Electric Manual Control Extendable Cantilever Storage Rack

Warehouse managers often face a trade-off: invest in fully automated storage systems that are expensive and complex, or rely on purely manual racks that require physical effort and slow down operations. Herochu bridges this gap with the Electric Manual Control Extendable Cantilever Storage Rack, a hybrid system that allows operators to choose between electric-powered extension or manual cranking. This dual-mode design ensures continuous operation even during power outages or when working in areas without electrical service.

The Concept of Dual-Mode Cantilever Extension

Traditional extendable cantilever racks use either a hand winch or a fixed electric motor. Hand winches are reliable but slow, requiring dozens of turns to fully extend an arm under load. Electric-only racks become useless if the motor fails or if the rack is moved to a location without power. Herochu’s solution integrates both systems into a compact gearbox mounted at the base of each upright column.

The operator selects the mode via a mechanical clutch lever. In electric mode, a 24V DC motor (powered by a rechargeable battery pack or mains adapter) drives a planetary gear reducer. In manual mode, the operator inserts a folding crank handle into the same input shaft, disengaging the motor via a dog clutch. The same worm gear output drives the telescopic arm sections in either mode.

This dual-mode approach is particularly valuable for extendable cantilever storage racks used in remote storage yards, construction sites, or temporary warehouses where reliable power is not guaranteed. It also provides a low-tech backup for facilities that prefer to keep spare motors on hand rather than rely on service calls.

Telescopic Mechanism Design

Herochu’s extendable cantilever arms use a three-stage telescopic tube assembly. The fixed outer tube mounts to the upright column. Inside it, a middle tube slides on nylon rollers. The inner tube (which carries the load) slides inside the middle tube. A high-strength steel chain connects all three stages, wrapped around sprockets at the end of each tube. When the gearbox rotates a drive shaft, the chain pulls the inner and middle tubes simultaneously, achieving a total extension ratio of up to 2.5:1. For example, a collapsed length of 600 mm can extend to 1500 mm.

Critical to reliability is the load-holding brake. In electric mode, a spring-applied, electrically released brake holds the arm at any position. If power is lost, the brake automatically engages, preventing the arm from retracting under load. In manual mode, the worm gear itself is self-locking (lead angle less than friction angle), so the crank stays in place even if the operator releases it. However, Herochu still recommends using the provided locking pin for long-term static loads.

Manual Control Features for Precision

While electric extension is faster, manual control offers precision advantages. When positioning an expensive long load—such as an aluminum extrusion or a carbon fiber tube—operators often prefer the tactile feedback of a hand crank. The Herochu crank handle has a torque-limiting detent that clicks when maximum manual input torque (50 Nm) is reached, preventing overload. A built-in ratchet allows the operator to reverse direction without removing the handle.

The manual mode also serves as an emergency retraction system. If the electric motor fails with the arm fully extended under a 1000 kg load, the operator can engage the manual clutch and slowly lower the load by turning the crank in reverse. The worm gear’s high reduction ratio (60:1) makes this possible with reasonable effort—approximately 16 Nm of input torque to lower a full load, achievable by an average person.

Application Examples for Hybrid Operation

Consider a metal service center that stores steel tubes in lengths up to 12 meters. The main warehouse has 240V power, so the electric mode is used for routine put-away and retrieval. However, the center also has an outdoor yard where they store over-length materials. Instead of buying separate manual racks for the yard, they use Herochu’s dual-mode racks. When moved outdoors, the battery pack (good for 300 full extension/retraction cycles) powers the electric mode. If the battery drains, manual mode takes over without moving the load.

Another application is in aerospace component storage, where anti-static conditions and spark prevention are critical. Electric motors can generate sparks from brushes. Herochu offers a sealed, brushless DC motor option, but some facilities still prefer manual mode for sensitive areas. The dual-mode rack allows them to use electric mode in general storage zones and manual mode in explosive atmospheres, all within the same rack system.

Technical Specifications and Customization

Herochu builds the electric manual control extendable cantilever storage rack to order. Standard parameters:

The control system includes a wired pendant with emergency stop and a wireless remote as an option. For facilities with multiple racks, Herochu can integrate a central control panel that operates up to 32 racks from one station.

Installation and Commissioning

Each rack ships with pre-assembled upright frames, loose cantilever arms, and hardware kits. Herochu provides installation drawings showing anchor bolt locations and required floor flatness. Assembly time for a 5-level, double-sided rack with 10 arms is approximately 8 man-hours. The electric wiring is plug-and-play: each motor has a waterproof connector that mates to the control cable harness.

Certification includes SGS load testing and ISO 9001 manufacturing. The powder coating process includes a two-stage pickling treatment that creates an oxide film for superior adhesion, a feature Herochu claims no other manufacturer matches. This extends rack life in humid or corrosive environments.

Operational Benefits Summary

Switching from a purely manual extendable cantilever rack to Herochu’s electric manual control model typically reduces retrieval time by 65% for the electric mode while retaining 100% functionality during power failures. The dual-mode design also simplifies maintenance—if the motor fails, the rack remains usable until a replacement motor arrives. For warehouses seeking to future-proof their long-load storage, this hybrid approach offers the best of both worlds.