Barbara T. Nessinger, Chief Editor
Casters, carts and tuggers are often regarded as materials handling basics; they rely on wheels and move product from one place to another. However, manufacturers of these warehouse workhorses continue to innovate. Manufacturing facilities are continuously looking to get leaner, while also meeting the increasing expectations for mass customization of products. Added to those challenges is an aging workforce and difficulty attracting and retaining qualified workers. One solution is the implementation of a designed, lean material flow system. And, that means improving how the materials are moved on the floor.
Suppliers continue to design new products that can make operations more efficient; reduce noise levels; and even improve safety/ergonomics. Such innovations require less effort, as operators transport goods from warehouses to assembly lines and then to finished goods warehouses. Due to the rise in product volume being seen in U.S. industry, plus an increase in demand for faster shipments, workers are at higher risk than ever for injuries, due to heavy loads that are being moved more quickly and more frequently. So, let’s have a look at what’s new and innovative in casters, carts and tuggers.
A rise in product volume, along with an increase in demand for same-day or next-day shipments, has caused a bit of a dilemma for U.S. warehouses. On the one hand, higher volume and demand leads to a higher net profits. However, it can also lead to higher employee injury risks, as distributors move heavier loads with more frequency.
Casting Off the Old Caster
In the workplace, the true function of casters is often taken for granted. They exist to move loads from one location to another, whether on fixed rails, via a tug or even manually. However, using the wrong caster can put workers at risk: A carefully-chosen caster wheel can make the workplace safer.
To lower the risk of injury, end-users can utilize specially designed casters that can withstand the weight of high product volumes. This also decreases the sounds the carts make as they move through the plant and warehouse. Workplace noise is considered a workplace hazard, so many manufacturers seek ways to decrease its impact on the factory floor and at warehouses.
For example, motorized industrial casters help to improve the ergonomics of moving a cart within a manufacturing process. Some manufacturers have added motors to their caster wheels; this method is fairly effective. However, integrating a caster into a motorized system can be complex. A shaft connects the motor to the wheel, resulting in a design that is not only complicated, but can be difficult to apply in most applications. The wheel has to be driven by a shaft; this shaft design is difficult to integrate in the function of the cart, often leading to a costly, intricate system.
But, there is hope. The integration of a quarter- or half-horse power electric motor with an industrial caster—without a shaft—simplifies both the design and integration of the product into the system. This all-in-one type caster can move loads of up to 6,000lbs at five mph. And, it can be operated safely by a control system specifically designed for the application.
Another option is a different type of swivel caster. Traditional carts have two swivel casters located at the steering end and two rigid casters at the opposite end. One of the issues operators face with this type of configuration is that when a cart is stopped and then restarted to a new position, the swivel casters can be pointed in two different directions, making it difficult to move. A new type of swivel caster has been patented that rotates around two separate, vertical axels. This minimizes a lockup often seen in conventional casters. This means it takes less strength/effort to start the cart’s movement and less frequent need to realign swivel casters that get repositioned incorrectly. This can help reduce workplace injuries and save time. The swivel construction inside the caster is the key. Casters of the past have a circular ball that rotates around a stationary center, but the new type of caster rotates around two separate vertical axels. This rotation minimizes the lockup tendencies, because they are no longer fighting against one another. Therefore, it takes less human effort to start moving a parked cart—resulting in a potential reduction in injuries. In addition to injury prevention, operators will also save another valuable resource: time. Time savings always means greater efficiency.
Carts and Tuggers Save the Day
Today’s tuggers and carts have evolved; they can be flexibly engineered to support some, or even all, of a manufacturing facility’s handling needs. One prevalent trend has been to replace forklifts in many production areas with cart-and-tugger systems, often customized for a warehouse’s individual needs. Tuggers and carts, compared to forklifts, have easy maneuverability in tight aisles and corners. Forklift extensions can be potential safety hazards in tight spots.
Both manned and unmanned tuggers work with powered and non-powered carts in a limitless range of configurations. Their features and flexibility allow these systems to address production complexities previously only handled by fork trucks. Fork trucks can be limited to the perimeter of a facility, for shipping/receiving and inventory placement into and out of racks. This can help increase the safety of warehouse personnel.
A tugger-and-cart system can replace one-load-at-a-time deliveries by fork trucks to the production floor in manufacturing plants by acting as trains or a linked series of multiple carts. They can handle multiple loads in one trip. The carts themselves may be loaded by a fork truck, but a tugger handles deliveries. However, unlike a fork truck, AGV-style tugs travel along a pre-determined route at a limited speed. Driven, or manned-style, tug operators have greater driver visibility—because the loads trail behind instead of riding on elevated forks in front of the driver.
Carts have evolved into specialized tools used in engineered processes to move materials as efficiently as possible. The more frequent delivery of smaller lots, in sequenced cart orders, is one response to the complexity of mass customization. Building multiple product lines on the same production floor or offering a selection of options to customize a standard product requires the flexibility carts can bring. Moreover, an AGV tugger or cart is usually equipped with laser-based, fully programable sensors that can warn of an obstacle in the vehicle’s path, thus ensuring the safety of materials on the floor—and most importantly— employees in the vicinity. WMHS