Patent Publication Number: US-6216330-B1

Title: Method of sleeving an at least locally cylindrical part into a tubular part in a cruciform arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of copending application Ser. No. 08/781,817, filed Jan. 10, 1997U.S. Pat. No. 5,882,139 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is generally concerned with sleeving an at least locally cylindrical part into a tubular part in a cruciform arrangement, i.e. sleeving the cylindrical part into the tubular part in a direction that is globally transverse to the lengthwise direction of the latter. 
     In the present context the expression “at least locally cylindrical” is to be understood as referring to a part having an exterior surface which is, at least locally, where it is sleeved into the tubular part, a cylindrical surface, i.e. a surface which has parallel generatrices regardless of the nature, circular or otherwise, of the contour of its cross-section. 
     This at least locally cylindrical part, which will be referred to hereinafter for convenience as the cylindrical part, may be solid, hollow or tubular. 
     In the case of a hollow or tubular part, it may accommodate at least one other component of any kind. 
     2. Description of the Prior Art 
     The assemblies formed of a cylindrical part of this kind sleeved into a tubular part find applications in assembling the parts together, for example in the manufacture of automobiles. 
     A hole is made through the tubular part adapted to envelope the overall contour of the cylindrical part and, for example in a press, the cylindrical part and the tubular part are conjointly caused to move relative to each other so that the cylindrical part is forcibly inserted into the hole in the tubular part from one side of the latter while the tubular part is braced externally on the opposite side. 
     Because of its tubular structure, the tubular part has two walls around the hole. 
     During the sleeving of the cylindrical part, the wall on the side from which the cylindrical part is inserted is the first to be subjected to the sleeving force and in practice it may be deformed to some degree because of this. 
     As a result of this, the cross-section of the tubular part around its hole is modified, at least locally, which may compromise the quality of the mechanical connection normally obtained between the cylindrical part and the tubular part and, in any event, the visible deformation of the tubular part can only cast doubt on this quality. 
     It is therefore usually necessary to discard the assembly formed in this way if the tubular part that it includes shows any signs of such deformation. 
     A general object of the present invention is an arrangement that has the advantage of preventing such deformation. 
     SUMMARY OF THE INVENTION 
     To be more precise, in a first aspect, the present invention consists in a method of forcibly sleeving an at least locally cylindrical part into a tubular part globally transversely to the latter, wherein, a hole enveloping the overall contour of said cylindrical part passing through said tubular part, said cylindrical part and said tubular part are conjointly caused to move relative to each other so that said cylindrical part is forcibly inserted in said hole in said tubular part from one side of the latter whilst said tubular part is braced externally on the opposite side, in which method, before insertion of said cylindrical part into said hole in said tubular part, a spacer is inserted into said tubular part through said hole and is adapted to brace it internally near said hole, along at least a portion of the perimeter thereof, said spacer inserted in said tubular part in this way remaining therein afterwards. 
     This spacer may be inserted into the tubular part from either end. 
     However, apart from the fact that, for completeness, this would require time-consuming and complex work at both ends of the tubular part, it is impossible if the tubular part is an elongate part, for example, i.e. a part that is sufficiently long for the hole into which the cylindrical part must be inserted to be too far away from either end for it to be reached from either end. 
     The method of the invention therefore inserts the spacer into the tubular part through the hole into which the cylindrical part must be inserted. 
     In practice, in the method in accordance with the invention, to achieve this the spacer is first inserted axially in the hole in the tubular part and is then radially expanded between the two walls of the tubular around the hole. 
     Be this as it may, because of the presence of the spacer within the tubular part before the cylindrical part is inserted into its hole, the wall of the tubular part that is on the side from which the cylindrical part is inserted is advantageously braced internally, which is very effective in preventing any deformation of it. 
     In other aspects, the present invention also consists in a tool for inserting a spacer of this kind and any assembly of two parts sleeved together in a cruciform arrangement, i.e. a cylindrical part and a tubular part having a transverse hole into which the cylindrical part is forcibly inserted, which includes, between the two walls of the tubular part around the hole, a spacer that extends around at least a portion of the perimeter of said hole. 
     The objects of the invention, their features and their advantages will emerge from the following description given by way of example with reference to the accompanying diagrammatic drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an assembly formed of two parts sleeved together in a cruciform arrangement by a method in accordance with the invention. 
     FIG. 2 is a view of this assembly to a larger scale and in longitudinal section on the line II—II in FIG.  1 . 
     FIG. 3 is a perspective view of the spacer used in accordance with the invention, shown in its initial state. 
     FIG. 4 is a plan view of the spacer, as seen in the direction of the arrow IV in FIG.  3 . 
     FIGS. 5 and 6 are respectively views in axial section on the lines V—V; and VI—VI in FIG. 4 
     FIGS. 7A,  7 B,  7 C and  7 D are partial views in longitudinal section, similar to that of FIG. 2, showing to a different scale various successive stages in the fitting of the spacer of the invention between the two walls of the tubular part into which it must be inserted. 
     FIG. 8 is a plan view of part of the tubular part equipped with the spacer, as seen in the direction of the arrow VIII in FIG.  7 D. 
     FIG. 9 is a partial view in longitudinal section, similar to those of FIGS. 7A,  7 B,  7 C and  7 D, showing the forcible insertion of the cylindrical part into the hole in the tubular part. 
     FIG. 10 is a plan view similar to that of FIG. 4, showing a different embodiment of the spacer of the invention. 
     FIG. 11 is a plan view of a further embodiment of the spacer. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in the figures, the overall aim is to produce an assembly  10  which, as seen most clearly in FIG. 1, is formed of two parts sleeved together in a cruciform arrangement, namely a cylindrical part  11  and a tubular part  12 . 
     As explained hereinabove, the cylindrical part  11  is generally defined as a part the exterior surface  13  of which is a cylindrical surface, at least locally, where it is sleeved into the tubular part  12 . 
     In the embodiment shown, the cross-section of this exterior surface  13  is circular and continuous. 
     It could equally well have some other contour, however, and/or be discontinuous to a greater or lesser degree. 
     In the embodiment shown the cylindrical part  11  is solid, in the manner of a rod. 
     However, it could equally well be a hollow part, for example a tubular part, like the tubular part  12 . 
     This is why its outline is marked with crossed lines, in the conventional way, in FIGS. 2 and 9. 
     If the cylindrical part  11  is a tubular part with a circular cross-section, it can provide a hub for a shaft of any kind or house a hub of this kind. 
     In the embodiment shown, the tubular part  12  is an elongate part, for example. 
     In other words, in this embodiment, it is a part which is elongate in a lengthwise direction D shown in chain-dotted line in FIGS. 1,  2  and  8  and is also thin. 
     Its cross-section and its thickness can be uniform or vary. 
     In the embodiment shown the tubular part  12  is rectilinear or substantially rectilinear. 
     This is not necessarily so, however. 
     To the contrary, this tubular part  12  can also be curved or bent to a greater or lesser extent. 
     The tubular part  12  has, globally transversely to it, more specifically to its lengthwise direction D, a hole  14  for the cylindrical part  11 , passing completely through it, enveloping the overall contour of the cylindrical part  11  and into which the cylindrical part  11  is forcibly inserted. 
     In the embodiment shown, the hole  14  is at a distance from both ends of the tubular part  12 . 
     This is not necessarily so, however. 
     In the embodiment shown, the tubular part  12  forms a bar the cross-section of which, uniform over all of its length, is globally flattened like a buttonhole, substantially perpendicular to the generatrices of the cylindrical part  11 . 
     This is not necessarily so either, however. 
     To the contrary, the cross-section of the tubular part  12  can be of any kind and/or vary along its length. 
     It is sufficient for it to have a width L perpendicular to the generatrices of the cylindrical part  11  sufficient to receive the cylindrical part  11 . 
     Be this as it may, the tubular part  12  has two walls  15  around the hole  14 . 
     In the embodiment shown, and given what has been stated above, these two walls  15  are substantially plane and parallel to each other, at least near the hole  14 . 
     However, this is not necessarily so. 
     In the embodiment shown, the walls are also substantially perpendicular to the generatrices of the cylindrical part  11 . 
     This is not necessarily so either, however. 
     In a manner that is known in itself, for sleeving the cylindrical part  11  into the tubular part  12 , as shown in FIG. 9, the cylindrical part  11  and the tubular part  12  are conjointly caused to move relative to each other so that the cylindrical part  11  is forcibly inserted into the hole  14  in the tubular part  12 , from one side of the latter, in the direction of the arrow F 1  in FIG. 9, with the tubular part  12  braced externally on the opposite side. 
     In practice this operation is carried out on a press. 
     As shown in FIG. 9, the tubular part  12  then rests on the table  17  of the press, appropriately attached to the latter with the hole  14  vertically aligned with a complementary opening  18  in the table  17 , and the cylindrical part  11  is attached to the piston, not shown, of the press. 
     In accordance with the invention, a spacer  20  is inserted into the tubular part  12  before the cylindrical part  11  is inserted into the hole  14  in the latter, to brace it internally near the hole  14  along at least a portion of the perimeter of the hole; accordingly, the spacer is matched to the shape and/or the cross-section of the profile of the tubular part  12  near the hole  14 , so that the spacer  20  when fitted into the tubular part  12  is then retained permanently in the latter. 
     As shown here, the spacer  20  is preferably formed by at least two annular segments  21 , so that it can expand radially, for reasons explained below. 
     In the embodiment shown more particularly in FIGS. 1 through 9, there are only two segments  21  and, the spacer  20  being globally annular, each subtends an angle of substantially 180°. 
     Furthermore, in this embodiment, as shown in FIGS. 3 through 6, the segments  21  are initially attached to each other in the circumferential direction in a separable manner. 
     To this end, the spacer  20  in practice includes, at the ends of a diameter, two areas  22  of reduced strength produced by two grooves  23  which run its full height on its inside edge. 
     The outside edge  25  of the spacer  20 , to be more precise that of each of its segments  21 , preferably has an overall contour in plan view similar to that of the hole  14  in the tubular part  12 . 
     In the embodiment shown, the external edge  25  of the spacer  20  therefore has a circular contour the same diameter as the hole  14  in the tubular part  12 . 
     Likewise, the spacer  20  has an inside edge  26 , to be more precise that of each of its segments  21 , with an overall contour in plan view similar to that of the hole  14  in the tubular part  12 . 
     In the embodiment shown, the inside edge  26  of the spacer  20  therefore also has a circular contour with the same radius as the hole  14  in the tubular part  12 . 
     Finally, the spacer  20  is preferably adapted to be wedged between the two walls  15  of the tubular part  12  around the hole  14 . 
     As shown here, for example, the spacer  20 , to be more precise each of its segments  21 , has an insertion bevel  27  at its external edge on at least one face, in practice on both faces. 
     In the embodiment shown, the insertion bevel  27  has a crescent-shape contour in plan view (see FIGS.  3  and  4 ). 
     Be this as it may, the insertion bevels  27  of the same segment  21  on the opposite faces of the spacer  20  converge in the direction from the inside of the spacer  20  to its outside. 
     The thickness E 1  of the spacer  20  from one of its faces to the other, ignoring the insertion bevels  27 , (see FIGS. 5 and 7A) is substantially equal to the distance E 2  between the insides of the two walls  15  of the tubular part  12  around the hole  14  when unstressed, being in practice slightly greater than this distance E 2  (see FIG.  7 A). 
     In the embodiment shown, the spacer  20 , to be more precise each of the segments  21  of the latter, also has a bevel  28  on its inside edge on at least one face, in practice both faces. 
     The bevel  28  is very much smaller in the radial direction than the insertion bevels  27 . 
     The bevels  28  of the same segment  21  on the opposite faces of the spacer  20  converge in the direction from the outside of the spacer  20  to its inside. 
     In the embodiment shown, and for reasons that emerge hereinafter, the inside edge  26  of the spacer  20 , to be more precise that of each of its segments  21 , has a concave profile in axial section. 
     As shown here, for example, the axial section of this inside edge  26  is circular. 
     The spacer  20  utilized in accordance with the invention is made from a hard synthetic material resistant to compression, for example. 
     In the embodiments shown, it has a plane of symmetry perpendicular to its axis, i.e. perpendicular to the axis of the ring that it forms. 
     In accordance with the invention, this spacer  20  is inserted into the tubular part  12  through the hole  14  in the latter. 
     In more detail, for insertion of the spacer  20  into the tubular part  12 , by the method in accordance with the invention, the spacer  20  is first inserted axially into the hole  14  in the tubular part  12 , in the direction of the arrow F 2  in FIG. 7A, and is then expanded radially between the two walls  15  of the tubular part  12  around the hole  14 , in the direction of the oppositely directed arrow F 3  An FIG.  7 C. 
     It may be inserted using a tool  30  of the type shown diagrammatically in FIGS. 7A,  7 B,  7 C and  7 D, for example. 
     The tool  30 , which operates in the manner of a manipulator, includes a support  31 , for example in the form of a box section open at the bottom, at least two jaws  32  mobile radially on the support  31  between a close together position in which, as shown in FIGS. 7A and 7B, they are adapted conjointly to receive the inside edge  26  of the spacer  20 , and a spaced apart position in which, as shown in FIG. 7C, they are adapted to insert the spacer  20  into the tubular part  12 , with operating means  33  adapted to actuate the jaws  32 . 
     In practice the jaws  32  are spring-loaded at all times towards their close together position by springs  34  which bear on the support  31 ; they have on their inside edge a conical or frustoconical surface  35  and the operating means  33  comprise a cam which has a conical or frustoconical surface  36  complementary to their conical or frustoconical surface  35  and is adapted to be inserted between them. 
     In the embodiment shown, complementary nesting means are provided between the spacer  20  and each of the jaws  32  for retaining the spacer  20  on the jaws  32 . 
     In practice, these complementary nesting means are obtained by virtue of the fact that the external edge of the jaws  32  forms a projecting surface  37  with a convex profile complementary to the concave profile of the inside edge  26  of the segments  21  of the spacer  20 . 
     Initially, the spacer  20  is simply forcibly fitted over the jaws  32 , which are in the close together position shown in FIG. 7A, without breaking its areas  22  of reduced strength. 
     Carried by the jaws  32 , the spacer  20  is then inserted into the hole  14  in the tubular part  12 , in the direction of the arrow F 2  in FIG. 7A, until it lies within the interior volume of the tubular part  12 , at equal distances from the walls  15  around the hole  14 , as shown in FIG.  7 B. 
     The operating means  33  are then actuated to move the jaws  32  apart, as shown in FIG. 7C, which subjects the spacer  20  to a radial expansion force causing the segments  21  constituting it to separate from each other and to be forcibly engaged between the walls  15  of the tubular part  12 . 
     The spacer  20  of the invention fitted in this way through the hole  14  in the tubular part  12 , is then thus fragmented circumferentially into as many separate segments  21  as it initially comprises, i.e. two segments  21  in this example. 
     Withdrawal of the operating means  33  then returns the jaws  32  to the close together position as shown in FIG. 7D, and the support  31  is then withdrawn to leave room for the cylindrical part  11 , as shown in FIG.  9 . 
     Because of its thickness E 1  and the bevels  28  on it, the spacer  20 , to be more precise the segments  21  that constitute it, when inserted into the tubular part  12 , push the walls  15  of the tubular part  12  slightly apart. 
     As a result, they are then subjected to an axial clamping force by relaxation of the walls  15  and in practice this axial clamping force is sufficient to hold them in place. 
     Because of the circular contour of its outside edge  25 , the spacer  20  fits closely in the hole  14  in the tubular part  12  whilst having a maximal external diameter and, because of the circular contour of its internal hole  26 , the segments  21  obtained from it then fit closely to the contour of the hole  14 , lying as close as possible to the latter. 
     As can be seen in FIG. 8, the spacer  20  is preferably expanded in the lengthwise direction D of the tubular part  12 , at one end at least of the diameter of the hole  14  in the latter parallel to the lengthwise direction D. 
     In practice, as shown in FIG. 8, the segments  21  of the spacer  20  locate at respective opposite ends of this diameter. 
     FIG. 8 shows that, in the embodiment shown, the spacer  20  formed of the segments  21  extends along at least two-thirds of the perimeter of the hole  14  in the tubular part  12 . 
     When the cylindrical part  11  is inserted in the hole  14  in the tubular part  12 , the segments  21  of the spacer  20  advantageously brace internally the wall  15  of the tubular part  12  on the same side as the cylindrical part  11 , bearing on the opposite side on the wall  15 , which is in turn braced externally by the table  17  of the press. 
     The segments  21  of the spacer  20  then constitute lost parts which remain inside the assembly  10  produced in this manner. 
     It is readily understandable that if the segments  21  encroach slightly on the hole  14  in the tubular part  12 , once fitted as described above, they are pushed further back into the latter by the cylindrical part  11  when the latter is sleeved into it, and the bevel  28  on their inside edge  26  facilitates this. 
     As is also readily understandable, given its symmetry perpendicular to its axis, the spacer  20  is advantageously reversible and can be used either way up. 
     In the embodiments shown in FIGS. 10 and 11 the spacer  20  is formed of three segments  21  that are initially attached together circumferentially in a separable manner by areas  22  of reduced strength. 
     Further, in the embodiment shown in FIG. 11, the segments  21  have on their outside edge  25  flats  38  forming a dihedron between them. 
     Otherwise the arrangements are the same as previously. 
     However, when fitted, the spacer  20  is more uniformly distributed around the hole  14  in the tubular part  12 . 
     Of course, the present invention is not limited to the embodiments described and shown, or to the use described and shown, but naturally encompasses any variant execution thereof. 
     In particular, the hole in the tubular part does not necessarily match in all respects the shape of the periphery of the cylindrical part. 
     In other words, there is not necessarily a continuous contact between the hole and the periphery at all points. 
     It is sufficient for the overall contour of the hole in the tubular part to envelope the overall contour of the periphery, i.e. the cross-section, of the cylindrical part. 
     Further, instead of being initially in one piece with each other, the component segments of the spacer of the invention may originally be separate parts, being held together by a surrounding elastic band, for example. 
     Like the segments themselves, this elastic band then forms a lost part.