Abstract:
The second boot that protects parts adjacent to a fixed box from which there projects a rotating hub that is to be connected to a driveline (with the possible presence of a friction clutch or of a torque limiting means) comprises—attached to the fixed box ( 1 )—a disc ( 11 ) with a peripheral edge ( 11 A) for engagement and fastening; and a sleeve ( 17 ) that can be engaged inside the edge ( 11 A- 11 B) of said disc ( 11 ), with fastening clips ( 22 ) capable of being clipped to and unclipped from said edge ( 11 A- 11 B). Said sleeve ( 17 ) may include protective layers around the parts which it encloses.

Description:
FIELD OF THE INVENTION 
     The invention relates to an improved second boot for protecting parts adjacent to a fixed box from which there projects a rotating hub that is to be connected to a driveline incorporating a shaft with universal or other joints and with its own protection, with the possible presence of a friction clutch or of a torque limiting means or other member. Among the objects of the invention, which will be understood on reading the following text, are ease of access for operation on the parts inside, ease of dismantling and so forth. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     The second boot according to the invention basically comprises: attached to the fixed box, a disc with a peripheral edge for engagement and fastening; and a sleeve that can be engaged inside the edge of said disc with fastening clips capable of being clipped to and unclipped from said edge. Said sleeve may include protective layers around the parts which it encloses. 
     In practice, said sleeve may comprise a tubular skirt having flexible portions and made from a relatively flexible synthetic material. 
     Advantageously provided in the disc are ventilation apertures, with deformations that function in conjunction with the passage defined between the sleeve and the protective boot surrounding the universal joint of the driveline; the deformations also tend to limit any deforming of said skirt. 
     On the inside of said tubular skirt there may a tubular layer with insulating properties, and a tubular sheet metal price for reinforcement from the inside of said tubular layer. The tubular layer and said tubular sheet metal piece may both be bent strips held in place by locking rings housed in channels formed in the sheet metal piece. 
     The second boot to which the invention relates may advantageously comprise a connecting chain between said disc and said sleeve and a chain, with a clip, between said disc and the protective sheath of the jointed drive shaft. 
     A cleaner understanding of the invention will be gained from the description and accompanying drawing, which latter shows a practical, non-restrictive example of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 and 2 show the assembly in a side view and partial section with certain components separated in FIG.  1  and assembled in FIG. 2; 
     FIGS. 3,  4  and  5  show certain components in isolation, FIG. 5 being a section of V—V as marked in FIG. 4; 
     FIGS. 6 and 7 correspond to FIGS. 1 and 2 and show an embodiment that has been modified to also include a friction clutch or equivalent torque limiting means; 
     FIG. 8 is a perspective view of the components of a reinforced sleeve; and 
     FIGS. 9 and 10 and  11  show the second boot as mounted, in a partial axial view, in the section on X—X as marked in FIG.  9  and in an enlarged detail of the portion indicated by arrow f 11  in FIG.  10 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As depicted in FIGS. 1 to  5 , the numeral  1  is a general reference for a power take-off box or housing, extending from a portion  1 A of which is a power take-off  3  consisting of a short projecting splined shaft, similar to shaft  3 A which also projects from the box  1 . Engaged on the power take-off  3  in the drawing is the fork  5 A of a universal joint  5 , whose second fork  5 B is combined with a telescopic shaft  7  of a driveline that includes two universal joints, of a type that is known, especially in agricultural machinery, and as such fitted with a protective covering formed by a telescopic sheath  9 A and by a shaft boot  9 B to protect the universal joint  5 . The invention relates to a second or housing boot which is fitted conventionally to portion  1 A of the box  1  to surround the joint  5  and also to overlap around the first boot  9 B of the aforesaid protective covering  9 A,  9 B. 
     As shown in the drawings, a disc  11  with a basically cylindrical edge  11 A terminating in an outward turned-back lip  11 B is attached to the end face of the portion  1 A of the box  1  (the portion from which the power take-off  3  projects). The disc  11  has a series of windows in its flat central area partly for the exit of the power take-off shaft  3 , and partly for its attachment by means of bolts to the end surface of the portion  1 A, adapting it to the different dimensions of commercially available boxes; furthermore, and characteristically, said disc  11  has ventilation apertures  13  which are made by slitting the sheet metal of the disc  11  and bending the material of said disc into deformations  13 A. These deformations  13 A project from the surface around and immediately inside the edge  11 A of the disc. The disc  11  is attached to the end surface of the portion  1 A with bolts  15  so that it can easily be attached and made substantially secure while yet being easily removable. 
     A sleeve  17  can be fastened to the disc  11  and constitutes the main structure of the second boot. This sleeve  17  comprises a skirt  19  which is at least partly flexible with corrugations  19  and which forms a shaped edge  20  to allow it to be inserted inside the edge  11 A and rest against the lip  11 B of the disc  11 . The sleeve  17  is fitted with clips  22  for clipping it to said terminal peripheral lip  11 B of the edge  11 A of the disc  11 , in such a way that it can be released at any time by a quick and very simple operation. A light chain  24  can be attached to the disc  11  and to the sleeve  17  so that the sleeve cannot be lost, but also allows said sleeve  17  to be partially removed with ease from the disc  1  fixed to the box  1 .  26  denotes another chain (see FIG. 2 in particular) that can in a quickly detachable way connect the protective covering  9 A,  9 B of the universal-jointed shaft  7 ,  5  to the second boot which is represented by the disc  11  and sleeve  17 , and actually to connect said protective covering to the disc  11 , in order to prevent spontaneous rotation of said protective covering  9 A,  9 B. 
     The second boot formed by the disc  11  and sleeve  17  is adapted for axial length by removing some of the corrugated part  19 , in order to adapt the second boot to the dimensions of the shaft to which it is to be fitted. 
     The second boot constructed as described may be sufficient to protect the members of the driveline to which it is fitted. In certain cases, however, the second boot requires reinforcing and must also be made protective from the standpoint of thermal insulation, when a member such as a friction clutch or a torque-limiting coupling or the like is present as indicated at  28  in FIGS. 6 and 7. In these cases it is useful to have a reinforced second boot to offer greater strength than the skirt  19 . In this case (FIGS. 6 to  10 ) the sleeve  17  is given insulating layers and reinforcing layers. In particular, the sleeve  17  may be given a layer  30  of thermal insulation for protection against heating of the member present in the driveline, such as the clutch  28  or other equivalent member. A layer of sheet metal  32  is used to hold the layer  30  in place, both these layers being in the form of open rings and the sheet metal piece  32  being applied on the inside of the layer  30 , which in turn is applied to the inside of the smooth part  19 B of the sleeve  17 , which smooth part adjoins both the corrugated part  19 A and the edge  20 . In order to keep the two layers  30  and  32  in the correct position as shown in FIG.  10  and in FIGS. 6 and 7 and in the detail shown in FIG. 11, the sheet metal piece  32  comprises two grooves  32 A around its annular edges to house two locking rings  34  which are elastically expandable and so hold the assembled layers  30  and  32  between the corrugated part  19 A and the shaped edge  20  designed to be coupled to the disc  11 . The layers  30  and  32  give greater strength and greater protection not only to mechanical stresses but also to the effects of heat transmission. 
     It will be clear that once the second boot has been mounted, it will be a simple matter to release the clips  22  to withdraw the sleeve  17  of the second boot from the disc  11  in order to gain access to the components normally contained inside and protected by the second boot when the latter is attached to the disc  11 . Releasing and reattaching the sleeve  17  in done with great ease by operating the clips  22 . 
     It will be understood that the drawing shows only an illustrative embodiment purely by way of a practical demonstration of the invention, it being possible for the invention to be varied as regards shapes and arrangements without thereby departing from the scope of the concept on which it is based. Any reference numerals which may appear in the accompanying claims are for the purpose of facilitating the reading of the claims with reference to the description and drawing, and do not limit the scope of protection represented by the claims.