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Stage Winch Design Techniques. Motor Winch Physics. Dan Eslinger Assistant Technical Director Seattle Repertory Theatre. Sample Winch Design Application:. Wagon: 3000# Max velocity: 3.5 ft/sec Acceleration: 2 ft/sec 2. Rules of thumb: Velocity: 3 ft/sec standard top speed
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Motor Winch Physics Dan Eslinger Assistant Technical Director Seattle Repertory Theatre
Sample Winch Design Application: Wagon: 3000# Max velocity: 3.5 ft/sec Acceleration: 2 ft/sec2 Rules of thumb: Velocity: 3 ft/sec standard top speed 4 ft/sec for fast applications Acceleration: 1 ft/sec2 – 4 ft/sec2 Decide how long for it to reach top speed. Casters: 6” diameter soft rubber running on a flat wood deck.
N: normal force, perpendicular to motion, here: the load µr: caster’s coefficient of rolling friction hard rubber on wood: 0.003” soft rubber on wood: 0.008” rc: radius of caster Double the friction to be safe. Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters First, find the Force required to move the wagon: Forcetotal = Faccel + Ffriction + Flift
Size the Motor (hp): Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters Force to move wagon: 346.3# Round up to 3 hp motor. sample: 1750 rpm Size the Drum: at least 30 times the cable diameter. Choose 8” diameter drum.
reduction needed in sprockets Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters Force to move wagon: 346.3# 3 hp motor 1750 rpm 2.09’ per drum rev. Size the Reducer & Sprockets: match desired top speed (3.5 ft/sec) Choose 15:1 reducer. Drum sprocket teeth = 1.161 x reducer sprocket teeth. e.g. 12 teeth on reducer & 14 teeth on drum.
T: torque in ft lbs Force is great enough to move wagon! Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters Force to move wagon: 346.3# 3 hp motor 1750 rpm 2.09’ per drum rev. 15:1 Reducer 12 teeth – 14 teeth sprockets Verify Amount of Torque:
Compact Manual WinchLoren SchreiberTechnical DirectorSan Diego State University
Compact Manual Winch Price List Less Gears: $380
Jon Lagerquist Technical Director South Coast Repertory Theatre
Torque tamer (Dodge) with quick pins for disconnecting sprocket from shaft
Friction Drive Winch Chris Fretts Technical Director Indiana Repertory Theatre
Friction Drive Winch Motorized or manual operation Does not use a Grooved Drum Uses a keyed four groove Multi-sheave above and five idler sheaves below Cable is either an endless loop or both ends terminate at wagon
Drive: 2HP Motor with 25:1 Gear Reducer Motor Output: 1750 RPM Gear Reducer Output: 70RPM Top Cable Speed: 3ft./sec. Shafts: 13/16” Roller Chain: #50
Operation of the winch can be changed from motorized to manual by shifting the roller chain from the sprocket on the Gear Reducer to the idler sprocket on the motor mount. By pulling the lower pins on the mount and pivoting the motor mount on the upper bolts, the roller chain can be shifted to the idler.
A handle for manual operation can be attached to either end of the two shafts on the top of the winch unit. In its current configuration, we have installed a additional 1.5:1 output reduction with the installation of a 20 tooth and 30 tooth sprocket on the two top shafts. This allows some choice of mechanical advantage if the winch is operated manually. This additional reduction decreases the motorized top cable output to 2ft./sec.
Proper tension on the drive cable is controlled by drawing back the idler sheave assembly on the two threaded rods. This is done by using an impact wrench on the welded nuts on back end of each threaded rod.
A rotary encoder is attached with #25 roller chain and sprockets to the drive sheave to enable positioning control with our PLC system. This can be interchanged with a mechanical counter if needed for manual operation
Major Parts List Baldor # 2HP Motor #VM3558T ebay “Buy it now” price $120 25:1 Gear Reducer #GF2532BG ebay “Buy it now” price $199 Grainger # Pillow Blocks (4) #5X685 Multi-sheave 11.25”OD #2L371 Sheave 7”OD (5) #3X923 #50 Roller Chain 10’ #2W095 15 Tooth #50 Sprocket (3) Varies with Bore 30 Tooth #50 Sprocket # 6G021 www.surpluscenter.com Friction Drive Winch Indiana Repertory Theatre
Peter Pan Winch Developed and designed by Stephen Henson at California State University Fullerton with special thanks to Bill Meyer, Matthew McKinney and Scott Shiba for various creative influences during the process of development
Prototype winch -Form followed function purely -Used with a sprocket instead of three-grooved sheave, for direct chain-drive -Two plates punched to be bolted to the gear box, welded to a cross member punched for hangers Version 2.0 winch -Rotated motor 90 degrees -Added two vertical angle irons for pushing motor away from batten -Allowing for three-grooved sheave with a double sheave hung above directly from batten (not shown) -Crudely mounted mule blocks for directing cables along batten to scenery -Rotary Limit Switch and Junction box mounted to motor mount plate
-Top plate is designed to facilitate standard Batten hangers, as well as suspend a swivel double sheave -Slotted flat bars accommodate multiple positions for head blocks as well as twisting into alignment with three-grooved sheave -Center plates are punched accordingly for mounting gear box with encoder and motor suspended from gearbox -Bottom of frame has additional steel structure for mounting rotary limit switch and junction box containing RJ45 connectors. -Head block assembly is punched with extra holes to allow for flexibility with parts
Matthew McKinney Graduate Student San Diego State University
Frankenwinch • Traveler winch • Built from equipment on hand • 2HP AC Vector Motor • Drive Mounted to winch • Massively over powered (Opera Capable) • Cost: Priceless
Shipping Crate Top is removed to attach directly to batten and lift out of box
Bill Meyer Technical Director Cal State Fullerton
Basic 1 ½ HP DC Winch with dolly and strap • Frame design version 8ish • Setup to be used in either direction