1. An actuator (10) comprising:
a first drive pulley (28);
a second drive pulley (29), the first drive pulley and the second drive pulley being interconnected to rotate together;
a first driven pulley (52; 70);
a second driven pulley (53; 72);
a first guide pulley (48);
a second guide pulley (49);
an endless drive belt (40) engaging the first and second drive pulleys, the first and second driven pulleys and the first and second guide pulleys;
a motor (19) connected to drive the first and second drive pulleys to rotate and drive the endless drive belt
a driven member (50; 88; 71, 73) carrying at least one of the driven pulleys; the first and second drive pulleys being arranged so that upon rotation thereof the circumferential speed of the first drive pulley is different from the circumferential speed of the second drive pulley, the endless drive belt being looped around the drive pulleys, the driven pulleys and the guide pulleys so that the difference between the circumferential speed of the first drive pulley and the circumferential speed of the second drive pulley causes movement of the driven member;
wherein each of the drive pulleys, driven pulleys and guide pulleys having a respective axis of rotation, two of the pulleys being angled pulleys, the axis of rotation of the angled pulleys being angled relative to the axis of rotation of the other pulleys whereby the drive belt undergoes twisting movement on the path between the angled pulley and an adjacent pulley.
2. An actuator according to claim 1 in which the first and second drive pulleys are arranged so that upon rotation thereof the circumferential speeds differ because of
the first drive pulley having a different circumferential length than the second drive pulley.
3. (canceled)
4. An actuator according to claim 1 in which the driven member is a carriage (50; 88) mounted for linear movement.
5. An actuator according to claim 4 in which the first driven pulley and the second driven pulley are both mounted upon the carriage (50; 88).
6. An actuator according to claim 5 in which the driven pulleys (52, 53) are located between the drive pulleys (28, 29) and the guide pulleys (48, 49).
7. (canceled)
8. An actuator according to claim 6 having a third driven pulley (84) and a fourth driven pulley (85), the drive pulleys (28, 29) and all four of the driven pulleys (52, 53, 84, 85) being mounted upon the driven member (88), in which the endless drive belt passes from the first drive pulley (28) to the first driven pulley (52), from the first driven pulley to the first guide pulley (48), from the first guide pulley to the third driven pulley (84), from the third driven pulley to the second drive pulley (29), from the second drive pulley to the fourth driven pulley (85), from the fourth driven pulley to the second guide pulley (49), from the second guide pulley to the second driven pulley (53), and from the second driven pulley back to the first drive pulley, the endless drive belt defining a first loop between the first guide pulley and the first and third driven pulleys, and a second loop between the second guide pulley and the second and fourth driven pulleys, rotation of the drive pulleys in a first direction causing an increase in the length of the first loop and a corresponding decrease in the length of the second loop.
9. (canceled)
10. (canceled)
11. An actuator according to claim 1 in which a control line (55; 55a, 55b) is connected to the driven member, movement of the driven member causing corresponding movement of the control line.
12. (canceled)
13. (canceled)
14. An actuator according to claim 1 in which the guide pulleys are the angled pulleys, whereby the drive belt undergoes twisting movement on the path between the guide pulleys and the driven pulleys, but undergoes substantially no lateral movement.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A device for selectively adjusting the pitch of a string of a stringed musical instrument comprising:
a pivotable string puller which pivots about a first axis, said string puller having a string support surface upon which the string rests, wherein pivoting of the string puller about said first axis adjusts the pitch on the string;
a pulley rotatably mounted on said string puller which rotates about a second axis which is spaced apart from said first axis;
a cable wrapped around said pulley, said cable having a first side of the cable extending from a first side of said pulley and a second side of the cable extending from a second side of said pulley, wherein movement of said first side of the cable causes said pulley to move thereby causing the string puller to pivot in a first direction, and movement of said second side of the cable causes said pulley to move thereby causing the string puller to pivot in a second direction;
a first actuator operably coupled to said first side of the cable, said first actuator configured to actuate to move said first side of the cable between a first state in which the first side of the cable is in a normal position such that said string puller is in a normal position and said string is tuned to an open pitch, and a second state in which the first side of the cable is in an adjusted position such that said string puller is in an adjusted position and said string is tuned to a first adjusted pitch different from said open pitch;
a second actuator operably coupled to said second side of the cable, said second actuator configured to actuate to move said second side of the cable between a first state in which the second side of the cable is in a normal position such that said string puller is in a normal position and said string is tuned to an open pitch, and a second state in which the second side of the cable is in an adjusted position such that said string puller is in an adjusted position and said string is tuned to a second adjusted pitch different from said open pitch.
2. The device of claim 1 wherein said first actuator is a lower actuator such that said first adjusted pitch is a lowered pitch, and said second actuator is a raise actuator such that said second adjusted pitch is a raised pitch.
3. The device of claim 1 wherein said second actuator is a lower actuator such that said second adjusted pitch is a lowered pitch, and said first actuator is a raise actuator such that said first adjusted pitch is a raised pitch.
4. The device of claim 1 wherein said first actuator is a lower actuator such that said first adjusted pitch is a first lowered pitch, and said second actuator is a lowered actuator such that said second adjusted pitch is a second lowered pitch different from said first lowered pitch.
5. The device of claim 1 wherein said first actuator is a raise actuator such that said first adjusted pitch is a first raised pitch, and said second actuator is a raise actuator such that said second adjusted pitch is a second raised pitch different from said first raised pitch.
5. The device of claim 1 further comprising a first stop coupled to said first side of the cable which stops the movement of the first cable at its normal position, and a first adjustable pitch stop which stops the movement of the first cable at its adjusted position, said first adjustable pitch stop being adjustable to adjust the adjusted pitch of the string caused by the first actuator.
6. The device of claim 5 further comprising a second stop coupled to said first side of the cable which stops the movement of the first cable at its normal position, and a second adjustable pitch stop which stops the movement of the second cable at its adjusted position, said second adjustable pitch stop being adjustable to adjust the adjusted pitch of the string caused by the first actuator.
8. A stringed musical instrument comprising:
a head end and a tail end;
a plurality of strings extending from said head end to said tail end, the tail end of each string being attached to a pitch adjusting device comprising:
a pivotable string puller which pivots about a first axis, said string puller having a string support surface upon which the string rests, wherein pivoting of the string puller adjusts the pitch on the string;
a pulley rotatably mounted on said string puller which rotates about a second axis which is spaced apart from said first axis;
a cable wrapped around said pulley, said cable having a first side of the cable extending from a first side of said pulley and a second side of the cable extending from a second side of said pulley, wherein movement of said first side of the cable causes said pulley to move thereby causing the string puller to pivot in a first direction, and movement of said second side of the cable causes said pulley to move thereby causing the string puller to pivot in a second direction;
a first actuator operably coupled to said first side of the cable, said first actuator configured to actuate to move said first side of the cable between a first state in which the first side of the cable is in a normal position such that said string puller is in a normal position and said string is tuned to an open pitch, and a second state in which the first side of the cable is in an adjusted position such that said string puller is in an adjusted position and said string is tuned to a first adjusted pitch different from said open pitch;
a second actuator operably coupled to said second side of the cable, said second actuator configured to actuate to move said second side of the cable between a first state in which the second side of the cable is in a normal position such that said string puller is in a normal position and said string is tuned to an open pitch, and a second state in which the second side of the cable is in an adjusted position such that said string puller is in an adjusted position and said string is tuned to a second adjusted pitch different from said open pitch.