Marine jet drive with impeller-end and engine-end flexible couplings

• US 6,358,107 B1
• Filed: 03/31/2000
• Issued: 03/19/2002
• Est. Priority Date: 05/13/1991
• Status: Expired due to Fees

• Current Assignee: APEX Hydro Jet, LLC, Peter N. Jansson
• Original Assignee: American Hydro Jet Corporation
• Inventors: Roos, Paul W.
• Primary Examiner(s): SWINEHART, EDWIN L
• Application Number:
  US09/540,135
• Time in Patent Office: 718 Days
• Field of Search: 602/21, 602/22, 440/38, 440/73, 440/83, 416/134.R
• US Class Current: 440/83
• CPC Class Codes: B63H 11/01 having means to prevent foreign material from clogging fluid passage way
• CPC Class Codes: B63H 11/08 of rotary type
• CPC Class Codes: B63H 11/11 with bucket or clamshell-type reversing means
• CPC Class Codes: B63H 11/113 Pivoted outlet
• CPC Class Codes: B63H 11/117 Pivoted vane
• CPC Class Codes: B63H 2023/327 Sealings specially adapted for propeller shafts or stern tubes
• CPC Class Codes: B63H 23/321 Bearings or seals specially adapted for propeller shafts

Abstract

A marine jet drive having a rotatable impeller, an impeller housing, an intake duct, a diffusor housing rearward of the impeller housing, an engine, and a unitary drive shaft extending from the engine to the impeller, and having a rear flexible coupling connecting the drive shaft to the impeller and a front flexible coupling connecting the drive shaft to the engine. Certain preferred embodiments include a shaft sleeve and rear seal assembly isolating the drive shaft from water and debris.

Claims

1. In a vessel-propelling marine jet drive having forward and rearward ends, a rotatable impeller, an impeller housing around the impeller, an intake duct forward of the impeller housing, a diffusor housing rearward of the impeller housing, an engine, and a drive shaft extending from the engine to the impeller, the improvement comprising:

a rear flexible coupling flexibly connecting the drive shaft to the impeller;

a front flexible coupling flexibly connecting the drive shaft to the engine; and

the drive shaft being substantially unsupported between the front and rear flexible couplings.

2. The marine jet drive of claim 1 wherein the front flexible coupling is inside the vessel and directly coupled to the engine.

3. The marine jet drive of claim 1 wherein the drive shaft is a unitary shaft.

4. In a vessel-propelling marine jet drive having forward and rearward ends, a rotatable impeller, an impeller housing around the impeller, an intake duct forward of the impeller housing, a diffusor housing rearward of the impeller housing, an engine, and a drive shaft extending from the engine to the impeller, the improvement comprising:

a rear flexible coupling flexibly connecting the drive shaft to the impeller;

a front flexible coupling flexibly connecting the drive shaft to the engine, said front flexible coupling being inside the vessel and directly coupled to the engine; and

a bearing support structure disposed inside the diffusor housing and rotatively supporting the impeller.

5. The marine jet drive of claim 4 wherein the bearing support structure is rigidly attached to the diffusor housing by a plurality of radially disposed stator vanes.

6. The marine jet drive of claim 4 wherein:

the rear flexible coupling includes a drive shaft tube having at least one key for connection to the impeller; and

the drive shaft is flexibly connected to the drive shaft tube by the rear flexible coupling.

7. The marine jet drive of claim 6 wherein the bearing support structure is rigidly attached to the diffusor housing by a plurality of radially disposed stator vanes.

8. The marine jet drive of claim 4 wherein the rear flexible coupling is disposed within the bearing support structure.

9. The marine jet drive of claim 4 wherein the drive shaft is a unitary shaft.

10. In a vessel-propelling marine jet drive having forward and rearward ends, a rotatable impeller, an impeller housing around the impeller, an intake duct forward of the impeller housing, a diffusor housing rearward of the impeller housing, an engine, and a drive shaft extending from the engine to the impeller, the improvement comprising:

a rear flexible coupling flexibly connecting the drive shaft to the impeller;

a front flexible coupling flexibly connecting the drive shaft to the engine;

a wall structure forward of the impeller and defining the intake duct, the drive shaft extending across a portion of the intake duct;

a shaft sleeve secured with respect to the wall structure and having front and rear ends; and

a seal assembly at the rear end of the shaft sleeve, whereby the drive shaft is isolated from water and debris.

11. The marine jet drive of claim 10 wherein the seal assembly includes a seal cartridge between the shaft sleeve and the impeller.

12. The marine jet drive of claim 11 wherein the impeller includes an impeller hub and a rotating outer housing member secured with respect thereto, the seal assembly includes the outer housing member and the seal cartridge, and the seal cartridge includes:

a rotating seal element;

a static seal element contacting the rotating seal element, the rotating and static seal elements have sealing faces engaged with one another;

an inner housing member adjacent to and enclosing a portion of the static seal element and in releaseable sealing engagement with the shaft sleeve; and

a spring between the inner housing member and the static seal element to urge the static seal element against the rotating seal element.

13. The marine jet drive of claim 12 wherein the inner housing member is retained within the outer housing member by an annular-groove-and-pin arrangement which allows free rotation of the outer housing member about the inner housing member but prevents the inner housing member from being axially separated from the outer housing member.

14. The marine jet drive of claim 13 wherein the annular-groove-and-pin arrangement comprises:

the inner housing member having an outer surface with an annular groove thereon; and

at least one retaining pin through the outer housing member and extending into the annular groove, such retaining pin(s) being withdrawable from the annular groove to allow removal of the seal cartridge from the outer housing member.

15. The marine jet drive of claim 12 wherein:

the shaft sleeve has a rear recess;

the inner housing member has a forward portion removably inserted into the rear recess; and

the forward portion has a compressible seal engaging the shaft sleeve within the rear recess,

thereby providing sealing engagement while permitting release of the seal cartridge when axial pull is applied, to separate the inner housing from the shaft sleeve.

16. The marine jet drive of claim 12 wherein the outer housing member has at least one radially-disposed port therethrough adjacent to the static seal element, whereby centrifugal action upon rotation of the outer housing member causes water to be drawn past the static seal element and out through the port(s) to facilitate cooling of the sealing surfaces.

17. The marine jet drive of claim 16 wherein the static seal element includes cooling fins to facilitate heat transfer from the seal elements to the flowing water.

18. The marine jet drive of claim 12 further including a debris-cutting device comprising:

at least one rotating blade secured to the outer housing member; and

at least one fixed blade secured with respect to the shaft sleeve in position such that the rotating blade rotates past the fixed blade(s) to sever debris.

19. The marine jet drive of claim 10 wherein the drive shaft is a unitary shaft.