Abstract:
In a connecting device, a structural component, a shielding component ( 1 ) in particular, is attached to at least one associated support part ( 9 ) by at least one clamping part ( 11 ). The clamping part, with at least one clamping surface ( 15 ), can be moved into contact with the support part ( 9 ). The clamping surface ( 15 ) is connected to an attachment arm ( 13 ) of the clamping part ( 11 ), and can be advanced non-positively onto the support part ( 9 ) by a feed ( 23, 27 ).

Description:
FIELD OF THE INVENTION 
   The present invention relates to a connecting device for attaching a structural component, a shielding component in particular, to at least one associated support part by at least one clamping part. The clamping part can be moved with at least one clamping surface into contact with the support part. 
   BACKGROUND OF THE PRESENT INVENTION 
   While the heat, such as that evolved by a high-economy, performance-optimized diesel engine, for example, can be very low on the cylinder crankshaft housing, this low heat does not apply to “hot zones” such as in manifolds, turbochargers, catalytic converters, etc. As a result of the increasingly compact design of engines, components which are not thermally “compatible” are coming to be in ever closer proximity. Hence, it is necessary to use shielding components such as heat shields to protect adjacent heat-sensitive assemblies, such as sensors, fuel lines, pressure cells, body parts, and so forth. The situation is also exacerbated by the compact structure in that the high packing density of the assemblies constricts the cooling air flow in the engine compartment. Noise abatement measures can also contribute to this problem. For example, under certain circumstances, plastic floor plates for reducing the level of sound emerging from the engine compartment to the Because of their high surface temperatures in some phases, catalytic converters are among the heat sources which may necessitate the use of protective shield barriers. A typical example is that of design measures, such as positioning the catalytic converter in the immediate vicinity of the manifold. This design principle, which performs the function of rapid heat-up of the catalytic converter, and thus of reducing emissions in the cold start phase, shifts a major source of heat into the engine compartment where a considerable number of assemblies are crowded in a tight space. Another reason for the growing importance of shielding components such as heat shields is the trend toward use of thermoplastics. Light and economical materials with their exceptional moldability are rapidly becoming common in the engine compartment, but require special attention with respect to ambient temperatures generated at the application site in connection with other heat-generating engine parts (New materials and Development Tools for Protection from Heat, in MTZ December 2001, Vol. 72, pp. 1044 et seq.). 
   In addition to the thermal loads to which structural components such as shielding components in particular are exposed in operation, there are mechanical loads, especially due to vibrations transmitted by the support parts to the structural components. In view of these loads, special demands must be imposed on the connecting devices which keep these structural components in position on the pertinent support parts. Conventional connecting devices of the prior art call for spring clamps with a certain pretensioning (clips) which are clamped by stud pins or the like, but also by entire components, for example, solenoid switches of generators, or by exhaust manifolds. The clamping force or holding force results from the choice of the spring material and the structural design of the pertinent springs. As has been found, however, especially when the pertinent structural component is a hot component, the danger exists that fatigue phenomena will occur in the spring material, and will occur to an increased degree when operation-induced vibrations are added. Reliable attachment of the pertinent structural components by the known connecting devices is therefore not ensured. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a connecting device ensuring an especially secure attachment of structural components, even under high continuing thermal and mechanical loads. 
   This object is basically achieved by a connecting device with a non-positive advance of an attachment arm of the clamping part by a feed. The pertinent structural components are therefore clamped with a clamping force effected by the feed in addition to the forces of elasticity or independently of the forces of elasticity so that high operating reliability of attachment of the structural component is achieved. 
   In the prior art, only the spring force of the clamps or clips is available as the clamping force on the pertinent support part. As a result of the fatigue phenomena and vibration loads, the structural component may be displaced or even fall off. 
   Especially simple and reliable attachment arises in exemplary embodiments in which the feed has a locking screw. By the screwing force of the locking screw, the clamping part can be tensioned against the pertinent support part. 
   Preferably, for clamping two support parts located at a distance from each other, the clamping part has two attachment arms extending in directions opposite each other away from the feed shared by the two arms. In these embodiments, the attachment of the pertinent structural component is especially simple, since only one feed, for example, in the form of a locking screw, need be actuated to effect locking to several support parts. In many instances, it is sufficient for the overall mounting of the structural component if a single locking screw is tightened. 
   In especially advantageous embodiments, a mounting part connected to the structural component in the respective clamping region forms second or opposite clamping surfaces which interact with the pertinent clamping surfaces of the clamping part and against which the pertinent support parts can be pressed by the associated first clamping surfaces of the clamping part. The clamping part can be advanced in the direction to the mounting part by the screw force of the locking screw. If in this connection the configuration is such that when the clamping part is advanced in the direction to the mounting part, when the locking screw is being tightened the required clamping force desired for secure attachment is applied to the support parts tensioned between the clamping surfaces even before the clamping part is advanced by the locking screw up to contact with the mounting part. The resulting clamping force is then dependent on how closely the clamping part has approached the mounting part by tightening the locking screw. By more or less strong tightening of the locking screw, i.e., the clamping part more or less approaching the mounting part, the clamping force can be adjusted at will. 
   This embodiment also makes it possible to execute the clamping part as a comparatively rigid component, for example, in the form of a clamping strip with a reinforcing bead. The clamping force is determined here essentially solely according to the screw force of the locking screw. 
   When the required theoretical clamping force on the clamped support parts is achieved in the mounting process before the clamping part is advanced by the locking screw up to contact with the mounting part, a further advantage is that after a correspondingly long operating time has passed, if possibly service measures must be carried out, the locking screw can be retightened to move the clamping part closer to the mounting part. If after extended operating times, due to metal fatigue, for example, a certain relaxation of the clamping force should have occurred, the original desired clamping force can be restored by this retightening. 
   With respect to ease of mounting, it is especially advantageous if one of the arms of the clamping part is lengthened beyond the area of the pertinent clamping surface by an extension. This extension is connected to the mounting part at an attachment point. This arrangement yields a mounting unit in which in the premounted state the clamping part is already captively held on the associated structural component before the locking screw is attached to complete the mounting unit. 
   If in this connection the clamping part is designed as a stiff component, the extension between the attachment point and the transition area to the clamping surface of the adjacent arm has a spring element. The spring element permits essentially unhindered feed motion of the clamping part onto the support parts. 
   The subject matter of the present invention is also a structural component, a shielding component in particular, with a flat operating part and a mounting part connected to it. The mounting part is a component of a connecting device for attaching the structural component to at least one support part. 
   Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
       FIG. 1  is a perspective view, looking at the inside of a structural component in the form of a metallic shell part, forming a shielding component and provided with a connecting device according to the prior art for attaching the structural component to the support parts in the form of cylindrical sleeves; 
       FIG. 2  is a perspective view, looking at the inside of a structural component in the form of a metallic shielding component in the form of a partial shell, according to an embodiment of a connecting device according to the present invention; and 
       FIG. 3  is a perspective view of the structural component shown in  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a structural component in the form of a shielding component  1 . It has the shape of a partial metallic shell with an arched operating part  3 , the interior of which is shown in  FIG. 1 . The structural component is intended as a heat shield or noise-insulating element for the shielding of the corresponding zones or components. The operating part  3  is provided with arched stiffening beads  5  which increase the dimensional stability for its attachment to the associated support parts, and has a connecting device according to the prior art which in the manner conventional in these known devices has clamps of spring steel or spring clips  7 . The spring clips, due to their spring force with clamping surfaces located on the inside of their clamp legs, clamp the pertinent support parts, which are round sleeve bodies  9  in the illustrated example. The sleeve bodies  9  which form the support parts can be penetrated by stud bolts (not shown), for example, in conjunction with cylinder heads, engine blocks or exhaust manifolds of an internal combustion engine or can be connected in some other way to a supporting structure. Likewise the spring clips  7  could form a direct clamp connection on the stud bolts. 
   As already mentioned, in the designs according to the prior art shown in  FIG. 1 , the danger exists that relaxation of the force of elasticity of the clip  7  will occur due to fatigue phenomena and/or thermal loads in operation. Operating reliability then leaves something to be desired. The greatest attainable clamping force is limited at any rate to the spring force of the clips  7 . 
     FIGS. 2 and 3  show one embodiment of the connecting device according to the present invention for attaching a structural component, in the form of a shielding component  1  of the type shown in  FIG. 1 . As in  FIG. 1 , the shielding component  1  forms a flat operating part  3  forming the actual shield wall and having reinforcing beads  5  to increase the structural strength and to optimize the vibration behavior. This arrangement is also important with respect to noise insulation. As in the example of  FIG. 1  corresponding to the prior art, the circular cylindrical sleeve bodies or sleeve parts  9  form the support parts to which the shielding component  1  can be attached and extend parallel to each other at a distance to each other. 
   Instead of using the spring clips  7  shown in  FIG. 1 , the present invention includes at least one clamping part  11  having an attachment arm  13  for each support part to be clamped, that is, here each sleeve body  9 . Each attachment arm  13  is shaped such that in its end area it forms a first clamping surface  15  which surrounds a peripheral section of the respective sleeve body  9  to be clamped and presses that sleeve body against a second or opposite clamping surface  17  located on a mounting part  19 . The mounting part  19  is connected to the operating part  3  of the shielding component  1 , in the example shown here in the form of an edge strip integral with the operating part  3 . This strip is essentially flat, except for the reinforcing bead extending along the edge strip and the arches forming the clamping surfaces  17 . The main plane of the edge strip forming the mounting part  19  extends at a distance parallel to the connecting line between the cylinder axes of the cylindrical sleeve bodies  9  and parallel to these cylinder axes. 
   As shown in  FIGS. 2 and 3 , in the illustrated exemplary embodiment, the clamping part  11  has two arms so that two attachment arms  13  extend from a central area  21  in opposite directions toward the sleeve bodies  9  to be clamped. In the central area  21 , a feed or feed means produces a feed movement of the attachment arms  13  against the sleeve bodies  9  to allow a clamping force to be created on them. In the illustrated embodiment, the feed means includes a locking screw configuration containing a locking screw  23  extending through the mounting part  19 , and having a screw head  25  accessible on the outer side of the mounting part  19  and a rivet nut  27  riveted in the central area  21  of the clamping part  11  on one opening thereof. 
   As  FIG. 2  clearly shows, when the locking screw  23  has been tightened to such an extent that on the clamping surfaces  15  and  17  the clamping force of the desired and necessary strength acts on the sleeve bodies  9 , there is a distance between the clamping part  11  and the inside of the mounting part  19 . This distance means that when the locking screw  23  is tightened more vigorously so that the distance between the central area  21  of the clamping part  11  and the mounting part  19  is reduced, the clamping force produced by the arms  13  by the clamping surface  15  is increased. When the clamping part  11  with the attachment arms  13  is made as a comparatively stiff component, for example, with a reinforcing bead  29  extending in the longitudinal direction ( FIG. 3 ), the strength of the clamping force is essentially directly related to how strongly the locking screw  23  is tightened, i.e., how closely the clamping part  11  has approached the mounting part  19 . 
   As shown in this example, the clamping part  11 , on the end of its one attachment arm  13 , is lengthened by an extension  31 . The extension  31  is connected on the end side at an attachment point  33  to the edge part of the shielding component  1 . This arrangement provides the advantage that when the connecting device is premounted on the shielding component  1 , before the locking screw  23  is used, the clamping part  11  is already captively locked. Before the locking screw  23  engages the rivet nut  27  of the clamping part  11 , the clamping part  11  can be raised relatively far off the mounting part  19 . The insertion of the sleeve bodies  9  between the clamping surfaces  15  and  17  is then facilitated during mounting. 
   To prevent the feed motion produced by the locking screw  23  from being hindered in a comparatively rigid construction of the clamping part  11  in spite of attachment of the extension  31  to the attachment point  33 , it is advantageous to provide a spring configuration  35  on the extension  31  between the attachment point  33  and the transition to the end of the attachment arm  13 . The illustrated exemplary embodiment is a reduced-width point on the extension  31  which forms a shaft shape raised to the inside. This shaft acts both as a spring element to ensure comparatively free mobility of the facing attachment arm  13  of the clamping part  11 , and also as a compensation element for possible thermally induced deformations, such as elongation and stretching. It is within the scope of the present invention to distribute the clamping force applied by the spring configuration  35  between the two sleeve bodies  9 . 
   While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.