Modulatable power transmission clutch and a marine transmission

A power transmission housing, a marine transmission located in said housing and for variable speed control of a boat having a propeller for providing modulatable lower speed in both forward and reverse direction for maneuvering during docking of said boat to provide enhanced docking control and boat positioning;

• said transmission providing seamless transition from modulation during which speed can be increased slightly to full clutch engagement and capacity for driving said propeller;
• said transmission including a modulatable power transmission clutch including interleaved clutch plates, said clutch comprising a power transmitting shaft extending axially and centrally through said clutch mounted thereon, said clutch including a fluid operated movable piston for effecting clutch operation by compression of said plates, said piston having two separate fluid application piston areas of different areas thereon, one smaller of said piston areas being adapted to have fluid flow directed thereto at a variable fluid pressure whereby said clutch is modulatable for said docking, the other larger of said piston areas being adapted to have fluid flow directed thereto to effect maximum and unmodulatable engagement of said clutch for driving said propeller;
• and a sequence valve for controlling fluid flow to said other larger of said piston areas in response to fluid pressure at said one smaller of said piston areas, said sequence valve being mounted on said transmission housing and at the exterior of said housing, said valve being spring loaded to a normally closed position in which pressure fluid is directed to said one smaller piston area at a variable fluid pressure whereby said clutch is modulatable, and when said valve is open it permits fluid flow to said other larger of said piston area to effect maximum and unmodulatable engagement of said clutch for full clutch capacity available to said propeller.

A power transmission housing, a power transmission in said housing and including a forward modulatable power transmission clutch and a rear modulatable power transmission clutch, said forward clutch connected in power receiving connection with a prime mover and in power delivering connection with load to be driven,

• said rear clutch being connected in driven engagement with said forward clutch and engageable with said load to be driven for driving the latter in a reverse direction,
• said forward and rear clutches each including clutch plates, a power transmitting shaft extending axially and centrally therethrough, said clutches each including a fluid operated movable piston for effecting clutch operation by compression of said plates, said piston having two separate fluid application piston areas of different areas thereon, one smaller of said piston areas being adapted to have fluid flow directed thereto at a variable fluid pressure whereby said clutch is modulatable, the other larger of said piston areas being adapted to have fluid flow directed thereto to effect maximum and unmodulatable engagement of said clutch;
• and sequence valve means for controlling fluid flow to said other larger of said piston areas in response to fluid pressure above a predetermined amount at said one smaller of said piston areas, said sequence valve means being mounted on the exterior of said housing and accessible therefrom, said sequence valve means being spring loaded to a normally closed position in which pressure fluid is directed to said one smaller piston area at a variable fluid pressure whereby said clutch is modulatable, and when said valve means is open it permits fluid flow to said other larger of said piston area to effect maximum and unmodulatable engagement of said clutch for full clutch capacity.

A power transmission housing, a marine transmission mounted in said housing for variable speed control of a boat having a propeller for providing modulatable lower speed in both forward and reverse direction for maneuvering during docking of said boat to provide enhanced docking control and boat positioning;

• said transmission providing seamless transition from modulation during which speed can be increased slightly to full clutch engagement and capacity for driving said propeller;
• said transmission including a forward modulatable power transmission clutch and a rear modulatable power transmission clutch, said forward clutch connected in power receiving connection with a prime mover and in power delivering connection with load to be driven,
• said rear clutch being connected in driven engagement with said forward clutch and engageable with said load to be driven for driving the latter in a reverse direction,
• said forward and rear clutches each including clutch plates, a power transmitting shaft extending axially and centrally therethrough, said clutches including a fluid operated movable piston for effecting clutch operation by compression of said plates, said piston having two separate fluid application piston areas of different areas thereon, one smaller of said piston areas being adapted to have fluid flow directed thereto at a variable fluid pressure whereby said clutch is modulatable for said docking, the other larger of said piston areas being adapted to have fluid flow directed thereto to effect maximum and unmodulatable engagement of said clutch for driving said propeller;
• and for each of said forward and rear clutches,
• a trigger valve for controlling fluid flow to said other larger of said piston areas in response to fluid pressure above a certain value at said one smaller of said piston areas, a first pressure fluid passage in said shaft for conducting pressure fluid to said smaller area and a second pressure fluid passage in said shaft for conducting pressure fluid to said larger piston area, said trigger valve being located on an outer side of said transmission housing and easily accessible from the outside of said housing, said trigger valve being spring loaded to a normally closed position in which pressure fluid is directed to said one smaller piston area at a variable fluid pressure whereby said clutch is modulatable, said trigger valve when closed acting to block flow of fluid below a predetermined pressure to said larger area, and when said trigger valve is open acting to permit fluid flow above a predetermined pressure to said larger area of said piston to effect maximum and unmodulatable engagement of said clutch for full clutch capacity,
• and an electronic control circuit for said transmission including a source of pressure fluid, a proportional valve connected to said source for delivering pressure fluid to said rear clutch, said source connected to another proportional valve for delivering pressure fluid to said forward clutch,
• said circuit also including a control lever operatively connected with said proportional valves for selective operation thereof to effect forward or reverse operation of said boat.