The subassembly consists of a pivot shaft, housing, lever and a rectangular flange plate.
(original from Assemblymag.com)
U.S. manufacturers that source low-cost components offshore often face several challenges. Among the most common are language barriers, lack of timely responses, long lead times and problems with U.S. Customs and Border Protection. Another problem is receiving a perfect prototype initially—followed by subsequent shipments of poor-quality parts.
WEXCO Industries Inc., a manufacturer of heavy-duty windshield wiper systems for OEMs, knew all about these problems in 2010 after using offshore vendors for 5 years. That year the Pine Brook, NJ, company decided to change its approach and source a local vendor, AmTech International, for the pivot shafts and housings it needed on its new Compact Drive and Dual Drive motorized wiper assemblies.
WEXCO knew that AmTech manufactured precision custom shafts, gears and assemblies offshore. But, WEXCO also knew two other things: AmTech made precision components that met WEXCO’s tight tolerances; and AmTech could provide just-in-time deliveries from its nearby warehouse in Dayton, NJ.
“A pivot shaft and housing must be made to precision for a windshield wiper system to work properly and perform well over the long term,” says Jeff Forbes, vice president of business development for WEXCO Industries. “This is why our two companies collaborated on the design of both components.”
Pivot shafts have a diameter of 12 millimeters and come in five lengths, ranging from 85 to 144 millimeters. One end of the shaft is squared off; the other end has threads. Above the threads are 37 narrow splines that encircle the shaft.
The pivot housing also comes in five sizes, and it measures 19 to 76 millimeters long. It is threaded from top to bottom and features convex-shaped open ends.
Both components are used in the pivot shaft subassembly, along with a rectangular flange plate and a pivot lever. The Compact Drive assembly features one pivot-shaft subassembly, while the Dual Drive assembly features two. The assemblies also feature stamped-metal pieces (frame bracket, link and crank), an electric motor with connector and hardware (retaining clip, screws, washers and hex nuts).
Building the pivot-shaft subassembly is a four-step process. First, the squared off end of the shaft is spin-riveted onto one end of the pivot lever so that the joined pieces form an L shape. Next, an eccentric ball stud is spin-riveted onto the other end of the pivot lever. WEXCO uses a BalTec Corp. machine to perform spin riveting.
Separately, the flange plate is threaded in its center and spun down on the housing as far as specified before being staked down. Two bushings are then placed onto the shaft, which is machine pressed into the housing so the bushings are enclosed and the threaded end is visible. Finally, shaft stack height is measured to verify that it’s within allowable tolerances.
The assemblies are shipped to OEMs of construction equipment, agricultural machinery, snow-dozers, workboats and recreational vehicles. Workers install the assemblies fairly early on the production line, but do not mount a wiper arm (with attached blade) onto each pivot shaft of the assembly until the end of production. Custom Drive assemblies can handle arms and blades up to 30 inches long, Dual Drive assemblies up to 40 inches long.
WEXCO makes 40,000 to 50,000 wiper assemblies per year. Current customers include Case New Holland, JCB, Newmar RV and Spartan Trucks, although the company also hopes to sell to manufacturers of over-the-road trucks, mining and marine equipment.