Abstract:
A link connecting structure includes a first and a second link member, a pin disposed between the two link members and having a tapered portion which engages with a complementary tapered hole in the second link member, and a resilient member for always urging the first link member in the direction of the second link member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to a link connecting structure and more particularly to a link connecting structure which can be used in any connecting structure where tight connection is needed such as for example in a link mechanism of a tilt steering apparatus. 
     2. Statement of the Prior Art 
     In a conventional link connecting structure shown in FIG. 4, a pin 7 is embedded in a first link member 3. The pin 7 is provided with a tapered portion 7a at the outer peripheral surface and a threaded portion 7b at the bottom portion thereof as viewed in the drawing. A second link member 4 is connected to the first link member 3 by the pin 7 through a ring 13 which is inserted into an engaging hole 11 on the second link member 4. In more detail, the ring 13 is provided with a tapered inner peripheral surface which is complementary to the tapered portion 7a of the pin 7 to be fittedly engaged with each other. A washer plate 12 and a rubber ring are disposed between the ring 13 and a nut 9 which is threadedly engaged with the threaded portion 7b of the pin 7 thereby to connect the first and second link members 3 and 4. This conventional structure has a drawback that each axial center of the hole 11, ring 13 and pin 7 may be off center, which leads to a disalignment of the link structure. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to provide an improved link connecting structure which can obviate the above conventional drawbacks. 
     It is another object of the present invention to provide an improved link connecting structure which is suitable for use in a connecting structure which needs a tight link connection. 
     Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
     To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the link connecting structure comprises a connecting pin for connecting a first and second link, the first link being received by the pin at one end of the pin and the second link being received by the pin at a tapered section of the pin. Additionally, a resilient member is arranged on the second link and a cover member is arranged next to the resilient member so that the resilient member urges the second link toward the first link. 
     The accompanying drawings which are incorporated in and constitute a part of this specification, illustrate two embodiments of the invention, and together with the description, serve to explain the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view, partly in cross-section, of a link connecting structure according to a preferred embodiment of the present invention; 
     FIG. 2 is a side view, partly in cross-section, of a link connecting structure according to another preferred embodiment of the present invention. 
     FIG. 3 shows the first embodiment of the present invention used in a tilt steering apparatus of a vehicle as well as a modified version of this embodiment; and 
     FIG. 4 is a view similar to FIG. 1 but showing a conventional link connecting structure. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, particularly in FIG. 1, a pin 7 is secured to a first link member 3. The pin 7 is provided with a conical tapered outer surface 7a and is provided with a screwed portion 7b at its top portion. A second link member 4 is provided with a tapered hole 4a in which the tapered portion 7a of the pin 7 is inserted. An O-ring 5 is disposed on the pin 7 between the second link 4 and a plate member 6 which is also disposed on the pin 7 at a stepped portion or shoulder 7c of the pin 7. A nut member 9 is threaded into the screwed portion 7b of the pin 7 to connect the two link members 3 and 4. The plate member 6 has a bent portion 6a for securing the O-ring in place. As shown in FIG. 1, the O-ring 5 forces the second link member 4 in the direction of the first link member 3 to always tighten the engagement between the two tapered portions 4a and 7a of the second link member 4 and the pin 7, respectively. When an exterior force is applied to the second link member 4, a force corresponding to the division force of the tapered portion is exerted upon the second member 4 in the direction illustrated with an arrow in the drawing. Such force is absorbed by the O-ring. The elastic deformation of the O-ring 5 is stopped by the bent portion of the plate member 6. Further, a large displacement of the second link member 4 due to a larger force applied thereto can be prevented by the contact of the link 4 with the top end 6b of the plate member 6. 
     Instead of using an O-ring, a dish spring may be used as illustrated in FIG. 2. In the drawing, dish spring 5&#39; is disposed between the link member 4 and plate member 6. 
     Referring to FIG. 3, there is illustrated an example of the invention used in a vehicle tilt steering apparatus. Gear 1 is secured to a screw member 2 which, in turn, is engaged with a nut member 3 corresponding to the first link member in FIG. 1. The gear 1 is connected to a motor or driving means (not shown) of the tilt steering apparatus. The engagement between the screw member 2 and nut member 3 is such that the rotational movement of the screw member is converted into the linear movement of the nut member 3 along the axis of the screw member 2. The pin 7 is secured to the nut member 3 and has a tapered portion 7a which is inserted into the hole 4a of the second link member 4 and a threaded portion 7b which is to be in threaded engagement with nut 9 through O-ring 5 and plate member 6, as is also shown in FIG. 1. The nut 9 secures the plate member 6 against a stepped portion or shoulder 7c of the pin 7. Thus the linear movement of the nut member 3 is transmitted to the second link member 4 through the pin 7 without causing a loose fitting or play therebetween. 
     This drawing also shows another possibility of using the invention, wherein the second link member 4 has another pin 17 which connects a third link member 8 to secure link connection therewith. The pin 17 has a tapered portion 17a which is inserted into a tapered hole 8a provided in the third link plate 8 and a threaded portion 17b which is threaded with nut 19 through link member 4, spacer member 10 and an O-ring 15 which is disposed within an annular groove 10a. 
     Thus, according to the present invention, plate member 6 of the spacer member 10 may be used to limit the displacement amount of the link members by properly defining the distance between the peripheral portions of the plate and spacer member and the link members. The O-ring or the dish spring may not be deformed beyond the elastic characteristics thereof. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the link connecting structure of the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.