Steering Unit

The present invention relates to an improved steering unit for a boat, and more particularly to an improvement in a steering unit which includes an inner cable disposed within a push-pull control cable, one end thereof being secured to an outer peripheral surface of a disc rotatably mounted in a housing.

One of the steering units of this type, as are known in the art, is so constructed that a bend portion 18 of an end fitting 20 fitted to one end of an inner cable 4 is fixedly engaged in a hole provided in a disc and extending in the axial direction as shown in FIG. 1, and a helm or an outboard engine (hereinafter referred to as "a helm means") which is connected to the other end of the inner cable 4 is operated by pushing and pulling operations caused by the rotational movement of the disc. In general, a steering unit is subjected to considerable shock by repeated waves striking the helm means. Therefore, a corner 19 of the bend portion 18 will be fatigued from the repeated pushing and pulling operations of the inner cable 4 finally resulting in breakage at the corner 19. Thus, there is a fatal disadvantage in the conventional steering unit. Further, there are often generated cracks in the corner 19 during the bending process of the end fitting 20. These cracks are often invisible. Therefore, the above hazard cannot be eliminated readily.

An object of the present invention is to provide a new steering unit which can reliably perform a steering function safely for a long period of time even when the helm means is subjected to considerable shock as a result of being struck repeatedly by waves.

Other objects of the invention will become apparent from the following description given with reference to the accompanying drawings.

FIG. 1 is a plan view showing the structure of an end portion of an inner cable employed in the conventional steering unit;

FIG. 2 is a partially cutaway plan view showing the main parts of an embodiment of the present invention;

FIG. 3 is an enlarged plan view showing the main parts of the embodiment of FIG. 2;

FIG. 4 is a sectional view taken on line X--X of FIG. 2; and

FIG. 5 is a partially cutaway and enlarged front view showing the structure of an end fitting of an inner cable employed in the embodiment of FIG. 2.

Referring to FIG. 2, numerals 1 and 2 designate a housing and a push-pull control cable (hereinafter referred to as "a control cable"), respectively. The control cable 2 comprises an inner cable 4 having a resistance against the push-pull loads and a flexible conduit 3 having elasticity in which the inner cable 4 is slidably disposed. A taping 4a made of, for instance, polyvinyl chroride, may be circumferentially arranged around the core element 46. A disc 5 has an inner teeth 5a in mesh with a pinion 7 and is rotatably mounted in the housing 1 by a shaft 6. The inner cable 4 is wound in a groove 8 formed in an outer peripheral surface of the disc 5 and secured by means of an end fitting 9 made of metal to a suitable part of the disc 5.

As shown in FIGS. 3 and 5, the end of the inner cable 4 is secured to a leg portion 9a of the end fitting 9. The end fitting 9 has a head portion 9b extending from the leg portion 9a via inclined portion 9c the inclination of which is small. The head portion 9b may be flat, if desired, and is provided at the center thereof with a hole 10. A concave portion 11 is formed at a suitable part of an outer peripheral surface of the disc 5. The head portion 9b of the end fitting 9 can be so engaged in the concave portion 11 that there is no play at least in the axial direction of the inner cable 4. The end fitting 9 is secured to the disc 5 by a bolt 12 and/or a nut 13 and split pin 14.

As shown in FIG. 4, an unguent 15 made of synthetic resin such as polyamides in order to reduce sliding friction is engaged to an inner surface 1a of the housing 1. The unguent 15 has a groove 16 in which the inner cable 4 can slide, by which sliding friction of the inner cable 4 in winding up is reduced to a minimum.

The advantages and operations of the present invention will become apparent from the following description.

When the disc 5 is rotated in the direction of A or B by the rotation of the pinion 7, the inner cable 4 secured at one end thereof to the disc 5 is operated in the direction of C or D to operate the helm means (not shown) connected to the other end of the inner cable 4. In that case, the helm means is subjected to a great shock caused by waves repeatedly. Therefore, the inner cable 4 gets the pushing and pulling loads (in the direction of C or D) thereon. The load is transmitted through the curved portion of the inner cable 4 disposed between the disc 5 and the unguent 15, to the end fitting 9. The inner cable 4 can withstand such a load since the head portion 9b of the end fitting 9 is so secured to the concave 11 that there is no play. Further, the inner cable 4 is never cut off at the end fitting 9 since the inclined portion or curved portion 9c has no cracks due to the inclination being small. Therefore, the steering unit of the present invention can perform steering function safely and reliably for a long period of time.

As shown in FIG. 5, fitting of the end portion of the inner cable 4 to the end fitting 9 is conducted by die casting against the end portion of a core element 4b of inner cable 4 in which a prescribed length of a taping 4a is stripped, or by caulking of the end fitting 9. In order to obtain a strong fitting, the end portion of the core element 4b may be provided with an enlarged part 17. Further, a metal fitting instead of the enlarged part 17 may be secured by means of caulking or welding to the end portion 4b of the inner cable 4. In addition, the end portion of the core element 4b of the inner cable 4 may be swaged without stripping the taping 4a, to which the end fitting 9 is secured.

As above-mentioned, in the steering unit of the present invention, the connection of the disc with the end portion of the inner cable is very strong and the end fitting is never cut off. Therefore, the steering unit of the present invention can safely and reliably perform a steering function for a long period of time.

it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts set forth in the above general description or illustrated in the accompanying drawings since the invention is capable of other embodiment and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not limitation.