Propeller Assembly for Marine Engine

1. Field of the Invention

The present invention relates to a propeller assembly, and more particularly to a propeller assembly for a marine engine.

2. Description of the Prior Art

A typical marine propeller assembly is disclosed in U.S. Pat. No. 5,252,028 to LoBosco et al. and comprises a propeller housing to be secured to a propeller shaft and to be rotated by the propeller shaft. However, the retainer disc may not solidly secure the propeller housing in place such that the propeller housing may be disengaged from the propeller shaft inadvertently and such that the marine propeller assembly may easily become failure.

The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional marine propeller assemblies.

The primary objective of the present invention is to provide a propeller assembly which may be solidly secured to the propeller shaft and which may be prevented from being disengaged from the propeller shaft inadvertently.

In accordance with one aspect of the invention, there is provided a propeller assembly for a marine engine, the propeller assembly comprises a propeller shaft rotatably supported in the marine engine and including an externally splined portion and an externally threaded outer end portion, a locking nut for engaging with the externally threaded outer end portion of the propeller shaft, a hub including at least three angularly spaced and axially extending keys each having a narrower outer end and a wider inner end, a central tube secured in the hub and rotated in concert with the hub, the central tube including a splined inner bore for receiving and mating with the externally splined portion of the propeller shaft and for allowing the hub to be rotated in concert with the propeller shaft, a tubular propeller housing including at least three angularly spaced outer propeller blades and including an inner peripheral surface having at least three pairs of lobes extended radially inward from the inner peripheral surface for forming and defining at least three keyways and for engaging with the keys of the hub, the lobes each including an outer end, the keyways each including a narrower outer end for engaging with the narrower outer end of the key and each including a wider inner end for engaging with the wider inner end of the key and for preventing the keys from being disengaged from the tubular propeller housing, the tubular propeller housing including at least three stops extended radially inward from the inner peripheral surface of the tubular propeller housing, the stops each including an outer end flush with the outer ends of the lobes, a retainer disc including a splined bore for engaging with and for mating with the externally splined portion of the propeller shaft, the retainer disc including a plurality of angularly spaced ears for engaging with the outer ends of the lobes and for engaging with the outer ends of the stops and for preventing the lobes and the stops from passing the ears of the retainer disc and for preventing the propeller housing from being disengaged from the propeller shaft, and a washer engaged between the retainer disc and the locking nut for preventing the locking nut from being rotated by the tubular propeller housing.

The stops include a number equals to that of the ears, a distance between any two adjacent stops is greater than a distance between any two adjacent ears for preventing the stops from moving beyond the ears and for preventing the tubular propeller housing from being disengaged from the retainer disc.

Further objectives and advantages of the present invention will become apparent from a careful reading of a detailed description provided hereinbelow, with appropriate reference to accompanying drawings.

FIG. 1 is an exploded view of a propeller assembly in accordance with the present invention;

FIG. 2 is a partial side view of the propeller assembly, in which a portion of the propeller housing is cut off for showing the interior structure of the propeller assembly; and

FIG. 3 is an end view of the propeller assembly illustrating the operation of the propeller assembly.

Referring to the drawings, and initially to FIGS. 1 and 2, a propeller assembly in accordance with the present invention is provided for a marine engine 90 and comprises a rotatable propeller shaft 7 rotatably supported in the marine engine 90. The propeller shaft 7 includes an externally splined portion 70 and includes an externally threaded outer end portion 71 for engaging with a locking nut 60. A hub 30 includes three or more angularly spaced and axially extending keys 33 each having a narrower outer end 332 and a wider inner end 334. A central tube 31 is engaged in the hub 30 and includes a non-circular or hexagonal outer peripheral surface for engaging with a hexagonal bore of the hub 30 and for allowing the central tube 31 to be rotated in concert with the hub 30. The central tube 31 includes a splined inner bore 32 for receiving and mating with the externally splined portion 70 of the propeller shaft 7 and for allowing the hub 30 to be rotated in concert with the propeller shaft 7.

A tubular propeller housing 80 includes three or more angularly spaced propeller blades 802 and includes three or more pairs of lobes 820 extended radially inward from the inner peripheral surface 81 of the tubular propeller housing 80 for forming and defining three or more keyways 82 which are provided for engaging with the keys 33 of the hub 30. The keyways 82 each includes a narrower outer end for engaging with the narrower outer end 332 of the key 33 and each includes a wider inner end for engaging with the wider inner end 334 of the key 33 such that the keys 33 may be prevented from being disengaged from the tubular propeller housing 80. Three or more stops 83 are disposed between the pairs of lobes 820 and include an outer end 830 flush with the outer ends of the lobes 820.

A retainer disc 40 includes a number of angularly spaced ears 41 for engaging with the outer ends of the lobes 820 and for engaging with the outer ends 830 of the stops 83 and for preventing the lobes 820 and the stops 83 from passing the ears 41 of the retainer disc 40. The retainer disc 40 includes a splined bore 42 for engaging with and for mating with the externally splined portion 70 of the propeller shaft 7. A spoked washer 50 is engaged between the retainer disc 40 and the locking nut 60 for preventing the locking nut 60 from being rotated by the tubular propeller housing 80.

It is to be noted that, as shown in FIG. 3, the number of the stops 83 are preferably equals to that of the ears 41 and are provided for engaging with the ears 41. The distance between any two adjacent stops 83 is greater than the distance between any two adjacent ears 41 for preventing the stops 83 from moving beyond the ears 41 and for preventing the tubular propeller housing 80 from being disengaged from the retainer disc 40, such that the tubular propeller housing 80 may be safely and solidly retained in place.

Accordingly, the propeller assembly in accordance with the present invention may be solidly secured to the propeller shaft and may be prevented from being disengaged from the propeller shaft inadvertently.

Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made by way of example only and that numerous changes in the detailed construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.