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3-Ton Heavy-Duty High-Speed Vertical Reciprocating Conveyor (VRC): Enabling 60 Pallets/Hour High-Frequency Throughput for Intelligent Logistics in China

Project Overview

The client for this project is a large-scale modern intelligent manufacturing logistics and warehousing center in China. The facility faced severe vertical transport bottlenecks of heavy palletized materials across multiple floors (lifting height of 15.5 meters, with 3 stops and 3 stations). Traditional freight elevators were too slow and could not integrate seamlessly or continuously with automated roller conveyor lines and ground-level manual pallet trucks.

To resolve this inter-floor logistics bottleneck, we customized and deployed two sets of 3-ton SJW3.0-15.5 Vertical Reciprocating Conveyors (VRC) . The core highlights of this project include:
1. Ultra-High-Speed Throughput: A lifting speed of up to 60 m/min (variable frequency adjustable) , achieving a high continuous throughput of 60 pallets/hour over a 15.5-meter vertical span .
2. Innovative Pit-Recessed (Buried) Roller Conveyor: The ground floor conveyor features a recessed pit-mount installation (roller surface sits flush with the warehouse floor) with built-in channels designed specifically for manual hand pallet jacks . This allows operators to load 3-ton pallets directly using standard manual pallet jacks, completely eliminating the need for expensive transition tables or heavy forklifts.
3. Elevator-Grade High-Fatigue Resistance: Built to last over 15 years , the mast utilizes high-strength 150x150x4mm square steel columns and professional T90 elevator guide rails, providing superb structural rigidity under high-cycle dynamic loads

Challenge & Solution

Challenge

Prior to deploying our equipment, the warehouse’s vertical logistics setup suffered from severe operational and engineering bottlenecks:

Incredibly Low Vertical Throughput: The facility previously relied on traditional, slow freight elevators (6–9 m/min), requiring manual door operation and forklift wait times. The average round-trip cycle per pallet took 10–12 minutes, limiting throughput to only 25 pallets/hour. This created constant raw material starving for the upstairs mixing and packaging lines.
Inability of Hand Pallet Jacks to Direct-Load Conveyors: Standard automated roller conveyors are typically at least 300mm high. Operators using manual hand pallet jacks could not lift and deposit 3-ton pallets directly onto these conveyors. Standard solutions required deploying heavy, counterbalanced warehouse forklifts indoors, which consumed tight aisle space and increased dust and exhaust emissions.
Structural Deflection and Shaking Under Heavy Dynamic Load: Moving a 3,000kg payload at 60 m/min with continuous start-stop actions (approx. 1 cycle/minute) generates immense dynamic forces. Standard lifting structures lacked the rigidity to absorb these shocks, resulting in steel fatigue, guide rail warping, and leveling errors exceeding ±10mm.
Terminal Over-Travel (Over-running) and Fall Risks: At high travel velocities, any failure of the limit switches or dynamic chain fatigue posed a catastrophic risk of cabin over-running or free-falling, threatening warehouse personnel and high-value materials.

Solution

In response to the client’s pain points, we customized and delivered a high-rigidity, fully automated turnkey VRC engineering solution :

30kW High-Power VFD Drive & Heavy-Duty Frame: The lift is powered by a 30kW SEW/Nord braked geared motor, controlled by a Siemens SIMATIC S7-1200 PLC and premium variable frequency drives . By optimizing the VFD speed S-curve, we achieved “soft-start and soft-stop” profiles, eliminating mechanical impact at a high velocity of 60 m/min . The mast structure is fabricated from 150x150x4mm high-strength square tubing and T90 elevator guide rails, ensuring zero visible deflection under a 3-ton concentrated load .
Innovative “Pit-Recessed” Conveyor Allowing Hand Pallet Jack Loading: At the ground station, the conveyor is installed inside a shallow concrete pit so the roller surface sits flush with the shop floor . The conveyor tracks feature recessed slots designed specifically for manual hand pallet jacks . Operators can push standard pallets in and drop them onto the tracks without requiring expensive transitional lift tables or forklift transitions.
Elevator-Grade Overspeed Governor & Safety Gear Linkage: The cabin is integrated with a professional XJ24B safety gear and XJ33/XJ34 overspeed governor system [50]. If descending velocity exceeds safe limits or chain tension (Donghua 20B chain) is compromised, the overspeed governor mechanically trips, forcing the safety gear to instantly lock the 3-ton cabin to the T90 guide rails . The pit floor is fitted with heavy-duty XJ80 rubber buffers for reliable impact absorption .
Landing Zonal Barrier & Interlocked Rapid PVC Doors: All three floor stations feature automated, high-tensile yellow PVC rapid doors with transparent vision windows . These doors are fully interlocked with the Siemens PLC. The PVC doors only roll open once the platform achieves a precise level within a $\pm 5$ mm tolerance [49], effectively isolating dust and noise between floors during travel.

Technical Specifications

No.	Engineering Parameter	Technical Specification & Brand Configuration
1	Equipment Model	SJW3.0-15.5 Heavy-Duty Vertical Reciprocating Conveyor (VRC)
2	Rated Load Capacity	3,000 kg (3.0 Metric Tons)
3	Vertical Lifting Velocity	60 m/min (Variable Frequency Adjustable)
4	Lifting Stroke Height	15,500 mm (15.5 Meters)
5	Hoist Drive Power	30 kW / 380V / 50Hz Geared Brake Motor (SEW / Nord)
6	Horizontal Conveyor Speed	15 m/min
7	Conveyor Drive Power	2.2 kW / 380V / 50Hz Geared Motor (Nord / Taibang)
8	Cabin Inner Dimensions	2,200 mm (W) x 2,000 mm (D) x 2,200 mm (H)
9	Landing Stations & Stops	3 Stops, 3 Stations (C-Type same-side configuration)
10	Lifting Positioning Accuracy	± 5 mm (Closed-loop photoelectric and inductive alignment)
11	Automation PLC Controller	Siemens SIMATIC PLC Systems
12	Variable Frequency Drive (VFD)	Siemens / Yaskawa Frequency Inverter
13	Human Machine Interface	10-inch Touchscreen HMI (Kunlun Tongtai)
14	Main Mast Steel Columns	$150 \times 150 \times 4 mm$ High-Strength Square Tubing (Laiwu Steel)
15	Cabin Guide Rails	Professional T90 Elevator-Grade Guide Rails (Shentong)
16	Heavy-Duty Lifting Chain	20B High-Strength Roller Chain (Hangzhou Donghua)
17	Fail-Safe Mechanism	Safety Gear (XJ24B) + Overspeed Governor (XJ33/XJ34) Linkage
18	Landing Safety Barrier	PVC Rapid-Roll Doors (Yellow PVC with transparent vision window)
19	Ground Floor Interface	Pit-Recessed Roller Conveyor (Designed for manual hand pallet jacks)
20	Sensors & Low-Voltage Electrics	Omron/SICK Photoelectric Sensors & Schneider Contactors
21	Design Service Life	$\geq 15$ Years (Continuous high-frequency cycle operation)

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Gradin Machinery is a leading manufacturer specializing in aerial work platforms and hydraulic lifting solutions. With ISO & CE certifications, we provide safe, reliable, and customized equipment for global industrial needs

Need a Technical Advice?

3-Ton Heavy-Duty High-Speed Vertical Reciprocating Conveyor (VRC): Enabling 60 Pallets/Hour High-Frequency Throughput for Intelligent Logistics in China

Project Overview

Challenge & Solution

Challenge

Solution

Technical Specifications

Project Gallery

Have a question or need technical advice? Our team is available 24/7 to assist you

Get a Bespoke Engineering Proposal

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