Adjustable pitch propeller drive

Claim 2

An adjustable pitch propeller comprising a hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner portion which is located within said hub, and an improved mechanism for adjusting the pitch of said propeller blades, comprising: a pair of axially movable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, with each end of said spring means bearing against one of said abutments, said spring means normally biasing both of the abutments axially outwardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; and means for applying an axially inward force on said abutments for moving both abutments axially inwardly together, in opposition to the force of said spring means, for the purpose of rotating the propeller blades in a first direction, with the energy that is stored in such spring means when it is compressed serving to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments, whereby movement of both abutments results in the spring means being compressed at each end.

Claim 3

An adjustable pitch propeller according to claim 1, wherein one of said abutments includes an elongated guide shaft connected thereto, extending axially of the hub, and the second abutment is mounted on said guide shaft to slide axially thereon.

Claim 4

An adjustable pitch propeller according to claim 2, wherein at least one expansible fluid chamber is formed within said hub, of which one of the abutments includes a movable wall for such chamber, and said guide shaft includes a fluid passageway through which fluid flows into and outfrom said expansible chamber.

Claim 5

An adjustable pitch propeller according to claim 3, wherein a separate expansible chamber is associated with each said abutment, and each abutment provides a movable wall for its expansible chamber, and said passageway delivers fluid into and outfrom each such expansible chamber.

Claim 6

An adjustable pitch propeller according to claim 3, wherein there is only one expansible chamber and it is associated with a first one of the abutments, and wherein delivery of fluid into such chamber causes the abutment to move and such movement causes the mechanical drive means connected to such abutment to rotate the propeller blades, and rotation of the propeller blades drives the mechanical drive means connected to the second abutment, causing it to move towards the first abutment, so that the compressing spring is compressed from both ends.

Claim 7

An adjustable pitch propeller according to claim 1, wherein said mechanical drive means comprises a pinion gear attached to the base of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its gear wheel at a location which is diametrically opposite where the rack extending from the other abutment engages such pinion gear.

Claim 8

An adjustable pitch propeller according to claim 6, wherein the rack and pinion drive is adapted to rotate the propeller blades at least 180 degrees during movement of the two abutments from one end position to the other end position.

Claim 9

An adjustable pitch propeller according to claim 6, wherein said spring means engages the abutments at locations radially inwardly of said racks.

Claim 10

An adjustable pitch propeller according to claim 8, wherein each abutment includes a radial end wall against which an end of the spring means presses, and an axial portion which projects axially inwardly from said radial portion, and wherein the end portions of the compression spring means surrounds the axial portions of the abutments.

Claim 11

An adjustable pitch propeller according to claim 6, wherein the hollow hub includes wall means adjacent which said racks extends, and said propeller further includes key means extending between said racks and the wall means, for bracing and guiding the racks.

Claim 12

An adjustable pitch propeller according to claim 10, wherein said key means comprises an axial groove formed in a back portion of each rack, a similar axial groove formed in each portion of the wall means that is adjacent a said rack, and an elongated key member which fits partially within one such groove and partially within the other such groove.

Claim 13

An adjustable pitch propeller according to claim 1, wherein each abutment includes a radial end wall against which an end of the spring means presses, and an axial portion which projects axially inwardly from said radial endwall, and wherein the end portions of the compression spring means surrounds the axial portions of the abutments.

Claim 14

An adjustable pitch propeller according to claim 12, further comprising fluid motor means within said hub for causing movement of said abutment means together, to move the mechanical drive means, to rotate the propeller blades, and to compress the spring means between the two abutments.

Claim 15

An adjustable pitch propeller according to claim 1, wherein said mechanical drive means comprises a toggle drive member attached to the base of each propeller blade, and including a pair of diametrically opposed ears extending radially therefrom, a toggle rod interconnected between each ear and an associated one of the abutments, with axial movement of the abutments causing the toggle rods to push on the ears of the toggle drive member and in that manner cause rotation of the propeller blade.

Claim 16

An adjustable pitch propeller according to claim 1, further comprising fluid operated motor means within said hub for moving the two abutments together, to cause operation of the mechanical drive means resulting in a pitch changing rotational force being applied to the propeller blades, and movement of the two abutments together, compressing the spring means between them, with venting of the fluid drive means causing the spring means to extend and drive the mechanical drive means and the propeller blades in the opposite direction.

Claim 17

An adjustable pitch propeller according to claim 15, wherein the propeller hub includes means at one of its ends for mounting it onto the after end of a propeller shaft, and a swivel means at its opposite end through which operating fluid is supplied and returned to and from the motor means.

Claim 18

An adjustable pitch propeller comprising: a hub having a forward end portion adapted to be mounted onto a rearward end of a propeller shaft; means for securing said hub to said shaft; a plurality of adjustable pitch propeller blades mounted on said hub, each said propeller having an inner end portion which is located within said hub; means for changing the pitch of said propeller blades including axially movable means within said hub, movement of which is controlled by fluid pressure; means for supplying a fluid pressure to cause such movement, said means including a swivel at the rear end of said hub and fluid delivery line means connected to said swivel; and wherein the means for changing the pitch of the propeller blades further includes a pair of axially moveable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, with each end of said spring means bearing against one of said abutments, said spring means normally biasing both of the abutments axially outardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; and a fluid motor means for applying an axially inward force on said abutments, for moving both abutments axially inwardly together, in opposition to the force of said spring means, for the purpose of rotating the propeller blades in a first direction, with the energy that is stored in such spring means when it is compressed serving to rotate the propeller blades in the opposite direction when the axially inwardly directed force provided by the fluid motor means is removed from the abutments.

Claim 19

An adjustable pitch propeller comprising: a hub having a forward end portion adapted to be mounted onto a rearward end of a propeller shaft; means for securing said hub to said shaft; a plurality of adjustable pitch propeller blades mounted on said hub, each said propeller having an inner end portion which is located within said hub; means for changing the pitch of said propeller blades including axially movable means within said hub, movement of which is controlled by fluid pressure; means for supplying a fluid pressure to cause such movement, said means including a swivel at the rear end of said hub and fluid delivery line means connected to said swivel; and wherein the means for changing the pitch of the propeller blades further includes a pair of axially moveable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, with each end of said spring means bearing against one of said abutments, said spring means normally biasing both of the abutments axially outardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; and a fluid motor means for applying an axially inward force on said abutments, for moving both abutments axially inwardly together, in opposition to the force of said spring means, for the purpose of rotating the propeller blades in a first direction, with the energy that is stored in such spring means when it is compressed serving to rotate the propeller blades in the opposite direction when the axially inwardly directed force provided by the fluid motor means is removed from the abutments.

Claim 20

An adjustable pitch propeller according to claim 17, wherein one of said abutments includes an elongated guide shaft connected thereto, extending axially of the hub, and the second abutment is mounted on said guide shaft to slide axially thereon.

Claim 21

An adjustable pitch propeller according to claim 18, wherein at least one expansible fluid chamber is formed within said hub, of which one of the abutments includes a moveable wall for such chamber, and said guide shaft includes a fluid passageway through which fluid flows into and outfrom said expansible chamber.

Claim 22

An adjustable pitch propeller according to claim 19, wherein a separate expansible chamber is associated with each said abutment, and each abutment provides a moveable wall for its expansible chamber, and said passageway delivers fluid into and outfrom each such expansible chamber.

Claim 23

An adjustable pitch propeller according to claim 19, wherein there is only one expansible chamber and it is associated with a first one of the abutments, and wherein delivery of fluid into such chamber causes the abutment to move and such movement causes the mechanical drive means connected to such abutment to rotate the propeller blades, and rotation of the propeller blades drives the mechanical drive means connected to the second abutment, causing the second abutment to move towards the first abutment, so that the compression spring is compressed from both ends.

Claim 24

An adjustable pitch propeller according to claim 17, wherein said mechanical drive means comprises a pinion gear attached to the base of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its gear wheel at a location which is diametrically opposite where the rack extending from the other abutment engages such pinion gear.

Claim 25

An adjustable pitch propeller according to claim 22, wherein the rack and pinion drive is adapted to rotate the propeller blades at least 180 degrees during movement of the two abutments from one end position to the other end position.

Claim 26

An adjustable pitch propeller according to claim 22, wherein said spring means engages the abutments at locations radially inwardly of said racks.

Claim 27

An adjustable pitch propeller according to claim 24, wherein each abutment includes a radial end wall against which an end of the spring means presses, and an axial portion which projects axially inwardly from said radial portion, and wherein the end portions of the compression spring means surrounds the axial portions of the abutments.

Claim 28

An adjustable pitch propeller according to claim 22, wherein the hollow hub includes wall means adjacent which said racks extend, and said propeller further includes key means extending between said racks and the wall means, for bracing and guiding the racks.

Claim 29

An adjustable pitch propeller according to claim 26, wherein said key means comprises an axial groove formed in a back portion of each rack, a similar axial groove formed in each portion of the wall means that is adjacent a said racks, and an elongated key member which fits partially within one such groove and partially within the other such groove.

Claim 30

An adjustable pitch propeller having a hollow hub including a peripheral blade mounting portion comprising: a circular opening and an annular wall surrounding said opening which is flat on both its sides, a pair of annular plastic bushings, one on each side of said annular wall; a propeller blade including an elongated blade portion having inner and outer ends and a mounting base at its inner end; said mounting base comprising a cylindrical end portion sized to fit through both bushings and the opening in the mounting portion of the hub; an annular flange extending about said cylindrical portion at the end thereof adjacent the blade portion, presenting an inner surface which rests against an outside surface of the outer bushing; a flat end surface at the opposite end of said cylindrical portion which is substantially flush with the inside surface of the inner bushing; means for securing the propeller blade in place on the hub comprising a wall member which is positionable against the inner end surface of said blade hub and extends radially beyond the cylindrical portion of said hub to inwardly bound the inside surface of the inner bushing; a propeller blade drive element inwardly of said wall member, and means for removably securing said drive element and said wall member to the base of the propeller blade; a pair of force applying elements drivenly connected to said drive element at diametrically opposite locations; a pair of axially moveable abutments spaced axially apart within said hub; a compressing spring means positioned between said abutments, with each end of said spring means bearing against one of said abutments, said spring means normally biasing both of the abutments axially outwardly; wherein one of the force applying members is connected to the other abutment; and means for applying an axially inward force on said abutments for moving both abutments axially inwardly together, in opposition to the force of said spring means, for the purpose of rotating the propeller blade in a first direction, with the energy that is stored in such spring when it is compressed serving to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments.

Claim 31

An adjustable pitch propeller having a hollow hub including a peripheral blade mounting portion comprising: a circular opening and an annular wall surrounding said opening which is flat on both its sides, a pair of annular plastic bushings, one on each side of said annular wall; a propeller blade including an elongated blade portion having inner and outer ends and a mounting base at its inner end; said mounting base comprising a cylindrical end portion sized to fit through both bushings and the opening in the mounting portion of the hub; an annular flange extending about said cylindrical portion at the end thereof adjacent the blade portion, presenting an inner surface which rests against an outside surface of the outer bushing; a flat end surface at the opposite end of said cylindrical portion which is substantially flush with the inside surface of the inner bushing; means for securing the propeller blade in place on the hub comprising a wall member which is positionable against the inner end surface of said blade hub and extends radially beyond the cylindrical portion of said hub to inwardly bound the inside surface of the inner bushing; a propeller blade drive element inwardly of said wall member, and means for removably securing said drive element and said wall member to the base of the propeller blade; a pair of force applying elements drivenly connected to said drive element at diametrically opposite locations; a pair of axially moveable abutments spaced axially apart within said hub; a compressing spring means positioned between said abutments, with each end of said spring means bearing against one of said abutments, said spring means normally biasing both of the abutments axially outwardly; wherein one of the force applying members is connected to the other abutment; and means for applying an axially inward force on said abutments for moving both abutments axially inwardly together, in opposition to the force of said spring means, for the purpose of rotating the propeller blade in a first direction, with the energy that is stored in such spring when it is compressed serving to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments.

Claim 32

An adjustable pitch propeller having a generally hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner end portion which is located within said hub, and an improved mechanism for varying the pitch of the propeller blades, comprising: a pair of axially movable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, each end of the spring means bearing on a respective abutment to normally bias both of the abutments axially outwardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; means for applying an axially inward force on said abutments for moving both abutments axially inwardly toward each other in opposition to the force of said spring means to compress the spring means at each end and to rotate the propeller blades in a first direction, and to store energy in the compressed spring means to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments; a drive shaft secured to one end of said hub, said shaft and said hub being rotatable on a common axis; said means for applying said axially inward force including a pair of internal drive shaft elements extending outwardly from said hub within the drive shaft, one of said elements being connected to one abutment and the other element being connected to the other abutment to apply said axially inward force respectively thereto; and means on said elements and rotatable with said drive shaft to receive said force and to be moved axially so as to move said abutments axially inwardly.

Claim 33

An adjustable pitch propeller having a generally hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner end portion which is located within said hub, and an improved mechanism for varying the pitch of the propeller blades, comprising: a pair of axially movable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, each end of the spring means bearing on a respective abutment to normally bias both of the abutments axially outwardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; means for applying an axially inward force on said abutments for moving both abutments axially inwardly toward each other in opposition to the force of said spring means to compress the spring means at each end and to rotate the propeller blades in a first direction, and to store energy in the compressed spring means to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments; a drive shaft secured to one end of said hub, said shaft and said hub being rotatable on a common axis; said means for applying said axially inward force including a pair of internal drive shaft elements extending outwardly from said hub within the drive shaft, one of said elements being connected to one abutment and the other element being connected to the other abutment to apply said axially inward force respectively thereto; and means on said elements and rotatable with said drive shaft to receive said force and to be moved axially so as to move said abutments axially inwardly.

Claim 34

The invention according to claim 29 in which: said spring means include a plurality of coil springs being generally concentric with respect to each other.

Claim 35

The invention according to claim 29 in which: said internal drive shaft elements are comprised of a rod connected to one of said abutments and a tube connected to the other of said abutments; said rod and tube being movable axially relative to each other.

Claim 36

The invention according to claim 31 in which: said means on said elements are juxtaposed pistons having an expansible chamber therebetween; one of said pistons being on said tube and the other being on said rod; a fluid power passage through said rod to said chamber, said fluid being adapted to flow into and out of said chamber through said passage.

Claim 37

The invention according to claim 32 in which: said expansible chamber is surrounded by a cylindrical member in which said pistons are sealingly engaged for axial movement; said cylindrical member being secured to said shaft to rotate therewith.

Claim 38

The invention according to claim 33 in which: said rod and tube being movable axially relative to each other within and outwardly of said cylindrical member.

Claim 39

The invention according to claim 34 in which: delivery of fluid into said expansible chamber causes the abutments to be moved simultaneously axially inwardly to operate the mechanical drive means to rotate the propeller blades and to compress the spring means at both ends.

Claim 40

The invention according to claim 35 in which: said mechanical drive means includes a pinion gear attached to a base on the inner end of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its pinion gear at a location which is diametrically opposite where the rack extending from the other abutment engages the pinion gear.

Claim 41

The invention according to claim 36 in which: the rack and pinion drives are adapted to rotate the propeller blades at least 180 degrees during movement of the two abutments from an axially outer position to an axially inner position where said spring means are compressed at both ends a predetermined amount.

Claim 42

The invention according to claim 36 in which: the spring means bear on the abutments at locations radially inwardly of said racks.

Claim 43

The invention according to claim 36 in which: the hub includes wall means adjacent which said racks extend, and key means extend between said racks and said wall means for bracing and guiding the racks.

Claim 44

The invention according to claim 39 in which: said key means includes an axial groove in a back portion of each rack, a similar axial groove formed in each portion of the wall means that is adjacent a said rack, and an elongated key member which fits partially within one such groove and partially within the other such groove.

Claim 45

The invention according to claim 34 in which: said rod is slidably engaged within said tube.

Claim 46

The invention according to claim 31 in which: said abutment connected to said rod is cup-shaped and the bottom of the cup receives said spring means; said cup-shaped abutment having an annular circumferential flange to which said mechanical drive means are connected; said abutment connected to said tube has surfaces which receive said spring means and has axial protrusions which position said spring means radially; said last abutment having an annular circumferential flange to which said mechanical drive means are connected.

Claim 47

The invention according to claim 29 in which: said means on said elements are juxtaposed pistons, one on each of said elements; said pistons having an expansible chamber therebetween; a fluid power passage through one of said elements to said chamber, said fluid being adapted to flow into and out of said chamber through said passage.

Claim 48

The invention according to claim 29 including: fluid operated motor means associated with said drive shaft for moving the two abutments toward each other to cause operation of the mechanical drive means resulting in a pitch changing rotational force being applied to the propeller blades and compressing the spring means between them, with venting of the fluid drive means causing the spring means to extend and drive the mechanical drive means and the propeller blades in the opposite direction.

Claim 49

An adjustable pitch propeller comprising: a generally hollow hub having a forward end portion adapted to be mounted onto a rearward end of a propeller shaft; means for securing said hub to said shaft; a plurality of adjustable pitch propeller blades mounted on said hub, each of said propeller blades having an inner base portion located within said hub; a pair of axially movable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, each end of the spring means bearing on a respective abutment to normally bias both of the abutments axially outwardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; means within said hub for applying an axially inward force to said abutments for moving both abutments axially inwardly toward each other in opposition to the force of said spring means to compress the spring means at each end and to rotate the propeller blades in a first direction, and to store energy in the compressed spring means to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments; said means within said hub for applying said axially inward force including a pair of elements within the hub and adapted to extend into a drive shaft outwardly of said hub; and one of said elements being connected to one abutment and the other element being connected to the other abutment to apply said axially inward force respectively thereto.

Claim 50

An adjustable pitch propeller comprising: a generally hollow hub having a forward end portion adapted to be mounted onto a rearward end of a propeller shaft; means for securing said hub to said shaft; a plurality of adjustable pitch propeller blades mounted on said hub, each of said propeller blades having an inner base portion located within said hub; a pair of axially movable abutments spaced axially apart within said hub; compression spring means positioned between said abutments, each end of the spring means bearing on a respective abutment to normally bias both of the abutments axially outwardly; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; means within said hub for applying an axially inward force to said abutments for moving both abutments axially inwardly toward each other in opposition to the force of said spring means to compress the spring means at each end and to rotate the propeller blades in a first direction, and to store energy in the compressed spring means to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments; said means within said hub for applying said axially inward force including a pair of elements within the hub and adapted to extend into a drive shaft outwardly of said hub; and one of said elements being connected to one abutment and the other element being connected to the other abutment to apply said axially inward force respectively thereto.

Claim 51

The invention according to claim 45 including: means adapted to be secured to said elements externally of said hub and drive shaft to receive said force and to be moved axially so as to move said abutments axially inwardly.

Claim 52

The invention according to claim 45 in which: one of said elements is a rod connected to one of said abutments to move it axially and the other of said elements is a tube connected to the other of said abutments to move it axially; said rod and said tube extending forwardly outwardly of said hub, said rod being slidably engaged within said tube.

Claim 53

The invention according to claim 47 including: means on said elements externally of said hub and of a drive shaft and rotatable with said drive shaft to receive said force and to be moved axially to move said abutments axially inwardly; said means on said elements being juxtaposed pistons having an expansible chamber therebetween; one of said pistons being on said tube and the other being on said rod; and a fluid power passage through said rod to said chamber, said fluid being adapted to flow into and out of said chamber through said passage.

Claim 54

The invention according to claim 48 in which: said expansible chamber is surrounded by a cylindrical member in which said pistons are sealingly engaged for axial movement; said cylindrical member is securable to said shaft to rotate therewith.

Claim 55

The invention according to claim 49 in which: delivery of said fluid into said expansible chamber causes the abutments to be moved simultaneously axially inwardly to operate the mechanical drive means to rotate the propeller blades and to compress the spring means at both ends.

Claim 56

The invention according to claim 45 in which: said abutment connected to said rod is cup-shaped and the bottom of the cup receives said spring means; said cup-shaped abutment having an annular circumferential flange to which said mechanical drive means are connected; said abutment connected to said tube has surfaces which receive said spring means and has axial protrusions which position said spring means radially; said last abutment having an annular circumferential flange to which said mechanical drive means are connected.

Claim 57

The invention according to claim 45 in which: said mechanical drive means includes a pinion gear attached to a base on the inner end of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its pinion gear at a location which is diametrically opposite where the rack extending from the other abutment engages the pinion gear.

Claim 58

The invention according to claim 52 in which: the rack and pinion drives are adapted to rotate the propeller blades at least 180 degrees during movement of the two abutments from an axially outer position to an axially inner position where said spring means are compressed at both ends a predetermined amount.

Claim 59

The invention according to claim 52 in which: the spring means bear on the abutments at locations radially inwardly of said racks.

Claim 60

The invention according to claim 52 in which: the hub includes wall means adjacent which said racks extend, and key means extend between said racks and said wall means for bracing and guiding the racks.

Claim 61

The invention according to claim 55 in which: said key means includes an axial groove in a back portion of each rack, a similar axial groove formed in each portion of the wall means that is adjacent a said rack, and an elongated key member which fits partially within one such groove and partially within the other such groove.

Claim 62

The invention according to claim 45 including: fluid operated motor means associated with said hub and a drive shaft for moving the two abutments toward each other to cause operation of the mechanical drive means resulting in a pitch changing rotational force being applied to the propeller blades, and compressing the spring means between them, with venting of the fluid drive means causing the spring means to extend and drive the mechanical drive means and the propeller blades in the opposite direction.

Claim 63

An adjustable pitch propeller having a generally hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner end portion which is located within said hub, and an improved mechanism for varying the pitch of the propeller blades, comprising: a pair of axially movable abutments spaced axially apart within said hub; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; compression spring means associated with said abutments to normally bias both of the abutments axially outwardly; means associated with said hub for applying an axially inward force on said abutments for moving both abutments axially inwardly toward each other in opposition to the force of said spring means to compress the spring means at a plurality of spring ends and to rotate the propeller blades in a first direction, and to store energy in the compressed spring means to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments.

Claim 64

An adjustable pitch propeller having a generally hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner end portion which is located within said hub, and an improved mechanism for varying the pitch of the propeller blades, comprising: a pair of axially movable abutments spaced axially apart within said hub; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to an axial movement of its abutment; compression spring means associated with said abutments to normally bias both of the abutments axially outwardly; means associated with said hub for applying an axially inward force on said abutments for moving both abutments axially inwardly toward each other in opposition to the force of said spring means to compress the spring means at a plurality of spring ends and to rotate the propeller blades in a first direction, and to store energy in the compressed spring means to rotate the propeller blades in the opposite direction when the axially inwardly directed force is removed from the abutments.

Claim 65

The invention according to claim 58 in which: said mechanical drive means includes a pinion gear attached to a base on the inner end of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its pinion gear at a location which is diametrically opposite where the rack extending from the other abutment engages the pinion gear.

Claim 66

The invention according to claim 59 in which: the rack and pinion drives are adapted to rotate the propeller blades at least 180 degrees during movement of the two abutments from an axially outer position to an axially inner position, at which time said spring means are compressed at a plurality of ends a predetermined amount.

Claim 67

The invention according to claim 59 in which: the hub includes wall means adjacent which said racks extend, and key means extend between said racks and said wall means for bracing and guiding the racks.

Claim 68

The invention according to claim 61 in which: said key means includes an axial groove in a back portion of each rack, a similar axial groove formed in each portion of the wall means that is adjacent a said rack, and an elongated key member which fits partially within one such groove and partially within the other such groove.

Claim 69

The invention according to claim 58 in which: said means associated with said hub for applying an axially inward force on said abutments include fluid operated motor means to cause operation of the mechanical drive means resulting in a pitch changing rotational force being applied to the propeller blades, and compressing the spring means, with venting of the fluid drive means causing the spring means to extend and drive the mechanical drive means and the propeller blades in the opposite direction.

Claim 70

An adjustable pitch propeller having a generally hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner end portion which is located within said hub, and an improved mechanism for varying the pitch of the propeller blades, comprising: a pair of axially moveable abutments spaced axially apart within said hub; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to axial movement of its abutment; and means associated with said hub for applying an axially inward force on said abutments for moving both abutments axially inwardly toward each other to rotate the propeller blades for pitch variation; said mechanical drive means including a pinion gear attached to a base on the inner end of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its pinion gear at a location which is diametrically opposite where the rack extending from the other abutment engages the pinion gear.

Claim 71

An adjustable pitch propeller having a generally hollow hub, a plurality of adjustable pitch propeller blades mounted on said hub, each of said blades having an inner end portion which is located within said hub, and an improved mechanism for varying the pitch of the propeller blades, comprising: a pair of axially moveable abutments spaced axially apart within said hub; a mechanical drive means interconnected between each abutment and the inner end portion of each blade, each of said mechanical drive means functioning to apply a pitch changing rotational force on its blade in response to axial movement of its abutment; and means associated with said hub for applying an axially inward force on said abutments for moving both abutments axially inwardly toward each other to rotate the propeller blades for pitch variation; said mechanical drive means including a pinion gear attached to a base on the inner end of each propeller blade, and a separate drive rack extending axially inwardly from each abutment to each pinion gear, with the rack for each abutment engaging its pinion gear at a location which is diametrically opposite where the rack extending from the other abutment engages the pinion gear.

Claim 72

The invention according to claim 64 in which: the rack and pinion drives are adapted to rotate the propeller blades at least 180 degrees during movement of the two abutments from an axially outer position to an axially inner position.

Claim 73

The invention according to claim 64 in which: the hub includes wall means adjacent which said racks extend, and key means extend between said racks and said wall means for bracing and guiding the racks.

Claim 74

The invention according to claim 66 in which: said key means includes an axial groove in a back portion of each rack, a similar axial groove formed in each portion of the wall means that is adjacent a said rack, and an elongated key member which fits partially within one such groove and partially within the other such groove.

Claim 75

The invention according to claim 64 in which: said means associated with said hub for applying an axially inward force on said abutments include fluid operated motor means to cause operation of the mechanical drive means resulting in a pitch changing rotational force being applied to the propeller blades.