Shift Knob

Abstract: A shift knob comprises a pair of leather pieces (10a) stitched together at their margins (10b) to form a covering body (10); a resin-formed body (11) inserted into the covering body with a predetermined gap; and a resin (12) injected into the gap.

Description: The invention relates to a method of manufacturing a shift knob having a leather-made covering body over its outer surfaces. The shift knob of an automatic transmission of an automobile is formed by applying a covering body made of leather over the outer surfaces of a resin-formed body as disclosed in DE-A-36 01 474. This prior art method of manufacturing a shift knob comprising the steps of forming a leather covering body, accomodating said covering body within a cavity of the upper half of an injection mold, inserting a body as the other half of the mold into said covering body with a predetermined gap, and injecting a resin into said gap to form the shift knob through injection molding. DE-A-2252391 discloses a shift knob comprising an inner rigid body made of resin and a layer of formed resin injected over said body. By means of this the shift knob is integrally formed having a core member made from the formed resin. In another conventional shift knob as shown in Figures 5 and 6, the outer surfaces of a resin-made body 1 are covered with a plurality of leather pieces 2a, and these leather pieces 2a are stiched (the seams are indicated by 2b) to form a covering body 2. At insertion holes 5, 6 into which a detent button 3 and an overdrive switch 4 are inserted, respectively, the leather pieces 2a are folded back into the respective insertion holes 5, 6, and bezels 7, 8 are attached so as to be interposed between the leather piece and the button 3 and between the leather piece and the switch 4, respectively, so that the leather pieces 2a will be tightly fitted and not be loosened out. The above construction addresses the following problems. The covering body 2 must be prepared by stitching the leather pieces 2a with the outer surfaces of the resin-made body 1 covered with the pieces, and this entails a cumbersome and time-consuming stitching operation. Also, the bezels 7, 8 must be inserted into the insertion holes 5, 6, which further complicates the overall fabrication process. Further, since the leather pieces 2a must be stiched while covering the resin-formed body 1, the technique of stiching them is so limited as to produce analogous designs. Furthermore, the bezels 7, 8 are required at the portions into which the detent button 3 and the overdrive switch 4 are inserted to prevent the loosening out of the leather pieces 2a, and this increases the number of parts involved in the fabrication. Accordingly, it is the object of the invention to provide a method of manufacturing a shift knob which can be performed easily and allows not only diversification in design but also reduction in the number of parts. This object is solved by the features as claimed in claim 1. A shift knob which comprises a bag-like covering body being formed by stiching leather pieces and a resin-formed body being formed inside the covering body by injection. The shift knob has the bag-like covering body formed in advance by stiching the leather pieces together. Therefore, the stiching is not only easy but also free from restrictions, allowing many designs to be produced. In addition, the resin-formed body is prepared by injection, and this contributes to improving the contact between the covering body and the resin-formed body and thereby dispensing with the bezels. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal sectional view of the entire device of present invention; Figure 2 is a perspective view thereof; Figure 3 is a diagram showing a fabrication process; Figure 4 is a sectional view showing the right half of a detent button; and Figure 5 is a longitudinal sectional view of a conventional device; and Figure 6 is a perspective view of the conventional device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the device will be described with reference to Figures 1 through 4. In Figures 1 and 2, reference numeral 10 designates a covering body, which is formed into a bag-like profile by stitching, e.g., three pieces 10a of leather (genuine and/or artificial) together (the seams are indicated by 10b). Reference numeral 11 designates an inserting resin-formed body, and in the middle thereof is an opening 11a into which a not shown shift lever of an automatic transmission system is to be inserted. A resin-formed body 12 made of an elastic resin such as urethane resin is injected between the inserting resin-formed body 11 and the covering body 10 to form a shift knob 13. At an insertion hole 14 formed on a side surface of the shift knob 13 is a detent button 15 which is to be mounted by being inserted thereinto, while at an insertion hole 16 formed at a back surface thereof is an overdrive switch 17 similarly mounted. A process of fabricating such shift knob will be described next. First, the three pieces of leather 10a are overlapped in pairs and are stitched together at their margins (the seams are indicated by 10b). By reversing the stitched pieces so that their seams come inside, the bag-like covering body 10 is formed. The covering body 10 is accommodated within a cavity 18a formed by a pair of molds 18 as shown Fig. 3. Then, a hole 11a of an inserting resin-formed body 11 is fitted with an inner mold 19 having a resin injection hole 19a, and the inner mold 19 is set within the cavity 18a of the mold 18 to locate the inserting resin-formed body 11 inside the covering body 10. Further, a slide core 20 is inserted into the insertion hole 14 thereby to cause a part of the covering body 10 to be brought into pressure contact with the inner surfaces of the insertion hole 14. At this stage, when urethane resin is injected into the resin injection hole 19a of the inner mold 19, the urethane resin is injected between the inserting resin-formed body 11 and the covering body 10 through the hole 11b of the inserting resin-formed body 11, causing the covering body 10 to be brought into pressure contact with the inner surface of the cavity 18a while discharging air in the cavity 18a from a not shown air outlet. When the injected urethane resin is solidified afterwards, a resin-formed body 12 is formed. As shown in Figure 4, the detent button 15 is also formed by inserting a resin-formed body 15b into a cylindrically shaped covering body 15a made of leather. According to the thus constructed shift knob, the following advantages can be obtained. The covering body 10 can be formed by stitching the leather pieces 10a in advance as "parts". Thus, unlike the conventional covering body which is formed by stitching the leather pieces 2a with the leather pieces covering over the outer surfaces of the resin-formed body 1, the stitching operation involved in the device is easy, allowing the stitching time to be reduced. Further, as described before, since the covering body 10 may be stitched to be bag-like in advance, restrictions such as the number of leather pieces 10a and the stitching mode may be eliminated, thereby allowing a diversity of designs to be produced. Furthermore, since the resin-formed body 12 is prepared by injecting the urethane resin into the covering body 10 and solidifying it therein, the contact between the covering body 10 and the resin-formed body 12 is satisfactory, thereby preventing the covering body 10 from being unfitted from the resin-formed body. Thus, it dispenses with the attaching of the bezels to the insertion holes 14, 16, which contributes to reducing the number of parts. The stitching operation is made easy and less time-consuming, as well as the use of bezels can be dispensed with, which all contribute to facilitating the fabrication of the shift knob 13. Moreover, a predetermined pattern, mark or the like is carved into the cavity so that the pattern is easily copied in the surface of the leather pieces. Therefore, the shift knob having a good design is easily manufactured. The shift knob of the device is formed by stitching the leather pieces to prepare a bag-like covering body and injecting a resin into such covering body to form a resin formed body. Therefore, the advantages such as easy fabrication, diversified designs, and reduction in parts owing to the elimination of bezels can be obtained.

Claims: A method of manufacturing a shift knob (13) comprising the steps of: stitching at least two pieces of leather (10a) together at their margins (10b) to form a covering body (10); accomodating said covering body (10) within a cavity (18a) of a mold (18); inserting a resin-formed body (11) comprising holes as injecting channels (11a,11b) into said covering body (10) with a predetermined gap; and injecting a resin through said injecting channels (11a,11b) into said gap to form said shift knob (13) as an integral member comprising said resin-formed body (11), said injected resin and said covering body (10). A method of manufacturing a shift knob (13) as claimed in claim 1, wherein said covering body (10) is reversed to position a stiched portion of said leather to an inner side of said covering body (10). A method of manufacturing a shift knob (13) as claimed in claim 1, wherein said resin is an elastic resin. A method of manufactuing a shift knob (13) as claimed in claim 1, wherein said inserted resin body (11) has a hole (15) for mounting a switch therein. A method of manufacturing a shift knob (13) as claimed in claim 1, wherein a pattern is carved into an inner surface of the mold (18).

Inventors: AMANO TOKUHIRO C O K K TOKAI R, KATO HIROYUKI C O K K TOKAI RI, AMANO, TOKUHIRO, C/O K.K. TOKAI RIKA DENKI, KATO, HIROYUKI, C/O K.K. TOKAI RIKA DENKI
Applicants: TOKAI RIKA CO LTD, KABUSHIKI KAISHA TOKAI RIKA DENKI SEISAKUSHO
Application year: 1991
Main classification: B60K20
IPC codes: G05G1, F16H59, F16H61, B60K20, B29C45