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Advanced Safety Features on Vertical Reciprocating Conveyors

Advanced Safety Features on Vertical Reciprocating Conveyors

Safety features on vertical reciprocating conveyors like PFlow Industries' M Series keep the materials and workers in a facility safe.

Vertical reciprocating conveyors (VRCs) offer an efficient way of moving materials, pallets, and heavy objects from one floor level to another. VRCs significantly increase safety in busy work environments when compared to forklifts and other manual material moving methods, due to their enclosed carriage structures.

However, like all things heavy and mechanical, VRCs can present significant safety hazards if not designed with safety features such as safety cams, limit switches, and gates/enclosures.

PFlow Industries takes safety very seriously. Since day one, PFlow’s dedication to VRC safety research and development has ensured that our products meet and/or exceed code requirements. Our rigorous testing and robust R&D programs have led to several patented safety innovations that we incorporate into or offer as options on all of our VRC products.

Let’s review VRC safety features that help to safeguard people and materials.

Snap Chain

A snap chain is the minimum guarding required by code for defining the carriage load ends. This safety device defines the carriage’s load/unload or non-enclosed side(s). PFlow offers several snap chain upgrades including safety gates, drop bars, and light grids.
snap chain

Diagonal Drop Bar

PFlow diagonal drop bars visually define the carriage loading point. Drop bars are either welded or bolted directly onto the carriage deck and side supports. An integrated gas shock prevents the bar from sudden pop-ups and drops. Drop bars can also be proofed, preventing the carriage from moving unless the bar is securely in place.
Diagonal drop bar

Safety Gates

ASME B20.1 Code regulations specify that each VRC must be equipped with a safety gate that’s mechanically interlocked with the carriage movement. PFlow safety gates are space efficient, built for maximum protection and performance, and equipped with a mechanical lock and electric contact. All PFlow safety gates meet code requirements for manual loading applications.

We offer three different single, bi-parting, and bi-panel types of safety gates:




Vertical Acting

vertical acting


Enclosure panels are required by code for all accessible sides of a VRC that are not used for loading or unloading. The enclosure must be at least 8’ high and capable of rejecting a ball 2” in diameter at each level. An enclosure panel is not required if a wall protects the side.

PFlow enclosure panels are 6” to 5’ wide and constructed out of ½” flattened expanded metal. We can design and manufacture non-standard sizes, custom finishes, and galvanized panels upon request.


Structural Steel

The structural steel used in any VRC is essential to ensuring the safety and longevity of the lift. PFlow VRCs use a 3:1 stress-over-yield safety factor and come with a lifetime structural warranty, which is the best in the industry.

Chain Tensioner

Chain tensioners utilize a limit switch assembly to monitor chain tension. If the chain becomes too slack or tight, the limit switch gets tripped and cuts power to the motor while extending the safety cams.
chain tensioner

Safety Cams

PFlow incorporates safety cams into all of our mechanical VRCs. In the unlikely event that the lifting chain should break, the safety cams will automatically and immediately rotate into position. The downward pressure of the carriage will force the cams into the guide column flanges and directly prevent carriage descent.
safety cams

Twin Roller Guides

This safety feature helps ensure reduced carriage movement at floor levels and smooth chain spooling. Twin Roller Guides are standard on all M, MQ, 21 Straddle, and F Series lifts.

PFlow’s Twin Roller Guides are designed for ease of maintenance as each bearing-free, Nyloil® cast nylon roller wheel has built-in oil lubrication.

twin roller guides

In addition to providing superior durability and performance compared to a traditional phenolic wheel with bearings, Nyloil® cast nylon roller wheels require less maintenance and installation time.

For extremely heavy loads, the Nyloil® Twin Roller Guides are replaced with steel guides.

Limit Switches

Travel of PFlow mechanical VRC carriages is controlled by a limit switch. When the switch is tripped or power is lost, the motor shuts off and the mechanically actuated brake engages.

Velocity Fuses

On hydraulic VRCs, velocity fuses regulate the flow of hydraulic fluid in and out of the cylinders. This safety feature ensures that in the event of a hydraulic line break or cylinder failure, the flow of hydraulic fluid is limited to prevent uncontrolled carriage descent.

Overload Sensors

PFlow VRCs are designed to address potentially unsafe situations, such as an inadvertently overloaded lift. We include a control relay that monitors motor current. If the current exceeds the amount required to lift or lower the maximum load, the unit shuts down and engages the brake.


Maintenance Pins

Manually actuated maintenance pins will lock the carriage in place when workers service the equipment. For an increased level of safety, PFlow can electronically proof the pins in place.

Decklock Safety System

The PFlow patented DeckLock Safety System prevents unintended carriage descent if inadvertently overloaded beyond maximum weight capacity or if the brake malfunctions while loading. We offer this critical safety feature in pneumatic, electric, and gate-operated versions.
maintenance pins

Maintenance Mode

Maintenance Mode ensures authorized personnel can safely enter the area under a raised carriage platform to perform cleaning or lift maintenance. The maintenance mode feature is activated from the main control panel via a key. When maintenance mode is engaged, all gates and push button stations are deactivated to avoid accidental use. The carriage then travels to the upper level, the DeckLocks extend and the carriage lowers to rest on the DeckLocks. Once proper lockout/tagout procedure is activated, authorized workers can work beneath the secured carriage.

PFlow leads the Industry in VRC Safety. Our innovative and robust safety features ensure safe material handling in factories, warehouses, industrial plants, or anywhere that goods need to be moved from one level to another. Our unwavering commitment to safeguarding workers and materials helps ensure a more secure material-handling experience.

Choose PFlow and enjoy peace of mind with our VRCs that are guaranteed to meet code in all 50 states. Click below to discover the value you’ll get with a PFlow material lift.