Edward D. "Don" Winkler filed a patent for the first Storage Battery Connector (SB®-2) in 1953. While perhaps not on the same scale as another 1953 discovery -- the structure of DNA -- this pioneering two-piece device has empowered everything from forklifts to wheelchairs to golf carts. It has evolved numerous times and been imitated even more. Today, companies are still "introducing" their own versions of Winkler's 50-year-old invention.

In honor of the golden anniversary of the Type SB connector, this article looks back at some product inventions and innovations produced by Winkler and the company he worked for, known in 1953 as the Albert & J.M. Anderson Mfg Co, and known today as Anderson Power Products (APP). Through this prism we can view 50 years of changing technology and gain insight into how customer input can influence product design.

A Connector Is Born

APP's origins can be found in the mining and railway industries. In 1877 the company converted an old brewery in downtown Boston into a foundry, where one of the first projects was to cast various parts for the Boston Trolley Transit System. Product development and inventions such as the trolley pole, invented by Johan M. Anderson in 1890, put APP on the map. The trolley pole, used in the overhead system of electric railways, provided a simple, compact, efficient, and durable supporting mechanism.

Customer demand drove introduction and evolution of the company's two primary product lines -- storage battery connectors and powerpole connectors.

Introduction of the SB-2 in 1953 grew out of a request from industrial forklift manufacturers for a more robust connection. An excerpt from actual notes from a meeting between Anderson Mfg and Lewis-Shepard Co, an industrial truck manufacturer, illustrate the degree of cooperation involved:

"This meeting was called at the request of Mr. Hastings who was not satisfied with any of the available plugs and receptacles sold to the Industrial Truck field today. It is thought that a plug and receptacle manufacturer should study this problem with the idea of incorporating the latest materials available . . . He feels that the outer shell or jacket of the plugs and receptacles should be made of the latest type plastics of high impact value. . . . Another feature desired is ease of disconnect. . . . It is their suggestion that we should probably design a plug and receptacle which would cover all of the requirements of the small material handling trucks up to and including 400 lb capacity trucks."

Notes from a meeting that took place a few months later say that "Mr. Hastings gave us a list of 12 features which he feels a new plug and receptacle should have." A short time later, Don Winkler and Anderson Power were applying for their patent for the Type SB Connector, which was recognized by Underwriters' Laboratories on January 3, 1954.

The original design of the SB-2 rated 600 V and 150 A and utilized a 2-piece plasticon housing with stainless steel springs and brass, solderable contacts. Early users of the Type SB included Lewis-Shepard as well as Clark Equipment Co, and a close working relationship with both of these companies led to numerous product enhancements in the early to mid-50s. These ranged from changes in the product housing to increased strength to improvements in the cable clamp.

APP's Storage Battery connector saw a number of different iterations in the 50s and 60s, including the single-piece design SB50, which featured the extra-high heat resistance of General Electric's Lexan material; the single-piece SB350 with four different voltage keys; and the SB175 with contacts that were now made of pure copper (replacing brass contacts). During this period, the SB connector had gained wide acceptance in the lift truck industry and had for all intents and purposes replaced spring-loaded contact button technology and pin/socket contact technologies.

The Evolution Continues

Over the last three-plus decades, customer-driven improvements to the Storage Battery connector have been arriving at an ever-increasing rate. Along with disco and bell-bottoms in the 70s came APP's SBX family (i.e., SBX175, SBX350, etc.), which added fail-safe features like fingerproof protection, and auxiliary contacts, which automatically turned chargers off when the connector is disconnected.

In the early 80s, APP's new wave of connectors addressed the needs of our friends across the pond. The company developed the SBE family (i.e., SBE80, SBE160, SBE320, etc.) with fingerproofing to meet European Norm EN1175-1, plus auxiliary contact. This series is used extensively in Europe on 80 V forklifts.

In the mid 90s, APP developed the SBO320, which has grounding for 125 Vac and 100 amp disconnect under load for daisy chaining uninterruptible power supplies (UPS) systems. Around this time, a number of UPS manufacturers had already adopted the SB50, which was also being used in various applications such as golf carts, wheelchairs, and scooters.

And in 2002, APP added the SB120 with low insertion force/extraction force contact for UPS systems. That same year, the company introduced the SBE700, specifically designed for fast charging and "opportunity charging" applications, which exceed the SBE320 level of current. Bethlehem Steel recently installed these genderless, hot-pluggable SBE700s into their 60,000 lb coil tractors, greatly reducing the tractors' downtime. And just within the last year, APP released an SBS50 for UPS batteries ranging from 96-192 V.

The Powerpole Is the Rail Thing

Meanwhile, back in the mid-60s, Anderson Power Products answered the call of the Bay Area Rapid Transit (BART) in San Francisco, CA with the invention and introduction of the company's second principal product line, the Powerpole family of connectors. Featuring a flat wiping contact system, an interchangeable genderless design, silver-plated contacts, and modular designs, APP had UL Safety Agency approval on the Powerpole by 1964. Powerpole connectors (PP15/45 and PP75) were first utilized aboard BART trains, and are still making the connection on these trains today.

A Good Day at the Office

In the early 70s, APP and the Powerpole entered the office furniture and equipment market. The PP15/45 was used by such manufacturers of office furniture as Steel Case, Hayworth, and Herman Miller, and is still used today by several manufacturers of customized office wiring. The operating voltages for this connector are 120 to 208 Vac in a number of applications, and 30 A per pole on 10 AWG copper cable. Powerpoles also found their way into wheelchairs, floor sweepers and power supplies during this decade.

Many new markets and applications arose for the Powerpole in the 90s, including rack and panel applications in UPS systems, micro-wireless telecom equipment, and medical applications. Product enhancements appeared as the Powerpole, like its SB sibling, continued to evolve. For example, in the mid-90s, APP developed a touch safety/fingerproof Powerpole for high voltage dc applications. Also, for higher temperatures, APP added a Powerpole with a higher heat deflection plastic.

Looking Ahead

APP has built tens of millions of SB connectors since the 1950s and hundreds of millions of Powerpole connectors since the 1960s, and the company continues to add new products to both product families. Today APP has greater throughput than ever before, and is developing more products geared toward specific unique market segments.

According to director of marketing Brian Davies, "In the future, I see us continuing our tradition of focusing on customer needs, while making more products designed specifically for unique customer applications, such as smaller 100 amp dc power connectors for electronic systems, and more robust connectors for industrial systems and environmental protection systems."

The company recently expanded its manufacturing capabilities with two plants in Asia, and Davies sees increased global expansion in the future. "By expanding internationally and deploying development partners in different parts of the world, like Asia," he says, "we will be much better equipped to service those global markets. Our international customers will benefit from localized engineering, design, product development and manufacturing, and logistics support. And we will benefit from closer contact with a vast international customer base and will be better equipped to understand and address their changing needs."