WO2015050508A1

WO2015050508A1 - Controllable pitch propeller

Info

Publication number: WO2015050508A1
Application number: PCT/TH2013/000054
Authority: WO
Inventors: Kitipan CHOMTONGDEE
Original assignee: Chomtongdee Kitipan
Priority date: 2013-10-04
Filing date: 2013-10-04
Publication date: 2015-04-09

Abstract

A controllable pitch propeller assembly comprises a propeller assembly, a shaft assembly and a collar assembly. A hub (1) is reciprocally installed on a shaft (6) through splines (6a). A number of blades (3) on pivot shafts (4) around the hub (1) have internal crank pins (4a) held by associated transverse slots (5) on the shaft (6). A propeller collar (11) is connected to the hub (1) through a twin thrust bearings (10). Pitch control can be done by two structures. For the propeller control structure, the propeller will be connected to a fixed shaft, pitch control will be done by adjusting the propeller position on the fixed shaft through a reciprocal movement control mechanism connected to the propeller collar (l l).For the shaft control structure, the propeller collar (11) will be fixed to a shaft sleeve, pitch control will be done by adjusting shaft end position in the propeller by means of an extensible shaft.

Description

CONTROLLABLE PITCH PROPELLER

Technical Field

This invention relates to Marine Engineering. Background Art

For marine engineering, a controllable pitch propeller is a propeller which the blade angle can be controlled for high, low or reverse thrust as desired. Thrust control using controllable pitch propellers can be done continuously at the speed of highest machine efficiency, therefore, controllable pitch propellers are widely used for energy saving. The controllable pitch propeller has blades on pivot shafts around the hub. Each blade shaft has a crank pin controlled by a transverse slot on the core of the hub. Sliding the core of the hub in the shaft direction can turn the blades to the desired angle. Most controllable pitch propellers use a hollow shaft where hydraulic control can be inserted into the hub to slide the core for pitch control. Since a controllable pitch propeller requires a hub assembly, a hollow shafts and a hydraulic control system, most of the controllable pitch propellers are used in big ships only.

Summary of Invention

The object of the invention is to build a controllable pitch propeller for boats. Since a controllable pitch propeller using a hollow shaft assembly with a hydraulic control system is too huge for a boat. The problem is how to make a controllable pitch propeller without a hollow shaft.

Examining the operation of the present controllable pitch propeller, pitch adjustment is done by transverse slots on the core of the hub that move the crank pins of the blades, that is, movement of the core inside the fixed hub in shaft direction can change the pitch. On the other hand, if the core of the hub is fixed, movement of the hub body in the counter direction also can change the pitch. By installing transverse slots on a shaft covered by a hub with blades and internal crank pins, letting the crank pins be held by associated slots on the shaft, moving the hub on the shaft by a rotatable collar will change the pitch while the hub can be driven by a spline coupling. This invention makes a small controllable pitch propeller with simple structure and less count of components than the hollow shaft controllable pitch propeller. This propeller can be applied to all boats which will reduce the use of gears and provide a lot of energy saving.

Brief Description of Drawings

Fig. 1 shows the components of the invented controllable pitch propeller. Fig. 2 shows the cross section a-a view of the controllable pitch propeller. Fig. 3 shows the figure of the transverse slots block. Fig. 4 shows an example of an outboard boat application. Fig. 5 shows an example of an inboard boat application. Fig. 6 shows the components of the shaft holder. Fig. 7 shows an example of a long-tail boat application.

Description of Embodiments

Fig. 1 shows the components of the invented controllable pitch propeller assembly which contains 3 discrete parts, a propeller assembly, a shaft assembly and a collar assembly.

The propeller assembly contains a hollow cylindrical hub (1) with an inner gear (la) on one end for propeller drive and a propeller cap (2) with a shaft end supporting socket on another end to prevent hub swinging, a number of blades (3) are connected radially around the hub through the hub wall by screws (3a) to associated pivot shafts (4) inside the hub with crank pins (4a) for pitch control and optional rectangular bushes (5) for heavy duty use.

The shaft assembly contains a drive shaft (6) with a number of splines (6a) to drive the propeller using spline coupling, a transverse slots block (7) with a number of transverse slots (7a) associated to blade crank pins (4a) for pitch control is fixed to the shaft by a spring washer (8) and a long tail propeller nut (9) which acts as shaft end extension to prevent hub swinging. The cross section a-a of the propeller is shown in Fig. 2 with only one blade shown. Fig. 3 shows the figure of the transverse slots block (7) on both sides. The collar assembly contains a propeller collar (1 1) around the neck of the hub (2) with a number of attachment holes (11a) for propeller position control, a twin thrust bearings (10) for push and pull actions between the hub (2) and the propeller collar (11) for the propeller collar (11) rotation and a threaded lock collar (12) to secure the bearings.

The shaft assembly will drive the propeller assembly using spline coupling through the shaft splines (6a) and the propeller inner gear (la). The propeller assembly will be movable reciprocally along the shaft splines (6a). Movement of the propeller on the shaft will change the pitch because the transverse slots (7a) will hold the associated blade crank pins (4a) while the blade pivot shafts (4) move with the hub (1). The rectangular bush (5) is optional for heavy duty propellers to distribute the contact force between blade crank pins (4a) and transverse slots (7a).

The collar assembly is designed to control the position of the propeller on the shaft. Since the propeller collar (11) is connected to the hub through a twin thrust bearings (10), the propeller collar (1 1) will move with the hub on the shaft without rotation and a reciprocal movement control mechanism can be connected to the propeller collar (11) at the attachment holes (1 la) to move the propeller in shaft direction.

Pitch control can be done by two methods, propeller control method and shaft control method. For the propeller control method, the propeller will be connected to a fixed shaft and pitch control will be done by adjusting the propeller position on the shaft by a reciprocal movement control mechanism connected to the propeller collar (11). Example 1 for an outboard boat shows the propeller control method. For the shaft control method, the propeller collar (1 1) will be fixed to a shaft sleeve and pitch control will be done by adjusting the shaft end position in the propeller using an extensible shaft connected to a reciprocal movement control mechanism. Example 2 for an inboard boat and example 3 for a long-tail boat show the shaft control method.

Examples

Example 1 Fig. 4 shows an example of an outboard boat application. The motor (13) has a controllable pitch propeller installed on the drive shaft and a control lever assembly (14) is connected to the propeller collar (11) to adjust the propeller position on the shaft for pitch control.

Example 2 Fig. 5 shows an example of an inboard boat application. The motor (13) has a controllable pitch propeller installed by connecting the propeller collar to the stern tube (15). The drive shaft will be an extensible shaft (16) with a shaft holder (17) on it at the shaft seal (18). A control lever assembly (14) is connected to the shaft holder (17) to control the shaft holder position. Moving the shaft holder (17) will move the shaft (16) and the shaft seal (18) together. Since the propeller is connected to the stern tube, adjusting the shaft holder position by the control lever (14) will adjust the shaft end position in the propeller for pitch control. The shaft holder (17) in Fig. 5 which holds the shaft in axial direction but lets the shaft rotates is detailed in Fig. 6. It contains a shaft lock collar (19) which rotates with the shaft (16), a twin thrust bearings (20) where the inner plates rotate with the shaft (16) but the outer plates stay still with the shell (21). There are also a number of attachment holes (21a) on the shell for control mechanism installation and a number of service holes (21b) for the shaft lock collar (19) service.

Example 3 Fig. 7 shows an example of a long-tail boat application. The motor (13) has a controllable pitch propeller installed by fixing the propeller collar to the stern tube (15). The drive shaft in this case is an extensible shaft (16) with a shaft holder (17) which detailed in Fig. 5 on it. A control lever assembly (14) is connected to the shaft holder (17) to control the shaft holder position. Moving the shaft holder (17) will move the shaft (16). Since the propeller is connected to the stern tube, adjusting the shaft holder position by the control lever (14) will adjust the shaft end position in the propeller for pitch control.

Industrial Applicability

Controllable pitch propeller can be applied for the following industries: 1 Marine industry 2 Aviation industry

3 Blower industry

4 Turbine industry Patent Citations

Cited Patent: US1510436 A

Filing date: Mar 14, 1923

Publication date: Sep 30, 1924

Applicant: Elov Englesson John

Title: Hub for impellers with turnable vanes

Cited Patent: US4474533 A

Filing date: Mar 4, 1983

Publication date: Oct 2, 1984

Applicant: Michinobu Hino

Title: Controllable pitch propeller assembly

Claims

A controllable pitch propeller assembly comprising: a propeller assembly including a hollow cylindrical hub having an inner gear on one end for spline coupling and reciprocal movement on a spline shaft, a socket on another end of said hub for a shaft end supporting, a plurality of blades connected radially around said hub through said hub wall, and a plurality of pivot shafts with crank pins inside said hub connected to associated said blades for pitch control; a shaft assembly for propeller driving and pitch control including a spline shaft for said hub driving, a transverse slots block with a plurality of transverse slots mounted on said spline shaft for the associated said crank pins holding, and a shaft end extension means for being secured by said hub end socket; a collar assembly for position control of said propeller assembly on said shaft assembly including a propeller collar around the neck of said hub for a position control, and a twin thrust bearings inserted between the neck of said hub and said propeller collar for propeller collar rotation. An assembly according to claim 1 , wherein each said crank pin further includes a rectangular bush for heavy duty use. An assembly according to claim 1 and 2, wherein said propeller collar further includes a reciprocal movement control means connected therewith for pitch control.

An assembly according to claim 1 and 2, wherein said propeller collar further includes a shaft sleeve connected therewith for propeller fixed position, said spline shaft further includes an extensible shaft connected therewith for said propeller drive, and said extensible shaft further includes a reciprocal movement control means connected therewith for pitch control.