Willis Lamm's
Traffic Signal Collection

  Traffic Signal Lenses
Part Two

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Large Bead Lenses

Corning Glass patented a signal lens that contained prismatic beads in 1918. Known as the Type B, this lens was in many respects the forerunner of the modern traffic signal lens. The beads enhanced and diffused light received from the signal reflector but tended to dissipate most reflected low angle sunlight away from traffic. Crouse-Hinds and Marbelite used their own versions of the Type B design for many years.

This particular lens came out of an early 1920's AGA signal.

Marbelite Large Bead Lenses

Marbelite used a Corning large bead lens almost identical to the Type B. Marbelite added its logo to the glass face - a raised M and long diagonal lightning bolt which can just barely be seen in the large view of this image. The Marbelite "lightning bolt" lens was Corning's Type E lens.

Crouse-Hinds Type T Lenses

Crouse Hinds patented what is commonly known as "smiley" lenses. These "Type T" lenses, were originally based on the large bead Corning B lenses. Back in the days when many intersections had a single 4-way signal hanging in the center that both vehicles and pedestrians had to be able to clearly see, it was important that lenses project a limited amount of light down and to the sides. Crouse-Hinds modified the Corning lens with "smiley" facets to make the indication more visible to pedestrians and vehicles stopped practically underneath the signal.

In 1940 Crouse-Hinds advertised the Type T lens as "a signal indication readily discernible for many blocks and over any angle. There is a powerful beam of light directed downward and to the sides for pedestrians to see."

Crouse-Hinds T-1 Lenses

In the mid 1940s the Institute of Traffic Engineers, or ITE, conducted research and adopted standards for traffic signal design. While many details were left to manufacturers, the ITE addressed uniform standards regarding lens colors, distribution and projection of light and prevention of "phantoms," a condition where low angle rays of the sun created an illusion that an indication was lit when it was not.

Crouse-Hinds later modified the Type T to have smaller beads that produced a smoother looking light and a little less phantom effect, and these "T-1" lenses were the most predominant smiley lenses of the late 1940s and 50s. The image is of the T-1 version of the "smiley" lens.

Crouse-Hinds T-2 Lenses

When Crouse-Hinds brought out the Type M signals in the early 1950s they modified the T type lenses and came out with what they called the Type T-2, lens part number 553401. The beading was essentially the same as the T-1 but the smiley bottom section was all but eliminated. The beads went clear to the bottom of the lens but a faint trace of the traditional smiley pattern remained on the earlier T-2 lenses. Eventually the smiley traces disappeared altogether.

Collectors typically refer to lenses with just a trace of smiley lines as "faint smileys."

Kopp 27 Diamond Lenses

Kopp Glass produced a series of diamond pattern lenses starting with the Type 27. Each lens was divided into diamond patterns and each diamond contained three or four small vertical beads (depending on the type) in a kind of art deco pattern. The Type 27 lenses came lettered and non lettered. The successors to the Type 27 lenses were Type 66 and TL-4666 lenses, used in a variety of signals, primarily Southern Autoflows.

The 66 and TL-4666 lenses differed slightly from the Kopp 27 lenses. The diamonds in the 27 contained three prisms in the bottom that extended 3/4 up the diamonds. The 66 and 4766 lens colors had four prisms that extended just past the middle of each diamond and the colors were slightly different, meeting the newer chromatic standards.

Marbelite 6540 Lenses

While Marbelite is best known for its Corning "large lightning bolt" lenses and Kopp "short lightning bolt" lenses, they also used Type 6540 lenses made under their own trade name. These lenses utilized a unique bead pattern that was a sort of transition between the old large bead lenses and "brick pattern" lenses that GE was developing. The 6540 lenses were soon replaced with Kopp TL-4777 "sawtooth" lenses to which Marbelite had its lightning bolt logo cast onto the glass.

Kopp TL-4777 Lenses

The TL-4777 "sawtooth" lens came out in the 1950s and is still in production today in both glass and lexan. Marbelite used the TL-4777 and had its logo cast into the glass. A number of other manufacturers also used TL-4777 lenses including Sargent-Sowell, TSI and McCain. The sawtooth pattern produced a well diffused light and had minimum phantom problems.

Continue to Part Three

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