Frame component for a belt winder and method for producing same

Abstract

The invention describes a method of manufacturing a substantially plate-shaped frame member (10) of a belt retractor including locking teeth (18). A plate-shaped element (24) is provided, wherein said element is plastically reshaped in portions so that a portion (28) thickened into a main portion (12) of the plate-shaped element (24) is formed. Furthermore, locking teeth (18) are produced in the thickened portion (28) so that the locking teeth (18) have a larger thickness than the plate-shaped element (24) prior to reshaping. Moreover, a frame member (10) for a belt retractor is described.

Claims

1. A method of manufacturing a substantially plate-shaped frame member (10) of a belt retractor including locking teeth (18), comprising the following steps of: a) providing a plate-shaped element (24) having oppositely facing first and second surfaces, b) plastically reshaping said plate-shaped element (24) in portions so that a portion (28) thickened into a main portion (12) of the plate-shaped element (24) is formed, the thickened portion (28) having a thickness (d) that is greater than a thickness (D) of non-plastically reshaped portions of the plate-shaped element (24), the thicknesses (d, D) of the thickened portion (28) and the non-plastically reshaped portions extending in a direction perpendicular to the first and second surfaces of the plate-shaped element (24) from the first surface to the oppositely facing second surface, and c) producing locking teeth (18) in said thickened portion (28) so that the locking teeth (18) have a larger thickness (d) than the thickness of the non-plastically reshaped portions of the plate-shaped element (24), the thickness (d) of the locking teeth (18) being equal to the thickness (d) of the thickened portion (28) so that the thickness of the locking teeth extends from the first surface of the plate-shaped member (24) to the oppositely facing second surface of the plate-shaped member.

2. The method according to claim 1, wherein that in step b) the plate-shaped element (24) is drawn and subsequently upset or pressed in the drawn portion so as to produce a chamfer (20).

3. The method according to claim 2, wherein after the plate-shaped element (24) is drawn, an opening (14) is produced in the plate-shaped element (24) adjacent to the thickened portion (28), with the locking teeth (18) being formed on a rim (16) of the produced opening (14).

4. The method according to claim 3, wherein after upsetting the plate-shaped element (24), the rim (16) of the opening (14) is trimmed.

5. The method according to claim 3, wherein the thickened portion (28) is formed to extend only over a partial periphery of the rim (16) of the opening (14), the locking teeth (18) being produced in the thickened portion (28) to extend only over a partial periphery of the rim (16) of the opening (14).

6. The method according to claim 2, wherein upsetting is carried out by means of a punching die (36) which acts primarily on the thickened portion (28).

7. The method according to claim 1, wherein the plate-shaped element (24) includes an opening (14), a rim portion (32) of the opening (14) being reshaped in step b) such that the thickened portion (28) projects substantially perpendicularly from the main portion (12).

8. The method according to claim 7, wherein after the plate-shaped element (24) is drawn, an outer radius (R2) of the thickened portion (28) is reduced by pressing in the thickened portion (28) from a rim portion (32) of the opening (14) to the adjacent main portion (12).

9. The method according to claim 1, wherein after step b), the thickened portion (28) exhibits a width (b) which is larger than the thickness (D) of the plate-shaped element (24) prior to reshaping.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and characteristics of the invention will be evident from the description that follows and the drawings which will be referred to and in which:

(2) FIG. 1 shows a frame member for a belt retractor according to the state of the art,

(3) FIG. 2 shows a frame member for a belt retractor according to the invention,

(4) FIGS. 3a to 3e show method steps according to the invention for manufacturing a frame member of a belt retractor according to a first variant, and

(5) FIGS. 4a to 4g show method steps for manufacturing a frame member of a belt retractor according to a second variant.

DESCRIPTION

(6) FIG. 1 illustrates a frame member 10 for a seat belt retractor according to the state of the art. The frame member 10 consists of a plate-shaped main portion 12 in which an opening 14 is provided. The opening 14 includes a peripheral rim 16 on which locking teeth 18 are formed in portions. The thickness d of the locking teeth 18 corresponds to the thickness D of the main portion 12 and of the entire frame member 10.

(7) In FIG. 2 a frame member 10 according to the invention is illustrated which has been manufactured by means of a method according to the invention. In FIGS. 3a to 3e and 4a to 4g two exemplary methods of manufacturing such frame member 10 are shown.

(8) The frame member 10 includes, analogously to the frame member 10 known from the state of the art, a planar main portion 12 as well as an opening 14 including a peripheral rim 16 on which at least in portions locking teeth 18 are provided. The frame member 10 has a substantially plate-shaped design.

(9) In contrast to the frame member 10 known from the state of the art, the locking teeth 18 are formed on a thickening 20 of the frame member 10, however, which is formed in one piece with the residual frame member 10 and the main portion 12. In this way a larger contact face 22 of the locking teeth 18 is resulting as compared to the locking teeth 18 known from the state of the art. The larger contact face 22 entails a reduction of the surface pressure of the locking teeth 18 and of counter teeth or a ratchet not shown. The thickness d of the locking teeth 18 is larger than the thickness D of the main portion 12 or the residual frame member 10 by at least 10%, especially by at least 20%.

(10) From FIG. 2 one can further infer that the locking teeth 18 extend only over a part of the rim 16, i.e. a partial periphery, wherein said part corresponds to the thickening 20. Thus the frame member 10 is configured in a material-saving manner despite the thickening 20 and a simultaneously enlarged contact face 22 of the locking teeth 18.

(11) In FIGS. 3a to 3e method steps of an exemplary manufacturing process are illustrated by which the frame member 10 including the thickening 20 is manufactured. All of FIGS. 3a to 3e in cross-section show a cutout of a plate-shaped element 24 which serves as a starting material for the frame member 10 and is reshaped into the frame member 10 illustrated in FIG. 2.

(12) In FIG. 3a the plate-shaped element 24 is illustrated in its initial condition. The plate-shaped element 24 has the thickness D which the later main portion 12 exhibits (FIG. 2). In addition, the plate-shaped element 24 is typically formed as a sheet metal member, for example a steel sheet member.

(13) In a first method step the plate-shaped element 24 is drawn so that after drawing it includes a first part 26, a transitional area or thickened portion 28 as well as a second part 30 (FIG. 3b), the second part 30 being drawn out of the main portion 12. In this way, the two parts 26, 30 are generally provided on two different levels and are interconnected by the thickened portion 28. The thickened portion 28 already partially corresponds to the thickening 20 of the finished frame member 10 (cf. FIG. 2). In total, the plate-shaped element 24 is S or Z shaped in cross-section after drawing in the transitional area of the parts 26, 30.

(14) After drawing the plate-shaped element 24 and forming the thickened portion 28 associated therewith the opening 14 is produced in the substantially plate-shaped element 24 (FIG. 3c). This may be performed by punching, for example. The opening 14 is configured in the second part 30 in the vicinity of the thickened portion 28, wherein the opening 14 almost completely cuts out the second part 30. Merely a projection 31 constituting a remainder of the second part 30 is retained which is later required partially for forming the thickening 20.

(15) The second part 30 therefore preferably includes a surface which substantially corresponds to that of the later opening 14 within the frame member 10 (FIG. 2).

(16) The opening 14 exhibits toward the plate-shaped element 24 the rim 16 over which the element 24 may be subsequently upset or pressed in a simple manner so as to form the thickening 20 from the thickened portion 28 and a major part of the projection 31 (FIG. 3d).

(17) After that, the element 24 is trimmed in the area of the rim 16 so that the final shape is resulting (FIG. 3e). Upon trimming the thickened portion 28 is trimmed partially and the residual projection 31 is trimmed completely so that a straight rim 16 is resulting.

(18) Upon trimming furthermore the teeth of the locking teeth 18 may be formed and the contact faces 22 thereof which a ratchet or counter teeth can contact as fully as possible may be cut to be planar.

(19) By plastically reshaping by means of drawing and upsetting or pressing the plate-shaped element 24 the thickening 20 is moreover formed over a width b which is larger than the thickness D of the element 24 prior to reshaping.

(20) By the method steps shown in FIGS. 3a to 3e a frame member 10 including the locking teeth 18 formed at the thickening 20 has been manufactured from the plate-shaped element 24 shown in FIG. 3a.

(21) The FIGS. 4a to 4g illustrate an alternative method of manufacturing the frame member 10, wherein in FIGS. 4a to 4g a plate-shaped element 24 is shown in cross-section which is reshaped into the frame member 10 including the thickening 20 as shown in FIG. 2.

(22) In FIG. 4a the plate-shaped element 24 is illustrated in the initial condition, the plate-shaped element 24 already including the opening 14 which has a rim portion 32. The plate-shaped element 24 may equally be a sheet metal part, especially a steel sheet part.

(23) In a first method step, the rim portion 32 is bent so that it projects perpendicularly from the residual plate-shaped element 24 or the later main portion 12 (FIG. 4b). The reshaped rim portion 32 forms a chamfer which at the same time constitutes the thickened portion 28. The thickened portion 28 corresponds to part of the later thickening 20.

(24) By chamfering or reshaping the rim portion 32 an inner radius and an outer radius R1, R2 are resulting in the transitional area from the part of the element 24 which has not been reshaped to the thickened portion 28. The inner radius R1 is formed on the side of the element 24 facing the opening 14, whereas the outer radius R2 is formed on the opposite side of the element 24.

(25) In a further method step the outer radius R2 is reduced at the thickened portion 28 in the transitional area from the reshaped rim portion 32 to the main portion 12 by upsetting and appropriate tools, for example, so that an approximately right angle is formed (FIG. 4c). In this way a folding edge 33 is formed around which the chamfered or drawn rim portion 32 later can be easily folded.

(26) After forming the reshaped rim portion 32 and reducing the outer radius R2, the thickening 20 is made in that the element 24 including the reshaped rim portion 32 is inserted in a tool 34 including a pressing plate or a punching die 36 as well as a locating surface 38 (FIG. 4d). The punching die 36 is configured so that it includes recesses 40 which are provided for the thickened portion 28 and, resp., the reshaped rim portion 32 (FIG. 4e).

(27) The element 24 rests on the locating surface 38 so that when a predetermined pressure is exerted the reshaped rim portion 32 is upset or pressed so that the latter is reshaped around the folding edge 33 facing away from the opening 14 (FIG. 4f). The pressing operation may be impact extrusion, for example, so that a thickening 20 integrally formed of at least two portions is resulting.

(28) After reshaping the rim portion 32 by means of the tool 34 the plate-shaped element 24 is reshaped such that it includes the thickening 20 having the thickness d and the width b (FIG. 4g). The thickening 20 includes the rim 16 on which the locking teeth 18 have been formed so that in total locking teeth 18 having a larger contact face 22 are resulting, as is illustrated in the frame member 10 in FIG. 2.

(29) In the illustrated embodiments the width b is larger than the thickness D.