Lift-Assist Devices Aid Assemblers
For years, managers told assemblers to “work smarter, not harder” without providing them with the tools to achieve this goal. This was especially challenging for workers who had to lift heavy objects around their workstations. Today, however, they can “lift smarter and work easier” thanks to a wide variety of state-of-the-art cranes, hoists, intelligent assist devices and work positioners.
Assemblers at one Turkish automotive plant welcome these tools to ease the installation of front and rear suspensions for two auto models. Initially, each suspension was installed with a pneumatic loader. But its slow speed, lack of control and difficulty adapting to different suspension weights slowed production considerably—preventing workers from meeting the installation rate of 50 suspensions per hour.
To solve the problem, managers replaced the pneumatic loader with two Easy Arm lifting devices made by Gorbel Inc. Both devices are 10 feet high, have a 10-foot reach and feature G-Force technology that offers more control, greater speed and easier lifting than the loader. Lift capacity is generated by a servo-controlled actuator at the top of the device. A coiled air line connects the actuator to a handle that maneuvers the part.
One Easy Arm is equipped with a Q330 actuator that lifts and moves 220-pound front suspensions. The other device has a Q165 actuator, and it handles 165-pound rear suspensions.
Assemblers at the Oerlikon Fairfield plant in Lafayette, IN, also make good use of Gorbel’s Easy Arm lifting devices. The company makes Torque Hub gears and drives for OEMs worldwide.
Each product weighs 50 to 80 pounds when assembled. Until recently, assemblers at one work cell manually moved each part to a worktable from nearby stacks, rotated and flipped the increasingly heavier assembly, and moved the finished product to a storage area.
Facility engineering supervisor Anthony Schenk says this approach resulted in each worker assembling only six or seven units per shift, about 20 per day over three shifts. More importantly, the manual lifting produced excessive wear and tear on the worker day after day.
Two years ago, the company installed Easy Arms to improve worker ergonomics and increase productivity. A handle with end-of-arm tooling enables the assembler to easily retrieve parts, and rotate and flip the assembly. As for productivity, Schenk says a worker now assembles 20 units per shift—a 300- percent increase.
Assemblers primarily use four types of cranes. Jib cranes feature a horizontal member (jib) that supports a lift device (hoist, air balancer, intelligent assist device). It can be freestanding or fixed to a wall or floor-mounted pillar. A gantry crane spans the work area. It is mobile and features a trolley or fixed machinery housing that runs horizontally along I-beams or an enclosed track. The lift device attaches to the trolley or housing.
Workstation cranes are similar to gantry cranes, in that they span the work area, but differ in that they are freestanding or floor- or ceiling-mounted. Overhead (or bridge) cranes feature a moveable bridge that travels along an overhead runway structure incorporated into the building’s ceiling. A variation is the underhung crane, where the runway beam is often suspended from the roof to eliminate columns and increase floor space.
Manufacturers must consider several factors to select the best crane for an application. These include the size of the object being lifted; lifting height and frequency; velocity, acceleration and travel distance of the load; overall height, clearance and usable space; and the distance of the object from the assembler.
Manufacturers in various industries use WSJ360 and WSJ200 jib cranes from Gorbel for assembly because they offer a lifting capacity of 1,000 pounds and a work span of 20 feet. The WSJ360-F is a free-standing model that provides 360 degrees of rotation. Model WSJ200 is a ceiling-mounted version with the same capabilities.
Every crane requires a lift device to raise, turn or transport a heavy object.
Intelligent assist devices, like the Easy Arm from Gorbel, are growing in popularity, according to Mark Grandusky, G-Force product sales manager for Gorbel Inc. These devices come with Q or iQ series actuators that lift loads from 165 to 330 pounds at speeds up to 200 fpm. The iQ series also allows an assembler to control one G-Force or Easy Arm unit with two handles or two G-Force units with one handle. This feature is for applications when tooling requires more than one point of control.
In float mode, the Easy Arm handle allows an operator to guide an object precisely with both hands. On the handle’s backside is a photosensor that prevents load movement unless the worker grabs the handle and breaks the sensor beam. An LCD panel displays load weight and enables easy control of acceleration.