Some other really neat bugs were made by The Mecograph Company in Cleveland Ohio. In 1904, William Coffe invented his first mechanical semi-automatic telegraph key which he called the Mecograph. The interesting thing is that his patent preceeded Horace Martin's mechanical Vibroplex patent by 4 months, which set off a long round of court battles for the right to produce these new telegraph keys. More information about this legal battle can be read in Bill Holly's book "The Vibroplex Company", available from Artifaxbooks.
(Click on the pictures below to see larger versions of the photo)
First Model Mecograph (1904)
Although they produce automatic dots and manual dashes like a Vibroplex, Mecograph keys operate on a very different principle. Vibroplex keys produce automatic dots by striking the dot lever against a fixed post, causing the pendulum to oscillate from side to side. However with the Mecograph, the dot lever has a spring which puts tension on the pendulum when at rest. When the dot lever is moved, tension is released from the pendulum, causing it to oscillate from side to side just like a Vibroplex. Because of this design, Mecograph keys require less force to operate than a Vibroplex. However, the first Mecograph Model was very difficult to adjust which is why it was only around for a short time before improvements were made.
Mecograph Combo Model (1905-1906)
|(Left picture Gil Schlehman K9WDY collection. Right picture Lynn Burlingame N7CFO collection)|
The Combo Model consisted of a straight key and a bug inside a metal box. Although the known serial numbers suggest that hundreds of these were made, only about 4 are known. (Photos courtesy of N7CFO)
Model 3 - Square Weight Version (1906-1908)
The Model 3 was by far the most popular and widely known of the Mecograph models. The design changed over the years but they all have a keying lever that is at right angles to the vibrating pendulum. The first Model 3 version was an all-brass key that had a large #3 cast into the underside of the base.
It can also be recognized by the square weight and spade-shaped speed adjustment part. Later, the brass base was replaced with a steel base which was finished either with black lacquer or nickel plated. The keying mechanism parts of these bugs were nickel plated.
Model 4 (1906)
The Model 4 appeared for a short time in 1906. At first glance it looks much like the Model 3, although there is a very important difference. Notice there is no spring tensioner arm (Although the advertisements for the key showed a tensioner arm). So although the lever is at right angles to the pendulum, the key actually operates like a Vibroplex; i.e. the dash lever strikes against a fixed post to cause the mechanical oscillations. The Model 4 also represents a cost reduction, replacing the expensive cast parts with an assembled frame. In addition the dash lever pivots on a set of 4 tiny ball bearings. This probably let to the demise of this key, as if the key went out of adjustment, it was easy to lose the ball bearings.
Model 3 - Round Weight Version (1908-1911)
In 1908 the Model 3 was redesigned to be a bit smaller with 2 large round weights although the operating principle was the same as the earlier square weight Model 3. The long spring tensioner arm was replaced by a small spring loaded cam mounted on a post next to the weights. The standard finish for this key was something referred to as a "tiger stripe" finish, where the steel base was first copper plated, then blued, then the "stripes" were produced either by applying a chemical to wipe off the blueing or by some mechanical buffing tool. Unfortunately no protective coating was applied afterwards, so the bases on many of these Mecograph tiger stripe keys were badly rusted so the stripes cannot be seen. There are some fine examples of the tiger stripe finish, however, on keys that were kept in dry environments and protected from the elements.
Model 5 (1908)
Advertisements for the Model 5 appeared in magazines in 1908; however only one incomplete example of this model has ever been found. Ron Ayling, G3YUH, made a beautiful identical copy of the key, which can be seen at upper right.
Mecograph Premier - (1911-1913)
Model 3 - Round Weight Version -Solid Base (1913)
The Vibroplex Premier (1913)
|An unusual key very similar to the Mecograph Premier, made after Vibroplex bought the company in 1913. This is the only known example of this rare key.|