Overview
Off-center loads tilt standard VRC carriages. Tilted carriages stress guide rollers, misalign gates, and create unstable loading and unloading conditions. The PFlow 21 Series solves this problem with a synchronized overhead torsion bar that mechanically links the two hydraulic cylinders, forcing both sides of the carriage to travel at the same speed at all times. The result is a level carriage throughout the full range of travel — regardless of where the load sits on the platform.
The 21 Series is available in straddle or cantilever configurations for indoor or outdoor use, with carriages large enough to accommodate full-size pallets and bulky materials up to 12 feet wide by 10 feet long.
Specifications
- Capacity: up to 6,000 lbs (based on carriage size and options)
- Carriage: up to 12 ft wide x 10 ft long
- Vertical rise: up to 22 ft
- Speed: 24 fpm standard, up to 30 fpm available
- Cycle rate: 10 cycles per hour, 100 per day
- Configurations: straddle or cantilever
- Environment: indoor or outdoor
- Warranty: lifetime structural warranty
- Compliance: ASME B20.1 Safety Standards
Synchronized Torsion Bar System
The 21 Series’ defining feature is its overhead synchronized shaft. The carriage is lifted and lowered by chain over sprocket, with sprockets mounted on an overhead shaft that mechanically links the two guide-column-mounted hydraulic cylinders. This torsion bar forces both cylinders to move at the same rate, keeping the carriage level throughout travel — even when the load is positioned to one side. This is not an electronic leveling correction. It is a mechanical linkage that prevents tilt from occurring in the first place.
Safety Features
The 21 Series includes comprehensive built-in safety systems.
- Certified safety cams prevent carriage descent in the unlikely event of chain failure
- Velocity fuses prevent uncontrolled descent if a hydraulic hose ruptures
- Check valves hold the carriage in place during power loss
- Pressure switch prevents drifting or sinking for stable loading and unloading
- Manual lowering valve for emergency carriage descent
- Optional DeckLock safety system provides added security at upper levels
- Interlocked gates at each level with gate status switches
Installation and Options
The remote-mounted control panel and hydraulic pump are pre-wired and ready for immediate installation. Optional quick-connect cabling for push-button stations and gate interlocks reduces field wiring costs. For outdoor or wash-down environments, optional hot-dipped galvanized or epoxy finish is available. Explosion-proof components can be specified for classified (hazardous) environments.
Applications
The 21 Series serves warehouses, distribution centers, manufacturing facilities, self-storage, archives, and any two-level application where loads vary in weight and placement. Its indoor and outdoor capability makes it practical for loading docks, exterior mezzanines, and covered outdoor areas where other VRCs cannot operate. The large carriage size accommodates full-size pallets, carts, and bulky equipment.
PFlow 21 Series vs. Wildeck Hydraulic VRCs
Both are two-post hydraulic VRCs for single-level transfer. The PFlow 21 Series is differentiated by its synchronized torsion bar that mechanically keeps the carriage level regardless of load placement, its higher capacity ceiling (up to 6,000 lbs vs. 4,000 lbs for Wildeck hydraulic), its larger maximum carriage (12′ x 10′), and its standard indoor/outdoor capability. Wildeck hydraulic VRCs feature the patented AutoSenz® M-Series overload detection and a modular bolt-together design. Choose based on capacity, environment, load-leveling requirements, and preferred safety features.