Better Gas Winch

grabcad

In my Gas Winch 1.0, I realized improvements were necessary. My goals for the upgraded model include: providing a less fussy latch/release mechanism, enhancing the outer appearance, and offering servo release. To achieve modular design, each gas spring unit fits within a 2"X2"X1/16" wall square tube. The current configuration provides 48 inches of winch travel with 275 pounds of force in a 2"X4"X32" package. Alternatively, an 8-inch stroke gas spring can be used for a longer overall height but still offering 32 inches of winch travel at up to 275 pounds of force. Lighter options include stacking three 8-inch stroke gas springs for reduced overall length with 48 inches of winch travel. However, this would weigh 50% more than the dual 12-inch configuration. Another option is arranging the 3 gas spring units in an "L" shape, each leg measuring 4 inches for a bounding box of 2"X4"X24". Servo release should be fine if bearing performance meets expectations, requiring two mini-servos to release each gas spring. Powering the servo to relatch is necessary after compressing the gas springs. The net unlatch/relatch torque is approximately the same, with 550 pounds of force in unlatch and 825 pounds of force in relatch but with a smaller moment arm. Hitec servos are recommended for their stall torque at 6V. Manufacturing parts involves 3D printing for ease and some complex machined parts like the bottom block and top pulley housing, made primarily from aluminum or steel. Latch bearings use 5905K210_STL needle-roller bearings with a static load rating of 470 pounds, supporting 550 pounds of maximum load share by two bearings. Thrust bearings are 5909K320_THRUST needle-roller bearings with dynamic load ratings over 2000 pounds, suitable for 825 pounds compression force. Pulley bearings use 60355K505_BALL bearings, with some concern about the bottom pulley's 535 pounds static rating; however, a 730 pounds static rated bearing is an option. Finally, screws run up and down the outside of the 2"X2" tube to guide a "truck" for lifting hooks or other mechanisms. Updates include adding actual gear teeth to servo gear and unlatch tube, reducing the gap between latch roller and latch plate, changing the bottom block to an integral axle, and considering larger bottom pulley bearings. Still to be completed are putting in remaining screws, CAD of servo spline and servo screw, creating 8-inch and 16-inch travel versions, and uploading a new ZIP file.