SEAT BELT SUSPENDER

Abstract: A seat belt suspender that makes it possible to reduce production costs by reducing material costs for a covering member with continued efforts to improve the safety. A seat belt suspender (10) for slidably suspending a seat belt (a webbing belt) (74) at an intermediate portion therealong where the belt is folded back, the belt capable of being fed out and prevented from being fed out in an emergency, comprises a base member (20) having an elongated hole (22) and made from a metal plate and a synthetic resin covering member (30) adapted to cover the base member (20) at at least the periphery of the elongated hole (22) and having a belt passing hole (31) at a portion corresponding to the elongated hole (22), wherein at least an edge portion (22a) of the elongated hole (22) that corresponds to a portion of the seat belt (74) where it is folded back is formed into a curved surface which is smoothly curved in a direction in which the seat belt (74) is folded back.

Description: Technical Field The present invention relates to a seat belt hanging and holding member for slidingly hanging a seat belt (waving belt) by folding back the intermediate part of the seat belt provided so as to be supplied, like, for example, a three-point type seat belt for an automobile and be prevented from being supplied upon emergency. Background Art In recent years, in order to achieve the safety, upon collision, of members getting on an automobile, a three-point type seat belt for supporting the breast parts of the members riding on the automobile in a crossed fashion as-well as a two-point type seat belt for holding a waist part has been adopted. A seat belt hanging and holding member according to the preamble of claim 1 is generally known on the prior art. In particular: Fig. 43A is a perspective view of the interior of an automobile 1, for explaining the construction of a three-point type seat belt 70. Although the three-point type seat belt may be mounted on all of the front seats and the rear seats of the automobile 1, herein, an example in which it is provided only in a driver's seat 2 will be described for simplicity of explanation. The three-point type seat belt 70 is designed to be put on between the three points of a first anchor 71 provided on the lower part of a center pillar 3, a second anchor 72 mounted on a floor part between a driver's seat 2 and an assistant seat 4 and a third anchor 73 provided on the upper part of the the center pillar 3. The three-point type seat belt 70 comprises a waving belt 74 one end of which is attached to the first anchor 71 and the other end of which is folded back at the part of the third anchor 73 and wound by a retractor (not shown) built in the center pillar 3 and a fixed belt 75 one of which is attached to the second anchor 72 and the other end of which is provided with a buckle 77. A tongue part 76 to be locked in the buckle 77 is provided in an intermediate part of the waving belt 74. Fig. 43B is a perspective view of a conventional seat belt hanging and holding member 78 to be mounted on the third anchor 73. As illustrated in Figs. 43B and 43C, the seat belt hanging and holding member 78 comprises a base member 80 made of a steel plate (metal plate) having a bolt inserting hole 81 and a slot 82 and a coating member 90 made of a synthetic resin for covering the periphery of the slot 82 of the base member 80 and having a seat belt inserting hole 91 formed in the slot 82. The slot 82 is, as shown in Fig. 43C, punched out, throughout its whole periphery, substantially perpendicularly to the surface of the base member 80. Further, the slot 82 comprises, as illustrated in Fig.44, long edge parts 82a and 82b opposed to each other, and short edge parts 82c and 82d for connecting together both the end parts of these long edge parts 82a and 82b. The respective long edge parts 82a and 82b and short edge parts 82c and 82d are, as described above, punched out substantially at right angles with the surface of the base member 80. In addition, the seat belt inserting hole 91 is, as shown in Fig. 44, formed so as to cover the respective long edge parts 82a and 82b and short edge parts 82c and 82d. A part extending along the one long edge part 82a serves as a folding-back and sliding part 91a for slidingly folding back the waving belt 74. The seat belt hanging and holding member 78 constructed as mentioned above is fixed to the third anchor 73 by means of a bolt inserted into the bolt inserting hole 81. Then, the waving belt 74 is slidingly slung and held on the folding-back and sliding part 91a. The waving belt 74 is usually subjected to an aromatic agent process to improve its sliding feature to the coating member 90. Additionally stated, the seat belt hanging and holding member 78 is, as illustrated in Fig. 43A, formed by molding the coating member 90 integrally with the base member 80 in accordance with, what is called, an insert molding. In other words, after the base member 80 is inserted into a metal mold for forming the coating member 90, the metal mold is closed and filled with a resin so that the coating member 90 integral with the base member 80 can be formed. In the case of the above described conventional seat belt hanging and holding member 78, however, since the slot 82 is punched out perpendicularly to the base member 80, the slot 82 is provided with rectangular corner parts. Therefore, rectangular corner parts are formed on the coating member 90 adjacent to the the slot 82. There is a risk that stress is concentrated on such rectangular corner parts. That is, there arises a risk that large stress is liable to be concentrated on the part in contact with the slot 82 in the coating member 90. Therefore, in designing the coating member 90, a large safety factor, which is deemed to be too sufficient, is employed so that the thick coating member 90 is formed. Thus, the coating member 90 is not broken. Accordingly, there has been a problem that a material cost required for the coating member increases, which results in the high cost. Further, in the above mentioned conventional seat belt hanging and holding member 78, as shown in Fig. 44, the waving belt 74 is slidingly slung and held on the folding-back and sliding part 91a. When the waving belt 74 is abruptly pulled, however, as shown in Fig. 45, the waving belt 74 sometimes is moved toward the one short edge part 82c side of the slot 82, or as shown in Fig. 46, the waving belt 74 is concentrically gathered together to the short edge 82c side. Particularly, when the waving belt 74 concentrically comes together to the short edge 82c side, a large force is exerted on the coating member 90 from the base member 80, so that the force acting on the coating member 90 needs to be lowered. Further, in the above mentioned conventional seat belt hanging and holding member 78, there have been problems that the resin tends to leak along the outer peripheral edge parts 83 of the base member 80, as seen in Fig. 47, because of the pressure of the resin in the insert molding. and burs 90a are liable to be produced in the boundary parts 83a between the outer peripheral edges 83 and the coating member 90. Still further, since the base member 80 is generally formed with a carbon steel having, for example, about S55C (SAE1045 to SAE1050), it is subjected to a press molding and then to a thermal treatment so that its strength is improved. Therefore, many production processes are inconveniently needed. Additionally, since deflection is generated on the base member 80 owing to the thermal treatment, when the base member 80 is inserted into the metal mold in order to form the coating member 90 in accordance with the insert molding, an excessive force for correcting the base member to a normal figure is exerted on the metal mold. This undesirably causes the life of the metal mold to be lowered. In addition, when the base member 80 is formed with the material of S55C, there has been a risk that hydrogen brittleness is, during a plating process, generated on the base member 80. Therefore, a thermal treatment to remove the hydrogen brittleness needs to be simultaneously carried out. Consequently, greatly numerous production processes have been disadvantageously required. An object of the present invention is to provide a seat belt hanging and holding member capable of preventing burs formed with the coating member from being produced on the boundary parts between the outer peripheral edge parts of the base member and the coating member. Disclosure of Invention In order to attain the above described object, the invention is defined by the features of claim 1. Further improvements of the seat belt hanging and holding member. are defined in dependent claims 2 to 6. In particular, the invention concerns a seat belt hanging and holding member for slidably hanging and holding a seat belt by folding back an intermediate part of the seat belt which is constructed so as to be supplied and prevented from being supplied upon emergency; the seat belt hanging and holding member comprising: a base member made of a metal plate having a slot into which said seat belt is inserted; and a coating member made of a synthetic resin for covering the periphery of the slot of the base member;the outer peripheral edge parts of the base member being provided with step parts set lower by one step in the boundary parts between the edge parts and the coating member. Brief Description of Drawings Fig. 1 shows a seat belt hanging and holding member not belonging to the invention. Fig. 1A is a perspective view, Fig. 1B is a sectional view taken along a line I-I of Fig. 1A and Fig. 1C is a front view showing a base member. Fig. 2 is an explanatory view showing a first production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 3 is an explanatory view showing a second production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 4 is an explanatory view showing a third production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 5 is an explanatory view showing a fourth production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 6 is an explanatory view showing a fifth production process when the base member of the seat belt hanging and holding member is manufactured. Fig, 7 is an explanatory view showing a sixth production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 8 is an explanatory view showing a seventh production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 9 shows a seat belt hanging and holding member not belonging to the invention. Fig. 9A is a perspective view, and Fig. 9B is a sectional view taken along a line II-II of Fig. 9A. Fig. 10 shows protruding parts formed on the seat belt hanging and holding member, Fig. 10A is an explanatory view showing the first sectional shape of the protruding part, Fig. 10B is an explanatory view showing the second sectional shape of the protruding part and Fig. 10C is an explanatory view showing the third sectional shape of the protruding part. Fig. 11 shows a seat belt hanging and holding member illustrated as a first alternative example of the example shown in Fig 9 and an enlarged sectional view of a position corresponding to the part B of Fig, 9B, not belonging to the invention. Fig. 12 shows the seat belt hanging and holding member of the first alternative example, Fig. 12A is an enlarged sectional view of a position corresponding to a section taken along a line A-A of Fig. 9A. Figs. 12B and 12C are enlarged sectional views illustrating examples in which the forms of grooves between the protruding parts in Fig. 12A; not part of the invention. Fig. 13 is a front view of a seat belt hanging and holding member shown as a second alternative example, not belonging to the invention. Fig. 14 is a seat belt hanging and holding member shown as a third alternative example, Fig. 14A is a front view, Fig. 14B is a sectional view taken along a line III-III of Fig. 14A and Fig. 14C is an enlarged view showing a part D of Fig. 14A; not belonging to the invention. Fig. 15 is a perspective view of a seat belt hanging and holding member illustrated as a fourth alternative example, not belonging to the invention. Fig. 16 shows a further seat belt hanging and holding member and a sectional view of a position corresponding to the position taken along the line I-I of Fig. 1; not belonging to the invention. Fig. 17 is an explanatory view showing a fifth production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 18 is an explanatory view showing a sixth production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 19 is an explanatory view showing a seventh production process when the base member of the seat belt hanging and holding member is manufactured. Fig. 20 shows an alternative example of the base member of the seat belt hanging and holding member, Fig. 20A is a front view and Fig. 20B is a sectional view. Fig. 21 shows a seat belt hanging and holding member Fig. 21A is a perspective view, Fig. 21B is a front view showing a base member and Fig. 21C is a sectional view taken along a line IV-IV of Fig. 21B; not belonging to the invention. Fig. 22 shows a seat belt hanging and holding member (not belonging to the invention) and a sectional view corresponding to the sectional position taken along the line IV-IV of Fig. 21B. Fig. 23 shows a seat belt hanging and holding member illustrated as an embodiment of the present invention, Fig. 23A is a perspective view, Fig. 23B is a front view showing a base member and Fig. 23C is a sectional view of the seat belt hanging and holding member in a position corresponding to a line V-V of Fig. 23B. Fig. 24 shows a seat belt hanging and holding member illustrated as a second embodiment of the present invention, Fig. 24A is a front view showing a base member and Fig. 24B is a sectional view of the seat belt hanging and holding member in a position corresponding to a line VI-VI of Fig. 24A. Fig. 25 is a front view showing the operational effect of the seat belt hanging and holding member. Fig. 26 is a front view showing the operational effect of the seat belt hanging sling and holding member. Fig. 27 shows a seat belt hannging and holding member illustrated as a third embodiment of the present invention and is a front view showing a base member. Fig. 28 is a sectional view of a seat belt hanging and holding member illustrated as a fourth embodiment of the present invention. Fig. 29 is a front view showing a base member of a seat belt hanging and holding member illustrated as a fifth embodiment of the present invention. Fig. 30 is a sectional view of the seat belt hanging and holding member taken along a line VII-VII of Fig. 29. Fig. 31 is a front view showing a base member of a seat belt hanging and holding member illustrated as an sixth embodiment of the present invention. Fig. 32 is a front view showing a base member of a seat belt hanging and holding member illustrated as a seventh embodiment of the present invention. Fig. 33 is a front view showing a base member of a seat hanging and holding member illustrated as a eighth embodiment of the present invention. Fig. 34 is a front view showing a base member of a seat belt hanging and holding member illustrated as a ninth embodiment of the present invention. Fig. 35 is a sectional view showing the reinforcing part of the seat belt hanging and holding member. Fig. 36 is a sectional view showing an alternative example of the reinforcing part of the seat belt hanging and holding member. Fig. 37 shows a base member of a seat belt hanging and holding member illustrated as a tenth embodiment of the present invention, Fig. 37A is a front view, Fig. 37B is an enlarged view showing a step part, Fig. 37C is an enlarged view showing a first alternative example of the step part and Fig. 37D is an enlarged view showing a second alternative example of the step part. Fig. 38 is a plan view of a high-tension steel plate showing first to third processes for manufacturing the base member of the seat belt hanging and holding member. Fig. 39 is a plan view of the high-tension steel plate showing fourth to fifth processes for manufacturing the base member of the seat belt hanging and holding member. Fig. 40 is a plan view of the high-tension steel plate showing sixth to seventh processes for manufacturing the base member of the seat belt hanging and holding member. Fig. 41 is a plan view of the high-tension steel plate showing eighth to tenth processes for manufacturing the base member of the seat belt hanging and holding member. Fig. 42 is a plan view of the high-tension steel plate showing tenth to eleventh processes for manufacturing the base member of the seat belt hanging and holding member. Fig. 43 is a view for explaining the construction of a three-point type seat belt, Fig. 43A is a perspective view showing the whole construction of the three-point type seat belt, Fig. 43B is a perspective view showing a conventional seat belt hanging and holding member, and Fig.43C is a sectional view taken along a line X-X of Fig. 43B. Fig. 44 is a front view showing a conventional seat belt hanging and holding member. Fig. 45 is an explanatory view showing the problem of the above seat belt hanging and holding member. Fig. 46 is an explanatory view showing the problem of the above described seat belt hanging and holding member. Fig. 47 is a front view of a seat belt hanging and holding member illustrated as an alternative conventional example. Best Mode for Carrying Out the Invention Now, referring to the drawings, embodiments of the present invention will be described hereinafter. Initially, a first seat belt hanging and holding member will be described with reference to Figs. 1 to 8. Herein, components common to the components of the conventional example illustrated in Fig. 43 are affixed by the same reference symbols as those of the conventional example and an explanation therefor will be omitted. Fig. 1A is a perspective view illustrating the construction of a seat belt hanging and holding member 10 attached to the third anchor 73 of the center pillar 3 of an automobile, as has been explained in Fig. 43A. Fig. 1B is a sectional view taken along a line I-I of the seat belt hanging and holding member 10 shown in Fig. 1A. Fig. 1C shows a front view of only a base member 20 of the seat belt hanging and holding member 10 before a coating member 30 is mounted thereon. Further, Figs. 2 to 8 are explanatory views showing the respective production processes of the base member 20. The seat belt hanging and holding member 10 is, as illustrated in Figs. 14 1A, 1B and 1C, manufactured by inserting and molding the coating member 30 onto the base member 20. The base member 20 is formed by punching out a steel plate material (metal plate) having thickness of about 3 mm and press-working it and comprises an attaching part 20A and a seat belt holding part 20B which are formed integrally with each other. The seat belt holding part 20B is, as shown in Fig. 1B, bent or folded by a prescribed angle (30° or thereabout) relative to the attaching part 20A. A bolt inserting hole 21 is opened on the attaching part 20A in order to attach the seat belt hanging and holding member 10 to the third anchor 73 (see Fig. 43A) of the center pillar 3 of the automobile. A slot 22 is opened in the seat belt holding part 20B. The slot 22 has, as shown in Fig. 1B, one edge part 22a extending in its longitudinal direction which swells in an elliptical shape. The edge part 22a is located at a position where a waving belt (seat belt) 74 (see Figs. 1Band 43A) is folded back and formed in a curved shape smoothly turned along the direction in which the waving belt 74 is folded back. The coating member 30 is, in the present example, provided in the periphery of the slot 22 of the seat belt holding part 20B of the base member 20so as to cover the base member 20 by an insert-molding, and has a part corresponding to the slot 22 which serves as a seat belt inserting hole 31 into which the waving belt 74 is inserted. In the case of the conventional seat belt hanging and holding member 78 explained in Fig. 43C, the edge part 82a of the slot 82 is cut perpendicularly to the slot 82 , so that the rectangular corner parts are formed in the edge part 82a. As a result, large stress concentration has been generated on the position corresponding to the edge part 82a in the coating member 90. On the other hand, however, since the edge part 22a of the slot 22 is curved in a curved surface, in the present embodiment, only an exceedingly small stress concentration is generated in the coating member 30 in contact with the edge part 22a. Reference symbol T in the drawings designates protruding parts T which protrude at prescribed pitches in the circumference of the bolt inserting hole 21. The protruding parts T serve as a rotation stopper of a bolt (not shown) when the seat belt hanging and holding member 10 is attached to the third anchor 73 (see Fig. 43A) of the center pillar 3 of the automobile by means of the bolt and exhibit the effect of a conventional washer. As a result, since an ordinarily employed washer is not needed when the seat belt hanging and holding member 10 is attached to the anchor, the number of parts can be decreased. Next, a method for manufacturing the part of the slot 22 in the base member 20 will be described, referring to Figs. 2 to 8. Initially, in a first process as shown in Fig. 2, a first lower hole S1 for forming the slot 22 on a steel plate S as a material of the base member 20 by using a lower metal mold K1 and a punch K2. Then, in a second process as illustrated in Fig. 3, a circular arc shaped roundness Sla is formed from the upper part of the first lower hole S1 to the upper surface of the steel plate S by using a lower metal mold K3 and an upper metal mold K4. Further, in a third process as illustrated in Fig. 4, a circular arc shaped roundness S1b is formed from the lower part of the first lower hole S1 to the lower surface of the steel plate S by using a lower metal mold K5 and an upper metal mold K6. Thereafter, in a fourth process as seen in Fig. 5, the part of the first lower hole S1 is curved toward the upper part of the steel plate S so that a second lower hole S2 is formed. Then, in a fifth process as illustrated in Fig. 6, the part of the second lower hole S2 protruding upward is face-pressed downward by using a lower metal mold K9, an upper metal mold K10 and an intermediate metal mold 11, so that protruding parts S3 and S4 are formed which have substantially the same height from the upper and lower surfaces of the steel plate S. Further, in a sixth process as shown in Fig. 7, the protruding part S3which protrudes upward is machined so as to be formed in an entirely smoothly curved surface by employing a lower metal mold K12 and an upper metal mold K13. At this time, the surface of the second lower hole S2 is also neatly machined. Then, in a seventh process as shown in Fig. 8, the protruding part S4 which protrudes downward is machined so as to be formed in an entirely smoothly curved surface by using a lower metal mold K14 and an upper metal mold K15. Also at this time, the surface of the second lower hole S2 is neatly machined. Thus, the slot 22 is formed by the second lower hole S2 machined in such a way. Further, the edge pat 22a is formed with the protruding parts S3 and S4 so as to expand in an elliptical shape relative to the steel plate S. In such a manner, the base member 20 having the slot 22 is made from the steel plate S. In this case, the base member 20 is formed in accordance with a cold-working. Although the method for manufacturing the base member 20 has been described by dividing it into the seven processes illustrated in Figs. 2 to 8, as mentioned above, in practice, the method is divided into more processes and utilizes a technique for forming the base member while the steel plate is gradually deformed. According to the seat belt hanging and holding member 10 constructed as described above, if the waving belt 74 is in a state where it can be supplied, the waving belt 74 can be slidingly supplied while the intermediate part of the waving belt 74 is folded back on the coating member 30, by pulling the waving belt 74. When the waving belt 74 is stopped from being supplied, however, a force for pulling the waving belt 74 is directly exerted on the coating member30. The force directly applied to the coating member 30 is directly exerted on the edge part 22a of the slot 22 of the base member 20 through the coating member 30. The coating member 30 undergoes a reaction force, as its reaction, of the same magnitude as that applied to the edge part 22a, from the edge part 22a of the slot 22. However, since the edge part 22a corresponding to at least the position in the slot 22 where the seat belt is folded back is formed in a curved surface smoothly curved along the direction in which the waving belt 74 is folded back, the stress concentration of the coating member 30 in contact with the edge part 22a of the slot is significantly lowered. Therefore, even if the coating member 30 undergoes a force from the edge part 22a of the slot 22, large stress is not generated in the coating member 30, so that its strength is substantially more increased than a conventional one. Accordingly, the more the strength is increased, the more the thickness of the coating member 30 can be reduced, so that the material cost of the coating member 30 can be lowered without lowering safety owing to the deterioration of the strength of the coating member 30. Thus, the cost can be lowered. Further, since the edge part 22a of the slot 22 swells to one surface side and to the other surface side of the base member 20, the radius of curvature of the edge part 22a can be increased. Therefore, the stress concentration of the coating member 30 in contact with the edge part 22a can be completely decreased. In addition, since the face pressure exerted on the coating member 30 from the edge part 22a can be decreased, a force applied to the coating member 30 from the base member 20 can be furthermore softened. Additionally, since the thickness of the coating member 30 is set by employing an excessively sufficient safety factor, the coating member 30 should not be damaged. If the coating member 30 should be damaged, however, the waving belt 74 would not collide with the edge part 22a of the slot 22 so that it would be cut, because the edge part 22a in the slot 22 corresponding to the position where the waving belt 74 is folded back is formed in a curved surface. In other words, if the coating member 30 should be broken, safety by the waving belt 74 could be ensured. Further, if the coating member should be damaged, the waving belt 74would not be cut. Therefore, the coating member 30 may be formed in a thinner shape. Now, referring to Fig. 9, an other seat belt hanging and holding member will be described. Fig. 9A is a perspective view showing the construction of a seat belt hanging member 10. Fig. 9B is a sectional view taken along a line II-II of Fig. 9A. Herein, components common to those in the example illustrated in Fig. 1 are affixed by the same reference symbols as those in Fig. 1 and an explanation therefor is omitted. The second example is different from the first example in that protruding parts 30a and 30b are formed on the coating member 30. That is, a plurality of protruding parts 30a and 30b are formed in the positions corresponding to the parallel edge parts 22a and 22b (an edge near the bolt inserting hole 21 is designated by the reference symbol 22b and an edge remote from the inserting hole 21 is designated by the reference symbol 22a) in the slot 22, as seen in Figs. 1A and 1B. These protruding parts 30a and 30b are formed in parallel with the direction in which the waving belt 74 is inserted. In the second example, about eleven lower protruding parts 30a are formed and about nine upper protruding parts 30b are formed. Although the protruding parts 30b are provided on the upper side of a seat belt inserting hole 31, in the second embodiment, these protruding parts 30b may be saved, since the waving belt does not always slide on the protruding parts 30b. Fig. 10A shows an example of the sectional shape of the protruding parts 30a or 30b illustrated in Fig. 9A. The protruding parts 30a and 30b shown in the above example comprise a plurality of circular arc shaped protrusions adjacent to one another. The width W1 of each protruding part 30a or 30b is approximately 4 mm, the height H1 thereof is approximately 0.8 mm and the radius R1 of the circular arc is approximately 2mm. Fig. 10B shows an alternative example of the sectional shape of the protruding parts 30a or the 30b shown in Fig. 9A. The protruding parts 30a and 30b illustrated in the present example comprise circular arc shaped crests and troughs which are alternately arranged. A pitch W2 from a trough to a trough is about 4mm, height H2 is about 0.8mm and each radius R2 or R3 of the crest or and the trough is about 1mm. Fig. 10C shows a still another example of the sectional shape of the protruding parts 30a or 30b illustrated in Fig. 9A. The protruding parts 30a and 30b shown in the present comprise a plurality of protrusions formed in trapezoidal shapes which are adjacent to one another. The width W3 of each protrusion 30a or 30b is about 4 mm, and the height H1 thereof is about 0.8mm. These protruding parts 30a and 30b can be also formed by forming V-grooves 30c on the flat coating member 30. As illustrated above, the protruding parts 30a and 30b are formed in the seat belt inserting hole 31 of the coating member 30, so that the contact area between the coating member 30 and the waving belt 74 is decreased, and therefore, a frictional force exerted on the waving belt 74 can be decreased. As a result, a resistance when the waving belt 74 moves in the slot 22 is reduced, and a lubricant such as an aromatic agent is hardly peeled off from the waving belt 74, so that there scarcely arises a failure to wind the waving belt on retractor. Further, since the protruding parts 30a and 30b are extended in the direction along which the waving belt 74 slides, the waving belt 74 is not suddenly biassed to one side of the slot 22 even when the supply of the waving belt 74 is stopped upon collision of the automobile. Therefore, a large friction is not instantaneously generated between the waving belt 74 and the coating member 30, so that the temperature of a part between the waving belt 74 and the coating member 30 becomes high. Thus, the quality of the waving belt 74 is not deteriorated and a failure to wind the waving belt 74 on the retractor can be prevented from occurring. Further, since both the protruding parts 30a and 30b or only the protruding parts 30a are provided on the coating member 30, dusts or the like drop into the groove parts between the protruding parts 30a, or between the protruding parts 30b. Thus, the part of the coating member 30 which abuts against the waving belt 74 is hardly stained and the generation of static electricity can be suppressed (if a static electricity eraser is added to the coating member 30, the generation of the static electricity can be still more suppressed). Accordingly, the waving belt 74 may easily move in the seat belt inserting hole 31. As a result, the waving belt 74 can be smoothly pulled out from the retractor, or wound on the retractor. Fig. 11 shows a seat belt hanging and holding member illustrated as a first alternative example of the second example and is an enlarged sectional view of a part corresponding to a part B of the seat belt hanging and holding member 10 shown in Fig. 9B. On the coating member 30 illustrated in Fig. 11 , an elongated groove 30d, is provided, which extends in the direction perpendicular to the extending direction of the protruding part 30a. Only a a single groove 30d is provided in a part opposed to the folded-back part 74a of the waving belt 74 inserted into the seat belt inserting hole 31. In this case, a plurality of grooves 30d' may be provided in parallel with the groove 30d, as shown by dashed lines in Fig. 11. The above mentioned grooves 30d and 30d' can reduce the friction caused between the waving belt 74 and the coating member 30 made of a synthetic resin. Fig. 12A shows a seat belt hanging and holding member 10 illustrated in Fig. 11 and is an enlarged sectional view of a part corresponding to a sectional view taken along a line A-A of Fig. 9A . Figs. 12B and 12C are enlarged sectional views showing examples in which the forms of grooves 30e between the protruding parts 30a in Fig. 12A are modified. Fig. 13 shows the construction of a seat belt hanging and holding member10 illustrated as a second alternative example of the second example. The construction of the seat belt hanging and holding member 10 is substantially the same as that of the seat belt hanging and holding member 10 described in Fig. 9A. A difference therebetween resides only in that elongated grooves 30f are formed in the vicinity of both the end parts of the protruding parts 30a of the coating member 30 in their extending direction, and along the longitudinal direction of the waving belt 74. The elongated grooves 30f are also designed as one of measures (referred to as a gum-up means) for lowering the friction between the waving belt 74 and the coating member 30. Fig. 14A is a front view of a seat belt hanging and holding member 10 illustrated as a third alternative example of the second example. Fig. 14B is a sectional view taken along a line III-III of Fig. 14A. In the third alternative example, the protruding parts 30b are not provided in the upper side of the seat belt inserting hole 31 and the protruding parts 30a are formed only in the lower side. Further, in the present example, the coating member 30 is formed substantially in a U shape so as to meet the shape of the slot 22 of the base member 20. In addition, as shown in Fig. 14B, a single groove 30d is provided in a part opposed to the folded-back part 74a (see Fig.11) of the waving belt 74, in the lower side part of the seat belt inserting hole 31. Fig. 14C is a partly enlarged view for explaining the shape of a part D of Fig. 14A and describes specifically the shapes of recessed holes 30g respectively provided in the coating member 30 which correspond to both the end parts of the slot 22. The width W6 of the entrance part of the recessed hole 30g is 2 to 3mm, the central width W4 + W5 of the recessed hole 30g is approximately 7mm, the radius R5 of the inside circular arc of the recessed hole 30g is about 6 mm, and the radius R6 of the outside circular arc of the recessed hole 30g is about 6mm. Further, the radius R7 of an inside circular arc in the entrance part of the recessed hole 30g is about 7mm. Fig. 15 is a perspective view of a seat belt hanging and holding member 10 illustrated as a fourth alternative example of the second example. The same components as those of the seat belt hanging and holding member 10 of the second embodiment explained in Fig. 9A are affixed by the same reference symbols and the explanation thereof will be omitted. The seat belt hanging and holding member 10 of the fourth alternative example is different from the seat belt hanging and holding member 10 illustrated in Fig. 9A only in that a plurality of dome shaped protrusions 30h are successively arranged along the longitudinal direction of the waving belt 74, in the lower side part of the seat belt inserting hole 31, in place of a plurality of protruding parts provided along the longitudinal direction of the waving belt 74. When a plurality of dome shaped protrusions 30h are successively arranged on the coating member 30 in such a manner, the contact area between the waving belt 74 and the coating member 30 can be similarly decreased and a friction to the waving belt 74 can be lowered. Consequently, a resistance when the waving belt 74 moves in the seat belt inserting hole 31 is decreased, the aromatic agent is hardly separated from the waving belt 74 and a trouble to wind the belt on the retractor hardly arises. It is to be understood that the shape of the protrusion 30h is not limited to a spherical shape. Now, with reference to Figs. 16 to 19, a third embodiment of the present invention will be described. Herein, components common to the first example shown in Figs. 1 to 8 are affixed by the same symbols as those employed in the first embodiment and the explanation thereof will be simplified. Fig. 16 shows a seat belt hanging and holding member 10 of the third example of the and a sectional view corresponding to a sectional view taken along aline I-I of Fig. 1 and Figs. 17 to 19 are explanatory views for explaining only processes different from the production processes shown in Figs. 2 to 8. The third example is different from the first example in that the edge part 22a swells only to one surface side of the seat belt holding part 20B. Specifically stated, the edge part 22a expands only to one surface side of the seat belt holding part 20B, and the side to which the edge part swells and the side to which the edge part does not swell are similarly formed in a smoothly curved surface along the direction in which the waving belt 74 is reflected. In the present embodiment, the edge part 22a is formed in the same shape throughout all the periphery of the slot 22. The seat belt hanging and holding member 10 constructed as described above is manufactured in accordance with processes illustrated in Figs. 17 to 19. Preprocesses of Fig. 17 are common to the respective processes shown in Figs. 2 to 5. Namely, the part of the first lower hole S1 is curved above the steel plate S in accordance with the fourth process shown in Fig. 5 so that the second lower hole S2 is formed. Then, in a fifth process shown in Fig. 17, the part of the second lower hole S2 protruding upward is face-pressed downward by using a lower metal mold K15 and an upper metal mold K16, so that a protruding part S3 protruding with a substantially constant height from the upper surface of the steel plate S is formed. Further, in a sixth process as illustrated Fig. 18, an edge S5 opposite to the protruding part S3 protruding upward is machined so as to form a smoothly curved surface by employing a lower metal mold K17 and an upper metal mold K18. At this time, the surface of the second lower hole S2 is also neatly finished. Then, in a seventh process as illustrated in Fig. 19, the protruding part S3 protruding upward is finished so as to form an entirely smoothly curved surface by using a lower metal mold K19 and an upper metal mold K20. Also, at this time, the surface of the second lower hole S2 is cleanly finished. Thus, the slot 22 is formed by the second lower hole S2 finished in such a way. Still further, the edge part 22a protrudes in the shape of a smoothly curved surface on the upper surface side of the steel plate S by means of the protruding part S3 and the edge S5. The seat belt hanging and holding member 10 constructed as mentioned above exhibits similar operational effects to those of the first embodiment. Although the edge part 22a is formed so as to swell in an elliptical shape in the first and second embodiments, the edge part 22a may be formed so as to swell in a circular shape or in other shapes of a smoothly curved surface. Additionally, although the edge part 22a swelling in an elliptical shape is formed in all the periphery of the slot 22 in the above embodiments, it is to be noted that the edge part 22a formed in such a fashion can be provided only in a position corresponding to a part on which the waving belt 74 is folded back (see Fig. 20). Further, although the edge part 22a described in the third embodiment is also formed throughout all the periphery of the slot 22, the edge part 22a may be provided only in a part on which the waving belt 74 is folded back (see 20). Next, referring to Fig. 21, a fourth embodiment of the present invention will be described hereinafter. Herein, components common to those of the conventional example are affixed by the same reference symbols as those of the conventional example and the explanation thereof will be omitted. Fig. 21A is a perspective view showing the construction of a seat belt hanging and holding member 10 attached to the third anchor 73 of the center pillar 3 of the automobile, which has been described in Fig. 43A. Fig. 21B is a front view showing the base member 20 of the seat belt hanging and holding member 10. Fig. 21C is a sectional view taken along a line IV-IV of Fig. 21B. The seat belt hanging and holding member 10 is, as illustrated in the respective figures of Fig. 21, formed by inserting and molding a coating member 30 to the base member 20. The base member 20 is formed by punching out a steel plate (metal plate) material having thickness of 3mm or thereabout and press-working it and comprises an attaching part 20A and a seat belt holding part 20B. The seat belt holding part 20B is, as illustrated in Fig. 21C, bent by a prescribed angle (about 30° ) relative to the attaching part 20A. On the attaching part 20A, a bolt inserting hole 21 is opened. On the seat belt holding part 20B, the slot 22 is opened. The slot 22 is, as shown in Fig. 21B, provided with long edge parts 22a and 22b opposed to each other and short edge parts 22c and 22d formed in a curved surface so as to be connected to both the end parts of these long edge parts 22a and 22b. The respective long edge parts 22a and 22b are punched out substantially at right angles with the surface of the base member 20. Further, the short edge parts 22c and 22d are, as illustrated in Figs. 21B and 21C, formed in an elliptical shape in section by swelling parts 22e swelling respectively to one surface side and the other surface side of the base member 20. Specifically stated ,the short edge parts 22c and 22d are formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 is reflected, by the swelling parts 22e which swell toward one surface side and the other surface side of the base member 20. Additionally, in the present embodiment, the respective swelling parts 22e are also continuously formed at both the end parts of the long edge parts 22a and 22b which are adjacent to the short edge parts 22c and 22d. That is, the respective swelling parts 22e are formed in the parts to which the waving belt 74 is concentrically gather when the waving belt 74 is abruptly pulled or the like. Besides, the respective swelling parts 22e are formed in accordance with a cold-working by bending a part of the base member 20 to one surface side, moving the bent part to the other surface side and shaping it in the shape of a curved surface. Accordingly, the respective swelling parts 22e have the large amount of swelling from the base member 20 and are excellent in their strength. The coating member 30 is formed in accordance with an insert-molding so as to cover the periphery of the slot 22 of the base member 20 and has a part opened corresponding to the slot 22 which serves as a seat belt inserting hole 31. The seat belt inserting hole 31 has a part along the long edge part 22a remote from the bolt inserting hole 31, which serves as a folding-back and sliding part 31a on which the waving belt 74 is folded back and slidingly supported. Further, as illustrated in Fig. 21A, protrusions T protrude at prescribed intervals in the periphery of the bolt inserting hole 21. These protrusions T serve as a rotation stopper of a bolt when the seat belt hanging and holding member 10 is attached to the anchor 73 (see Fig. 43A) of the center pillar 3 of the automobile by means of a bolt (not shown) and achieve the effect of a conventional washer. As a result, since an ordinarily used washer is not needed when the seat belt hanging and holding member 10 is attached to the anchor, the number of parts can be decreased. In the seat belt hanging and holding member 10 constructed as described above, since the short edge parts 22c and 22d of the slot 22 and the end parts of the long edge parts 22a and 22b adjacent to them are formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 is folded back, the stress concentration of the coating member 30 in contact with the short edge parts 22c and 22d, and the end parts of the long edge parts 22a and 22b can be extremely reduced. Therefore, even when the waving belt 74 gathers to, for example, the short edge 22c side of the slot 22, a force exerted on the coating member 30 from the short edge part 22c can be distributed. Thus, the force exerted on the coating member 30 from the base member 20 can be softened. Further, since the swelling parts 22e are formed in the short edge parts 22c and 22d, and the end parts of the long edge parts 22a and 22b adjacent thereto, a face pressure acting on the coating member 30 from the short edge parts 22c and 22d and the end parts of the long edge parts 22a and 22b can be decreased. Therefore, the force exerted on the coating member 30 from the base member 20 can be still more decreased. Now, an other seat belt hanging and holding member of the present invention will be described, with reference to Fig. 22. Herein, components common to those of the fourth embodiment seen in Fig. 21 are affixed by the same reference symbols as those of Fig. 21 and the explanation thereof will be omitted. This example is different from the fourth example in that swelling parts 22e swell only to one surface side of the base member 20. The above mentioned swelling parts 22e are, similarly to the fourth example, formed so as to be connected from both the end parts of the long edge parts 22a and 22b to the whole parts of the short edge parts 22c and 22d. The parts having the swelling parts 22e are formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 is reflected. The swelling parts 22e are formed in accordance with a cold-working by bending a part of the base member 20 to one surface side and shaping the bent part in a curved surface. Thus, the swelling parts 22e have the large amount of swelling from the base member 20 and is excellent in view of strength. The seat belt hanging and holding member 10 constructed as stated above also attains similar operational effects to those of the fourth example. Although, the swelling parts 22e are formed on the short edge parts 22c and 22d or the end parts of the long edge parts 22a and 22b continued thereto to which the waving belt 74 concentrically come together when the waving belt 74 is suddenly pulled or the like, it is to be noted that the short edge parts 22c and 22d or the end parts of the long edge parts 22a and 22b connected thereto can be formed in the shape of a smoothly curved surface simply along the direction in which the waving belt 74 is folded back without providing the swelling parts 22e in this way. In this case, since the radius of curvature of the curved surface is decreased, when the swelling parts 22e are not provided, the stress concentration of the coating member 30 coming into contact with the short edge parts 22c, 22d or the like is increased. Besides, a face pressure acting on the coating member 30 from the short edge parts 22c, 22d or the like is also increased. Therefore, it is desirable to provide the swelling parts 22e on the short edges 22c , 22d or the like. It is also apparent that the short edges 22a and 22b or the end parts of the long edge parts 22a and 22b may not be provided with the swelling parts 22e nor be formed in the shape of a curved surface in a part to which the waving belt 74 does not concentrically gather. Now, referring to Fig. 23, an embodiment of the present invention will be described below. Herein, components common to those of a conventional example illustrated in Figs. 43 and 47 are affixed by the same reference symbols as those in these figures and the explanation thereof will be omitted. Fig. 23A is a perspective view showing the construction of a seat belt hanging and holding member 10 attached to the third anchor 73 described in connection with Fig. 43. Fig. 23B is a front view showing the base member 20 of the seat belt hanging and holding member 10. Fig. 23C is a sectional view of the seat belt hanging and holding member 10 taken along a line V-V of Fig. 23B. The seat belt hanging and holding member 10 is, as illustrated in Figs. 23A to 23C, by inserting and molding (injection molding) the coating member 30 to the base member 20. The base member 20 is formed by punching out a steel plate (metal plate) material having thickness of 3mm or thereabout and press-working it and comprises an attaching part 20A and a seat belt holding part 20B. The attaching part 20A and the seat belt holding part 20B are, as seen in Fig. 23C, bent by prescribed angle (about 30° ) with respect to a bending part L. As illustrated in Fig. 23B, a bolt inserting hole 21 is opened on the attaching part 20A, and a slot 22 into which the waving belt (seat belt) 74 is inserted is opened on the seat belt holding part 20B. The slot 22 comprises linear long edge parts 22a and 22b opposed to each other and curved short edge parts 22c and 22d formed so as to connect together both the end parts of the long edge parts 22a and 22b. The slot 22 comprising the respective long edge parts 22a and 22b, and the respective short edge parts 22c and 22d is, as seen in Fig. 23C, punched out substantially at right angles with the surface of the base member 20. The coating member 30 is inserted and molded to the base member 20 so as to cover the periphery of the slot 22 of the base member 20 and has a seat belt inserting hole 31 opened at a part corresponding to the slot 22. Further, the seat belt inserting hole 31 is provided with a part along the long edge part 22a located in the side remote from the bolt inserting hole 21 as a folding back and sliding part 31a for folding back and slidingly supporting the waving belt 74. As illustrated in Figs. 23A to 23C, protrusions T protrude at prescribed pitches in the periphery of the bolt inserting hole 21. These protrusions T serve as a rotation stopper of a bolt (not shown) when the seat belt hanging and holding member 10 is attached to the third anchor 73 (see Fig. 43) of the center pillar 3 of the automobile by means of a bolt and exhibits the effect of a conventional washer. Consequently, when the seat belt hanging and holding member 10 is attached to the anchor, an ordinarily employed washer is not required, so that the number of parts can be decreased. Additionally stated, the base member 20 is, as seen in Figs. 23A to 23B, provided with a step part 24 formed so as to be lower by one step than an outer peripheral edge part 23 in the boundary part 23a between the outer peripheral edge part 23 and the coating member 30. The step part 24 is formed substantially at right angles with the outer peripheral edge part 23, and so as to have such a height that the surface of the coating member 30 is substantially flush with the surface of the outer peripheral edge part 23. In other words, the outer peripheral edge part 23 of the base member 20 has a part, located in the coating member 30 side, which is formed lower by the thickness of the coating member 30 by providing the step part 24. In the seat belt hanging and holding member 10 constructed as mentioned above, the base member 20 is initially inserted into a metal mold, and then, the metal mold is closed. Then, a space corresponding to the coating member 30 in the metal mold is injection-filled with a resin. Thus, the coating member 30 is molded integrally with the base member 20. The coating member 30 is formed integrally with the base member 20 in accordance with a so-called insert-molding. Since the outer peripheral edge part 23 of the base member 20 is provided with the step part 24 set lower by one step in the coating member 30 side, the resin can be prevented, upon insert-molding, from leaking along the outer peripheral edge 23 from the boundary part 23a. Accordingly, burs formed with the coating member 30 can be prevented from being produced in the boundary part 23a between the base member 20 and the coating member 30. Besides, although the leakage of the resin as mentioned above has been conventionally prevented by setting a metal closing force to a high level, the metal closing force does not need to be set to such a high level, since the leakage of the resin can be prevented as stated above. Thus, the durability of the metal mold can be improved. Now, referring to Figs. 24 to 26, a second embodiment of the present invention will be described. Herein, components common to those shown in the first embodiment are affixed by the same reference symbols as those in the first embodiment and the explanation thereof will be omitted. The second embodiment is different from the first embodiment in that the end parts of a slot 22 in its longitudinal direction swell to one surface side and the other surface side of the base member and are formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 (seat belt) is reflected. Specifically stated, short edge parts 22c and 22d are, as illustrated in Figs. 24A and 24B. formed in an elliptical shape in section by forming swelling parts 22e which respectively swell to one surface side and the other surface side of the base member 20. Further, in the present embodiment, the respective swelling parts 22e are continuously formed similarly at both the end parts of long edge parts 22a and 22b adjacent to the short edge parts 22c and 22d. That is, the respective swelling parts 22e are, as seen in Fig. 26, formed on the end parts of the slot 22 to which the waving belt 74 is concentrically gathered, for example, when the waving belt 74 is abruptly pulled or the like. The respective swelling parts 22e are formed in accordance with a cold-working by bending a part of the base member 20 to one surface side, moving the bent part to the other surface side and shaping it in a curved surface. Accordingly, the respective swelling parts 22e have the large quantity of swell from the base member 20 and are excellent in view of strength. The seat belt hanging and holding member 10 constructed as mentioned above is formed so as to form the base member 20 integrally with the coating member 30in accordance with an insert-molding similar to the sixth embodiment. In addition, for example, when the waving belt 74 is suddenly pulled or the like, the waving belt 74 may slip to one short edge part 22c side (or the other short edge part 22d side), as shown in Fig. 25, or concentrically come to one short edge part 22c side (or the other short edge part 22d side), as shown in Fig. 26. In this case, the force of the waving belt 74 is concentrically exerted on one short edge part 22c side. However, since the short edge parts 22c and 22d, and the end parts of the long edge parts 22a and 22b adjacent thereto are formed in the shape of a smoothly curved surface by providing the swelling parts 22e, an extremely small stress concentration is only produced in the coating member 30 coming into contact with these short edge parts 22c, 22d or the like. Therefore, if the force of the waving belt 74 concentrically gathers to, for example, one short edge part 22c side of the slot 22, the force applied to the coating member 30 from the one short edge 22c side will be distributed and not be concentrated to one part. Thus, the strength of the coating member 30 can be increased without increasing the thickness or strength of a resin. Further, since the contact area between the short edge parts 22c, 22d or the like and the coating member 30 is increased by providing the swelling parts 22e, a face pressure exerted on the coating member 30 from the short edge parts 22c, 22d or the like can be decreased. Therefore, with the above described matter taken into consideration, if the force of the waving belt 74 is concentrically gathered to the one short edge part 22c side, the force applied to the coating member 30 from the base member 20 can be softened. That is, the strength of the coating member 30 can be increased without increasing the thickness or strength of the resin. If the force of the waving belt 74 should concentrically gather to, for example, the one short edge part 22c side, so that the coating member 30 would be broken, the waving belt 74 would come into contact with the one short edge part 22c or the like and then it would not be broken thereby, since the one short edge part 22c or the like is formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 is folded back by forming the swelling part 22e. Besides, the seventh embodiment achieves similar operational effects to those of the sixth embodiment. Additionally stated, in the present embodiment, the position of the above described bending part L is, as seen in Figs. 24 to 26, a position evading the swelling parts 22e formed in the short edge parts 22c and 22d. Accordingly, when the base member 20 is bent by a prescribed angle with respect to the bending part L, it can be bent with a pressing force equal to that of the sixth embodiment. This is the case in other embodiments described above and below. Next, an third embodiment of the present invention will be described by referring to Fig. 27. Herein components common to those of the second embodiment seen in Figs. 24 to 26 are affixed by the same reference symbols as those in these figures and the explanation thereof will be omitted. The difference between the third embodiment and the second embodiment resides in that a swelling part 22e is provided throughout the entire periphery of a slot 22. Namely, in the slot 22, the swelling part 22e similar to that illustrated in Fig. 24B is formed on one surface side and the other surface side of the base member 20 throughout all the peripheries of the long edge parts 22a and 22b and the short edge parts 22c and 22d. According to the seat belt hanging member 10 constructed as described above, since the whole part of the slot 22 comes into smooth contact with the coating member 30, a stress concentration can be decreased in all the parts of the coating member 30 in contact with the slot 22. Further, since a face pressure can be lowered in all the parts where the slot 22 comes into contact with the coating member 22 by forming the swelling part 22e. Therefore, strength can be improved, because of reasons the same as those of the second embodiment, in all the parts of the coating member 30 along the slot 22. Additionally, if the coating member 30 should be broken, the waving belt 74 could be prevented from being damaged as a result of its abutting against the slot 22, since the whole part of the slot 22 is formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 is folded back. Besides, the third embodiment exhibits operational effects similar to those of the sixth and seventh embodiments. Now, referring to Fig. 28, a fourth embodiment of the present invention will be described hereinafter. Herein, components common to those of the second and third embodiments shown in Figs. 24 to 27 are affixed by the same reference numerals as those of the above embodiments and the explanation thereof will be omitted. The fourth embodiment is different from the second and third embodiments in that the end parts of the slot 22 in its longitudinal direction or the whole periphery of the slot 22 swell or expand to one surface side of the base member 20 and are formed in the shape of a smoothly curved surface along the direction in which the waving belt (seat belt) 74 is reflected. That is, the short edge parts 22c and 22d and the long edge parts 22a and 22b adjacent thereto, of the slot 22, or the whole periphery of the slot 22 are provided with the swelling parts 22e swelling merely to one surface side of the base member 20. The parts provided with the swelling parts 22e are formed so as to have smoothly curved surfaces along the direction in which the waving belt 74 is folded back. Further, the swelling parts 22e are formed in accordance with a cold-working by bending a part of the base member 20 to one surface side and shaping the bent part in a curved surface. Accordingly, the swelling parts 22e have the large quantity of swell from the base member 20 and are excellent in their strength. The seat belt hanging and holding member 10 constructed as mentioned above achieves operational effects similar to those of the first to third embodiments. Next, a fourth embodiment of the present invention will be described with reference to Figs. 29 to 30. Herein, components common to those of the sixth embodiment illustrated in Fig. 23 are affixed by the same reference symbols as those of Fig. 23 and the explanation thereof will be omitted. The fourth embodiment is different from the first embodiment in that the end parts in the longitudinal direction of the slot 22 are largely opened. Specifically state, the short edge parts 22c and 22d of the slot 22 are formed by circular arcs respectively having a diameter larger than the dimension between the long edge parts 22a and 22b. The short edge parts 22c and 22d maybe formed in the shape of an elliptically curved surface or in other shape with a curved surface. In this case, when the short edge parts are formed, for example, in the shape of an elliptically curved surface, the ellipse may be preferably disposed so as to be longitudianlly long in Fig. 29. In addition, the short edge parts 22c and 22d of the slot 22 and the long edge parts 22a and 22b adjacent thereto, or the whole periphery of the slot 22 are formed so as to be smoothly curved along the direction in which the waving belt 74 is reflected. In the case of the seat belt hanging and holding member 10 constructed as described above, the radius of curvature of the short edge parts 22c and 22d is increased, so that the stress concentration of the short edge parts 22c and 22d can be mitigated. Therefore, stress generated in the short edge parts 22c and 22d can be reduced and the strength of the base member 20 can be substantially improved. Additionally, since a space between the long edge parts 22a and 22b can be narrowed, the width of a part extending along the long edge part 22a, that is, the width of a part for supporting the waving belt 74 can be increased. Consequently, the strength of the short edge parts 22c and 22d can be improved relative to a force from the waving belt 74 and the part extending along the one long edge part 22a can be also improved. Further, since the short edge parts 22c and 22d of the slot 22 and the long edge parts 22a and 22b adjacent thereto, or the whole periphery of the slot 22 come into smooth contact with the coating member 30, stress concentration can be softened in all the parts of the coating member in contact with the slot 22. Accordingly, strength can be improved in all the parts of the coating member 30 along the slot 22, because of reasons similar to those of the seventh embodiment. If the coating member 30 should be broken, the waving belt 74 would be prevented from being damaged when the waving belt 74 abuts on the slot 22, since the slot 22 is formed in the shape of a smoothly curved surface along the direction in which the waving belt 74 is folded back. Besides, the fifth embodiment can realize other operational effects similar to those of the first and second embodiments. Now, an sixth embodiment of the present invention will be described below by referring to Fig. 31. Herein, components common to those of the fifth embodiment seen in Fig. 29 are affixed by the same reference symbols as those of the fifth embodiment and the explanation thereof will be omitted. The difference between the sixth embodiment and the fifth embodiment resides in that the swelling part 22e is provided along the one long edge part 22a of the slot 22. Specifically, the swelling part 22e as shown in Fig. 24A or 28 is provided in the long edge part 22a of the slot 22 in the side on which the waving belt 74 is folded back. In the next place, with reference to Fig. 32, a seventh embodiment of the invention will be described hereinafter. Herein, components common to those of the fifth embodiment shown in Fig. 29 are affixed by the same reference numerals as those of the tenth embodiment and the explanation thereof will be omitted. The seventh embodiment is different from the fifth embodiment in that the swelling parts 22e are provided in the short edge parts 22c and 22d of the slot 22 and the parts of the long edge parts 22a and 22b adjacent thereto. Further, the swelling parts 22e are formed with the material similar to that illustrated in Fig. 24A or Fig. 28. Now, viewing Fig. 33, a eighth embodiment of the present invention will be described in the following. Herein, components common to those of the fifth embodiment illustrated in Fig. 29 are affixed by the same reference symbols as those of the fifth embodiment and the explanation thereof will be omitted. The eighth embodiment is different from the fifth embodiment in that the swelling part 22e is provided throughout the whole periphery of the slot 22. Further, the swelling part 22e is formed with the member similar to that seen in Fig. 24A or Fig. 28. A ninth embodiment of the present invention will be now described by referring to Fig. 34. Herein, components common to the fifth embodiment shown in Fig. 29 are affixed by the same reference symbols as those of the tenth embodiment and the explanation thereof will be omitted. The difference between the ninth embodiment and the fifth embodiment resides in that reinforcing parts 22f are provided along the outside parts of the short edge parts 22c and22d of the slot 22. Specifically stated, the reinforcing parts 22f are, as shown in Fig. 35, formed so as to swell to one surface side of the seat belt holding part 20B. Further, the reinforcing parts 22f may be, as illustrated in Fig. 36, formed so as to swell or expand to one surface side and to the other surface side. The strength in the peripheries of the short edge parts 22c and 22d on the base member 20 can be improved by providing the reinforcing parts 22f. A tenth embodiment of the present invention will be next described with reference to Fig. 37A. Herein, components common to those of the fifth embodiment shown in Fig. 29 are affixed by the same reference numerals as those of the fifth embodiment and the explanation thereof will be omitted. The tenth embodiment is different from the fifth embodiment in that the reinforcing part 22f is provided along a part outside the one long edge part 22a of the slot 22. That is, the reinforcing part 22f illustrated in Fig. 35 or Fig. 36 is provided along a part in the lower side of the long edge part 22a of the slot 22on which the waving belt 74 is reflected. Thus, the strength of a part in the base member 20 for holding the waving belt 74 can be improved by the above described reinforcing member 22f. Although, in the first to tenth embodiments, the step part 24 is, as shown in Fig. 37B, formed substantially at right angles with the outer peripheral edge part 23, the step part 24 may be formed, as shown in Fig. 37C, so as to bite obliquely the inside of the outer peripheral edge part 23 or maybe formed, as shown in Fig. 37D, so as to be slantingly inclined to the coating member 30 side. In this case, in order to prevent a resin from leaking along the outer peripheral edge part 23, the step part 24 may be preferably formed, as illustrated in Fig. 37B, substantially at right angles with the outer peripheral edge part 23, or as illustrated in Fig. 37C, formed so as to bite obliquely the inside of the peripheral edge part 23. Further, although, in the first to tenth embodiments, the height of the step part 24 is set so that the surface of the coating member 30 is substantially flush with the surface of the outer peripheral edge part 23, the height of the step part 24 may be preferably set so that the surface of the outer peripheral edge part 23 is slightly higher than that of the coating member 30 in order to prevent the resin from leaking along the outer peripheral edge part 23. Additionally, it is desired to form the base member 20 shown in the first to tenth embodiments in accordance with a cold-working by using a high-tension steel. For the high-tension steel, the steel having chemical components shown in Table 1 may be preferably used. The test results of this high-tension steel are apparently shown in Table 2. The base member 20 is formed under a cold-working by using the above mentioned high-tension steel, so that the base member 20 whose finish accuracy and dimensional accuracy are considerably excellent can be obtained. Thus, when the base member 20 is inserted into a metal mold to be subjected to an insert-molding, an abnormal force due to the deflection of the base member 20 is not exerted on the metal mold from the base member 20. Accordingly, the duration of life of the metal mold can be improved. Further, the steel is work-hardened under a cold-working and a sufficient strength can be obtained, so that the thermal treatment is not needed. Thus, the number of production processes for the base member 20 can be decreased. Furthermore, since the base member is formed with the high-tension steel, there is no fear of hydrogen brittleness after a plating process, and therefore, the thermal treatment for removing the hydrogen brittleness is not required. Therefore, the number of production processes can be furthermore reduced and the cost can be lowered. Next, processes for cold-working the base member 20 by the use of the high-tension steel will be described with reference to Figs. 38 to 42. In this case, the base member 20 manufactured in accordance with the cold-working corresponds to the base member 20 shown in Fig. 24 and is provided with the swelling part 22e protruding merely to one side, as illustrated in Fig. 28. The part of the slot 22 which is not provided with the swelling part 22e is, as shown in Fig. 30, formed in the shape of a curved surface. The above mentioned base member 20 is, manufactured by a press machine set for automatically and continuously carrying out the operations of respective processes illustrated in Figs. 38 to 42. Initially, a high-tension steel plate S wound in the shape of a coil as a raw material of the base member 20 is fed one by one to the press machine while it is adjusted to a flat shape. Then, in the first process P1 (see Fig. 38), slits S1 are initially punched out to divide the respective base members 20 which are successively formed and positioning holes H1 are also punched out. At this time, marks such as required numeric characters, symbols, etc. are simultaneously pressed. Next, in the second process P2, lower holes S2 for forming the slots 22 are punched out. At this time, burs are produced in the side toward which the lower holes S2 are punched out. Then, in the third process P3, the angular parts of the side in which the burs of the lower holes S2 are produced are face-pressed so that the angular parts of the lower slots S2 are finished to be rounded. Thus, the burs produced in the second process are pressed inward so that they are apparently removed. Further, in the fourth process P4 (see Fig. 39), angular parts opposite to the above described burs of the lower slots S2 are face-pressed so that the angular parts are finished to be rounded. Thus, the lower slots S2 subjected to the third and fourth processes have their entire peripheries neatly finished so as to have a curved surface as illustrated in the long edge parts 22a and 22b of Fig. 30. Next, in the fifth process P5, parts corresponding to the short edge parts 22c and 22d of the slots 22 in the lower holes S2 are bent so that protruding parts S3 corresponding to swelling parts 22e are formed. At this time, the peripheral parts of the protruding parts S3 are slightly curved toward the direction to which the protruding parts S3 protrude. That is, the peripheral parts of the protruding parts S3 are formed in a distorted shape. Thus, in the sixth process P6 (see Fig. 40), the peripheral parts of the protruding parts S3 are formed so as to be flat. Thus, only the protruding parts S3 swell or expands from the flat high-tension steel plate S. At this time, the protruding parts S3 are simultaneously formed. Then, in the seventh process P7, a face pressing is made along the lower slots S2, so that the protruding parts S3 and other parts are finished in the shape of a smoothly curved surface. Thus, the protruding parts S3 are formed to become short edge parts 22c and 22d having the swelling parts 22e with curved surfaces as shown in Fig. 28 and other parts to become long edge parts 22a and 22b with curved surfaces as shown in Fig. 30. Then, in the eighth process P8, holes S4 are punched out for forming the adjacent upper side parts and lower side parts of the base members 20. Further, in the ninth process P9, required holes S5 are punched out. Next, in the tenth process P10, bolt inserting holes 21 are punched out and the outer peripheral edge parts 23 of the base members 20 are punched out. In this case, only connecting plates S6 for connecting the adjacent base members 20 together are left as they are. Then, in the eleventh process P11, the connecting plates S6 are cut from the adjacent base members 20, so that the individually separated base members 20 are completed. According to the manufacturing method of the base member 20 constructed as mentioned above, since the edge parts of the lower hole S2 are bent so that the swelling parts 22e are formed. Thus, the swelling parts 22e can largely protrude from the surface of the base member 20. Further, the swelling parts 22e and other parts can be neatly finished in the shape of a smoothly curved surface by face-pressing. Specifically , the edge parts of the slot 22 can be finely finished in the shape of a curved surface only by a press machine, so that a finish-working (a barrel polishing work) does not need to be done in another process. Therefore, the cost can be lowered. In addition, the quantity of swell of the swelling parts 22e can be 0.2 to 0.5 times as thick as the thickness of a base 2, as illustrated in Fig. 32. Therefore, the contact area between the slot 22 and the coating member 30can be increased, so that a face pressure exerted on the coating member 30 can be lowered. When the processes of Figs. 6 to 8 shown in the first example are carried out in addition to the fifth process P5 for forming the protruding parts S3, the swelling parts 22e respectively protruding to one and the other sides of the base member 20 can be formed. In other words, the swelling parts 22e shown in Fig. 24 can be formed. The quantity of swell of the respective swelling parts 22e produced in this case can reach 0.2 to 0.5 times as thick as the thickness of the base member 20. Further, also in the production processes shown in Figs. 2 to 8 and Figs. 17 to 19, the quantity of swell of the respective swelling parts 22e can reach 0.2 to 0.5 times as thick as the thickness of the base 2. With the invention according to claim 1, when the seat belt is in a state where it can be supplied, the seat belt can be slidingly supplied while the intermediate part of the seat belt is folded back on the coating member, for example, by pulling the seat belt. However, when the supply of the seatbelt is stopped, a force for pulling the seat belt is directly exerted on the coating member. The force directly applied to the coating member is directly exerted on the slot of the base member through the coating member. The coating member undergoes, as its reaction, a reaction force from the edge parts of the slot. However, since at least the edge part of the slot corresponding to a position on which the seat belt is folded back is formed in the shape of a smoothly curved surface along the direction in which the seat belt is folded back, the stress concentration of the coating member in contact with the edge part of the slot is extremely decreased. Consequently, even when a force acts on the coating member from the edge part of the slot, a large stress is not generated in the coating member and such a result can be obtained that a strength is substantially more increased than that of a conventional one. Accordingly, since the thickness of the coating member can be reduced in proportion to the increase of strength, the material cost of the coating member can be lowered without deteriorating a safety owing to the decrease of strength of the coating member. Thus, the cost can be lowered. Since the thickness of the coating member is set by employing an excessively sufficient safety factor, the coating member should not be broken. If the coating member should be broken, the seat belt would not be cut when it abuts on the edge part of the slot, since the edge part of the slot corresponding to a position on which the seat belt is folded back is formed in the shape of a curved surface. In other words, if the coating member is broken, a safety by the seat belt can be ensured. In addition, if the coating member should be damaged, the seat belt would not be cut. Therefore, a tinner coating member may be possibly formed. With the invention according to claim 7, since the step part set by one step lower than the outer peripheral edge part of the base member is provided in the boundary part between the outer peripheral edge part and the coating member, a resin can be prevented from leaking along the outer peripheral edge part of the base member from the boundary part during insert-molding. Accordingly, the burs formed with the coating member can be prevented from being produced in the boundary part between the outer peripheral edge part of the base member and the coating member. Further, since the leakage of the resin can be prevented, as described above, the closing force of the metal mold does not need to be strongly set in order to prevent the leakage of the resin. Thus, the durability of the metal mold can be improved. CHEMICAL COMPONENTS % (CAST ANALYSIS) C 0.15 OR LOWER Si 1.50 OR LOWER Mn 1.80 OR LOWER P 0.030 OR LOWER S 0.010 OR LOWER Al 0.080 OR LOWER AND OTHERS Cr

Claims: A seat belt hanging and holding member (10) for slidably hanging and holding a seat belt (74) by folding back an intermediate part of the seat belt ; said seat belt hanging and holding member comprising: a base member (20) made of a metal plate having a slot (22) into which said seat belt (74) is inserted; and a coating member (30) made of a synthetic resin for covering the periphery of the slot (22) of the base member (20) and having a seat belt inserting hole formed on a part corresponding to said slot; characterized in that the seat belt hanging and holding member (10) further comprises outer peripheral edge parts (23) of the base member (20), said outer peripheral edge parts (23) are provided with a step part (24) set lower by one step than said outer peripheral edge part in boundary parts (23a) between the edge parts (23) and said coating member (30), so as to have a height that the surface of the coating member (30) is substantially flush with the surface of the outer peripheral edge part (23). A seat belt hanging and holding member (10) according to claim 1, characterized in that said slot (22) has an edge part (22a) corresponding to at least the folded-back part of the seat belt (74), said slot (22) is formed in a curved-surface shape smoothly curved along the direction in which the seat belt is folded back; and in that the edge part (22a) of the slot corresponding to at least the folded-back part of the seat belt (74) swells to at least one surface side of the base member and is formed in a smoothly curved surface along the direction in which the seat belt is folded back. A seat belt hanging and holding member according to claim 1 or 2, characterized in that the edge part (22a) of the slot (22) corresponding to at least the folded-back part of the seat belt swells to one surface side and the other surface side of the base member and is formed in a smoothly curved surface along the direction in which the seat belt is folded back. A seat belt hanging and holding member (10) according to claim 1, characterized in that the end part (22c, 22d) of said slot in its longitudinal direction is formed in a smoothly curved surface along the direction in which the seat belt is reflected; and in that the end part (22c, 22d) of the slot in its longitudinal direction swells to at least one surface side of the base member. A seat belt hanging and holding member according to claim 4, characterized in that the end part of the slot in its longitudinal direction expands to one surface side and to the other surface side of the base member and is formed in a smoothly curved surface along the direction in which the seat belt is folded back. A seat belt hanging and holding member according to any one of the preceding claims, characterized in that the base member is formed by cold-working a raw material of high-tension steel.

Inventors: ITO TADAO, ITO, TADAO
Applicants: ENSHU CO LTD, ENSHU CO., LTD.
Application year: 1996
Main classification: B60R22
IPC codes: B60R22