Large Rocker Hand Crank Winch Model 70 for Greenhouse Sidewall Roll Up Description This manual roll up lifting device is a large rocker style hand crank winch designed specifically for agricultural sidewall film and greenhouse window opening. Model 70 provides reliable manual control and a self locking mechanism so sidewalls and windows stay precisely where you set them without slipping. Key benefits Precise manual control: Smooth hand crank operation lets you open and close sidewall film or windows with fine adjustment for ventilation and light control. Reduced effort: The rocker winch design multiplies crank power for easier lifting and rolling of heavy film or curtains. Secure position holding: Builtin self locking device prevents unintended movement so vents and sidewalls remain stable under load. Wide compatibility: Designed for use on farm and ranch greenhouses, hoop houses, and other agricultural sidewall systems that use roll up film or curtains. Durable performance: Engineered for repeated manual operation in agricultural settings. Features and important attributes Function: Manual roll up lifting and window opener via hand crank; self locking mechanism for secure holding. Mechanism type: Large rocker style winch for greater mechanical advantage during manual operation. Model: 70. Typical applications: Sidewall film roll up, greenhouse window opening, manual curtain lifting for vents and shade. Installation: Mounts to greenhouse frame or support post for direct drive of roll tube or shaft. Compatible with common greenhouse sidewall systems and window frames. Operation: Designed for repeated manual use with controlled, reversible crank action. Practical use scenarios Daily ventilation control: Use the winch to open sidewall film in the morning for airflow and close in the evening to retain heat and humidity levels required for crops. Storm or cold weather response: Quickly roll down and lock sidewalls before wind or temperature drop to protect plants and maintain microclimate. Shade and light management: Adjust roll up curtains midseason to control light exposure or manage shading during peak sun hours. Why customers choose this unit Straightforward manual operation that requires no power source and is easy to maintain. Self locking design minimizes the need for constant monitoring or readjustment. Robust rocker mechanism reduces physical strain when lifting heavier film or curtain assemblies. Versatile for use in a variety of agricultural structures including farm and ranch greenhouses. What to check before buying Confirm Model 70 mounting dimensions and shaft compatibility with your existing roll tube or frame. Ensure the winch mounting location provides proper alignment for smooth roll up and release. Verify the expected load and curtain weight to match manual operation capacity. This Model 70 hand crank winch is a practical, mechanical solution for reliable manual opening and closing of greenhouse sidewalls, windows, and roll up curtains on farms and ranches.