Dearborn Mid-West Company

Specialty Transfer Systems


Overview

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Specialty Transfer systems are designed to move loads vertically and horizontally between different handling systems, or within a single multilevel system. Although these transfer systems such as Drop/Lift Transfers can add flexibility to any standard overhead conveyor, they offer the greatest benefit when paired with either Overhead Power & Free Systems, Skillets, or Automated Electrified Monorail Systems. Drop/lift transfers can change two separate handling systems into a Single Integrated System.

Chain Lift – General Assembly


Transfer System Selection

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The operation of Drop/Lift Transfers can be fully automated, semi-automated, or manual. These units come in a wide range of electrical, mechanical, pneumatic, and hydraulic designs. Chains, cables, and belts have all been used to support and transfer loads from one conveyor to another.

While Drop/Lift Transfers can move loads from one overhead material system to another, they are typically used to transfer loads from an overhead system to a floor mounted system, or vice-versa. They are usually designed to handle a specific type of load, application, production problem, or plant layout consideration.


Manufacturing and Production Flexibility

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Certain processes in a production system are ideally suited for an overhead application, while others are better suited for a floor application. The use of Specialty Transfer systems allows both types of systems to be seamlessly integrated, thus optimizing their application, and allowing the material handling system to adapt to the production / process requirements and not vice versa.


Reliability and Maintainability

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Drop / Lift Transfers are designed to be reliable and easy to maintain. However, since these systems are typically comprised of sophisticated automated equipment, they require properly trained technicians who stay ahead of maintenance and inspection needs. These technicians also need to ensure that the equipment stays correctly calibrated.


Protecting Product Quality

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During the transfer cycle, the load is positioned and held firmly to prevent any handling-related product damage. Although most transfers run in an automated mode, manual controls can be used to override the automated mode if needed to address a potential product quality problem.

The end-user can influence product quality as well by providing perch or contact points on the products to help with the transfer process. These perch points are generally cradled in plastic mounts on the transfer mechanism for additional product protection.


Operator Safety Issues

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As with other forms of Automated Material Handling equipment, Drop/Lift Transfers need to meet a very high standard to ensure employee safety. Transfers are usually equipped with complete guarding, light screens, warning lights, emergency stops, electrical / mechanical lockout devices, in full compliance of applicable safety codes and standards. These transfer units, with their quick transfer speeds and automatic operation, require extremely stringent safety measures and thorough employee training.

Chain Lift - Tire Delivery Lowerator


Equipment Cost Considerations

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Drop / Lift transfers are relatively expensive equipment and often account for a major portion of the overall cost of the system. But, the alternative of handling loads manually may be even more costly as a result of inefficient manual labor, poor product quality, inefficient product flow, or work-related injuries.


Types of Specialty Transfer Systems

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Cable Hoist-Operated Drop/Lifts

Cable hoist-operated Drop/Lifts are simple, reliable, and reasonably priced alternatives to expensive highly automated drop/lifts. Their use is typically limited to low-throughput applications in which the operator and products can be properly protected.

Typical system parameters are as follows:

Lift: 10 to 20 ft. (3 to 6.1 m)
Cycles per hour: 50
Maximum Load: 4,000 lbs. (1,814 kg)

Continuous Vertical Lift Conveyors

A continuous Vertical Lift Conveyor is a lift and carry device that transports loads in one direction only - either up or down. Its movement is continuous throughout the product transfer cycle. It is this continuous movement that separates the Vertical Lift Conveyor from other types that have programmed starts and stops during their transfer cycles. The Vertical Lift Conveyor is used where elevation changes are great, and where quick production rates require the continuous movement of multiple jobs simultaneously.

A continuous Vertical Lift Conveyor uses multiple lengths of chain that wrap around an assortment of sprockets to produce the desired transfer lift or drop. Crossbars are attached to the strands of chain at intervals spaced for specific product centers or other job requirements. The continuously-moving matched chains and support bars deliver loads to the required elevation quickly and smoothly.

Typical system parameters are as follows:

Lift: 20 to 50 ft. (6.1 to 15.2 m)
Cycles per hour: 80-85
Maximum Load: 2,500 lbs (1,134 kg)

Hydraulic Cylinder Drop/Lifts

This type of transfer uses a powerful hydraulic cylinder installed in the plant floor to move loads up and down. A carriage that is specifically designed to mach the perch points on the load being transferred is attached to the rod end of the cylinder. Carriage guides are built into the supporting structure to prevent the carriage from twisting during the transfer cycle. This hydraulically-controlled transfer has built-in acceleration and deceleration capability for accurately positioning the loads at both the pickup and discharge points.

Over the years, hydraulic cylinder Drop/Lifts have developed a good reputation for reliability, and the addition of stand-by hydraulic pumps and controls have made them even more reliable.

Typical system parameters are as follows:

Lift: 15 to 35 ft. (3 to 6.1 m)
Cycles per hour: 70
Maximum Load: 5,000 lbs. (2,268 kg)

Hydraulic Lift – Frame Transfer

Electric-Powered Chain Drop/Lifts

Electric-powered Chain Drop/Lifts use a series of electric-powered chain drives to lift and lower loads. These transfer devices feature acceleration, deceleration, and braking functions. The speed control is typically achieved through a variable speed DC drive or variable frequency AC drive. The use of electrical control systems with conventional chain drives produces a reliable and smooth load transfer at precisely controlled speeds.

Typical system parameters are as follows:

Lift: 10 to 20 ft. (3 to 6.1 m)
Cycles per hour: 75-80
Maximum Load: 3000 lbs. (1,361 kg)

Electric-Powered Belt Drop Lifts

The design of electric-powered Belt Drop/Lifts closely resembles that of the chain drop lift. The control logic is also very similar. The central difference is the use of special reinforced belts, rather than chain. These high-strength, wear-resistant belts are quieter, while retaining the speed and load capacity of chains. In addition, belts eliminate the lubrication requirements of chains and sprockets, as well as the wear and alignment problems associated with chain.

Typical system parameters are as follows:

Lift: 10 to 20 ft. (3 to 6.1 m)
Cycles per hour: 75-80
Maximum Load: 3000 lbs. (1,361 kg)

Belt Lift - General Assembly

Automatic Fork Lift and Transfer

Automatic lift and transfer devices, commonly referred to as "Fork Transfers" are designed to not only transfer loads vertically, but to also move them horizontally. Fork Transfers can accommodate virtually any unit load, but their load capacity is limited to approximately 2000 lbs. The load limitation is due mainly to the low profile design of the forks and the cantilevered position of the load.

Fork Transfers equipped with telescoping forks can move a load from one conveyor to a home position and onto another conveyor. A telescoping fork is a precisely machined steel rack-and-pinion device that can move loads horizontally from the center about 7 ft (2.1 m) in each direction. Two or more forks may be used in tandem, depending on the load size and weight. Specially designed perches help to ensure that the load is carried securely and accurately during the transfer cycle.

By offering both horizontal and vertical movement, Fork Transfers add a great deal of flexibility to manufacturing processes. In some applications, the precise horizontal and vertical travel of a fork transfer may make it the only practical handling solution.

Typical system parameters are as follows:

Lift: 3 to 20 ft. (0.9 to 6.1 m)
Cycles per hour: 80
Maximum Load: 2000 lbs. (907 kg)

Automatic Fork Transfer