Abstract:
A tool for fitting a belt into the groove of a pulley. The tool comprises a base plate having a first and a second face. The plate is flat or forms a part of a cylinder and the first face is concave. The tool also comprises first and second holding members that are substantially flat and parallel with each other. The holding members are spaced apart and extend from the first face of the base plate. If the base plate is flat, the holding members are perpendicular to the base plate. If the base plate is not flat, the holding members are perpendicular to the axis of the cylinder at least partially formed by the base plate. The tool also comprises a guide member extending from a second face of the plate opposite to the first face.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a tool for fitting a belt into the groove of a pulley. It applies more particularly to power transmission belts and more particularly to the motor vehicle field, to the household electrical goods field and to industry. 
   The Applicant Company markets, in particular as a belt intended for the driving of motor-vehicle accessories (alternator, air conditioning, etc.), a belt that it is possible to fit by stretching and which, after fitting in a transmission system, maintains sufficient tension throughout the lifetime of the belt, without there being any need to tension it by means of a fixed tensioner. 
   The fitting of this belt (of the so-called “snap-on” type) involves high stresses and it is generally carried out using a fitting tool, whether this be in the factory (“first fitting”) or as a replacement. 
   Fitting tools are already known which involve having a part of the tool in contact with the bottom of the groove of the pulley. Such tools are in particular described in the American patents U.S. Pat. No. 3,138,963 (PRINCE), U.S. Pat. No. 4,111,063 (JOURNEY) and U.S. Pat. No. 4,109,544 (CLARK). 
   The disadvantage of these devices is that they are suitable only for belts transmitting low powers, because they come directly into contact with the groove of the pulley which they risk damaging. 
   This risk is even higher for motor vehicle belts (in general of the K type) which have a plurality of serrations to which correspond the complementary profiles of the bottoms of the pulley grooves. 
   Another fitting tool, of the lever type, has been proposed in the patent U.S. Pat. No. 5,653,654 (DAVIS). It comprises two fingers  20  and  21  forming a lever. In order to use it, it is necessary in advance to slacken the tension of the belt, which is not compatible with a belt of the “snap-on” type for which the transmission system is rightly deprived of a tensioner allowing such an operation. 
   Other belt tensioners more particularly intended for belts of this type have been proposed for motor vehicle applications. In particular, reference will be made to the European Patent EP 831 247. This type of tool is applied to the cheek and the edge of the pulley. 
   This has several consequences: 
   on the one hand, the shape of the tool is relatively complicated, 
   on the other hand, the curvature of the tool is defined by the curvature of the pulley, which means that there are necessarily as many patterns of tools as there are diameters of pulleys, 
   and, finally, because of its position, the tool occupies a non-negligible lateral space. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a fitting tool which does not have at least one of the aforementioned disadvantages. 
   The invention thus relates to a tool for fitting a belt into the groove, serrated or not serrated, of a pulley, characterized in that it comprises: 
   a base plate having a first and a second face, which is flat or which forms a part of a cylinder having its concavity facing toward the first face; 
   a first and a second holding member that are substantially flat and that are parallel with each other, which are spaced apart and which extend from a first face of the base plate and perpendicular to the base plate if it is flat, or to the axis of the said cylinder if not flat; and 
   a guide member which extends from a second face of the plate opposite to the first face. 
   According to a first variant, the two holding members are integral with the base plate and spaced apart by a distance corresponding to the standardized width of a pulley. 
   According to another variant, the holding members are mobile in translation with respect to each other in such a way as to vary their distance according to the width of the pulley, a means (locking device, spring return, etc.) being provided for fixing the relative position of the holding members. 
   In particular, a first holding member can be borne by a part that can move in translation with respect to the second holding member which is integral with the base plate. 
   The guide member can be borne by the part that can move in translation. 
   It can also be integral with the base plate, in particular at the level of the second holding member which is fixed. 
   The second holding member can be a folded-down end of the base plate. 
   The tool can be characterized in that the part that can move in translation has a structure with two branches connected to each other by a central section, one of the branches which defines the first holding member having an opening allowing the passage of the base plate and the other branch having a bearing face for the first face of the base plate. 
   In order to allow the adjustment of the distance between the bearing members, the said bearing face can have a finger cooperating with holes formed in the base plate, or a profiled edge cooperating by ratchet effect with serrations formed in the first face of the base plate. 
   The fitting tool can be characterized in that the part that can move in translation has an opening traversed by the base plate and in that it has a return spring of which one end is butted against a bearing plate integral with the base plate and of which the other end bears against the part that can move in translation. 
   The fitting tool can be characterized in that the guide member extends substantially perpendicular to the said second face and has at least one flat region forming an angle with the first holding member, this flat region facing the outside of a perimeter delimited by the base plate and the first and second holding members, and being located at least partly outside of this perimeter. 
   Two of the flat regions can preferably be disposed systematically, at the ends of a central region, which is preferably plumb with the first holding member. 
   The fitting tool can be characterized in that the guide member extends substantially perpendicular to the said second face and has at least one region curved toward the outside of a perimeter delimited by the base plate and the first and second holding members and located at least partly outside of this perimeter. 
   It can have two curved regions disposed, preferably systematically, on either side of a central region, which is preferably plumb with the first holding member. 
   The central region is advantageously flat, and it can extend substantially between two opposite edges of the base plate. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other characteristics and advantages of the invention will appear on reading the following description with reference to the drawings in which: 
       FIG. 1   a  is a perspective view of one embodiment of a fitting tool according to the invention,  FIG. 1   b  illustrating a configuration during the fitting,  FIG. 1   c  being a cross-section of  FIG. 1  taken in the plane of a pulley side. 
       FIGS. 2   a  to  2   d  illustrate the sequence of the fitting of a belt with a fitting tool according to the invention, in this case the one shown in  FIGS. 1   a  and  1   b,    
       FIGS. 3   a  to  3   d  illustrate the distance adjustment between the holding members, in the case of the fitting tool shown in  FIGS. 1   a  and  1   b , and  FIGS. 3   e  and  3   g  illustrate the forces and the torques generated during the fitting. 
       FIGS. 4 to 7 ,  8   a ,  8   b ,  9   a  and  9   b  show variants of a fitting tool according to the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As shown in  FIG. 1   a , a fitting tool denoted by the general reference  1  has a flat base plate  2  of generally rectangular shape which has a bent-down end  3  forming a first holding member. A part  6  provided with a rectangular slot  56  which allows the passage of the base plate  2  can slide longitudinally along the latter. The part  6  has, in cross-section, the general shape of a U, with a central part  61 , bordered on the one hand by a branch  4  forming a second holding member and in which the rectangular slot  56  is formed and, on the other hand, by a branch  62  which has a bearing face  65  for the lower face  22  of the base plate  2  (see also  FIG. 3   a ). This bearing face  65  has in its central section a pin  66  which can be inserted into one of the openings  26  formed along the base plate  2  in order to fix the distance between the holding members  3  and  4 . This distance substantially corresponds to values of width L of a pulley such as the pulley  10  shown in  FIG. 1   a  which the tool  1  straddles. A guide member  5  extends above the upper face  21  of the base plate  2  and forms an extension of the member  4 . 
   This guide member  5  has at least one flat or curved guidance region  51  which is inclined toward the outside of the pulley  10  (in particular by an angle α ( FIG. 3   d ) of less than 30°, for example α=25°) and which is located outside of the perimeter delimited by the members  3  and  4  and the part  29  of the base plate  2  located between the members  3  and  4 . A flat central part  55  extends the member  4  upwards. The function of the guidance region  51  is to direct the belt  30  toward the pulley  10  in order to put it into position, whilst the flat central part  55  guides the belt  30  laterally whilst it is passing over the part  29  of the upper face  21 . A guidance region  52 , symmetrical with the guidance region  51 , can be formed on the other side of the central part  55 , which allows two directions of rotation for the fitting, everything otherwise being the same. 
   The fitting of the belt is described with reference to  FIGS. 2   a  to  2   d.    
   In  FIG. 2   a , the tool is disposed astride the pulley  10  and the belt in the slackened state is placed over the region  29  of the base plate  2  as shown in  FIGS. 1   b  and  2   a , a short section  33  of the belt  30  being already in the groove  11  of the pulley  10  upstream of the fitting tool  1 . Downstream of the fitting tool  1 , the portion  34  is free and laterally overlaps the edge  12  of the pulley  10 . Then, manually or with the help of a tool, the pulley  10  is rotated (in the clockwise direction in  FIG. 2   a ) which has the effect of progressively installing the belt  30  by progressively increasing the length of the portion  33  lodged in the groove  11 . In fact, the guidance region  51  bears on the edge  32  of the belt  30  in the region  34  and guides the belt toward the region  29  of the upper face  21 . 
   By rotation of the pulley  10  (or movement of the tool  1  over its perimeter), the belt is fully installed ( FIG. 2   c ) and the tool can be withdrawn ( FIG. 2   c ). The fitting of the belt is then complete ( FIG. 2   d ). 
   As shown in  FIG. 1   c , the use of a flat base plate  2  means that there are only two straight segments  23  in contact between the lower face  22  of the base plate  2  and the edges  12  and  14  of the pulley  10 . The tool  1  can therefore be used for any diameter of pulley. 
   The belt  30 , because of its passage over the region  29  of the plate  2 , is inserted virtually axially into the groove  11  of the pulley  10 , without rubbing against the edges  12  of the pulley  30 . 
   The adjustment of the distance between the bearing members  3  and  4  is illustrated by  FIGS. 3   a  to  3   d.    
   The fitting of the tool is carried out simply by inserting the free end  21  of the base plate  2  into the slot  56  of the part  6  ( FIG. 3   a ). 
   This play between the slot  56  and the plate  2  makes it possible to unlock the part  6  by rocking which allows the longitudinal displacement of the part  6  ( FIG. 3   b ). By reverse rotation, the part  6  is put into position, the pin  66  being inserted into one of the holes  26  ( FIGS. 3   c  and  3   d ). 
   After putting in position astride the pulley  10  and at the start of the rotation ( FIGS. 3   c  and  3   e ), the lateral force F applied by the edge  32  of the belt during its putting into position induces a rocking torque C b  which allows self-locking of the member  4  against the side  12  of the pulley  10 , which positively locks the assembly. After this locking ( FIG. 3   f ), since the pressure P applied by the belt on the region  29  is low, it is the effect of the counter-torque C r , induced by the force F and by the bearing of the member  3  at B on the side  14  and of the member  3  at A on the side  12 , that allows the tool to be held in equilibrium throughout the entire rotation. The tool then clamps the pulley between the points A and B. After a larger rotation, the belt is already engaged in the groove of the pulley and it is the effect of the supplementary pressure P in the region  29  which keeps the tool in position. At the end of the fitting ( FIG. 3   g ), there is nothing more than this pressure P effect, since the belt no longer applies any lateral force. 
   In the embodiment shown in  FIG. 4 , the distance between the members  3  and  4  is adjusted by means of a ratchet type device ( 68 ,  27 ), a serrated rack  27  being formed for this purpose on the lower face  22  of the base plate  2 , and cooperating with an inclined edge  68  of the branch  62  upon which the base plate  2  bears. 
   The embodiment shown in  FIG. 5  uses a spring which bears at one end of the plate  2  against a folded-down member  72 , and at its other end on the member  4 . Members  71  and  73 , folded down into the axis of the spring allow it to be held in position. In this configuration, the operator separates the part  6  by compressing the spring  77 . Once the fitting tool  1  straddles the pulley, the operator releases his action and the tool remains in position due to the action of the spring  77 . 
   In the embodiments shown in  FIGS. 6 and 7 , the fixing is carried out by means of a screw, either laterally ( FIG. 6 ) or between the faces  21  and  22  of the plate  2  ( FIG. 7 ). 
   In the embodiments shown in  FIGS. 9   a  and  9   b , the plate  2 ′ is cylindrical, with its concavity facing the members  3  and  4  (and therefore facing the pulley  10 ). The members  3  and  4  are perpendicular to the axis of the cylinders. In this configuration, there are two pairs of straight segments  23 ′ and  23 ″ in contact between the lower face  22  and the edges  12  and  14  of the pulley  10  ( FIG. 9   b ), in the case where the curvature of the plate  2  is more pronounced than that of the pulley  10 . 
   In the opposite case, there is only one pair of segments  23  as in the case of  FIG. 1   c . In this case the tool can also be used whatever the diameter of the pulley  10  may be. In any event, the presence of a convex face  21  contributes to a better guiding of the belt  30  in the region  29 . 
     FIGS. 8   a  and  8   b  show a one-piece fitting tool which is suitable for only one width L of pulley but which can be used with pulleys of any diameter. 
   It comprises a base plate  82  having a central plate region  89  delimited on either side by holding members  83  and  84  which extend from the lower face  22 . 
   The central plate  89  (flat or convex in the direction of the members  83  and  84 ) extends laterally by a region of plate  88  of triangular shape ( FIG. 8   b ) which is bordered by a flat guide member  85  which is inclined by an angle α (for example 25°) with respect to the axis of the members  83 ,  84 . The angle α is preferably less than 30°. The member  85  can be curved, with its concavity facing the outside of the tool. 
   Other variant embodiments are possible. Thus the guide member or members can be curved toward the outside (being convex in the direction of the pulley). In the preceding embodiments, the flat central region  55  can be omitted. 
   The tool can be used for fitting any type of belt (in particular a “poly-V” serrated belt of the H, J, K or L type) onto smooth or serrated pulleys. It can also be used with flanged pulleys, with the disadvantage however that the belt will be deformed and taken to a higher tension by the rim of the S-shape associated with the flange.