Lift Type Advantages
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Advantages/disadvantages of lift drive styles.
Most lifting devices are driven by one of three styles of lifting mechanisms. Hydraulic, ball screw or roller chain drives.
Chain drives offer the greatest advantages when you weigh in strength, safety, cGMP and versatility.
Ball screw lifts
Ball screws have very low backlash. Lifts are always biased down due to gravity so this doesn’t offer much of an advantage.
High mechanical efficiency. 90 percent efficient is typical.
Ball screws can be positioned within 0.0001″ of linear travel when driven by a servo motor. This precision is necessary for machining centers a linear actuators. Ball screws are expensive.
If the ball return system fails, the balls fall out and the lift drops rapidly.
Whip is a major issue with ball screws. On every cycle of travel, a lift will experience a resonance and the screw will whip. Some screws only last 6 months, some a couple of years. Ball screws are very difficult to change out. Some ball screw lifts changed out entirely with hydraulic or chain drive lifts in place of repairing them. This leads to buyers remorse. Ball screw drives are best suitable for short travel drive applications like grippers and precise horizontal travel where the cost is reasonable and the event of failure is not catastrophic.
Hydraulic powered lifts
Hydraulic cylinders offer extreme lift capacity is a very compact space. A hydraulic cylinder can easily lift 50,000 pounds.
The hydraulic reservoir tank grows in proportion to lift height. When a lift gets tall, you need a very large tank on the back of the lift.Hydraulic lifts drift.
If you leave your load in at an elevation overnight, you may find it lowered onto your process equipment by morning, causing damage. External dead stops can be used to remedy this, but they are not versatile and some do not consider them cGMP due to cleaning issues.
Hydraulic systems are very mechanically inefficient. Hydraulic systems are messy to work with eventually leak. Many specifications for cGMP areas forbid the use of hydraulics.
Chain drive lifts
Chains have high load bearing capacity.
Roller chains are extremely efficient at approximately 98 percent efficiency.
Roller chains are extremely durable.The price of a roller chain system is a fraction of other drive systems.Many chains are not suitable for lifting applications.
Some manufacturers of chain lifts use incorrect chain which can lead to failures.Undersized chains stretch over time. Chain lifts do not drift over time. When they are stopped in any elevation, they will stay at that elevation.
Chain drive systems are extremely versatile. Any load capacity or drive speed can be achieved with the proper engineering.
Chain drives are safe. If a 2,000 pound lift capacity is required, a 20,000 pound chain is supplied, and a drive system that can only exert 2,200 pounds of force, the chain can not fail. The drive circuit will fault and system will require a reset.Chains have a long life cycle with low maintenance.
The life cycle and durability are largely dependent on engineering practices.
Chain drive lifting systems are the preferred method of lifting loads when proper engineering is applied.
Features
Features
Most lifting devices are driven by one of three styles of lifting mechanisms. Hydraulic, ball screw or roller chain drives.
Chain drives offer the greatest advantages when you weigh in strength, safety, cGMP and versatility.
Repurposing
Post Material Handling Post Lifts may be bought back for repurposing when its original design function is no longer applicable. Repurposing was one of the major design criteria when the Post Lifts were originally conceived.
Repurposing reduces waste, adds reselling value and is the responsible means to recycle equipment.
Virtual Reality Demo
Post Virtual Reality develops proposals and building layouts using state of the art Virtual Reality visualizations.
We will build your layout in 3D and make it available to you using a standard web browser. The same VR environment can be viewed in browser on your desktop or laptop computer, a head mounted display and cell phone.
Post Virtual Reality converts CAD data into 3D presentations. If you do not have 3D CAD data, we will model your equipment and layouts for you.
Here’s What Our Client’s Are Saying
“We have teamed up with Post for over 9 years on several successful projects. Pat and his team are very knowledgeable and are able to supply solutions that integrate perfect with our machines.
Not only are their material handling solutions very well manufactured, I am especially grateful for the attention to detail and automation expertise at Post. They are problem solvers and a terrific resource for all material handling projects.”