WINCH WITH MULTIPLE SPOOLS ON SINGLE DRIVESHAFT
A winch is described that includes a motor and a driveshaft coupled to the motor for rotation about its axis. A first and second spool are mounted to the drive shaft so that rotation of the driveshaft causes rotation of the first and second spool. A first line is attached to the first spool and a second line is attached to the second spool. First and second line guides are configured to wind the lines in a helical path on the respective spools when the driveshaft is rotated in one direction and to unwind the lines from the helical path when the driveshaft is rotated in an opposite direction. Each line guide is further configured to translate axially along the first spool to facilitate winding and unwinding along the respective helical path.
1 . A winch comprising:
a motor;
a driveshaft having an axis and being coupled to the motor wherein the motor rotates the driveshaft around the axis,
a first spool on the driveshaft, wherein rotation of the driveshaft causes rotation of the first spool;
a second spool spaced apart axially from the first spool on the driveshaft, wherein rotation of the driveshaft causes rotation of the second spool;
a first line attached to the first spool;
a first line guide configured to wind the first line in a first helical path on the first spool when the driveshaft is rotated in one direction and to unwind the first line from the first helical path when the driveshaft is rotated in an opposite direction, wherein the first line guide is further configured to translate axially along the first spool to facilitate winding and unwinding along the first helical path;
a second line attached to the second spool; and
a second line guide configured to wind the second line in a second helical path on the second spool when the driveshaft is rotated in the one direction and to unwind the second line from the second helical path when the driveshaft is rotated in the opposite direction, wherein the second line guide is further configured to translate axially along the second spool to facilitate winding and unwinding along the second helical path.
2 . The winch of claim 1 , wherein the first spool can be moved axially and fixed at different positions along the driveshaft and further comprising a first spool lock to lock the first spool at the different positions along the driveshaft.
3 . The winch of claim 2 , wherein the second spool can be moved axially and fixed at different positions along the driveshaft and further comprising a second spool lock to lock the second spool at different positions along the driveshaft.
4 . The winch of claim 3 , wherein a cross-sectional shape of the driveshaft and a cross-sectional shape of the first and second spools are selected to allow axial movement of the first and second spools along the driveshaft but prevent rotation of the first and second spools relative to the driveshaft.
5 . The winch of claim 4 , wherein the cross-sectional shape of the driveshaft includes at least one depression and the cross-sectional shape of the first and second spools includes at least one protrusion corresponding to the at least one depression.
6 . The winch of claim 4 , wherein the cross-sectional shape of the first and second spools includes at least one depression and the cross-sectional shape of the driveshaft includes at least one protrusion corresponding to the at least one depression.
7 . The winch of claim 1 , wherein the first and second line guides each comprise a tensioning wheel configured to frictionally engage the first line and second line, respectively, and thereby apply tension to the first line and second line, respectively, as they are unwound, and wherein the tensioning wheel is driven by the motor.
8 . The winch of claim 7 , wherein each tensioning wheel is driven by the motor so as to have a tangential speed at least 5% greater than the linear speed of the line it engages as the line is being unwound, and wherein the first tensioning wheel further comprises a one-way bearing between the tensioning wheels and the motor, whereby each tensioning wheel can be rotated by its engagement with the line as it is being wound.
9 . The winch of claim 8 , further comprising a rail with an axis of rotation parallel to the axis of the driveshaft, and wherein the rail is rotated by the motor.
10 . The winch of claim 9 , wherein the first one-way bearing is located between the first tensioning wheel and the rail and wherein a second one-way bearing is located between the second tensioning wheel and the rail.
11 . The winch of claim 9 , further comprising a gear on the driveshaft and a cog on the rail that engages the gear, and wherein the size of the gear and the size of the cog are selected to cause the tangential speed of the tensioning wheels to be at least 5% greater than the linear speed of the line it engages as it is being unwound.
12 . The winch of claim 7 , wherein each of the tensioning wheels comprises a compressible outer surface to aid in gripping the lines.
13 . The winch of claim 1 , wherein each of the first and second spools comprise a helical groove to receive the first and second lines, respectively.
14 . The winch of claim 1 , wherein the first line guide is translated axially by engaging the helical groove in the first spool and the second line guide is translated axially by engaging the helical groove in the second spool.
15 . The winch of claim 1 , wherein the motor fits within a cavity in the driveshaft.
16 . The winch of claim 1 , further comprising a third spool on the driveshaft, a third line and a third line guide.
17 . A lifting system comprising a first winch as recited in claim 1 and a second winch as recited in claim 1 , and wherein the first and second winches are synchronized to lift and lower a single object with four lines.
18 . A winch comprising:
a driveshaft comprising an elongated body having a generally uniform cross-section along the elongated body;
first and second end plates rotatively mounted to the driveshaft at opposite ends of the driveshaft;
a motor within the elongated body and configured to cause rotation of the driveshaft in a first and second direction;
a plurality of spools around the driveshaft at various axial positions along the driveshaft, wherein the spools have a helical path carrying a line that winds onto the spools as the driveshaft is rotated in the first direction and unwinds off of the spools as the driveshaft is rotated in the second direction;
a line guide attached to the each of the spools, each line guide being configured to guide the line onto and off of the spools, each line guide comprising a tensioning wheel that contacts the line of each spool; and
a rail mounted between the end plates and being radially spaced apart from the driveshaft, wherein each line guide is coupled to the rail, and wherein the rail rotates in a direction opposite the direction of the driveshaft and causes the tensioning wheel to rotate in the direction to facilitate the line winding onto and off of the spools.
19 . The winch of claim 18 , wherein each tensioning wheel is rotated with a tangential speed at least 5% greater than the linear speed of the line it engages as the line is being unwound.
20 . The winch of claim 18 , wherein the tensioning wheels comprise a compressible outer surface to aid in gripping the lines