The Challenge
The vacuum lifter would be required to lift plastic, aluminum and foam sheet materials used in manufacturing refrigerated trailers. When these materials are lifted, it is crucial that distortion and buckling be kept to a minimum. Once the materials are processed into trailer cladding, the vacuum lifter would then be required to lift the assembled product, weighing up to 1500 lbs [680 kg]. To add to the challenge, the fabrication materials range from 28 to 57 feet [8.5 - 17.4 m] in length, are between 7 and 9 feet [2.1 - 2.7 m] in width, and the individual sheets range in thickness from just 0.09 to 0.3 inches [2.9 - 7.6 mm].The Challenges
The Engineering Department at Wood's Powr-Grip welcomed the challenge. As a start, it was decided to base the design on our popular series of flat lifters. However, none of the standard flat lifters were even close to the dimensions required for this vacuum lifter. It would need to have enough length and an adequate number of vacuum pads to prevent material distortion, while allowing the operator to deactivate pads not needed when lifting shorter loads. The stresses caused by the weight of the lifter and the material load would have to be analyzed, and a suitable frame design would need to be determined. To top it all off, the powerful vacuum force required to effectively operate a vacuum lifter this large would have to be balanced by the type and number of vacuum pads used, in order to prevent distortion and damage to the delicate Chemlite Plastic® used in the fabrication process.The Challenger
Weighing in at 1375 lbs [624 kg], at a length of 595" [1511 cm] and a width of 75-1/2" [192 cm], the final product was realized - the FL209ACS. This vacuum lifter was supplied with twenty 9" [23 cm] vacuum pads. These particular pads were chosen because they were less likely to damage the thin materials that were to be lifted. Properly spaced, they would provide appropriate support for the load and prevent buckling or distortion. As an added bonus, these vacuum pads would evacuate more rapidly than larger ones, increasing productivity with apply and release times of just 2 seconds each. Spring-shaft pad mounts were employed to help even out the amount of load weight supported by each of the vacuum pads and to reduce the stress experienced by flexible loads during a lift. A pump rated at 10 SCFM [283 liters/minute] free airflow was used to assure that there would be adequate suction over the length and width of the vacuum lifter. A custom valve enclosure was devised to accommodate a larger than normal 1/2" [127 mm] vacuum line for maximum flow. All the vacuum lines were equipped with quick-connect couplings that would allow the operator to "turn off" those vacuum pads that would not be needed for a lift, and a movable control pendant was supplied with a generous 15ft [4.6 m] cord, to allow the operator to remain at a safe distance during the lifting cycle. The two-tier lift frame was designed with strategically placed supports for strength and was constructed from aluminum to keep the weight down. Still, a vacuum lifter of this size is unavoidably heavy. To make it easier to move the lifter around the shop, wheels were incorporated into the parking stand design. Because of the lifter's large size and weight, this simple feature proved to be very helpful during the construction and loading of the lifter for shipment. When it came time to send the vacuum lifter off, it was broken down into three sections, bubble wrapped, wheeled outside and then loaded onto a semi-trailer using a forklift. The FL209ACS is now in use at the Great Dane manufacturing plant. It is a strong testament to the design and engineering expertise of the qualified staff at Wood's Powr-Grip. Over the years, Wood's Powr-Grip has manufactured many products to meet the specific needs of our customers. If you have a task that requires a unique vacuum lifting solution, visit the Wood's Powr-Grip Authorized Dealer nearest you or feel free to contact one of our Technical Sales Representatives.David Peters had more than 30 years experience in sales and marketing. He was the marketing associate for Wood's Powr-Grip Co., Inc., responsible for interactive marketing, tracking, market research and new product introduction.