the body  12 , the chambers are fed alternately, from opposite parts of each piston, with a pressurized fluid that is carried there by means of feeding means  22  to be connected to fluid pipes and through holes  23  suitably provided in the base. 
     The linear bearings  16  are arranged and held in seats  24  provided on the internal side of each lateral wall  14  of the fixed body  11 , said bearings being arranged in pairs and being able preferably, but not exclusively, to be ball recirculation bearings and of the type described above. 
     The movable body  12  has a corresponding base  25 , which is placed in a position of at least partial superimposition with the lateral walls  14  of the fixed body  11 , and from which project two parallel flanges  26 , which extend into the channel  15  between said lateral walls  14  or between the linear bearings  16  in the walls. The two parallel flanges  26  are longitudinally separated by a groove  27  having inclined sides  27 ′, which converge in the direction of the free end of the flanges proper. Moreover, each of these flanges is joined to the base  25  of the movable body  12  by means of a tapered part  26 ′ so as to be provided with a relative flexibility. 
     Longitudinally, the external side of each flange  26  has a semicylindrical slot  28 , in which is arranged a cylindrical stud, which rests on the linear bearings  16  contiguous thereto. The studs  29  are made of a suitable material, such as treated steel, and constitute guiding means for the sliding of the movable body  12  on the bearings and in relation to the fixed body  11 . 
     On the bottom of the semicylindrical slot  28  is provided a weakening indentation  30  in order to make the two opposite parts of the flange that delimit the indentation flexible, so that these parts are able to receive and hold the respective stud  29  like pliers. 
     In the groove  27  between the two flexible flanges  26  of the body  12  is inserted an adjusting bar  31  that rests on the inclined sides  26 ′ of the groove proper. The adjusting screws  32 , which rest on the adjusting bar, are screwed from the outside into the base  25  of the body  12  at right angles. The adjusting screws  32  are spaced apart along the bar  31 , and these, screwed down properly, make it possible to support, correct and recover clearances between the studs  29  and the sliding linear bearings  16  when assembling the unit and then at any time as a result of the wear caused by the operation of the coupled parts. By actually acting on the adjusting screws  32 , the adjusting bar  31  interacts with the inclined sides  26 ′ of the flexible flanges  26 , thus expanding same variably in order to adjust, if necessary, the clearances between studs and linear bearings. 
     These bearings (FIGS. 10-12) may be, as stated above, of the ball recirculation type. In a preferred and particularly original embodiment, each bearing  16  consists of two shells  33 , which are complementary, opposite and closed one on the other, a series of balls  34 , and two cylindrical pins  35 . The two shells  33  can be obtained from plastic material molding, therefore without mechanical machining, and treated on the surface (heat-treated) in their parts which are intended to receive the balls  34  and pins  35 . The balls and the pins are made of steel. The two shells, when assembled, form a bearing body having a trapezoidal cross section (FIG. 12) and together delimit an endless track  36  for housing and recirculating the balls  34 . The track  36  has two parallel branches which are connected by semicircular end sections. The branch of the track  36  on the larger part of the base of the bearing body formed by the assembled shells  33  is open towards the outside through a slot  37  and the balls, which pass through that branch from time to time, protrude from the body in order to come into contact with the element to be supported, in the case being discussed with a respective stud  29 . 
     Each shell  33  has a seat  38  for a cylindrical pin  35 . The seats for the pins are open towards the outside of the bearing body through an oblong opening  39  in each sloped side of the trapezoidal section of the body proper. The pins  35  are arranged in a plane at right angles to the plane in which the balls  34  lie, and both are arranged so as to rest on the balls that pass through the branch of the track, which is open towards the outside of the body, and to protrude slightly from the body through the openings  39  corresponding to them. 
     Thus and advantageously, when the bearings are working, their body acts only as a container for balls and pins and is not weighed upon by significant loads. In fact, the loads are then supported by the balls in contact with the element to be supported and to be guided and by the pins which rest, on the one hand, on the balls and, on the other hand, on the walls of the seat in which the bearing is arranged. In other words, the loads acting on the balls are transferred to the pins at right angles and from these to the support walls in the seat for the bearing. 
     Moreover, the trapezoid-shaped bearings can be used in pairs, resting, one on top of another, on a sloped side of the section as shown in FIGS. 7-9, advantageously making adjustments easier for the recovery of the clearances between the bearings and the guided element. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Technology Category: 2